ssh1

package module
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 Go to latest Published: Jun 28, 2022 License: BSD-3-Clause Imports: 25 Imported by: 0

README

go-ssh1

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RFC Draft for v1.3

RFC Draft for v1.5

Documentation

Overview

Package ssh1 implements an SSHv1 client.

SSH is a transport security protocol, an authentication protocol and a family of application protocols. The most typical application level protocol is a remote shell and this is specifically implemented. However, the multiplexed nature of SSH is exposed to users that wish to support others.

References: 

[RFC Draft for v1.3]: https://tools.ietf.org/html/draft-ylonen-ssh-protocol-00
[RFC Draft for v1.5]: http://www.snailbook.com/docs/protocol-1.5.txt

Index

Constants

View Source 
const (
	// SSH_CIPHER_NONE is no encryption.
	SSH_CIPHER_NONE = iota
	// SSH_CIPHER_IDEA is IDEA in CFB mode.
	SSH_CIPHER_IDEA
	// SSH_CIPHER_DES is DES in CBC mode.
	SSH_CIPHER_DES
	// SSH_CIPHER_3DES is three independent DES-CBC ciphers used in EDE mode.
	SSH_CIPHER_3DES

	// SSH_CIPHER_RC4 is RC4.
	SSH_CIPHER_RC4
	// SSH_CIPHER_BLOWFISH is Blowfish. It's not specified in RFC but used by OpenSSH.
	SSH_CIPHER_BLOWFISH
)
View Source 
const (
	// SSH_AUTH_RHOSTS is auth using .rhosts file
	SSH_AUTH_RHOSTS = iota + 1
	// SSH_AUTH_RSA is RSA auth
	SSH_AUTH_RSA
	// SSH_AUTH_PASSWORD is auth using password
	SSH_AUTH_PASSWORD
	// SSH_AUTH_RHOSTS_RSA is auth using .rhosts file with RSA
	SSH_AUTH_RHOSTS_RSA
	SSH_AUTH_TIS
	SSH_AUTH_KERBEROS
)
View Source 
const (
	VINTR         = 1
	VQUIT         = 2
	VERASE        = 3
	VKILL         = 4
	VEOF          = 5
	VEOL          = 6
	VEOL2         = 7
	VSTART        = 8
	VSTOP         = 9
	VSUSP         = 10
	VDSUSP        = 11
	VREPRINT      = 12
	VWERASE       = 13
	VLNEXT        = 14
	VFLUSH        = 15
	VSWTCH        = 16
	VSTATUS       = 17
	VDISCARD      = 18
	IGNPAR        = 30
	PARMRK        = 31
	INPCK         = 32
	ISTRIP        = 33
	INLCR         = 34
	IGNCR         = 35
	ICRNL         = 36
	IUCLC         = 37
	IXON          = 38
	IXANY         = 39
	IXOFF         = 40
	IMAXBEL       = 41
	ISIG          = 50
	ICANON        = 51
	XCASE         = 52
	ECHO          = 53
	ECHOE         = 54
	ECHOK         = 55
	ECHONL        = 56
	NOFLSH        = 57
	TOSTOP        = 58
	IEXTEN        = 59
	ECHOCTL       = 60
	ECHOKE        = 61
	PENDIN        = 62
	OPOST         = 70
	OLCUC         = 71
	ONLCR         = 72
	OCRNL         = 73
	ONOCR         = 74
	ONLRET        = 75
	CS7           = 90
	CS8           = 91
	PARENB        = 92
	PARODD        = 93
	TTY_OP_ISPEED = 192
	TTY_OP_OSPEED = 193
)

POSIX terminal mode flags as listed in RFC, section Encoding of Terminal Modes.

Variables

This section is empty.

Functions

func Marshal 

func Marshal(msg interface{}) (byte, []byte)

Marshal serializes the message in msg to SSH wire format. The msg argument should be a struct or pointer to struct. If the first member has the "ssh1type" tag set to a number in decimal, that number is prepended to the result. If the last of member has the "ssh" tag set to "rest", its contents are appended to the output.

func NewClientConn 

func NewClientConn(c net.Conn, addr string, config *Config) (*transport, *sshConn, error)

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 Unmarshal 

func Unmarshal(packetType byte, data []byte, out interface{}) error

Unmarshal parses data in SSH wire format into a structure. The out argument should be a pointer to struct. If the first member of the struct has the "ssh1type" tag set to a '|'-separated set of numbers in decimal, the packet must start with one of those numbers. In case of error, Unmarshal returns a ParseError or UnexpectedMessageError.

Types

type AuthMethod 

type AuthMethod interface {
	// contains filtered or unexported methods
}

An AuthMethod represents an instance of an RFC 4252 authentication method.

func Password 

func Password(secret string) AuthMethod

Password returns an AuthMethod using the given password.

func PasswordCallback 

func PasswordCallback(prompt func() (secret string, err error)) AuthMethod

PasswordCallback returns an AuthMethod that uses a callback for fetching a password.

type BannerCallback 

type BannerCallback func(message string) error

BannerCallback is the function type used for treat the banner sent by the server. A BannerCallback receives the message sent by the remote server.

func BannerDisplayStderr 

func BannerDisplayStderr() BannerCallback

BannerDisplayStderr returns a function that can be used for ClientConfig.BannerCallback to display banners on os.Stderr.

type Channel 

type Channel interface {
	// Read reads up to len(data) bytes from the channel.
	Read(data []byte) (int, error)

	// ReadStatus reads up to len(data) bytes from the channel.
	ReadStatus(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

	// 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

	SendRequest(name string, wantReply bool, payload []byte) (bool, error)
}

A Channel is an ordered, reliable, flow-controlled, duplex stream that is multiplexed over an SSH connection.

type Client 

type Client struct {
	// contains filtered or unexported fields
}

Client implements a traditional SSH client that supports shells, subprocesses, TCP port/streamlocal forwarding and tunneled dialing.

func Dial 

func Dial(addr string, config *Config) (*Client, error)

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 (*Client) Close 

func (c *Client) Close() error

func (*Client) NewSession 

func (c *Client) NewSession() (*Session, error)

NewSession opens a new Session for this client. (A session is a remote execution of a program.)

type Config 

type Config struct {
	// Rand provides the source of entropy for cryptographic
	// primitives. If Rand is nil, the cryptographic random reader
	// in package crypto/rand will be used.
	Rand io.Reader

	// The ciphers order for cipher selection. If unspecified then a sensible
	// default is used.
	CiphersOrder []int

	// User contains the username to authenticate as.
	User string

	// The auth methods. Would be tried in specified order.
	AuthMethods []AuthMethod

	// HostKeyCallback is called during the cryptographic
	// handshake to validate the server's host key. The client
	// configuration must supply this callback for the connection
	// to succeed. The functions InsecureIgnoreHostKey or
	// FixedHostKey can be used for simplistic host key checks.
	HostKeyCallback HostKeyCallback

	// BannerCallback is called during the SSH dance to display a custom
	// server's message. The client configuration can supply this callback to
	// handle it as wished. The function BannerDisplayStderr can be used for
	// simplistic display on Stderr.
	BannerCallback BannerCallback

	// ClientVersion contains the version identification string that will
	// be used for the connection. If empty, a reasonable default is used.
	Version string

	// Timeout is the maximum amount of time for the TCP connection to establish.
	//
	// A Timeout of zero means no timeout.
	Timeout time.Duration
}

Config contains configuration data common to both ServerConfig and ClientConfig.

func (*Config) SetDefaults 

func (c *Config) SetDefaults()

SetDefaults sets sensible values for unset fields in config. This is exported for testing: Configs passed to SSH functions are copied and have default values set automatically.

type ExitError 

type ExitError struct {
	Waitmsg
}

An ExitError reports unsuccessful completion of a remote command.

func (*ExitError) Error 

func (e *ExitError) Error() string

type HostKeyCallback 

type HostKeyCallback func(hostname string, remote net.Addr, key *rsa.PublicKey) error

HostKeyCallback is the function type used for verifying server keys. A HostKeyCallback must return nil if the host key is OK, or an error to reject it. It receives the hostname as passed to Dial or NewClientConn. The remote address is the RemoteAddr of the net.Conn underlying the SSH connection.

func InsecureIgnoreHostKey 

func InsecureIgnoreHostKey() HostKeyCallback

InsecureIgnoreHostKey returns a function that can be used for ClientConfig.HostKeyCallback to accept any host key. It should not be used for production code.

type RejectionReason 

type RejectionReason uint32

RejectionReason is an enumeration used when rejecting channel creation requests. See RFC 4254, section 5.1. 

const (
	Prohibited RejectionReason = iota + 1
	ConnectionFailed
	UnknownChannelType
	ResourceShortage
)

func (RejectionReason) String 

func (r RejectionReason) String() string

String converts the rejection reason to human-readable form.

type Session 

type Session struct {

	// Stdin specifies the remote process's standard input.
	// If Stdin is nil, the remote process reads from an empty
	// bytes.Buffer.
	Stdin io.Reader

	// Stdout and Stderr specify the remote process's standard
	// output and error.
	//
	// If either is nil, Run connects the corresponding file
	// descriptor to an instance of io.Discard. There is a
	// fixed amount of buffering that is shared for the two streams.
	// If either blocks it may eventually cause the remote
	// command to block.
	Stdout io.Writer
	Stderr io.Writer
	// contains filtered or unexported fields
}

A Session represents a connection to a remote command or shell.

func (*Session) Close 

func (s *Session) Close() error

func (*Session) RequestPty 

func (s *Session) RequestPty(term string, h, w int, termmodes TerminalModes) error

RequestPty requests the association of a pty with the session on the remote host.

func (*Session) Run 

func (s *Session) Run(cmd string) error

Run runs cmd on the remote host. Typically, the remote server passes cmd to the shell for interpretation. A Session only accepts one call to Run, Start, Shell, Output, or CombinedOutput.

The returned error is nil if the command runs, has no problems copying stdin, stdout, and stderr, and exits with a zero exit status.

If the remote server does not send an exit status, an error of type *ExitMissingError is returned. If the command completes unsuccessfully or is interrupted by a signal, the error is of type *ExitError. Other error types may be returned for I/O problems.

func (*Session) SendRequest 

func (s *Session) SendRequest(name string, wantReply bool, payload []byte) (bool, error)

SendRequest sends an out-of-band channel request on the SSH channel underlying the session.

func (*Session) Shell 

func (s *Session) Shell() error

Shell starts a shell on the remote host. A Session only accepts one call to Run, Start, Shell.

func (*Session) Start 

func (s *Session) Start(cmd string) error

Start runs cmd on the remote host. Typically, the remote server passes cmd to the shell for interpretation. A Session only accepts one call to Run, Start or Shell.

func (*Session) StderrPipe 

func (s *Session) StderrPipe() (io.Reader, error)

StderrPipe returns a pipe that will be connected to the remote command's standard error when the command starts. There is a fixed amount of buffering that is shared between stdout and stderr streams. If the StderrPipe reader is not serviced fast enough it may eventually cause the remote command to block.

func (*Session) StdinPipe 

func (s *Session) StdinPipe() (io.WriteCloser, error)

StdinPipe returns a pipe that will be connected to the remote command's standard input when the command starts.

func (*Session) StdoutPipe 

func (s *Session) StdoutPipe() (io.Reader, error)

StdoutPipe returns a pipe that will be connected to the remote command's standard output when the command starts. There is a fixed amount of buffering that is shared between stdout and stderr streams. If the StdoutPipe reader is not serviced fast enough it may eventually cause the remote command to block.

func (*Session) Wait 

func (s *Session) Wait() error

Wait waits for the remote command to exit.

The returned error is nil if the command runs, has no problems copying stdin, stdout, and stderr, and exits with a zero exit status.

If the remote server does not send an exit status, an error of type *ExitMissingError is returned. If the command completes unsuccessfully or is interrupted by a signal, the error is of type *ExitError. Other error types may be returned for I/O problems.

func (*Session) WindowChange 

func (s *Session) WindowChange(h, w int) error

WindowChange informs the remote host about a terminal window dimension change to h rows and w columns.

type Signal 

type Signal string
const (
	SIGABRT Signal = "ABRT"
	SIGALRM Signal = "ALRM"
	SIGFPE  Signal = "FPE"
	SIGHUP  Signal = "HUP"
	SIGILL  Signal = "ILL"
	SIGINT  Signal = "INT"
	SIGKILL Signal = "KILL"
	SIGPIPE Signal = "PIPE"
	SIGQUIT Signal = "QUIT"
	SIGSEGV Signal = "SEGV"
	SIGTERM Signal = "TERM"
	SIGUSR1 Signal = "USR1"
	SIGUSR2 Signal = "USR2"
)

POSIX signals as listed in RFC 4254 Section 6.10.

type TerminalModes 

type TerminalModes map[uint8]uint32

type Waitmsg 

type Waitmsg struct {
	// contains filtered or unexported fields
}

Waitmsg stores the information about an exited remote command as reported by Wait.

func (Waitmsg) ExitStatus 

func (w Waitmsg) ExitStatus() int

ExitStatus returns the exit status of the remote command.

func (Waitmsg) Lang 

func (w Waitmsg) Lang() string

Lang returns the language tag. See RFC 3066

func (Waitmsg) Msg 

func (w Waitmsg) Msg() string

Msg returns the exit message given by the remote command

func (Waitmsg) Signal 

func (w Waitmsg) Signal() string

Signal returns the exit signal of the remote command if it was terminated violently.

func (Waitmsg) String 

func (w Waitmsg) String() string

Source Files

View all Source files

Directories

Path Synopsis
examples
simple
terminal

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