From 649bf79117e30895108b7782d62daafd07bc5e6e Mon Sep 17 00:00:00 2001 From: Niall Sheridan Date: Sun, 22 May 2016 01:23:33 +0100 Subject: Use govendor --- vendor/golang.org/x/crypto/ssh/tcpip.go | 407 ++++++++++++++++++++++++++++++++ 1 file changed, 407 insertions(+) create mode 100644 vendor/golang.org/x/crypto/ssh/tcpip.go (limited to 'vendor/golang.org/x/crypto/ssh/tcpip.go') diff --git a/vendor/golang.org/x/crypto/ssh/tcpip.go b/vendor/golang.org/x/crypto/ssh/tcpip.go new file mode 100644 index 0000000..6151241 --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/tcpip.go @@ -0,0 +1,407 @@ +// 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. +func (c *Client) Listen(n, addr string) (net.Listener, error) { + laddr, err := net.ResolveTCPAddr(n, addr) + if err != nil { + return nil, err + } + return c.ListenTCP(laddr) +} + +// 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 +} + +// 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) { + 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.TCPAddr + 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.TCPAddr // the raddr of the incoming connection +} + +func (l *forwardList) add(addr net.TCPAddr) chan forward { + l.Lock() + defer l.Unlock() + f := forwardEntry{ + addr, + 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 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 + } + + 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.TCPAddr) { + l.Lock() + defer l.Unlock() + for i, f := range l.entries { + if addr.IP.Equal(f.laddr.IP) && addr.Port == f.laddr.Port { + 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.TCPAddr, ch NewChannel) bool { + l.Lock() + defer l.Unlock() + for _, f := range l.entries { + if laddr.IP.Equal(f.laddr.IP) && laddr.Port == f.laddr.Port { + f.c <- forward{ch, &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 &tcpChanConn{ + 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) { + // 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 + } + // Use a zero address for local and remote address. + zeroAddr := &net.TCPAddr{ + IP: net.IPv4zero, + Port: 0, + } + ch, err := c.dial(net.IPv4zero.String(), 0, host, int(port)) + if err != nil { + return nil, err + } + return &tcpChanConn{ + Channel: ch, + laddr: zeroAddr, + raddr: zeroAddr, + }, nil +} + +// 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 &tcpChanConn{ + 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 +} + +// tcpChanConn fulfills the net.Conn interface without +// the tcpChan having to hold laddr or raddr directly. +type tcpChanConn struct { + Channel + laddr, raddr net.Addr +} + +// LocalAddr returns the local network address. +func (t *tcpChanConn) LocalAddr() net.Addr { + return t.laddr +} + +// RemoteAddr returns the remote network address. +func (t *tcpChanConn) RemoteAddr() net.Addr { + return t.raddr +} + +// SetDeadline sets the read and write deadlines associated +// with the connection. +func (t *tcpChanConn) 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 *tcpChanConn) SetReadDeadline(deadline time.Time) error { + 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 *tcpChanConn) SetWriteDeadline(deadline time.Time) error { + return errors.New("ssh: tcpChan: deadline not supported") +} -- cgit v1.2.3