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AUTH-1557: Short Lived Certs

This commit is contained in:
Austin Cherry 2019-01-23 15:42:10 -06:00
parent 14f50d0922
commit fa17b0200f
36 changed files with 10286 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
.gitignore vendored
View File

@ -9,3 +9,4 @@ guide/public
\#*\#
cscope.*
cloudflared
!cmd/cloudflared/

5
Gopkg.lock generated
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@ -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",

53
carrier/carrier.go
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@ -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
}

14
carrier/carrier_test.go
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@ -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)
}

33
cmd/cloudflared/access/carrier.go
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@ -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 {

33
cmd/cloudflared/access/cmd.go
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@ -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.",
},
},
},

30
cmd/cloudflared/path/path.go Normal file
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@ -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
}

36
cmd/cloudflared/token/token.go
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@ -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
}

163
sshgen/sshgen.go Normal file
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@ -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)
}

308
vendor/golang.org/x/crypto/internal/chacha20/asm_arm64.s generated vendored Normal file
View File

@ -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

31
vendor/golang.org/x/crypto/internal/chacha20/chacha_arm64.go generated vendored Normal file
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// 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])
}
}

264
vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go generated vendored Normal file
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// 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
}

16
vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go generated vendored Normal file
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// 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")
}

29
vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go generated vendored Normal file
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// 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()

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vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.s generated vendored Normal file
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// 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

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vendor/golang.org/x/crypto/internal/chacha20/xor.go generated vendored Normal file
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// 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)
}
}

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vendor/golang.org/x/crypto/ssh/buffer.go generated vendored Normal file
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// 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
}

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vendor/golang.org/x/crypto/ssh/certs.go generated vendored Normal file
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// 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
}

633
vendor/golang.org/x/crypto/ssh/channel.go generated vendored Normal file
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// 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
}

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vendor/golang.org/x/crypto/ssh/cipher.go generated vendored Normal file
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// 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
}

278
vendor/golang.org/x/crypto/ssh/client.go generated vendored Normal file
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@ -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
}
}

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// 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}
}

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// 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()
}

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// 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)
}

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// 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"

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// 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
}

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// 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
}

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vendor/golang.org/x/crypto/ssh/keys.go generated vendored Normal file
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vendor/golang.org/x/crypto/ssh/mac.go generated vendored Normal file
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// 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)}
}},
}

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// 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",
}

330
vendor/golang.org/x/crypto/ssh/mux.go generated vendored Normal file
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// 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)
}
}

594
vendor/golang.org/x/crypto/ssh/server.go generated vendored Normal file
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// 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
}

647
vendor/golang.org/x/crypto/ssh/session.go generated vendored Normal file
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@ -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
}

116
vendor/golang.org/x/crypto/ssh/streamlocal.go generated vendored Normal file
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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",
}
}

474
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// 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")
}

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vendor/golang.org/x/crypto/ssh/transport.go generated vendored Normal file
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// 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
}