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author | Péter Szilágyi <peterke@gmail.com> | 2017-04-11 07:25:53 +0800 |
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committer | Felix Lange <fjl@users.noreply.github.com> | 2017-04-11 07:25:53 +0800 |
commit | 706a1e552c96bf75c60844c1dc28fc83778795fc (patch) | |
tree | babbc6193bbdbde23f063a26544c630434047793 /vendor/golang.org/x/crypto/ssh/client.go | |
parent | 18bbe124259a852b349e8238ffe394639e29d803 (diff) | |
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cmd/puppeth: your Ethereum private network manager (#13854)
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/client.go')
-rw-r--r-- | vendor/golang.org/x/crypto/ssh/client.go | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/client.go b/vendor/golang.org/x/crypto/ssh/client.go new file mode 100644 index 000000000..c97f2978e --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/client.go @@ -0,0 +1,211 @@ +// 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" + "net" + "sync" + "time" +) + +// Client implements a traditional SSH client that supports shells, +// subprocesses, port forwarding and tunneled dialing. +type Client struct { + Conn + + forwards forwardList // forwarded tcpip connections from the remote side + mu sync.Mutex + channelHandlers map[string]chan NewChannel +} + +// HandleChannelOpen returns a channel on which NewChannel requests +// for the given type are sent. If the type already is being handled, +// nil is returned. The channel is closed when the connection is closed. +func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel { + c.mu.Lock() + defer c.mu.Unlock() + if c.channelHandlers == nil { + // The SSH channel has been closed. + c := make(chan NewChannel) + close(c) + return c + } + + ch := c.channelHandlers[channelType] + if ch != nil { + return nil + } + + ch = make(chan NewChannel, chanSize) + c.channelHandlers[channelType] = ch + return ch +} + +// NewClient creates a Client on top of the given connection. +func NewClient(c Conn, chans <-chan NewChannel, reqs <-chan *Request) *Client { + conn := &Client{ + Conn: c, + channelHandlers: make(map[string]chan NewChannel, 1), + } + + go conn.handleGlobalRequests(reqs) + go conn.handleChannelOpens(chans) + go func() { + conn.Wait() + conn.forwards.closeAll() + }() + go conn.forwards.handleChannels(conn.HandleChannelOpen("forwarded-tcpip")) + return conn +} + +// NewClientConn establishes an authenticated SSH connection using c +// as the underlying transport. The Request and NewChannel channels +// must be serviced or the connection will hang. +func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan NewChannel, <-chan *Request, error) { + fullConf := *config + fullConf.SetDefaults() + conn := &connection{ + sshConn: sshConn{conn: c}, + } + + if err := conn.clientHandshake(addr, &fullConf); err != nil { + c.Close() + return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %v", err) + } + conn.mux = newMux(conn.transport) + return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil +} + +// clientHandshake performs the client side key exchange. See RFC 4253 Section +// 7. +func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) error { + if config.ClientVersion != "" { + c.clientVersion = []byte(config.ClientVersion) + } else { + c.clientVersion = []byte(packageVersion) + } + var err error + c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion) + if err != nil { + return err + } + + c.transport = newClientTransport( + newTransport(c.sshConn.conn, config.Rand, true /* is client */), + c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr()) + if err := c.transport.waitSession(); err != nil { + return err + } + + c.sessionID = c.transport.getSessionID() + return c.clientAuthenticate(config) +} + +// verifyHostKeySignature verifies the host key obtained in the key +// exchange. +func verifyHostKeySignature(hostKey PublicKey, result *kexResult) error { + sig, rest, ok := parseSignatureBody(result.Signature) + if len(rest) > 0 || !ok { + return errors.New("ssh: signature parse error") + } + + return hostKey.Verify(result.H, sig) +} + +// NewSession opens a new Session for this client. (A session is a remote +// execution of a program.) +func (c *Client) NewSession() (*Session, error) { + ch, in, err := c.OpenChannel("session", nil) + if err != nil { + return nil, err + } + return newSession(ch, in) +} + +func (c *Client) handleGlobalRequests(incoming <-chan *Request) { + for r := range incoming { + // This handles keepalive messages and matches + // the behaviour of OpenSSH. + r.Reply(false, nil) + } +} + +// handleChannelOpens channel open messages from the remote side. +func (c *Client) handleChannelOpens(in <-chan NewChannel) { + for ch := range in { + c.mu.Lock() + handler := c.channelHandlers[ch.ChannelType()] + c.mu.Unlock() + + if handler != nil { + handler <- ch + } else { + ch.Reject(UnknownChannelType, fmt.Sprintf("unknown channel type: %v", ch.ChannelType())) + } + } + + c.mu.Lock() + for _, ch := range c.channelHandlers { + close(ch) + } + c.channelHandlers = nil + c.mu.Unlock() +} + +// Dial starts a client connection to the given SSH server. It is a +// convenience function that connects to the given network address, +// initiates the SSH handshake, and then sets up a Client. For access +// to incoming channels and requests, use net.Dial with NewClientConn +// instead. +func Dial(network, addr string, config *ClientConfig) (*Client, error) { + conn, err := net.DialTimeout(network, addr, config.Timeout) + if err != nil { + return nil, err + } + c, chans, reqs, err := NewClientConn(conn, addr, config) + if err != nil { + return nil, err + } + return NewClient(c, chans, reqs), nil +} + +// A ClientConfig structure is used to configure a Client. It must not be +// modified after having been passed to an SSH function. +type ClientConfig struct { + // Config contains configuration that is shared between clients and + // servers. + Config + + // User contains the username to authenticate as. + User string + + // Auth contains possible authentication methods to use with the + // server. Only the first instance of a particular RFC 4252 method will + // be used during authentication. + Auth []AuthMethod + + // HostKeyCallback, if not nil, is called during the cryptographic + // handshake to validate the server's host key. A nil HostKeyCallback + // implies that all host keys are accepted. + HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error + + // ClientVersion contains the version identification string that will + // be used for the connection. If empty, a reasonable default is used. + ClientVersion string + + // HostKeyAlgorithms lists the key types that the client will + // accept from the server as host key, in order of + // preference. If empty, a reasonable default is used. Any + // string returned from PublicKey.Type method may be used, or + // any of the CertAlgoXxxx and KeyAlgoXxxx constants. + HostKeyAlgorithms []string + + // Timeout is the maximum amount of time for the TCP connection to establish. + // + // A Timeout of zero means no timeout. + Timeout time.Duration +} |