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# Copyright (C) 2006-2011 Robey Pointer <robey@lag.net>
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# Copyright (C) 2005, 2006, 2007 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Foundation SSH support for SFTP and smart server."""
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from __future__ import absolute_import
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from binascii import hexlify
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except ImportError as e:
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# If we have an ssh subprocess, we don't strictly need paramiko for all ssh
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from paramiko.sftp_client import SFTPClient
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class StrangeHostname(errors.BzrError):
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_fmt = "Refusing to connect to strange SSH hostname %(hostname)s"
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class SSHVendorManager(object):
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"""Manager for manage SSH vendors."""
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# Note, although at first sign the class interface seems similar to
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# breezy.registry.Registry it is not possible/convenient to directly use
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# the Registry because the class just has "get()" interface instead of the
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# Registry's "get(key)".
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self._ssh_vendors = {}
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self._cached_ssh_vendor = None
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self._default_ssh_vendor = None
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def register_default_vendor(self, vendor):
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"""Register default SSH vendor."""
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self._default_ssh_vendor = vendor
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def register_vendor(self, name, vendor):
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"""Register new SSH vendor by name."""
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self._ssh_vendors[name] = vendor
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def clear_cache(self):
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"""Clear previously cached lookup result."""
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self._cached_ssh_vendor = None
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def _get_vendor_by_environment(self, environment=None):
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"""Return the vendor or None based on BRZ_SSH environment variable.
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:raises UnknownSSH: if the BRZ_SSH environment variable contains
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if environment is None:
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environment = os.environ
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if 'BRZ_SSH' in environment:
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vendor_name = environment['BRZ_SSH']
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vendor = self._ssh_vendors[vendor_name]
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vendor = self._get_vendor_from_path(vendor_name)
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raise errors.UnknownSSH(vendor_name)
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vendor.executable_path = vendor_name
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def _get_ssh_version_string(self, args):
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"""Return SSH version string from the subprocess."""
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p = subprocess.Popen(args,
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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**os_specific_subprocess_params())
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stdout, stderr = p.communicate()
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stdout = stderr = b''
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return (stdout + stderr).decode(osutils.get_terminal_encoding())
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def _get_vendor_by_version_string(self, version, progname):
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"""Return the vendor or None based on output from the subprocess.
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:param version: The output of 'ssh -V' like command.
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:param args: Command line that was run.
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if 'OpenSSH' in version:
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trace.mutter('ssh implementation is OpenSSH')
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vendor = OpenSSHSubprocessVendor()
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elif 'SSH Secure Shell' in version:
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trace.mutter('ssh implementation is SSH Corp.')
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vendor = SSHCorpSubprocessVendor()
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elif 'lsh' in version:
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trace.mutter('ssh implementation is GNU lsh.')
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vendor = LSHSubprocessVendor()
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# As plink user prompts are not handled currently, don't auto-detect
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# it by inspection below, but keep this vendor detection for if a path
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# is given in BRZ_SSH. See https://bugs.launchpad.net/bugs/414743
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elif 'plink' in version and progname == 'plink':
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# Checking if "plink" was the executed argument as Windows
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# sometimes reports 'ssh -V' incorrectly with 'plink' in its
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# version. See https://bugs.launchpad.net/bzr/+bug/107155
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trace.mutter("ssh implementation is Putty's plink.")
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vendor = PLinkSubprocessVendor()
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def _get_vendor_by_inspection(self):
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"""Return the vendor or None by checking for known SSH implementations."""
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version = self._get_ssh_version_string(['ssh', '-V'])
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return self._get_vendor_by_version_string(version, "ssh")
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def _get_vendor_from_path(self, path):
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"""Return the vendor or None using the program at the given path"""
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version = self._get_ssh_version_string([path, '-V'])
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return self._get_vendor_by_version_string(version,
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os.path.splitext(os.path.basename(path))[0])
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def get_vendor(self, environment=None):
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"""Find out what version of SSH is on the system.
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:raises SSHVendorNotFound: if no any SSH vendor is found
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:raises UnknownSSH: if the BRZ_SSH environment variable contains
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if self._cached_ssh_vendor is None:
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vendor = self._get_vendor_by_environment(environment)
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vendor = self._get_vendor_by_inspection()
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trace.mutter('falling back to default implementation')
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vendor = self._default_ssh_vendor
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raise errors.SSHVendorNotFound()
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self._cached_ssh_vendor = vendor
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return self._cached_ssh_vendor
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_ssh_vendor_manager = SSHVendorManager()
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_get_ssh_vendor = _ssh_vendor_manager.get_vendor
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register_default_ssh_vendor = _ssh_vendor_manager.register_default_vendor
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register_ssh_vendor = _ssh_vendor_manager.register_vendor
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def _ignore_signals():
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# TODO: This should possibly ignore SIGHUP as well, but bzr currently
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# doesn't handle it itself.
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# <https://launchpad.net/products/bzr/+bug/41433/+index>
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signal.signal(signal.SIGINT, signal.SIG_IGN)
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# GZ 2010-02-19: Perhaps make this check if breakin is installed instead
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if signal.getsignal(signal.SIGQUIT) != signal.SIG_DFL:
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signal.signal(signal.SIGQUIT, signal.SIG_IGN)
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class SocketAsChannelAdapter(object):
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"""Simple wrapper for a socket that pretends to be a paramiko Channel."""
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def __init__(self, sock):
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return "bzr SocketAsChannelAdapter"
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def send(self, data):
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return self.__socket.send(data)
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return self.__socket.recv(n)
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except socket.error as e:
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if e.args[0] in (errno.EPIPE, errno.ECONNRESET, errno.ECONNABORTED,
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# Connection has closed. Paramiko expects an empty string in
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# this case, not an exception.
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def recv_ready(self):
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# TODO: jam 20051215 this function is necessary to support the
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# pipelined() function. In reality, it probably should use
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# poll() or select() to actually return if there is data
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# available, otherwise we probably don't get any benefit
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self.__socket.close()
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class SSHVendor(object):
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"""Abstract base class for SSH vendor implementations."""
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def connect_sftp(self, username, password, host, port):
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"""Make an SSH connection, and return an SFTPClient.
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:param username: an ascii string
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:param password: an ascii string
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:param host: a host name as an ascii string
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:param port: a port number
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:raises: ConnectionError if it cannot connect.
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:rtype: paramiko.sftp_client.SFTPClient
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raise NotImplementedError(self.connect_sftp)
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def connect_ssh(self, username, password, host, port, command):
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"""Make an SSH connection.
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:returns: an SSHConnection.
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raise NotImplementedError(self.connect_ssh)
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def _raise_connection_error(self, host, port=None, orig_error=None,
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msg='Unable to connect to SSH host'):
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"""Raise a SocketConnectionError with properly formatted host.
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This just unifies all the locations that try to raise ConnectionError,
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so that they format things properly.
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raise errors.SocketConnectionError(host=host, port=port, msg=msg,
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orig_error=orig_error)
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class LoopbackVendor(SSHVendor):
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"""SSH "vendor" that connects over a plain TCP socket, not SSH."""
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def connect_sftp(self, username, password, host, port):
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sock = socket.socket()
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sock.connect((host, port))
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except socket.error as e:
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self._raise_connection_error(host, port=port, orig_error=e)
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return SFTPClient(SocketAsChannelAdapter(sock))
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register_ssh_vendor('loopback', LoopbackVendor())
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class ParamikoVendor(SSHVendor):
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"""Vendor that uses paramiko."""
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def _hexify(self, s):
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return hexlify(s).upper()
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def _connect(self, username, password, host, port):
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global SYSTEM_HOSTKEYS, BRZ_HOSTKEYS
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t = paramiko.Transport((host, port or 22))
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t.set_log_channel('bzr.paramiko')
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except (paramiko.SSHException, socket.error) as e:
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self._raise_connection_error(host, port=port, orig_error=e)
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server_key = t.get_remote_server_key()
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server_key_hex = self._hexify(server_key.get_fingerprint())
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keytype = server_key.get_name()
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if host in SYSTEM_HOSTKEYS and keytype in SYSTEM_HOSTKEYS[host]:
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our_server_key = SYSTEM_HOSTKEYS[host][keytype]
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our_server_key_hex = self._hexify(our_server_key.get_fingerprint())
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elif host in BRZ_HOSTKEYS and keytype in BRZ_HOSTKEYS[host]:
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our_server_key = BRZ_HOSTKEYS[host][keytype]
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our_server_key_hex = self._hexify(our_server_key.get_fingerprint())
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trace.warning('Adding %s host key for %s: %s'
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% (keytype, host, server_key_hex))
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add = getattr(BRZ_HOSTKEYS, 'add', None)
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if add is not None: # paramiko >= 1.X.X
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BRZ_HOSTKEYS.add(host, keytype, server_key)
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BRZ_HOSTKEYS.setdefault(host, {})[keytype] = server_key
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our_server_key = server_key
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our_server_key_hex = self._hexify(our_server_key.get_fingerprint())
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if server_key != our_server_key:
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filename1 = os.path.expanduser('~/.ssh/known_hosts')
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filename2 = osutils.pathjoin(config.config_dir(), 'ssh_host_keys')
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raise errors.TransportError(
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'Host keys for %s do not match! %s != %s' %
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(host, our_server_key_hex, server_key_hex),
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['Try editing %s or %s' % (filename1, filename2)])
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_paramiko_auth(username, password, host, port, t)
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def connect_sftp(self, username, password, host, port):
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t = self._connect(username, password, host, port)
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return t.open_sftp_client()
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except paramiko.SSHException as e:
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self._raise_connection_error(host, port=port, orig_error=e,
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msg='Unable to start sftp client')
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def connect_ssh(self, username, password, host, port, command):
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t = self._connect(username, password, host, port)
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channel = t.open_session()
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cmdline = ' '.join(command)
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channel.exec_command(cmdline)
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return _ParamikoSSHConnection(channel)
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except paramiko.SSHException as e:
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self._raise_connection_error(host, port=port, orig_error=e,
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msg='Unable to invoke remote bzr')
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_ssh_connection_errors = (EOFError, OSError, IOError, socket.error)
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if paramiko is not None:
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vendor = ParamikoVendor()
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register_ssh_vendor('paramiko', vendor)
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register_ssh_vendor('none', vendor)
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register_default_ssh_vendor(vendor)
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_ssh_connection_errors += (paramiko.SSHException,)
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class SubprocessVendor(SSHVendor):
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"""Abstract base class for vendors that use pipes to a subprocess."""
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# In general stderr should be inherited from the parent process so prompts
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# are visible on the terminal. This can be overriden to another file for
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# tests, but beware of using PIPE which may hang due to not being read.
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_stderr_target = None
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def _check_hostname(arg):
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if arg.startswith('-'):
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raise StrangeHostname(hostname=arg)
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def _connect(self, argv):
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# Attempt to make a socketpair to use as stdin/stdout for the SSH
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# subprocess. We prefer sockets to pipes because they support
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# non-blocking short reads, allowing us to optimistically read 64k (or
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my_sock, subproc_sock = socket.socketpair()
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osutils.set_fd_cloexec(my_sock)
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except (AttributeError, socket.error):
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# This platform doesn't support socketpair(), so just use ordinary
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stdin = stdout = subprocess.PIPE
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my_sock, subproc_sock = None, None
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stdin = stdout = subproc_sock
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proc = subprocess.Popen(argv, stdin=stdin, stdout=stdout,
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stderr=self._stderr_target,
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**os_specific_subprocess_params())
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if subproc_sock is not None:
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return SSHSubprocessConnection(proc, sock=my_sock)
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def connect_sftp(self, username, password, host, port):
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argv = self._get_vendor_specific_argv(username, host, port,
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sock = self._connect(argv)
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return SFTPClient(SocketAsChannelAdapter(sock))
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except _ssh_connection_errors as e:
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self._raise_connection_error(host, port=port, orig_error=e)
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def connect_ssh(self, username, password, host, port, command):
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argv = self._get_vendor_specific_argv(username, host, port,
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return self._connect(argv)
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except _ssh_connection_errors as e:
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self._raise_connection_error(host, port=port, orig_error=e)
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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"""Returns the argument list to run the subprocess with.
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Exactly one of 'subsystem' and 'command' must be specified.
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raise NotImplementedError(self._get_vendor_specific_argv)
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class OpenSSHSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'ssh' executable from OpenSSH."""
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executable_path = 'ssh'
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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args = [self.executable_path,
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'-oForwardX11=no', '-oForwardAgent=no',
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'-oClearAllForwardings=yes',
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'-oNoHostAuthenticationForLocalhost=yes']
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args.extend(['-p', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['-s', '--', host, subsystem])
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args.extend(['--', host] + command)
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register_ssh_vendor('openssh', OpenSSHSubprocessVendor())
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class SSHCorpSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'ssh' executable from SSH Corporation."""
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executable_path = 'ssh'
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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self._check_hostname(host)
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args = [self.executable_path, '-x']
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args.extend(['-p', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['-s', subsystem, host])
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args.extend([host] + command)
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register_ssh_vendor('sshcorp', SSHCorpSubprocessVendor())
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class LSHSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'lsh' executable from GNU"""
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executable_path = 'lsh'
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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self._check_hostname(host)
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args = [self.executable_path]
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args.extend(['-p', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['--subsystem', subsystem, host])
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args.extend([host] + command)
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register_ssh_vendor('lsh', LSHSubprocessVendor())
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class PLinkSubprocessVendor(SubprocessVendor):
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"""SSH vendor that uses the 'plink' executable from Putty."""
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executable_path = 'plink'
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def _get_vendor_specific_argv(self, username, host, port, subsystem=None,
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self._check_hostname(host)
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args = [self.executable_path, '-x', '-a', '-ssh', '-2', '-batch']
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args.extend(['-P', str(port)])
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if username is not None:
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args.extend(['-l', username])
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if subsystem is not None:
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args.extend(['-s', host, subsystem])
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args.extend([host] + command)
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register_ssh_vendor('plink', PLinkSubprocessVendor())
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def _paramiko_auth(username, password, host, port, paramiko_transport):
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auth = config.AuthenticationConfig()
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# paramiko requires a username, but it might be none if nothing was
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# supplied. If so, use the local username.
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username = auth.get_user('ssh', host, port=port,
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default=getpass.getuser())
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agent = paramiko.Agent()
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for key in agent.get_keys():
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trace.mutter('Trying SSH agent key %s'
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% hexlify(key.get_fingerprint()).upper())
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paramiko_transport.auth_publickey(username, key)
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except paramiko.SSHException as e:
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# okay, try finding id_rsa or id_dss? (posix only)
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if _try_pkey_auth(paramiko_transport, paramiko.RSAKey, username, 'id_rsa'):
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if _try_pkey_auth(paramiko_transport, paramiko.DSSKey, username, 'id_dsa'):
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# If we have gotten this far, we are about to try for passwords, do an
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# auth_none check to see if it is even supported.
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supported_auth_types = []
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# Note that with paramiko <1.7.5 this logs an INFO message:
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# Authentication type (none) not permitted.
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# So we explicitly disable the logging level for this action
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old_level = paramiko_transport.logger.level
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paramiko_transport.logger.setLevel(logging.WARNING)
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paramiko_transport.auth_none(username)
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paramiko_transport.logger.setLevel(old_level)
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except paramiko.BadAuthenticationType as e:
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# Supported methods are in the exception
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supported_auth_types = e.allowed_types
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except paramiko.SSHException as e:
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# Don't know what happened, but just ignore it
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# We treat 'keyboard-interactive' and 'password' auth methods identically,
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# because Paramiko's auth_password method will automatically try
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# 'keyboard-interactive' auth (using the password as the response) if
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# 'password' auth is not available. Apparently some Debian and Gentoo
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# OpenSSH servers require this.
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# XXX: It's possible for a server to require keyboard-interactive auth that
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# requires something other than a single password, but we currently don't
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if ('password' not in supported_auth_types and
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'keyboard-interactive' not in supported_auth_types):
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raise errors.ConnectionError('Unable to authenticate to SSH host as'
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'\n %s@%s\nsupported auth types: %s'
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% (username, host, supported_auth_types))
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paramiko_transport.auth_password(username, password)
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except paramiko.SSHException as e:
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# give up and ask for a password
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password = auth.get_password('ssh', host, username, port=port)
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# get_password can still return None, which means we should not prompt
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if password is not None:
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paramiko_transport.auth_password(username, password)
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except paramiko.SSHException as e:
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raise errors.ConnectionError(
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'Unable to authenticate to SSH host as'
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'\n %s@%s\n' % (username, host), e)
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raise errors.ConnectionError('Unable to authenticate to SSH host as'
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' %s@%s' % (username, host))
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def _try_pkey_auth(paramiko_transport, pkey_class, username, filename):
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filename = os.path.expanduser('~/.ssh/' + filename)
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key = pkey_class.from_private_key_file(filename)
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paramiko_transport.auth_publickey(username, key)
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except paramiko.PasswordRequiredException:
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password = ui.ui_factory.get_password(
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prompt=u'SSH %(filename)s password',
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filename=filename.decode(osutils._fs_enc))
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key = pkey_class.from_private_key_file(filename, password)
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paramiko_transport.auth_publickey(username, key)
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except paramiko.SSHException:
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trace.mutter('SSH authentication via %s key failed.'
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% (os.path.basename(filename),))
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except paramiko.SSHException:
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trace.mutter('SSH authentication via %s key failed.'
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% (os.path.basename(filename),))
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def load_host_keys():
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Load system host keys (probably doesn't work on windows) and any
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"discovered" keys from previous sessions.
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global SYSTEM_HOSTKEYS, BRZ_HOSTKEYS
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SYSTEM_HOSTKEYS = paramiko.util.load_host_keys(
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os.path.expanduser('~/.ssh/known_hosts'))
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trace.mutter('failed to load system host keys: ' + str(e))
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brz_hostkey_path = osutils.pathjoin(config.config_dir(), 'ssh_host_keys')
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BRZ_HOSTKEYS = paramiko.util.load_host_keys(brz_hostkey_path)
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trace.mutter('failed to load brz host keys: ' + str(e))
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def save_host_keys():
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Save "discovered" host keys in $(config)/ssh_host_keys/.
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global SYSTEM_HOSTKEYS, BRZ_HOSTKEYS
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bzr_hostkey_path = osutils.pathjoin(config.config_dir(), 'ssh_host_keys')
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config.ensure_config_dir_exists()
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with open(bzr_hostkey_path, 'w') as f:
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f.write('# SSH host keys collected by bzr\n')
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for hostname, keys in BRZ_HOSTKEYS.items():
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for keytype, key in keys.items():
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f.write('%s %s %s\n' %
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(hostname, keytype, key.get_base64()))
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trace.mutter('failed to save bzr host keys: ' + str(e))
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def os_specific_subprocess_params():
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"""Get O/S specific subprocess parameters."""
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if sys.platform == 'win32':
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# setting the process group and closing fds is not supported on
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# We close fds other than the pipes as the child process does not need
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# We also set the child process to ignore SIGINT. Normally the signal
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# would be sent to every process in the foreground process group, but
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# this causes it to be seen only by bzr and not by ssh. Python will
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# generate a KeyboardInterrupt in bzr, and we will then have a chance
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# to release locks or do other cleanup over ssh before the connection
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# <https://launchpad.net/products/bzr/+bug/5987>
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# Running it in a separate process group is not good because then it
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# can't get non-echoed input of a password or passphrase.
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# <https://launchpad.net/products/bzr/+bug/40508>
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return {'preexec_fn': _ignore_signals,
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_subproc_weakrefs = set()
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def _close_ssh_proc(proc, sock):
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"""Carefully close stdin/stdout and reap the SSH process.
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If the pipes are already closed and/or the process has already been
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wait()ed on, that's ok, and no error is raised. The goal is to do our best
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to clean up (whether or not a clean up was already tried).
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for closeable in (proc.stdin, proc.stdout, sock):
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# We expect that either proc (a subprocess.Popen) will have stdin and
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# stdout streams to close, or that we will have been passed a socket to
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# close, with the option not in use being None.
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if closeable is not None:
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funcs.append(closeable.close)
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funcs.append(proc.wait)
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# It's ok for the pipe to already be closed, or the process to
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# already be finished.
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class SSHConnection(object):
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"""Abstract base class for SSH connections."""
708
def get_sock_or_pipes(self):
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"""Returns a (kind, io_object) pair.
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If kind == 'socket', then io_object is a socket.
713
If kind == 'pipes', then io_object is a pair of file-like objects
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(read_from, write_to).
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raise NotImplementedError(self.get_sock_or_pipes)
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raise NotImplementedError(self.close)
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class SSHSubprocessConnection(SSHConnection):
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"""A connection to an ssh subprocess via pipes or a socket.
725
This class is also socket-like enough to be used with
726
SocketAsChannelAdapter (it has 'send' and 'recv' methods).
729
def __init__(self, proc, sock=None):
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:param proc: a subprocess.Popen
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:param sock: if proc.stdin/out is a socket from a socketpair, then sock
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should breezy's half of that socketpair. If not passed, proc's
735
stdin/out is assumed to be ordinary pipes.
739
# Add a weakref to proc that will attempt to do the same as self.close
740
# to avoid leaving processes lingering indefinitely.
743
_subproc_weakrefs.remove(ref)
744
_close_ssh_proc(proc, sock)
745
_subproc_weakrefs.add(weakref.ref(self, terminate))
747
def send(self, data):
748
if self._sock is not None:
749
return self._sock.send(data)
751
return os.write(self.proc.stdin.fileno(), data)
753
def recv(self, count):
754
if self._sock is not None:
755
return self._sock.recv(count)
757
return os.read(self.proc.stdout.fileno(), count)
760
_close_ssh_proc(self.proc, self._sock)
762
def get_sock_or_pipes(self):
763
if self._sock is not None:
764
return 'socket', self._sock
766
return 'pipes', (self.proc.stdout, self.proc.stdin)
769
class _ParamikoSSHConnection(SSHConnection):
770
"""An SSH connection via paramiko."""
772
def __init__(self, channel):
773
self.channel = channel
775
def get_sock_or_pipes(self):
776
return ('socket', self.channel)
779
return self.channel.close()
added
removed
breezy/transport/ssh.py
