February 2013 - tor-commits - lists.torproject.org

[flashproxy/master] Update pt.go server example.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit e5b1e1965431ec5bb75b2cfbabf7b834d1bccc49 Author: David Fifield <david(a)bamsoftware.com> Date: Sat Feb 2 20:29:39 2013 -0800 Update pt.go server example. --- websocket-transport/pt.go | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/websocket-transport/pt.go b/websocket-transport/pt.go index f39e177..61ec456 100644 --- a/websocket-transport/pt.go +++ b/websocket-transport/pt.go @@ -12,15 +12,23 @@ // // Sample server usage: // -// info := PtServerSetup([]string{"foo", "bar"}) +// var ptInfo PtServerInfo +// info = PtServerSetup([]string{"foo", "bar"}) // for _, bindAddr := range info.BindAddrs { // ln, err := startListener(bindAddr.Addr) // if err != nil { -// panic(err.Error()) +// 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

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[flashproxy/master] ChangeLog for websocket-server.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit bc2fe0520411ec589ca49bc5c3a1b17f79bf8138 Author: David Fifield <david(a)bamsoftware.com> Date: Sat Feb 2 20:10:52 2013 -0800 ChangeLog for websocket-server. --- ChangeLog | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/ChangeLog b/ChangeLog index f7be997..98835c1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +Changes in version 0.13 + o The new websocket-server program is the server transport plugin that + flash proxies talk to. It replaces the third-party websockify + program that was used formerly. It works as a managed proxy and + supports the extended ORPort protocol. Fixes bug 7620. + Changes in version 0.12 o Added a line of JavaScript that you can use to put a proxy badge on MediaWiki sites that allow custom JavaScript. Follow the

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[flashproxy/master] Make the message size limit 16384 bytes.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit 0eb274389f5967d2448c818a5f3942c2b1cc3d5f Author: David Fifield <david(a)bamsoftware.com> Date: Sat Feb 2 20:05:01 2013 -0800 Make the message size limit 16384 bytes. I forgot that in #8126 I saw messages of 8926 bytes, bigger than the 8192-byte limit I just pushed. --- doc/websocket-transport.txt | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/websocket-transport.txt b/doc/websocket-transport.txt index 9904929..a9d839f 100644 --- a/doc/websocket-transport.txt +++ b/doc/websocket-transport.txt @@ -180,8 +180,8 @@ Considerations specific to pluggable transports length of the next frame exceeds the limit, the endpoint MUST close the connection and SHOULD do so with a status code of 1009 (see RFC 6455 section 7.4.1). Endpoints MUST be capable of receiving messages - containing up to 8192 bytes of binary data; this may require - buffering up to 10923 bytes of UTF-8–encoded base64 text. + containing up to 16384 bytes of binary data; this may require + buffering up to 21848 bytes of UTF-8–encoded base64 text. Questions/extensions

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[flashproxy/master] Raise buffering limit from 1500 to 8192 in websocket-transport.txt.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit b94a7b111259245c87e91297b06d3ebb4f6afb3e Author: David Fifield <david(a)bamsoftware.com> Date: Sat Feb 2 20:01:08 2013 -0800 Raise buffering limit from 1500 to 8192 in websocket-transport.txt. --- doc/websocket-transport.txt | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/websocket-transport.txt b/doc/websocket-transport.txt index 94d4060..9904929 100644 --- a/doc/websocket-transport.txt +++ b/doc/websocket-transport.txt @@ -180,8 +180,8 @@ Considerations specific to pluggable transports length of the next frame exceeds the limit, the endpoint MUST close the connection and SHOULD do so with a status code of 1009 (see RFC 6455 section 7.4.1). Endpoints MUST be capable of receiving messages - containing up to 1500 octets of binary data; this may require - buffering up to 2026 bytes of UTF-8–encoded base64 text. + containing up to 8192 bytes of binary data; this may require + buffering up to 10923 bytes of UTF-8–encoded base64 text. Questions/extensions

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[flashproxy/master] Increase max WebSocket message size from 2500 to 16384 bytes.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit a91e00df6ada0793f652f52f0d3a49984b6b2d0b Author: David Fifield <david(a)bamsoftware.com> Date: Sat Feb 2 19:45:09 2013 -0800 Increase max WebSocket message size from 2500 to 16384 bytes. See #8126. The largest size I saw was 8926 bytes. flashproxy-client allows larger messages than this; it may not make sense for these values to be unequal. I want to be a bit more conservative with websocket-server because it will be managing many more simultaneous connections. --- websocket-transport/websocket-server.go | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/websocket-transport/websocket-server.go b/websocket-transport/websocket-server.go index 72d48b2..c269951 100644 --- a/websocket-transport/websocket-server.go +++ b/websocket-transport/websocket-server.go @@ -168,7 +168,7 @@ func startListener(addr *net.TCPAddr) (*net.TCPListener, error) { go func() { var config WebsocketConfig config.Subprotocols = []string{"base64"} - config.MaxMessageSize = 2500 + config.MaxMessageSize = 16 * 1024 http.Handle("/", config.Handler(websocketHandler)) err = http.Serve(ln, nil) if err != nil {

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[flashproxy/master] Add dummy reading of auth cookie file.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit 60a611d110481b237dc62516493bbccf1cb61389 Author: David Fifield <david(a)bamsoftware.com> Date: Mon Jan 28 22:26:23 2013 -0800 Add dummy reading of auth cookie file. --- websocket-transport/pt.go | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-) diff --git a/websocket-transport/pt.go b/websocket-transport/pt.go index ac5270e..d5435fa 100644 --- a/websocket-transport/pt.go +++ b/websocket-transport/pt.go @@ -259,12 +259,21 @@ func getServerBindAddrs(methodNames []string) []PtBindAddr { 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) { + cookie := make([]byte, 32) + + 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 @@ -302,5 +311,13 @@ func PtServerSetup(methodNames []string) PtServerInfo { } } + 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 }

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[flashproxy/master] Add URL to bug4773_rebase.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit 8ff34d18939f1a973339ee663a8a5b70b6340948 Author: David Fifield <david(a)bamsoftware.com> Date: Mon Jan 28 23:25:09 2013 -0800 Add URL to bug4773_rebase. --- README | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/README b/README index 1b5554e..fa2c94d 100644 --- a/README +++ b/README @@ -105,6 +105,8 @@ for the Go programming language ("apt-get install golang" on Debian). $ cd websocket-transport $ make # make install +You will need a version of Tor supporting the extended OR port protocol. + $ git clone https://git.torproject.org/user/asn/tor.git -b bug4773_rebase Add a line like the following to the relay's torrc. You can change the --port option; make sure that port is open in the firewall. ServerTransportPlugin websocket exec /usr/local/bin/websocket-server --port 9901

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[flashproxy/master] Add ExtORPort to relay config example.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit 4941dc278d9aa6294a15a18cb2e1afda98e8328c Author: David Fifield <david(a)bamsoftware.com> Date: Tue Jan 29 09:06:48 2013 -0800 Add ExtORPort to relay config example. --- README | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/README b/README index fa2c94d..5affeba 100644 --- a/README +++ b/README @@ -109,6 +109,7 @@ You will need a version of Tor supporting the extended OR port protocol. $ git clone https://git.torproject.org/user/asn/tor.git -b bug4773_rebase Add a line like the following to the relay's torrc. You can change the --port option; make sure that port is open in the firewall. + ExtORPort 5555 ServerTransportPlugin websocket exec /usr/local/bin/websocket-server --port 9901 == How to put a flash proxy badge on a web page

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[flashproxy/master] Set a socket deadline in PtConnectOr.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit f56178868ca38a5c75b697bb98855882197b2260 Author: David Fifield <david(a)bamsoftware.com> Date: Wed Jan 30 01:49:18 2013 -0800 Set a socket deadline in PtConnectOr. --- websocket-transport/pt.go | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/websocket-transport/pt.go b/websocket-transport/pt.go index bb7866a..2b4a759 100644 --- a/websocket-transport/pt.go +++ b/websocket-transport/pt.go @@ -37,6 +37,7 @@ import ( "net" "os" "strings" + "time" ) func getenv(key string) string { @@ -467,11 +468,13 @@ func PtConnectOr(info *PtServerInfo, conn net.Conn) (*net.TCPConn, error) { 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 } + s.SetDeadline(time.Time{}) return s, nil }

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[flashproxy/master] extended OR port authentication.
by dcf＠torproject.org 03 Feb '13

03 Feb '13

commit e45fc2c2a82135c0f588d4ace19a3a090dc91a41 Author: David Fifield <david(a)bamsoftware.com> Date: Tue Jan 29 14:51:26 2013 -0800 extended OR port authentication. --- websocket-transport/pt.go | 118 ++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 117 insertions(+), 1 deletions(-) diff --git a/websocket-transport/pt.go b/websocket-transport/pt.go index a7459a8..bb7866a 100644 --- a/websocket-transport/pt.go +++ b/websocket-transport/pt.go @@ -25,7 +25,12 @@ package main import ( + "bufio" "bytes" + "crypto/hmac" + "crypto/rand" + "crypto/sha256" + "crypto/subtle" "errors" "fmt" "io" @@ -352,10 +357,121 @@ func PtServerSetup(methodNames []string) PtServerInfo { 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 +} + // 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) (*net.TCPConn, error) { - return net.DialTCP("tcp", nil, ptInfo.OrAddr) + 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 + } + err = extOrPortAuthenticate(s, info) + if err != nil { + s.Close() + return nil, err + } + + return s, nil }

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