ceph-csi/vendor/golang.org/x/crypto/ssh/mux.go
Niels de Vos 91774fc936 rebase: vendor dependencies for Vault API
Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.

By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.

Signed-off-by: Niels de Vos <ndevos@redhat.com>
2020-11-29 04:03:59 +00:00

352 lines
7.7 KiB
Go

// Copyright 2013 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"
"fmt"
"io"
"log"
"sync"
"sync/atomic"
)
// debugMux, if set, causes messages in the connection protocol to be
// logged.
const debugMux = false
// chanList is a thread safe channel list.
type chanList struct {
// protects concurrent access to chans
sync.Mutex
// chans are indexed by the local id of the channel, which the
// other side should send in the PeersId field.
chans []*channel
// This is a debugging aid: it offsets all IDs by this
// amount. This helps distinguish otherwise identical
// server/client muxes
offset uint32
}
// Assigns a channel ID to the given channel.
func (c *chanList) add(ch *channel) uint32 {
c.Lock()
defer c.Unlock()
for i := range c.chans {
if c.chans[i] == nil {
c.chans[i] = ch
return uint32(i) + c.offset
}
}
c.chans = append(c.chans, ch)
return uint32(len(c.chans)-1) + c.offset
}
// getChan returns the channel for the given ID.
func (c *chanList) getChan(id uint32) *channel {
id -= c.offset
c.Lock()
defer c.Unlock()
if id < uint32(len(c.chans)) {
return c.chans[id]
}
return nil
}
func (c *chanList) remove(id uint32) {
id -= c.offset
c.Lock()
if id < uint32(len(c.chans)) {
c.chans[id] = nil
}
c.Unlock()
}
// dropAll forgets all channels it knows, returning them in a slice.
func (c *chanList) dropAll() []*channel {
c.Lock()
defer c.Unlock()
var r []*channel
for _, ch := range c.chans {
if ch == nil {
continue
}
r = append(r, ch)
}
c.chans = nil
return r
}
// mux represents the state for the SSH connection protocol, which
// multiplexes many channels onto a single packet transport.
type mux struct {
conn packetConn
chanList chanList
incomingChannels chan NewChannel
globalSentMu sync.Mutex
globalResponses chan interface{}
incomingRequests chan *Request
errCond *sync.Cond
err error
}
// When debugging, each new chanList instantiation has a different
// offset.
var globalOff uint32
func (m *mux) Wait() error {
m.errCond.L.Lock()
defer m.errCond.L.Unlock()
for m.err == nil {
m.errCond.Wait()
}
return m.err
}
// newMux returns a mux that runs over the given connection.
func newMux(p packetConn) *mux {
m := &mux{
conn: p,
incomingChannels: make(chan NewChannel, chanSize),
globalResponses: make(chan interface{}, 1),
incomingRequests: make(chan *Request, chanSize),
errCond: newCond(),
}
if debugMux {
m.chanList.offset = atomic.AddUint32(&globalOff, 1)
}
go m.loop()
return m
}
func (m *mux) sendMessage(msg interface{}) error {
p := Marshal(msg)
if debugMux {
log.Printf("send global(%d): %#v", m.chanList.offset, msg)
}
return m.conn.writePacket(p)
}
func (m *mux) SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) {
if wantReply {
m.globalSentMu.Lock()
defer m.globalSentMu.Unlock()
}
if err := m.sendMessage(globalRequestMsg{
Type: name,
WantReply: wantReply,
Data: payload,
}); err != nil {
return false, nil, err
}
if !wantReply {
return false, nil, nil
}
msg, ok := <-m.globalResponses
if !ok {
return false, nil, io.EOF
}
switch msg := msg.(type) {
case *globalRequestFailureMsg:
return false, msg.Data, nil
case *globalRequestSuccessMsg:
return true, msg.Data, nil
default:
return false, nil, fmt.Errorf("ssh: unexpected response to request: %#v", msg)
}
}
// ackRequest must be called after processing a global request that
// has WantReply set.
func (m *mux) ackRequest(ok bool, data []byte) error {
if ok {
return m.sendMessage(globalRequestSuccessMsg{Data: data})
}
return m.sendMessage(globalRequestFailureMsg{Data: data})
}
func (m *mux) Close() error {
return m.conn.Close()
}
// loop runs the connection machine. It will process packets until an
// error is encountered. To synchronize on loop exit, use mux.Wait.
func (m *mux) loop() {
var err error
for err == nil {
err = m.onePacket()
}
for _, ch := range m.chanList.dropAll() {
ch.close()
}
close(m.incomingChannels)
close(m.incomingRequests)
close(m.globalResponses)
m.conn.Close()
m.errCond.L.Lock()
m.err = err
m.errCond.Broadcast()
m.errCond.L.Unlock()
if debugMux {
log.Println("loop exit", err)
}
}
// onePacket reads and processes one packet.
func (m *mux) onePacket() error {
packet, err := m.conn.readPacket()
if err != nil {
return err
}
if debugMux {
if packet[0] == msgChannelData || packet[0] == msgChannelExtendedData {
log.Printf("decoding(%d): data packet - %d bytes", m.chanList.offset, len(packet))
} else {
p, _ := decode(packet)
log.Printf("decoding(%d): %d %#v - %d bytes", m.chanList.offset, packet[0], p, len(packet))
}
}
switch packet[0] {
case msgChannelOpen:
return m.handleChannelOpen(packet)
case msgGlobalRequest, msgRequestSuccess, msgRequestFailure:
return m.handleGlobalPacket(packet)
}
// assume a channel packet.
if len(packet) < 5 {
return parseError(packet[0])
}
id := binary.BigEndian.Uint32(packet[1:])
ch := m.chanList.getChan(id)
if ch == nil {
return m.handleUnknownChannelPacket(id, packet)
}
return ch.handlePacket(packet)
}
func (m *mux) handleGlobalPacket(packet []byte) error {
msg, err := decode(packet)
if err != nil {
return err
}
switch msg := msg.(type) {
case *globalRequestMsg:
m.incomingRequests <- &Request{
Type: msg.Type,
WantReply: msg.WantReply,
Payload: msg.Data,
mux: m,
}
case *globalRequestSuccessMsg, *globalRequestFailureMsg:
m.globalResponses <- msg
default:
panic(fmt.Sprintf("not a global message %#v", msg))
}
return nil
}
// handleChannelOpen schedules a channel to be Accept()ed.
func (m *mux) handleChannelOpen(packet []byte) error {
var msg channelOpenMsg
if err := Unmarshal(packet, &msg); err != nil {
return err
}
if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
failMsg := channelOpenFailureMsg{
PeersID: msg.PeersID,
Reason: ConnectionFailed,
Message: "invalid request",
Language: "en_US.UTF-8",
}
return m.sendMessage(failMsg)
}
c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData)
c.remoteId = msg.PeersID
c.maxRemotePayload = msg.MaxPacketSize
c.remoteWin.add(msg.PeersWindow)
m.incomingChannels <- c
return nil
}
func (m *mux) OpenChannel(chanType string, extra []byte) (Channel, <-chan *Request, error) {
ch, err := m.openChannel(chanType, extra)
if err != nil {
return nil, nil, err
}
return ch, ch.incomingRequests, nil
}
func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) {
ch := m.newChannel(chanType, channelOutbound, extra)
ch.maxIncomingPayload = channelMaxPacket
open := channelOpenMsg{
ChanType: chanType,
PeersWindow: ch.myWindow,
MaxPacketSize: ch.maxIncomingPayload,
TypeSpecificData: extra,
PeersID: ch.localId,
}
if err := m.sendMessage(open); err != nil {
return nil, err
}
switch msg := (<-ch.msg).(type) {
case *channelOpenConfirmMsg:
return ch, nil
case *channelOpenFailureMsg:
return nil, &OpenChannelError{msg.Reason, msg.Message}
default:
return nil, fmt.Errorf("ssh: unexpected packet in response to channel open: %T", msg)
}
}
func (m *mux) handleUnknownChannelPacket(id uint32, packet []byte) error {
msg, err := decode(packet)
if err != nil {
return err
}
switch msg := msg.(type) {
// RFC 4254 section 5.4 says unrecognized channel requests should
// receive a failure response.
case *channelRequestMsg:
if msg.WantReply {
return m.sendMessage(channelRequestFailureMsg{
PeersID: msg.PeersID,
})
}
return nil
default:
return fmt.Errorf("ssh: invalid channel %d", id)
}
}