def send(self, s): """ Send data to the channel. Returns the number of bytes sent, or 0 if the channel stream is closed. Applications are responsible for checking that all data has been sent: if only some of the data was transmitted, the application needs to attempt delivery of the remaining data. @param s: data to send @type s: str @return: number of bytes actually sent @rtype: int @raise socket.timeout: if no data could be sent before the timeout set by L{settimeout}. """ size = len(s) self.lock.acquire() try: size = self._wait_for_send_window(size) if size == 0: # eof or similar return 0 m = Message() m.add_byte(chr(MSG_CHANNEL_DATA)) m.add_int(self.remote_chanid) m.add_string(s[:size]) finally: self.lock.release() # Note: We release self.lock before calling _send_user_message. # Otherwise, we can deadlock during re-keying. self.transport._send_user_message(m) return size
def recv_stderr(self, nbytes): """ Receive data from the channel's stderr stream. Only channels using L{exec_command} or L{invoke_shell} without a pty will ever have data on the stderr stream. The return value is a string representing the data received. The maximum amount of data to be received at once is specified by C{nbytes}. If a string of length zero is returned, the channel stream has closed. @param nbytes: maximum number of bytes to read. @type nbytes: int @return: data. @rtype: str @raise socket.timeout: if no data is ready before the timeout set by L{settimeout}. @since: 1.1 """ try: out = self.in_stderr_buffer.read(nbytes, self.timeout) except PipeTimeout as e: raise socket.timeout() ack = self._check_add_window(len(out)) # no need to hold the channel lock when sending this if ack > 0: m = Message() m.add_byte(chr(MSG_CHANNEL_WINDOW_ADJUST)) m.add_int(self.remote_chanid) m.add_int(ack) self.transport._send_user_message(m) return out
def invoke_subsystem(self, subsystem): """ Request a subsystem on the server (for example, C{sftp}). If the server allows it, the channel will then be directly connected to the requested subsystem. When the subsystem finishes, the channel will be closed and can't be reused. @param subsystem: name of the subsystem being requested. @type subsystem: str @raise SSHException: if the request was rejected or the channel was closed """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('subsystem') m.add_boolean(True) m.add_string(subsystem) self._event_pending() self.transport._send_user_message(m) self._wait_for_event()
def exec_command(self, command): """ Execute a command on the server. If the server allows it, the channel will then be directly connected to the stdin, stdout, and stderr of the command being executed. When the command finishes executing, the channel will be closed and can't be reused. You must open a new channel if you wish to execute another command. @param command: a shell command to execute. @type command: str @raise SSHException: if the request was rejected or the channel was closed """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('exec') m.add_boolean(True) m.add_string(command) self._event_pending() self.transport._send_user_message(m) self._wait_for_event()
def invoke_shell(self): """ Request an interactive shell session on this channel. If the server allows it, the channel will then be directly connected to the stdin, stdout, and stderr of the shell. Normally you would call L{get_pty} before this, in which case the shell will operate through the pty, and the channel will be connected to the stdin and stdout of the pty. When the shell exits, the channel will be closed and can't be reused. You must open a new channel if you wish to open another shell. @raise SSHException: if the request was rejected or the channel was closed """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('shell') m.add_boolean(1) self._event_pending() self.transport._send_user_message(m) self._wait_for_event()
def _disconnect_service_not_available(self): m = Message() m.add_byte(chr(MSG_DISCONNECT)) m.add_int(DISCONNECT_SERVICE_NOT_AVAILABLE) m.add_string('Service not available') m.add_string('en') self.transport._send_message(m) self.transport.close()
def _disconnect_no_more_auth(self): m = Message() m.add_byte(chr(MSG_DISCONNECT)) m.add_int(DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE) m.add_string('No more auth methods available') m.add_string('en') self.transport._send_message(m) self.transport.close()
def _send_eof(self): # you are holding the lock. if self.eof_sent: return None m = Message() m.add_byte(chr(MSG_CHANNEL_EOF)) m.add_int(self.remote_chanid) self.eof_sent = True self._log(DEBUG, 'EOF sent (%s)', self._name) return m
def sign_ssh_data(self, rng, data): msg = Message() msg.add_byte(chr(SSH2_AGENTC_SIGN_REQUEST)) msg.add_string(self.blob) msg.add_string(data) msg.add_int(0) ptype, result = self.agent._send_message(msg) if ptype != SSH2_AGENT_SIGN_RESPONSE: raise SSHException('key cannot be used for signing') return result.get_string()
def _negotiate_keys_wrapper(self, m): if self.local_kex_init is None: # Remote side sent KEXINIT # Simulate in-transit MSG_CHANNEL_WINDOW_ADJUST by sending it # before responding to the incoming MSG_KEXINIT. m2 = Message() m2.add_byte(chr(MSG_CHANNEL_WINDOW_ADJUST)) m2.add_int(chan.remote_chanid) m2.add_int(1) # bytes to add self._send_message(m2) return _negotiate_keys(self, m)
def _interactive_query(self, q): # make interactive query instead of response m = Message() m.add_byte(chr(MSG_USERAUTH_INFO_REQUEST)) m.add_string(q.name) m.add_string(q.instructions) m.add_string('') m.add_int(len(q.prompts)) for p in q.prompts: m.add_string(p[0]) m.add_boolean(p[1]) self.transport._send_message(m)
def _close_internal(self): # you are holding the lock. if not self.active or self.closed: return None, None m1 = self._send_eof() m2 = Message() m2.add_byte(chr(MSG_CHANNEL_CLOSE)) m2.add_int(self.remote_chanid) self._set_closed() # can't unlink from the Transport yet -- the remote side may still # try to send meta-data (exit-status, etc) return m1, m2
def resize_pty(self, width=80, height=24): """ Resize the pseudo-terminal. This can be used to change the width and height of the terminal emulation created in a previous L{get_pty} call. @param width: new width (in characters) of the terminal screen @type width: int @param height: new height (in characters) of the terminal screen @type height: int @raise SSHException: if the request was rejected or the channel was closed """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('window-change') m.add_boolean(True) m.add_int(width) m.add_int(height) m.add_int(0).add_int(0) self._event_pending() self.transport._send_user_message(m) self._wait_for_event()
def get_pty(self, term='vt100', width=80, height=24): """ Request a pseudo-terminal from the server. This is usually used right after creating a client channel, to ask the server to provide some basic terminal semantics for a shell invoked with L{invoke_shell}. It isn't necessary (or desirable) to call this method if you're going to exectue a single command with L{exec_command}. @param term: the terminal type to emulate (for example, C{'vt100'}) @type term: str @param width: width (in characters) of the terminal screen @type width: int @param height: height (in characters) of the terminal screen @type height: int @raise SSHException: if the request was rejected or the channel was closed """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('pty-req') m.add_boolean(True) m.add_string(term) m.add_int(width) m.add_int(height) # pixel height, width (usually useless) m.add_int(0).add_int(0) m.add_string('') self._event_pending() self.transport._send_user_message(m) self._wait_for_event()
def _send_server_version(self): # winscp will freak out if the server sends version info before the # client finishes sending INIT. t, data = self._read_packet() if t != CMD_INIT: raise SFTPError('Incompatible sftp protocol') version = struct.unpack('>I', data[:4])[0] # advertise that we support "check-file" extension_pairs = [ 'check-file', 'md5,sha1' ] msg = Message() msg.add_int(_VERSION) msg.add(*extension_pairs) self._send_packet(CMD_VERSION, str(msg)) return version
def _send_server_version(self): # winscp will freak out if the server sends version info before the # client finishes sending INIT. t, data = self._read_packet() if t != CMD_INIT: raise SFTPError('Incompatible sftp protocol') version = struct.unpack('>I', data[:4])[0] # advertise that we support "check-file" extension_pairs = ['check-file', 'md5,sha1'] msg = Message() msg.add_int(_VERSION) msg.add(*extension_pairs) self._send_packet(CMD_VERSION, str(msg)) return version
def _parse_userauth_info_request(self, m): if self.auth_method != 'keyboard-interactive': raise SSHException('Illegal info request from server') title = m.get_string() instructions = m.get_string() m.get_string() # lang prompts = m.get_int() prompt_list = [] for i in range(prompts): prompt_list.append((m.get_string(), m.get_boolean())) response_list = self.interactive_handler(title, instructions, prompt_list) m = Message() m.add_byte(chr(MSG_USERAUTH_INFO_RESPONSE)) m.add_int(len(response_list)) for r in response_list: m.add_string(r) self.transport._send_message(m)
def send_exit_status(self, status): """ Send the exit status of an executed command to the client. (This really only makes sense in server mode.) Many clients expect to get some sort of status code back from an executed command after it completes. @param status: the exit code of the process @type status: int @since: 1.2 """ # in many cases, the channel will not still be open here. # that's fine. m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('exit-status') m.add_boolean(False) m.add_int(status) self.transport._send_user_message(m)
def _parse_kexdh_gex_init(self, m): self.e = m.get_mpint() if (self.e < 1) or (self.e > self.p - 1): raise SSHException('Client kex "e" is out of range') self._generate_x() self.f = pow(self.g, self.x, self.p) K = pow(self.e, self.x, self.p) key = str(self.transport.get_server_key()) # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K) hm = Message() hm.add(self.transport.remote_version, self.transport.local_version, self.transport.remote_kex_init, self.transport.local_kex_init, key) if not self.old_style: hm.add_int(self.min_bits) hm.add_int(self.preferred_bits) if not self.old_style: hm.add_int(self.max_bits) hm.add_mpint(self.p) hm.add_mpint(self.g) hm.add_mpint(self.e) hm.add_mpint(self.f) hm.add_mpint(K) H = SHA.new(str(hm)).digest() self.transport._set_K_H(K, H) # sign it sig = self.transport.get_server_key().sign_ssh_data(self.transport.rng, H) # send reply m = Message() m.add_byte(chr(_MSG_KEXDH_GEX_REPLY)) m.add_string(key) m.add_mpint(self.f) m.add_string(str(sig)) self.transport._send_message(m) self.transport._activate_outbound()
def _parse_kexdh_gex_reply(self, m): host_key = m.get_string() self.f = m.get_mpint() sig = m.get_string() if (self.f < 1) or (self.f > self.p - 1): raise SSHException('Server kex "f" is out of range') K = pow(self.f, self.x, self.p) # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K) hm = Message() hm.add(self.transport.local_version, self.transport.remote_version, self.transport.local_kex_init, self.transport.remote_kex_init, host_key) if not self.old_style: hm.add_int(self.min_bits) hm.add_int(self.preferred_bits) if not self.old_style: hm.add_int(self.max_bits) hm.add_mpint(self.p) hm.add_mpint(self.g) hm.add_mpint(self.e) hm.add_mpint(self.f) hm.add_mpint(K) self.transport._set_K_H(K, SHA.new(str(hm)).digest()) self.transport._verify_key(host_key, sig) self.transport._activate_outbound()
def test_1_encode(self): msg = Message() msg.add_int(23) msg.add_int(123789456) msg.add_string('q') msg.add_string('hello') msg.add_string('x' * 1000) self.assertEquals(str(msg), self.__a) msg = Message() msg.add_boolean(True) msg.add_boolean(False) msg.add_byte('\xf3') msg.add_bytes('\x00\x3f') msg.add_list(['huey', 'dewey', 'louie']) self.assertEquals(str(msg), self.__b) msg = Message() msg.add_int64(5) msg.add_int64(0xf5e4d3c2b109L) msg.add_mpint(17) msg.add_mpint(0xf5e4d3c2b109L) msg.add_mpint(-0x65e4d3c2b109L) self.assertEquals(str(msg), self.__c)
def request_forward_agent(self, handler): """ Request for a forward SSH Agent on this channel. This is only valid for an ssh-agent from openssh !!! @param handler: a required handler to use for incoming SSH Agent connections @type handler: function @return: if we are ok or not (at that time we always return ok) @rtype: boolean @raise: SSHException in case of channel problem. """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('*****@*****.**') m.add_boolean(False) self.transport._send_user_message(m) self.transport._set_forward_agent_handler(handler) return True
def start_kex(self, _test_old_style=False): if self.transport.server_mode: self.transport._expect_packet(_MSG_KEXDH_GEX_REQUEST, _MSG_KEXDH_GEX_REQUEST_OLD) return # request a bit range: we accept (min_bits) to (max_bits), but prefer # (preferred_bits). according to the spec, we shouldn't pull the # minimum up above 1024. m = Message() if _test_old_style: # only used for unit tests: we shouldn't ever send this m.add_byte(chr(_MSG_KEXDH_GEX_REQUEST_OLD)) m.add_int(self.preferred_bits) self.old_style = True else: m.add_byte(chr(_MSG_KEXDH_GEX_REQUEST)) m.add_int(self.min_bits) m.add_int(self.preferred_bits) m.add_int(self.max_bits) self.transport._send_message(m) self.transport._expect_packet(_MSG_KEXDH_GEX_GROUP)
def _parse_kexdh_gex_init(self, m): self.e = m.get_mpint() if (self.e < 1) or (self.e > self.p - 1): raise SSHException('Client kex "e" is out of range') self._generate_x() self.f = pow(self.g, self.x, self.p) K = pow(self.e, self.x, self.p) key = str(self.transport.get_server_key()) # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K) hm = Message() hm.add(self.transport.remote_version, self.transport.local_version, self.transport.remote_kex_init, self.transport.local_kex_init, key) if not self.old_style: hm.add_int(self.min_bits) hm.add_int(self.preferred_bits) if not self.old_style: hm.add_int(self.max_bits) hm.add_mpint(self.p) hm.add_mpint(self.g) hm.add_mpint(self.e) hm.add_mpint(self.f) hm.add_mpint(K) H = SHA.new(str(hm)).digest() self.transport._set_K_H(K, H) # sign it sig = self.transport.get_server_key().sign_ssh_data( self.transport.rng, H) # send reply m = Message() m.add_byte(chr(_MSG_KEXDH_GEX_REPLY)) m.add_string(key) m.add_mpint(self.f) m.add_string(str(sig)) self.transport._send_message(m) self.transport._activate_outbound()
@raise socket.timeout: if no data is ready before the timeout set by L{settimeout}. @since: 1.1 """ try: out = self.in_stderr_buffer.read(nbytes, self.timeout) except PipeTimeout, e: raise socket.timeout() ack = self._check_add_window(len(out)) # no need to hold the channel lock when sending this if ack > 0: m = Message() m.add_byte(chr(MSG_CHANNEL_WINDOW_ADJUST)) m.add_int(self.remote_chanid) m.add_int(ack) self.transport._send_user_message(m) return out def send_ready(self): """ Returns true if data can be written to this channel without blocking. This means the channel is either closed (so any write attempt would return immediately) or there is at least one byte of space in the outbound buffer. If there is at least one byte of space in the outbound buffer, a L{send} call will succeed immediately and return the number of bytes actually written. @return: C{True} if a L{send} call on this channel would immediately
def request_x11(self, screen_number=0, auth_protocol=None, auth_cookie=None, single_connection=False, handler=None): """ Request an x11 session on this channel. If the server allows it, further x11 requests can be made from the server to the client, when an x11 application is run in a shell session. From RFC4254:: It is RECOMMENDED that the 'x11 authentication cookie' that is sent be a fake, random cookie, and that the cookie be checked and replaced by the real cookie when a connection request is received. If you omit the auth_cookie, a new secure random 128-bit value will be generated, used, and returned. You will need to use this value to verify incoming x11 requests and replace them with the actual local x11 cookie (which requires some knoweldge of the x11 protocol). If a handler is passed in, the handler is called from another thread whenever a new x11 connection arrives. The default handler queues up incoming x11 connections, which may be retrieved using L{Transport.accept}. The handler's calling signature is:: handler(channel: Channel, (address: str, port: int)) @param screen_number: the x11 screen number (0, 10, etc) @type screen_number: int @param auth_protocol: the name of the X11 authentication method used; if none is given, C{"MIT-MAGIC-COOKIE-1"} is used @type auth_protocol: str @param auth_cookie: hexadecimal string containing the x11 auth cookie; if none is given, a secure random 128-bit value is generated @type auth_cookie: str @param single_connection: if True, only a single x11 connection will be forwarded (by default, any number of x11 connections can arrive over this session) @type single_connection: bool @param handler: an optional handler to use for incoming X11 connections @type handler: function @return: the auth_cookie used """ if self.closed or self.eof_received or self.eof_sent or not self.active: raise SSHException('Channel is not open') if auth_protocol is None: auth_protocol = 'MIT-MAGIC-COOKIE-1' if auth_cookie is None: auth_cookie = binascii.hexlify(self.transport.rng.read(16)) m = Message() m.add_byte(chr(MSG_CHANNEL_REQUEST)) m.add_int(self.remote_chanid) m.add_string('x11-req') m.add_boolean(True) m.add_boolean(single_connection) m.add_string(auth_protocol) m.add_string(auth_cookie) m.add_int(screen_number) self._event_pending() self.transport._send_user_message(m) self._wait_for_event() self.transport._set_x11_handler(handler) return auth_cookie
def _handle_request(self, m): key = m.get_string() want_reply = m.get_boolean() server = self.transport.server_object ok = False if key == 'exit-status': self.exit_status = m.get_int() self.status_event.set() ok = True elif key == 'xon-xoff': # ignore ok = True elif key == 'pty-req': term = m.get_string() width = m.get_int() height = m.get_int() pixelwidth = m.get_int() pixelheight = m.get_int() modes = m.get_string() if server is None: ok = False else: ok = server.check_channel_pty_request(self, term, width, height, pixelwidth, pixelheight, modes) elif key == 'shell': if server is None: ok = False else: ok = server.check_channel_shell_request(self) elif key == 'exec': cmd = m.get_string() if server is None: ok = False else: ok = server.check_channel_exec_request(self, cmd) elif key == 'subsystem': name = m.get_string() if server is None: ok = False else: ok = server.check_channel_subsystem_request(self, name) elif key == 'window-change': width = m.get_int() height = m.get_int() pixelwidth = m.get_int() pixelheight = m.get_int() if server is None: ok = False else: ok = server.check_channel_window_change_request(self, width, height, pixelwidth, pixelheight) elif key == 'x11-req': single_connection = m.get_boolean() auth_proto = m.get_string() auth_cookie = m.get_string() screen_number = m.get_int() if server is None: ok = False else: ok = server.check_channel_x11_request(self, single_connection, auth_proto, auth_cookie, screen_number) elif key == '*****@*****.**': if server is None: ok = False else: ok = server.check_channel_forward_agent_request(self) else: self._log(DEBUG, 'Unhandled channel request "%s"' % key) ok = False if want_reply: m = Message() if ok: m.add_byte(chr(MSG_CHANNEL_SUCCESS)) else: m.add_byte(chr(MSG_CHANNEL_FAILURE)) m.add_int(self.remote_chanid) self.transport._send_user_message(m)
def _handle_request(self, m): key = m.get_string() want_reply = m.get_boolean() server = self.transport.server_object ok = False if key == 'exit-status': self.exit_status = m.get_int() self.status_event.set() ok = True elif key == 'xon-xoff': # ignore ok = True elif key == 'pty-req': term = m.get_string() width = m.get_int() height = m.get_int() pixelwidth = m.get_int() pixelheight = m.get_int() modes = m.get_string() if server is None: ok = False else: ok = server.check_channel_pty_request(self, term, width, height, pixelwidth, pixelheight, modes) elif key == 'shell': if server is None: ok = False else: ok = server.check_channel_shell_request(self) elif key == 'exec': cmd = m.get_string() if server is None: ok = False else: ok = server.check_channel_exec_request(self, cmd) elif key == 'subsystem': name = m.get_string() if server is None: ok = False else: ok = server.check_channel_subsystem_request(self, name) elif key == 'window-change': width = m.get_int() height = m.get_int() pixelwidth = m.get_int() pixelheight = m.get_int() if server is None: ok = False else: ok = server.check_channel_window_change_request( self, width, height, pixelwidth, pixelheight) elif key == 'x11-req': single_connection = m.get_boolean() auth_proto = m.get_string() auth_cookie = m.get_string() screen_number = m.get_int() if server is None: ok = False else: ok = server.check_channel_x11_request(self, single_connection, auth_proto, auth_cookie, screen_number) elif key == '*****@*****.**': if server is None: ok = False else: ok = server.check_channel_forward_agent_request(self) else: self._log(DEBUG, 'Unhandled channel request "%s"' % key) ok = False if want_reply: m = Message() if ok: m.add_byte(chr(MSG_CHANNEL_SUCCESS)) else: m.add_byte(chr(MSG_CHANNEL_FAILURE)) m.add_int(self.remote_chanid) self.transport._send_user_message(m)