# Copyright (C) 2006-2007 Robey Pointer # Copyright (C) 2012 Olle Lundberg # # This file is part of paramiko. # # Paramiko is free software; you can redistribute it and/or modify it under the # terms of the GNU Lesser General Public License as published by the Free # Software Foundation; either version 2.1 of the License, or (at your option) # any later version. # # Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR # A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more # details. # # You should have received a copy of the GNU Lesser General Public License # along with Paramiko; if not, write to the Free Software Foundation, Inc., # 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. """ Configuration file (aka ``ssh_config``) support. """ import fnmatch import os import re import socket SSH_PORT = 22 proxy_re = re.compile(r"^(proxycommand)\s*=*\s*(.*)", re.I) class SSHConfig (object): """ Representation of config information as stored in the format used by OpenSSH. Queries can be made via `lookup`. The format is described in OpenSSH's ``ssh_config`` man page. This class is provided primarily as a convenience to posix users (since the OpenSSH format is a de-facto standard on posix) but should work fine on Windows too. .. versionadded:: 1.6 """ def __init__(self): """ Create a new OpenSSH config object. """ self._config = [] def parse(self, file_obj): """ Read an OpenSSH config from the given file object. :param file file_obj: a file-like object to read the config file from """ host = {"host": ['*'], "config": {}} for line in file_obj: line = line.rstrip('\r\n').lstrip() if not line or line.startswith('#'): continue if '=' in line: # Ensure ProxyCommand gets properly split if line.lower().strip().startswith('proxycommand'): match = proxy_re.match(line) key, value = match.group(1).lower(), match.group(2) else: key, value = line.split('=', 1) key = key.strip().lower() else: # find first whitespace, and split there i = 0 while (i < len(line)) and not line[i].isspace(): i += 1 if i == len(line): raise Exception('Unparsable line: %r' % line) key = line[:i].lower() value = line[i:].lstrip() if key == 'host': self._config.append(host) value = value.split() host = {key: value, 'config': {}} #identityfile, localforward, remoteforward keys are special cases, since they are allowed to be # specified multiple times and they should be tried in order # of specification. elif key in ['identityfile', 'localforward', 'remoteforward']: if key in host['config']: host['config'][key].append(value) else: host['config'][key] = [value] elif key not in host['config']: host['config'][key] = value self._config.append(host) def lookup(self, hostname): """ Return a dict of config options for a given hostname. The host-matching rules of OpenSSH's ``ssh_config`` man page are used, which means that all configuration options from matching host specifications are merged, with more specific hostmasks taking precedence. In other words, if ``"Port"`` is set under ``"Host *"`` and also ``"Host *.example.com"``, and the lookup is for ``"ssh.example.com"``, then the port entry for ``"Host *.example.com"`` will win out. The keys in the returned dict are all normalized to lowercase (look for ``"port"``, not ``"Port"``. The values are processed according to the rules for substitution variable expansion in ``ssh_config``. :param str hostname: the hostname to lookup """ matches = [ config for config in self._config if self._allowed(config['host'], hostname) ] ret = {} for match in matches: for key, value in match['config'].items(): if key not in ret: # Create a copy of the original value, # else it will reference the original list # in self._config and update that value too # when the extend() is being called. ret[key] = value[:] elif key == 'identityfile': ret[key].extend(value) ret = self._expand_variables(ret, hostname) return ret def _allowed(self, hosts, hostname): match = False for host in hosts: if host.startswith('!') and fnmatch.fnmatch(hostname, host[1:]): return False elif fnmatch.fnmatch(hostname, host): match = True return match def _expand_variables(self, config, hostname): """ Return a dict of config options with expanded substitutions for a given hostname. Please refer to man ``ssh_config`` for the parameters that are replaced. :param dict config: the config for the hostname :param str hostname: the hostname that the config belongs to """ if 'hostname' in config: config['hostname'] = config['hostname'].replace('%h', hostname) else: config['hostname'] = hostname if 'port' in config: port = config['port'] else: port = SSH_PORT user = os.getenv('USER') if 'user' in config: remoteuser = config['user'] else: remoteuser = user host = socket.gethostname().split('.')[0] fqdn = LazyFqdn(config, host) homedir = os.path.expanduser('~') replacements = {'controlpath': [ ('%h', config['hostname']), ('%l', fqdn), ('%L', host), ('%n', hostname), ('%p', port), ('%r', remoteuser), ('%u', user) ], 'identityfile': [ ('~', homedir), ('%d', homedir), ('%h', config['hostname']), ('%l', fqdn), ('%u', user), ('%r', remoteuser) ], 'proxycommand': [ ('%h', config['hostname']), ('%p', port), ('%r', remoteuser) ] } for k in config: if k in replacements: for find, replace in replacements[k]: if isinstance(config[k], list): for item in range(len(config[k])): if find in config[k][item]: config[k][item] = config[k][item].\ replace(find, str(replace)) else: if find in config[k]: config[k] = config[k].replace(find, str(replace)) return config class LazyFqdn(object): """ Returns the host's fqdn on request as string. """ def __init__(self, config, host=None): self.fqdn = None self.config = config self.host = host def __str__(self): if self.fqdn is None: # # If the SSH config contains AddressFamily, use that when # determining the local host's FQDN. Using socket.getfqdn() from # the standard library is the most general solution, but can # result in noticeable delays on some platforms when IPv6 is # misconfigured or not available, as it calls getaddrinfo with no # address family specified, so both IPv4 and IPv6 are checked. # # Handle specific option fqdn = None address_family = self.config.get('addressfamily', 'any').lower() if address_family != 'any': try: family = socket.AF_INET if address_family == 'inet' \ else socket.AF_INET6 results = socket.getaddrinfo( self.host, None, family, socket.SOCK_DGRAM, socket.IPPROTO_IP, socket.AI_CANONNAME ) for res in results: af, socktype, proto, canonname, sa = res if canonname and '.' in canonname: fqdn = canonname break # giaerror -> socket.getaddrinfo() can't resolve self.host # (which is from socket.gethostname()). Fall back to the # getfqdn() call below. except socket.gaierror: pass # Handle 'any' / unspecified if fqdn is None: fqdn = socket.getfqdn() # Cache self.fqdn = fqdn return self.fqdn