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Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/channel.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/channel.go | 633 |
1 files changed, 0 insertions, 633 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/channel.go b/vendor/golang.org/x/crypto/ssh/channel.go deleted file mode 100644 index c0834c0..0000000 --- a/vendor/golang.org/x/crypto/ssh/channel.go +++ /dev/null @@ -1,633 +0,0 @@ -// 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 -} |