[tor-commits] [flashproxy/master] Move pt.go to a pt package.
dcf at torproject.org
dcf at torproject.org
Mon Aug 12 02:32:20 UTC 2013
commit 39161f03a3836f71ed861b82a2dd6103bb01d192
Author: David Fifield <david at bamsoftware.com>
Date: Mon Jun 24 22:48:32 2013 -0700
Move pt.go to a pt package.
---
websocket-transport/Makefile | 4 +-
websocket-transport/pt.go | 603 -------------------------------
websocket-transport/pt/pt.go | 602 ++++++++++++++++++++++++++++++
websocket-transport/websocket-client.go | 10 +-
websocket-transport/websocket-server.go | 14 +-
5 files changed, 618 insertions(+), 615 deletions(-)
diff --git a/websocket-transport/Makefile b/websocket-transport/Makefile
index a4131eb..6a6b8a7 100644
--- a/websocket-transport/Makefile
+++ b/websocket-transport/Makefile
@@ -11,8 +11,8 @@ GOBUILDFLAGS =
all: websocket-server
-websocket-client: websocket-client.go socks.go pt.go
-websocket-server: websocket-server.go pt.go websocket.go
+websocket-client: websocket-client.go socks.go
+websocket-server: websocket-server.go websocket.go
%: %.go
go build $(GOBUILDFLAGS) -o $@ $^
diff --git a/websocket-transport/pt.go b/websocket-transport/pt.go
deleted file mode 100644
index 1319198..0000000
--- a/websocket-transport/pt.go
+++ /dev/null
@@ -1,603 +0,0 @@
-// Tor pluggable transports library.
-//
-// Sample client usage:
-//
-// PtClientSetup([]string{"foo"})
-// ln, err := startSocksListener()
-// if err != nil {
-// panic(err.Error())
-// }
-// PtCmethod("foo", "socks4", ln.Addr())
-// PtCmethodsDone()
-//
-// Sample server usage:
-//
-// var ptInfo PtServerInfo
-// info = PtServerSetup([]string{"foo", "bar"})
-// for _, bindAddr := range info.BindAddrs {
-// ln, err := startListener(bindAddr.Addr)
-// if err != nil {
-// PtSmethodError(bindAddr.MethodName, err.Error())
-// }
-// PtSmethod(bindAddr.MethodName, ln.Addr())
-// }
-// PtSmethodsDone()
-// func handler(conn net.Conn) {
-// or, err := PtConnectOr(&ptInfo, ws.Conn)
-// if err != nil {
-// return
-// }
-// // Do something with or and conn.
-// }
-
-package main
-
-import (
- "bufio"
- "bytes"
- "crypto/hmac"
- "crypto/rand"
- "crypto/sha256"
- "crypto/subtle"
- "encoding/binary"
- "errors"
- "fmt"
- "io"
- "net"
- "os"
- "strings"
- "time"
-)
-
-func getenv(key string) string {
- return os.Getenv(key)
-}
-
-// Abort with an ENV-ERROR if the environment variable isn't set.
-func getenvRequired(key string) string {
- value := os.Getenv(key)
- if value == "" {
- PtEnvError(fmt.Sprintf("no %s environment variable", key))
- }
- return value
-}
-
-// Escape a string so it contains no byte values over 127 and doesn't contain
-// any of the characters '\x00', '\n', or '\\'.
-func escape(s string) string {
- var buf bytes.Buffer
- for _, b := range []byte(s) {
- if b == '\n' {
- buf.WriteString("\\n")
- } else if b == '\\' {
- buf.WriteString("\\\\")
- } else if 0 < b && b < 128 {
- buf.WriteByte(b)
- } else {
- fmt.Fprintf(&buf, "\\x%02x", b)
- }
- }
- return buf.String()
-}
-
-// Print a pluggable transports protocol line to stdout. The line consists of an
-// unescaped keyword, followed by any number of escaped strings.
-func PtLine(keyword string, v ...string) {
- var buf bytes.Buffer
- buf.WriteString(keyword)
- for _, x := range v {
- buf.WriteString(" " + escape(x))
- }
- fmt.Println(buf.String())
- os.Stdout.Sync()
-}
-
-// All of the Pt*Error functions call os.Exit(1).
-
-// Emit an ENV-ERROR with explanation text.
-func PtEnvError(msg string) {
- PtLine("ENV-ERROR", msg)
- os.Exit(1)
-}
-
-// Emit a VERSION-ERROR with explanation text.
-func PtVersionError(msg string) {
- PtLine("VERSION-ERROR", msg)
- os.Exit(1)
-}
-
-// Emit a CMETHOD-ERROR with explanation text.
-func PtCmethodError(methodName, msg string) {
- PtLine("CMETHOD-ERROR", methodName, msg)
- os.Exit(1)
-}
-
-// Emit an SMETHOD-ERROR with explanation text.
-func PtSmethodError(methodName, msg string) {
- PtLine("SMETHOD-ERROR", methodName, msg)
- os.Exit(1)
-}
-
-// Emit a CMETHOD line. socks must be "socks4" or "socks5". Call this once for
-// each listening client SOCKS port.
-func PtCmethod(name string, socks string, addr net.Addr) {
- PtLine("CMETHOD", name, socks, addr.String())
-}
-
-// Emit a CMETHODS DONE line. Call this after opening all client listeners.
-func PtCmethodsDone() {
- PtLine("CMETHODS", "DONE")
-}
-
-// Emit an SMETHOD line. Call this once for each listening server port.
-func PtSmethod(name string, addr net.Addr) {
- PtLine("SMETHOD", name, addr.String())
-}
-
-// Emit an SMETHODS DONE line. Call this after opening all server listeners.
-func PtSmethodsDone() {
- PtLine("SMETHODS", "DONE")
-}
-
-// Get a pluggable transports version offered by Tor and understood by us, if
-// any. The only version we understand is "1". This function reads the
-// environment variable TOR_PT_MANAGED_TRANSPORT_VER.
-func getManagedTransportVer() string {
- const transportVersion = "1"
- for _, offered := range strings.Split(getenvRequired("TOR_PT_MANAGED_TRANSPORT_VER"), ",") {
- if offered == transportVersion {
- return offered
- }
- }
- return ""
-}
-
-// Get the intersection of the method names offered by Tor and those in
-// methodNames. This function reads the environment variable
-// TOR_PT_CLIENT_TRANSPORTS.
-func getClientTransports(methodNames []string) []string {
- clientTransports := getenvRequired("TOR_PT_CLIENT_TRANSPORTS")
- if clientTransports == "*" {
- return methodNames
- }
- result := make([]string, 0)
- for _, requested := range strings.Split(clientTransports, ",") {
- for _, methodName := range methodNames {
- if requested == methodName {
- result = append(result, methodName)
- break
- }
- }
- }
- return result
-}
-
-// This structure is returned by PtClientSetup. It consists of a list of method
-// names.
-type PtClientInfo struct {
- MethodNames []string
-}
-
-// Check the client pluggable transports environments, emitting an error message
-// and exiting the program if any error is encountered. Returns a subset of
-// methodNames requested by Tor.
-func PtClientSetup(methodNames []string) PtClientInfo {
- var info PtClientInfo
-
- ver := getManagedTransportVer()
- if ver == "" {
- PtVersionError("no-version")
- } else {
- PtLine("VERSION", ver)
- }
-
- info.MethodNames = getClientTransports(methodNames)
- if len(info.MethodNames) == 0 {
- PtCmethodsDone()
- os.Exit(1)
- }
-
- return info
-}
-
-// A combination of a method name and an address, as extracted from
-// TOR_PT_SERVER_BINDADDR.
-type PtBindAddr struct {
- MethodName string
- Addr *net.TCPAddr
-}
-
-// Resolve an address string into a net.TCPAddr.
-func resolveBindAddr(bindAddr string) (*net.TCPAddr, error) {
- addr, err := net.ResolveTCPAddr("tcp", bindAddr)
- if err == nil {
- return addr, nil
- }
- // Before the fixing of bug #7011, tor doesn't put brackets around IPv6
- // addresses. Split after the last colon, assuming it is a port
- // separator, and try adding the brackets.
- parts := strings.Split(bindAddr, ":")
- if len(parts) <= 2 {
- return nil, err
- }
- bindAddr = "[" + strings.Join(parts[:len(parts)-1], ":") + "]:" + parts[len(parts)-1]
- return net.ResolveTCPAddr("tcp", bindAddr)
-}
-
-// Return a new slice, the members of which are those members of addrs having a
-// MethodName in methodsNames.
-func filterBindAddrs(addrs []PtBindAddr, methodNames []string) []PtBindAddr {
- var result []PtBindAddr
-
- for _, ba := range addrs {
- for _, methodName := range methodNames {
- if ba.MethodName == methodName {
- result = append(result, ba)
- break
- }
- }
- }
-
- return result
-}
-
-// Return a map from method names to bind addresses. The map is the contents of
-// TOR_PT_SERVER_BINDADDR, with keys filtered by TOR_PT_SERVER_TRANSPORTS, and
-// further filtered by the methods in methodNames.
-func getServerBindAddrs(methodNames []string) []PtBindAddr {
- var result []PtBindAddr
-
- // Get the list of all requested bindaddrs.
- var serverBindAddr = getenvRequired("TOR_PT_SERVER_BINDADDR")
- for _, spec := range strings.Split(serverBindAddr, ",") {
- var bindAddr PtBindAddr
-
- parts := strings.SplitN(spec, "-", 2)
- if len(parts) != 2 {
- PtEnvError(fmt.Sprintf("TOR_PT_SERVER_BINDADDR: %q: doesn't contain \"-\"", spec))
- }
- bindAddr.MethodName = parts[0]
- addr, err := resolveBindAddr(parts[1])
- if err != nil {
- PtEnvError(fmt.Sprintf("TOR_PT_SERVER_BINDADDR: %q: %s", spec, err.Error()))
- }
- bindAddr.Addr = addr
- result = append(result, bindAddr)
- }
-
- // Filter by TOR_PT_SERVER_TRANSPORTS.
- serverTransports := getenvRequired("TOR_PT_SERVER_TRANSPORTS")
- if serverTransports != "*" {
- result = filterBindAddrs(result, strings.Split(serverTransports, ","))
- }
-
- // Finally filter by what we understand.
- result = filterBindAddrs(result, methodNames)
-
- return result
-}
-
-// Reads and validates the contents of an auth cookie file. Returns the 32-byte
-// cookie. See section 4.2.1.2 of pt-spec.txt.
-func readAuthCookieFile(filename string) ([]byte, error) {
- authCookieHeader := []byte("! Extended ORPort Auth Cookie !\x0a")
- header := make([]byte, 32)
- cookie := make([]byte, 32)
-
- f, err := os.Open(filename)
- if err != nil {
- return cookie, err
- }
- defer f.Close()
-
- n, err := io.ReadFull(f, header)
- if err != nil {
- return cookie, err
- }
- n, err = io.ReadFull(f, cookie)
- if err != nil {
- return cookie, err
- }
- // Check that the file ends here.
- n, err = f.Read(make([]byte, 1))
- if n != 0 {
- return cookie, errors.New(fmt.Sprintf("file is longer than 64 bytes"))
- } else if err != io.EOF {
- return cookie, errors.New(fmt.Sprintf("did not find EOF at end of file"))
- }
-
- if !bytes.Equal(header, authCookieHeader) {
- return cookie, errors.New(fmt.Sprintf("missing auth cookie header"))
- }
-
- return cookie, nil
-}
-
-// This structure is returned by PtServerSetup. It consists of a list of
-// PtBindAddrs, along with a single address for the ORPort.
-type PtServerInfo struct {
- BindAddrs []PtBindAddr
- OrAddr *net.TCPAddr
- ExtendedOrAddr *net.TCPAddr
- AuthCookie []byte
-}
-
-// Check the server pluggable transports environments, emitting an error message
-// and exiting the program if any error is encountered. Resolves the various
-// requested bind addresses and the server ORPort. Returns a PtServerInfo
-// struct.
-func PtServerSetup(methodNames []string) PtServerInfo {
- var info PtServerInfo
- var err error
-
- ver := getManagedTransportVer()
- if ver == "" {
- PtVersionError("no-version")
- } else {
- PtLine("VERSION", ver)
- }
-
- var orPort = getenvRequired("TOR_PT_ORPORT")
- info.OrAddr, err = net.ResolveTCPAddr("tcp", orPort)
- if err != nil {
- PtEnvError(fmt.Sprintf("cannot resolve TOR_PT_ORPORT %q: %s", orPort, err.Error()))
- }
-
- info.BindAddrs = getServerBindAddrs(methodNames)
- if len(info.BindAddrs) == 0 {
- PtSmethodsDone()
- os.Exit(1)
- }
-
- var extendedOrPort = getenv("TOR_PT_EXTENDED_SERVER_PORT")
- if extendedOrPort != "" {
- info.ExtendedOrAddr, err = net.ResolveTCPAddr("tcp", extendedOrPort)
- if err != nil {
- PtEnvError(fmt.Sprintf("cannot resolve TOR_PT_EXTENDED_SERVER_PORT %q: %s", extendedOrPort, err.Error()))
- }
- }
-
- var authCookieFilename = getenv("TOR_PT_AUTH_COOKIE_FILE")
- if authCookieFilename != "" {
- info.AuthCookie, err = readAuthCookieFile(authCookieFilename)
- if err != nil {
- PtEnvError(fmt.Sprintf("error reading TOR_PT_AUTH_COOKIE_FILE %q: %s", authCookieFilename, err.Error()))
- }
- }
-
- return info
-}
-
-// See 217-ext-orport-auth.txt section 4.2.1.3.
-func computeServerHash(info *PtServerInfo, clientNonce, serverNonce []byte) []byte {
- h := hmac.New(sha256.New, info.AuthCookie)
- io.WriteString(h, "ExtORPort authentication server-to-client hash")
- h.Write(clientNonce)
- h.Write(serverNonce)
- return h.Sum([]byte{})
-}
-
-// See 217-ext-orport-auth.txt section 4.2.1.3.
-func computeClientHash(info *PtServerInfo, clientNonce, serverNonce []byte) []byte {
- h := hmac.New(sha256.New, info.AuthCookie)
- io.WriteString(h, "ExtORPort authentication client-to-server hash")
- h.Write(clientNonce)
- h.Write(serverNonce)
- return h.Sum([]byte{})
-}
-
-func extOrPortAuthenticate(s *net.TCPConn, info *PtServerInfo) error {
- r := bufio.NewReader(s)
-
- // Read auth types. 217-ext-orport-auth.txt section 4.1.
- var authTypes [256]bool
- var count int
- for count = 0; count < 256; count++ {
- b, err := r.ReadByte()
- if err != nil {
- return err
- }
- if b == 0 {
- break
- }
- authTypes[b] = true
- }
- if count >= 256 {
- return errors.New(fmt.Sprintf("read 256 auth types without seeing \\x00"))
- }
-
- // We support only type 1, SAFE_COOKIE.
- if !authTypes[1] {
- return errors.New(fmt.Sprintf("server didn't offer auth type 1"))
- }
- _, err := s.Write([]byte{1})
- if err != nil {
- return err
- }
-
- clientNonce := make([]byte, 32)
- clientHash := make([]byte, 32)
- serverNonce := make([]byte, 32)
- serverHash := make([]byte, 32)
-
- _, err = io.ReadFull(rand.Reader, clientNonce)
- if err != nil {
- return err
- }
- _, err = s.Write(clientNonce)
- if err != nil {
- return err
- }
-
- _, err = io.ReadFull(r, serverHash)
- if err != nil {
- return err
- }
- _, err = io.ReadFull(r, serverNonce)
- if err != nil {
- return err
- }
-
- expectedServerHash := computeServerHash(info, clientNonce, serverNonce)
- if subtle.ConstantTimeCompare(serverHash, expectedServerHash) != 1 {
- return errors.New(fmt.Sprintf("mismatch in server hash"))
- }
-
- clientHash = computeClientHash(info, clientNonce, serverNonce)
- _, err = s.Write(clientHash)
- if err != nil {
- return err
- }
-
- status := make([]byte, 1)
- _, err = io.ReadFull(r, status)
- if err != nil {
- return err
- }
- if status[0] != 1 {
- return errors.New(fmt.Sprintf("server rejected authentication"))
- }
-
- if r.Buffered() != 0 {
- return errors.New(fmt.Sprintf("%d bytes left after extended OR port authentication", r.Buffered()))
- }
-
- return nil
-}
-
-// See section 3.1 of 196-transport-control-ports.txt.
-const (
- extOrCmdDone = 0x0000
- extOrCmdUserAddr = 0x0001
- extOrCmdTransport = 0x0002
- extOrCmdOkay = 0x1000
- extOrCmdDeny = 0x1001
-)
-
-func extOrPortWriteCommand(s *net.TCPConn, cmd uint16, body []byte) error {
- var buf bytes.Buffer
- if len(body) > 65535 {
- return errors.New("command exceeds maximum length of 65535")
- }
- err := binary.Write(&buf, binary.BigEndian, cmd)
- if err != nil {
- return err
- }
- err = binary.Write(&buf, binary.BigEndian, uint16(len(body)))
- if err != nil {
- return err
- }
- err = binary.Write(&buf, binary.BigEndian, body)
- if err != nil {
- return err
- }
- _, err = s.Write(buf.Bytes())
- if err != nil {
- return err
- }
-
- return nil
-}
-
-// Send a USERADDR command on s. See section 3.1.2.1 of
-// 196-transport-control-ports.txt.
-func extOrPortSendUserAddr(s *net.TCPConn, conn net.Conn) error {
- return extOrPortWriteCommand(s, extOrCmdUserAddr, []byte(conn.RemoteAddr().String()))
-}
-
-// Send a TRANSPORT command on s. See section 3.1.2.2 of
-// 196-transport-control-ports.txt.
-func extOrPortSendTransport(s *net.TCPConn, methodName string) error {
- return extOrPortWriteCommand(s, extOrCmdTransport, []byte(methodName))
-}
-
-// Send a DONE command on s. See section 3.1 of 196-transport-control-ports.txt.
-func extOrPortSendDone(s *net.TCPConn) error {
- return extOrPortWriteCommand(s, extOrCmdDone, []byte{})
-}
-
-func extOrPortRecvCommand(s *net.TCPConn) (cmd uint16, body []byte, err error) {
- var bodyLen uint16
- data := make([]byte, 4)
-
- _, err = io.ReadFull(s, data)
- if err != nil {
- return
- }
- buf := bytes.NewBuffer(data)
- err = binary.Read(buf, binary.BigEndian, &cmd)
- if err != nil {
- return
- }
- err = binary.Read(buf, binary.BigEndian, &bodyLen)
- if err != nil {
- return
- }
- body = make([]byte, bodyLen)
- _, err = io.ReadFull(s, body)
- if err != nil {
- return
- }
-
- return cmd, body, err
-}
-
-// Send USERADDR and TRANSPORT commands followed by a DONE command. Wait for an
-// OKAY or DENY response command from the server. Returns nil if and only if
-// OKAY is received.
-func extOrPortSetup(s *net.TCPConn, conn net.Conn, methodName string) error {
- var err error
-
- err = extOrPortSendUserAddr(s, conn)
- if err != nil {
- return err
- }
- err = extOrPortSendTransport(s, methodName)
- if err != nil {
- return err
- }
- err = extOrPortSendDone(s)
- if err != nil {
- return err
- }
- cmd, _, err := extOrPortRecvCommand(s)
- if err != nil {
- return err
- }
- if cmd == extOrCmdDeny {
- return errors.New("server returned DENY after our USERADDR and DONE")
- } else if cmd != extOrCmdOkay {
- return errors.New(fmt.Sprintf("server returned unknown command 0x%04x after our USERADDR and DONE", cmd))
- }
-
- return nil
-}
-
-// Connect to info.ExtendedOrAddr if defined, or else info.OrAddr, and return an
-// open *net.TCPConn. If connecting to the extended OR port, extended OR port
-// authentication à la 217-ext-orport-auth.txt is done before returning; an
-// error is returned if authentication fails.
-func PtConnectOr(info *PtServerInfo, conn net.Conn, methodName string) (*net.TCPConn, error) {
- if info.ExtendedOrAddr == nil {
- return net.DialTCP("tcp", nil, info.OrAddr)
- }
-
- s, err := net.DialTCP("tcp", nil, info.ExtendedOrAddr)
- if err != nil {
- return nil, err
- }
- s.SetDeadline(time.Now().Add(5 * time.Second))
- err = extOrPortAuthenticate(s, info)
- if err != nil {
- s.Close()
- return nil, err
- }
- err = extOrPortSetup(s, conn, methodName)
- if err != nil {
- s.Close()
- return nil, err
- }
- s.SetDeadline(time.Time{})
-
- return s, nil
-}
diff --git a/websocket-transport/pt/pt.go b/websocket-transport/pt/pt.go
new file mode 100644
index 0000000..60e4507
--- /dev/null
+++ b/websocket-transport/pt/pt.go
@@ -0,0 +1,602 @@
+// Tor pluggable transports library.
+//
+// Sample client usage:
+//
+// pt.ClientSetup([]string{"foo"})
+// ln, err := startSocksListener()
+// if err != nil {
+// panic(err.Error())
+// }
+// pt.Cmethod("foo", "socks4", ln.Addr())
+// pt.CmethodsDone()
+//
+// Sample server usage:
+//
+// var ptInfo pt.ServerInfo
+// info = pt.ServerSetup([]string{"foo", "bar"})
+// for _, bindAddr := range info.BindAddrs {
+// ln, err := startListener(bindAddr.Addr)
+// if err != nil {
+// pt.SmethodError(bindAddr.MethodName, err.Error())
+// }
+// pt.Smethod(bindAddr.MethodName, ln.Addr())
+// }
+// pt.SmethodsDone()
+// func handler(conn net.Conn) {
+// or, err := pt.ConnectOr(&ptInfo, ws.Conn)
+// if err != nil {
+// return
+// }
+// // Do something with or and conn.
+// }
+
+package pt
+
+import (
+ "bufio"
+ "bytes"
+ "crypto/hmac"
+ "crypto/rand"
+ "crypto/sha256"
+ "crypto/subtle"
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+ "net"
+ "os"
+ "strings"
+ "time"
+)
+
+func getenv(key string) string {
+ return os.Getenv(key)
+}
+
+// Abort with an ENV-ERROR if the environment variable isn't set.
+func getenvRequired(key string) string {
+ value := os.Getenv(key)
+ if value == "" {
+ EnvError(fmt.Sprintf("no %s environment variable", key))
+ }
+ return value
+}
+
+// Escape a string so it contains no byte values over 127 and doesn't contain
+// any of the characters '\x00', '\n', or '\\'.
+func escape(s string) string {
+ var buf bytes.Buffer
+ for _, b := range []byte(s) {
+ if b == '\n' {
+ buf.WriteString("\\n")
+ } else if b == '\\' {
+ buf.WriteString("\\\\")
+ } else if 0 < b && b < 128 {
+ buf.WriteByte(b)
+ } else {
+ fmt.Fprintf(&buf, "\\x%02x", b)
+ }
+ }
+ return buf.String()
+}
+
+// Print a pluggable transports protocol line to stdout. The line consists of an
+// unescaped keyword, followed by any number of escaped strings.
+func Line(keyword string, v ...string) {
+ var buf bytes.Buffer
+ buf.WriteString(keyword)
+ for _, x := range v {
+ buf.WriteString(" " + escape(x))
+ }
+ fmt.Println(buf.String())
+ os.Stdout.Sync()
+}
+
+// All of the *Error functions call os.Exit(1).
+
+// Emit an ENV-ERROR with explanation text.
+func EnvError(msg string) {
+ Line("ENV-ERROR", msg)
+ os.Exit(1)
+}
+
+// Emit a VERSION-ERROR with explanation text.
+func VersionError(msg string) {
+ Line("VERSION-ERROR", msg)
+ os.Exit(1)
+}
+
+// Emit a CMETHOD-ERROR with explanation text.
+func CmethodError(methodName, msg string) {
+ Line("CMETHOD-ERROR", methodName, msg)
+ os.Exit(1)
+}
+
+// Emit an SMETHOD-ERROR with explanation text.
+func SmethodError(methodName, msg string) {
+ Line("SMETHOD-ERROR", methodName, msg)
+ os.Exit(1)
+}
+
+// Emit a CMETHOD line. socks must be "socks4" or "socks5". Call this once for
+// each listening client SOCKS port.
+func Cmethod(name string, socks string, addr net.Addr) {
+ Line("CMETHOD", name, socks, addr.String())
+}
+
+// Emit a CMETHODS DONE line. Call this after opening all client listeners.
+func CmethodsDone() {
+ Line("CMETHODS", "DONE")
+}
+
+// Emit an SMETHOD line. Call this once for each listening server port.
+func Smethod(name string, addr net.Addr) {
+ Line("SMETHOD", name, addr.String())
+}
+
+// Emit an SMETHODS DONE line. Call this after opening all server listeners.
+func SmethodsDone() {
+ Line("SMETHODS", "DONE")
+}
+
+// Get a pluggable transports version offered by Tor and understood by us, if
+// any. The only version we understand is "1". This function reads the
+// environment variable TOR_PT_MANAGED_TRANSPORT_VER.
+func getManagedTransportVer() string {
+ const transportVersion = "1"
+ for _, offered := range strings.Split(getenvRequired("TOR_PT_MANAGED_TRANSPORT_VER"), ",") {
+ if offered == transportVersion {
+ return offered
+ }
+ }
+ return ""
+}
+
+// Get the intersection of the method names offered by Tor and those in
+// methodNames. This function reads the environment variable
+// TOR_PT_CLIENT_TRANSPORTS.
+func getClientTransports(methodNames []string) []string {
+ clientTransports := getenvRequired("TOR_PT_CLIENT_TRANSPORTS")
+ if clientTransports == "*" {
+ return methodNames
+ }
+ result := make([]string, 0)
+ for _, requested := range strings.Split(clientTransports, ",") {
+ for _, methodName := range methodNames {
+ if requested == methodName {
+ result = append(result, methodName)
+ break
+ }
+ }
+ }
+ return result
+}
+
+// This structure is returned by ClientSetup. It consists of a list of method
+// names.
+type ClientInfo struct {
+ MethodNames []string
+}
+
+// Check the client pluggable transports environments, emitting an error message
+// and exiting the program if any error is encountered. Returns a subset of
+// methodNames requested by Tor.
+func ClientSetup(methodNames []string) ClientInfo {
+ var info ClientInfo
+
+ ver := getManagedTransportVer()
+ if ver == "" {
+ VersionError("no-version")
+ } else {
+ Line("VERSION", ver)
+ }
+
+ info.MethodNames = getClientTransports(methodNames)
+ if len(info.MethodNames) == 0 {
+ CmethodsDone()
+ os.Exit(1)
+ }
+
+ return info
+}
+
+// A combination of a method name and an address, as extracted from
+// TOR_PT_SERVER_BINDADDR.
+type BindAddr struct {
+ MethodName string
+ Addr *net.TCPAddr
+}
+
+// Resolve an address string into a net.TCPAddr.
+func resolveBindAddr(bindAddr string) (*net.TCPAddr, error) {
+ addr, err := net.ResolveTCPAddr("tcp", bindAddr)
+ if err == nil {
+ return addr, nil
+ }
+ // Before the fixing of bug #7011, tor doesn't put brackets around IPv6
+ // addresses. Split after the last colon, assuming it is a port
+ // separator, and try adding the brackets.
+ parts := strings.Split(bindAddr, ":")
+ if len(parts) <= 2 {
+ return nil, err
+ }
+ bindAddr = "[" + strings.Join(parts[:len(parts)-1], ":") + "]:" + parts[len(parts)-1]
+ return net.ResolveTCPAddr("tcp", bindAddr)
+}
+
+// Return a new slice, the members of which are those members of addrs having a
+// MethodName in methodsNames.
+func filterBindAddrs(addrs []BindAddr, methodNames []string) []BindAddr {
+ var result []BindAddr
+
+ for _, ba := range addrs {
+ for _, methodName := range methodNames {
+ if ba.MethodName == methodName {
+ result = append(result, ba)
+ break
+ }
+ }
+ }
+
+ return result
+}
+
+// Return a map from method names to bind addresses. The map is the contents of
+// TOR_PT_SERVER_BINDADDR, with keys filtered by TOR_PT_SERVER_TRANSPORTS, and
+// further filtered by the methods in methodNames.
+func getServerBindAddrs(methodNames []string) []BindAddr {
+ var result []BindAddr
+
+ // Get the list of all requested bindaddrs.
+ var serverBindAddr = getenvRequired("TOR_PT_SERVER_BINDADDR")
+ for _, spec := range strings.Split(serverBindAddr, ",") {
+ var bindAddr BindAddr
+
+ parts := strings.SplitN(spec, "-", 2)
+ if len(parts) != 2 {
+ EnvError(fmt.Sprintf("TOR_PT_SERVER_BINDADDR: %q: doesn't contain \"-\"", spec))
+ }
+ bindAddr.MethodName = parts[0]
+ addr, err := resolveBindAddr(parts[1])
+ if err != nil {
+ EnvError(fmt.Sprintf("TOR_PT_SERVER_BINDADDR: %q: %s", spec, err.Error()))
+ }
+ bindAddr.Addr = addr
+ result = append(result, bindAddr)
+ }
+
+ // Filter by TOR_PT_SERVER_TRANSPORTS.
+ serverTransports := getenvRequired("TOR_PT_SERVER_TRANSPORTS")
+ if serverTransports != "*" {
+ result = filterBindAddrs(result, strings.Split(serverTransports, ","))
+ }
+
+ // Finally filter by what we understand.
+ result = filterBindAddrs(result, methodNames)
+
+ return result
+}
+
+// Reads and validates the contents of an auth cookie file. Returns the 32-byte
+// cookie. See section 4.2.1.2 of pt-spec.txt.
+func readAuthCookieFile(filename string) ([]byte, error) {
+ authCookieHeader := []byte("! Extended ORPort Auth Cookie !\x0a")
+ header := make([]byte, 32)
+ cookie := make([]byte, 32)
+
+ f, err := os.Open(filename)
+ if err != nil {
+ return cookie, err
+ }
+ defer f.Close()
+
+ n, err := io.ReadFull(f, header)
+ if err != nil {
+ return cookie, err
+ }
+ n, err = io.ReadFull(f, cookie)
+ if err != nil {
+ return cookie, err
+ }
+ // Check that the file ends here.
+ n, err = f.Read(make([]byte, 1))
+ if n != 0 {
+ return cookie, errors.New(fmt.Sprintf("file is longer than 64 bytes"))
+ } else if err != io.EOF {
+ return cookie, errors.New(fmt.Sprintf("did not find EOF at end of file"))
+ }
+
+ if !bytes.Equal(header, authCookieHeader) {
+ return cookie, errors.New(fmt.Sprintf("missing auth cookie header"))
+ }
+
+ return cookie, nil
+}
+
+// This structure is returned by ServerSetup. It consists of a list of
+// BindAddrs, along with a single address for the ORPort.
+type ServerInfo struct {
+ BindAddrs []BindAddr
+ OrAddr *net.TCPAddr
+ ExtendedOrAddr *net.TCPAddr
+ AuthCookie []byte
+}
+
+// Check the server pluggable transports environments, emitting an error message
+// and exiting the program if any error is encountered. Resolves the various
+// requested bind addresses and the server ORPort. Returns a ServerInfo struct.
+func ServerSetup(methodNames []string) ServerInfo {
+ var info ServerInfo
+ var err error
+
+ ver := getManagedTransportVer()
+ if ver == "" {
+ VersionError("no-version")
+ } else {
+ Line("VERSION", ver)
+ }
+
+ var orPort = getenvRequired("TOR_PT_ORPORT")
+ info.OrAddr, err = net.ResolveTCPAddr("tcp", orPort)
+ if err != nil {
+ EnvError(fmt.Sprintf("cannot resolve TOR_PT_ORPORT %q: %s", orPort, err.Error()))
+ }
+
+ info.BindAddrs = getServerBindAddrs(methodNames)
+ if len(info.BindAddrs) == 0 {
+ SmethodsDone()
+ os.Exit(1)
+ }
+
+ var extendedOrPort = getenv("TOR_PT_EXTENDED_SERVER_PORT")
+ if extendedOrPort != "" {
+ info.ExtendedOrAddr, err = net.ResolveTCPAddr("tcp", extendedOrPort)
+ if err != nil {
+ EnvError(fmt.Sprintf("cannot resolve TOR_PT_EXTENDED_SERVER_PORT %q: %s", extendedOrPort, err.Error()))
+ }
+ }
+
+ var authCookieFilename = getenv("TOR_PT_AUTH_COOKIE_FILE")
+ if authCookieFilename != "" {
+ info.AuthCookie, err = readAuthCookieFile(authCookieFilename)
+ if err != nil {
+ EnvError(fmt.Sprintf("error reading TOR_PT_AUTH_COOKIE_FILE %q: %s", authCookieFilename, err.Error()))
+ }
+ }
+
+ return info
+}
+
+// See 217-ext-orport-auth.txt section 4.2.1.3.
+func computeServerHash(info *ServerInfo, clientNonce, serverNonce []byte) []byte {
+ h := hmac.New(sha256.New, info.AuthCookie)
+ io.WriteString(h, "ExtORPort authentication server-to-client hash")
+ h.Write(clientNonce)
+ h.Write(serverNonce)
+ return h.Sum([]byte{})
+}
+
+// See 217-ext-orport-auth.txt section 4.2.1.3.
+func computeClientHash(info *ServerInfo, clientNonce, serverNonce []byte) []byte {
+ h := hmac.New(sha256.New, info.AuthCookie)
+ io.WriteString(h, "ExtORPort authentication client-to-server hash")
+ h.Write(clientNonce)
+ h.Write(serverNonce)
+ return h.Sum([]byte{})
+}
+
+func extOrPortAuthenticate(s *net.TCPConn, info *ServerInfo) error {
+ r := bufio.NewReader(s)
+
+ // Read auth types. 217-ext-orport-auth.txt section 4.1.
+ var authTypes [256]bool
+ var count int
+ for count = 0; count < 256; count++ {
+ b, err := r.ReadByte()
+ if err != nil {
+ return err
+ }
+ if b == 0 {
+ break
+ }
+ authTypes[b] = true
+ }
+ if count >= 256 {
+ return errors.New(fmt.Sprintf("read 256 auth types without seeing \\x00"))
+ }
+
+ // We support only type 1, SAFE_COOKIE.
+ if !authTypes[1] {
+ return errors.New(fmt.Sprintf("server didn't offer auth type 1"))
+ }
+ _, err := s.Write([]byte{1})
+ if err != nil {
+ return err
+ }
+
+ clientNonce := make([]byte, 32)
+ clientHash := make([]byte, 32)
+ serverNonce := make([]byte, 32)
+ serverHash := make([]byte, 32)
+
+ _, err = io.ReadFull(rand.Reader, clientNonce)
+ if err != nil {
+ return err
+ }
+ _, err = s.Write(clientNonce)
+ if err != nil {
+ return err
+ }
+
+ _, err = io.ReadFull(r, serverHash)
+ if err != nil {
+ return err
+ }
+ _, err = io.ReadFull(r, serverNonce)
+ if err != nil {
+ return err
+ }
+
+ expectedServerHash := computeServerHash(info, clientNonce, serverNonce)
+ if subtle.ConstantTimeCompare(serverHash, expectedServerHash) != 1 {
+ return errors.New(fmt.Sprintf("mismatch in server hash"))
+ }
+
+ clientHash = computeClientHash(info, clientNonce, serverNonce)
+ _, err = s.Write(clientHash)
+ if err != nil {
+ return err
+ }
+
+ status := make([]byte, 1)
+ _, err = io.ReadFull(r, status)
+ if err != nil {
+ return err
+ }
+ if status[0] != 1 {
+ return errors.New(fmt.Sprintf("server rejected authentication"))
+ }
+
+ if r.Buffered() != 0 {
+ return errors.New(fmt.Sprintf("%d bytes left after extended OR port authentication", r.Buffered()))
+ }
+
+ return nil
+}
+
+// See section 3.1 of 196-transport-control-ports.txt.
+const (
+ extOrCmdDone = 0x0000
+ extOrCmdUserAddr = 0x0001
+ extOrCmdTransport = 0x0002
+ extOrCmdOkay = 0x1000
+ extOrCmdDeny = 0x1001
+)
+
+func extOrPortWriteCommand(s *net.TCPConn, cmd uint16, body []byte) error {
+ var buf bytes.Buffer
+ if len(body) > 65535 {
+ return errors.New("command exceeds maximum length of 65535")
+ }
+ err := binary.Write(&buf, binary.BigEndian, cmd)
+ if err != nil {
+ return err
+ }
+ err = binary.Write(&buf, binary.BigEndian, uint16(len(body)))
+ if err != nil {
+ return err
+ }
+ err = binary.Write(&buf, binary.BigEndian, body)
+ if err != nil {
+ return err
+ }
+ _, err = s.Write(buf.Bytes())
+ if err != nil {
+ return err
+ }
+
+ return nil
+}
+
+// Send a USERADDR command on s. See section 3.1.2.1 of
+// 196-transport-control-ports.txt.
+func extOrPortSendUserAddr(s *net.TCPConn, conn net.Conn) error {
+ return extOrPortWriteCommand(s, extOrCmdUserAddr, []byte(conn.RemoteAddr().String()))
+}
+
+// Send a TRANSPORT command on s. See section 3.1.2.2 of
+// 196-transport-control-ports.txt.
+func extOrPortSendTransport(s *net.TCPConn, methodName string) error {
+ return extOrPortWriteCommand(s, extOrCmdTransport, []byte(methodName))
+}
+
+// Send a DONE command on s. See section 3.1 of 196-transport-control-ports.txt.
+func extOrPortSendDone(s *net.TCPConn) error {
+ return extOrPortWriteCommand(s, extOrCmdDone, []byte{})
+}
+
+func extOrPortRecvCommand(s *net.TCPConn) (cmd uint16, body []byte, err error) {
+ var bodyLen uint16
+ data := make([]byte, 4)
+
+ _, err = io.ReadFull(s, data)
+ if err != nil {
+ return
+ }
+ buf := bytes.NewBuffer(data)
+ err = binary.Read(buf, binary.BigEndian, &cmd)
+ if err != nil {
+ return
+ }
+ err = binary.Read(buf, binary.BigEndian, &bodyLen)
+ if err != nil {
+ return
+ }
+ body = make([]byte, bodyLen)
+ _, err = io.ReadFull(s, body)
+ if err != nil {
+ return
+ }
+
+ return cmd, body, err
+}
+
+// Send USERADDR and TRANSPORT commands followed by a DONE command. Wait for an
+// OKAY or DENY response command from the server. Returns nil if and only if
+// OKAY is received.
+func extOrPortSetup(s *net.TCPConn, conn net.Conn, methodName string) error {
+ var err error
+
+ err = extOrPortSendUserAddr(s, conn)
+ if err != nil {
+ return err
+ }
+ err = extOrPortSendTransport(s, methodName)
+ if err != nil {
+ return err
+ }
+ err = extOrPortSendDone(s)
+ if err != nil {
+ return err
+ }
+ cmd, _, err := extOrPortRecvCommand(s)
+ if err != nil {
+ return err
+ }
+ if cmd == extOrCmdDeny {
+ return errors.New("server returned DENY after our USERADDR and DONE")
+ } else if cmd != extOrCmdOkay {
+ return errors.New(fmt.Sprintf("server returned unknown command 0x%04x after our USERADDR and DONE", cmd))
+ }
+
+ return nil
+}
+
+// Connect to info.ExtendedOrAddr if defined, or else info.OrAddr, and return an
+// open *net.TCPConn. If connecting to the extended OR port, extended OR port
+// authentication à la 217-ext-orport-auth.txt is done before returning; an
+// error is returned if authentication fails.
+func ConnectOr(info *ServerInfo, conn net.Conn, methodName string) (*net.TCPConn, error) {
+ if info.ExtendedOrAddr == nil {
+ return net.DialTCP("tcp", nil, info.OrAddr)
+ }
+
+ s, err := net.DialTCP("tcp", nil, info.ExtendedOrAddr)
+ if err != nil {
+ return nil, err
+ }
+ s.SetDeadline(time.Now().Add(5 * time.Second))
+ err = extOrPortAuthenticate(s, info)
+ if err != nil {
+ s.Close()
+ return nil, err
+ }
+ err = extOrPortSetup(s, conn, methodName)
+ if err != nil {
+ s.Close()
+ return nil, err
+ }
+ s.SetDeadline(time.Time{})
+
+ return s, nil
+}
diff --git a/websocket-transport/websocket-client.go b/websocket-transport/websocket-client.go
index 15b70dc..20e0c7b 100644
--- a/websocket-transport/websocket-client.go
+++ b/websocket-transport/websocket-client.go
@@ -18,6 +18,8 @@ import (
"time"
)
+import "./pt"
+
const ptMethodName = "websocket"
const socksTimeout = 2 * time.Second
const bufSiz = 1500
@@ -205,19 +207,19 @@ func main() {
}
Log("starting")
- PtClientSetup([]string{ptMethodName})
+ pt.ClientSetup([]string{ptMethodName})
listeners := make([]*net.TCPListener, 0)
for _, socksAddrStr := range socksAddrStrs {
ln, err := startListener(socksAddrStr)
if err != nil {
- PtCmethodError(ptMethodName, err.Error())
+ pt.CmethodError(ptMethodName, err.Error())
}
- PtCmethod(ptMethodName, "socks4", ln.Addr())
+ pt.Cmethod(ptMethodName, "socks4", ln.Addr())
Log("listening on %s", ln.Addr().String())
listeners = append(listeners, ln)
}
- PtCmethodsDone()
+ pt.CmethodsDone()
var numHandlers int = 0
diff --git a/websocket-transport/websocket-server.go b/websocket-transport/websocket-server.go
index 4c1dd4b..4362fd6 100644
--- a/websocket-transport/websocket-server.go
+++ b/websocket-transport/websocket-server.go
@@ -19,6 +19,8 @@ import (
"time"
)
+import "./pt"
+
const ptMethodName = "websocket"
const requestTimeout = 10 * time.Second
// "4/3+1" accounts for possible base64 encoding.
@@ -26,7 +28,7 @@ const maxMessageSize = 64*1024*4/3 + 1
var logFile = os.Stderr
-var ptInfo PtServerInfo
+var ptInfo pt.ServerInfo
// When a connection handler starts, +1 is written to this channel; when it
// ends, -1 is written.
@@ -171,7 +173,7 @@ func websocketHandler(ws *Websocket) {
handlerChan <- -1
}()
- s, err := PtConnectOr(&ptInfo, ws.Conn, ptMethodName)
+ s, err := pt.ConnectOr(&ptInfo, ws.Conn, ptMethodName)
if err != nil {
Log("Failed to connect to ORPort: " + err.Error())
return
@@ -220,7 +222,7 @@ func main() {
}
Log("starting")
- ptInfo = PtServerSetup([]string{ptMethodName})
+ ptInfo = pt.ServerSetup([]string{ptMethodName})
listeners := make([]*net.TCPListener, 0)
for _, bindAddr := range ptInfo.BindAddrs {
@@ -233,13 +235,13 @@ func main() {
ln, err := startListener(bindAddr.Addr)
if err != nil {
- PtSmethodError(bindAddr.MethodName, err.Error())
+ pt.SmethodError(bindAddr.MethodName, err.Error())
}
- PtSmethod(bindAddr.MethodName, ln.Addr())
+ pt.Smethod(bindAddr.MethodName, ln.Addr())
Log("listening on %s", ln.Addr().String())
listeners = append(listeners, ln)
}
- PtSmethodsDone()
+ pt.SmethodsDone()
var numHandlers int = 0
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