From fa17b0200f27e5f21e8397078b0cad4933ca30bd Mon Sep 17 00:00:00 2001 From: Austin Cherry Date: Wed, 23 Jan 2019 15:42:10 -0600 Subject: [PATCH] AUTH-1557: Short Lived Certs --- .gitignore | 1 + Gopkg.lock | 5 +- carrier/carrier.go | 53 +- carrier/carrier_test.go | 14 +- cmd/cloudflared/access/carrier.go | 33 +- cmd/cloudflared/access/cmd.go | 33 +- cmd/cloudflared/path/path.go | 30 + cmd/cloudflared/token/token.go | 36 +- sshgen/sshgen.go | 163 +++ .../x/crypto/internal/chacha20/asm_arm64.s | 308 +++++ .../crypto/internal/chacha20/chacha_arm64.go | 31 + .../internal/chacha20/chacha_generic.go | 264 ++++ .../crypto/internal/chacha20/chacha_noasm.go | 16 + .../crypto/internal/chacha20/chacha_s390x.go | 29 + .../x/crypto/internal/chacha20/chacha_s390x.s | 260 ++++ .../x/crypto/internal/chacha20/xor.go | 43 + vendor/golang.org/x/crypto/ssh/buffer.go | 97 ++ vendor/golang.org/x/crypto/ssh/certs.go | 535 ++++++++ vendor/golang.org/x/crypto/ssh/channel.go | 633 ++++++++++ vendor/golang.org/x/crypto/ssh/cipher.go | 770 ++++++++++++ vendor/golang.org/x/crypto/ssh/client.go | 278 +++++ vendor/golang.org/x/crypto/ssh/client_auth.go | 525 ++++++++ vendor/golang.org/x/crypto/ssh/common.go | 383 ++++++ vendor/golang.org/x/crypto/ssh/connection.go | 143 +++ vendor/golang.org/x/crypto/ssh/doc.go | 21 + vendor/golang.org/x/crypto/ssh/handshake.go | 646 ++++++++++ vendor/golang.org/x/crypto/ssh/kex.go | 540 ++++++++ vendor/golang.org/x/crypto/ssh/keys.go | 1100 +++++++++++++++++ vendor/golang.org/x/crypto/ssh/mac.go | 61 + vendor/golang.org/x/crypto/ssh/messages.go | 792 ++++++++++++ vendor/golang.org/x/crypto/ssh/mux.go | 330 +++++ vendor/golang.org/x/crypto/ssh/server.go | 594 +++++++++ vendor/golang.org/x/crypto/ssh/session.go | 647 ++++++++++ vendor/golang.org/x/crypto/ssh/streamlocal.go | 116 ++ vendor/golang.org/x/crypto/ssh/tcpip.go | 474 +++++++ vendor/golang.org/x/crypto/ssh/transport.go | 353 ++++++ 36 files changed, 10286 insertions(+), 71 deletions(-) create mode 100644 cmd/cloudflared/path/path.go create mode 100644 sshgen/sshgen.go create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/asm_arm64.s create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/chacha_arm64.go create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.s create mode 100644 vendor/golang.org/x/crypto/internal/chacha20/xor.go create mode 100644 vendor/golang.org/x/crypto/ssh/buffer.go create mode 100644 vendor/golang.org/x/crypto/ssh/certs.go create mode 100644 vendor/golang.org/x/crypto/ssh/channel.go create mode 100644 vendor/golang.org/x/crypto/ssh/cipher.go create mode 100644 vendor/golang.org/x/crypto/ssh/client.go create mode 100644 vendor/golang.org/x/crypto/ssh/client_auth.go create mode 100644 vendor/golang.org/x/crypto/ssh/common.go create mode 100644 vendor/golang.org/x/crypto/ssh/connection.go create mode 100644 vendor/golang.org/x/crypto/ssh/doc.go create mode 100644 vendor/golang.org/x/crypto/ssh/handshake.go create mode 100644 vendor/golang.org/x/crypto/ssh/kex.go create mode 100644 vendor/golang.org/x/crypto/ssh/keys.go create mode 100644 vendor/golang.org/x/crypto/ssh/mac.go create mode 100644 vendor/golang.org/x/crypto/ssh/messages.go create mode 100644 vendor/golang.org/x/crypto/ssh/mux.go create mode 100644 vendor/golang.org/x/crypto/ssh/server.go create mode 100644 vendor/golang.org/x/crypto/ssh/session.go create mode 100644 vendor/golang.org/x/crypto/ssh/streamlocal.go create mode 100644 vendor/golang.org/x/crypto/ssh/tcpip.go create mode 100644 vendor/golang.org/x/crypto/ssh/transport.go diff --git a/.gitignore b/.gitignore index cc85adaa..647b5d00 100644 --- a/.gitignore +++ b/.gitignore @@ -9,3 +9,4 @@ guide/public \#*\# cscope.* cloudflared +!cmd/cloudflared/ \ No newline at end of file diff --git a/Gopkg.lock b/Gopkg.lock index 79f14634..26a0104b 100644 --- a/Gopkg.lock +++ b/Gopkg.lock @@ -376,17 +376,19 @@ [[projects]] branch = "master" - digest = "1:9afbc3e330bd691e0eb0e704d05cc182b5c62ea71c5691c99fa5e82f06b628b6" + digest = "1:a84d5ec8b40a827962ea250f2cf03434138ccae9d83fcac12fb49b70c70b80cc" name = "golang.org/x/crypto" packages = [ "curve25519", "ed25519", "ed25519/internal/edwards25519", + "internal/chacha20", "internal/subtle", "nacl/box", "nacl/secretbox", "poly1305", "salsa20/salsa", + "ssh", "ssh/terminal", ] pruneopts = "UT" @@ -588,6 +590,7 @@ "github.com/sirupsen/logrus", "github.com/stretchr/testify/assert", "golang.org/x/crypto/nacl/box", + "golang.org/x/crypto/ssh", "golang.org/x/crypto/ssh/terminal", "golang.org/x/net/context", "golang.org/x/net/http2", diff --git a/carrier/carrier.go b/carrier/carrier.go index f54cd653..20af6c70 100644 --- a/carrier/carrier.go +++ b/carrier/carrier.go @@ -12,10 +12,17 @@ import ( "strings" "github.com/cloudflare/cloudflared/cmd/cloudflared/token" + "github.com/cloudflare/cloudflared/sshgen" "github.com/cloudflare/cloudflared/websocket" "github.com/sirupsen/logrus" ) +type StartOptions struct { + OriginURL string + Headers http.Header + ShouldGenCert bool +} + // StdinoutStream is empty struct for wrapping stdin/stdout // into a single ReadWriter type StdinoutStream struct { @@ -34,27 +41,27 @@ func (c *StdinoutStream) Write(p []byte) (int, error) { // StartClient will copy the data from stdin/stdout over a WebSocket connection // to the edge (originURL) -func StartClient(logger *logrus.Logger, originURL string, stream io.ReadWriter, headers http.Header) error { - return serveStream(logger, originURL, stream, headers) +func StartClient(logger *logrus.Logger, stream io.ReadWriter, options *StartOptions) error { + return serveStream(logger, stream, options) } // StartServer will setup a listener on a specified address/port and then // forward connections to the origin by calling `Serve()`. -func StartServer(logger *logrus.Logger, address, originURL string, shutdownC <-chan struct{}, headers http.Header) error { +func StartServer(logger *logrus.Logger, address string, shutdownC <-chan struct{}, options *StartOptions) error { listener, err := net.Listen("tcp", address) if err != nil { logger.WithError(err).Error("failed to start forwarding server") return err } logger.Info("Started listening on ", address) - return Serve(logger, listener, originURL, shutdownC, headers) + return Serve(logger, listener, shutdownC, options) } // Serve accepts incoming connections on the specified net.Listener. // Each connection is handled in a new goroutine: its data is copied over a // WebSocket connection to the edge (originURL). // `Serve` always closes `listener`. -func Serve(logger *logrus.Logger, listener net.Listener, originURL string, shutdownC <-chan struct{}, headers http.Header) error { +func Serve(logger *logrus.Logger, listener net.Listener, shutdownC <-chan struct{}, options *StartOptions) error { defer listener.Close() for { select { @@ -65,22 +72,22 @@ func Serve(logger *logrus.Logger, listener net.Listener, originURL string, shutd if err != nil { return err } - go serveConnection(logger, conn, originURL, headers) + go serveConnection(logger, conn, options) } } } // serveConnection handles connections for the Serve() call -func serveConnection(logger *logrus.Logger, c net.Conn, originURL string, headers http.Header) { +func serveConnection(logger *logrus.Logger, c net.Conn, options *StartOptions) { defer c.Close() - serveStream(logger, originURL, c, headers) + serveStream(logger, c, options) } // serveStream will serve the data over the WebSocket stream -func serveStream(logger *logrus.Logger, originURL string, conn io.ReadWriter, headers http.Header) error { - wsConn, err := createWebsocketStream(originURL, headers) +func serveStream(logger *logrus.Logger, conn io.ReadWriter, options *StartOptions) error { + wsConn, err := createWebsocketStream(options) if err != nil { - logger.WithError(err).Errorf("failed to connect to %s\n", originURL) + logger.WithError(err).Errorf("failed to connect to %s\n", options.OriginURL) return err } defer wsConn.Close() @@ -93,12 +100,12 @@ func serveStream(logger *logrus.Logger, originURL string, conn io.ReadWriter, he // createWebsocketStream will create a WebSocket connection to stream data over // It also handles redirects from Access and will present that flow if // the token is not present on the request -func createWebsocketStream(originURL string, headers http.Header) (*websocket.Conn, error) { - req, err := http.NewRequest(http.MethodGet, originURL, nil) +func createWebsocketStream(options *StartOptions) (*websocket.Conn, error) { + req, err := http.NewRequest(http.MethodGet, options.OriginURL, nil) if err != nil { return nil, err } - req.Header = headers + req.Header = options.Headers wsConn, resp, err := websocket.ClientConnect(req, nil) if err != nil && resp != nil && resp.StatusCode > 300 { @@ -109,11 +116,17 @@ func createWebsocketStream(originURL string, headers http.Header) (*websocket.Co if !strings.Contains(location.String(), "cdn-cgi/access/login") { return nil, errors.New("not an Access redirect") } - req, err := buildAccessRequest(originURL) + req, token, err := buildAccessRequest(options.OriginURL) if err != nil { return nil, err } + if options.ShouldGenCert { + if err := sshgen.GenerateShortLivedCertificate(req.URL, token); err != nil { + return nil, err + } + } + wsConn, _, err = websocket.ClientConnect(req, nil) if err != nil { return nil, err @@ -126,24 +139,24 @@ func createWebsocketStream(originURL string, headers http.Header) (*websocket.Co } // buildAccessRequest builds an HTTP request with the Access token set -func buildAccessRequest(originURL string) (*http.Request, error) { +func buildAccessRequest(originURL string) (*http.Request, string, error) { req, err := http.NewRequest(http.MethodGet, originURL, nil) if err != nil { - return nil, err + return nil, "", err } token, err := token.FetchToken(req.URL) if err != nil { - return nil, err + return nil, "", err } // We need to create a new request as FetchToken will modify req (boo mutable) // as it has to follow redirect on the API and such, so here we init a new one originRequest, err := http.NewRequest(http.MethodGet, originURL, nil) if err != nil { - return nil, err + return nil, "", err } originRequest.Header.Set("cf-access-token", token) - return originRequest, nil + return originRequest, token, nil } diff --git a/carrier/carrier_test.go b/carrier/carrier_test.go index e1171175..60dfed4e 100644 --- a/carrier/carrier_test.go +++ b/carrier/carrier_test.go @@ -48,7 +48,12 @@ func TestStartClient(t *testing.T) { defer ts.Close() buf := newTestStream() - err := StartClient(logger, "http://"+ts.Listener.Addr().String(), buf, nil) + options := &StartOptions{ + OriginURL: "http://" + ts.Listener.Addr().String(), + Headers: nil, + ShouldGenCert: false, + } + err := StartClient(logger, buf, options) assert.NoError(t, err) buf.Write([]byte(message)) @@ -67,9 +72,14 @@ func TestStartServer(t *testing.T) { shutdownC := make(chan struct{}) ts := newTestWebSocketServer() defer ts.Close() + options := &StartOptions{ + OriginURL: "http://" + ts.Listener.Addr().String(), + Headers: nil, + ShouldGenCert: false, + } go func() { - err := Serve(logger, listener, "http://"+ts.Listener.Addr().String(), shutdownC, nil) + err := Serve(logger, listener, shutdownC, options) if err != nil { t.Fatalf("Error running server: %v", err) } diff --git a/cmd/cloudflared/access/carrier.go b/cmd/cloudflared/access/carrier.go index 4061f336..a6dc3ae1 100644 --- a/cmd/cloudflared/access/carrier.go +++ b/cmd/cloudflared/access/carrier.go @@ -17,19 +17,32 @@ import ( // useful for proxying other protocols (like ssh) over websockets // (which you can put Access in front of) func ssh(c *cli.Context) error { - hostname, err := validation.ValidateHostname(c.String("hostname")) - if err != nil || c.String("hostname") == "" { + // get the hostname from the cmdline and error out if its not provided + rawHostName := c.String(sshHostnameFlag) + hostname, err := validation.ValidateHostname(rawHostName) + if err != nil || rawHostName == "" { return cli.ShowCommandHelp(c, "ssh") } - headers := buildRequestHeaders(c.StringSlice("header")) - if c.IsSet("service-token-id") { - headers.Add("CF-Access-Client-Id", c.String("service-token-id")) + originURL := "https://" + hostname + + // get the headers from the cmdline and add them + headers := buildRequestHeaders(c.StringSlice(sshHeaderFlag)) + if c.IsSet(sshTokenIDFlag) { + headers.Add("CF-Access-Client-Id", c.String(sshTokenIDFlag)) } - if c.IsSet("service-token-secret") { - headers.Add("CF-Access-Client-Secret", c.String("service-token-secret")) + if c.IsSet(sshTokenSecretFlag) { + headers.Add("CF-Access-Client-Secret", c.String(sshTokenSecretFlag)) } - if c.NArg() > 0 || c.IsSet("url") { + genCertBool := c.Bool(sshGenCertFlag) + + options := &carrier.StartOptions{ + OriginURL: originURL, + Headers: headers, + ShouldGenCert: genCertBool, + } + + if c.NArg() > 0 || c.IsSet(sshURLFlag) { localForwarder, err := config.ValidateUrl(c) if err != nil { logger.WithError(err).Error("Error validating origin URL") @@ -40,10 +53,10 @@ func ssh(c *cli.Context) error { logger.WithError(err).Error("Error validating origin URL") return errors.Wrap(err, "error validating origin URL") } - return carrier.StartServer(logger, forwarder.Host, "https://"+hostname, shutdownC, headers) + return carrier.StartServer(logger, forwarder.Host, shutdownC, options) } - return carrier.StartClient(logger, "https://"+hostname, &carrier.StdinoutStream{}, headers) + return carrier.StartClient(logger, &carrier.StdinoutStream{}, options) } func buildRequestHeaders(values []string) http.Header { diff --git a/cmd/cloudflared/access/cmd.go b/cmd/cloudflared/access/cmd.go index 9753c719..b1babc46 100644 --- a/cmd/cloudflared/access/cmd.go +++ b/cmd/cloudflared/access/cmd.go @@ -16,6 +16,15 @@ import ( cli "gopkg.in/urfave/cli.v2" ) +const ( + sshHostnameFlag = "hostname" + sshURLFlag = "url" + sshHeaderFlag = "header" + sshTokenIDFlag = "service-token-id" + sshTokenSecretFlag = "service-token-secret" + sshGenCertFlag = "gen-cert" +) + const sentryDSN = "https://56a9c9fa5c364ab28f34b14f35ea0f1b@sentry.io/189878" var ( @@ -93,27 +102,31 @@ func Commands() []*cli.Command { Description: `The ssh subcommand sends data over a proxy to the Cloudflare edge.`, Flags: []cli.Flag{ &cli.StringFlag{ - Name: "hostname", - Usage: "specifics the hostname of your application.", + Name: sshHostnameFlag, + Usage: "specify the hostname of your application.", }, &cli.StringFlag{ - Name: "url", - Usage: "specifics the host:port to forward data to Cloudflare edge.", + Name: sshURLFlag, + Usage: "specify the host:port to forward data to Cloudflare edge.", }, &cli.StringSliceFlag{ - Name: "header", + Name: sshHeaderFlag, Aliases: []string{"H"}, - Usage: "specific additional headers you wish to send.", + Usage: "specify additional headers you wish to send.", }, &cli.StringSliceFlag{ - Name: "service-token-id", + Name: sshTokenIDFlag, Aliases: []string{"id"}, - Usage: "specific an Access service token ID you wish to use.", + Usage: "specify an Access service token ID you wish to use.", }, &cli.StringSliceFlag{ - Name: "service-token-secret", + Name: sshTokenSecretFlag, Aliases: []string{"secret"}, - Usage: "specific an Access service token secret you wish to use.", + Usage: "specify an Access service token secret you wish to use.", + }, + &cli.BoolFlag{ + Name: sshGenCertFlag, + Usage: "specify if you wish to generate short lived certs.", }, }, }, diff --git a/cmd/cloudflared/path/path.go b/cmd/cloudflared/path/path.go new file mode 100644 index 00000000..08cda221 --- /dev/null +++ b/cmd/cloudflared/path/path.go @@ -0,0 +1,30 @@ +package path + +import ( + "fmt" + "net/url" + "os" + "path/filepath" + "strings" + + "github.com/cloudflare/cloudflared/cmd/cloudflared/config" + "github.com/mitchellh/go-homedir" +) + +// GenerateFilePathFromURL will return a filepath for given access application url +func GenerateFilePathFromURL(url *url.URL, suffix string) (string, error) { + configPath, err := homedir.Expand(config.DefaultConfigDirs[0]) + if err != nil { + return "", err + } + ok, err := config.FileExists(configPath) + if !ok && err == nil { + // create config directory if doesn't already exist + err = os.Mkdir(configPath, 0700) + } + if err != nil { + return "", err + } + name := strings.Replace(fmt.Sprintf("%s%s-%s", url.Hostname(), url.EscapedPath(), suffix), "/", "-", -1) + return filepath.Join(configPath, name), nil +} diff --git a/cmd/cloudflared/token/token.go b/cmd/cloudflared/token/token.go index e5649b4e..a7655e4f 100644 --- a/cmd/cloudflared/token/token.go +++ b/cmd/cloudflared/token/token.go @@ -1,20 +1,19 @@ package token import ( - "fmt" "io/ioutil" "net/url" - "os" - "path/filepath" - "strings" "time" - "github.com/cloudflare/cloudflared/cmd/cloudflared/config" + "github.com/cloudflare/cloudflared/cmd/cloudflared/path" "github.com/cloudflare/cloudflared/cmd/cloudflared/transfer" "github.com/cloudflare/cloudflared/log" "github.com/coreos/go-oidc/jose" "github.com/coreos/go-oidc/oidc" - homedir "github.com/mitchellh/go-homedir" +) + +const ( + keyName = "token" ) var logger = log.CreateLogger() @@ -25,7 +24,7 @@ func FetchToken(appURL *url.URL) (string, error) { return token, nil } - path, err := generateFilePathForTokenURL(appURL) + path, err := path.GenerateFilePathFromURL(appURL, keyName) if err != nil { return "", err } @@ -33,8 +32,7 @@ func FetchToken(appURL *url.URL) (string, error) { // this weird parameter is the resource name (token) and the key/value // we want to send to the transfer service. the key is token and the value // is blank (basically just the id generated in the transfer service) - const resourceName, key, value = "token", "token", "" - token, err := transfer.Run(appURL, resourceName, key, value, path, true) + token, err := transfer.Run(appURL, keyName, keyName, "", path, true) if err != nil { return "", err } @@ -44,7 +42,7 @@ func FetchToken(appURL *url.URL) (string, error) { // GetTokenIfExists will return the token from local storage if it exists func GetTokenIfExists(url *url.URL) (string, error) { - path, err := generateFilePathForTokenURL(url) + path, err := path.GenerateFilePathFromURL(url, keyName) if err != nil { return "", err } @@ -68,21 +66,3 @@ func GetTokenIfExists(url *url.URL) (string, error) { } return "", err } - -// generateFilePathForTokenURL will return a filepath for given access application url -func generateFilePathForTokenURL(url *url.URL) (string, error) { - configPath, err := homedir.Expand(config.DefaultConfigDirs[0]) - if err != nil { - return "", err - } - ok, err := config.FileExists(configPath) - if !ok && err == nil { - // create config directory if doesn't already exist - err = os.Mkdir(configPath, 0700) - } - if err != nil { - return "", err - } - name := strings.Replace(fmt.Sprintf("%s%s-token", url.Hostname(), url.EscapedPath()), "/", "-", -1) - return filepath.Join(configPath, name), nil -} diff --git a/sshgen/sshgen.go b/sshgen/sshgen.go new file mode 100644 index 00000000..14d66a3f --- /dev/null +++ b/sshgen/sshgen.go @@ -0,0 +1,163 @@ +package sshgen + +import ( + "bytes" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "crypto/x509" + "encoding/json" + "encoding/pem" + "errors" + "io/ioutil" + "net/http" + "net/url" + "time" + + "github.com/cloudflare/cloudflared/cmd/cloudflared/config" + cfpath "github.com/cloudflare/cloudflared/cmd/cloudflared/path" + "github.com/coreos/go-oidc/jose" + homedir "github.com/mitchellh/go-homedir" + gossh "golang.org/x/crypto/ssh" +) + +const ( + signEndpoint = "/cdn-cgi/access/cert_sign" + keyName = "cf_key" +) + +// signPayload represents the request body sent to the sign handler API +type signPayload struct { + PublicKey string `json:"public_key"` + JWT string `json:"jwt"` + Issuer string `json:"issuer"` +} + +// signResponse represents the response body from the sign handler API +type signResponse struct { + KeyID string `json:"id"` + Certificate string `json:"certificate"` + ExpiresAt time.Time `json:"expires_at"` +} + +// GenerateShortLivedCertificate generates and stores a keypair for short lived certs +func GenerateShortLivedCertificate(appURL *url.URL, token string) error { + fullName, err := cfpath.GenerateFilePathFromURL(appURL, keyName) + if err != nil { + return err + } + + cert, err := handleCertificateGeneration(token, fullName) + if err != nil { + return err + } + + name := fullName + "-cert.pub" + if err := writeKey(name, []byte(cert)); err != nil { + return err + } + + return nil +} + +// handleCertificateGeneration takes a JWT and uses it build a signPayload +// to send to the Sign endpoint with the public key from the keypair it generated +func handleCertificateGeneration(token, fullName string) (string, error) { + if token == "" { + return "", errors.New("invalid token") + } + + jwt, err := jose.ParseJWT(token) + if err != nil { + return "", err + } + + claims, err := jwt.Claims() + if err != nil { + return "", err + } + + issuer, _, err := claims.StringClaim("iss") + if err != nil { + return "", err + } + + pub, err := generateKeyPair(fullName) + if err != nil { + return "", err + } + + buf, err := json.Marshal(&signPayload{ + PublicKey: string(pub), + JWT: token, + Issuer: issuer, + }) + if err != nil { + return "", err + } + + res, err := http.Post(issuer+signEndpoint, "application/json", bytes.NewBuffer(buf)) + if err != nil { + return "", err + } + defer res.Body.Close() + + decoder := json.NewDecoder(res.Body) + var signRes signResponse + if err := decoder.Decode(&signRes); err != nil { + return "", err + } + return signRes.Certificate, err +} + +// generateKeyPair creates a EC keypair (P256) and stores them in the homedir. +// returns the generated public key from the successful keypair generation +func generateKeyPair(fullName string) ([]byte, error) { + pubKeyName := fullName + ".pub" + + exist, err := config.FileExists(pubKeyName) + if err != nil { + return nil, err + } + if exist { + return ioutil.ReadFile(pubKeyName) + } + + key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) + if err != nil { + return nil, err + } + parsed, err := x509.MarshalECPrivateKey(key) + if err != nil { + return nil, err + } + + if err := writeKey(fullName, pem.EncodeToMemory(&pem.Block{ + Type: "EC PRIVATE KEY", + Bytes: parsed, + })); err != nil { + return nil, err + } + + pub, err := gossh.NewPublicKey(&key.PublicKey) + if err != nil { + return nil, err + } + data := gossh.MarshalAuthorizedKey(pub) + + if err := writeKey(pubKeyName, data); err != nil { + return nil, err + } + + return data, nil +} + +// writeKey will write a key to disk in DER format (it's a standard pem key) +func writeKey(filename string, data []byte) error { + filepath, err := homedir.Expand(filename) + if err != nil { + return err + } + + return ioutil.WriteFile(filepath, data, 0600) +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/asm_arm64.s b/vendor/golang.org/x/crypto/internal/chacha20/asm_arm64.s new file mode 100644 index 00000000..b3a16ef7 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/asm_arm64.s @@ -0,0 +1,308 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.11 +// +build !gccgo,!appengine + +#include "textflag.h" + +#define NUM_ROUNDS 10 + +// func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32) +TEXT ·xorKeyStreamVX(SB), NOSPLIT, $0 + MOVD dst+0(FP), R1 + MOVD src+24(FP), R2 + MOVD src_len+32(FP), R3 + MOVD key+48(FP), R4 + MOVD nonce+56(FP), R6 + MOVD counter+64(FP), R7 + + MOVD $·constants(SB), R10 + MOVD $·incRotMatrix(SB), R11 + + MOVW (R7), R20 + + AND $~255, R3, R13 + ADD R2, R13, R12 // R12 for block end + AND $255, R3, R13 +loop: + MOVD $NUM_ROUNDS, R21 + VLD1 (R11), [V30.S4, V31.S4] + + // load contants + // VLD4R (R10), [V0.S4, V1.S4, V2.S4, V3.S4] + WORD $0x4D60E940 + + // load keys + // VLD4R 16(R4), [V4.S4, V5.S4, V6.S4, V7.S4] + WORD $0x4DFFE884 + // VLD4R 16(R4), [V8.S4, V9.S4, V10.S4, V11.S4] + WORD $0x4DFFE888 + SUB $32, R4 + + // load counter + nonce + // VLD1R (R7), [V12.S4] + WORD $0x4D40C8EC + + // VLD3R (R6), [V13.S4, V14.S4, V15.S4] + WORD $0x4D40E8CD + + // update counter + VADD V30.S4, V12.S4, V12.S4 + +chacha: + // V0..V3 += V4..V7 + // V12..V15 <<<= ((V12..V15 XOR V0..V3), 16) + VADD V0.S4, V4.S4, V0.S4 + VADD V1.S4, V5.S4, V1.S4 + VADD V2.S4, V6.S4, V2.S4 + VADD V3.S4, V7.S4, V3.S4 + VEOR V12.B16, V0.B16, V12.B16 + VEOR V13.B16, V1.B16, V13.B16 + VEOR V14.B16, V2.B16, V14.B16 + VEOR V15.B16, V3.B16, V15.B16 + VREV32 V12.H8, V12.H8 + VREV32 V13.H8, V13.H8 + VREV32 V14.H8, V14.H8 + VREV32 V15.H8, V15.H8 + // V8..V11 += V12..V15 + // V4..V7 <<<= ((V4..V7 XOR V8..V11), 12) + VADD V8.S4, V12.S4, V8.S4 + VADD V9.S4, V13.S4, V9.S4 + VADD V10.S4, V14.S4, V10.S4 + VADD V11.S4, V15.S4, V11.S4 + VEOR V8.B16, V4.B16, V16.B16 + VEOR V9.B16, V5.B16, V17.B16 + VEOR V10.B16, V6.B16, V18.B16 + VEOR V11.B16, V7.B16, V19.B16 + VSHL $12, V16.S4, V4.S4 + VSHL $12, V17.S4, V5.S4 + VSHL $12, V18.S4, V6.S4 + VSHL $12, V19.S4, V7.S4 + VSRI $20, V16.S4, V4.S4 + VSRI $20, V17.S4, V5.S4 + VSRI $20, V18.S4, V6.S4 + VSRI $20, V19.S4, V7.S4 + + // V0..V3 += V4..V7 + // V12..V15 <<<= ((V12..V15 XOR V0..V3), 8) + VADD V0.S4, V4.S4, V0.S4 + VADD V1.S4, V5.S4, V1.S4 + VADD V2.S4, V6.S4, V2.S4 + VADD V3.S4, V7.S4, V3.S4 + VEOR V12.B16, V0.B16, V12.B16 + VEOR V13.B16, V1.B16, V13.B16 + VEOR V14.B16, V2.B16, V14.B16 + VEOR V15.B16, V3.B16, V15.B16 + VTBL V31.B16, [V12.B16], V12.B16 + VTBL V31.B16, [V13.B16], V13.B16 + VTBL V31.B16, [V14.B16], V14.B16 + VTBL V31.B16, [V15.B16], V15.B16 + + // V8..V11 += V12..V15 + // V4..V7 <<<= ((V4..V7 XOR V8..V11), 7) + VADD V12.S4, V8.S4, V8.S4 + VADD V13.S4, V9.S4, V9.S4 + VADD V14.S4, V10.S4, V10.S4 + VADD V15.S4, V11.S4, V11.S4 + VEOR V8.B16, V4.B16, V16.B16 + VEOR V9.B16, V5.B16, V17.B16 + VEOR V10.B16, V6.B16, V18.B16 + VEOR V11.B16, V7.B16, V19.B16 + VSHL $7, V16.S4, V4.S4 + VSHL $7, V17.S4, V5.S4 + VSHL $7, V18.S4, V6.S4 + VSHL $7, V19.S4, V7.S4 + VSRI $25, V16.S4, V4.S4 + VSRI $25, V17.S4, V5.S4 + VSRI $25, V18.S4, V6.S4 + VSRI $25, V19.S4, V7.S4 + + // V0..V3 += V5..V7, V4 + // V15,V12-V14 <<<= ((V15,V12-V14 XOR V0..V3), 16) + VADD V0.S4, V5.S4, V0.S4 + VADD V1.S4, V6.S4, V1.S4 + VADD V2.S4, V7.S4, V2.S4 + VADD V3.S4, V4.S4, V3.S4 + VEOR V15.B16, V0.B16, V15.B16 + VEOR V12.B16, V1.B16, V12.B16 + VEOR V13.B16, V2.B16, V13.B16 + VEOR V14.B16, V3.B16, V14.B16 + VREV32 V12.H8, V12.H8 + VREV32 V13.H8, V13.H8 + VREV32 V14.H8, V14.H8 + VREV32 V15.H8, V15.H8 + + // V10 += V15; V5 <<<= ((V10 XOR V5), 12) + // ... + VADD V15.S4, V10.S4, V10.S4 + VADD V12.S4, V11.S4, V11.S4 + VADD V13.S4, V8.S4, V8.S4 + VADD V14.S4, V9.S4, V9.S4 + VEOR V10.B16, V5.B16, V16.B16 + VEOR V11.B16, V6.B16, V17.B16 + VEOR V8.B16, V7.B16, V18.B16 + VEOR V9.B16, V4.B16, V19.B16 + VSHL $12, V16.S4, V5.S4 + VSHL $12, V17.S4, V6.S4 + VSHL $12, V18.S4, V7.S4 + VSHL $12, V19.S4, V4.S4 + VSRI $20, V16.S4, V5.S4 + VSRI $20, V17.S4, V6.S4 + VSRI $20, V18.S4, V7.S4 + VSRI $20, V19.S4, V4.S4 + + // V0 += V5; V15 <<<= ((V0 XOR V15), 8) + // ... + VADD V5.S4, V0.S4, V0.S4 + VADD V6.S4, V1.S4, V1.S4 + VADD V7.S4, V2.S4, V2.S4 + VADD V4.S4, V3.S4, V3.S4 + VEOR V0.B16, V15.B16, V15.B16 + VEOR V1.B16, V12.B16, V12.B16 + VEOR V2.B16, V13.B16, V13.B16 + VEOR V3.B16, V14.B16, V14.B16 + VTBL V31.B16, [V12.B16], V12.B16 + VTBL V31.B16, [V13.B16], V13.B16 + VTBL V31.B16, [V14.B16], V14.B16 + VTBL V31.B16, [V15.B16], V15.B16 + + // V10 += V15; V5 <<<= ((V10 XOR V5), 7) + // ... + VADD V15.S4, V10.S4, V10.S4 + VADD V12.S4, V11.S4, V11.S4 + VADD V13.S4, V8.S4, V8.S4 + VADD V14.S4, V9.S4, V9.S4 + VEOR V10.B16, V5.B16, V16.B16 + VEOR V11.B16, V6.B16, V17.B16 + VEOR V8.B16, V7.B16, V18.B16 + VEOR V9.B16, V4.B16, V19.B16 + VSHL $7, V16.S4, V5.S4 + VSHL $7, V17.S4, V6.S4 + VSHL $7, V18.S4, V7.S4 + VSHL $7, V19.S4, V4.S4 + VSRI $25, V16.S4, V5.S4 + VSRI $25, V17.S4, V6.S4 + VSRI $25, V18.S4, V7.S4 + VSRI $25, V19.S4, V4.S4 + + SUB $1, R21 + CBNZ R21, chacha + + // VLD4R (R10), [V16.S4, V17.S4, V18.S4, V19.S4] + WORD $0x4D60E950 + + // VLD4R 16(R4), [V20.S4, V21.S4, V22.S4, V23.S4] + WORD $0x4DFFE894 + VADD V30.S4, V12.S4, V12.S4 + VADD V16.S4, V0.S4, V0.S4 + VADD V17.S4, V1.S4, V1.S4 + VADD V18.S4, V2.S4, V2.S4 + VADD V19.S4, V3.S4, V3.S4 + // VLD4R 16(R4), [V24.S4, V25.S4, V26.S4, V27.S4] + WORD $0x4DFFE898 + // restore R4 + SUB $32, R4 + + // load counter + nonce + // VLD1R (R7), [V28.S4] + WORD $0x4D40C8FC + // VLD3R (R6), [V29.S4, V30.S4, V31.S4] + WORD $0x4D40E8DD + + VADD V20.S4, V4.S4, V4.S4 + VADD V21.S4, V5.S4, V5.S4 + VADD V22.S4, V6.S4, V6.S4 + VADD V23.S4, V7.S4, V7.S4 + VADD V24.S4, V8.S4, V8.S4 + VADD V25.S4, V9.S4, V9.S4 + VADD V26.S4, V10.S4, V10.S4 + VADD V27.S4, V11.S4, V11.S4 + VADD V28.S4, V12.S4, V12.S4 + VADD V29.S4, V13.S4, V13.S4 + VADD V30.S4, V14.S4, V14.S4 + VADD V31.S4, V15.S4, V15.S4 + + VZIP1 V1.S4, V0.S4, V16.S4 + VZIP2 V1.S4, V0.S4, V17.S4 + VZIP1 V3.S4, V2.S4, V18.S4 + VZIP2 V3.S4, V2.S4, V19.S4 + VZIP1 V5.S4, V4.S4, V20.S4 + VZIP2 V5.S4, V4.S4, V21.S4 + VZIP1 V7.S4, V6.S4, V22.S4 + VZIP2 V7.S4, V6.S4, V23.S4 + VZIP1 V9.S4, V8.S4, V24.S4 + VZIP2 V9.S4, V8.S4, V25.S4 + VZIP1 V11.S4, V10.S4, V26.S4 + VZIP2 V11.S4, V10.S4, V27.S4 + VZIP1 V13.S4, V12.S4, V28.S4 + VZIP2 V13.S4, V12.S4, V29.S4 + VZIP1 V15.S4, V14.S4, V30.S4 + VZIP2 V15.S4, V14.S4, V31.S4 + VZIP1 V18.D2, V16.D2, V0.D2 + VZIP2 V18.D2, V16.D2, V4.D2 + VZIP1 V19.D2, V17.D2, V8.D2 + VZIP2 V19.D2, V17.D2, V12.D2 + VLD1.P 64(R2), [V16.B16, V17.B16, V18.B16, V19.B16] + + VZIP1 V22.D2, V20.D2, V1.D2 + VZIP2 V22.D2, V20.D2, V5.D2 + VZIP1 V23.D2, V21.D2, V9.D2 + VZIP2 V23.D2, V21.D2, V13.D2 + VLD1.P 64(R2), [V20.B16, V21.B16, V22.B16, V23.B16] + VZIP1 V26.D2, V24.D2, V2.D2 + VZIP2 V26.D2, V24.D2, V6.D2 + VZIP1 V27.D2, V25.D2, V10.D2 + VZIP2 V27.D2, V25.D2, V14.D2 + VLD1.P 64(R2), [V24.B16, V25.B16, V26.B16, V27.B16] + VZIP1 V30.D2, V28.D2, V3.D2 + VZIP2 V30.D2, V28.D2, V7.D2 + VZIP1 V31.D2, V29.D2, V11.D2 + VZIP2 V31.D2, V29.D2, V15.D2 + VLD1.P 64(R2), [V28.B16, V29.B16, V30.B16, V31.B16] + VEOR V0.B16, V16.B16, V16.B16 + VEOR V1.B16, V17.B16, V17.B16 + VEOR V2.B16, V18.B16, V18.B16 + VEOR V3.B16, V19.B16, V19.B16 + VST1.P [V16.B16, V17.B16, V18.B16, V19.B16], 64(R1) + VEOR V4.B16, V20.B16, V20.B16 + VEOR V5.B16, V21.B16, V21.B16 + VEOR V6.B16, V22.B16, V22.B16 + VEOR V7.B16, V23.B16, V23.B16 + VST1.P [V20.B16, V21.B16, V22.B16, V23.B16], 64(R1) + VEOR V8.B16, V24.B16, V24.B16 + VEOR V9.B16, V25.B16, V25.B16 + VEOR V10.B16, V26.B16, V26.B16 + VEOR V11.B16, V27.B16, V27.B16 + VST1.P [V24.B16, V25.B16, V26.B16, V27.B16], 64(R1) + VEOR V12.B16, V28.B16, V28.B16 + VEOR V13.B16, V29.B16, V29.B16 + VEOR V14.B16, V30.B16, V30.B16 + VEOR V15.B16, V31.B16, V31.B16 + VST1.P [V28.B16, V29.B16, V30.B16, V31.B16], 64(R1) + + ADD $4, R20 + MOVW R20, (R7) // update counter + + CMP R2, R12 + BGT loop + + RET + + +DATA ·constants+0x00(SB)/4, $0x61707865 +DATA ·constants+0x04(SB)/4, $0x3320646e +DATA ·constants+0x08(SB)/4, $0x79622d32 +DATA ·constants+0x0c(SB)/4, $0x6b206574 +GLOBL ·constants(SB), NOPTR|RODATA, $32 + +DATA ·incRotMatrix+0x00(SB)/4, $0x00000000 +DATA ·incRotMatrix+0x04(SB)/4, $0x00000001 +DATA ·incRotMatrix+0x08(SB)/4, $0x00000002 +DATA ·incRotMatrix+0x0c(SB)/4, $0x00000003 +DATA ·incRotMatrix+0x10(SB)/4, $0x02010003 +DATA ·incRotMatrix+0x14(SB)/4, $0x06050407 +DATA ·incRotMatrix+0x18(SB)/4, $0x0A09080B +DATA ·incRotMatrix+0x1c(SB)/4, $0x0E0D0C0F +GLOBL ·incRotMatrix(SB), NOPTR|RODATA, $32 diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_arm64.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_arm64.go new file mode 100644 index 00000000..ad74e23a --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_arm64.go @@ -0,0 +1,31 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build go1.11 +// +build !gccgo + +package chacha20 + +const ( + haveAsm = true + bufSize = 256 +) + +//go:noescape +func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32) + +func (c *Cipher) xorKeyStreamAsm(dst, src []byte) { + + if len(src) >= bufSize { + xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter) + } + + if len(src)%bufSize != 0 { + i := len(src) - len(src)%bufSize + c.buf = [bufSize]byte{} + copy(c.buf[:], src[i:]) + xorKeyStreamVX(c.buf[:], c.buf[:], &c.key, &c.nonce, &c.counter) + c.len = bufSize - copy(dst[i:], c.buf[:len(src)%bufSize]) + } +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go new file mode 100644 index 00000000..6570847f --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go @@ -0,0 +1,264 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package ChaCha20 implements the core ChaCha20 function as specified +// in https://tools.ietf.org/html/rfc7539#section-2.3. +package chacha20 + +import ( + "crypto/cipher" + "encoding/binary" + + "golang.org/x/crypto/internal/subtle" +) + +// assert that *Cipher implements cipher.Stream +var _ cipher.Stream = (*Cipher)(nil) + +// Cipher is a stateful instance of ChaCha20 using a particular key +// and nonce. A *Cipher implements the cipher.Stream interface. +type Cipher struct { + key [8]uint32 + counter uint32 // incremented after each block + nonce [3]uint32 + buf [bufSize]byte // buffer for unused keystream bytes + len int // number of unused keystream bytes at end of buf +} + +// New creates a new ChaCha20 stream cipher with the given key and nonce. +// The initial counter value is set to 0. +func New(key [8]uint32, nonce [3]uint32) *Cipher { + return &Cipher{key: key, nonce: nonce} +} + +// ChaCha20 constants spelling "expand 32-byte k" +const ( + j0 uint32 = 0x61707865 + j1 uint32 = 0x3320646e + j2 uint32 = 0x79622d32 + j3 uint32 = 0x6b206574 +) + +func quarterRound(a, b, c, d uint32) (uint32, uint32, uint32, uint32) { + a += b + d ^= a + d = (d << 16) | (d >> 16) + c += d + b ^= c + b = (b << 12) | (b >> 20) + a += b + d ^= a + d = (d << 8) | (d >> 24) + c += d + b ^= c + b = (b << 7) | (b >> 25) + return a, b, c, d +} + +// XORKeyStream XORs each byte in the given slice with a byte from the +// cipher's key stream. Dst and src must overlap entirely or not at all. +// +// If len(dst) < len(src), XORKeyStream will panic. It is acceptable +// to pass a dst bigger than src, and in that case, XORKeyStream will +// only update dst[:len(src)] and will not touch the rest of dst. +// +// Multiple calls to XORKeyStream behave as if the concatenation of +// the src buffers was passed in a single run. That is, Cipher +// maintains state and does not reset at each XORKeyStream call. +func (s *Cipher) XORKeyStream(dst, src []byte) { + if len(dst) < len(src) { + panic("chacha20: output smaller than input") + } + if subtle.InexactOverlap(dst[:len(src)], src) { + panic("chacha20: invalid buffer overlap") + } + + // xor src with buffered keystream first + if s.len != 0 { + buf := s.buf[len(s.buf)-s.len:] + if len(src) < len(buf) { + buf = buf[:len(src)] + } + td, ts := dst[:len(buf)], src[:len(buf)] // BCE hint + for i, b := range buf { + td[i] = ts[i] ^ b + } + s.len -= len(buf) + if s.len != 0 { + return + } + s.buf = [len(s.buf)]byte{} // zero the empty buffer + src = src[len(buf):] + dst = dst[len(buf):] + } + + if len(src) == 0 { + return + } + if haveAsm { + if uint64(len(src))+uint64(s.counter)*64 > (1<<38)-64 { + panic("chacha20: counter overflow") + } + s.xorKeyStreamAsm(dst, src) + return + } + + // set up a 64-byte buffer to pad out the final block if needed + // (hoisted out of the main loop to avoid spills) + rem := len(src) % 64 // length of final block + fin := len(src) - rem // index of final block + if rem > 0 { + copy(s.buf[len(s.buf)-64:], src[fin:]) + } + + // pre-calculate most of the first round + s1, s5, s9, s13 := quarterRound(j1, s.key[1], s.key[5], s.nonce[0]) + s2, s6, s10, s14 := quarterRound(j2, s.key[2], s.key[6], s.nonce[1]) + s3, s7, s11, s15 := quarterRound(j3, s.key[3], s.key[7], s.nonce[2]) + + n := len(src) + src, dst = src[:n:n], dst[:n:n] // BCE hint + for i := 0; i < n; i += 64 { + // calculate the remainder of the first round + s0, s4, s8, s12 := quarterRound(j0, s.key[0], s.key[4], s.counter) + + // execute the second round + x0, x5, x10, x15 := quarterRound(s0, s5, s10, s15) + x1, x6, x11, x12 := quarterRound(s1, s6, s11, s12) + x2, x7, x8, x13 := quarterRound(s2, s7, s8, s13) + x3, x4, x9, x14 := quarterRound(s3, s4, s9, s14) + + // execute the remaining 18 rounds + for i := 0; i < 9; i++ { + x0, x4, x8, x12 = quarterRound(x0, x4, x8, x12) + x1, x5, x9, x13 = quarterRound(x1, x5, x9, x13) + x2, x6, x10, x14 = quarterRound(x2, x6, x10, x14) + x3, x7, x11, x15 = quarterRound(x3, x7, x11, x15) + + x0, x5, x10, x15 = quarterRound(x0, x5, x10, x15) + x1, x6, x11, x12 = quarterRound(x1, x6, x11, x12) + x2, x7, x8, x13 = quarterRound(x2, x7, x8, x13) + x3, x4, x9, x14 = quarterRound(x3, x4, x9, x14) + } + + x0 += j0 + x1 += j1 + x2 += j2 + x3 += j3 + + x4 += s.key[0] + x5 += s.key[1] + x6 += s.key[2] + x7 += s.key[3] + x8 += s.key[4] + x9 += s.key[5] + x10 += s.key[6] + x11 += s.key[7] + + x12 += s.counter + x13 += s.nonce[0] + x14 += s.nonce[1] + x15 += s.nonce[2] + + // increment the counter + s.counter += 1 + if s.counter == 0 { + panic("chacha20: counter overflow") + } + + // pad to 64 bytes if needed + in, out := src[i:], dst[i:] + if i == fin { + // src[fin:] has already been copied into s.buf before + // the main loop + in, out = s.buf[len(s.buf)-64:], s.buf[len(s.buf)-64:] + } + in, out = in[:64], out[:64] // BCE hint + + // XOR the key stream with the source and write out the result + xor(out[0:], in[0:], x0) + xor(out[4:], in[4:], x1) + xor(out[8:], in[8:], x2) + xor(out[12:], in[12:], x3) + xor(out[16:], in[16:], x4) + xor(out[20:], in[20:], x5) + xor(out[24:], in[24:], x6) + xor(out[28:], in[28:], x7) + xor(out[32:], in[32:], x8) + xor(out[36:], in[36:], x9) + xor(out[40:], in[40:], x10) + xor(out[44:], in[44:], x11) + xor(out[48:], in[48:], x12) + xor(out[52:], in[52:], x13) + xor(out[56:], in[56:], x14) + xor(out[60:], in[60:], x15) + } + // copy any trailing bytes out of the buffer and into dst + if rem != 0 { + s.len = 64 - rem + copy(dst[fin:], s.buf[len(s.buf)-64:]) + } +} + +// Advance discards bytes in the key stream until the next 64 byte block +// boundary is reached and updates the counter accordingly. If the key +// stream is already at a block boundary no bytes will be discarded and +// the counter will be unchanged. +func (s *Cipher) Advance() { + s.len -= s.len % 64 + if s.len == 0 { + s.buf = [len(s.buf)]byte{} + } +} + +// XORKeyStream crypts bytes from in to out using the given key and counters. +// In and out must overlap entirely or not at all. Counter contains the raw +// ChaCha20 counter bytes (i.e. block counter followed by nonce). +func XORKeyStream(out, in []byte, counter *[16]byte, key *[32]byte) { + s := Cipher{ + key: [8]uint32{ + binary.LittleEndian.Uint32(key[0:4]), + binary.LittleEndian.Uint32(key[4:8]), + binary.LittleEndian.Uint32(key[8:12]), + binary.LittleEndian.Uint32(key[12:16]), + binary.LittleEndian.Uint32(key[16:20]), + binary.LittleEndian.Uint32(key[20:24]), + binary.LittleEndian.Uint32(key[24:28]), + binary.LittleEndian.Uint32(key[28:32]), + }, + nonce: [3]uint32{ + binary.LittleEndian.Uint32(counter[4:8]), + binary.LittleEndian.Uint32(counter[8:12]), + binary.LittleEndian.Uint32(counter[12:16]), + }, + counter: binary.LittleEndian.Uint32(counter[0:4]), + } + s.XORKeyStream(out, in) +} + +// HChaCha20 uses the ChaCha20 core to generate a derived key from a key and a +// nonce. It should only be used as part of the XChaCha20 construction. +func HChaCha20(key *[8]uint32, nonce *[4]uint32) [8]uint32 { + x0, x1, x2, x3 := j0, j1, j2, j3 + x4, x5, x6, x7 := key[0], key[1], key[2], key[3] + x8, x9, x10, x11 := key[4], key[5], key[6], key[7] + x12, x13, x14, x15 := nonce[0], nonce[1], nonce[2], nonce[3] + + for i := 0; i < 10; i++ { + x0, x4, x8, x12 = quarterRound(x0, x4, x8, x12) + x1, x5, x9, x13 = quarterRound(x1, x5, x9, x13) + x2, x6, x10, x14 = quarterRound(x2, x6, x10, x14) + x3, x7, x11, x15 = quarterRound(x3, x7, x11, x15) + + x0, x5, x10, x15 = quarterRound(x0, x5, x10, x15) + x1, x6, x11, x12 = quarterRound(x1, x6, x11, x12) + x2, x7, x8, x13 = quarterRound(x2, x7, x8, x13) + x3, x4, x9, x14 = quarterRound(x3, x4, x9, x14) + } + + var out [8]uint32 + out[0], out[1], out[2], out[3] = x0, x1, x2, x3 + out[4], out[5], out[6], out[7] = x12, x13, x14, x15 + return out +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go new file mode 100644 index 00000000..47eac031 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go @@ -0,0 +1,16 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build !arm64,!s390x arm64,!go1.11 gccgo appengine + +package chacha20 + +const ( + bufSize = 64 + haveAsm = false +) + +func (*Cipher) xorKeyStreamAsm(dst, src []byte) { + panic("not implemented") +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go new file mode 100644 index 00000000..aad645b4 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go @@ -0,0 +1,29 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build s390x,!gccgo,!appengine + +package chacha20 + +import ( + "golang.org/x/sys/cpu" +) + +var haveAsm = cpu.S390X.HasVX + +const bufSize = 256 + +// xorKeyStreamVX is an assembly implementation of XORKeyStream. It must only +// be called when the vector facility is available. +// Implementation in asm_s390x.s. +//go:noescape +func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32, buf *[256]byte, len *int) + +func (c *Cipher) xorKeyStreamAsm(dst, src []byte) { + xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter, &c.buf, &c.len) +} + +// EXRL targets, DO NOT CALL! +func mvcSrcToBuf() +func mvcBufToDst() diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.s b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.s new file mode 100644 index 00000000..57df4044 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.s @@ -0,0 +1,260 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build s390x,!gccgo,!appengine + +#include "go_asm.h" +#include "textflag.h" + +// This is an implementation of the ChaCha20 encryption algorithm as +// specified in RFC 7539. It uses vector instructions to compute +// 4 keystream blocks in parallel (256 bytes) which are then XORed +// with the bytes in the input slice. + +GLOBL ·constants<>(SB), RODATA|NOPTR, $32 +// BSWAP: swap bytes in each 4-byte element +DATA ·constants<>+0x00(SB)/4, $0x03020100 +DATA ·constants<>+0x04(SB)/4, $0x07060504 +DATA ·constants<>+0x08(SB)/4, $0x0b0a0908 +DATA ·constants<>+0x0c(SB)/4, $0x0f0e0d0c +// J0: [j0, j1, j2, j3] +DATA ·constants<>+0x10(SB)/4, $0x61707865 +DATA ·constants<>+0x14(SB)/4, $0x3320646e +DATA ·constants<>+0x18(SB)/4, $0x79622d32 +DATA ·constants<>+0x1c(SB)/4, $0x6b206574 + +// EXRL targets: +TEXT ·mvcSrcToBuf(SB), NOFRAME|NOSPLIT, $0 + MVC $1, (R1), (R8) + RET + +TEXT ·mvcBufToDst(SB), NOFRAME|NOSPLIT, $0 + MVC $1, (R8), (R9) + RET + +#define BSWAP V5 +#define J0 V6 +#define KEY0 V7 +#define KEY1 V8 +#define NONCE V9 +#define CTR V10 +#define M0 V11 +#define M1 V12 +#define M2 V13 +#define M3 V14 +#define INC V15 +#define X0 V16 +#define X1 V17 +#define X2 V18 +#define X3 V19 +#define X4 V20 +#define X5 V21 +#define X6 V22 +#define X7 V23 +#define X8 V24 +#define X9 V25 +#define X10 V26 +#define X11 V27 +#define X12 V28 +#define X13 V29 +#define X14 V30 +#define X15 V31 + +#define NUM_ROUNDS 20 + +#define ROUND4(a0, a1, a2, a3, b0, b1, b2, b3, c0, c1, c2, c3, d0, d1, d2, d3) \ + VAF a1, a0, a0 \ + VAF b1, b0, b0 \ + VAF c1, c0, c0 \ + VAF d1, d0, d0 \ + VX a0, a2, a2 \ + VX b0, b2, b2 \ + VX c0, c2, c2 \ + VX d0, d2, d2 \ + VERLLF $16, a2, a2 \ + VERLLF $16, b2, b2 \ + VERLLF $16, c2, c2 \ + VERLLF $16, d2, d2 \ + VAF a2, a3, a3 \ + VAF b2, b3, b3 \ + VAF c2, c3, c3 \ + VAF d2, d3, d3 \ + VX a3, a1, a1 \ + VX b3, b1, b1 \ + VX c3, c1, c1 \ + VX d3, d1, d1 \ + VERLLF $12, a1, a1 \ + VERLLF $12, b1, b1 \ + VERLLF $12, c1, c1 \ + VERLLF $12, d1, d1 \ + VAF a1, a0, a0 \ + VAF b1, b0, b0 \ + VAF c1, c0, c0 \ + VAF d1, d0, d0 \ + VX a0, a2, a2 \ + VX b0, b2, b2 \ + VX c0, c2, c2 \ + VX d0, d2, d2 \ + VERLLF $8, a2, a2 \ + VERLLF $8, b2, b2 \ + VERLLF $8, c2, c2 \ + VERLLF $8, d2, d2 \ + VAF a2, a3, a3 \ + VAF b2, b3, b3 \ + VAF c2, c3, c3 \ + VAF d2, d3, d3 \ + VX a3, a1, a1 \ + VX b3, b1, b1 \ + VX c3, c1, c1 \ + VX d3, d1, d1 \ + VERLLF $7, a1, a1 \ + VERLLF $7, b1, b1 \ + VERLLF $7, c1, c1 \ + VERLLF $7, d1, d1 + +#define PERMUTE(mask, v0, v1, v2, v3) \ + VPERM v0, v0, mask, v0 \ + VPERM v1, v1, mask, v1 \ + VPERM v2, v2, mask, v2 \ + VPERM v3, v3, mask, v3 + +#define ADDV(x, v0, v1, v2, v3) \ + VAF x, v0, v0 \ + VAF x, v1, v1 \ + VAF x, v2, v2 \ + VAF x, v3, v3 + +#define XORV(off, dst, src, v0, v1, v2, v3) \ + VLM off(src), M0, M3 \ + PERMUTE(BSWAP, v0, v1, v2, v3) \ + VX v0, M0, M0 \ + VX v1, M1, M1 \ + VX v2, M2, M2 \ + VX v3, M3, M3 \ + VSTM M0, M3, off(dst) + +#define SHUFFLE(a, b, c, d, t, u, v, w) \ + VMRHF a, c, t \ // t = {a[0], c[0], a[1], c[1]} + VMRHF b, d, u \ // u = {b[0], d[0], b[1], d[1]} + VMRLF a, c, v \ // v = {a[2], c[2], a[3], c[3]} + VMRLF b, d, w \ // w = {b[2], d[2], b[3], d[3]} + VMRHF t, u, a \ // a = {a[0], b[0], c[0], d[0]} + VMRLF t, u, b \ // b = {a[1], b[1], c[1], d[1]} + VMRHF v, w, c \ // c = {a[2], b[2], c[2], d[2]} + VMRLF v, w, d // d = {a[3], b[3], c[3], d[3]} + +// func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32, buf *[256]byte, len *int) +TEXT ·xorKeyStreamVX(SB), NOSPLIT, $0 + MOVD $·constants<>(SB), R1 + MOVD dst+0(FP), R2 // R2=&dst[0] + LMG src+24(FP), R3, R4 // R3=&src[0] R4=len(src) + MOVD key+48(FP), R5 // R5=key + MOVD nonce+56(FP), R6 // R6=nonce + MOVD counter+64(FP), R7 // R7=counter + MOVD buf+72(FP), R8 // R8=buf + MOVD len+80(FP), R9 // R9=len + + // load BSWAP and J0 + VLM (R1), BSWAP, J0 + + // set up tail buffer + ADD $-1, R4, R12 + MOVBZ R12, R12 + CMPUBEQ R12, $255, aligned + MOVD R4, R1 + AND $~255, R1 + MOVD $(R3)(R1*1), R1 + EXRL $·mvcSrcToBuf(SB), R12 + MOVD $255, R0 + SUB R12, R0 + MOVD R0, (R9) // update len + +aligned: + // setup + MOVD $95, R0 + VLM (R5), KEY0, KEY1 + VLL R0, (R6), NONCE + VZERO M0 + VLEIB $7, $32, M0 + VSRLB M0, NONCE, NONCE + + // initialize counter values + VLREPF (R7), CTR + VZERO INC + VLEIF $1, $1, INC + VLEIF $2, $2, INC + VLEIF $3, $3, INC + VAF INC, CTR, CTR + VREPIF $4, INC + +chacha: + VREPF $0, J0, X0 + VREPF $1, J0, X1 + VREPF $2, J0, X2 + VREPF $3, J0, X3 + VREPF $0, KEY0, X4 + VREPF $1, KEY0, X5 + VREPF $2, KEY0, X6 + VREPF $3, KEY0, X7 + VREPF $0, KEY1, X8 + VREPF $1, KEY1, X9 + VREPF $2, KEY1, X10 + VREPF $3, KEY1, X11 + VLR CTR, X12 + VREPF $1, NONCE, X13 + VREPF $2, NONCE, X14 + VREPF $3, NONCE, X15 + + MOVD $(NUM_ROUNDS/2), R1 + +loop: + ROUND4(X0, X4, X12, X8, X1, X5, X13, X9, X2, X6, X14, X10, X3, X7, X15, X11) + ROUND4(X0, X5, X15, X10, X1, X6, X12, X11, X2, X7, X13, X8, X3, X4, X14, X9) + + ADD $-1, R1 + BNE loop + + // decrement length + ADD $-256, R4 + BLT tail + +continue: + // rearrange vectors + SHUFFLE(X0, X1, X2, X3, M0, M1, M2, M3) + ADDV(J0, X0, X1, X2, X3) + SHUFFLE(X4, X5, X6, X7, M0, M1, M2, M3) + ADDV(KEY0, X4, X5, X6, X7) + SHUFFLE(X8, X9, X10, X11, M0, M1, M2, M3) + ADDV(KEY1, X8, X9, X10, X11) + VAF CTR, X12, X12 + SHUFFLE(X12, X13, X14, X15, M0, M1, M2, M3) + ADDV(NONCE, X12, X13, X14, X15) + + // increment counters + VAF INC, CTR, CTR + + // xor keystream with plaintext + XORV(0*64, R2, R3, X0, X4, X8, X12) + XORV(1*64, R2, R3, X1, X5, X9, X13) + XORV(2*64, R2, R3, X2, X6, X10, X14) + XORV(3*64, R2, R3, X3, X7, X11, X15) + + // increment pointers + MOVD $256(R2), R2 + MOVD $256(R3), R3 + + CMPBNE R4, $0, chacha + CMPUBEQ R12, $255, return + EXRL $·mvcBufToDst(SB), R12 // len was updated during setup + +return: + VSTEF $0, CTR, (R7) + RET + +tail: + MOVD R2, R9 + MOVD R8, R2 + MOVD R8, R3 + MOVD $0, R4 + JMP continue diff --git a/vendor/golang.org/x/crypto/internal/chacha20/xor.go b/vendor/golang.org/x/crypto/internal/chacha20/xor.go new file mode 100644 index 00000000..9c5ba0b3 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/xor.go @@ -0,0 +1,43 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found src the LICENSE file. + +package chacha20 + +import ( + "runtime" +) + +// Platforms that have fast unaligned 32-bit little endian accesses. +const unaligned = runtime.GOARCH == "386" || + runtime.GOARCH == "amd64" || + runtime.GOARCH == "arm64" || + runtime.GOARCH == "ppc64le" || + runtime.GOARCH == "s390x" + +// xor reads a little endian uint32 from src, XORs it with u and +// places the result in little endian byte order in dst. +func xor(dst, src []byte, u uint32) { + _, _ = src[3], dst[3] // eliminate bounds checks + if unaligned { + // The compiler should optimize this code into + // 32-bit unaligned little endian loads and stores. + // TODO: delete once the compiler does a reliably + // good job with the generic code below. + // See issue #25111 for more details. + v := uint32(src[0]) + v |= uint32(src[1]) << 8 + v |= uint32(src[2]) << 16 + v |= uint32(src[3]) << 24 + v ^= u + dst[0] = byte(v) + dst[1] = byte(v >> 8) + dst[2] = byte(v >> 16) + dst[3] = byte(v >> 24) + } else { + dst[0] = src[0] ^ byte(u) + dst[1] = src[1] ^ byte(u>>8) + dst[2] = src[2] ^ byte(u>>16) + dst[3] = src[3] ^ byte(u>>24) + } +} diff --git a/vendor/golang.org/x/crypto/ssh/buffer.go b/vendor/golang.org/x/crypto/ssh/buffer.go new file mode 100644 index 00000000..1ab07d07 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/buffer.go @@ -0,0 +1,97 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "io" + "sync" +) + +// buffer provides a linked list buffer for data exchange +// between producer and consumer. Theoretically the buffer is +// of unlimited capacity as it does no allocation of its own. +type buffer struct { + // protects concurrent access to head, tail and closed + *sync.Cond + + head *element // the buffer that will be read first + tail *element // the buffer that will be read last + + closed bool +} + +// An element represents a single link in a linked list. +type element struct { + buf []byte + next *element +} + +// newBuffer returns an empty buffer that is not closed. +func newBuffer() *buffer { + e := new(element) + b := &buffer{ + Cond: newCond(), + head: e, + tail: e, + } + return b +} + +// write makes buf available for Read to receive. +// buf must not be modified after the call to write. +func (b *buffer) write(buf []byte) { + b.Cond.L.Lock() + e := &element{buf: buf} + b.tail.next = e + b.tail = e + b.Cond.Signal() + b.Cond.L.Unlock() +} + +// eof closes the buffer. Reads from the buffer once all +// the data has been consumed will receive io.EOF. +func (b *buffer) eof() { + b.Cond.L.Lock() + b.closed = true + b.Cond.Signal() + b.Cond.L.Unlock() +} + +// Read reads data from the internal buffer in buf. Reads will block +// if no data is available, or until the buffer is closed. +func (b *buffer) Read(buf []byte) (n int, err error) { + b.Cond.L.Lock() + defer b.Cond.L.Unlock() + + for len(buf) > 0 { + // if there is data in b.head, copy it + if len(b.head.buf) > 0 { + r := copy(buf, b.head.buf) + buf, b.head.buf = buf[r:], b.head.buf[r:] + n += r + continue + } + // if there is a next buffer, make it the head + if len(b.head.buf) == 0 && b.head != b.tail { + b.head = b.head.next + continue + } + + // if at least one byte has been copied, return + if n > 0 { + break + } + + // if nothing was read, and there is nothing outstanding + // check to see if the buffer is closed. + if b.closed { + err = io.EOF + break + } + // out of buffers, wait for producer + b.Cond.Wait() + } + return +} diff --git a/vendor/golang.org/x/crypto/ssh/certs.go b/vendor/golang.org/x/crypto/ssh/certs.go new file mode 100644 index 00000000..00ed9923 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/certs.go @@ -0,0 +1,535 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "net" + "sort" + "time" +) + +// These constants from [PROTOCOL.certkeys] represent the algorithm names +// for certificate types supported by this package. +const ( + CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com" + CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com" + CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com" + CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com" + CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com" + CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com" +) + +// Certificate types distinguish between host and user +// certificates. The values can be set in the CertType field of +// Certificate. +const ( + UserCert = 1 + HostCert = 2 +) + +// Signature represents a cryptographic signature. +type Signature struct { + Format string + Blob []byte +} + +// CertTimeInfinity can be used for OpenSSHCertV01.ValidBefore to indicate that +// a certificate does not expire. +const CertTimeInfinity = 1<<64 - 1 + +// An Certificate represents an OpenSSH certificate as defined in +// [PROTOCOL.certkeys]?rev=1.8. The Certificate type implements the +// PublicKey interface, so it can be unmarshaled using +// ParsePublicKey. +type Certificate struct { + Nonce []byte + Key PublicKey + Serial uint64 + CertType uint32 + KeyId string + ValidPrincipals []string + ValidAfter uint64 + ValidBefore uint64 + Permissions + Reserved []byte + SignatureKey PublicKey + Signature *Signature +} + +// genericCertData holds the key-independent part of the certificate data. +// Overall, certificates contain an nonce, public key fields and +// key-independent fields. +type genericCertData struct { + Serial uint64 + CertType uint32 + KeyId string + ValidPrincipals []byte + ValidAfter uint64 + ValidBefore uint64 + CriticalOptions []byte + Extensions []byte + Reserved []byte + SignatureKey []byte + Signature []byte +} + +func marshalStringList(namelist []string) []byte { + var to []byte + for _, name := range namelist { + s := struct{ N string }{name} + to = append(to, Marshal(&s)...) + } + return to +} + +type optionsTuple struct { + Key string + Value []byte +} + +type optionsTupleValue struct { + Value string +} + +// serialize a map of critical options or extensions +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty string value +func marshalTuples(tups map[string]string) []byte { + keys := make([]string, 0, len(tups)) + for key := range tups { + keys = append(keys, key) + } + sort.Strings(keys) + + var ret []byte + for _, key := range keys { + s := optionsTuple{Key: key} + if value := tups[key]; len(value) > 0 { + s.Value = Marshal(&optionsTupleValue{value}) + } + ret = append(ret, Marshal(&s)...) + } + return ret +} + +// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation, +// we need two length prefixes for a non-empty option value +func parseTuples(in []byte) (map[string]string, error) { + tups := map[string]string{} + var lastKey string + var haveLastKey bool + + for len(in) > 0 { + var key, val, extra []byte + var ok bool + + if key, in, ok = parseString(in); !ok { + return nil, errShortRead + } + keyStr := string(key) + // according to [PROTOCOL.certkeys], the names must be in + // lexical order. + if haveLastKey && keyStr <= lastKey { + return nil, fmt.Errorf("ssh: certificate options are not in lexical order") + } + lastKey, haveLastKey = keyStr, true + // the next field is a data field, which if non-empty has a string embedded + if val, in, ok = parseString(in); !ok { + return nil, errShortRead + } + if len(val) > 0 { + val, extra, ok = parseString(val) + if !ok { + return nil, errShortRead + } + if len(extra) > 0 { + return nil, fmt.Errorf("ssh: unexpected trailing data after certificate option value") + } + tups[keyStr] = string(val) + } else { + tups[keyStr] = "" + } + } + return tups, nil +} + +func parseCert(in []byte, privAlgo string) (*Certificate, error) { + nonce, rest, ok := parseString(in) + if !ok { + return nil, errShortRead + } + + key, rest, err := parsePubKey(rest, privAlgo) + if err != nil { + return nil, err + } + + var g genericCertData + if err := Unmarshal(rest, &g); err != nil { + return nil, err + } + + c := &Certificate{ + Nonce: nonce, + Key: key, + Serial: g.Serial, + CertType: g.CertType, + KeyId: g.KeyId, + ValidAfter: g.ValidAfter, + ValidBefore: g.ValidBefore, + } + + for principals := g.ValidPrincipals; len(principals) > 0; { + principal, rest, ok := parseString(principals) + if !ok { + return nil, errShortRead + } + c.ValidPrincipals = append(c.ValidPrincipals, string(principal)) + principals = rest + } + + c.CriticalOptions, err = parseTuples(g.CriticalOptions) + if err != nil { + return nil, err + } + c.Extensions, err = parseTuples(g.Extensions) + if err != nil { + return nil, err + } + c.Reserved = g.Reserved + k, err := ParsePublicKey(g.SignatureKey) + if err != nil { + return nil, err + } + + c.SignatureKey = k + c.Signature, rest, ok = parseSignatureBody(g.Signature) + if !ok || len(rest) > 0 { + return nil, errors.New("ssh: signature parse error") + } + + return c, nil +} + +type openSSHCertSigner struct { + pub *Certificate + signer Signer +} + +type algorithmOpenSSHCertSigner struct { + *openSSHCertSigner + algorithmSigner AlgorithmSigner +} + +// NewCertSigner returns a Signer that signs with the given Certificate, whose +// private key is held by signer. It returns an error if the public key in cert +// doesn't match the key used by signer. +func NewCertSigner(cert *Certificate, signer Signer) (Signer, error) { + if bytes.Compare(cert.Key.Marshal(), signer.PublicKey().Marshal()) != 0 { + return nil, errors.New("ssh: signer and cert have different public key") + } + + if algorithmSigner, ok := signer.(AlgorithmSigner); ok { + return &algorithmOpenSSHCertSigner{ + &openSSHCertSigner{cert, signer}, algorithmSigner}, nil + } else { + return &openSSHCertSigner{cert, signer}, nil + } +} + +func (s *openSSHCertSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + return s.signer.Sign(rand, data) +} + +func (s *openSSHCertSigner) PublicKey() PublicKey { + return s.pub +} + +func (s *algorithmOpenSSHCertSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + return s.algorithmSigner.SignWithAlgorithm(rand, data, algorithm) +} + +const sourceAddressCriticalOption = "source-address" + +// CertChecker does the work of verifying a certificate. Its methods +// can be plugged into ClientConfig.HostKeyCallback and +// ServerConfig.PublicKeyCallback. For the CertChecker to work, +// minimally, the IsAuthority callback should be set. +type CertChecker struct { + // SupportedCriticalOptions lists the CriticalOptions that the + // server application layer understands. These are only used + // for user certificates. + SupportedCriticalOptions []string + + // IsUserAuthority should return true if the key is recognized as an + // authority for the given user certificate. This allows for + // certificates to be signed by other certificates. This must be set + // if this CertChecker will be checking user certificates. + IsUserAuthority func(auth PublicKey) bool + + // IsHostAuthority should report whether the key is recognized as + // an authority for this host. This allows for certificates to be + // signed by other keys, and for those other keys to only be valid + // signers for particular hostnames. This must be set if this + // CertChecker will be checking host certificates. + IsHostAuthority func(auth PublicKey, address string) bool + + // Clock is used for verifying time stamps. If nil, time.Now + // is used. + Clock func() time.Time + + // UserKeyFallback is called when CertChecker.Authenticate encounters a + // public key that is not a certificate. It must implement validation + // of user keys or else, if nil, all such keys are rejected. + UserKeyFallback func(conn ConnMetadata, key PublicKey) (*Permissions, error) + + // HostKeyFallback is called when CertChecker.CheckHostKey encounters a + // public key that is not a certificate. It must implement host key + // validation or else, if nil, all such keys are rejected. + HostKeyFallback HostKeyCallback + + // IsRevoked is called for each certificate so that revocation checking + // can be implemented. It should return true if the given certificate + // is revoked and false otherwise. If nil, no certificates are + // considered to have been revoked. + IsRevoked func(cert *Certificate) bool +} + +// CheckHostKey checks a host key certificate. This method can be +// plugged into ClientConfig.HostKeyCallback. +func (c *CertChecker) CheckHostKey(addr string, remote net.Addr, key PublicKey) error { + cert, ok := key.(*Certificate) + if !ok { + if c.HostKeyFallback != nil { + return c.HostKeyFallback(addr, remote, key) + } + return errors.New("ssh: non-certificate host key") + } + if cert.CertType != HostCert { + return fmt.Errorf("ssh: certificate presented as a host key has type %d", cert.CertType) + } + if !c.IsHostAuthority(cert.SignatureKey, addr) { + return fmt.Errorf("ssh: no authorities for hostname: %v", addr) + } + + hostname, _, err := net.SplitHostPort(addr) + if err != nil { + return err + } + + // Pass hostname only as principal for host certificates (consistent with OpenSSH) + return c.CheckCert(hostname, cert) +} + +// Authenticate checks a user certificate. Authenticate can be used as +// a value for ServerConfig.PublicKeyCallback. +func (c *CertChecker) Authenticate(conn ConnMetadata, pubKey PublicKey) (*Permissions, error) { + cert, ok := pubKey.(*Certificate) + if !ok { + if c.UserKeyFallback != nil { + return c.UserKeyFallback(conn, pubKey) + } + return nil, errors.New("ssh: normal key pairs not accepted") + } + + if cert.CertType != UserCert { + return nil, fmt.Errorf("ssh: cert has type %d", cert.CertType) + } + if !c.IsUserAuthority(cert.SignatureKey) { + return nil, fmt.Errorf("ssh: certificate signed by unrecognized authority") + } + + if err := c.CheckCert(conn.User(), cert); err != nil { + return nil, err + } + + return &cert.Permissions, nil +} + +// CheckCert checks CriticalOptions, ValidPrincipals, revocation, timestamp and +// the signature of the certificate. +func (c *CertChecker) CheckCert(principal string, cert *Certificate) error { + if c.IsRevoked != nil && c.IsRevoked(cert) { + return fmt.Errorf("ssh: certificate serial %d revoked", cert.Serial) + } + + for opt := range cert.CriticalOptions { + // sourceAddressCriticalOption will be enforced by + // serverAuthenticate + if opt == sourceAddressCriticalOption { + continue + } + + found := false + for _, supp := range c.SupportedCriticalOptions { + if supp == opt { + found = true + break + } + } + if !found { + return fmt.Errorf("ssh: unsupported critical option %q in certificate", opt) + } + } + + if len(cert.ValidPrincipals) > 0 { + // By default, certs are valid for all users/hosts. + found := false + for _, p := range cert.ValidPrincipals { + if p == principal { + found = true + break + } + } + if !found { + return fmt.Errorf("ssh: principal %q not in the set of valid principals for given certificate: %q", principal, cert.ValidPrincipals) + } + } + + clock := c.Clock + if clock == nil { + clock = time.Now + } + + unixNow := clock().Unix() + if after := int64(cert.ValidAfter); after < 0 || unixNow < int64(cert.ValidAfter) { + return fmt.Errorf("ssh: cert is not yet valid") + } + if before := int64(cert.ValidBefore); cert.ValidBefore != uint64(CertTimeInfinity) && (unixNow >= before || before < 0) { + return fmt.Errorf("ssh: cert has expired") + } + if err := cert.SignatureKey.Verify(cert.bytesForSigning(), cert.Signature); err != nil { + return fmt.Errorf("ssh: certificate signature does not verify") + } + + return nil +} + +// SignCert sets c.SignatureKey to the authority's public key and stores a +// Signature, by authority, in the certificate. +func (c *Certificate) SignCert(rand io.Reader, authority Signer) error { + c.Nonce = make([]byte, 32) + if _, err := io.ReadFull(rand, c.Nonce); err != nil { + return err + } + c.SignatureKey = authority.PublicKey() + + sig, err := authority.Sign(rand, c.bytesForSigning()) + if err != nil { + return err + } + c.Signature = sig + return nil +} + +var certAlgoNames = map[string]string{ + KeyAlgoRSA: CertAlgoRSAv01, + KeyAlgoDSA: CertAlgoDSAv01, + KeyAlgoECDSA256: CertAlgoECDSA256v01, + KeyAlgoECDSA384: CertAlgoECDSA384v01, + KeyAlgoECDSA521: CertAlgoECDSA521v01, + KeyAlgoED25519: CertAlgoED25519v01, +} + +// certToPrivAlgo returns the underlying algorithm for a certificate algorithm. +// Panics if a non-certificate algorithm is passed. +func certToPrivAlgo(algo string) string { + for privAlgo, pubAlgo := range certAlgoNames { + if pubAlgo == algo { + return privAlgo + } + } + panic("unknown cert algorithm") +} + +func (cert *Certificate) bytesForSigning() []byte { + c2 := *cert + c2.Signature = nil + out := c2.Marshal() + // Drop trailing signature length. + return out[:len(out)-4] +} + +// Marshal serializes c into OpenSSH's wire format. It is part of the +// PublicKey interface. +func (c *Certificate) Marshal() []byte { + generic := genericCertData{ + Serial: c.Serial, + CertType: c.CertType, + KeyId: c.KeyId, + ValidPrincipals: marshalStringList(c.ValidPrincipals), + ValidAfter: uint64(c.ValidAfter), + ValidBefore: uint64(c.ValidBefore), + CriticalOptions: marshalTuples(c.CriticalOptions), + Extensions: marshalTuples(c.Extensions), + Reserved: c.Reserved, + SignatureKey: c.SignatureKey.Marshal(), + } + if c.Signature != nil { + generic.Signature = Marshal(c.Signature) + } + genericBytes := Marshal(&generic) + keyBytes := c.Key.Marshal() + _, keyBytes, _ = parseString(keyBytes) + prefix := Marshal(&struct { + Name string + Nonce []byte + Key []byte `ssh:"rest"` + }{c.Type(), c.Nonce, keyBytes}) + + result := make([]byte, 0, len(prefix)+len(genericBytes)) + result = append(result, prefix...) + result = append(result, genericBytes...) + return result +} + +// Type returns the key name. It is part of the PublicKey interface. +func (c *Certificate) Type() string { + algo, ok := certAlgoNames[c.Key.Type()] + if !ok { + panic("unknown cert key type " + c.Key.Type()) + } + return algo +} + +// Verify verifies a signature against the certificate's public +// key. It is part of the PublicKey interface. +func (c *Certificate) Verify(data []byte, sig *Signature) error { + return c.Key.Verify(data, sig) +} + +func parseSignatureBody(in []byte) (out *Signature, rest []byte, ok bool) { + format, in, ok := parseString(in) + if !ok { + return + } + + out = &Signature{ + Format: string(format), + } + + if out.Blob, in, ok = parseString(in); !ok { + return + } + + return out, in, ok +} + +func parseSignature(in []byte) (out *Signature, rest []byte, ok bool) { + sigBytes, rest, ok := parseString(in) + if !ok { + return + } + + out, trailing, ok := parseSignatureBody(sigBytes) + if !ok || len(trailing) > 0 { + return nil, nil, false + } + return +} diff --git a/vendor/golang.org/x/crypto/ssh/channel.go b/vendor/golang.org/x/crypto/ssh/channel.go new file mode 100644 index 00000000..c0834c00 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/channel.go @@ -0,0 +1,633 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "encoding/binary" + "errors" + "fmt" + "io" + "log" + "sync" +) + +const ( + minPacketLength = 9 + // channelMaxPacket contains the maximum number of bytes that will be + // sent in a single packet. As per RFC 4253, section 6.1, 32k is also + // the minimum. + channelMaxPacket = 1 << 15 + // We follow OpenSSH here. + channelWindowSize = 64 * channelMaxPacket +) + +// NewChannel represents an incoming request to a channel. It must either be +// accepted for use by calling Accept, or rejected by calling Reject. +type NewChannel interface { + // Accept accepts the channel creation request. It returns the Channel + // and a Go channel containing SSH requests. The Go channel must be + // serviced otherwise the Channel will hang. + Accept() (Channel, <-chan *Request, error) + + // Reject rejects the channel creation request. After calling + // this, no other methods on the Channel may be called. + Reject(reason RejectionReason, message string) error + + // ChannelType returns the type of the channel, as supplied by the + // client. + ChannelType() string + + // ExtraData returns the arbitrary payload for this channel, as supplied + // by the client. This data is specific to the channel type. + ExtraData() []byte +} + +// A Channel is an ordered, reliable, flow-controlled, duplex stream +// that is multiplexed over an SSH connection. +type Channel interface { + // Read reads up to len(data) bytes from the channel. + Read(data []byte) (int, error) + + // Write writes len(data) bytes to the channel. + Write(data []byte) (int, error) + + // Close signals end of channel use. No data may be sent after this + // call. + Close() error + + // CloseWrite signals the end of sending in-band + // data. Requests may still be sent, and the other side may + // still send data + CloseWrite() error + + // SendRequest sends a channel request. If wantReply is true, + // it will wait for a reply and return the result as a + // boolean, otherwise the return value will be false. Channel + // requests are out-of-band messages so they may be sent even + // if the data stream is closed or blocked by flow control. + // If the channel is closed before a reply is returned, io.EOF + // is returned. + SendRequest(name string, wantReply bool, payload []byte) (bool, error) + + // Stderr returns an io.ReadWriter that writes to this channel + // with the extended data type set to stderr. Stderr may + // safely be read and written from a different goroutine than + // Read and Write respectively. + Stderr() io.ReadWriter +} + +// Request is a request sent outside of the normal stream of +// data. Requests can either be specific to an SSH channel, or they +// can be global. +type Request struct { + Type string + WantReply bool + Payload []byte + + ch *channel + mux *mux +} + +// Reply sends a response to a request. It must be called for all requests +// where WantReply is true and is a no-op otherwise. The payload argument is +// ignored for replies to channel-specific requests. +func (r *Request) Reply(ok bool, payload []byte) error { + if !r.WantReply { + return nil + } + + if r.ch == nil { + return r.mux.ackRequest(ok, payload) + } + + return r.ch.ackRequest(ok) +} + +// RejectionReason is an enumeration used when rejecting channel creation +// requests. See RFC 4254, section 5.1. +type RejectionReason uint32 + +const ( + Prohibited RejectionReason = iota + 1 + ConnectionFailed + UnknownChannelType + ResourceShortage +) + +// String converts the rejection reason to human readable form. +func (r RejectionReason) String() string { + switch r { + case Prohibited: + return "administratively prohibited" + case ConnectionFailed: + return "connect failed" + case UnknownChannelType: + return "unknown channel type" + case ResourceShortage: + return "resource shortage" + } + return fmt.Sprintf("unknown reason %d", int(r)) +} + +func min(a uint32, b int) uint32 { + if a < uint32(b) { + return a + } + return uint32(b) +} + +type channelDirection uint8 + +const ( + channelInbound channelDirection = iota + channelOutbound +) + +// channel is an implementation of the Channel interface that works +// with the mux class. +type channel struct { + // R/O after creation + chanType string + extraData []byte + localId, remoteId uint32 + + // maxIncomingPayload and maxRemotePayload are the maximum + // payload sizes of normal and extended data packets for + // receiving and sending, respectively. The wire packet will + // be 9 or 13 bytes larger (excluding encryption overhead). + maxIncomingPayload uint32 + maxRemotePayload uint32 + + mux *mux + + // decided is set to true if an accept or reject message has been sent + // (for outbound channels) or received (for inbound channels). + decided bool + + // direction contains either channelOutbound, for channels created + // locally, or channelInbound, for channels created by the peer. + direction channelDirection + + // Pending internal channel messages. + msg chan interface{} + + // Since requests have no ID, there can be only one request + // with WantReply=true outstanding. This lock is held by a + // goroutine that has such an outgoing request pending. + sentRequestMu sync.Mutex + + incomingRequests chan *Request + + sentEOF bool + + // thread-safe data + remoteWin window + pending *buffer + extPending *buffer + + // windowMu protects myWindow, the flow-control window. + windowMu sync.Mutex + myWindow uint32 + + // writeMu serializes calls to mux.conn.writePacket() and + // protects sentClose and packetPool. This mutex must be + // different from windowMu, as writePacket can block if there + // is a key exchange pending. + writeMu sync.Mutex + sentClose bool + + // packetPool has a buffer for each extended channel ID to + // save allocations during writes. + packetPool map[uint32][]byte +} + +// writePacket sends a packet. If the packet is a channel close, it updates +// sentClose. This method takes the lock c.writeMu. +func (ch *channel) writePacket(packet []byte) error { + ch.writeMu.Lock() + if ch.sentClose { + ch.writeMu.Unlock() + return io.EOF + } + ch.sentClose = (packet[0] == msgChannelClose) + err := ch.mux.conn.writePacket(packet) + ch.writeMu.Unlock() + return err +} + +func (ch *channel) sendMessage(msg interface{}) error { + if debugMux { + log.Printf("send(%d): %#v", ch.mux.chanList.offset, msg) + } + + p := Marshal(msg) + binary.BigEndian.PutUint32(p[1:], ch.remoteId) + return ch.writePacket(p) +} + +// WriteExtended writes data to a specific extended stream. These streams are +// used, for example, for stderr. +func (ch *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) { + if ch.sentEOF { + return 0, io.EOF + } + // 1 byte message type, 4 bytes remoteId, 4 bytes data length + opCode := byte(msgChannelData) + headerLength := uint32(9) + if extendedCode > 0 { + headerLength += 4 + opCode = msgChannelExtendedData + } + + ch.writeMu.Lock() + packet := ch.packetPool[extendedCode] + // We don't remove the buffer from packetPool, so + // WriteExtended calls from different goroutines will be + // flagged as errors by the race detector. + ch.writeMu.Unlock() + + for len(data) > 0 { + space := min(ch.maxRemotePayload, len(data)) + if space, err = ch.remoteWin.reserve(space); err != nil { + return n, err + } + if want := headerLength + space; uint32(cap(packet)) < want { + packet = make([]byte, want) + } else { + packet = packet[:want] + } + + todo := data[:space] + + packet[0] = opCode + binary.BigEndian.PutUint32(packet[1:], ch.remoteId) + if extendedCode > 0 { + binary.BigEndian.PutUint32(packet[5:], uint32(extendedCode)) + } + binary.BigEndian.PutUint32(packet[headerLength-4:], uint32(len(todo))) + copy(packet[headerLength:], todo) + if err = ch.writePacket(packet); err != nil { + return n, err + } + + n += len(todo) + data = data[len(todo):] + } + + ch.writeMu.Lock() + ch.packetPool[extendedCode] = packet + ch.writeMu.Unlock() + + return n, err +} + +func (ch *channel) handleData(packet []byte) error { + headerLen := 9 + isExtendedData := packet[0] == msgChannelExtendedData + if isExtendedData { + headerLen = 13 + } + if len(packet) < headerLen { + // malformed data packet + return parseError(packet[0]) + } + + var extended uint32 + if isExtendedData { + extended = binary.BigEndian.Uint32(packet[5:]) + } + + length := binary.BigEndian.Uint32(packet[headerLen-4 : headerLen]) + if length == 0 { + return nil + } + if length > ch.maxIncomingPayload { + // TODO(hanwen): should send Disconnect? + return errors.New("ssh: incoming packet exceeds maximum payload size") + } + + data := packet[headerLen:] + if length != uint32(len(data)) { + return errors.New("ssh: wrong packet length") + } + + ch.windowMu.Lock() + if ch.myWindow < length { + ch.windowMu.Unlock() + // TODO(hanwen): should send Disconnect with reason? + return errors.New("ssh: remote side wrote too much") + } + ch.myWindow -= length + ch.windowMu.Unlock() + + if extended == 1 { + ch.extPending.write(data) + } else if extended > 0 { + // discard other extended data. + } else { + ch.pending.write(data) + } + return nil +} + +func (c *channel) adjustWindow(n uint32) error { + c.windowMu.Lock() + // Since myWindow is managed on our side, and can never exceed + // the initial window setting, we don't worry about overflow. + c.myWindow += uint32(n) + c.windowMu.Unlock() + return c.sendMessage(windowAdjustMsg{ + AdditionalBytes: uint32(n), + }) +} + +func (c *channel) ReadExtended(data []byte, extended uint32) (n int, err error) { + switch extended { + case 1: + n, err = c.extPending.Read(data) + case 0: + n, err = c.pending.Read(data) + default: + return 0, fmt.Errorf("ssh: extended code %d unimplemented", extended) + } + + if n > 0 { + err = c.adjustWindow(uint32(n)) + // sendWindowAdjust can return io.EOF if the remote + // peer has closed the connection, however we want to + // defer forwarding io.EOF to the caller of Read until + // the buffer has been drained. + if n > 0 && err == io.EOF { + err = nil + } + } + + return n, err +} + +func (c *channel) close() { + c.pending.eof() + c.extPending.eof() + close(c.msg) + close(c.incomingRequests) + c.writeMu.Lock() + // This is not necessary for a normal channel teardown, but if + // there was another error, it is. + c.sentClose = true + c.writeMu.Unlock() + // Unblock writers. + c.remoteWin.close() +} + +// responseMessageReceived is called when a success or failure message is +// received on a channel to check that such a message is reasonable for the +// given channel. +func (ch *channel) responseMessageReceived() error { + if ch.direction == channelInbound { + return errors.New("ssh: channel response message received on inbound channel") + } + if ch.decided { + return errors.New("ssh: duplicate response received for channel") + } + ch.decided = true + return nil +} + +func (ch *channel) handlePacket(packet []byte) error { + switch packet[0] { + case msgChannelData, msgChannelExtendedData: + return ch.handleData(packet) + case msgChannelClose: + ch.sendMessage(channelCloseMsg{PeersID: ch.remoteId}) + ch.mux.chanList.remove(ch.localId) + ch.close() + return nil + case msgChannelEOF: + // RFC 4254 is mute on how EOF affects dataExt messages but + // it is logical to signal EOF at the same time. + ch.extPending.eof() + ch.pending.eof() + return nil + } + + decoded, err := decode(packet) + if err != nil { + return err + } + + switch msg := decoded.(type) { + case *channelOpenFailureMsg: + if err := ch.responseMessageReceived(); err != nil { + return err + } + ch.mux.chanList.remove(msg.PeersID) + ch.msg <- msg + case *channelOpenConfirmMsg: + if err := ch.responseMessageReceived(); err != nil { + return err + } + if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 { + return fmt.Errorf("ssh: invalid MaxPacketSize %d from peer", msg.MaxPacketSize) + } + ch.remoteId = msg.MyID + ch.maxRemotePayload = msg.MaxPacketSize + ch.remoteWin.add(msg.MyWindow) + ch.msg <- msg + case *windowAdjustMsg: + if !ch.remoteWin.add(msg.AdditionalBytes) { + return fmt.Errorf("ssh: invalid window update for %d bytes", msg.AdditionalBytes) + } + case *channelRequestMsg: + req := Request{ + Type: msg.Request, + WantReply: msg.WantReply, + Payload: msg.RequestSpecificData, + ch: ch, + } + + ch.incomingRequests <- &req + default: + ch.msg <- msg + } + return nil +} + +func (m *mux) newChannel(chanType string, direction channelDirection, extraData []byte) *channel { + ch := &channel{ + remoteWin: window{Cond: newCond()}, + myWindow: channelWindowSize, + pending: newBuffer(), + extPending: newBuffer(), + direction: direction, + incomingRequests: make(chan *Request, chanSize), + msg: make(chan interface{}, chanSize), + chanType: chanType, + extraData: extraData, + mux: m, + packetPool: make(map[uint32][]byte), + } + ch.localId = m.chanList.add(ch) + return ch +} + +var errUndecided = errors.New("ssh: must Accept or Reject channel") +var errDecidedAlready = errors.New("ssh: can call Accept or Reject only once") + +type extChannel struct { + code uint32 + ch *channel +} + +func (e *extChannel) Write(data []byte) (n int, err error) { + return e.ch.WriteExtended(data, e.code) +} + +func (e *extChannel) Read(data []byte) (n int, err error) { + return e.ch.ReadExtended(data, e.code) +} + +func (ch *channel) Accept() (Channel, <-chan *Request, error) { + if ch.decided { + return nil, nil, errDecidedAlready + } + ch.maxIncomingPayload = channelMaxPacket + confirm := channelOpenConfirmMsg{ + PeersID: ch.remoteId, + MyID: ch.localId, + MyWindow: ch.myWindow, + MaxPacketSize: ch.maxIncomingPayload, + } + ch.decided = true + if err := ch.sendMessage(confirm); err != nil { + return nil, nil, err + } + + return ch, ch.incomingRequests, nil +} + +func (ch *channel) Reject(reason RejectionReason, message string) error { + if ch.decided { + return errDecidedAlready + } + reject := channelOpenFailureMsg{ + PeersID: ch.remoteId, + Reason: reason, + Message: message, + Language: "en", + } + ch.decided = true + return ch.sendMessage(reject) +} + +func (ch *channel) Read(data []byte) (int, error) { + if !ch.decided { + return 0, errUndecided + } + return ch.ReadExtended(data, 0) +} + +func (ch *channel) Write(data []byte) (int, error) { + if !ch.decided { + return 0, errUndecided + } + return ch.WriteExtended(data, 0) +} + +func (ch *channel) CloseWrite() error { + if !ch.decided { + return errUndecided + } + ch.sentEOF = true + return ch.sendMessage(channelEOFMsg{ + PeersID: ch.remoteId}) +} + +func (ch *channel) Close() error { + if !ch.decided { + return errUndecided + } + + return ch.sendMessage(channelCloseMsg{ + PeersID: ch.remoteId}) +} + +// Extended returns an io.ReadWriter that sends and receives data on the given, +// SSH extended stream. Such streams are used, for example, for stderr. +func (ch *channel) Extended(code uint32) io.ReadWriter { + if !ch.decided { + return nil + } + return &extChannel{code, ch} +} + +func (ch *channel) Stderr() io.ReadWriter { + return ch.Extended(1) +} + +func (ch *channel) SendRequest(name string, wantReply bool, payload []byte) (bool, error) { + if !ch.decided { + return false, errUndecided + } + + if wantReply { + ch.sentRequestMu.Lock() + defer ch.sentRequestMu.Unlock() + } + + msg := channelRequestMsg{ + PeersID: ch.remoteId, + Request: name, + WantReply: wantReply, + RequestSpecificData: payload, + } + + if err := ch.sendMessage(msg); err != nil { + return false, err + } + + if wantReply { + m, ok := (<-ch.msg) + if !ok { + return false, io.EOF + } + switch m.(type) { + case *channelRequestFailureMsg: + return false, nil + case *channelRequestSuccessMsg: + return true, nil + default: + return false, fmt.Errorf("ssh: unexpected response to channel request: %#v", m) + } + } + + return false, nil +} + +// ackRequest either sends an ack or nack to the channel request. +func (ch *channel) ackRequest(ok bool) error { + if !ch.decided { + return errUndecided + } + + var msg interface{} + if !ok { + msg = channelRequestFailureMsg{ + PeersID: ch.remoteId, + } + } else { + msg = channelRequestSuccessMsg{ + PeersID: ch.remoteId, + } + } + return ch.sendMessage(msg) +} + +func (ch *channel) ChannelType() string { + return ch.chanType +} + +func (ch *channel) ExtraData() []byte { + return ch.extraData +} diff --git a/vendor/golang.org/x/crypto/ssh/cipher.go b/vendor/golang.org/x/crypto/ssh/cipher.go new file mode 100644 index 00000000..a65a923b --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/cipher.go @@ -0,0 +1,770 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto/aes" + "crypto/cipher" + "crypto/des" + "crypto/rc4" + "crypto/subtle" + "encoding/binary" + "errors" + "fmt" + "hash" + "io" + "io/ioutil" + "math/bits" + + "golang.org/x/crypto/internal/chacha20" + "golang.org/x/crypto/poly1305" +) + +const ( + packetSizeMultiple = 16 // TODO(huin) this should be determined by the cipher. + + // RFC 4253 section 6.1 defines a minimum packet size of 32768 that implementations + // MUST be able to process (plus a few more kilobytes for padding and mac). The RFC + // indicates implementations SHOULD be able to handle larger packet sizes, but then + // waffles on about reasonable limits. + // + // OpenSSH caps their maxPacket at 256kB so we choose to do + // the same. maxPacket is also used to ensure that uint32 + // length fields do not overflow, so it should remain well + // below 4G. + maxPacket = 256 * 1024 +) + +// noneCipher implements cipher.Stream and provides no encryption. It is used +// by the transport before the first key-exchange. +type noneCipher struct{} + +func (c noneCipher) XORKeyStream(dst, src []byte) { + copy(dst, src) +} + +func newAESCTR(key, iv []byte) (cipher.Stream, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + return cipher.NewCTR(c, iv), nil +} + +func newRC4(key, iv []byte) (cipher.Stream, error) { + return rc4.NewCipher(key) +} + +type cipherMode struct { + keySize int + ivSize int + create func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) +} + +func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + return func(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + stream, err := createFunc(key, iv) + if err != nil { + return nil, err + } + + var streamDump []byte + if skip > 0 { + streamDump = make([]byte, 512) + } + + for remainingToDump := skip; remainingToDump > 0; { + dumpThisTime := remainingToDump + if dumpThisTime > len(streamDump) { + dumpThisTime = len(streamDump) + } + stream.XORKeyStream(streamDump[:dumpThisTime], streamDump[:dumpThisTime]) + remainingToDump -= dumpThisTime + } + + mac := macModes[algs.MAC].new(macKey) + return &streamPacketCipher{ + mac: mac, + etm: macModes[algs.MAC].etm, + macResult: make([]byte, mac.Size()), + cipher: stream, + }, nil + } +} + +// cipherModes documents properties of supported ciphers. Ciphers not included +// are not supported and will not be negotiated, even if explicitly requested in +// ClientConfig.Crypto.Ciphers. +var cipherModes = map[string]*cipherMode{ + // Ciphers from RFC4344, which introduced many CTR-based ciphers. Algorithms + // are defined in the order specified in the RFC. + "aes128-ctr": {16, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + "aes192-ctr": {24, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + "aes256-ctr": {32, aes.BlockSize, streamCipherMode(0, newAESCTR)}, + + // Ciphers from RFC4345, which introduces security-improved arcfour ciphers. + // They are defined in the order specified in the RFC. + "arcfour128": {16, 0, streamCipherMode(1536, newRC4)}, + "arcfour256": {32, 0, streamCipherMode(1536, newRC4)}, + + // Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol. + // Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and + // RC4) has problems with weak keys, and should be used with caution." + // RFC4345 introduces improved versions of Arcfour. + "arcfour": {16, 0, streamCipherMode(0, newRC4)}, + + // AEAD ciphers + gcmCipherID: {16, 12, newGCMCipher}, + chacha20Poly1305ID: {64, 0, newChaCha20Cipher}, + + // CBC mode is insecure and so is not included in the default config. + // (See http://www.isg.rhul.ac.uk/~kp/SandPfinal.pdf). If absolutely + // needed, it's possible to specify a custom Config to enable it. + // You should expect that an active attacker can recover plaintext if + // you do. + aes128cbcID: {16, aes.BlockSize, newAESCBCCipher}, + + // 3des-cbc is insecure and is not included in the default + // config. + tripledescbcID: {24, des.BlockSize, newTripleDESCBCCipher}, +} + +// prefixLen is the length of the packet prefix that contains the packet length +// and number of padding bytes. +const prefixLen = 5 + +// streamPacketCipher is a packetCipher using a stream cipher. +type streamPacketCipher struct { + mac hash.Hash + cipher cipher.Stream + etm bool + + // The following members are to avoid per-packet allocations. + prefix [prefixLen]byte + seqNumBytes [4]byte + padding [2 * packetSizeMultiple]byte + packetData []byte + macResult []byte +} + +// readCipherPacket reads and decrypt a single packet from the reader argument. +func (s *streamPacketCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + if _, err := io.ReadFull(r, s.prefix[:]); err != nil { + return nil, err + } + + var encryptedPaddingLength [1]byte + if s.mac != nil && s.etm { + copy(encryptedPaddingLength[:], s.prefix[4:5]) + s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5]) + } else { + s.cipher.XORKeyStream(s.prefix[:], s.prefix[:]) + } + + length := binary.BigEndian.Uint32(s.prefix[0:4]) + paddingLength := uint32(s.prefix[4]) + + var macSize uint32 + if s.mac != nil { + s.mac.Reset() + binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum) + s.mac.Write(s.seqNumBytes[:]) + if s.etm { + s.mac.Write(s.prefix[:4]) + s.mac.Write(encryptedPaddingLength[:]) + } else { + s.mac.Write(s.prefix[:]) + } + macSize = uint32(s.mac.Size()) + } + + if length <= paddingLength+1 { + return nil, errors.New("ssh: invalid packet length, packet too small") + } + + if length > maxPacket { + return nil, errors.New("ssh: invalid packet length, packet too large") + } + + // the maxPacket check above ensures that length-1+macSize + // does not overflow. + if uint32(cap(s.packetData)) < length-1+macSize { + s.packetData = make([]byte, length-1+macSize) + } else { + s.packetData = s.packetData[:length-1+macSize] + } + + if _, err := io.ReadFull(r, s.packetData); err != nil { + return nil, err + } + mac := s.packetData[length-1:] + data := s.packetData[:length-1] + + if s.mac != nil && s.etm { + s.mac.Write(data) + } + + s.cipher.XORKeyStream(data, data) + + if s.mac != nil { + if !s.etm { + s.mac.Write(data) + } + s.macResult = s.mac.Sum(s.macResult[:0]) + if subtle.ConstantTimeCompare(s.macResult, mac) != 1 { + return nil, errors.New("ssh: MAC failure") + } + } + + return s.packetData[:length-paddingLength-1], nil +} + +// writeCipherPacket encrypts and sends a packet of data to the writer argument +func (s *streamPacketCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + if len(packet) > maxPacket { + return errors.New("ssh: packet too large") + } + + aadlen := 0 + if s.mac != nil && s.etm { + // packet length is not encrypted for EtM modes + aadlen = 4 + } + + paddingLength := packetSizeMultiple - (prefixLen+len(packet)-aadlen)%packetSizeMultiple + if paddingLength < 4 { + paddingLength += packetSizeMultiple + } + + length := len(packet) + 1 + paddingLength + binary.BigEndian.PutUint32(s.prefix[:], uint32(length)) + s.prefix[4] = byte(paddingLength) + padding := s.padding[:paddingLength] + if _, err := io.ReadFull(rand, padding); err != nil { + return err + } + + if s.mac != nil { + s.mac.Reset() + binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum) + s.mac.Write(s.seqNumBytes[:]) + + if s.etm { + // For EtM algorithms, the packet length must stay unencrypted, + // but the following data (padding length) must be encrypted + s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5]) + } + + s.mac.Write(s.prefix[:]) + + if !s.etm { + // For non-EtM algorithms, the algorithm is applied on unencrypted data + s.mac.Write(packet) + s.mac.Write(padding) + } + } + + if !(s.mac != nil && s.etm) { + // For EtM algorithms, the padding length has already been encrypted + // and the packet length must remain unencrypted + s.cipher.XORKeyStream(s.prefix[:], s.prefix[:]) + } + + s.cipher.XORKeyStream(packet, packet) + s.cipher.XORKeyStream(padding, padding) + + if s.mac != nil && s.etm { + // For EtM algorithms, packet and padding must be encrypted + s.mac.Write(packet) + s.mac.Write(padding) + } + + if _, err := w.Write(s.prefix[:]); err != nil { + return err + } + if _, err := w.Write(packet); err != nil { + return err + } + if _, err := w.Write(padding); err != nil { + return err + } + + if s.mac != nil { + s.macResult = s.mac.Sum(s.macResult[:0]) + if _, err := w.Write(s.macResult); err != nil { + return err + } + } + + return nil +} + +type gcmCipher struct { + aead cipher.AEAD + prefix [4]byte + iv []byte + buf []byte +} + +func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + aead, err := cipher.NewGCM(c) + if err != nil { + return nil, err + } + + return &gcmCipher{ + aead: aead, + iv: iv, + }, nil +} + +const gcmTagSize = 16 + +func (c *gcmCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + // Pad out to multiple of 16 bytes. This is different from the + // stream cipher because that encrypts the length too. + padding := byte(packetSizeMultiple - (1+len(packet))%packetSizeMultiple) + if padding < 4 { + padding += packetSizeMultiple + } + + length := uint32(len(packet) + int(padding) + 1) + binary.BigEndian.PutUint32(c.prefix[:], length) + if _, err := w.Write(c.prefix[:]); err != nil { + return err + } + + if cap(c.buf) < int(length) { + c.buf = make([]byte, length) + } else { + c.buf = c.buf[:length] + } + + c.buf[0] = padding + copy(c.buf[1:], packet) + if _, err := io.ReadFull(rand, c.buf[1+len(packet):]); err != nil { + return err + } + c.buf = c.aead.Seal(c.buf[:0], c.iv, c.buf, c.prefix[:]) + if _, err := w.Write(c.buf); err != nil { + return err + } + c.incIV() + + return nil +} + +func (c *gcmCipher) incIV() { + for i := 4 + 7; i >= 4; i-- { + c.iv[i]++ + if c.iv[i] != 0 { + break + } + } +} + +func (c *gcmCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + if _, err := io.ReadFull(r, c.prefix[:]); err != nil { + return nil, err + } + length := binary.BigEndian.Uint32(c.prefix[:]) + if length > maxPacket { + return nil, errors.New("ssh: max packet length exceeded") + } + + if cap(c.buf) < int(length+gcmTagSize) { + c.buf = make([]byte, length+gcmTagSize) + } else { + c.buf = c.buf[:length+gcmTagSize] + } + + if _, err := io.ReadFull(r, c.buf); err != nil { + return nil, err + } + + plain, err := c.aead.Open(c.buf[:0], c.iv, c.buf, c.prefix[:]) + if err != nil { + return nil, err + } + c.incIV() + + padding := plain[0] + if padding < 4 { + // padding is a byte, so it automatically satisfies + // the maximum size, which is 255. + return nil, fmt.Errorf("ssh: illegal padding %d", padding) + } + + if int(padding+1) >= len(plain) { + return nil, fmt.Errorf("ssh: padding %d too large", padding) + } + plain = plain[1 : length-uint32(padding)] + return plain, nil +} + +// cbcCipher implements aes128-cbc cipher defined in RFC 4253 section 6.1 +type cbcCipher struct { + mac hash.Hash + macSize uint32 + decrypter cipher.BlockMode + encrypter cipher.BlockMode + + // The following members are to avoid per-packet allocations. + seqNumBytes [4]byte + packetData []byte + macResult []byte + + // Amount of data we should still read to hide which + // verification error triggered. + oracleCamouflage uint32 +} + +func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + cbc := &cbcCipher{ + mac: macModes[algs.MAC].new(macKey), + decrypter: cipher.NewCBCDecrypter(c, iv), + encrypter: cipher.NewCBCEncrypter(c, iv), + packetData: make([]byte, 1024), + } + if cbc.mac != nil { + cbc.macSize = uint32(cbc.mac.Size()) + } + + return cbc, nil +} + +func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + c, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + cbc, err := newCBCCipher(c, key, iv, macKey, algs) + if err != nil { + return nil, err + } + + return cbc, nil +} + +func newTripleDESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) { + c, err := des.NewTripleDESCipher(key) + if err != nil { + return nil, err + } + + cbc, err := newCBCCipher(c, key, iv, macKey, algs) + if err != nil { + return nil, err + } + + return cbc, nil +} + +func maxUInt32(a, b int) uint32 { + if a > b { + return uint32(a) + } + return uint32(b) +} + +const ( + cbcMinPacketSizeMultiple = 8 + cbcMinPacketSize = 16 + cbcMinPaddingSize = 4 +) + +// cbcError represents a verification error that may leak information. +type cbcError string + +func (e cbcError) Error() string { return string(e) } + +func (c *cbcCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + p, err := c.readCipherPacketLeaky(seqNum, r) + if err != nil { + if _, ok := err.(cbcError); ok { + // Verification error: read a fixed amount of + // data, to make distinguishing between + // failing MAC and failing length check more + // difficult. + io.CopyN(ioutil.Discard, r, int64(c.oracleCamouflage)) + } + } + return p, err +} + +func (c *cbcCipher) readCipherPacketLeaky(seqNum uint32, r io.Reader) ([]byte, error) { + blockSize := c.decrypter.BlockSize() + + // Read the header, which will include some of the subsequent data in the + // case of block ciphers - this is copied back to the payload later. + // How many bytes of payload/padding will be read with this first read. + firstBlockLength := uint32((prefixLen + blockSize - 1) / blockSize * blockSize) + firstBlock := c.packetData[:firstBlockLength] + if _, err := io.ReadFull(r, firstBlock); err != nil { + return nil, err + } + + c.oracleCamouflage = maxPacket + 4 + c.macSize - firstBlockLength + + c.decrypter.CryptBlocks(firstBlock, firstBlock) + length := binary.BigEndian.Uint32(firstBlock[:4]) + if length > maxPacket { + return nil, cbcError("ssh: packet too large") + } + if length+4 < maxUInt32(cbcMinPacketSize, blockSize) { + // The minimum size of a packet is 16 (or the cipher block size, whichever + // is larger) bytes. + return nil, cbcError("ssh: packet too small") + } + // The length of the packet (including the length field but not the MAC) must + // be a multiple of the block size or 8, whichever is larger. + if (length+4)%maxUInt32(cbcMinPacketSizeMultiple, blockSize) != 0 { + return nil, cbcError("ssh: invalid packet length multiple") + } + + paddingLength := uint32(firstBlock[4]) + if paddingLength < cbcMinPaddingSize || length <= paddingLength+1 { + return nil, cbcError("ssh: invalid packet length") + } + + // Positions within the c.packetData buffer: + macStart := 4 + length + paddingStart := macStart - paddingLength + + // Entire packet size, starting before length, ending at end of mac. + entirePacketSize := macStart + c.macSize + + // Ensure c.packetData is large enough for the entire packet data. + if uint32(cap(c.packetData)) < entirePacketSize { + // Still need to upsize and copy, but this should be rare at runtime, only + // on upsizing the packetData buffer. + c.packetData = make([]byte, entirePacketSize) + copy(c.packetData, firstBlock) + } else { + c.packetData = c.packetData[:entirePacketSize] + } + + n, err := io.ReadFull(r, c.packetData[firstBlockLength:]) + if err != nil { + return nil, err + } + c.oracleCamouflage -= uint32(n) + + remainingCrypted := c.packetData[firstBlockLength:macStart] + c.decrypter.CryptBlocks(remainingCrypted, remainingCrypted) + + mac := c.packetData[macStart:] + if c.mac != nil { + c.mac.Reset() + binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum) + c.mac.Write(c.seqNumBytes[:]) + c.mac.Write(c.packetData[:macStart]) + c.macResult = c.mac.Sum(c.macResult[:0]) + if subtle.ConstantTimeCompare(c.macResult, mac) != 1 { + return nil, cbcError("ssh: MAC failure") + } + } + + return c.packetData[prefixLen:paddingStart], nil +} + +func (c *cbcCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error { + effectiveBlockSize := maxUInt32(cbcMinPacketSizeMultiple, c.encrypter.BlockSize()) + + // Length of encrypted portion of the packet (header, payload, padding). + // Enforce minimum padding and packet size. + encLength := maxUInt32(prefixLen+len(packet)+cbcMinPaddingSize, cbcMinPaddingSize) + // Enforce block size. + encLength = (encLength + effectiveBlockSize - 1) / effectiveBlockSize * effectiveBlockSize + + length := encLength - 4 + paddingLength := int(length) - (1 + len(packet)) + + // Overall buffer contains: header, payload, padding, mac. + // Space for the MAC is reserved in the capacity but not the slice length. + bufferSize := encLength + c.macSize + if uint32(cap(c.packetData)) < bufferSize { + c.packetData = make([]byte, encLength, bufferSize) + } else { + c.packetData = c.packetData[:encLength] + } + + p := c.packetData + + // Packet header. + binary.BigEndian.PutUint32(p, length) + p = p[4:] + p[0] = byte(paddingLength) + + // Payload. + p = p[1:] + copy(p, packet) + + // Padding. + p = p[len(packet):] + if _, err := io.ReadFull(rand, p); err != nil { + return err + } + + if c.mac != nil { + c.mac.Reset() + binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum) + c.mac.Write(c.seqNumBytes[:]) + c.mac.Write(c.packetData) + // The MAC is now appended into the capacity reserved for it earlier. + c.packetData = c.mac.Sum(c.packetData) + } + + c.encrypter.CryptBlocks(c.packetData[:encLength], c.packetData[:encLength]) + + if _, err := w.Write(c.packetData); err != nil { + return err + } + + return nil +} + +const chacha20Poly1305ID = "chacha20-poly1305@openssh.com" + +// chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com +// AEAD, which is described here: +// +// https://tools.ietf.org/html/draft-josefsson-ssh-chacha20-poly1305-openssh-00 +// +// the methods here also implement padding, which RFC4253 Section 6 +// also requires of stream ciphers. +type chacha20Poly1305Cipher struct { + lengthKey [8]uint32 + contentKey [8]uint32 + buf []byte +} + +func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) { + if len(key) != 64 { + panic(len(key)) + } + + c := &chacha20Poly1305Cipher{ + buf: make([]byte, 256), + } + + for i := range c.contentKey { + c.contentKey[i] = binary.LittleEndian.Uint32(key[i*4 : (i+1)*4]) + } + for i := range c.lengthKey { + c.lengthKey[i] = binary.LittleEndian.Uint32(key[(i+8)*4 : (i+9)*4]) + } + return c, nil +} + +func (c *chacha20Poly1305Cipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) { + nonce := [3]uint32{0, 0, bits.ReverseBytes32(seqNum)} + s := chacha20.New(c.contentKey, nonce) + var polyKey [32]byte + s.XORKeyStream(polyKey[:], polyKey[:]) + s.Advance() // skip next 32 bytes + + encryptedLength := c.buf[:4] + if _, err := io.ReadFull(r, encryptedLength); err != nil { + return nil, err + } + + var lenBytes [4]byte + chacha20.New(c.lengthKey, nonce).XORKeyStream(lenBytes[:], encryptedLength) + + length := binary.BigEndian.Uint32(lenBytes[:]) + if length > maxPacket { + return nil, errors.New("ssh: invalid packet length, packet too large") + } + + contentEnd := 4 + length + packetEnd := contentEnd + poly1305.TagSize + if uint32(cap(c.buf)) < packetEnd { + c.buf = make([]byte, packetEnd) + copy(c.buf[:], encryptedLength) + } else { + c.buf = c.buf[:packetEnd] + } + + if _, err := io.ReadFull(r, c.buf[4:packetEnd]); err != nil { + return nil, err + } + + var mac [poly1305.TagSize]byte + copy(mac[:], c.buf[contentEnd:packetEnd]) + if !poly1305.Verify(&mac, c.buf[:contentEnd], &polyKey) { + return nil, errors.New("ssh: MAC failure") + } + + plain := c.buf[4:contentEnd] + s.XORKeyStream(plain, plain) + + padding := plain[0] + if padding < 4 { + // padding is a byte, so it automatically satisfies + // the maximum size, which is 255. + return nil, fmt.Errorf("ssh: illegal padding %d", padding) + } + + if int(padding)+1 >= len(plain) { + return nil, fmt.Errorf("ssh: padding %d too large", padding) + } + + plain = plain[1 : len(plain)-int(padding)] + + return plain, nil +} + +func (c *chacha20Poly1305Cipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, payload []byte) error { + nonce := [3]uint32{0, 0, bits.ReverseBytes32(seqNum)} + s := chacha20.New(c.contentKey, nonce) + var polyKey [32]byte + s.XORKeyStream(polyKey[:], polyKey[:]) + s.Advance() // skip next 32 bytes + + // There is no blocksize, so fall back to multiple of 8 byte + // padding, as described in RFC 4253, Sec 6. + const packetSizeMultiple = 8 + + padding := packetSizeMultiple - (1+len(payload))%packetSizeMultiple + if padding < 4 { + padding += packetSizeMultiple + } + + // size (4 bytes), padding (1), payload, padding, tag. + totalLength := 4 + 1 + len(payload) + padding + poly1305.TagSize + if cap(c.buf) < totalLength { + c.buf = make([]byte, totalLength) + } else { + c.buf = c.buf[:totalLength] + } + + binary.BigEndian.PutUint32(c.buf, uint32(1+len(payload)+padding)) + chacha20.New(c.lengthKey, nonce).XORKeyStream(c.buf, c.buf[:4]) + c.buf[4] = byte(padding) + copy(c.buf[5:], payload) + packetEnd := 5 + len(payload) + padding + if _, err := io.ReadFull(rand, c.buf[5+len(payload):packetEnd]); err != nil { + return err + } + + s.XORKeyStream(c.buf[4:], c.buf[4:packetEnd]) + + var mac [poly1305.TagSize]byte + poly1305.Sum(&mac, c.buf[:packetEnd], &polyKey) + + copy(c.buf[packetEnd:], mac[:]) + + if _, err := w.Write(c.buf); err != nil { + return err + } + return nil +} diff --git a/vendor/golang.org/x/crypto/ssh/client.go b/vendor/golang.org/x/crypto/ssh/client.go new file mode 100644 index 00000000..7b00bff1 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/client.go @@ -0,0 +1,278 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "net" + "os" + "sync" + "time" +) + +// Client implements a traditional SSH client that supports shells, +// subprocesses, TCP port/streamlocal forwarding and tunneled dialing. +type Client struct { + Conn + + handleForwardsOnce sync.Once // guards calling (*Client).handleForwards + + forwards forwardList // forwarded tcpip connections from the remote side + mu sync.Mutex + channelHandlers map[string]chan NewChannel +} + +// HandleChannelOpen returns a channel on which NewChannel requests +// for the given type are sent. If the type already is being handled, +// nil is returned. The channel is closed when the connection is closed. +func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel { + c.mu.Lock() + defer c.mu.Unlock() + if c.channelHandlers == nil { + // The SSH channel has been closed. + c := make(chan NewChannel) + close(c) + return c + } + + ch := c.channelHandlers[channelType] + if ch != nil { + return nil + } + + ch = make(chan NewChannel, chanSize) + c.channelHandlers[channelType] = ch + return ch +} + +// NewClient creates a Client on top of the given connection. +func NewClient(c Conn, chans <-chan NewChannel, reqs <-chan *Request) *Client { + conn := &Client{ + Conn: c, + channelHandlers: make(map[string]chan NewChannel, 1), + } + + go conn.handleGlobalRequests(reqs) + go conn.handleChannelOpens(chans) + go func() { + conn.Wait() + conn.forwards.closeAll() + }() + return conn +} + +// NewClientConn establishes an authenticated SSH connection using c +// as the underlying transport. The Request and NewChannel channels +// must be serviced or the connection will hang. +func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan NewChannel, <-chan *Request, error) { + fullConf := *config + fullConf.SetDefaults() + if fullConf.HostKeyCallback == nil { + c.Close() + return nil, nil, nil, errors.New("ssh: must specify HostKeyCallback") + } + + conn := &connection{ + sshConn: sshConn{conn: c}, + } + + if err := conn.clientHandshake(addr, &fullConf); err != nil { + c.Close() + return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %v", err) + } + conn.mux = newMux(conn.transport) + return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil +} + +// clientHandshake performs the client side key exchange. See RFC 4253 Section +// 7. +func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) error { + if config.ClientVersion != "" { + c.clientVersion = []byte(config.ClientVersion) + } else { + c.clientVersion = []byte(packageVersion) + } + var err error + c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion) + if err != nil { + return err + } + + c.transport = newClientTransport( + newTransport(c.sshConn.conn, config.Rand, true /* is client */), + c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr()) + if err := c.transport.waitSession(); err != nil { + return err + } + + c.sessionID = c.transport.getSessionID() + return c.clientAuthenticate(config) +} + +// verifyHostKeySignature verifies the host key obtained in the key +// exchange. +func verifyHostKeySignature(hostKey PublicKey, result *kexResult) error { + sig, rest, ok := parseSignatureBody(result.Signature) + if len(rest) > 0 || !ok { + return errors.New("ssh: signature parse error") + } + + return hostKey.Verify(result.H, sig) +} + +// NewSession opens a new Session for this client. (A session is a remote +// execution of a program.) +func (c *Client) NewSession() (*Session, error) { + ch, in, err := c.OpenChannel("session", nil) + if err != nil { + return nil, err + } + return newSession(ch, in) +} + +func (c *Client) handleGlobalRequests(incoming <-chan *Request) { + for r := range incoming { + // This handles keepalive messages and matches + // the behaviour of OpenSSH. + r.Reply(false, nil) + } +} + +// handleChannelOpens channel open messages from the remote side. +func (c *Client) handleChannelOpens(in <-chan NewChannel) { + for ch := range in { + c.mu.Lock() + handler := c.channelHandlers[ch.ChannelType()] + c.mu.Unlock() + + if handler != nil { + handler <- ch + } else { + ch.Reject(UnknownChannelType, fmt.Sprintf("unknown channel type: %v", ch.ChannelType())) + } + } + + c.mu.Lock() + for _, ch := range c.channelHandlers { + close(ch) + } + c.channelHandlers = nil + c.mu.Unlock() +} + +// Dial starts a client connection to the given SSH server. It is a +// convenience function that connects to the given network address, +// initiates the SSH handshake, and then sets up a Client. For access +// to incoming channels and requests, use net.Dial with NewClientConn +// instead. +func Dial(network, addr string, config *ClientConfig) (*Client, error) { + conn, err := net.DialTimeout(network, addr, config.Timeout) + if err != nil { + return nil, err + } + c, chans, reqs, err := NewClientConn(conn, addr, config) + if err != nil { + return nil, err + } + return NewClient(c, chans, reqs), nil +} + +// HostKeyCallback is the function type used for verifying server +// keys. A HostKeyCallback must return nil if the host key is OK, or +// an error to reject it. It receives the hostname as passed to Dial +// or NewClientConn. The remote address is the RemoteAddr of the +// net.Conn underlying the SSH connection. +type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error + +// BannerCallback is the function type used for treat the banner sent by +// the server. A BannerCallback receives the message sent by the remote server. +type BannerCallback func(message string) error + +// A ClientConfig structure is used to configure a Client. It must not be +// modified after having been passed to an SSH function. +type ClientConfig struct { + // Config contains configuration that is shared between clients and + // servers. + Config + + // User contains the username to authenticate as. + User string + + // Auth contains possible authentication methods to use with the + // server. Only the first instance of a particular RFC 4252 method will + // be used during authentication. + Auth []AuthMethod + + // HostKeyCallback is called during the cryptographic + // handshake to validate the server's host key. The client + // configuration must supply this callback for the connection + // to succeed. The functions InsecureIgnoreHostKey or + // FixedHostKey can be used for simplistic host key checks. + HostKeyCallback HostKeyCallback + + // BannerCallback is called during the SSH dance to display a custom + // server's message. The client configuration can supply this callback to + // handle it as wished. The function BannerDisplayStderr can be used for + // simplistic display on Stderr. + BannerCallback BannerCallback + + // ClientVersion contains the version identification string that will + // be used for the connection. If empty, a reasonable default is used. + ClientVersion string + + // HostKeyAlgorithms lists the key types that the client will + // accept from the server as host key, in order of + // preference. If empty, a reasonable default is used. Any + // string returned from PublicKey.Type method may be used, or + // any of the CertAlgoXxxx and KeyAlgoXxxx constants. + HostKeyAlgorithms []string + + // Timeout is the maximum amount of time for the TCP connection to establish. + // + // A Timeout of zero means no timeout. + Timeout time.Duration +} + +// InsecureIgnoreHostKey returns a function that can be used for +// ClientConfig.HostKeyCallback to accept any host key. It should +// not be used for production code. +func InsecureIgnoreHostKey() HostKeyCallback { + return func(hostname string, remote net.Addr, key PublicKey) error { + return nil + } +} + +type fixedHostKey struct { + key PublicKey +} + +func (f *fixedHostKey) check(hostname string, remote net.Addr, key PublicKey) error { + if f.key == nil { + return fmt.Errorf("ssh: required host key was nil") + } + if !bytes.Equal(key.Marshal(), f.key.Marshal()) { + return fmt.Errorf("ssh: host key mismatch") + } + return nil +} + +// FixedHostKey returns a function for use in +// ClientConfig.HostKeyCallback to accept only a specific host key. +func FixedHostKey(key PublicKey) HostKeyCallback { + hk := &fixedHostKey{key} + return hk.check +} + +// BannerDisplayStderr returns a function that can be used for +// ClientConfig.BannerCallback to display banners on os.Stderr. +func BannerDisplayStderr() BannerCallback { + return func(banner string) error { + _, err := os.Stderr.WriteString(banner) + + return err + } +} diff --git a/vendor/golang.org/x/crypto/ssh/client_auth.go b/vendor/golang.org/x/crypto/ssh/client_auth.go new file mode 100644 index 00000000..5f44b774 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/client_auth.go @@ -0,0 +1,525 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" +) + +type authResult int + +const ( + authFailure authResult = iota + authPartialSuccess + authSuccess +) + +// clientAuthenticate authenticates with the remote server. See RFC 4252. +func (c *connection) clientAuthenticate(config *ClientConfig) error { + // initiate user auth session + if err := c.transport.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})); err != nil { + return err + } + packet, err := c.transport.readPacket() + if err != nil { + return err + } + var serviceAccept serviceAcceptMsg + if err := Unmarshal(packet, &serviceAccept); err != nil { + return err + } + + // during the authentication phase the client first attempts the "none" method + // then any untried methods suggested by the server. + tried := make(map[string]bool) + var lastMethods []string + + sessionID := c.transport.getSessionID() + for auth := AuthMethod(new(noneAuth)); auth != nil; { + ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand) + if err != nil { + return err + } + if ok == authSuccess { + // success + return nil + } else if ok == authFailure { + tried[auth.method()] = true + } + if methods == nil { + methods = lastMethods + } + lastMethods = methods + + auth = nil + + findNext: + for _, a := range config.Auth { + candidateMethod := a.method() + if tried[candidateMethod] { + continue + } + for _, meth := range methods { + if meth == candidateMethod { + auth = a + break findNext + } + } + } + } + return fmt.Errorf("ssh: unable to authenticate, attempted methods %v, no supported methods remain", keys(tried)) +} + +func keys(m map[string]bool) []string { + s := make([]string, 0, len(m)) + + for key := range m { + s = append(s, key) + } + return s +} + +// An AuthMethod represents an instance of an RFC 4252 authentication method. +type AuthMethod interface { + // auth authenticates user over transport t. + // Returns true if authentication is successful. + // If authentication is not successful, a []string of alternative + // method names is returned. If the slice is nil, it will be ignored + // and the previous set of possible methods will be reused. + auth(session []byte, user string, p packetConn, rand io.Reader) (authResult, []string, error) + + // method returns the RFC 4252 method name. + method() string +} + +// "none" authentication, RFC 4252 section 5.2. +type noneAuth int + +func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { + if err := c.writePacket(Marshal(&userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: "none", + })); err != nil { + return authFailure, nil, err + } + + return handleAuthResponse(c) +} + +func (n *noneAuth) method() string { + return "none" +} + +// passwordCallback is an AuthMethod that fetches the password through +// a function call, e.g. by prompting the user. +type passwordCallback func() (password string, err error) + +func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { + type passwordAuthMsg struct { + User string `sshtype:"50"` + Service string + Method string + Reply bool + Password string + } + + pw, err := cb() + // REVIEW NOTE: is there a need to support skipping a password attempt? + // The program may only find out that the user doesn't have a password + // when prompting. + if err != nil { + return authFailure, nil, err + } + + if err := c.writePacket(Marshal(&passwordAuthMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + Reply: false, + Password: pw, + })); err != nil { + return authFailure, nil, err + } + + return handleAuthResponse(c) +} + +func (cb passwordCallback) method() string { + return "password" +} + +// Password returns an AuthMethod using the given password. +func Password(secret string) AuthMethod { + return passwordCallback(func() (string, error) { return secret, nil }) +} + +// PasswordCallback returns an AuthMethod that uses a callback for +// fetching a password. +func PasswordCallback(prompt func() (secret string, err error)) AuthMethod { + return passwordCallback(prompt) +} + +type publickeyAuthMsg struct { + User string `sshtype:"50"` + Service string + Method string + // HasSig indicates to the receiver packet that the auth request is signed and + // should be used for authentication of the request. + HasSig bool + Algoname string + PubKey []byte + // Sig is tagged with "rest" so Marshal will exclude it during + // validateKey + Sig []byte `ssh:"rest"` +} + +// publicKeyCallback is an AuthMethod that uses a set of key +// pairs for authentication. +type publicKeyCallback func() ([]Signer, error) + +func (cb publicKeyCallback) method() string { + return "publickey" +} + +func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { + // Authentication is performed by sending an enquiry to test if a key is + // acceptable to the remote. If the key is acceptable, the client will + // attempt to authenticate with the valid key. If not the client will repeat + // the process with the remaining keys. + + signers, err := cb() + if err != nil { + return authFailure, nil, err + } + var methods []string + for _, signer := range signers { + ok, err := validateKey(signer.PublicKey(), user, c) + if err != nil { + return authFailure, nil, err + } + if !ok { + continue + } + + pub := signer.PublicKey() + pubKey := pub.Marshal() + sign, err := signer.Sign(rand, buildDataSignedForAuth(session, userAuthRequestMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + }, []byte(pub.Type()), pubKey)) + if err != nil { + return authFailure, nil, err + } + + // manually wrap the serialized signature in a string + s := Marshal(sign) + sig := make([]byte, stringLength(len(s))) + marshalString(sig, s) + msg := publickeyAuthMsg{ + User: user, + Service: serviceSSH, + Method: cb.method(), + HasSig: true, + Algoname: pub.Type(), + PubKey: pubKey, + Sig: sig, + } + p := Marshal(&msg) + if err := c.writePacket(p); err != nil { + return authFailure, nil, err + } + var success authResult + success, methods, err = handleAuthResponse(c) + if err != nil { + return authFailure, nil, err + } + + // If authentication succeeds or the list of available methods does not + // contain the "publickey" method, do not attempt to authenticate with any + // other keys. According to RFC 4252 Section 7, the latter can occur when + // additional authentication methods are required. + if success == authSuccess || !containsMethod(methods, cb.method()) { + return success, methods, err + } + } + + return authFailure, methods, nil +} + +func containsMethod(methods []string, method string) bool { + for _, m := range methods { + if m == method { + return true + } + } + + return false +} + +// validateKey validates the key provided is acceptable to the server. +func validateKey(key PublicKey, user string, c packetConn) (bool, error) { + pubKey := key.Marshal() + msg := publickeyAuthMsg{ + User: user, + Service: serviceSSH, + Method: "publickey", + HasSig: false, + Algoname: key.Type(), + PubKey: pubKey, + } + if err := c.writePacket(Marshal(&msg)); err != nil { + return false, err + } + + return confirmKeyAck(key, c) +} + +func confirmKeyAck(key PublicKey, c packetConn) (bool, error) { + pubKey := key.Marshal() + algoname := key.Type() + + for { + packet, err := c.readPacket() + if err != nil { + return false, err + } + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return false, err + } + case msgUserAuthPubKeyOk: + var msg userAuthPubKeyOkMsg + if err := Unmarshal(packet, &msg); err != nil { + return false, err + } + if msg.Algo != algoname || !bytes.Equal(msg.PubKey, pubKey) { + return false, nil + } + return true, nil + case msgUserAuthFailure: + return false, nil + default: + return false, unexpectedMessageError(msgUserAuthSuccess, packet[0]) + } + } +} + +// PublicKeys returns an AuthMethod that uses the given key +// pairs. +func PublicKeys(signers ...Signer) AuthMethod { + return publicKeyCallback(func() ([]Signer, error) { return signers, nil }) +} + +// PublicKeysCallback returns an AuthMethod that runs the given +// function to obtain a list of key pairs. +func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMethod { + return publicKeyCallback(getSigners) +} + +// handleAuthResponse returns whether the preceding authentication request succeeded +// along with a list of remaining authentication methods to try next and +// an error if an unexpected response was received. +func handleAuthResponse(c packetConn) (authResult, []string, error) { + for { + packet, err := c.readPacket() + if err != nil { + return authFailure, nil, err + } + + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } + case msgUserAuthFailure: + var msg userAuthFailureMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil + } + return authFailure, msg.Methods, nil + case msgUserAuthSuccess: + return authSuccess, nil, nil + default: + return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0]) + } + } +} + +func handleBannerResponse(c packetConn, packet []byte) error { + var msg userAuthBannerMsg + if err := Unmarshal(packet, &msg); err != nil { + return err + } + + transport, ok := c.(*handshakeTransport) + if !ok { + return nil + } + + if transport.bannerCallback != nil { + return transport.bannerCallback(msg.Message) + } + + return nil +} + +// KeyboardInteractiveChallenge should print questions, optionally +// disabling echoing (e.g. for passwords), and return all the answers. +// Challenge may be called multiple times in a single session. After +// successful authentication, the server may send a challenge with no +// questions, for which the user and instruction messages should be +// printed. RFC 4256 section 3.3 details how the UI should behave for +// both CLI and GUI environments. +type KeyboardInteractiveChallenge func(user, instruction string, questions []string, echos []bool) (answers []string, err error) + +// KeyboardInteractive returns an AuthMethod using a prompt/response +// sequence controlled by the server. +func KeyboardInteractive(challenge KeyboardInteractiveChallenge) AuthMethod { + return challenge +} + +func (cb KeyboardInteractiveChallenge) method() string { + return "keyboard-interactive" +} + +func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) { + type initiateMsg struct { + User string `sshtype:"50"` + Service string + Method string + Language string + Submethods string + } + + if err := c.writePacket(Marshal(&initiateMsg{ + User: user, + Service: serviceSSH, + Method: "keyboard-interactive", + })); err != nil { + return authFailure, nil, err + } + + for { + packet, err := c.readPacket() + if err != nil { + return authFailure, nil, err + } + + // like handleAuthResponse, but with less options. + switch packet[0] { + case msgUserAuthBanner: + if err := handleBannerResponse(c, packet); err != nil { + return authFailure, nil, err + } + continue + case msgUserAuthInfoRequest: + // OK + case msgUserAuthFailure: + var msg userAuthFailureMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + if msg.PartialSuccess { + return authPartialSuccess, msg.Methods, nil + } + return authFailure, msg.Methods, nil + case msgUserAuthSuccess: + return authSuccess, nil, nil + default: + return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0]) + } + + var msg userAuthInfoRequestMsg + if err := Unmarshal(packet, &msg); err != nil { + return authFailure, nil, err + } + + // Manually unpack the prompt/echo pairs. + rest := msg.Prompts + var prompts []string + var echos []bool + for i := 0; i < int(msg.NumPrompts); i++ { + prompt, r, ok := parseString(rest) + if !ok || len(r) == 0 { + return authFailure, nil, errors.New("ssh: prompt format error") + } + prompts = append(prompts, string(prompt)) + echos = append(echos, r[0] != 0) + rest = r[1:] + } + + if len(rest) != 0 { + return authFailure, nil, errors.New("ssh: extra data following keyboard-interactive pairs") + } + + answers, err := cb(msg.User, msg.Instruction, prompts, echos) + if err != nil { + return authFailure, nil, err + } + + if len(answers) != len(prompts) { + return authFailure, nil, errors.New("ssh: not enough answers from keyboard-interactive callback") + } + responseLength := 1 + 4 + for _, a := range answers { + responseLength += stringLength(len(a)) + } + serialized := make([]byte, responseLength) + p := serialized + p[0] = msgUserAuthInfoResponse + p = p[1:] + p = marshalUint32(p, uint32(len(answers))) + for _, a := range answers { + p = marshalString(p, []byte(a)) + } + + if err := c.writePacket(serialized); err != nil { + return authFailure, nil, err + } + } +} + +type retryableAuthMethod struct { + authMethod AuthMethod + maxTries int +} + +func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader) (ok authResult, methods []string, err error) { + for i := 0; r.maxTries <= 0 || i < r.maxTries; i++ { + ok, methods, err = r.authMethod.auth(session, user, c, rand) + if ok != authFailure || err != nil { // either success, partial success or error terminate + return ok, methods, err + } + } + return ok, methods, err +} + +func (r *retryableAuthMethod) method() string { + return r.authMethod.method() +} + +// RetryableAuthMethod is a decorator for other auth methods enabling them to +// be retried up to maxTries before considering that AuthMethod itself failed. +// If maxTries is <= 0, will retry indefinitely +// +// This is useful for interactive clients using challenge/response type +// authentication (e.g. Keyboard-Interactive, Password, etc) where the user +// could mistype their response resulting in the server issuing a +// SSH_MSG_USERAUTH_FAILURE (rfc4252 #8 [password] and rfc4256 #3.4 +// [keyboard-interactive]); Without this decorator, the non-retryable +// AuthMethod would be removed from future consideration, and never tried again +// (and so the user would never be able to retry their entry). +func RetryableAuthMethod(auth AuthMethod, maxTries int) AuthMethod { + return &retryableAuthMethod{authMethod: auth, maxTries: maxTries} +} diff --git a/vendor/golang.org/x/crypto/ssh/common.go b/vendor/golang.org/x/crypto/ssh/common.go new file mode 100644 index 00000000..04f3620b --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/common.go @@ -0,0 +1,383 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto" + "crypto/rand" + "fmt" + "io" + "math" + "sync" + + _ "crypto/sha1" + _ "crypto/sha256" + _ "crypto/sha512" +) + +// These are string constants in the SSH protocol. +const ( + compressionNone = "none" + serviceUserAuth = "ssh-userauth" + serviceSSH = "ssh-connection" +) + +// supportedCiphers lists ciphers we support but might not recommend. +var supportedCiphers = []string{ + "aes128-ctr", "aes192-ctr", "aes256-ctr", + "aes128-gcm@openssh.com", + chacha20Poly1305ID, + "arcfour256", "arcfour128", "arcfour", + aes128cbcID, + tripledescbcID, +} + +// preferredCiphers specifies the default preference for ciphers. +var preferredCiphers = []string{ + "aes128-gcm@openssh.com", + chacha20Poly1305ID, + "aes128-ctr", "aes192-ctr", "aes256-ctr", +} + +// supportedKexAlgos specifies the supported key-exchange algorithms in +// preference order. +var supportedKexAlgos = []string{ + kexAlgoCurve25519SHA256, + // P384 and P521 are not constant-time yet, but since we don't + // reuse ephemeral keys, using them for ECDH should be OK. + kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521, + kexAlgoDH14SHA1, kexAlgoDH1SHA1, +} + +// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods +// of authenticating servers) in preference order. +var supportedHostKeyAlgos = []string{ + CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, + CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01, + + KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, + KeyAlgoRSA, KeyAlgoDSA, + + KeyAlgoED25519, +} + +// supportedMACs specifies a default set of MAC algorithms in preference order. +// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed +// because they have reached the end of their useful life. +var supportedMACs = []string{ + "hmac-sha2-256-etm@openssh.com", "hmac-sha2-256", "hmac-sha1", "hmac-sha1-96", +} + +var supportedCompressions = []string{compressionNone} + +// hashFuncs keeps the mapping of supported algorithms to their respective +// hashes needed for signature verification. +var hashFuncs = map[string]crypto.Hash{ + KeyAlgoRSA: crypto.SHA1, + KeyAlgoDSA: crypto.SHA1, + KeyAlgoECDSA256: crypto.SHA256, + KeyAlgoECDSA384: crypto.SHA384, + KeyAlgoECDSA521: crypto.SHA512, + CertAlgoRSAv01: crypto.SHA1, + CertAlgoDSAv01: crypto.SHA1, + CertAlgoECDSA256v01: crypto.SHA256, + CertAlgoECDSA384v01: crypto.SHA384, + CertAlgoECDSA521v01: crypto.SHA512, +} + +// unexpectedMessageError results when the SSH message that we received didn't +// match what we wanted. +func unexpectedMessageError(expected, got uint8) error { + return fmt.Errorf("ssh: unexpected message type %d (expected %d)", got, expected) +} + +// parseError results from a malformed SSH message. +func parseError(tag uint8) error { + return fmt.Errorf("ssh: parse error in message type %d", tag) +} + +func findCommon(what string, client []string, server []string) (common string, err error) { + for _, c := range client { + for _, s := range server { + if c == s { + return c, nil + } + } + } + return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server) +} + +type directionAlgorithms struct { + Cipher string + MAC string + Compression string +} + +// rekeyBytes returns a rekeying intervals in bytes. +func (a *directionAlgorithms) rekeyBytes() int64 { + // According to RFC4344 block ciphers should rekey after + // 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is + // 128. + switch a.Cipher { + case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcmCipherID, aes128cbcID: + return 16 * (1 << 32) + + } + + // For others, stick with RFC4253 recommendation to rekey after 1 Gb of data. + return 1 << 30 +} + +type algorithms struct { + kex string + hostKey string + w directionAlgorithms + r directionAlgorithms +} + +func findAgreedAlgorithms(clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) { + result := &algorithms{} + + result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos) + if err != nil { + return + } + + result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos) + if err != nil { + return + } + + result.w.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer) + if err != nil { + return + } + + result.r.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient) + if err != nil { + return + } + + result.w.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer) + if err != nil { + return + } + + result.r.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient) + if err != nil { + return + } + + result.w.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer) + if err != nil { + return + } + + result.r.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient) + if err != nil { + return + } + + return result, nil +} + +// If rekeythreshold is too small, we can't make any progress sending +// stuff. +const minRekeyThreshold uint64 = 256 + +// Config contains configuration data common to both ServerConfig and +// ClientConfig. +type Config struct { + // Rand provides the source of entropy for cryptographic + // primitives. If Rand is nil, the cryptographic random reader + // in package crypto/rand will be used. + Rand io.Reader + + // The maximum number of bytes sent or received after which a + // new key is negotiated. It must be at least 256. If + // unspecified, a size suitable for the chosen cipher is used. + RekeyThreshold uint64 + + // The allowed key exchanges algorithms. If unspecified then a + // default set of algorithms is used. + KeyExchanges []string + + // The allowed cipher algorithms. If unspecified then a sensible + // default is used. + Ciphers []string + + // The allowed MAC algorithms. If unspecified then a sensible default + // is used. + MACs []string +} + +// SetDefaults sets sensible values for unset fields in config. This is +// exported for testing: Configs passed to SSH functions are copied and have +// default values set automatically. +func (c *Config) SetDefaults() { + if c.Rand == nil { + c.Rand = rand.Reader + } + if c.Ciphers == nil { + c.Ciphers = preferredCiphers + } + var ciphers []string + for _, c := range c.Ciphers { + if cipherModes[c] != nil { + // reject the cipher if we have no cipherModes definition + ciphers = append(ciphers, c) + } + } + c.Ciphers = ciphers + + if c.KeyExchanges == nil { + c.KeyExchanges = supportedKexAlgos + } + + if c.MACs == nil { + c.MACs = supportedMACs + } + + if c.RekeyThreshold == 0 { + // cipher specific default + } else if c.RekeyThreshold < minRekeyThreshold { + c.RekeyThreshold = minRekeyThreshold + } else if c.RekeyThreshold >= math.MaxInt64 { + // Avoid weirdness if somebody uses -1 as a threshold. + c.RekeyThreshold = math.MaxInt64 + } +} + +// buildDataSignedForAuth returns the data that is signed in order to prove +// possession of a private key. See RFC 4252, section 7. +func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo, pubKey []byte) []byte { + data := struct { + Session []byte + Type byte + User string + Service string + Method string + Sign bool + Algo []byte + PubKey []byte + }{ + sessionID, + msgUserAuthRequest, + req.User, + req.Service, + req.Method, + true, + algo, + pubKey, + } + return Marshal(data) +} + +func appendU16(buf []byte, n uint16) []byte { + return append(buf, byte(n>>8), byte(n)) +} + +func appendU32(buf []byte, n uint32) []byte { + return append(buf, byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) +} + +func appendU64(buf []byte, n uint64) []byte { + return append(buf, + byte(n>>56), byte(n>>48), byte(n>>40), byte(n>>32), + byte(n>>24), byte(n>>16), byte(n>>8), byte(n)) +} + +func appendInt(buf []byte, n int) []byte { + return appendU32(buf, uint32(n)) +} + +func appendString(buf []byte, s string) []byte { + buf = appendU32(buf, uint32(len(s))) + buf = append(buf, s...) + return buf +} + +func appendBool(buf []byte, b bool) []byte { + if b { + return append(buf, 1) + } + return append(buf, 0) +} + +// newCond is a helper to hide the fact that there is no usable zero +// value for sync.Cond. +func newCond() *sync.Cond { return sync.NewCond(new(sync.Mutex)) } + +// window represents the buffer available to clients +// wishing to write to a channel. +type window struct { + *sync.Cond + win uint32 // RFC 4254 5.2 says the window size can grow to 2^32-1 + writeWaiters int + closed bool +} + +// add adds win to the amount of window available +// for consumers. +func (w *window) add(win uint32) bool { + // a zero sized window adjust is a noop. + if win == 0 { + return true + } + w.L.Lock() + if w.win+win < win { + w.L.Unlock() + return false + } + w.win += win + // It is unusual that multiple goroutines would be attempting to reserve + // window space, but not guaranteed. Use broadcast to notify all waiters + // that additional window is available. + w.Broadcast() + w.L.Unlock() + return true +} + +// close sets the window to closed, so all reservations fail +// immediately. +func (w *window) close() { + w.L.Lock() + w.closed = true + w.Broadcast() + w.L.Unlock() +} + +// reserve reserves win from the available window capacity. +// If no capacity remains, reserve will block. reserve may +// return less than requested. +func (w *window) reserve(win uint32) (uint32, error) { + var err error + w.L.Lock() + w.writeWaiters++ + w.Broadcast() + for w.win == 0 && !w.closed { + w.Wait() + } + w.writeWaiters-- + if w.win < win { + win = w.win + } + w.win -= win + if w.closed { + err = io.EOF + } + w.L.Unlock() + return win, err +} + +// waitWriterBlocked waits until some goroutine is blocked for further +// writes. It is used in tests only. +func (w *window) waitWriterBlocked() { + w.Cond.L.Lock() + for w.writeWaiters == 0 { + w.Cond.Wait() + } + w.Cond.L.Unlock() +} diff --git a/vendor/golang.org/x/crypto/ssh/connection.go b/vendor/golang.org/x/crypto/ssh/connection.go new file mode 100644 index 00000000..fd6b0681 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/connection.go @@ -0,0 +1,143 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "fmt" + "net" +) + +// OpenChannelError is returned if the other side rejects an +// OpenChannel request. +type OpenChannelError struct { + Reason RejectionReason + Message string +} + +func (e *OpenChannelError) Error() string { + return fmt.Sprintf("ssh: rejected: %s (%s)", e.Reason, e.Message) +} + +// ConnMetadata holds metadata for the connection. +type ConnMetadata interface { + // User returns the user ID for this connection. + User() string + + // SessionID returns the session hash, also denoted by H. + SessionID() []byte + + // ClientVersion returns the client's version string as hashed + // into the session ID. + ClientVersion() []byte + + // ServerVersion returns the server's version string as hashed + // into the session ID. + ServerVersion() []byte + + // RemoteAddr returns the remote address for this connection. + RemoteAddr() net.Addr + + // LocalAddr returns the local address for this connection. + LocalAddr() net.Addr +} + +// Conn represents an SSH connection for both server and client roles. +// Conn is the basis for implementing an application layer, such +// as ClientConn, which implements the traditional shell access for +// clients. +type Conn interface { + ConnMetadata + + // SendRequest sends a global request, and returns the + // reply. If wantReply is true, it returns the response status + // and payload. See also RFC4254, section 4. + SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) + + // OpenChannel tries to open an channel. If the request is + // rejected, it returns *OpenChannelError. On success it returns + // the SSH Channel and a Go channel for incoming, out-of-band + // requests. The Go channel must be serviced, or the + // connection will hang. + OpenChannel(name string, data []byte) (Channel, <-chan *Request, error) + + // Close closes the underlying network connection + Close() error + + // Wait blocks until the connection has shut down, and returns the + // error causing the shutdown. + Wait() error + + // TODO(hanwen): consider exposing: + // RequestKeyChange + // Disconnect +} + +// DiscardRequests consumes and rejects all requests from the +// passed-in channel. +func DiscardRequests(in <-chan *Request) { + for req := range in { + if req.WantReply { + req.Reply(false, nil) + } + } +} + +// A connection represents an incoming connection. +type connection struct { + transport *handshakeTransport + sshConn + + // The connection protocol. + *mux +} + +func (c *connection) Close() error { + return c.sshConn.conn.Close() +} + +// sshconn provides net.Conn metadata, but disallows direct reads and +// writes. +type sshConn struct { + conn net.Conn + + user string + sessionID []byte + clientVersion []byte + serverVersion []byte +} + +func dup(src []byte) []byte { + dst := make([]byte, len(src)) + copy(dst, src) + return dst +} + +func (c *sshConn) User() string { + return c.user +} + +func (c *sshConn) RemoteAddr() net.Addr { + return c.conn.RemoteAddr() +} + +func (c *sshConn) Close() error { + return c.conn.Close() +} + +func (c *sshConn) LocalAddr() net.Addr { + return c.conn.LocalAddr() +} + +func (c *sshConn) SessionID() []byte { + return dup(c.sessionID) +} + +func (c *sshConn) ClientVersion() []byte { + return dup(c.clientVersion) +} + +func (c *sshConn) ServerVersion() []byte { + return dup(c.serverVersion) +} diff --git a/vendor/golang.org/x/crypto/ssh/doc.go b/vendor/golang.org/x/crypto/ssh/doc.go new file mode 100644 index 00000000..67b7322c --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/doc.go @@ -0,0 +1,21 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +/* +Package ssh implements an SSH client and server. + +SSH is a transport security protocol, an authentication protocol and a +family of application protocols. The most typical application level +protocol is a remote shell and this is specifically implemented. However, +the multiplexed nature of SSH is exposed to users that wish to support +others. + +References: + [PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD + [SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1 + +This package does not fall under the stability promise of the Go language itself, +so its API may be changed when pressing needs arise. +*/ +package ssh // import "golang.org/x/crypto/ssh" diff --git a/vendor/golang.org/x/crypto/ssh/handshake.go b/vendor/golang.org/x/crypto/ssh/handshake.go new file mode 100644 index 00000000..4f7912ec --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/handshake.go @@ -0,0 +1,646 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto/rand" + "errors" + "fmt" + "io" + "log" + "net" + "sync" +) + +// debugHandshake, if set, prints messages sent and received. Key +// exchange messages are printed as if DH were used, so the debug +// messages are wrong when using ECDH. +const debugHandshake = false + +// chanSize sets the amount of buffering SSH connections. This is +// primarily for testing: setting chanSize=0 uncovers deadlocks more +// quickly. +const chanSize = 16 + +// keyingTransport is a packet based transport that supports key +// changes. It need not be thread-safe. It should pass through +// msgNewKeys in both directions. +type keyingTransport interface { + packetConn + + // prepareKeyChange sets up a key change. The key change for a + // direction will be effected if a msgNewKeys message is sent + // or received. + prepareKeyChange(*algorithms, *kexResult) error +} + +// handshakeTransport implements rekeying on top of a keyingTransport +// and offers a thread-safe writePacket() interface. +type handshakeTransport struct { + conn keyingTransport + config *Config + + serverVersion []byte + clientVersion []byte + + // hostKeys is non-empty if we are the server. In that case, + // it contains all host keys that can be used to sign the + // connection. + hostKeys []Signer + + // hostKeyAlgorithms is non-empty if we are the client. In that case, + // we accept these key types from the server as host key. + hostKeyAlgorithms []string + + // On read error, incoming is closed, and readError is set. + incoming chan []byte + readError error + + mu sync.Mutex + writeError error + sentInitPacket []byte + sentInitMsg *kexInitMsg + pendingPackets [][]byte // Used when a key exchange is in progress. + + // If the read loop wants to schedule a kex, it pings this + // channel, and the write loop will send out a kex + // message. + requestKex chan struct{} + + // If the other side requests or confirms a kex, its kexInit + // packet is sent here for the write loop to find it. + startKex chan *pendingKex + + // data for host key checking + hostKeyCallback HostKeyCallback + dialAddress string + remoteAddr net.Addr + + // bannerCallback is non-empty if we are the client and it has been set in + // ClientConfig. In that case it is called during the user authentication + // dance to handle a custom server's message. + bannerCallback BannerCallback + + // Algorithms agreed in the last key exchange. + algorithms *algorithms + + readPacketsLeft uint32 + readBytesLeft int64 + + writePacketsLeft uint32 + writeBytesLeft int64 + + // The session ID or nil if first kex did not complete yet. + sessionID []byte +} + +type pendingKex struct { + otherInit []byte + done chan error +} + +func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion, serverVersion []byte) *handshakeTransport { + t := &handshakeTransport{ + conn: conn, + serverVersion: serverVersion, + clientVersion: clientVersion, + incoming: make(chan []byte, chanSize), + requestKex: make(chan struct{}, 1), + startKex: make(chan *pendingKex, 1), + + config: config, + } + t.resetReadThresholds() + t.resetWriteThresholds() + + // We always start with a mandatory key exchange. + t.requestKex <- struct{}{} + return t +} + +func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ClientConfig, dialAddr string, addr net.Addr) *handshakeTransport { + t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion) + t.dialAddress = dialAddr + t.remoteAddr = addr + t.hostKeyCallback = config.HostKeyCallback + t.bannerCallback = config.BannerCallback + if config.HostKeyAlgorithms != nil { + t.hostKeyAlgorithms = config.HostKeyAlgorithms + } else { + t.hostKeyAlgorithms = supportedHostKeyAlgos + } + go t.readLoop() + go t.kexLoop() + return t +} + +func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ServerConfig) *handshakeTransport { + t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion) + t.hostKeys = config.hostKeys + go t.readLoop() + go t.kexLoop() + return t +} + +func (t *handshakeTransport) getSessionID() []byte { + return t.sessionID +} + +// waitSession waits for the session to be established. This should be +// the first thing to call after instantiating handshakeTransport. +func (t *handshakeTransport) waitSession() error { + p, err := t.readPacket() + if err != nil { + return err + } + if p[0] != msgNewKeys { + return fmt.Errorf("ssh: first packet should be msgNewKeys") + } + + return nil +} + +func (t *handshakeTransport) id() string { + if len(t.hostKeys) > 0 { + return "server" + } + return "client" +} + +func (t *handshakeTransport) printPacket(p []byte, write bool) { + action := "got" + if write { + action = "sent" + } + + if p[0] == msgChannelData || p[0] == msgChannelExtendedData { + log.Printf("%s %s data (packet %d bytes)", t.id(), action, len(p)) + } else { + msg, err := decode(p) + log.Printf("%s %s %T %v (%v)", t.id(), action, msg, msg, err) + } +} + +func (t *handshakeTransport) readPacket() ([]byte, error) { + p, ok := <-t.incoming + if !ok { + return nil, t.readError + } + return p, nil +} + +func (t *handshakeTransport) readLoop() { + first := true + for { + p, err := t.readOnePacket(first) + first = false + if err != nil { + t.readError = err + close(t.incoming) + break + } + if p[0] == msgIgnore || p[0] == msgDebug { + continue + } + t.incoming <- p + } + + // Stop writers too. + t.recordWriteError(t.readError) + + // Unblock the writer should it wait for this. + close(t.startKex) + + // Don't close t.requestKex; it's also written to from writePacket. +} + +func (t *handshakeTransport) pushPacket(p []byte) error { + if debugHandshake { + t.printPacket(p, true) + } + return t.conn.writePacket(p) +} + +func (t *handshakeTransport) getWriteError() error { + t.mu.Lock() + defer t.mu.Unlock() + return t.writeError +} + +func (t *handshakeTransport) recordWriteError(err error) { + t.mu.Lock() + defer t.mu.Unlock() + if t.writeError == nil && err != nil { + t.writeError = err + } +} + +func (t *handshakeTransport) requestKeyExchange() { + select { + case t.requestKex <- struct{}{}: + default: + // something already requested a kex, so do nothing. + } +} + +func (t *handshakeTransport) resetWriteThresholds() { + t.writePacketsLeft = packetRekeyThreshold + if t.config.RekeyThreshold > 0 { + t.writeBytesLeft = int64(t.config.RekeyThreshold) + } else if t.algorithms != nil { + t.writeBytesLeft = t.algorithms.w.rekeyBytes() + } else { + t.writeBytesLeft = 1 << 30 + } +} + +func (t *handshakeTransport) kexLoop() { + +write: + for t.getWriteError() == nil { + var request *pendingKex + var sent bool + + for request == nil || !sent { + var ok bool + select { + case request, ok = <-t.startKex: + if !ok { + break write + } + case <-t.requestKex: + break + } + + if !sent { + if err := t.sendKexInit(); err != nil { + t.recordWriteError(err) + break + } + sent = true + } + } + + if err := t.getWriteError(); err != nil { + if request != nil { + request.done <- err + } + break + } + + // We're not servicing t.requestKex, but that is OK: + // we never block on sending to t.requestKex. + + // We're not servicing t.startKex, but the remote end + // has just sent us a kexInitMsg, so it can't send + // another key change request, until we close the done + // channel on the pendingKex request. + + err := t.enterKeyExchange(request.otherInit) + + t.mu.Lock() + t.writeError = err + t.sentInitPacket = nil + t.sentInitMsg = nil + + t.resetWriteThresholds() + + // we have completed the key exchange. Since the + // reader is still blocked, it is safe to clear out + // the requestKex channel. This avoids the situation + // where: 1) we consumed our own request for the + // initial kex, and 2) the kex from the remote side + // caused another send on the requestKex channel, + clear: + for { + select { + case <-t.requestKex: + // + default: + break clear + } + } + + request.done <- t.writeError + + // kex finished. Push packets that we received while + // the kex was in progress. Don't look at t.startKex + // and don't increment writtenSinceKex: if we trigger + // another kex while we are still busy with the last + // one, things will become very confusing. + for _, p := range t.pendingPackets { + t.writeError = t.pushPacket(p) + if t.writeError != nil { + break + } + } + t.pendingPackets = t.pendingPackets[:0] + t.mu.Unlock() + } + + // drain startKex channel. We don't service t.requestKex + // because nobody does blocking sends there. + go func() { + for init := range t.startKex { + init.done <- t.writeError + } + }() + + // Unblock reader. + t.conn.Close() +} + +// The protocol uses uint32 for packet counters, so we can't let them +// reach 1<<32. We will actually read and write more packets than +// this, though: the other side may send more packets, and after we +// hit this limit on writing we will send a few more packets for the +// key exchange itself. +const packetRekeyThreshold = (1 << 31) + +func (t *handshakeTransport) resetReadThresholds() { + t.readPacketsLeft = packetRekeyThreshold + if t.config.RekeyThreshold > 0 { + t.readBytesLeft = int64(t.config.RekeyThreshold) + } else if t.algorithms != nil { + t.readBytesLeft = t.algorithms.r.rekeyBytes() + } else { + t.readBytesLeft = 1 << 30 + } +} + +func (t *handshakeTransport) readOnePacket(first bool) ([]byte, error) { + p, err := t.conn.readPacket() + if err != nil { + return nil, err + } + + if t.readPacketsLeft > 0 { + t.readPacketsLeft-- + } else { + t.requestKeyExchange() + } + + if t.readBytesLeft > 0 { + t.readBytesLeft -= int64(len(p)) + } else { + t.requestKeyExchange() + } + + if debugHandshake { + t.printPacket(p, false) + } + + if first && p[0] != msgKexInit { + return nil, fmt.Errorf("ssh: first packet should be msgKexInit") + } + + if p[0] != msgKexInit { + return p, nil + } + + firstKex := t.sessionID == nil + + kex := pendingKex{ + done: make(chan error, 1), + otherInit: p, + } + t.startKex <- &kex + err = <-kex.done + + if debugHandshake { + log.Printf("%s exited key exchange (first %v), err %v", t.id(), firstKex, err) + } + + if err != nil { + return nil, err + } + + t.resetReadThresholds() + + // By default, a key exchange is hidden from higher layers by + // translating it into msgIgnore. + successPacket := []byte{msgIgnore} + if firstKex { + // sendKexInit() for the first kex waits for + // msgNewKeys so the authentication process is + // guaranteed to happen over an encrypted transport. + successPacket = []byte{msgNewKeys} + } + + return successPacket, nil +} + +// sendKexInit sends a key change message. +func (t *handshakeTransport) sendKexInit() error { + t.mu.Lock() + defer t.mu.Unlock() + if t.sentInitMsg != nil { + // kexInits may be sent either in response to the other side, + // or because our side wants to initiate a key change, so we + // may have already sent a kexInit. In that case, don't send a + // second kexInit. + return nil + } + + msg := &kexInitMsg{ + KexAlgos: t.config.KeyExchanges, + CiphersClientServer: t.config.Ciphers, + CiphersServerClient: t.config.Ciphers, + MACsClientServer: t.config.MACs, + MACsServerClient: t.config.MACs, + CompressionClientServer: supportedCompressions, + CompressionServerClient: supportedCompressions, + } + io.ReadFull(rand.Reader, msg.Cookie[:]) + + if len(t.hostKeys) > 0 { + for _, k := range t.hostKeys { + msg.ServerHostKeyAlgos = append( + msg.ServerHostKeyAlgos, k.PublicKey().Type()) + } + } else { + msg.ServerHostKeyAlgos = t.hostKeyAlgorithms + } + packet := Marshal(msg) + + // writePacket destroys the contents, so save a copy. + packetCopy := make([]byte, len(packet)) + copy(packetCopy, packet) + + if err := t.pushPacket(packetCopy); err != nil { + return err + } + + t.sentInitMsg = msg + t.sentInitPacket = packet + + return nil +} + +func (t *handshakeTransport) writePacket(p []byte) error { + switch p[0] { + case msgKexInit: + return errors.New("ssh: only handshakeTransport can send kexInit") + case msgNewKeys: + return errors.New("ssh: only handshakeTransport can send newKeys") + } + + t.mu.Lock() + defer t.mu.Unlock() + if t.writeError != nil { + return t.writeError + } + + if t.sentInitMsg != nil { + // Copy the packet so the writer can reuse the buffer. + cp := make([]byte, len(p)) + copy(cp, p) + t.pendingPackets = append(t.pendingPackets, cp) + return nil + } + + if t.writeBytesLeft > 0 { + t.writeBytesLeft -= int64(len(p)) + } else { + t.requestKeyExchange() + } + + if t.writePacketsLeft > 0 { + t.writePacketsLeft-- + } else { + t.requestKeyExchange() + } + + if err := t.pushPacket(p); err != nil { + t.writeError = err + } + + return nil +} + +func (t *handshakeTransport) Close() error { + return t.conn.Close() +} + +func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error { + if debugHandshake { + log.Printf("%s entered key exchange", t.id()) + } + + otherInit := &kexInitMsg{} + if err := Unmarshal(otherInitPacket, otherInit); err != nil { + return err + } + + magics := handshakeMagics{ + clientVersion: t.clientVersion, + serverVersion: t.serverVersion, + clientKexInit: otherInitPacket, + serverKexInit: t.sentInitPacket, + } + + clientInit := otherInit + serverInit := t.sentInitMsg + if len(t.hostKeys) == 0 { + clientInit, serverInit = serverInit, clientInit + + magics.clientKexInit = t.sentInitPacket + magics.serverKexInit = otherInitPacket + } + + var err error + t.algorithms, err = findAgreedAlgorithms(clientInit, serverInit) + if err != nil { + return err + } + + // We don't send FirstKexFollows, but we handle receiving it. + // + // RFC 4253 section 7 defines the kex and the agreement method for + // first_kex_packet_follows. It states that the guessed packet + // should be ignored if the "kex algorithm and/or the host + // key algorithm is guessed wrong (server and client have + // different preferred algorithm), or if any of the other + // algorithms cannot be agreed upon". The other algorithms have + // already been checked above so the kex algorithm and host key + // algorithm are checked here. + if otherInit.FirstKexFollows && (clientInit.KexAlgos[0] != serverInit.KexAlgos[0] || clientInit.ServerHostKeyAlgos[0] != serverInit.ServerHostKeyAlgos[0]) { + // other side sent a kex message for the wrong algorithm, + // which we have to ignore. + if _, err := t.conn.readPacket(); err != nil { + return err + } + } + + kex, ok := kexAlgoMap[t.algorithms.kex] + if !ok { + return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex) + } + + var result *kexResult + if len(t.hostKeys) > 0 { + result, err = t.server(kex, t.algorithms, &magics) + } else { + result, err = t.client(kex, t.algorithms, &magics) + } + + if err != nil { + return err + } + + if t.sessionID == nil { + t.sessionID = result.H + } + result.SessionID = t.sessionID + + if err := t.conn.prepareKeyChange(t.algorithms, result); err != nil { + return err + } + if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil { + return err + } + if packet, err := t.conn.readPacket(); err != nil { + return err + } else if packet[0] != msgNewKeys { + return unexpectedMessageError(msgNewKeys, packet[0]) + } + + return nil +} + +func (t *handshakeTransport) server(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) { + var hostKey Signer + for _, k := range t.hostKeys { + if algs.hostKey == k.PublicKey().Type() { + hostKey = k + } + } + + r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey) + return r, err +} + +func (t *handshakeTransport) client(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) { + result, err := kex.Client(t.conn, t.config.Rand, magics) + if err != nil { + return nil, err + } + + hostKey, err := ParsePublicKey(result.HostKey) + if err != nil { + return nil, err + } + + if err := verifyHostKeySignature(hostKey, result); err != nil { + return nil, err + } + + err = t.hostKeyCallback(t.dialAddress, t.remoteAddr, hostKey) + if err != nil { + return nil, err + } + + return result, nil +} diff --git a/vendor/golang.org/x/crypto/ssh/kex.go b/vendor/golang.org/x/crypto/ssh/kex.go new file mode 100644 index 00000000..f34bcc01 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/kex.go @@ -0,0 +1,540 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "crypto" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "crypto/subtle" + "errors" + "io" + "math/big" + + "golang.org/x/crypto/curve25519" +) + +const ( + kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1" + kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1" + kexAlgoECDH256 = "ecdh-sha2-nistp256" + kexAlgoECDH384 = "ecdh-sha2-nistp384" + kexAlgoECDH521 = "ecdh-sha2-nistp521" + kexAlgoCurve25519SHA256 = "curve25519-sha256@libssh.org" +) + +// kexResult captures the outcome of a key exchange. +type kexResult struct { + // Session hash. See also RFC 4253, section 8. + H []byte + + // Shared secret. See also RFC 4253, section 8. + K []byte + + // Host key as hashed into H. + HostKey []byte + + // Signature of H. + Signature []byte + + // A cryptographic hash function that matches the security + // level of the key exchange algorithm. It is used for + // calculating H, and for deriving keys from H and K. + Hash crypto.Hash + + // The session ID, which is the first H computed. This is used + // to derive key material inside the transport. + SessionID []byte +} + +// handshakeMagics contains data that is always included in the +// session hash. +type handshakeMagics struct { + clientVersion, serverVersion []byte + clientKexInit, serverKexInit []byte +} + +func (m *handshakeMagics) write(w io.Writer) { + writeString(w, m.clientVersion) + writeString(w, m.serverVersion) + writeString(w, m.clientKexInit) + writeString(w, m.serverKexInit) +} + +// kexAlgorithm abstracts different key exchange algorithms. +type kexAlgorithm interface { + // Server runs server-side key agreement, signing the result + // with a hostkey. + Server(p packetConn, rand io.Reader, magics *handshakeMagics, s Signer) (*kexResult, error) + + // Client runs the client-side key agreement. Caller is + // responsible for verifying the host key signature. + Client(p packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) +} + +// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement. +type dhGroup struct { + g, p, pMinus1 *big.Int +} + +func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) { + if theirPublic.Cmp(bigOne) <= 0 || theirPublic.Cmp(group.pMinus1) >= 0 { + return nil, errors.New("ssh: DH parameter out of bounds") + } + return new(big.Int).Exp(theirPublic, myPrivate, group.p), nil +} + +func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) { + hashFunc := crypto.SHA1 + + var x *big.Int + for { + var err error + if x, err = rand.Int(randSource, group.pMinus1); err != nil { + return nil, err + } + if x.Sign() > 0 { + break + } + } + + X := new(big.Int).Exp(group.g, x, group.p) + kexDHInit := kexDHInitMsg{ + X: X, + } + if err := c.writePacket(Marshal(&kexDHInit)); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var kexDHReply kexDHReplyMsg + if err = Unmarshal(packet, &kexDHReply); err != nil { + return nil, err + } + + ki, err := group.diffieHellman(kexDHReply.Y, x) + if err != nil { + return nil, err + } + + h := hashFunc.New() + magics.write(h) + writeString(h, kexDHReply.HostKey) + writeInt(h, X) + writeInt(h, kexDHReply.Y) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: kexDHReply.HostKey, + Signature: kexDHReply.Signature, + Hash: crypto.SHA1, + }, nil +} + +func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { + hashFunc := crypto.SHA1 + packet, err := c.readPacket() + if err != nil { + return + } + var kexDHInit kexDHInitMsg + if err = Unmarshal(packet, &kexDHInit); err != nil { + return + } + + var y *big.Int + for { + if y, err = rand.Int(randSource, group.pMinus1); err != nil { + return + } + if y.Sign() > 0 { + break + } + } + + Y := new(big.Int).Exp(group.g, y, group.p) + ki, err := group.diffieHellman(kexDHInit.X, y) + if err != nil { + return nil, err + } + + hostKeyBytes := priv.PublicKey().Marshal() + + h := hashFunc.New() + magics.write(h) + writeString(h, hostKeyBytes) + writeInt(h, kexDHInit.X) + writeInt(h, Y) + + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + H := h.Sum(nil) + + // H is already a hash, but the hostkey signing will apply its + // own key-specific hash algorithm. + sig, err := signAndMarshal(priv, randSource, H) + if err != nil { + return nil, err + } + + kexDHReply := kexDHReplyMsg{ + HostKey: hostKeyBytes, + Y: Y, + Signature: sig, + } + packet = Marshal(&kexDHReply) + + err = c.writePacket(packet) + return &kexResult{ + H: H, + K: K, + HostKey: hostKeyBytes, + Signature: sig, + Hash: crypto.SHA1, + }, nil +} + +// ecdh performs Elliptic Curve Diffie-Hellman key exchange as +// described in RFC 5656, section 4. +type ecdh struct { + curve elliptic.Curve +} + +func (kex *ecdh) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { + ephKey, err := ecdsa.GenerateKey(kex.curve, rand) + if err != nil { + return nil, err + } + + kexInit := kexECDHInitMsg{ + ClientPubKey: elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y), + } + + serialized := Marshal(&kexInit) + if err := c.writePacket(serialized); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var reply kexECDHReplyMsg + if err = Unmarshal(packet, &reply); err != nil { + return nil, err + } + + x, y, err := unmarshalECKey(kex.curve, reply.EphemeralPubKey) + if err != nil { + return nil, err + } + + // generate shared secret + secret, _ := kex.curve.ScalarMult(x, y, ephKey.D.Bytes()) + + h := ecHash(kex.curve).New() + magics.write(h) + writeString(h, reply.HostKey) + writeString(h, kexInit.ClientPubKey) + writeString(h, reply.EphemeralPubKey) + K := make([]byte, intLength(secret)) + marshalInt(K, secret) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: reply.HostKey, + Signature: reply.Signature, + Hash: ecHash(kex.curve), + }, nil +} + +// unmarshalECKey parses and checks an EC key. +func unmarshalECKey(curve elliptic.Curve, pubkey []byte) (x, y *big.Int, err error) { + x, y = elliptic.Unmarshal(curve, pubkey) + if x == nil { + return nil, nil, errors.New("ssh: elliptic.Unmarshal failure") + } + if !validateECPublicKey(curve, x, y) { + return nil, nil, errors.New("ssh: public key not on curve") + } + return x, y, nil +} + +// validateECPublicKey checks that the point is a valid public key for +// the given curve. See [SEC1], 3.2.2 +func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool { + if x.Sign() == 0 && y.Sign() == 0 { + return false + } + + if x.Cmp(curve.Params().P) >= 0 { + return false + } + + if y.Cmp(curve.Params().P) >= 0 { + return false + } + + if !curve.IsOnCurve(x, y) { + return false + } + + // We don't check if N * PubKey == 0, since + // + // - the NIST curves have cofactor = 1, so this is implicit. + // (We don't foresee an implementation that supports non NIST + // curves) + // + // - for ephemeral keys, we don't need to worry about small + // subgroup attacks. + return true +} + +func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var kexECDHInit kexECDHInitMsg + if err = Unmarshal(packet, &kexECDHInit); err != nil { + return nil, err + } + + clientX, clientY, err := unmarshalECKey(kex.curve, kexECDHInit.ClientPubKey) + if err != nil { + return nil, err + } + + // We could cache this key across multiple users/multiple + // connection attempts, but the benefit is small. OpenSSH + // generates a new key for each incoming connection. + ephKey, err := ecdsa.GenerateKey(kex.curve, rand) + if err != nil { + return nil, err + } + + hostKeyBytes := priv.PublicKey().Marshal() + + serializedEphKey := elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y) + + // generate shared secret + secret, _ := kex.curve.ScalarMult(clientX, clientY, ephKey.D.Bytes()) + + h := ecHash(kex.curve).New() + magics.write(h) + writeString(h, hostKeyBytes) + writeString(h, kexECDHInit.ClientPubKey) + writeString(h, serializedEphKey) + + K := make([]byte, intLength(secret)) + marshalInt(K, secret) + h.Write(K) + + H := h.Sum(nil) + + // H is already a hash, but the hostkey signing will apply its + // own key-specific hash algorithm. + sig, err := signAndMarshal(priv, rand, H) + if err != nil { + return nil, err + } + + reply := kexECDHReplyMsg{ + EphemeralPubKey: serializedEphKey, + HostKey: hostKeyBytes, + Signature: sig, + } + + serialized := Marshal(&reply) + if err := c.writePacket(serialized); err != nil { + return nil, err + } + + return &kexResult{ + H: H, + K: K, + HostKey: reply.HostKey, + Signature: sig, + Hash: ecHash(kex.curve), + }, nil +} + +var kexAlgoMap = map[string]kexAlgorithm{} + +func init() { + // This is the group called diffie-hellman-group1-sha1 in RFC + // 4253 and Oakley Group 2 in RFC 2409. + p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16) + kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + } + + // This is the group called diffie-hellman-group14-sha1 in RFC + // 4253 and Oakley Group 14 in RFC 3526. + p, _ = new(big.Int).SetString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kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{ + g: new(big.Int).SetInt64(2), + p: p, + pMinus1: new(big.Int).Sub(p, bigOne), + } + + kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()} + kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()} + kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()} + kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{} +} + +// curve25519sha256 implements the curve25519-sha256@libssh.org key +// agreement protocol, as described in +// https://git.libssh.org/projects/libssh.git/tree/doc/curve25519-sha256@libssh.org.txt +type curve25519sha256 struct{} + +type curve25519KeyPair struct { + priv [32]byte + pub [32]byte +} + +func (kp *curve25519KeyPair) generate(rand io.Reader) error { + if _, err := io.ReadFull(rand, kp.priv[:]); err != nil { + return err + } + curve25519.ScalarBaseMult(&kp.pub, &kp.priv) + return nil +} + +// curve25519Zeros is just an array of 32 zero bytes so that we have something +// convenient to compare against in order to reject curve25519 points with the +// wrong order. +var curve25519Zeros [32]byte + +func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) { + var kp curve25519KeyPair + if err := kp.generate(rand); err != nil { + return nil, err + } + if err := c.writePacket(Marshal(&kexECDHInitMsg{kp.pub[:]})); err != nil { + return nil, err + } + + packet, err := c.readPacket() + if err != nil { + return nil, err + } + + var reply kexECDHReplyMsg + if err = Unmarshal(packet, &reply); err != nil { + return nil, err + } + if len(reply.EphemeralPubKey) != 32 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong length") + } + + var servPub, secret [32]byte + copy(servPub[:], reply.EphemeralPubKey) + curve25519.ScalarMult(&secret, &kp.priv, &servPub) + if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong order") + } + + h := crypto.SHA256.New() + magics.write(h) + writeString(h, reply.HostKey) + writeString(h, kp.pub[:]) + writeString(h, reply.EphemeralPubKey) + + ki := new(big.Int).SetBytes(secret[:]) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + return &kexResult{ + H: h.Sum(nil), + K: K, + HostKey: reply.HostKey, + Signature: reply.Signature, + Hash: crypto.SHA256, + }, nil +} + +func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) { + packet, err := c.readPacket() + if err != nil { + return + } + var kexInit kexECDHInitMsg + if err = Unmarshal(packet, &kexInit); err != nil { + return + } + + if len(kexInit.ClientPubKey) != 32 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong length") + } + + var kp curve25519KeyPair + if err := kp.generate(rand); err != nil { + return nil, err + } + + var clientPub, secret [32]byte + copy(clientPub[:], kexInit.ClientPubKey) + curve25519.ScalarMult(&secret, &kp.priv, &clientPub) + if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 { + return nil, errors.New("ssh: peer's curve25519 public value has wrong order") + } + + hostKeyBytes := priv.PublicKey().Marshal() + + h := crypto.SHA256.New() + magics.write(h) + writeString(h, hostKeyBytes) + writeString(h, kexInit.ClientPubKey) + writeString(h, kp.pub[:]) + + ki := new(big.Int).SetBytes(secret[:]) + K := make([]byte, intLength(ki)) + marshalInt(K, ki) + h.Write(K) + + H := h.Sum(nil) + + sig, err := signAndMarshal(priv, rand, H) + if err != nil { + return nil, err + } + + reply := kexECDHReplyMsg{ + EphemeralPubKey: kp.pub[:], + HostKey: hostKeyBytes, + Signature: sig, + } + if err := c.writePacket(Marshal(&reply)); err != nil { + return nil, err + } + return &kexResult{ + H: H, + K: K, + HostKey: hostKeyBytes, + Signature: sig, + Hash: crypto.SHA256, + }, nil +} diff --git a/vendor/golang.org/x/crypto/ssh/keys.go b/vendor/golang.org/x/crypto/ssh/keys.go new file mode 100644 index 00000000..96980479 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/keys.go @@ -0,0 +1,1100 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "crypto" + "crypto/dsa" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/md5" + "crypto/rsa" + "crypto/sha256" + "crypto/x509" + "encoding/asn1" + "encoding/base64" + "encoding/hex" + "encoding/pem" + "errors" + "fmt" + "io" + "math/big" + "strings" + + "golang.org/x/crypto/ed25519" +) + +// These constants represent the algorithm names for key types supported by this +// package. +const ( + KeyAlgoRSA = "ssh-rsa" + KeyAlgoDSA = "ssh-dss" + KeyAlgoECDSA256 = "ecdsa-sha2-nistp256" + KeyAlgoECDSA384 = "ecdsa-sha2-nistp384" + KeyAlgoECDSA521 = "ecdsa-sha2-nistp521" + KeyAlgoED25519 = "ssh-ed25519" +) + +// These constants represent non-default signature algorithms that are supported +// as algorithm parameters to AlgorithmSigner.SignWithAlgorithm methods. See +// [PROTOCOL.agent] section 4.5.1 and +// https://tools.ietf.org/html/draft-ietf-curdle-rsa-sha2-10 +const ( + SigAlgoRSA = "ssh-rsa" + SigAlgoRSASHA2256 = "rsa-sha2-256" + SigAlgoRSASHA2512 = "rsa-sha2-512" +) + +// parsePubKey parses a public key of the given algorithm. +// Use ParsePublicKey for keys with prepended algorithm. +func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err error) { + switch algo { + case KeyAlgoRSA: + return parseRSA(in) + case KeyAlgoDSA: + return parseDSA(in) + case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521: + return parseECDSA(in) + case KeyAlgoED25519: + return parseED25519(in) + case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01: + cert, err := parseCert(in, certToPrivAlgo(algo)) + if err != nil { + return nil, nil, err + } + return cert, nil, nil + } + return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", algo) +} + +// parseAuthorizedKey parses a public key in OpenSSH authorized_keys format +// (see sshd(8) manual page) once the options and key type fields have been +// removed. +func parseAuthorizedKey(in []byte) (out PublicKey, comment string, err error) { + in = bytes.TrimSpace(in) + + i := bytes.IndexAny(in, " \t") + if i == -1 { + i = len(in) + } + base64Key := in[:i] + + key := make([]byte, base64.StdEncoding.DecodedLen(len(base64Key))) + n, err := base64.StdEncoding.Decode(key, base64Key) + if err != nil { + return nil, "", err + } + key = key[:n] + out, err = ParsePublicKey(key) + if err != nil { + return nil, "", err + } + comment = string(bytes.TrimSpace(in[i:])) + return out, comment, nil +} + +// ParseKnownHosts parses an entry in the format of the known_hosts file. +// +// The known_hosts format is documented in the sshd(8) manual page. This +// function will parse a single entry from in. On successful return, marker +// will contain the optional marker value (i.e. "cert-authority" or "revoked") +// or else be empty, hosts will contain the hosts that this entry matches, +// pubKey will contain the public key and comment will contain any trailing +// comment at the end of the line. See the sshd(8) manual page for the various +// forms that a host string can take. +// +// The unparsed remainder of the input will be returned in rest. This function +// can be called repeatedly to parse multiple entries. +// +// If no entries were found in the input then err will be io.EOF. Otherwise a +// non-nil err value indicates a parse error. +func ParseKnownHosts(in []byte) (marker string, hosts []string, pubKey PublicKey, comment string, rest []byte, err error) { + for len(in) > 0 { + end := bytes.IndexByte(in, '\n') + if end != -1 { + rest = in[end+1:] + in = in[:end] + } else { + rest = nil + } + + end = bytes.IndexByte(in, '\r') + if end != -1 { + in = in[:end] + } + + in = bytes.TrimSpace(in) + if len(in) == 0 || in[0] == '#' { + in = rest + continue + } + + i := bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + // Strip out the beginning of the known_host key. + // This is either an optional marker or a (set of) hostname(s). + keyFields := bytes.Fields(in) + if len(keyFields) < 3 || len(keyFields) > 5 { + return "", nil, nil, "", nil, errors.New("ssh: invalid entry in known_hosts data") + } + + // keyFields[0] is either "@cert-authority", "@revoked" or a comma separated + // list of hosts + marker := "" + if keyFields[0][0] == '@' { + marker = string(keyFields[0][1:]) + keyFields = keyFields[1:] + } + + hosts := string(keyFields[0]) + // keyFields[1] contains the key type (e.g. “ssh-rsa”). + // However, that information is duplicated inside the + // base64-encoded key and so is ignored here. + + key := bytes.Join(keyFields[2:], []byte(" ")) + if pubKey, comment, err = parseAuthorizedKey(key); err != nil { + return "", nil, nil, "", nil, err + } + + return marker, strings.Split(hosts, ","), pubKey, comment, rest, nil + } + + return "", nil, nil, "", nil, io.EOF +} + +// ParseAuthorizedKeys parses a public key from an authorized_keys +// file used in OpenSSH according to the sshd(8) manual page. +func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) { + for len(in) > 0 { + end := bytes.IndexByte(in, '\n') + if end != -1 { + rest = in[end+1:] + in = in[:end] + } else { + rest = nil + } + + end = bytes.IndexByte(in, '\r') + if end != -1 { + in = in[:end] + } + + in = bytes.TrimSpace(in) + if len(in) == 0 || in[0] == '#' { + in = rest + continue + } + + i := bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + if out, comment, err = parseAuthorizedKey(in[i:]); err == nil { + return out, comment, options, rest, nil + } + + // No key type recognised. Maybe there's an options field at + // the beginning. + var b byte + inQuote := false + var candidateOptions []string + optionStart := 0 + for i, b = range in { + isEnd := !inQuote && (b == ' ' || b == '\t') + if (b == ',' && !inQuote) || isEnd { + if i-optionStart > 0 { + candidateOptions = append(candidateOptions, string(in[optionStart:i])) + } + optionStart = i + 1 + } + if isEnd { + break + } + if b == '"' && (i == 0 || (i > 0 && in[i-1] != '\\')) { + inQuote = !inQuote + } + } + for i < len(in) && (in[i] == ' ' || in[i] == '\t') { + i++ + } + if i == len(in) { + // Invalid line: unmatched quote + in = rest + continue + } + + in = in[i:] + i = bytes.IndexAny(in, " \t") + if i == -1 { + in = rest + continue + } + + if out, comment, err = parseAuthorizedKey(in[i:]); err == nil { + options = candidateOptions + return out, comment, options, rest, nil + } + + in = rest + continue + } + + return nil, "", nil, nil, errors.New("ssh: no key found") +} + +// ParsePublicKey parses an SSH public key formatted for use in +// the SSH wire protocol according to RFC 4253, section 6.6. +func ParsePublicKey(in []byte) (out PublicKey, err error) { + algo, in, ok := parseString(in) + if !ok { + return nil, errShortRead + } + var rest []byte + out, rest, err = parsePubKey(in, string(algo)) + if len(rest) > 0 { + return nil, errors.New("ssh: trailing junk in public key") + } + + return out, err +} + +// MarshalAuthorizedKey serializes key for inclusion in an OpenSSH +// authorized_keys file. The return value ends with newline. +func MarshalAuthorizedKey(key PublicKey) []byte { + b := &bytes.Buffer{} + b.WriteString(key.Type()) + b.WriteByte(' ') + e := base64.NewEncoder(base64.StdEncoding, b) + e.Write(key.Marshal()) + e.Close() + b.WriteByte('\n') + return b.Bytes() +} + +// PublicKey is an abstraction of different types of public keys. +type PublicKey interface { + // Type returns the key's type, e.g. "ssh-rsa". + Type() string + + // Marshal returns the serialized key data in SSH wire format, + // with the name prefix. To unmarshal the returned data, use + // the ParsePublicKey function. + Marshal() []byte + + // Verify that sig is a signature on the given data using this + // key. This function will hash the data appropriately first. + Verify(data []byte, sig *Signature) error +} + +// CryptoPublicKey, if implemented by a PublicKey, +// returns the underlying crypto.PublicKey form of the key. +type CryptoPublicKey interface { + CryptoPublicKey() crypto.PublicKey +} + +// A Signer can create signatures that verify against a public key. +type Signer interface { + // PublicKey returns an associated PublicKey instance. + PublicKey() PublicKey + + // Sign returns raw signature for the given data. This method + // will apply the hash specified for the keytype to the data. + Sign(rand io.Reader, data []byte) (*Signature, error) +} + +// A AlgorithmSigner is a Signer that also supports specifying a specific +// algorithm to use for signing. +type AlgorithmSigner interface { + Signer + + // SignWithAlgorithm is like Signer.Sign, but allows specification of a + // non-default signing algorithm. See the SigAlgo* constants in this + // package for signature algorithms supported by this package. Callers may + // pass an empty string for the algorithm in which case the AlgorithmSigner + // will use its default algorithm. + SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) +} + +type rsaPublicKey rsa.PublicKey + +func (r *rsaPublicKey) Type() string { + return "ssh-rsa" +} + +// parseRSA parses an RSA key according to RFC 4253, section 6.6. +func parseRSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + E *big.Int + N *big.Int + Rest []byte `ssh:"rest"` + } + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + if w.E.BitLen() > 24 { + return nil, nil, errors.New("ssh: exponent too large") + } + e := w.E.Int64() + if e < 3 || e&1 == 0 { + return nil, nil, errors.New("ssh: incorrect exponent") + } + + var key rsa.PublicKey + key.E = int(e) + key.N = w.N + return (*rsaPublicKey)(&key), w.Rest, nil +} + +func (r *rsaPublicKey) Marshal() []byte { + e := new(big.Int).SetInt64(int64(r.E)) + // RSA publickey struct layout should match the struct used by + // parseRSACert in the x/crypto/ssh/agent package. + wirekey := struct { + Name string + E *big.Int + N *big.Int + }{ + KeyAlgoRSA, + e, + r.N, + } + return Marshal(&wirekey) +} + +func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error { + var hash crypto.Hash + switch sig.Format { + case SigAlgoRSA: + hash = crypto.SHA1 + case SigAlgoRSASHA2256: + hash = crypto.SHA256 + case SigAlgoRSASHA2512: + hash = crypto.SHA512 + default: + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type()) + } + h := hash.New() + h.Write(data) + digest := h.Sum(nil) + return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, sig.Blob) +} + +func (r *rsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*rsa.PublicKey)(r) +} + +type dsaPublicKey dsa.PublicKey + +func (k *dsaPublicKey) Type() string { + return "ssh-dss" +} + +func checkDSAParams(param *dsa.Parameters) error { + // SSH specifies FIPS 186-2, which only provided a single size + // (1024 bits) DSA key. FIPS 186-3 allows for larger key + // sizes, which would confuse SSH. + if l := param.P.BitLen(); l != 1024 { + return fmt.Errorf("ssh: unsupported DSA key size %d", l) + } + + return nil +} + +// parseDSA parses an DSA key according to RFC 4253, section 6.6. +func parseDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + P, Q, G, Y *big.Int + Rest []byte `ssh:"rest"` + } + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + param := dsa.Parameters{ + P: w.P, + Q: w.Q, + G: w.G, + } + if err := checkDSAParams(¶m); err != nil { + return nil, nil, err + } + + key := &dsaPublicKey{ + Parameters: param, + Y: w.Y, + } + return key, w.Rest, nil +} + +func (k *dsaPublicKey) Marshal() []byte { + // DSA publickey struct layout should match the struct used by + // parseDSACert in the x/crypto/ssh/agent package. + w := struct { + Name string + P, Q, G, Y *big.Int + }{ + k.Type(), + k.P, + k.Q, + k.G, + k.Y, + } + + return Marshal(&w) +} + +func (k *dsaPublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + h := crypto.SHA1.New() + h.Write(data) + digest := h.Sum(nil) + + // Per RFC 4253, section 6.6, + // The value for 'dss_signature_blob' is encoded as a string containing + // r, followed by s (which are 160-bit integers, without lengths or + // padding, unsigned, and in network byte order). + // For DSS purposes, sig.Blob should be exactly 40 bytes in length. + if len(sig.Blob) != 40 { + return errors.New("ssh: DSA signature parse error") + } + r := new(big.Int).SetBytes(sig.Blob[:20]) + s := new(big.Int).SetBytes(sig.Blob[20:]) + if dsa.Verify((*dsa.PublicKey)(k), digest, r, s) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +func (k *dsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*dsa.PublicKey)(k) +} + +type dsaPrivateKey struct { + *dsa.PrivateKey +} + +func (k *dsaPrivateKey) PublicKey() PublicKey { + return (*dsaPublicKey)(&k.PrivateKey.PublicKey) +} + +func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) { + return k.SignWithAlgorithm(rand, data, "") +} + +func (k *dsaPrivateKey) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + if algorithm != "" && algorithm != k.PublicKey().Type() { + return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm) + } + + h := crypto.SHA1.New() + h.Write(data) + digest := h.Sum(nil) + r, s, err := dsa.Sign(rand, k.PrivateKey, digest) + if err != nil { + return nil, err + } + + sig := make([]byte, 40) + rb := r.Bytes() + sb := s.Bytes() + + copy(sig[20-len(rb):20], rb) + copy(sig[40-len(sb):], sb) + + return &Signature{ + Format: k.PublicKey().Type(), + Blob: sig, + }, nil +} + +type ecdsaPublicKey ecdsa.PublicKey + +func (k *ecdsaPublicKey) Type() string { + return "ecdsa-sha2-" + k.nistID() +} + +func (k *ecdsaPublicKey) nistID() string { + switch k.Params().BitSize { + case 256: + return "nistp256" + case 384: + return "nistp384" + case 521: + return "nistp521" + } + panic("ssh: unsupported ecdsa key size") +} + +type ed25519PublicKey ed25519.PublicKey + +func (k ed25519PublicKey) Type() string { + return KeyAlgoED25519 +} + +func parseED25519(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + KeyBytes []byte + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + key := ed25519.PublicKey(w.KeyBytes) + + return (ed25519PublicKey)(key), w.Rest, nil +} + +func (k ed25519PublicKey) Marshal() []byte { + w := struct { + Name string + KeyBytes []byte + }{ + KeyAlgoED25519, + []byte(k), + } + return Marshal(&w) +} + +func (k ed25519PublicKey) Verify(b []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + + edKey := (ed25519.PublicKey)(k) + if ok := ed25519.Verify(edKey, b, sig.Blob); !ok { + return errors.New("ssh: signature did not verify") + } + + return nil +} + +func (k ed25519PublicKey) CryptoPublicKey() crypto.PublicKey { + return ed25519.PublicKey(k) +} + +func supportedEllipticCurve(curve elliptic.Curve) bool { + return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521() +} + +// ecHash returns the hash to match the given elliptic curve, see RFC +// 5656, section 6.2.1 +func ecHash(curve elliptic.Curve) crypto.Hash { + bitSize := curve.Params().BitSize + switch { + case bitSize <= 256: + return crypto.SHA256 + case bitSize <= 384: + return crypto.SHA384 + } + return crypto.SHA512 +} + +// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1. +func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) { + var w struct { + Curve string + KeyBytes []byte + Rest []byte `ssh:"rest"` + } + + if err := Unmarshal(in, &w); err != nil { + return nil, nil, err + } + + key := new(ecdsa.PublicKey) + + switch w.Curve { + case "nistp256": + key.Curve = elliptic.P256() + case "nistp384": + key.Curve = elliptic.P384() + case "nistp521": + key.Curve = elliptic.P521() + default: + return nil, nil, errors.New("ssh: unsupported curve") + } + + key.X, key.Y = elliptic.Unmarshal(key.Curve, w.KeyBytes) + if key.X == nil || key.Y == nil { + return nil, nil, errors.New("ssh: invalid curve point") + } + return (*ecdsaPublicKey)(key), w.Rest, nil +} + +func (k *ecdsaPublicKey) Marshal() []byte { + // See RFC 5656, section 3.1. + keyBytes := elliptic.Marshal(k.Curve, k.X, k.Y) + // ECDSA publickey struct layout should match the struct used by + // parseECDSACert in the x/crypto/ssh/agent package. + w := struct { + Name string + ID string + Key []byte + }{ + k.Type(), + k.nistID(), + keyBytes, + } + + return Marshal(&w) +} + +func (k *ecdsaPublicKey) Verify(data []byte, sig *Signature) error { + if sig.Format != k.Type() { + return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type()) + } + + h := ecHash(k.Curve).New() + h.Write(data) + digest := h.Sum(nil) + + // Per RFC 5656, section 3.1.2, + // The ecdsa_signature_blob value has the following specific encoding: + // mpint r + // mpint s + var ecSig struct { + R *big.Int + S *big.Int + } + + if err := Unmarshal(sig.Blob, &ecSig); err != nil { + return err + } + + if ecdsa.Verify((*ecdsa.PublicKey)(k), digest, ecSig.R, ecSig.S) { + return nil + } + return errors.New("ssh: signature did not verify") +} + +func (k *ecdsaPublicKey) CryptoPublicKey() crypto.PublicKey { + return (*ecdsa.PublicKey)(k) +} + +// NewSignerFromKey takes an *rsa.PrivateKey, *dsa.PrivateKey, +// *ecdsa.PrivateKey or any other crypto.Signer and returns a +// corresponding Signer instance. ECDSA keys must use P-256, P-384 or +// P-521. DSA keys must use parameter size L1024N160. +func NewSignerFromKey(key interface{}) (Signer, error) { + switch key := key.(type) { + case crypto.Signer: + return NewSignerFromSigner(key) + case *dsa.PrivateKey: + return newDSAPrivateKey(key) + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", key) + } +} + +func newDSAPrivateKey(key *dsa.PrivateKey) (Signer, error) { + if err := checkDSAParams(&key.PublicKey.Parameters); err != nil { + return nil, err + } + + return &dsaPrivateKey{key}, nil +} + +type wrappedSigner struct { + signer crypto.Signer + pubKey PublicKey +} + +// NewSignerFromSigner takes any crypto.Signer implementation and +// returns a corresponding Signer interface. This can be used, for +// example, with keys kept in hardware modules. +func NewSignerFromSigner(signer crypto.Signer) (Signer, error) { + pubKey, err := NewPublicKey(signer.Public()) + if err != nil { + return nil, err + } + + return &wrappedSigner{signer, pubKey}, nil +} + +func (s *wrappedSigner) PublicKey() PublicKey { + return s.pubKey +} + +func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) { + return s.SignWithAlgorithm(rand, data, "") +} + +func (s *wrappedSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) { + var hashFunc crypto.Hash + + if _, ok := s.pubKey.(*rsaPublicKey); ok { + // RSA keys support a few hash functions determined by the requested signature algorithm + switch algorithm { + case "", SigAlgoRSA: + algorithm = SigAlgoRSA + hashFunc = crypto.SHA1 + case SigAlgoRSASHA2256: + hashFunc = crypto.SHA256 + case SigAlgoRSASHA2512: + hashFunc = crypto.SHA512 + default: + return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm) + } + } else { + // The only supported algorithm for all other key types is the same as the type of the key + if algorithm == "" { + algorithm = s.pubKey.Type() + } else if algorithm != s.pubKey.Type() { + return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm) + } + + switch key := s.pubKey.(type) { + case *dsaPublicKey: + hashFunc = crypto.SHA1 + case *ecdsaPublicKey: + hashFunc = ecHash(key.Curve) + case ed25519PublicKey: + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", key) + } + } + + var digest []byte + if hashFunc != 0 { + h := hashFunc.New() + h.Write(data) + digest = h.Sum(nil) + } else { + digest = data + } + + signature, err := s.signer.Sign(rand, digest, hashFunc) + if err != nil { + return nil, err + } + + // crypto.Signer.Sign is expected to return an ASN.1-encoded signature + // for ECDSA and DSA, but that's not the encoding expected by SSH, so + // re-encode. + switch s.pubKey.(type) { + case *ecdsaPublicKey, *dsaPublicKey: + type asn1Signature struct { + R, S *big.Int + } + asn1Sig := new(asn1Signature) + _, err := asn1.Unmarshal(signature, asn1Sig) + if err != nil { + return nil, err + } + + switch s.pubKey.(type) { + case *ecdsaPublicKey: + signature = Marshal(asn1Sig) + + case *dsaPublicKey: + signature = make([]byte, 40) + r := asn1Sig.R.Bytes() + s := asn1Sig.S.Bytes() + copy(signature[20-len(r):20], r) + copy(signature[40-len(s):40], s) + } + } + + return &Signature{ + Format: algorithm, + Blob: signature, + }, nil +} + +// NewPublicKey takes an *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey, +// or ed25519.PublicKey returns a corresponding PublicKey instance. +// ECDSA keys must use P-256, P-384 or P-521. +func NewPublicKey(key interface{}) (PublicKey, error) { + switch key := key.(type) { + case *rsa.PublicKey: + return (*rsaPublicKey)(key), nil + case *ecdsa.PublicKey: + if !supportedEllipticCurve(key.Curve) { + return nil, errors.New("ssh: only P-256, P-384 and P-521 EC keys are supported") + } + return (*ecdsaPublicKey)(key), nil + case *dsa.PublicKey: + return (*dsaPublicKey)(key), nil + case ed25519.PublicKey: + return (ed25519PublicKey)(key), nil + default: + return nil, fmt.Errorf("ssh: unsupported key type %T", key) + } +} + +// ParsePrivateKey returns a Signer from a PEM encoded private key. It supports +// the same keys as ParseRawPrivateKey. +func ParsePrivateKey(pemBytes []byte) (Signer, error) { + key, err := ParseRawPrivateKey(pemBytes) + if err != nil { + return nil, err + } + + return NewSignerFromKey(key) +} + +// ParsePrivateKeyWithPassphrase returns a Signer from a PEM encoded private +// key and passphrase. It supports the same keys as +// ParseRawPrivateKeyWithPassphrase. +func ParsePrivateKeyWithPassphrase(pemBytes, passPhrase []byte) (Signer, error) { + key, err := ParseRawPrivateKeyWithPassphrase(pemBytes, passPhrase) + if err != nil { + return nil, err + } + + return NewSignerFromKey(key) +} + +// encryptedBlock tells whether a private key is +// encrypted by examining its Proc-Type header +// for a mention of ENCRYPTED +// according to RFC 1421 Section 4.6.1.1. +func encryptedBlock(block *pem.Block) bool { + return strings.Contains(block.Headers["Proc-Type"], "ENCRYPTED") +} + +// ParseRawPrivateKey returns a private key from a PEM encoded private key. It +// supports RSA (PKCS#1), PKCS#8, DSA (OpenSSL), and ECDSA private keys. +func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) { + block, _ := pem.Decode(pemBytes) + if block == nil { + return nil, errors.New("ssh: no key found") + } + + if encryptedBlock(block) { + return nil, errors.New("ssh: cannot decode encrypted private keys") + } + + switch block.Type { + case "RSA PRIVATE KEY": + return x509.ParsePKCS1PrivateKey(block.Bytes) + // RFC5208 - https://tools.ietf.org/html/rfc5208 + case "PRIVATE KEY": + return x509.ParsePKCS8PrivateKey(block.Bytes) + case "EC PRIVATE KEY": + return x509.ParseECPrivateKey(block.Bytes) + case "DSA PRIVATE KEY": + return ParseDSAPrivateKey(block.Bytes) + case "OPENSSH PRIVATE KEY": + return parseOpenSSHPrivateKey(block.Bytes) + default: + return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type) + } +} + +// ParseRawPrivateKeyWithPassphrase returns a private key decrypted with +// passphrase from a PEM encoded private key. If wrong passphrase, return +// x509.IncorrectPasswordError. +func ParseRawPrivateKeyWithPassphrase(pemBytes, passPhrase []byte) (interface{}, error) { + block, _ := pem.Decode(pemBytes) + if block == nil { + return nil, errors.New("ssh: no key found") + } + buf := block.Bytes + + if encryptedBlock(block) { + if x509.IsEncryptedPEMBlock(block) { + var err error + buf, err = x509.DecryptPEMBlock(block, passPhrase) + if err != nil { + if err == x509.IncorrectPasswordError { + return nil, err + } + return nil, fmt.Errorf("ssh: cannot decode encrypted private keys: %v", err) + } + } + } + + switch block.Type { + case "RSA PRIVATE KEY": + return x509.ParsePKCS1PrivateKey(buf) + case "EC PRIVATE KEY": + return x509.ParseECPrivateKey(buf) + case "DSA PRIVATE KEY": + return ParseDSAPrivateKey(buf) + case "OPENSSH PRIVATE KEY": + return parseOpenSSHPrivateKey(buf) + default: + return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type) + } +} + +// ParseDSAPrivateKey returns a DSA private key from its ASN.1 DER encoding, as +// specified by the OpenSSL DSA man page. +func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) { + var k struct { + Version int + P *big.Int + Q *big.Int + G *big.Int + Pub *big.Int + Priv *big.Int + } + rest, err := asn1.Unmarshal(der, &k) + if err != nil { + return nil, errors.New("ssh: failed to parse DSA key: " + err.Error()) + } + if len(rest) > 0 { + return nil, errors.New("ssh: garbage after DSA key") + } + + return &dsa.PrivateKey{ + PublicKey: dsa.PublicKey{ + Parameters: dsa.Parameters{ + P: k.P, + Q: k.Q, + G: k.G, + }, + Y: k.Pub, + }, + X: k.Priv, + }, nil +} + +// Implemented based on the documentation at +// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key +func parseOpenSSHPrivateKey(key []byte) (crypto.PrivateKey, error) { + const magic = "openssh-key-v1\x00" + if len(key) < len(magic) || string(key[:len(magic)]) != magic { + return nil, errors.New("ssh: invalid openssh private key format") + } + remaining := key[len(magic):] + + var w struct { + CipherName string + KdfName string + KdfOpts string + NumKeys uint32 + PubKey []byte + PrivKeyBlock []byte + } + + if err := Unmarshal(remaining, &w); err != nil { + return nil, err + } + + if w.KdfName != "none" || w.CipherName != "none" { + return nil, errors.New("ssh: cannot decode encrypted private keys") + } + + pk1 := struct { + Check1 uint32 + Check2 uint32 + Keytype string + Rest []byte `ssh:"rest"` + }{} + + if err := Unmarshal(w.PrivKeyBlock, &pk1); err != nil { + return nil, err + } + + if pk1.Check1 != pk1.Check2 { + return nil, errors.New("ssh: checkint mismatch") + } + + // we only handle ed25519 and rsa keys currently + switch pk1.Keytype { + case KeyAlgoRSA: + // https://github.com/openssh/openssh-portable/blob/master/sshkey.c#L2760-L2773 + key := struct { + N *big.Int + E *big.Int + D *big.Int + Iqmp *big.Int + P *big.Int + Q *big.Int + Comment string + Pad []byte `ssh:"rest"` + }{} + + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + for i, b := range key.Pad { + if int(b) != i+1 { + return nil, errors.New("ssh: padding not as expected") + } + } + + pk := &rsa.PrivateKey{ + PublicKey: rsa.PublicKey{ + N: key.N, + E: int(key.E.Int64()), + }, + D: key.D, + Primes: []*big.Int{key.P, key.Q}, + } + + if err := pk.Validate(); err != nil { + return nil, err + } + + pk.Precompute() + + return pk, nil + case KeyAlgoED25519: + key := struct { + Pub []byte + Priv []byte + Comment string + Pad []byte `ssh:"rest"` + }{} + + if err := Unmarshal(pk1.Rest, &key); err != nil { + return nil, err + } + + if len(key.Priv) != ed25519.PrivateKeySize { + return nil, errors.New("ssh: private key unexpected length") + } + + for i, b := range key.Pad { + if int(b) != i+1 { + return nil, errors.New("ssh: padding not as expected") + } + } + + pk := ed25519.PrivateKey(make([]byte, ed25519.PrivateKeySize)) + copy(pk, key.Priv) + return &pk, nil + default: + return nil, errors.New("ssh: unhandled key type") + } +} + +// FingerprintLegacyMD5 returns the user presentation of the key's +// fingerprint as described by RFC 4716 section 4. +func FingerprintLegacyMD5(pubKey PublicKey) string { + md5sum := md5.Sum(pubKey.Marshal()) + hexarray := make([]string, len(md5sum)) + for i, c := range md5sum { + hexarray[i] = hex.EncodeToString([]byte{c}) + } + return strings.Join(hexarray, ":") +} + +// FingerprintSHA256 returns the user presentation of the key's +// fingerprint as unpadded base64 encoded sha256 hash. +// This format was introduced from OpenSSH 6.8. +// https://www.openssh.com/txt/release-6.8 +// https://tools.ietf.org/html/rfc4648#section-3.2 (unpadded base64 encoding) +func FingerprintSHA256(pubKey PublicKey) string { + sha256sum := sha256.Sum256(pubKey.Marshal()) + hash := base64.RawStdEncoding.EncodeToString(sha256sum[:]) + return "SHA256:" + hash +} diff --git a/vendor/golang.org/x/crypto/ssh/mac.go b/vendor/golang.org/x/crypto/ssh/mac.go new file mode 100644 index 00000000..c07a0628 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/mac.go @@ -0,0 +1,61 @@ +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Message authentication support + +import ( + "crypto/hmac" + "crypto/sha1" + "crypto/sha256" + "hash" +) + +type macMode struct { + keySize int + etm bool + new func(key []byte) hash.Hash +} + +// truncatingMAC wraps around a hash.Hash and truncates the output digest to +// a given size. +type truncatingMAC struct { + length int + hmac hash.Hash +} + +func (t truncatingMAC) Write(data []byte) (int, error) { + return t.hmac.Write(data) +} + +func (t truncatingMAC) Sum(in []byte) []byte { + out := t.hmac.Sum(in) + return out[:len(in)+t.length] +} + +func (t truncatingMAC) Reset() { + t.hmac.Reset() +} + +func (t truncatingMAC) Size() int { + return t.length +} + +func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() } + +var macModes = map[string]*macMode{ + "hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash { + return hmac.New(sha256.New, key) + }}, + "hmac-sha2-256": {32, false, func(key []byte) hash.Hash { + return hmac.New(sha256.New, key) + }}, + "hmac-sha1": {20, false, func(key []byte) hash.Hash { + return hmac.New(sha1.New, key) + }}, + "hmac-sha1-96": {20, false, func(key []byte) hash.Hash { + return truncatingMAC{12, hmac.New(sha1.New, key)} + }}, +} diff --git a/vendor/golang.org/x/crypto/ssh/messages.go b/vendor/golang.org/x/crypto/ssh/messages.go new file mode 100644 index 00000000..5ec42afa --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/messages.go @@ -0,0 +1,792 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "math/big" + "reflect" + "strconv" + "strings" +) + +// These are SSH message type numbers. They are scattered around several +// documents but many were taken from [SSH-PARAMETERS]. +const ( + msgIgnore = 2 + msgUnimplemented = 3 + msgDebug = 4 + msgNewKeys = 21 +) + +// SSH messages: +// +// These structures mirror the wire format of the corresponding SSH messages. +// They are marshaled using reflection with the marshal and unmarshal functions +// in this file. The only wrinkle is that a final member of type []byte with a +// ssh tag of "rest" receives the remainder of a packet when unmarshaling. + +// See RFC 4253, section 11.1. +const msgDisconnect = 1 + +// disconnectMsg is the message that signals a disconnect. It is also +// the error type returned from mux.Wait() +type disconnectMsg struct { + Reason uint32 `sshtype:"1"` + Message string + Language string +} + +func (d *disconnectMsg) Error() string { + return fmt.Sprintf("ssh: disconnect, reason %d: %s", d.Reason, d.Message) +} + +// See RFC 4253, section 7.1. +const msgKexInit = 20 + +type kexInitMsg struct { + Cookie [16]byte `sshtype:"20"` + KexAlgos []string + ServerHostKeyAlgos []string + CiphersClientServer []string + CiphersServerClient []string + MACsClientServer []string + MACsServerClient []string + CompressionClientServer []string + CompressionServerClient []string + LanguagesClientServer []string + LanguagesServerClient []string + FirstKexFollows bool + Reserved uint32 +} + +// See RFC 4253, section 8. + +// Diffie-Helman +const msgKexDHInit = 30 + +type kexDHInitMsg struct { + X *big.Int `sshtype:"30"` +} + +const msgKexECDHInit = 30 + +type kexECDHInitMsg struct { + ClientPubKey []byte `sshtype:"30"` +} + +const msgKexECDHReply = 31 + +type kexECDHReplyMsg struct { + HostKey []byte `sshtype:"31"` + EphemeralPubKey []byte + Signature []byte +} + +const msgKexDHReply = 31 + +type kexDHReplyMsg struct { + HostKey []byte `sshtype:"31"` + Y *big.Int + Signature []byte +} + +// See RFC 4253, section 10. +const msgServiceRequest = 5 + +type serviceRequestMsg struct { + Service string `sshtype:"5"` +} + +// See RFC 4253, section 10. +const msgServiceAccept = 6 + +type serviceAcceptMsg struct { + Service string `sshtype:"6"` +} + +// See RFC 4252, section 5. +const msgUserAuthRequest = 50 + +type userAuthRequestMsg struct { + User string `sshtype:"50"` + Service string + Method string + Payload []byte `ssh:"rest"` +} + +// Used for debug printouts of packets. +type userAuthSuccessMsg struct { +} + +// See RFC 4252, section 5.1 +const msgUserAuthFailure = 51 + +type userAuthFailureMsg struct { + Methods []string `sshtype:"51"` + PartialSuccess bool +} + +// See RFC 4252, section 5.1 +const msgUserAuthSuccess = 52 + +// See RFC 4252, section 5.4 +const msgUserAuthBanner = 53 + +type userAuthBannerMsg struct { + Message string `sshtype:"53"` + // unused, but required to allow message parsing + Language string +} + +// See RFC 4256, section 3.2 +const msgUserAuthInfoRequest = 60 +const msgUserAuthInfoResponse = 61 + +type userAuthInfoRequestMsg struct { + User string `sshtype:"60"` + Instruction string + DeprecatedLanguage string + NumPrompts uint32 + Prompts []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpen = 90 + +type channelOpenMsg struct { + ChanType string `sshtype:"90"` + PeersID uint32 + PeersWindow uint32 + MaxPacketSize uint32 + TypeSpecificData []byte `ssh:"rest"` +} + +const msgChannelExtendedData = 95 +const msgChannelData = 94 + +// Used for debug print outs of packets. +type channelDataMsg struct { + PeersID uint32 `sshtype:"94"` + Length uint32 + Rest []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpenConfirm = 91 + +type channelOpenConfirmMsg struct { + PeersID uint32 `sshtype:"91"` + MyID uint32 + MyWindow uint32 + MaxPacketSize uint32 + TypeSpecificData []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.1. +const msgChannelOpenFailure = 92 + +type channelOpenFailureMsg struct { + PeersID uint32 `sshtype:"92"` + Reason RejectionReason + Message string + Language string +} + +const msgChannelRequest = 98 + +type channelRequestMsg struct { + PeersID uint32 `sshtype:"98"` + Request string + WantReply bool + RequestSpecificData []byte `ssh:"rest"` +} + +// See RFC 4254, section 5.4. +const msgChannelSuccess = 99 + +type channelRequestSuccessMsg struct { + PeersID uint32 `sshtype:"99"` +} + +// See RFC 4254, section 5.4. +const msgChannelFailure = 100 + +type channelRequestFailureMsg struct { + PeersID uint32 `sshtype:"100"` +} + +// See RFC 4254, section 5.3 +const msgChannelClose = 97 + +type channelCloseMsg struct { + PeersID uint32 `sshtype:"97"` +} + +// See RFC 4254, section 5.3 +const msgChannelEOF = 96 + +type channelEOFMsg struct { + PeersID uint32 `sshtype:"96"` +} + +// See RFC 4254, section 4 +const msgGlobalRequest = 80 + +type globalRequestMsg struct { + Type string `sshtype:"80"` + WantReply bool + Data []byte `ssh:"rest"` +} + +// See RFC 4254, section 4 +const msgRequestSuccess = 81 + +type globalRequestSuccessMsg struct { + Data []byte `ssh:"rest" sshtype:"81"` +} + +// See RFC 4254, section 4 +const msgRequestFailure = 82 + +type globalRequestFailureMsg struct { + Data []byte `ssh:"rest" sshtype:"82"` +} + +// See RFC 4254, section 5.2 +const msgChannelWindowAdjust = 93 + +type windowAdjustMsg struct { + PeersID uint32 `sshtype:"93"` + AdditionalBytes uint32 +} + +// See RFC 4252, section 7 +const msgUserAuthPubKeyOk = 60 + +type userAuthPubKeyOkMsg struct { + Algo string `sshtype:"60"` + PubKey []byte +} + +// typeTags returns the possible type bytes for the given reflect.Type, which +// should be a struct. The possible values are separated by a '|' character. +func typeTags(structType reflect.Type) (tags []byte) { + tagStr := structType.Field(0).Tag.Get("sshtype") + + for _, tag := range strings.Split(tagStr, "|") { + i, err := strconv.Atoi(tag) + if err == nil { + tags = append(tags, byte(i)) + } + } + + return tags +} + +func fieldError(t reflect.Type, field int, problem string) error { + if problem != "" { + problem = ": " + problem + } + return fmt.Errorf("ssh: unmarshal error for field %s of type %s%s", t.Field(field).Name, t.Name(), problem) +} + +var errShortRead = errors.New("ssh: short read") + +// Unmarshal parses data in SSH wire format into a structure. The out +// argument should be a pointer to struct. If the first member of the +// struct has the "sshtype" tag set to a '|'-separated set of numbers +// in decimal, the packet must start with one of those numbers. In +// case of error, Unmarshal returns a ParseError or +// UnexpectedMessageError. +func Unmarshal(data []byte, out interface{}) error { + v := reflect.ValueOf(out).Elem() + structType := v.Type() + expectedTypes := typeTags(structType) + + var expectedType byte + if len(expectedTypes) > 0 { + expectedType = expectedTypes[0] + } + + if len(data) == 0 { + return parseError(expectedType) + } + + if len(expectedTypes) > 0 { + goodType := false + for _, e := range expectedTypes { + if e > 0 && data[0] == e { + goodType = true + break + } + } + if !goodType { + return fmt.Errorf("ssh: unexpected message type %d (expected one of %v)", data[0], expectedTypes) + } + data = data[1:] + } + + var ok bool + for i := 0; i < v.NumField(); i++ { + field := v.Field(i) + t := field.Type() + switch t.Kind() { + case reflect.Bool: + if len(data) < 1 { + return errShortRead + } + field.SetBool(data[0] != 0) + data = data[1:] + case reflect.Array: + if t.Elem().Kind() != reflect.Uint8 { + return fieldError(structType, i, "array of unsupported type") + } + if len(data) < t.Len() { + return errShortRead + } + for j, n := 0, t.Len(); j < n; j++ { + field.Index(j).Set(reflect.ValueOf(data[j])) + } + data = data[t.Len():] + case reflect.Uint64: + var u64 uint64 + if u64, data, ok = parseUint64(data); !ok { + return errShortRead + } + field.SetUint(u64) + case reflect.Uint32: + var u32 uint32 + if u32, data, ok = parseUint32(data); !ok { + return errShortRead + } + field.SetUint(uint64(u32)) + case reflect.Uint8: + if len(data) < 1 { + return errShortRead + } + field.SetUint(uint64(data[0])) + data = data[1:] + case reflect.String: + var s []byte + if s, data, ok = parseString(data); !ok { + return fieldError(structType, i, "") + } + field.SetString(string(s)) + case reflect.Slice: + switch t.Elem().Kind() { + case reflect.Uint8: + if structType.Field(i).Tag.Get("ssh") == "rest" { + field.Set(reflect.ValueOf(data)) + data = nil + } else { + var s []byte + if s, data, ok = parseString(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(s)) + } + case reflect.String: + var nl []string + if nl, data, ok = parseNameList(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(nl)) + default: + return fieldError(structType, i, "slice of unsupported type") + } + case reflect.Ptr: + if t == bigIntType { + var n *big.Int + if n, data, ok = parseInt(data); !ok { + return errShortRead + } + field.Set(reflect.ValueOf(n)) + } else { + return fieldError(structType, i, "pointer to unsupported type") + } + default: + return fieldError(structType, i, fmt.Sprintf("unsupported type: %v", t)) + } + } + + if len(data) != 0 { + return parseError(expectedType) + } + + return nil +} + +// Marshal serializes the message in msg to SSH wire format. The msg +// argument should be a struct or pointer to struct. If the first +// member has the "sshtype" tag set to a number in decimal, that +// number is prepended to the result. If the last of member has the +// "ssh" tag set to "rest", its contents are appended to the output. +func Marshal(msg interface{}) []byte { + out := make([]byte, 0, 64) + return marshalStruct(out, msg) +} + +func marshalStruct(out []byte, msg interface{}) []byte { + v := reflect.Indirect(reflect.ValueOf(msg)) + msgTypes := typeTags(v.Type()) + if len(msgTypes) > 0 { + out = append(out, msgTypes[0]) + } + + for i, n := 0, v.NumField(); i < n; i++ { + field := v.Field(i) + switch t := field.Type(); t.Kind() { + case reflect.Bool: + var v uint8 + if field.Bool() { + v = 1 + } + out = append(out, v) + case reflect.Array: + if t.Elem().Kind() != reflect.Uint8 { + panic(fmt.Sprintf("array of non-uint8 in field %d: %T", i, field.Interface())) + } + for j, l := 0, t.Len(); j < l; j++ { + out = append(out, uint8(field.Index(j).Uint())) + } + case reflect.Uint32: + out = appendU32(out, uint32(field.Uint())) + case reflect.Uint64: + out = appendU64(out, uint64(field.Uint())) + case reflect.Uint8: + out = append(out, uint8(field.Uint())) + case reflect.String: + s := field.String() + out = appendInt(out, len(s)) + out = append(out, s...) + case reflect.Slice: + switch t.Elem().Kind() { + case reflect.Uint8: + if v.Type().Field(i).Tag.Get("ssh") != "rest" { + out = appendInt(out, field.Len()) + } + out = append(out, field.Bytes()...) + case reflect.String: + offset := len(out) + out = appendU32(out, 0) + if n := field.Len(); n > 0 { + for j := 0; j < n; j++ { + f := field.Index(j) + if j != 0 { + out = append(out, ',') + } + out = append(out, f.String()...) + } + // overwrite length value + binary.BigEndian.PutUint32(out[offset:], uint32(len(out)-offset-4)) + } + default: + panic(fmt.Sprintf("slice of unknown type in field %d: %T", i, field.Interface())) + } + case reflect.Ptr: + if t == bigIntType { + var n *big.Int + nValue := reflect.ValueOf(&n) + nValue.Elem().Set(field) + needed := intLength(n) + oldLength := len(out) + + if cap(out)-len(out) < needed { + newOut := make([]byte, len(out), 2*(len(out)+needed)) + copy(newOut, out) + out = newOut + } + out = out[:oldLength+needed] + marshalInt(out[oldLength:], n) + } else { + panic(fmt.Sprintf("pointer to unknown type in field %d: %T", i, field.Interface())) + } + } + } + + return out +} + +var bigOne = big.NewInt(1) + +func parseString(in []byte) (out, rest []byte, ok bool) { + if len(in) < 4 { + return + } + length := binary.BigEndian.Uint32(in) + in = in[4:] + if uint32(len(in)) < length { + return + } + out = in[:length] + rest = in[length:] + ok = true + return +} + +var ( + comma = []byte{','} + emptyNameList = []string{} +) + +func parseNameList(in []byte) (out []string, rest []byte, ok bool) { + contents, rest, ok := parseString(in) + if !ok { + return + } + if len(contents) == 0 { + out = emptyNameList + return + } + parts := bytes.Split(contents, comma) + out = make([]string, len(parts)) + for i, part := range parts { + out[i] = string(part) + } + return +} + +func parseInt(in []byte) (out *big.Int, rest []byte, ok bool) { + contents, rest, ok := parseString(in) + if !ok { + return + } + out = new(big.Int) + + if len(contents) > 0 && contents[0]&0x80 == 0x80 { + // This is a negative number + notBytes := make([]byte, len(contents)) + for i := range notBytes { + notBytes[i] = ^contents[i] + } + out.SetBytes(notBytes) + out.Add(out, bigOne) + out.Neg(out) + } else { + // Positive number + out.SetBytes(contents) + } + ok = true + return +} + +func parseUint32(in []byte) (uint32, []byte, bool) { + if len(in) < 4 { + return 0, nil, false + } + return binary.BigEndian.Uint32(in), in[4:], true +} + +func parseUint64(in []byte) (uint64, []byte, bool) { + if len(in) < 8 { + return 0, nil, false + } + return binary.BigEndian.Uint64(in), in[8:], true +} + +func intLength(n *big.Int) int { + length := 4 /* length bytes */ + if n.Sign() < 0 { + nMinus1 := new(big.Int).Neg(n) + nMinus1.Sub(nMinus1, bigOne) + bitLen := nMinus1.BitLen() + if bitLen%8 == 0 { + // The number will need 0xff padding + length++ + } + length += (bitLen + 7) / 8 + } else if n.Sign() == 0 { + // A zero is the zero length string + } else { + bitLen := n.BitLen() + if bitLen%8 == 0 { + // The number will need 0x00 padding + length++ + } + length += (bitLen + 7) / 8 + } + + return length +} + +func marshalUint32(to []byte, n uint32) []byte { + binary.BigEndian.PutUint32(to, n) + return to[4:] +} + +func marshalUint64(to []byte, n uint64) []byte { + binary.BigEndian.PutUint64(to, n) + return to[8:] +} + +func marshalInt(to []byte, n *big.Int) []byte { + lengthBytes := to + to = to[4:] + length := 0 + + if n.Sign() < 0 { + // A negative number has to be converted to two's-complement + // form. So we'll subtract 1 and invert. If the + // most-significant-bit isn't set then we'll need to pad the + // beginning with 0xff in order to keep the number negative. + nMinus1 := new(big.Int).Neg(n) + nMinus1.Sub(nMinus1, bigOne) + bytes := nMinus1.Bytes() + for i := range bytes { + bytes[i] ^= 0xff + } + if len(bytes) == 0 || bytes[0]&0x80 == 0 { + to[0] = 0xff + to = to[1:] + length++ + } + nBytes := copy(to, bytes) + to = to[nBytes:] + length += nBytes + } else if n.Sign() == 0 { + // A zero is the zero length string + } else { + bytes := n.Bytes() + if len(bytes) > 0 && bytes[0]&0x80 != 0 { + // We'll have to pad this with a 0x00 in order to + // stop it looking like a negative number. + to[0] = 0 + to = to[1:] + length++ + } + nBytes := copy(to, bytes) + to = to[nBytes:] + length += nBytes + } + + lengthBytes[0] = byte(length >> 24) + lengthBytes[1] = byte(length >> 16) + lengthBytes[2] = byte(length >> 8) + lengthBytes[3] = byte(length) + return to +} + +func writeInt(w io.Writer, n *big.Int) { + length := intLength(n) + buf := make([]byte, length) + marshalInt(buf, n) + w.Write(buf) +} + +func writeString(w io.Writer, s []byte) { + var lengthBytes [4]byte + lengthBytes[0] = byte(len(s) >> 24) + lengthBytes[1] = byte(len(s) >> 16) + lengthBytes[2] = byte(len(s) >> 8) + lengthBytes[3] = byte(len(s)) + w.Write(lengthBytes[:]) + w.Write(s) +} + +func stringLength(n int) int { + return 4 + n +} + +func marshalString(to []byte, s []byte) []byte { + to[0] = byte(len(s) >> 24) + to[1] = byte(len(s) >> 16) + to[2] = byte(len(s) >> 8) + to[3] = byte(len(s)) + to = to[4:] + copy(to, s) + return to[len(s):] +} + +var bigIntType = reflect.TypeOf((*big.Int)(nil)) + +// Decode a packet into its corresponding message. +func decode(packet []byte) (interface{}, error) { + var msg interface{} + switch packet[0] { + case msgDisconnect: + msg = new(disconnectMsg) + case msgServiceRequest: + msg = new(serviceRequestMsg) + case msgServiceAccept: + msg = new(serviceAcceptMsg) + case msgKexInit: + msg = new(kexInitMsg) + case msgKexDHInit: + msg = new(kexDHInitMsg) + case msgKexDHReply: + msg = new(kexDHReplyMsg) + case msgUserAuthRequest: + msg = new(userAuthRequestMsg) + case msgUserAuthSuccess: + return new(userAuthSuccessMsg), nil + case msgUserAuthFailure: + msg = new(userAuthFailureMsg) + case msgUserAuthPubKeyOk: + msg = new(userAuthPubKeyOkMsg) + case msgGlobalRequest: + msg = new(globalRequestMsg) + case msgRequestSuccess: + msg = new(globalRequestSuccessMsg) + case msgRequestFailure: + msg = new(globalRequestFailureMsg) + case msgChannelOpen: + msg = new(channelOpenMsg) + case msgChannelData: + msg = new(channelDataMsg) + case msgChannelOpenConfirm: + msg = new(channelOpenConfirmMsg) + case msgChannelOpenFailure: + msg = new(channelOpenFailureMsg) + case msgChannelWindowAdjust: + msg = new(windowAdjustMsg) + case msgChannelEOF: + msg = new(channelEOFMsg) + case msgChannelClose: + msg = new(channelCloseMsg) + case msgChannelRequest: + msg = new(channelRequestMsg) + case msgChannelSuccess: + msg = new(channelRequestSuccessMsg) + case msgChannelFailure: + msg = new(channelRequestFailureMsg) + default: + return nil, unexpectedMessageError(0, packet[0]) + } + if err := Unmarshal(packet, msg); err != nil { + return nil, err + } + return msg, nil +} + +var packetTypeNames = map[byte]string{ + msgDisconnect: "disconnectMsg", + msgServiceRequest: "serviceRequestMsg", + msgServiceAccept: "serviceAcceptMsg", + msgKexInit: "kexInitMsg", + msgKexDHInit: "kexDHInitMsg", + msgKexDHReply: "kexDHReplyMsg", + msgUserAuthRequest: "userAuthRequestMsg", + msgUserAuthSuccess: "userAuthSuccessMsg", + msgUserAuthFailure: "userAuthFailureMsg", + msgUserAuthPubKeyOk: "userAuthPubKeyOkMsg", + msgGlobalRequest: "globalRequestMsg", + msgRequestSuccess: "globalRequestSuccessMsg", + msgRequestFailure: "globalRequestFailureMsg", + msgChannelOpen: "channelOpenMsg", + msgChannelData: "channelDataMsg", + msgChannelOpenConfirm: "channelOpenConfirmMsg", + msgChannelOpenFailure: "channelOpenFailureMsg", + msgChannelWindowAdjust: "windowAdjustMsg", + msgChannelEOF: "channelEOFMsg", + msgChannelClose: "channelCloseMsg", + msgChannelRequest: "channelRequestMsg", + msgChannelSuccess: "channelRequestSuccessMsg", + msgChannelFailure: "channelRequestFailureMsg", +} diff --git a/vendor/golang.org/x/crypto/ssh/mux.go b/vendor/golang.org/x/crypto/ssh/mux.go new file mode 100644 index 00000000..f1901627 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/mux.go @@ -0,0 +1,330 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "encoding/binary" + "fmt" + "io" + "log" + "sync" + "sync/atomic" +) + +// debugMux, if set, causes messages in the connection protocol to be +// logged. +const debugMux = false + +// chanList is a thread safe channel list. +type chanList struct { + // protects concurrent access to chans + sync.Mutex + + // chans are indexed by the local id of the channel, which the + // other side should send in the PeersId field. + chans []*channel + + // This is a debugging aid: it offsets all IDs by this + // amount. This helps distinguish otherwise identical + // server/client muxes + offset uint32 +} + +// Assigns a channel ID to the given channel. +func (c *chanList) add(ch *channel) uint32 { + c.Lock() + defer c.Unlock() + for i := range c.chans { + if c.chans[i] == nil { + c.chans[i] = ch + return uint32(i) + c.offset + } + } + c.chans = append(c.chans, ch) + return uint32(len(c.chans)-1) + c.offset +} + +// getChan returns the channel for the given ID. +func (c *chanList) getChan(id uint32) *channel { + id -= c.offset + + c.Lock() + defer c.Unlock() + if id < uint32(len(c.chans)) { + return c.chans[id] + } + return nil +} + +func (c *chanList) remove(id uint32) { + id -= c.offset + c.Lock() + if id < uint32(len(c.chans)) { + c.chans[id] = nil + } + c.Unlock() +} + +// dropAll forgets all channels it knows, returning them in a slice. +func (c *chanList) dropAll() []*channel { + c.Lock() + defer c.Unlock() + var r []*channel + + for _, ch := range c.chans { + if ch == nil { + continue + } + r = append(r, ch) + } + c.chans = nil + return r +} + +// mux represents the state for the SSH connection protocol, which +// multiplexes many channels onto a single packet transport. +type mux struct { + conn packetConn + chanList chanList + + incomingChannels chan NewChannel + + globalSentMu sync.Mutex + globalResponses chan interface{} + incomingRequests chan *Request + + errCond *sync.Cond + err error +} + +// When debugging, each new chanList instantiation has a different +// offset. +var globalOff uint32 + +func (m *mux) Wait() error { + m.errCond.L.Lock() + defer m.errCond.L.Unlock() + for m.err == nil { + m.errCond.Wait() + } + return m.err +} + +// newMux returns a mux that runs over the given connection. +func newMux(p packetConn) *mux { + m := &mux{ + conn: p, + incomingChannels: make(chan NewChannel, chanSize), + globalResponses: make(chan interface{}, 1), + incomingRequests: make(chan *Request, chanSize), + errCond: newCond(), + } + if debugMux { + m.chanList.offset = atomic.AddUint32(&globalOff, 1) + } + + go m.loop() + return m +} + +func (m *mux) sendMessage(msg interface{}) error { + p := Marshal(msg) + if debugMux { + log.Printf("send global(%d): %#v", m.chanList.offset, msg) + } + return m.conn.writePacket(p) +} + +func (m *mux) SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) { + if wantReply { + m.globalSentMu.Lock() + defer m.globalSentMu.Unlock() + } + + if err := m.sendMessage(globalRequestMsg{ + Type: name, + WantReply: wantReply, + Data: payload, + }); err != nil { + return false, nil, err + } + + if !wantReply { + return false, nil, nil + } + + msg, ok := <-m.globalResponses + if !ok { + return false, nil, io.EOF + } + switch msg := msg.(type) { + case *globalRequestFailureMsg: + return false, msg.Data, nil + case *globalRequestSuccessMsg: + return true, msg.Data, nil + default: + return false, nil, fmt.Errorf("ssh: unexpected response to request: %#v", msg) + } +} + +// ackRequest must be called after processing a global request that +// has WantReply set. +func (m *mux) ackRequest(ok bool, data []byte) error { + if ok { + return m.sendMessage(globalRequestSuccessMsg{Data: data}) + } + return m.sendMessage(globalRequestFailureMsg{Data: data}) +} + +func (m *mux) Close() error { + return m.conn.Close() +} + +// loop runs the connection machine. It will process packets until an +// error is encountered. To synchronize on loop exit, use mux.Wait. +func (m *mux) loop() { + var err error + for err == nil { + err = m.onePacket() + } + + for _, ch := range m.chanList.dropAll() { + ch.close() + } + + close(m.incomingChannels) + close(m.incomingRequests) + close(m.globalResponses) + + m.conn.Close() + + m.errCond.L.Lock() + m.err = err + m.errCond.Broadcast() + m.errCond.L.Unlock() + + if debugMux { + log.Println("loop exit", err) + } +} + +// onePacket reads and processes one packet. +func (m *mux) onePacket() error { + packet, err := m.conn.readPacket() + if err != nil { + return err + } + + if debugMux { + if packet[0] == msgChannelData || packet[0] == msgChannelExtendedData { + log.Printf("decoding(%d): data packet - %d bytes", m.chanList.offset, len(packet)) + } else { + p, _ := decode(packet) + log.Printf("decoding(%d): %d %#v - %d bytes", m.chanList.offset, packet[0], p, len(packet)) + } + } + + switch packet[0] { + case msgChannelOpen: + return m.handleChannelOpen(packet) + case msgGlobalRequest, msgRequestSuccess, msgRequestFailure: + return m.handleGlobalPacket(packet) + } + + // assume a channel packet. + if len(packet) < 5 { + return parseError(packet[0]) + } + id := binary.BigEndian.Uint32(packet[1:]) + ch := m.chanList.getChan(id) + if ch == nil { + return fmt.Errorf("ssh: invalid channel %d", id) + } + + return ch.handlePacket(packet) +} + +func (m *mux) handleGlobalPacket(packet []byte) error { + msg, err := decode(packet) + if err != nil { + return err + } + + switch msg := msg.(type) { + case *globalRequestMsg: + m.incomingRequests <- &Request{ + Type: msg.Type, + WantReply: msg.WantReply, + Payload: msg.Data, + mux: m, + } + case *globalRequestSuccessMsg, *globalRequestFailureMsg: + m.globalResponses <- msg + default: + panic(fmt.Sprintf("not a global message %#v", msg)) + } + + return nil +} + +// handleChannelOpen schedules a channel to be Accept()ed. +func (m *mux) handleChannelOpen(packet []byte) error { + var msg channelOpenMsg + if err := Unmarshal(packet, &msg); err != nil { + return err + } + + if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 { + failMsg := channelOpenFailureMsg{ + PeersID: msg.PeersID, + Reason: ConnectionFailed, + Message: "invalid request", + Language: "en_US.UTF-8", + } + return m.sendMessage(failMsg) + } + + c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData) + c.remoteId = msg.PeersID + c.maxRemotePayload = msg.MaxPacketSize + c.remoteWin.add(msg.PeersWindow) + m.incomingChannels <- c + return nil +} + +func (m *mux) OpenChannel(chanType string, extra []byte) (Channel, <-chan *Request, error) { + ch, err := m.openChannel(chanType, extra) + if err != nil { + return nil, nil, err + } + + return ch, ch.incomingRequests, nil +} + +func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) { + ch := m.newChannel(chanType, channelOutbound, extra) + + ch.maxIncomingPayload = channelMaxPacket + + open := channelOpenMsg{ + ChanType: chanType, + PeersWindow: ch.myWindow, + MaxPacketSize: ch.maxIncomingPayload, + TypeSpecificData: extra, + PeersID: ch.localId, + } + if err := m.sendMessage(open); err != nil { + return nil, err + } + + switch msg := (<-ch.msg).(type) { + case *channelOpenConfirmMsg: + return ch, nil + case *channelOpenFailureMsg: + return nil, &OpenChannelError{msg.Reason, msg.Message} + default: + return nil, fmt.Errorf("ssh: unexpected packet in response to channel open: %T", msg) + } +} diff --git a/vendor/golang.org/x/crypto/ssh/server.go b/vendor/golang.org/x/crypto/ssh/server.go new file mode 100644 index 00000000..e86e8966 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/server.go @@ -0,0 +1,594 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bytes" + "errors" + "fmt" + "io" + "net" + "strings" +) + +// The Permissions type holds fine-grained permissions that are +// specific to a user or a specific authentication method for a user. +// The Permissions value for a successful authentication attempt is +// available in ServerConn, so it can be used to pass information from +// the user-authentication phase to the application layer. +type Permissions struct { + // CriticalOptions indicate restrictions to the default + // permissions, and are typically used in conjunction with + // user certificates. The standard for SSH certificates + // defines "force-command" (only allow the given command to + // execute) and "source-address" (only allow connections from + // the given address). The SSH package currently only enforces + // the "source-address" critical option. It is up to server + // implementations to enforce other critical options, such as + // "force-command", by checking them after the SSH handshake + // is successful. In general, SSH servers should reject + // connections that specify critical options that are unknown + // or not supported. + CriticalOptions map[string]string + + // Extensions are extra functionality that the server may + // offer on authenticated connections. Lack of support for an + // extension does not preclude authenticating a user. Common + // extensions are "permit-agent-forwarding", + // "permit-X11-forwarding". The Go SSH library currently does + // not act on any extension, and it is up to server + // implementations to honor them. Extensions can be used to + // pass data from the authentication callbacks to the server + // application layer. + Extensions map[string]string +} + +// ServerConfig holds server specific configuration data. +type ServerConfig struct { + // Config contains configuration shared between client and server. + Config + + hostKeys []Signer + + // NoClientAuth is true if clients are allowed to connect without + // authenticating. + NoClientAuth bool + + // MaxAuthTries specifies the maximum number of authentication attempts + // permitted per connection. If set to a negative number, the number of + // attempts are unlimited. If set to zero, the number of attempts are limited + // to 6. + MaxAuthTries int + + // PasswordCallback, if non-nil, is called when a user + // attempts to authenticate using a password. + PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error) + + // PublicKeyCallback, if non-nil, is called when a client + // offers a public key for authentication. It must return a nil error + // if the given public key can be used to authenticate the + // given user. For example, see CertChecker.Authenticate. A + // call to this function does not guarantee that the key + // offered is in fact used to authenticate. To record any data + // depending on the public key, store it inside a + // Permissions.Extensions entry. + PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error) + + // KeyboardInteractiveCallback, if non-nil, is called when + // keyboard-interactive authentication is selected (RFC + // 4256). The client object's Challenge function should be + // used to query the user. The callback may offer multiple + // Challenge rounds. To avoid information leaks, the client + // should be presented a challenge even if the user is + // unknown. + KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error) + + // AuthLogCallback, if non-nil, is called to log all authentication + // attempts. + AuthLogCallback func(conn ConnMetadata, method string, err error) + + // ServerVersion is the version identification string to announce in + // the public handshake. + // If empty, a reasonable default is used. + // Note that RFC 4253 section 4.2 requires that this string start with + // "SSH-2.0-". + ServerVersion string + + // BannerCallback, if present, is called and the return string is sent to + // the client after key exchange completed but before authentication. + BannerCallback func(conn ConnMetadata) string +} + +// AddHostKey adds a private key as a host key. If an existing host +// key exists with the same algorithm, it is overwritten. Each server +// config must have at least one host key. +func (s *ServerConfig) AddHostKey(key Signer) { + for i, k := range s.hostKeys { + if k.PublicKey().Type() == key.PublicKey().Type() { + s.hostKeys[i] = key + return + } + } + + s.hostKeys = append(s.hostKeys, key) +} + +// cachedPubKey contains the results of querying whether a public key is +// acceptable for a user. +type cachedPubKey struct { + user string + pubKeyData []byte + result error + perms *Permissions +} + +const maxCachedPubKeys = 16 + +// pubKeyCache caches tests for public keys. Since SSH clients +// will query whether a public key is acceptable before attempting to +// authenticate with it, we end up with duplicate queries for public +// key validity. The cache only applies to a single ServerConn. +type pubKeyCache struct { + keys []cachedPubKey +} + +// get returns the result for a given user/algo/key tuple. +func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) { + for _, k := range c.keys { + if k.user == user && bytes.Equal(k.pubKeyData, pubKeyData) { + return k, true + } + } + return cachedPubKey{}, false +} + +// add adds the given tuple to the cache. +func (c *pubKeyCache) add(candidate cachedPubKey) { + if len(c.keys) < maxCachedPubKeys { + c.keys = append(c.keys, candidate) + } +} + +// ServerConn is an authenticated SSH connection, as seen from the +// server +type ServerConn struct { + Conn + + // If the succeeding authentication callback returned a + // non-nil Permissions pointer, it is stored here. + Permissions *Permissions +} + +// NewServerConn starts a new SSH server with c as the underlying +// transport. It starts with a handshake and, if the handshake is +// unsuccessful, it closes the connection and returns an error. The +// Request and NewChannel channels must be serviced, or the connection +// will hang. +// +// The returned error may be of type *ServerAuthError for +// authentication errors. +func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) { + fullConf := *config + fullConf.SetDefaults() + if fullConf.MaxAuthTries == 0 { + fullConf.MaxAuthTries = 6 + } + + s := &connection{ + sshConn: sshConn{conn: c}, + } + perms, err := s.serverHandshake(&fullConf) + if err != nil { + c.Close() + return nil, nil, nil, err + } + return &ServerConn{s, perms}, s.mux.incomingChannels, s.mux.incomingRequests, nil +} + +// signAndMarshal signs the data with the appropriate algorithm, +// and serializes the result in SSH wire format. +func signAndMarshal(k Signer, rand io.Reader, data []byte) ([]byte, error) { + sig, err := k.Sign(rand, data) + if err != nil { + return nil, err + } + + return Marshal(sig), nil +} + +// handshake performs key exchange and user authentication. +func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) { + if len(config.hostKeys) == 0 { + return nil, errors.New("ssh: server has no host keys") + } + + if !config.NoClientAuth && config.PasswordCallback == nil && config.PublicKeyCallback == nil && config.KeyboardInteractiveCallback == nil { + return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false") + } + + if config.ServerVersion != "" { + s.serverVersion = []byte(config.ServerVersion) + } else { + s.serverVersion = []byte(packageVersion) + } + var err error + s.clientVersion, err = exchangeVersions(s.sshConn.conn, s.serverVersion) + if err != nil { + return nil, err + } + + tr := newTransport(s.sshConn.conn, config.Rand, false /* not client */) + s.transport = newServerTransport(tr, s.clientVersion, s.serverVersion, config) + + if err := s.transport.waitSession(); err != nil { + return nil, err + } + + // We just did the key change, so the session ID is established. + s.sessionID = s.transport.getSessionID() + + var packet []byte + if packet, err = s.transport.readPacket(); err != nil { + return nil, err + } + + var serviceRequest serviceRequestMsg + if err = Unmarshal(packet, &serviceRequest); err != nil { + return nil, err + } + if serviceRequest.Service != serviceUserAuth { + return nil, errors.New("ssh: requested service '" + serviceRequest.Service + "' before authenticating") + } + serviceAccept := serviceAcceptMsg{ + Service: serviceUserAuth, + } + if err := s.transport.writePacket(Marshal(&serviceAccept)); err != nil { + return nil, err + } + + perms, err := s.serverAuthenticate(config) + if err != nil { + return nil, err + } + s.mux = newMux(s.transport) + return perms, err +} + +func isAcceptableAlgo(algo string) bool { + switch algo { + case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoED25519, + CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01: + return true + } + return false +} + +func checkSourceAddress(addr net.Addr, sourceAddrs string) error { + if addr == nil { + return errors.New("ssh: no address known for client, but source-address match required") + } + + tcpAddr, ok := addr.(*net.TCPAddr) + if !ok { + return fmt.Errorf("ssh: remote address %v is not an TCP address when checking source-address match", addr) + } + + for _, sourceAddr := range strings.Split(sourceAddrs, ",") { + if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil { + if allowedIP.Equal(tcpAddr.IP) { + return nil + } + } else { + _, ipNet, err := net.ParseCIDR(sourceAddr) + if err != nil { + return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err) + } + + if ipNet.Contains(tcpAddr.IP) { + return nil + } + } + } + + return fmt.Errorf("ssh: remote address %v is not allowed because of source-address restriction", addr) +} + +// ServerAuthError represents server authentication errors and is +// sometimes returned by NewServerConn. It appends any authentication +// errors that may occur, and is returned if all of the authentication +// methods provided by the user failed to authenticate. +type ServerAuthError struct { + // Errors contains authentication errors returned by the authentication + // callback methods. The first entry is typically ErrNoAuth. + Errors []error +} + +func (l ServerAuthError) Error() string { + var errs []string + for _, err := range l.Errors { + errs = append(errs, err.Error()) + } + return "[" + strings.Join(errs, ", ") + "]" +} + +// ErrNoAuth is the error value returned if no +// authentication method has been passed yet. This happens as a normal +// part of the authentication loop, since the client first tries +// 'none' authentication to discover available methods. +// It is returned in ServerAuthError.Errors from NewServerConn. +var ErrNoAuth = errors.New("ssh: no auth passed yet") + +func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) { + sessionID := s.transport.getSessionID() + var cache pubKeyCache + var perms *Permissions + + authFailures := 0 + var authErrs []error + var displayedBanner bool + +userAuthLoop: + for { + if authFailures >= config.MaxAuthTries && config.MaxAuthTries > 0 { + discMsg := &disconnectMsg{ + Reason: 2, + Message: "too many authentication failures", + } + + if err := s.transport.writePacket(Marshal(discMsg)); err != nil { + return nil, err + } + + return nil, discMsg + } + + var userAuthReq userAuthRequestMsg + if packet, err := s.transport.readPacket(); err != nil { + if err == io.EOF { + return nil, &ServerAuthError{Errors: authErrs} + } + return nil, err + } else if err = Unmarshal(packet, &userAuthReq); err != nil { + return nil, err + } + + if userAuthReq.Service != serviceSSH { + return nil, errors.New("ssh: client attempted to negotiate for unknown service: " + userAuthReq.Service) + } + + s.user = userAuthReq.User + + if !displayedBanner && config.BannerCallback != nil { + displayedBanner = true + msg := config.BannerCallback(s) + if msg != "" { + bannerMsg := &userAuthBannerMsg{ + Message: msg, + } + if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil { + return nil, err + } + } + } + + perms = nil + authErr := ErrNoAuth + + switch userAuthReq.Method { + case "none": + if config.NoClientAuth { + authErr = nil + } + + // allow initial attempt of 'none' without penalty + if authFailures == 0 { + authFailures-- + } + case "password": + if config.PasswordCallback == nil { + authErr = errors.New("ssh: password auth not configured") + break + } + payload := userAuthReq.Payload + if len(payload) < 1 || payload[0] != 0 { + return nil, parseError(msgUserAuthRequest) + } + payload = payload[1:] + password, payload, ok := parseString(payload) + if !ok || len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + + perms, authErr = config.PasswordCallback(s, password) + case "keyboard-interactive": + if config.KeyboardInteractiveCallback == nil { + authErr = errors.New("ssh: keyboard-interactive auth not configured") + break + } + + prompter := &sshClientKeyboardInteractive{s} + perms, authErr = config.KeyboardInteractiveCallback(s, prompter.Challenge) + case "publickey": + if config.PublicKeyCallback == nil { + authErr = errors.New("ssh: publickey auth not configured") + break + } + payload := userAuthReq.Payload + if len(payload) < 1 { + return nil, parseError(msgUserAuthRequest) + } + isQuery := payload[0] == 0 + payload = payload[1:] + algoBytes, payload, ok := parseString(payload) + if !ok { + return nil, parseError(msgUserAuthRequest) + } + algo := string(algoBytes) + if !isAcceptableAlgo(algo) { + authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo) + break + } + + pubKeyData, payload, ok := parseString(payload) + if !ok { + return nil, parseError(msgUserAuthRequest) + } + + pubKey, err := ParsePublicKey(pubKeyData) + if err != nil { + return nil, err + } + + candidate, ok := cache.get(s.user, pubKeyData) + if !ok { + candidate.user = s.user + candidate.pubKeyData = pubKeyData + candidate.perms, candidate.result = config.PublicKeyCallback(s, pubKey) + if candidate.result == nil && candidate.perms != nil && candidate.perms.CriticalOptions != nil && candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" { + candidate.result = checkSourceAddress( + s.RemoteAddr(), + candidate.perms.CriticalOptions[sourceAddressCriticalOption]) + } + cache.add(candidate) + } + + if isQuery { + // The client can query if the given public key + // would be okay. + + if len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + + if candidate.result == nil { + okMsg := userAuthPubKeyOkMsg{ + Algo: algo, + PubKey: pubKeyData, + } + if err = s.transport.writePacket(Marshal(&okMsg)); err != nil { + return nil, err + } + continue userAuthLoop + } + authErr = candidate.result + } else { + sig, payload, ok := parseSignature(payload) + if !ok || len(payload) > 0 { + return nil, parseError(msgUserAuthRequest) + } + // Ensure the public key algo and signature algo + // are supported. Compare the private key + // algorithm name that corresponds to algo with + // sig.Format. This is usually the same, but + // for certs, the names differ. + if !isAcceptableAlgo(sig.Format) { + authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format) + break + } + signedData := buildDataSignedForAuth(sessionID, userAuthReq, algoBytes, pubKeyData) + + if err := pubKey.Verify(signedData, sig); err != nil { + return nil, err + } + + authErr = candidate.result + perms = candidate.perms + } + default: + authErr = fmt.Errorf("ssh: unknown method %q", userAuthReq.Method) + } + + authErrs = append(authErrs, authErr) + + if config.AuthLogCallback != nil { + config.AuthLogCallback(s, userAuthReq.Method, authErr) + } + + if authErr == nil { + break userAuthLoop + } + + authFailures++ + + var failureMsg userAuthFailureMsg + if config.PasswordCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "password") + } + if config.PublicKeyCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "publickey") + } + if config.KeyboardInteractiveCallback != nil { + failureMsg.Methods = append(failureMsg.Methods, "keyboard-interactive") + } + + if len(failureMsg.Methods) == 0 { + return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false") + } + + if err := s.transport.writePacket(Marshal(&failureMsg)); err != nil { + return nil, err + } + } + + if err := s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil { + return nil, err + } + return perms, nil +} + +// sshClientKeyboardInteractive implements a ClientKeyboardInteractive by +// asking the client on the other side of a ServerConn. +type sshClientKeyboardInteractive struct { + *connection +} + +func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, questions []string, echos []bool) (answers []string, err error) { + if len(questions) != len(echos) { + return nil, errors.New("ssh: echos and questions must have equal length") + } + + var prompts []byte + for i := range questions { + prompts = appendString(prompts, questions[i]) + prompts = appendBool(prompts, echos[i]) + } + + if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{ + Instruction: instruction, + NumPrompts: uint32(len(questions)), + Prompts: prompts, + })); err != nil { + return nil, err + } + + packet, err := c.transport.readPacket() + if err != nil { + return nil, err + } + if packet[0] != msgUserAuthInfoResponse { + return nil, unexpectedMessageError(msgUserAuthInfoResponse, packet[0]) + } + packet = packet[1:] + + n, packet, ok := parseUint32(packet) + if !ok || int(n) != len(questions) { + return nil, parseError(msgUserAuthInfoResponse) + } + + for i := uint32(0); i < n; i++ { + ans, rest, ok := parseString(packet) + if !ok { + return nil, parseError(msgUserAuthInfoResponse) + } + + answers = append(answers, string(ans)) + packet = rest + } + if len(packet) != 0 { + return nil, errors.New("ssh: junk at end of message") + } + + return answers, nil +} diff --git a/vendor/golang.org/x/crypto/ssh/session.go b/vendor/golang.org/x/crypto/ssh/session.go new file mode 100644 index 00000000..d3321f6b --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/session.go @@ -0,0 +1,647 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +// Session implements an interactive session described in +// "RFC 4254, section 6". + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" + "io/ioutil" + "sync" +) + +type Signal string + +// POSIX signals as listed in RFC 4254 Section 6.10. +const ( + SIGABRT Signal = "ABRT" + SIGALRM Signal = "ALRM" + SIGFPE Signal = "FPE" + SIGHUP Signal = "HUP" + SIGILL Signal = "ILL" + SIGINT Signal = "INT" + SIGKILL Signal = "KILL" + SIGPIPE Signal = "PIPE" + SIGQUIT Signal = "QUIT" + SIGSEGV Signal = "SEGV" + SIGTERM Signal = "TERM" + SIGUSR1 Signal = "USR1" + SIGUSR2 Signal = "USR2" +) + +var signals = map[Signal]int{ + SIGABRT: 6, + SIGALRM: 14, + SIGFPE: 8, + SIGHUP: 1, + SIGILL: 4, + SIGINT: 2, + SIGKILL: 9, + SIGPIPE: 13, + SIGQUIT: 3, + SIGSEGV: 11, + SIGTERM: 15, +} + +type TerminalModes map[uint8]uint32 + +// POSIX terminal mode flags as listed in RFC 4254 Section 8. +const ( + tty_OP_END = 0 + VINTR = 1 + VQUIT = 2 + VERASE = 3 + VKILL = 4 + VEOF = 5 + VEOL = 6 + VEOL2 = 7 + VSTART = 8 + VSTOP = 9 + VSUSP = 10 + VDSUSP = 11 + VREPRINT = 12 + VWERASE = 13 + VLNEXT = 14 + VFLUSH = 15 + VSWTCH = 16 + VSTATUS = 17 + VDISCARD = 18 + IGNPAR = 30 + PARMRK = 31 + INPCK = 32 + ISTRIP = 33 + INLCR = 34 + IGNCR = 35 + ICRNL = 36 + IUCLC = 37 + IXON = 38 + IXANY = 39 + IXOFF = 40 + IMAXBEL = 41 + ISIG = 50 + ICANON = 51 + XCASE = 52 + ECHO = 53 + ECHOE = 54 + ECHOK = 55 + ECHONL = 56 + NOFLSH = 57 + TOSTOP = 58 + IEXTEN = 59 + ECHOCTL = 60 + ECHOKE = 61 + PENDIN = 62 + OPOST = 70 + OLCUC = 71 + ONLCR = 72 + OCRNL = 73 + ONOCR = 74 + ONLRET = 75 + CS7 = 90 + CS8 = 91 + PARENB = 92 + PARODD = 93 + TTY_OP_ISPEED = 128 + TTY_OP_OSPEED = 129 +) + +// A Session represents a connection to a remote command or shell. +type Session struct { + // Stdin specifies the remote process's standard input. + // If Stdin is nil, the remote process reads from an empty + // bytes.Buffer. + Stdin io.Reader + + // Stdout and Stderr specify the remote process's standard + // output and error. + // + // If either is nil, Run connects the corresponding file + // descriptor to an instance of ioutil.Discard. There is a + // fixed amount of buffering that is shared for the two streams. + // If either blocks it may eventually cause the remote + // command to block. + Stdout io.Writer + Stderr io.Writer + + ch Channel // the channel backing this session + started bool // true once Start, Run or Shell is invoked. + copyFuncs []func() error + errors chan error // one send per copyFunc + + // true if pipe method is active + stdinpipe, stdoutpipe, stderrpipe bool + + // stdinPipeWriter is non-nil if StdinPipe has not been called + // and Stdin was specified by the user; it is the write end of + // a pipe connecting Session.Stdin to the stdin channel. + stdinPipeWriter io.WriteCloser + + exitStatus chan error +} + +// SendRequest sends an out-of-band channel request on the SSH channel +// underlying the session. +func (s *Session) SendRequest(name string, wantReply bool, payload []byte) (bool, error) { + return s.ch.SendRequest(name, wantReply, payload) +} + +func (s *Session) Close() error { + return s.ch.Close() +} + +// RFC 4254 Section 6.4. +type setenvRequest struct { + Name string + Value string +} + +// Setenv sets an environment variable that will be applied to any +// command executed by Shell or Run. +func (s *Session) Setenv(name, value string) error { + msg := setenvRequest{ + Name: name, + Value: value, + } + ok, err := s.ch.SendRequest("env", true, Marshal(&msg)) + if err == nil && !ok { + err = errors.New("ssh: setenv failed") + } + return err +} + +// RFC 4254 Section 6.2. +type ptyRequestMsg struct { + Term string + Columns uint32 + Rows uint32 + Width uint32 + Height uint32 + Modelist string +} + +// RequestPty requests the association of a pty with the session on the remote host. +func (s *Session) RequestPty(term string, h, w int, termmodes TerminalModes) error { + var tm []byte + for k, v := range termmodes { + kv := struct { + Key byte + Val uint32 + }{k, v} + + tm = append(tm, Marshal(&kv)...) + } + tm = append(tm, tty_OP_END) + req := ptyRequestMsg{ + Term: term, + Columns: uint32(w), + Rows: uint32(h), + Width: uint32(w * 8), + Height: uint32(h * 8), + Modelist: string(tm), + } + ok, err := s.ch.SendRequest("pty-req", true, Marshal(&req)) + if err == nil && !ok { + err = errors.New("ssh: pty-req failed") + } + return err +} + +// RFC 4254 Section 6.5. +type subsystemRequestMsg struct { + Subsystem string +} + +// RequestSubsystem requests the association of a subsystem with the session on the remote host. +// A subsystem is a predefined command that runs in the background when the ssh session is initiated +func (s *Session) RequestSubsystem(subsystem string) error { + msg := subsystemRequestMsg{ + Subsystem: subsystem, + } + ok, err := s.ch.SendRequest("subsystem", true, Marshal(&msg)) + if err == nil && !ok { + err = errors.New("ssh: subsystem request failed") + } + return err +} + +// RFC 4254 Section 6.7. +type ptyWindowChangeMsg struct { + Columns uint32 + Rows uint32 + Width uint32 + Height uint32 +} + +// WindowChange informs the remote host about a terminal window dimension change to h rows and w columns. +func (s *Session) WindowChange(h, w int) error { + req := ptyWindowChangeMsg{ + Columns: uint32(w), + Rows: uint32(h), + Width: uint32(w * 8), + Height: uint32(h * 8), + } + _, err := s.ch.SendRequest("window-change", false, Marshal(&req)) + return err +} + +// RFC 4254 Section 6.9. +type signalMsg struct { + Signal string +} + +// Signal sends the given signal to the remote process. +// sig is one of the SIG* constants. +func (s *Session) Signal(sig Signal) error { + msg := signalMsg{ + Signal: string(sig), + } + + _, err := s.ch.SendRequest("signal", false, Marshal(&msg)) + return err +} + +// RFC 4254 Section 6.5. +type execMsg struct { + Command string +} + +// Start runs cmd on the remote host. Typically, the remote +// server passes cmd to the shell for interpretation. +// A Session only accepts one call to Run, Start or Shell. +func (s *Session) Start(cmd string) error { + if s.started { + return errors.New("ssh: session already started") + } + req := execMsg{ + Command: cmd, + } + + ok, err := s.ch.SendRequest("exec", true, Marshal(&req)) + if err == nil && !ok { + err = fmt.Errorf("ssh: command %v failed", cmd) + } + if err != nil { + return err + } + return s.start() +} + +// Run runs cmd on the remote host. Typically, the remote +// server passes cmd to the shell for interpretation. +// A Session only accepts one call to Run, Start, Shell, Output, +// or CombinedOutput. +// +// The returned error is nil if the command runs, has no problems +// copying stdin, stdout, and stderr, and exits with a zero exit +// status. +// +// If the remote server does not send an exit status, an error of type +// *ExitMissingError is returned. If the command completes +// unsuccessfully or is interrupted by a signal, the error is of type +// *ExitError. Other error types may be returned for I/O problems. +func (s *Session) Run(cmd string) error { + err := s.Start(cmd) + if err != nil { + return err + } + return s.Wait() +} + +// Output runs cmd on the remote host and returns its standard output. +func (s *Session) Output(cmd string) ([]byte, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + var b bytes.Buffer + s.Stdout = &b + err := s.Run(cmd) + return b.Bytes(), err +} + +type singleWriter struct { + b bytes.Buffer + mu sync.Mutex +} + +func (w *singleWriter) Write(p []byte) (int, error) { + w.mu.Lock() + defer w.mu.Unlock() + return w.b.Write(p) +} + +// CombinedOutput runs cmd on the remote host and returns its combined +// standard output and standard error. +func (s *Session) CombinedOutput(cmd string) ([]byte, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + if s.Stderr != nil { + return nil, errors.New("ssh: Stderr already set") + } + var b singleWriter + s.Stdout = &b + s.Stderr = &b + err := s.Run(cmd) + return b.b.Bytes(), err +} + +// Shell starts a login shell on the remote host. A Session only +// accepts one call to Run, Start, Shell, Output, or CombinedOutput. +func (s *Session) Shell() error { + if s.started { + return errors.New("ssh: session already started") + } + + ok, err := s.ch.SendRequest("shell", true, nil) + if err == nil && !ok { + return errors.New("ssh: could not start shell") + } + if err != nil { + return err + } + return s.start() +} + +func (s *Session) start() error { + s.started = true + + type F func(*Session) + for _, setupFd := range []F{(*Session).stdin, (*Session).stdout, (*Session).stderr} { + setupFd(s) + } + + s.errors = make(chan error, len(s.copyFuncs)) + for _, fn := range s.copyFuncs { + go func(fn func() error) { + s.errors <- fn() + }(fn) + } + return nil +} + +// Wait waits for the remote command to exit. +// +// The returned error is nil if the command runs, has no problems +// copying stdin, stdout, and stderr, and exits with a zero exit +// status. +// +// If the remote server does not send an exit status, an error of type +// *ExitMissingError is returned. If the command completes +// unsuccessfully or is interrupted by a signal, the error is of type +// *ExitError. Other error types may be returned for I/O problems. +func (s *Session) Wait() error { + if !s.started { + return errors.New("ssh: session not started") + } + waitErr := <-s.exitStatus + + if s.stdinPipeWriter != nil { + s.stdinPipeWriter.Close() + } + var copyError error + for range s.copyFuncs { + if err := <-s.errors; err != nil && copyError == nil { + copyError = err + } + } + if waitErr != nil { + return waitErr + } + return copyError +} + +func (s *Session) wait(reqs <-chan *Request) error { + wm := Waitmsg{status: -1} + // Wait for msg channel to be closed before returning. + for msg := range reqs { + switch msg.Type { + case "exit-status": + wm.status = int(binary.BigEndian.Uint32(msg.Payload)) + case "exit-signal": + var sigval struct { + Signal string + CoreDumped bool + Error string + Lang string + } + if err := Unmarshal(msg.Payload, &sigval); err != nil { + return err + } + + // Must sanitize strings? + wm.signal = sigval.Signal + wm.msg = sigval.Error + wm.lang = sigval.Lang + default: + // This handles keepalives and matches + // OpenSSH's behaviour. + if msg.WantReply { + msg.Reply(false, nil) + } + } + } + if wm.status == 0 { + return nil + } + if wm.status == -1 { + // exit-status was never sent from server + if wm.signal == "" { + // signal was not sent either. RFC 4254 + // section 6.10 recommends against this + // behavior, but it is allowed, so we let + // clients handle it. + return &ExitMissingError{} + } + wm.status = 128 + if _, ok := signals[Signal(wm.signal)]; ok { + wm.status += signals[Signal(wm.signal)] + } + } + + return &ExitError{wm} +} + +// ExitMissingError is returned if a session is torn down cleanly, but +// the server sends no confirmation of the exit status. +type ExitMissingError struct{} + +func (e *ExitMissingError) Error() string { + return "wait: remote command exited without exit status or exit signal" +} + +func (s *Session) stdin() { + if s.stdinpipe { + return + } + var stdin io.Reader + if s.Stdin == nil { + stdin = new(bytes.Buffer) + } else { + r, w := io.Pipe() + go func() { + _, err := io.Copy(w, s.Stdin) + w.CloseWithError(err) + }() + stdin, s.stdinPipeWriter = r, w + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.ch, stdin) + if err1 := s.ch.CloseWrite(); err == nil && err1 != io.EOF { + err = err1 + } + return err + }) +} + +func (s *Session) stdout() { + if s.stdoutpipe { + return + } + if s.Stdout == nil { + s.Stdout = ioutil.Discard + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.Stdout, s.ch) + return err + }) +} + +func (s *Session) stderr() { + if s.stderrpipe { + return + } + if s.Stderr == nil { + s.Stderr = ioutil.Discard + } + s.copyFuncs = append(s.copyFuncs, func() error { + _, err := io.Copy(s.Stderr, s.ch.Stderr()) + return err + }) +} + +// sessionStdin reroutes Close to CloseWrite. +type sessionStdin struct { + io.Writer + ch Channel +} + +func (s *sessionStdin) Close() error { + return s.ch.CloseWrite() +} + +// StdinPipe returns a pipe that will be connected to the +// remote command's standard input when the command starts. +func (s *Session) StdinPipe() (io.WriteCloser, error) { + if s.Stdin != nil { + return nil, errors.New("ssh: Stdin already set") + } + if s.started { + return nil, errors.New("ssh: StdinPipe after process started") + } + s.stdinpipe = true + return &sessionStdin{s.ch, s.ch}, nil +} + +// StdoutPipe returns a pipe that will be connected to the +// remote command's standard output when the command starts. +// There is a fixed amount of buffering that is shared between +// stdout and stderr streams. If the StdoutPipe reader is +// not serviced fast enough it may eventually cause the +// remote command to block. +func (s *Session) StdoutPipe() (io.Reader, error) { + if s.Stdout != nil { + return nil, errors.New("ssh: Stdout already set") + } + if s.started { + return nil, errors.New("ssh: StdoutPipe after process started") + } + s.stdoutpipe = true + return s.ch, nil +} + +// StderrPipe returns a pipe that will be connected to the +// remote command's standard error when the command starts. +// There is a fixed amount of buffering that is shared between +// stdout and stderr streams. If the StderrPipe reader is +// not serviced fast enough it may eventually cause the +// remote command to block. +func (s *Session) StderrPipe() (io.Reader, error) { + if s.Stderr != nil { + return nil, errors.New("ssh: Stderr already set") + } + if s.started { + return nil, errors.New("ssh: StderrPipe after process started") + } + s.stderrpipe = true + return s.ch.Stderr(), nil +} + +// newSession returns a new interactive session on the remote host. +func newSession(ch Channel, reqs <-chan *Request) (*Session, error) { + s := &Session{ + ch: ch, + } + s.exitStatus = make(chan error, 1) + go func() { + s.exitStatus <- s.wait(reqs) + }() + + return s, nil +} + +// An ExitError reports unsuccessful completion of a remote command. +type ExitError struct { + Waitmsg +} + +func (e *ExitError) Error() string { + return e.Waitmsg.String() +} + +// Waitmsg stores the information about an exited remote command +// as reported by Wait. +type Waitmsg struct { + status int + signal string + msg string + lang string +} + +// ExitStatus returns the exit status of the remote command. +func (w Waitmsg) ExitStatus() int { + return w.status +} + +// Signal returns the exit signal of the remote command if +// it was terminated violently. +func (w Waitmsg) Signal() string { + return w.signal +} + +// Msg returns the exit message given by the remote command +func (w Waitmsg) Msg() string { + return w.msg +} + +// Lang returns the language tag. See RFC 3066 +func (w Waitmsg) Lang() string { + return w.lang +} + +func (w Waitmsg) String() string { + str := fmt.Sprintf("Process exited with status %v", w.status) + if w.signal != "" { + str += fmt.Sprintf(" from signal %v", w.signal) + } + if w.msg != "" { + str += fmt.Sprintf(". Reason was: %v", w.msg) + } + return str +} diff --git a/vendor/golang.org/x/crypto/ssh/streamlocal.go b/vendor/golang.org/x/crypto/ssh/streamlocal.go new file mode 100644 index 00000000..b171b330 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/streamlocal.go @@ -0,0 +1,116 @@ +package ssh + +import ( + "errors" + "io" + "net" +) + +// streamLocalChannelOpenDirectMsg is a struct used for SSH_MSG_CHANNEL_OPEN message +// with "direct-streamlocal@openssh.com" string. +// +// See openssh-portable/PROTOCOL, section 2.4. connection: Unix domain socket forwarding +// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL#L235 +type streamLocalChannelOpenDirectMsg struct { + socketPath string + reserved0 string + reserved1 uint32 +} + +// forwardedStreamLocalPayload is a struct used for SSH_MSG_CHANNEL_OPEN message +// with "forwarded-streamlocal@openssh.com" string. +type forwardedStreamLocalPayload struct { + SocketPath string + Reserved0 string +} + +// streamLocalChannelForwardMsg is a struct used for SSH2_MSG_GLOBAL_REQUEST message +// with "streamlocal-forward@openssh.com"/"cancel-streamlocal-forward@openssh.com" string. +type streamLocalChannelForwardMsg struct { + socketPath string +} + +// ListenUnix is similar to ListenTCP but uses a Unix domain socket. +func (c *Client) ListenUnix(socketPath string) (net.Listener, error) { + c.handleForwardsOnce.Do(c.handleForwards) + m := streamLocalChannelForwardMsg{ + socketPath, + } + // send message + ok, _, err := c.SendRequest("streamlocal-forward@openssh.com", true, Marshal(&m)) + if err != nil { + return nil, err + } + if !ok { + return nil, errors.New("ssh: streamlocal-forward@openssh.com request denied by peer") + } + ch := c.forwards.add(&net.UnixAddr{Name: socketPath, Net: "unix"}) + + return &unixListener{socketPath, c, ch}, nil +} + +func (c *Client) dialStreamLocal(socketPath string) (Channel, error) { + msg := streamLocalChannelOpenDirectMsg{ + socketPath: socketPath, + } + ch, in, err := c.OpenChannel("direct-streamlocal@openssh.com", Marshal(&msg)) + if err != nil { + return nil, err + } + go DiscardRequests(in) + return ch, err +} + +type unixListener struct { + socketPath string + + conn *Client + in <-chan forward +} + +// Accept waits for and returns the next connection to the listener. +func (l *unixListener) Accept() (net.Conn, error) { + s, ok := <-l.in + if !ok { + return nil, io.EOF + } + ch, incoming, err := s.newCh.Accept() + if err != nil { + return nil, err + } + go DiscardRequests(incoming) + + return &chanConn{ + Channel: ch, + laddr: &net.UnixAddr{ + Name: l.socketPath, + Net: "unix", + }, + raddr: &net.UnixAddr{ + Name: "@", + Net: "unix", + }, + }, nil +} + +// Close closes the listener. +func (l *unixListener) Close() error { + // this also closes the listener. + l.conn.forwards.remove(&net.UnixAddr{Name: l.socketPath, Net: "unix"}) + m := streamLocalChannelForwardMsg{ + l.socketPath, + } + ok, _, err := l.conn.SendRequest("cancel-streamlocal-forward@openssh.com", true, Marshal(&m)) + if err == nil && !ok { + err = errors.New("ssh: cancel-streamlocal-forward@openssh.com failed") + } + return err +} + +// Addr returns the listener's network address. +func (l *unixListener) Addr() net.Addr { + return &net.UnixAddr{ + Name: l.socketPath, + Net: "unix", + } +} diff --git a/vendor/golang.org/x/crypto/ssh/tcpip.go b/vendor/golang.org/x/crypto/ssh/tcpip.go new file mode 100644 index 00000000..80d35f5e --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/tcpip.go @@ -0,0 +1,474 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "errors" + "fmt" + "io" + "math/rand" + "net" + "strconv" + "strings" + "sync" + "time" +) + +// Listen requests the remote peer open a listening socket on +// addr. Incoming connections will be available by calling Accept on +// the returned net.Listener. The listener must be serviced, or the +// SSH connection may hang. +// N must be "tcp", "tcp4", "tcp6", or "unix". +func (c *Client) Listen(n, addr string) (net.Listener, error) { + switch n { + case "tcp", "tcp4", "tcp6": + laddr, err := net.ResolveTCPAddr(n, addr) + if err != nil { + return nil, err + } + return c.ListenTCP(laddr) + case "unix": + return c.ListenUnix(addr) + default: + return nil, fmt.Errorf("ssh: unsupported protocol: %s", n) + } +} + +// Automatic port allocation is broken with OpenSSH before 6.0. See +// also https://bugzilla.mindrot.org/show_bug.cgi?id=2017. In +// particular, OpenSSH 5.9 sends a channelOpenMsg with port number 0, +// rather than the actual port number. This means you can never open +// two different listeners with auto allocated ports. We work around +// this by trying explicit ports until we succeed. + +const openSSHPrefix = "OpenSSH_" + +var portRandomizer = rand.New(rand.NewSource(time.Now().UnixNano())) + +// isBrokenOpenSSHVersion returns true if the given version string +// specifies a version of OpenSSH that is known to have a bug in port +// forwarding. +func isBrokenOpenSSHVersion(versionStr string) bool { + i := strings.Index(versionStr, openSSHPrefix) + if i < 0 { + return false + } + i += len(openSSHPrefix) + j := i + for ; j < len(versionStr); j++ { + if versionStr[j] < '0' || versionStr[j] > '9' { + break + } + } + version, _ := strconv.Atoi(versionStr[i:j]) + return version < 6 +} + +// autoPortListenWorkaround simulates automatic port allocation by +// trying random ports repeatedly. +func (c *Client) autoPortListenWorkaround(laddr *net.TCPAddr) (net.Listener, error) { + var sshListener net.Listener + var err error + const tries = 10 + for i := 0; i < tries; i++ { + addr := *laddr + addr.Port = 1024 + portRandomizer.Intn(60000) + sshListener, err = c.ListenTCP(&addr) + if err == nil { + laddr.Port = addr.Port + return sshListener, err + } + } + return nil, fmt.Errorf("ssh: listen on random port failed after %d tries: %v", tries, err) +} + +// RFC 4254 7.1 +type channelForwardMsg struct { + addr string + rport uint32 +} + +// handleForwards starts goroutines handling forwarded connections. +// It's called on first use by (*Client).ListenTCP to not launch +// goroutines until needed. +func (c *Client) handleForwards() { + go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-tcpip")) + go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-streamlocal@openssh.com")) +} + +// ListenTCP requests the remote peer open a listening socket +// on laddr. Incoming connections will be available by calling +// Accept on the returned net.Listener. +func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) { + c.handleForwardsOnce.Do(c.handleForwards) + if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) { + return c.autoPortListenWorkaround(laddr) + } + + m := channelForwardMsg{ + laddr.IP.String(), + uint32(laddr.Port), + } + // send message + ok, resp, err := c.SendRequest("tcpip-forward", true, Marshal(&m)) + if err != nil { + return nil, err + } + if !ok { + return nil, errors.New("ssh: tcpip-forward request denied by peer") + } + + // If the original port was 0, then the remote side will + // supply a real port number in the response. + if laddr.Port == 0 { + var p struct { + Port uint32 + } + if err := Unmarshal(resp, &p); err != nil { + return nil, err + } + laddr.Port = int(p.Port) + } + + // Register this forward, using the port number we obtained. + ch := c.forwards.add(laddr) + + return &tcpListener{laddr, c, ch}, nil +} + +// forwardList stores a mapping between remote +// forward requests and the tcpListeners. +type forwardList struct { + sync.Mutex + entries []forwardEntry +} + +// forwardEntry represents an established mapping of a laddr on a +// remote ssh server to a channel connected to a tcpListener. +type forwardEntry struct { + laddr net.Addr + c chan forward +} + +// forward represents an incoming forwarded tcpip connection. The +// arguments to add/remove/lookup should be address as specified in +// the original forward-request. +type forward struct { + newCh NewChannel // the ssh client channel underlying this forward + raddr net.Addr // the raddr of the incoming connection +} + +func (l *forwardList) add(addr net.Addr) chan forward { + l.Lock() + defer l.Unlock() + f := forwardEntry{ + laddr: addr, + c: make(chan forward, 1), + } + l.entries = append(l.entries, f) + return f.c +} + +// See RFC 4254, section 7.2 +type forwardedTCPPayload struct { + Addr string + Port uint32 + OriginAddr string + OriginPort uint32 +} + +// parseTCPAddr parses the originating address from the remote into a *net.TCPAddr. +func parseTCPAddr(addr string, port uint32) (*net.TCPAddr, error) { + if port == 0 || port > 65535 { + return nil, fmt.Errorf("ssh: port number out of range: %d", port) + } + ip := net.ParseIP(string(addr)) + if ip == nil { + return nil, fmt.Errorf("ssh: cannot parse IP address %q", addr) + } + return &net.TCPAddr{IP: ip, Port: int(port)}, nil +} + +func (l *forwardList) handleChannels(in <-chan NewChannel) { + for ch := range in { + var ( + laddr net.Addr + raddr net.Addr + err error + ) + switch channelType := ch.ChannelType(); channelType { + case "forwarded-tcpip": + var payload forwardedTCPPayload + if err = Unmarshal(ch.ExtraData(), &payload); err != nil { + ch.Reject(ConnectionFailed, "could not parse forwarded-tcpip payload: "+err.Error()) + continue + } + + // RFC 4254 section 7.2 specifies that incoming + // addresses should list the address, in string + // format. It is implied that this should be an IP + // address, as it would be impossible to connect to it + // otherwise. + laddr, err = parseTCPAddr(payload.Addr, payload.Port) + if err != nil { + ch.Reject(ConnectionFailed, err.Error()) + continue + } + raddr, err = parseTCPAddr(payload.OriginAddr, payload.OriginPort) + if err != nil { + ch.Reject(ConnectionFailed, err.Error()) + continue + } + + case "forwarded-streamlocal@openssh.com": + var payload forwardedStreamLocalPayload + if err = Unmarshal(ch.ExtraData(), &payload); err != nil { + ch.Reject(ConnectionFailed, "could not parse forwarded-streamlocal@openssh.com payload: "+err.Error()) + continue + } + laddr = &net.UnixAddr{ + Name: payload.SocketPath, + Net: "unix", + } + raddr = &net.UnixAddr{ + Name: "@", + Net: "unix", + } + default: + panic(fmt.Errorf("ssh: unknown channel type %s", channelType)) + } + if ok := l.forward(laddr, raddr, ch); !ok { + // Section 7.2, implementations MUST reject spurious incoming + // connections. + ch.Reject(Prohibited, "no forward for address") + continue + } + + } +} + +// remove removes the forward entry, and the channel feeding its +// listener. +func (l *forwardList) remove(addr net.Addr) { + l.Lock() + defer l.Unlock() + for i, f := range l.entries { + if addr.Network() == f.laddr.Network() && addr.String() == f.laddr.String() { + l.entries = append(l.entries[:i], l.entries[i+1:]...) + close(f.c) + return + } + } +} + +// closeAll closes and clears all forwards. +func (l *forwardList) closeAll() { + l.Lock() + defer l.Unlock() + for _, f := range l.entries { + close(f.c) + } + l.entries = nil +} + +func (l *forwardList) forward(laddr, raddr net.Addr, ch NewChannel) bool { + l.Lock() + defer l.Unlock() + for _, f := range l.entries { + if laddr.Network() == f.laddr.Network() && laddr.String() == f.laddr.String() { + f.c <- forward{newCh: ch, raddr: raddr} + return true + } + } + return false +} + +type tcpListener struct { + laddr *net.TCPAddr + + conn *Client + in <-chan forward +} + +// Accept waits for and returns the next connection to the listener. +func (l *tcpListener) Accept() (net.Conn, error) { + s, ok := <-l.in + if !ok { + return nil, io.EOF + } + ch, incoming, err := s.newCh.Accept() + if err != nil { + return nil, err + } + go DiscardRequests(incoming) + + return &chanConn{ + Channel: ch, + laddr: l.laddr, + raddr: s.raddr, + }, nil +} + +// Close closes the listener. +func (l *tcpListener) Close() error { + m := channelForwardMsg{ + l.laddr.IP.String(), + uint32(l.laddr.Port), + } + + // this also closes the listener. + l.conn.forwards.remove(l.laddr) + ok, _, err := l.conn.SendRequest("cancel-tcpip-forward", true, Marshal(&m)) + if err == nil && !ok { + err = errors.New("ssh: cancel-tcpip-forward failed") + } + return err +} + +// Addr returns the listener's network address. +func (l *tcpListener) Addr() net.Addr { + return l.laddr +} + +// Dial initiates a connection to the addr from the remote host. +// The resulting connection has a zero LocalAddr() and RemoteAddr(). +func (c *Client) Dial(n, addr string) (net.Conn, error) { + var ch Channel + switch n { + case "tcp", "tcp4", "tcp6": + // Parse the address into host and numeric port. + host, portString, err := net.SplitHostPort(addr) + if err != nil { + return nil, err + } + port, err := strconv.ParseUint(portString, 10, 16) + if err != nil { + return nil, err + } + ch, err = c.dial(net.IPv4zero.String(), 0, host, int(port)) + if err != nil { + return nil, err + } + // Use a zero address for local and remote address. + zeroAddr := &net.TCPAddr{ + IP: net.IPv4zero, + Port: 0, + } + return &chanConn{ + Channel: ch, + laddr: zeroAddr, + raddr: zeroAddr, + }, nil + case "unix": + var err error + ch, err = c.dialStreamLocal(addr) + if err != nil { + return nil, err + } + return &chanConn{ + Channel: ch, + laddr: &net.UnixAddr{ + Name: "@", + Net: "unix", + }, + raddr: &net.UnixAddr{ + Name: addr, + Net: "unix", + }, + }, nil + default: + return nil, fmt.Errorf("ssh: unsupported protocol: %s", n) + } +} + +// DialTCP connects to the remote address raddr on the network net, +// which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used +// as the local address for the connection. +func (c *Client) DialTCP(n string, laddr, raddr *net.TCPAddr) (net.Conn, error) { + if laddr == nil { + laddr = &net.TCPAddr{ + IP: net.IPv4zero, + Port: 0, + } + } + ch, err := c.dial(laddr.IP.String(), laddr.Port, raddr.IP.String(), raddr.Port) + if err != nil { + return nil, err + } + return &chanConn{ + Channel: ch, + laddr: laddr, + raddr: raddr, + }, nil +} + +// RFC 4254 7.2 +type channelOpenDirectMsg struct { + raddr string + rport uint32 + laddr string + lport uint32 +} + +func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel, error) { + msg := channelOpenDirectMsg{ + raddr: raddr, + rport: uint32(rport), + laddr: laddr, + lport: uint32(lport), + } + ch, in, err := c.OpenChannel("direct-tcpip", Marshal(&msg)) + if err != nil { + return nil, err + } + go DiscardRequests(in) + return ch, err +} + +type tcpChan struct { + Channel // the backing channel +} + +// chanConn fulfills the net.Conn interface without +// the tcpChan having to hold laddr or raddr directly. +type chanConn struct { + Channel + laddr, raddr net.Addr +} + +// LocalAddr returns the local network address. +func (t *chanConn) LocalAddr() net.Addr { + return t.laddr +} + +// RemoteAddr returns the remote network address. +func (t *chanConn) RemoteAddr() net.Addr { + return t.raddr +} + +// SetDeadline sets the read and write deadlines associated +// with the connection. +func (t *chanConn) SetDeadline(deadline time.Time) error { + if err := t.SetReadDeadline(deadline); err != nil { + return err + } + return t.SetWriteDeadline(deadline) +} + +// SetReadDeadline sets the read deadline. +// A zero value for t means Read will not time out. +// After the deadline, the error from Read will implement net.Error +// with Timeout() == true. +func (t *chanConn) SetReadDeadline(deadline time.Time) error { + // for compatibility with previous version, + // the error message contains "tcpChan" + return errors.New("ssh: tcpChan: deadline not supported") +} + +// SetWriteDeadline exists to satisfy the net.Conn interface +// but is not implemented by this type. It always returns an error. +func (t *chanConn) SetWriteDeadline(deadline time.Time) error { + return errors.New("ssh: tcpChan: deadline not supported") +} diff --git a/vendor/golang.org/x/crypto/ssh/transport.go b/vendor/golang.org/x/crypto/ssh/transport.go new file mode 100644 index 00000000..49ddc2e7 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/transport.go @@ -0,0 +1,353 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package ssh + +import ( + "bufio" + "bytes" + "errors" + "io" + "log" +) + +// debugTransport if set, will print packet types as they go over the +// wire. No message decoding is done, to minimize the impact on timing. +const debugTransport = false + +const ( + gcmCipherID = "aes128-gcm@openssh.com" + aes128cbcID = "aes128-cbc" + tripledescbcID = "3des-cbc" +) + +// packetConn represents a transport that implements packet based +// operations. +type packetConn interface { + // Encrypt and send a packet of data to the remote peer. + writePacket(packet []byte) error + + // Read a packet from the connection. The read is blocking, + // i.e. if error is nil, then the returned byte slice is + // always non-empty. + readPacket() ([]byte, error) + + // Close closes the write-side of the connection. + Close() error +} + +// transport is the keyingTransport that implements the SSH packet +// protocol. +type transport struct { + reader connectionState + writer connectionState + + bufReader *bufio.Reader + bufWriter *bufio.Writer + rand io.Reader + isClient bool + io.Closer +} + +// packetCipher represents a combination of SSH encryption/MAC +// protocol. A single instance should be used for one direction only. +type packetCipher interface { + // writeCipherPacket encrypts the packet and writes it to w. The + // contents of the packet are generally scrambled. + writeCipherPacket(seqnum uint32, w io.Writer, rand io.Reader, packet []byte) error + + // readCipherPacket reads and decrypts a packet of data. The + // returned packet may be overwritten by future calls of + // readPacket. + readCipherPacket(seqnum uint32, r io.Reader) ([]byte, error) +} + +// connectionState represents one side (read or write) of the +// connection. This is necessary because each direction has its own +// keys, and can even have its own algorithms +type connectionState struct { + packetCipher + seqNum uint32 + dir direction + pendingKeyChange chan packetCipher +} + +// prepareKeyChange sets up key material for a keychange. The key changes in +// both directions are triggered by reading and writing a msgNewKey packet +// respectively. +func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error { + ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult) + if err != nil { + return err + } + t.reader.pendingKeyChange <- ciph + + ciph, err = newPacketCipher(t.writer.dir, algs.w, kexResult) + if err != nil { + return err + } + t.writer.pendingKeyChange <- ciph + + return nil +} + +func (t *transport) printPacket(p []byte, write bool) { + if len(p) == 0 { + return + } + who := "server" + if t.isClient { + who = "client" + } + what := "read" + if write { + what = "write" + } + + log.Println(what, who, p[0]) +} + +// Read and decrypt next packet. +func (t *transport) readPacket() (p []byte, err error) { + for { + p, err = t.reader.readPacket(t.bufReader) + if err != nil { + break + } + if len(p) == 0 || (p[0] != msgIgnore && p[0] != msgDebug) { + break + } + } + if debugTransport { + t.printPacket(p, false) + } + + return p, err +} + +func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) { + packet, err := s.packetCipher.readCipherPacket(s.seqNum, r) + s.seqNum++ + if err == nil && len(packet) == 0 { + err = errors.New("ssh: zero length packet") + } + + if len(packet) > 0 { + switch packet[0] { + case msgNewKeys: + select { + case cipher := <-s.pendingKeyChange: + s.packetCipher = cipher + default: + return nil, errors.New("ssh: got bogus newkeys message") + } + + case msgDisconnect: + // Transform a disconnect message into an + // error. Since this is lowest level at which + // we interpret message types, doing it here + // ensures that we don't have to handle it + // elsewhere. + var msg disconnectMsg + if err := Unmarshal(packet, &msg); err != nil { + return nil, err + } + return nil, &msg + } + } + + // The packet may point to an internal buffer, so copy the + // packet out here. + fresh := make([]byte, len(packet)) + copy(fresh, packet) + + return fresh, err +} + +func (t *transport) writePacket(packet []byte) error { + if debugTransport { + t.printPacket(packet, true) + } + return t.writer.writePacket(t.bufWriter, t.rand, packet) +} + +func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte) error { + changeKeys := len(packet) > 0 && packet[0] == msgNewKeys + + err := s.packetCipher.writeCipherPacket(s.seqNum, w, rand, packet) + if err != nil { + return err + } + if err = w.Flush(); err != nil { + return err + } + s.seqNum++ + if changeKeys { + select { + case cipher := <-s.pendingKeyChange: + s.packetCipher = cipher + default: + panic("ssh: no key material for msgNewKeys") + } + } + return err +} + +func newTransport(rwc io.ReadWriteCloser, rand io.Reader, isClient bool) *transport { + t := &transport{ + bufReader: bufio.NewReader(rwc), + bufWriter: bufio.NewWriter(rwc), + rand: rand, + reader: connectionState{ + packetCipher: &streamPacketCipher{cipher: noneCipher{}}, + pendingKeyChange: make(chan packetCipher, 1), + }, + writer: connectionState{ + packetCipher: &streamPacketCipher{cipher: noneCipher{}}, + pendingKeyChange: make(chan packetCipher, 1), + }, + Closer: rwc, + } + t.isClient = isClient + + if isClient { + t.reader.dir = serverKeys + t.writer.dir = clientKeys + } else { + t.reader.dir = clientKeys + t.writer.dir = serverKeys + } + + return t +} + +type direction struct { + ivTag []byte + keyTag []byte + macKeyTag []byte +} + +var ( + serverKeys = direction{[]byte{'B'}, []byte{'D'}, []byte{'F'}} + clientKeys = direction{[]byte{'A'}, []byte{'C'}, []byte{'E'}} +) + +// setupKeys sets the cipher and MAC keys from kex.K, kex.H and sessionId, as +// described in RFC 4253, section 6.4. direction should either be serverKeys +// (to setup server->client keys) or clientKeys (for client->server keys). +func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) { + cipherMode := cipherModes[algs.Cipher] + macMode := macModes[algs.MAC] + + iv := make([]byte, cipherMode.ivSize) + key := make([]byte, cipherMode.keySize) + macKey := make([]byte, macMode.keySize) + + generateKeyMaterial(iv, d.ivTag, kex) + generateKeyMaterial(key, d.keyTag, kex) + generateKeyMaterial(macKey, d.macKeyTag, kex) + + return cipherModes[algs.Cipher].create(key, iv, macKey, algs) +} + +// generateKeyMaterial fills out with key material generated from tag, K, H +// and sessionId, as specified in RFC 4253, section 7.2. +func generateKeyMaterial(out, tag []byte, r *kexResult) { + var digestsSoFar []byte + + h := r.Hash.New() + for len(out) > 0 { + h.Reset() + h.Write(r.K) + h.Write(r.H) + + if len(digestsSoFar) == 0 { + h.Write(tag) + h.Write(r.SessionID) + } else { + h.Write(digestsSoFar) + } + + digest := h.Sum(nil) + n := copy(out, digest) + out = out[n:] + if len(out) > 0 { + digestsSoFar = append(digestsSoFar, digest...) + } + } +} + +const packageVersion = "SSH-2.0-Go" + +// Sends and receives a version line. The versionLine string should +// be US ASCII, start with "SSH-2.0-", and should not include a +// newline. exchangeVersions returns the other side's version line. +func exchangeVersions(rw io.ReadWriter, versionLine []byte) (them []byte, err error) { + // Contrary to the RFC, we do not ignore lines that don't + // start with "SSH-2.0-" to make the library usable with + // nonconforming servers. + for _, c := range versionLine { + // The spec disallows non US-ASCII chars, and + // specifically forbids null chars. + if c < 32 { + return nil, errors.New("ssh: junk character in version line") + } + } + if _, err = rw.Write(append(versionLine, '\r', '\n')); err != nil { + return + } + + them, err = readVersion(rw) + return them, err +} + +// maxVersionStringBytes is the maximum number of bytes that we'll +// accept as a version string. RFC 4253 section 4.2 limits this at 255 +// chars +const maxVersionStringBytes = 255 + +// Read version string as specified by RFC 4253, section 4.2. +func readVersion(r io.Reader) ([]byte, error) { + versionString := make([]byte, 0, 64) + var ok bool + var buf [1]byte + + for length := 0; length < maxVersionStringBytes; length++ { + _, err := io.ReadFull(r, buf[:]) + if err != nil { + return nil, err + } + // The RFC says that the version should be terminated with \r\n + // but several SSH servers actually only send a \n. + if buf[0] == '\n' { + if !bytes.HasPrefix(versionString, []byte("SSH-")) { + // RFC 4253 says we need to ignore all version string lines + // except the one containing the SSH version (provided that + // all the lines do not exceed 255 bytes in total). + versionString = versionString[:0] + continue + } + ok = true + break + } + + // non ASCII chars are disallowed, but we are lenient, + // since Go doesn't use null-terminated strings. + + // The RFC allows a comment after a space, however, + // all of it (version and comments) goes into the + // session hash. + versionString = append(versionString, buf[0]) + } + + if !ok { + return nil, errors.New("ssh: overflow reading version string") + } + + // There might be a '\r' on the end which we should remove. + if len(versionString) > 0 && versionString[len(versionString)-1] == '\r' { + versionString = versionString[:len(versionString)-1] + } + return versionString, nil +}