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TUN-4017: Add support for using cloudflared as a full socks proxy.

To use cloudflared as a socks proxy, add an ingress on the server
side with your desired rules. Rules are matched in the order they
are added.  If there are no rules, it is an implicit allow.  If
there are rules, but no rule matches match, the connection is denied.

ingress:
  - hostname: socks.example.com
    service: socks-proxy
    originRequest:
      ipRules:
        - prefix: 1.1.1.1/24
          ports: [80, 443]
          allow: true
        - prefix: 0.0.0.0/0
          allow: false

On the client, run using tcp mode:
cloudflared access tcp --hostname socks.example.com --url 127.0.0.1:8080

Set your socks proxy as 127.0.0.1:8080 and you will now be proxying
all connections to the remote machine.
pull/171/merge
Lee Valentine 1 year ago
parent
commit
206523344f
  1. 8
      config/configuration.go
  2. 19
      ingress/ingress.go
  3. 38
      ingress/ingress_test.go
  4. 16
      ingress/origin_connection.go
  5. 11
      ingress/origin_proxy.go
  6. 3
      ingress/origin_request_config.go
  7. 23
      ingress/origin_service.go
  8. 101
      ipaccess/access.go
  9. 107
      ipaccess/access_test.go
  10. 2
      socks/connection_handler_test.go
  11. 40
      socks/request_handler.go
  12. 58
      socks/request_handler_test.go

8
config/configuration.go

@ -221,6 +221,14 @@ type OriginRequestConfig struct {
ProxyPort *uint `yaml:"proxyPort"`
// Valid options are 'socks' or empty.
ProxyType *string `yaml:"proxyType"`
// IP rules for the proxy service
IPRules []IngressIPRule `yaml:"ipRules"`
}
type IngressIPRule struct {
Prefix *string `yaml:"prefix"`
Ports []int `yaml:"ports"`
Allow bool `yaml:"allow"`
}
type Configuration struct {

19
ingress/ingress.go

@ -10,6 +10,7 @@ import (
"sync"
"github.com/cloudflare/cloudflared/config"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/pkg/errors"
"github.com/rs/zerolog"
@ -26,6 +27,7 @@ var (
const (
ServiceBastion = "bastion"
ServiceSocksProxy = "socks-proxy"
ServiceWarpRouting = "warp-routing"
)
@ -175,6 +177,23 @@ func validate(ingress []config.UnvalidatedIngressRule, defaults OriginRequestCon
service = &srv
} else if r.Service == "hello_world" || r.Service == "hello-world" || r.Service == "helloworld" {
service = new(helloWorld)
} else if r.Service == ServiceSocksProxy {
rules := make([]ipaccess.Rule, len(r.OriginRequest.IPRules))
for i, ipRule := range r.OriginRequest.IPRules {
rule, err := ipaccess.NewRuleByCIDR(ipRule.Prefix, ipRule.Ports, ipRule.Allow)
if err != nil {
return Ingress{}, fmt.Errorf("unable to create ip rule for %s: %s", r.Service, err)
}
rules[i] = rule
}
accessPolicy, err := ipaccess.NewPolicy(false, rules)
if err != nil {
return Ingress{}, fmt.Errorf("unable to create ip access policy for %s: %s", r.Service, err)
}
service = newSocksProxyOverWSService(accessPolicy)
} else if r.Service == ServiceBastion || cfg.BastionMode {
// Bastion mode will always start a Websocket proxy server, which will
// overwrite the localService.URL field when `start` is called. So,

38
ingress/ingress_test.go

@ -15,6 +15,7 @@ import (
"gopkg.in/yaml.v2"
"github.com/cloudflare/cloudflared/config"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/cloudflare/cloudflared/tlsconfig"
)
@ -304,6 +305,33 @@ ingress:
},
},
},
{
name: "SOCKS services",
args: args{rawYAML: `
ingress:
- hostname: socks.foo.com
service: socks-proxy
originRequest:
ipRules:
- prefix: 1.1.1.0/24
ports: [80, 443]
allow: true
- prefix: 0.0.0.0/0
allow: false
- service: http_status:404
`},
want: []Rule{
{
Hostname: "socks.foo.com",
Service: newSocksProxyOverWSService(accessPolicy()),
Config: defaultConfig,
},
{
Service: &fourOhFour,
Config: defaultConfig,
},
},
},
{
name: "URL isn't necessary if using bastion",
args: args{rawYAML: `
@ -548,6 +576,16 @@ func MustParseURL(t *testing.T, rawURL string) *url.URL {
return u
}
func accessPolicy() *ipaccess.Policy {
cidr1 := "1.1.1.0/24"
cidr2 := "0.0.0.0/0"
rule1, _ := ipaccess.NewRuleByCIDR(&cidr1, []int{80, 443}, true)
rule2, _ := ipaccess.NewRuleByCIDR(&cidr2, nil, false)
rules := []ipaccess.Rule{rule1, rule2}
accessPolicy, _ := ipaccess.NewPolicy(false, rules)
return accessPolicy
}
func BenchmarkFindMatch(b *testing.B) {
rulesYAML := `
ingress:

16
ingress/origin_connection.go

@ -7,6 +7,8 @@ import (
"net"
"net/http"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/cloudflare/cloudflared/socks"
"github.com/cloudflare/cloudflared/websocket"
gws "github.com/gorilla/websocket"
"github.com/rs/zerolog"
@ -107,3 +109,17 @@ func newWSConnection(clientTLSConfig *tls.Config, r *http.Request) (OriginConnec
resp,
}, resp, nil
}
// socksProxyOverWSConnection is an OriginConnection that streams SOCKS connections over WS.
// The connection to the origin happens inside the SOCKS code as the client specifies the origin
// details in the packet.
type socksProxyOverWSConnection struct {
accessPolicy *ipaccess.Policy
}
func (sp *socksProxyOverWSConnection) Stream(ctx context.Context, tunnelConn io.ReadWriter, log *zerolog.Logger) {
socks.StreamNetHandler(websocket.NewConn(ctx, tunnelConn, log), sp.accessPolicy, log)
}
func (sp *socksProxyOverWSConnection) Close() {
}

11
ingress/origin_proxy.go

@ -145,3 +145,14 @@ func (o *tcpOverWSService) bastionDest(r *http.Request) (string, error) {
func removePath(dest string) string {
return strings.SplitN(dest, "/", 2)[0]
}
func (o *socksProxyOverWSService) EstablishConnection(r *http.Request) (OriginConnection, *http.Response, error) {
originConn := o.conn
resp := &http.Response{
Status: switchingProtocolText,
StatusCode: http.StatusSwitchingProtocols,
Header: websocket.NewResponseHeader(r),
ContentLength: -1,
}
return originConn, resp, nil
}

3
ingress/origin_request_config.go

@ -3,6 +3,7 @@ package ingress
import (
"time"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/urfave/cli/v2"
"github.com/cloudflare/cloudflared/config"
@ -213,6 +214,8 @@ type OriginRequestConfig struct {
ProxyPort uint `yaml:"proxyPort"`
// What sort of proxy should be started
ProxyType string `yaml:"proxyType"`
// IP rules for the proxy service
IPRules []ipaccess.Rule `yaml:"ipRules"`
}
func (defaults *OriginRequestConfig) setConnectTimeout(overrides config.OriginRequestConfig) {

23
ingress/origin_service.go

@ -12,6 +12,7 @@ import (
"time"
"github.com/cloudflare/cloudflared/hello"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/cloudflare/cloudflared/socks"
"github.com/cloudflare/cloudflared/tlsconfig"
"github.com/cloudflare/cloudflared/websocket"
@ -100,6 +101,10 @@ type tcpOverWSService struct {
streamHandler streamHandlerFunc
}
type socksProxyOverWSService struct {
conn *socksProxyOverWSConnection
}
func newTCPOverWSService(url *url.URL) *tcpOverWSService {
switch url.Scheme {
case "ssh":
@ -122,6 +127,16 @@ func newBastionService() *tcpOverWSService {
}
}
func newSocksProxyOverWSService(accessPolicy *ipaccess.Policy) *socksProxyOverWSService {
proxy := socksProxyOverWSService{
conn: &socksProxyOverWSConnection{
accessPolicy: accessPolicy,
},
}
return &proxy
}
func addPortIfMissing(uri *url.URL, port int) {
if uri.Port() == "" {
uri.Host = fmt.Sprintf("%s:%d", uri.Hostname(), port)
@ -144,6 +159,14 @@ func (o *tcpOverWSService) start(wg *sync.WaitGroup, log *zerolog.Logger, shutdo
return nil
}
func (o *socksProxyOverWSService) start(wg *sync.WaitGroup, log *zerolog.Logger, shutdownC <-chan struct{}, errC chan error, cfg OriginRequestConfig) error {
return nil
}
func (o *socksProxyOverWSService) String() string {
return ServiceSocksProxy
}
// HelloWorld is an OriginService for the built-in Hello World server.
// Users only use this for testing and experimenting with cloudflared.
type helloWorld struct {

101
ipaccess/access.go

@ -0,0 +1,101 @@
package ipaccess
import (
"fmt"
"net"
"sort"
)
type Policy struct {
defaultAllow bool
rules []Rule
}
type Rule struct {
ipNet *net.IPNet
ports []int
allow bool
}
func NewPolicy(defaultAllow bool, rules []Rule) (*Policy, error) {
for _, rule := range rules {
if err := rule.Validate(); err != nil {
return nil, err
}
}
policy := Policy{
defaultAllow: defaultAllow,
rules: rules,
}
return &policy, nil
}
func NewRuleByCIDR(prefix *string, ports []int, allow bool) (Rule, error) {
if prefix == nil || len(*prefix) == 0 {
return Rule{}, fmt.Errorf("no prefix provided")
}
_, ipnet, err := net.ParseCIDR(*prefix)
if err != nil {
return Rule{}, fmt.Errorf("unable to parse cidr: %s", *prefix)
}
return NewRule(ipnet, ports, allow)
}
func NewRule(ipnet *net.IPNet, ports []int, allow bool) (Rule, error) {
rule := Rule{
ipNet: ipnet,
ports: ports,
allow: allow,
}
return rule, rule.Validate()
}
func (r *Rule) Validate() error {
if r.ipNet == nil {
return fmt.Errorf("no ipnet set on the rule")
}
if len(r.ports) > 0 {
sort.Ints(r.ports)
for _, port := range r.ports {
if port < 1 || port > 65535 {
return fmt.Errorf("invalid port %d, needs to be between 1 and 65535", port)
}
}
}
return nil
}
func (h *Policy) Allowed(ip net.IP, port int) (bool, *Rule) {
if len(h.rules) == 0 {
return h.defaultAllow, nil
}
for _, rule := range h.rules {
if rule.ipNet.Contains(ip) {
if len(rule.ports) == 0 {
return rule.allow, &rule
} else if pos := sort.SearchInts(rule.ports, port); pos < len(rule.ports) && rule.ports[pos] == port {
return rule.allow, &rule
}
}
}
return h.defaultAllow, nil
}
func (ipr *Rule) String() string {
return fmt.Sprintf("prefix:%s/port:%s/allow:%t", ipr.ipNet, ipr.PortsString(), ipr.allow)
}
func (ipr *Rule) PortsString() string {
if len(ipr.ports) > 0 {
return fmt.Sprint(ipr.ports)
}
return "all"
}

107
ipaccess/access_test.go

@ -0,0 +1,107 @@
package ipaccess
import (
"bytes"
"net"
"testing"
"github.com/stretchr/testify/assert"
)
func TestRuleCreation(t *testing.T) {
_, ipnet, _ := net.ParseCIDR("1.1.1.1/24")
_, err := NewRule(nil, []int{80}, false)
assert.Error(t, err, "expected error as no ipnet provided")
_, err = NewRule(ipnet, []int{65536, 80}, false)
assert.Error(t, err, "expected error as port higher than 65535")
_, err = NewRule(ipnet, []int{80, -1}, false)
assert.Error(t, err, "expected error as port less than 0")
rule, err := NewRule(ipnet, []int{443, 80}, false)
assert.NoError(t, err)
assert.True(t, ipnet.IP.Equal(rule.ipNet.IP) && bytes.Compare(ipnet.Mask, rule.ipNet.Mask) == 0, "ipnet expected to be %+v, got: %+v", ipnet, rule.ipNet)
assert.True(t, len(rule.ports) == 2 && rule.ports[0] == 80 && rule.ports[1] == 443, "expected ports to be sorted")
}
func TestRuleCreationByCIDR(t *testing.T) {
var cidr *string
_, err := NewRuleByCIDR(cidr, []int{80}, false)
assert.Error(t, err, "expected error as cidr is nil")
badCidr := "1.1.1.1"
cidr = &badCidr
_, err = NewRuleByCIDR(cidr, []int{80}, false)
assert.Error(t, err, "expected error as the cidr is bad")
goodCidr := "1.1.1.1/24"
_, ipnet, _ := net.ParseCIDR("1.1.1.0/24")
cidr = &goodCidr
rule, err := NewRuleByCIDR(cidr, []int{80}, false)
assert.NoError(t, err)
assert.True(t, ipnet.IP.Equal(rule.ipNet.IP) && bytes.Compare(ipnet.Mask, rule.ipNet.Mask) == 0, "ipnet expected to be %+v, got: %+v", ipnet, rule.ipNet)
}
func TestRulesNoRules(t *testing.T) {
ip, _, _ := net.ParseCIDR("1.2.3.4/24")
policy, _ := NewPolicy(true, []Rule{})
allowed, rule := policy.Allowed(ip, 80)
assert.True(t, allowed, "expected to be allowed as no rules and default allow")
assert.Nil(t, rule, "expected to be nil as no rules")
policy, _ = NewPolicy(false, []Rule{})
allowed, rule = policy.Allowed(ip, 80)
assert.False(t, allowed, "expected to be denied as no rules and default deny")
assert.Nil(t, rule, "expected to be nil as no rules")
}
func TestRulesMatchIPAndPort(t *testing.T) {
ip1, ipnet1, _ := net.ParseCIDR("1.2.3.4/24")
ip2, _, _ := net.ParseCIDR("2.3.4.5/24")
rule1, _ := NewRule(ipnet1, []int{80, 443}, true)
rules := []Rule{
rule1,
}
policy, _ := NewPolicy(false, rules)
allowed, rule := policy.Allowed(ip1, 80)
assert.True(t, allowed, "expected to be allowed as matching rule")
assert.True(t, rule.ipNet == ipnet1, "expected to match ipnet1")
allowed, rule = policy.Allowed(ip2, 80)
assert.False(t, allowed, "expected to be denied as no matching rule")
assert.Nil(t, rule, "expected to be nil")
}
func TestRulesMatchIPAndPort2(t *testing.T) {
ip1, ipnet1, _ := net.ParseCIDR("1.2.3.4/24")
ip2, ipnet2, _ := net.ParseCIDR("2.3.4.5/24")
rule1, _ := NewRule(ipnet1, []int{53, 80}, false)
rule2, _ := NewRule(ipnet2, []int{53, 80}, true)
rules := []Rule{
rule1,
rule2,
}
policy, _ := NewPolicy(false, rules)
allowed, rule := policy.Allowed(ip1, 80)
assert.False(t, allowed, "expected to be denied as matching rule")
assert.True(t, rule.ipNet == ipnet1, "expected to match ipnet1")
allowed, rule = policy.Allowed(ip2, 80)
assert.True(t, allowed, "expected to be allowed as matching rule")
assert.True(t, rule.ipNet == ipnet2, "expected to match ipnet1")
allowed, rule = policy.Allowed(ip2, 81)
assert.False(t, allowed, "expected to be denied as no matching rule")
assert.Nil(t, rule, "expected to be nil")
}

2
socks/connection_handler_test.go

@ -40,7 +40,7 @@ func sendSocksRequest(t *testing.T) []byte {
func startTestServer(t *testing.T, httpHandler func(w http.ResponseWriter, r *http.Request)) {
// create a socks server
requestHandler := NewRequestHandler(NewNetDialer())
requestHandler := NewRequestHandler(NewNetDialer(), nil)
socksServer := NewConnectionHandler(requestHandler)
listener, err := net.Listen("tcp", "localhost:8086")
assert.NoError(t, err)

40
socks/request_handler.go

@ -6,6 +6,7 @@ import (
"net"
"strings"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/rs/zerolog"
)
@ -16,14 +17,16 @@ type RequestHandler interface {
// StandardRequestHandler implements the base socks5 command processing
type StandardRequestHandler struct {
dialer Dialer
dialer Dialer
accessPolicy *ipaccess.Policy
}
// NewRequestHandler creates a standard SOCKS5 request handler
// This handles the SOCKS5 commands and proxies them to their destination
func NewRequestHandler(dialer Dialer) RequestHandler {
func NewRequestHandler(dialer Dialer, accessPolicy *ipaccess.Policy) RequestHandler {
return &StandardRequestHandler{
dialer: dialer,
dialer: dialer,
accessPolicy: accessPolicy,
}
}
@ -46,6 +49,25 @@ func (h *StandardRequestHandler) Handle(req *Request, conn io.ReadWriter) error
// handleConnect is used to handle a connect command
func (h *StandardRequestHandler) handleConnect(conn io.ReadWriter, req *Request) error {
if h.accessPolicy != nil {
if req.DestAddr.IP == nil {
addr, err := net.ResolveIPAddr("ip", req.DestAddr.FQDN)
if err != nil {
_ = sendReply(conn, ruleFailure, req.DestAddr)
return fmt.Errorf("unable to resolve host to confirm acceess")
}
req.DestAddr.IP = addr.IP
}
if allowed, rule := h.accessPolicy.Allowed(req.DestAddr.IP, req.DestAddr.Port); !allowed {
_ = sendReply(conn, ruleFailure, req.DestAddr)
if rule != nil {
return fmt.Errorf("Connect to %v denied due to iprule: %s", req.DestAddr, rule.String())
}
return fmt.Errorf("Connect to %v denied", req.DestAddr)
}
}
target, localAddr, err := h.dialer.Dial(req.DestAddr.Address())
if err != nil {
msg := err.Error()
@ -110,7 +132,17 @@ func (h *StandardRequestHandler) handleAssociate(conn io.ReadWriter, req *Reques
func StreamHandler(tunnelConn io.ReadWriter, originConn net.Conn, log *zerolog.Logger) {
dialer := NewConnDialer(originConn)
requestHandler := NewRequestHandler(dialer)
requestHandler := NewRequestHandler(dialer, nil)
socksServer := NewConnectionHandler(requestHandler)
if err := socksServer.Serve(tunnelConn); err != nil {
log.Debug().Err(err).Msg("Socks stream handler error")
}
}
func StreamNetHandler(tunnelConn io.ReadWriter, accessPolicy *ipaccess.Policy, log *zerolog.Logger) {
dialer := NewNetDialer()
requestHandler := NewRequestHandler(dialer, accessPolicy)
socksServer := NewConnectionHandler(requestHandler)
if err := socksServer.Serve(tunnelConn); err != nil {

58
socks/request_handler_test.go

@ -4,6 +4,7 @@ import (
"bytes"
"testing"
"github.com/cloudflare/cloudflared/ipaccess"
"github.com/stretchr/testify/assert"
)
@ -11,7 +12,7 @@ func TestUnsupportedBind(t *testing.T) {
req := createRequest(t, socks5Version, bindCommand, "2001:db8::68", 1337, false)
var b bytes.Buffer
requestHandler := NewRequestHandler(NewNetDialer())
requestHandler := NewRequestHandler(NewNetDialer(), nil)
err := requestHandler.Handle(req, &b)
assert.NoError(t, err)
assert.True(t, b.Bytes()[1] == commandNotSupported, "expected a response")
@ -21,8 +22,61 @@ func TestUnsupportedAssociate(t *testing.T) {
req := createRequest(t, socks5Version, associateCommand, "127.0.0.1", 1337, false)
var b bytes.Buffer
requestHandler := NewRequestHandler(NewNetDialer())
requestHandler := NewRequestHandler(NewNetDialer(), nil)
err := requestHandler.Handle(req, &b)
assert.NoError(t, err)
assert.True(t, b.Bytes()[1] == commandNotSupported, "expected a response")
}
func TestHandleConnect(t *testing.T) {
req := createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1337, false)
var b bytes.Buffer
requestHandler := NewRequestHandler(NewNetDialer(), nil)
err := requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == connectionRefused, "expected a response")
}
func TestHandleConnectIPAccess(t *testing.T) {
prefix := "127.0.0.0/24"
rule1, _ := ipaccess.NewRuleByCIDR(&prefix, []int{1337}, true)
rule2, _ := ipaccess.NewRuleByCIDR(&prefix, []int{1338}, false)
rules := []ipaccess.Rule{rule1, rule2}
var b bytes.Buffer
accessPolicy, _ := ipaccess.NewPolicy(false, nil)
requestHandler := NewRequestHandler(NewNetDialer(), accessPolicy)
req := createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1337, false)
err := requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == ruleFailure, "expected to be denied as no rules and defaultAllow=false")
b.Reset()
accessPolicy, _ = ipaccess.NewPolicy(true, nil)
requestHandler = NewRequestHandler(NewNetDialer(), accessPolicy)
req = createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1337, false)
err = requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == connectionRefused, "expected to be allowed as no rules and defaultAllow=true")
b.Reset()
accessPolicy, _ = ipaccess.NewPolicy(false, rules)
requestHandler = NewRequestHandler(NewNetDialer(), accessPolicy)
req = createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1337, false)
err = requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == connectionRefused, "expected to be allowed as matching rule")
b.Reset()
req = createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1338, false)
err = requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == ruleFailure, "expected to be denied as matching rule")
b.Reset()
req = createRequest(t, socks5Version, connectCommand, "127.0.0.1", 1339, false)
err = requestHandler.Handle(req, &b)
assert.Error(t, err)
assert.True(t, b.Bytes()[1] == ruleFailure, "expect to be denied as no matching rule and defaultAllow=false")
}

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