bc3445881f
Introduce a get_instance factory method for all plugins and other xmpp related classes. This will help us to decouple plugs in order to make them testable.
393 lines
12 KiB
Python
393 lines
12 KiB
Python
## tls_nb.py
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## based on transports_nb.py
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##
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## Copyright (C) 2003-2004 Alexey "Snake" Nezhdanov
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## modified by Dimitur Kirov <dkirov@gmail.com>
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## modified by Tomas Karasek <tom.to.the.k@gmail.com>
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##
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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, or (at your option)
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## any later version.
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##
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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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import socket
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from plugin import PlugIn
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import sys
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import os
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import time
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import traceback
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import logging
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log = logging.getLogger('gajim.c.x.tls_nb')
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USE_PYOPENSSL = False
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PYOPENSSL = 'PYOPENSSL'
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PYSTDLIB = 'PYSTDLIB'
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try:
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#raise ImportError("Manually disabled PyOpenSSL")
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import OpenSSL.SSL
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import OpenSSL.crypto
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USE_PYOPENSSL = True
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log.info("PyOpenSSL loaded")
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except ImportError:
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log.debug("Import of PyOpenSSL failed:", exc_info=True)
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# FIXME: Remove these prints before release, replace with a warning dialog.
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print >> sys.stderr, "=" * 79
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print >> sys.stderr, "PyOpenSSL not found, falling back to Python builtin SSL objects (insecure)."
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print >> sys.stderr, "=" * 79
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def gattr(obj, attr, default=None):
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try:
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return getattr(obj, attr)
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except AttributeError:
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return default
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class SSLWrapper:
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'''
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Abstract SSLWrapper base class
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'''
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class Error(IOError):
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''' Generic SSL Error Wrapper '''
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def __init__(self, sock=None, exc=None, errno=None, strerror=None,
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peer=None):
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self.parent = IOError
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errno = errno or gattr(exc, 'errno')
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strerror = strerror or gattr(exc, 'strerror') or gattr(exc, 'args')
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if not isinstance(strerror, basestring):
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strerror = repr(strerror)
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self.sock = sock
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self.exc = exc
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self.peer = peer
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self.exc_name = None
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self.exc_args = None
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self.exc_str = None
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self.exc_repr = None
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if self.exc is not None:
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self.exc_name = str(self.exc.__class__)
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self.exc_args = gattr(self.exc, 'args')
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self.exc_str = str(self.exc)
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self.exc_repr = repr(self.exc)
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if not errno:
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try:
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if isinstance(exc, OpenSSL.SSL.SysCallError):
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if self.exc_args[0] > 0:
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errno = self.exc_args[0]
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strerror = self.exc_args[1]
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except: pass
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self.parent.__init__(self, errno, strerror)
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if self.peer is None and sock is not None:
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try:
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ppeer = self.sock.getpeername()
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if len(ppeer) == 2 and isinstance(ppeer[0], basestring) \
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and isinstance(ppeer[1], int):
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self.peer = ppeer
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except:
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pass
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def __str__(self):
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s = str(self.__class__)
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if self.peer:
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s += " for %s:%d" % self.peer
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if self.errno is not None:
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s += ": [Errno: %d]" % self.errno
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if self.strerror:
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s += " (%s)" % self.strerror
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if self.exc_name:
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s += ", Caused by %s" % self.exc_name
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if self.exc_str:
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if self.strerror:
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s += "(%s)" % self.exc_str
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else: s += "(%s)" % str(self.exc_args)
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return s
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def __init__(self, sslobj, sock=None):
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self.sslobj = sslobj
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self.sock = sock
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log.debug("%s.__init__ called with %s", self.__class__, sslobj)
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def recv(self, data, flags=None):
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'''
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Receive wrapper for SSL object
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We can return None out of this function to signal that no data is
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available right now. Better than an exception, which differs
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depending on which SSL lib we're using. Unfortunately returning ''
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can indicate that the socket has been closed, so to be sure, we avoid
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this by returning None.
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'''
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raise NotImplementedError
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def send(self, data, flags=None, now=False):
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''' Send wrapper for SSL object '''
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raise NotImplementedError
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class PyOpenSSLWrapper(SSLWrapper):
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'''Wrapper class for PyOpenSSL's recv() and send() methods'''
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def __init__(self, *args):
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self.parent = SSLWrapper
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self.parent.__init__(self, *args)
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def is_numtoolarge(self, e):
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''' Magic methods don't need documentation '''
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t = ('asn1 encoding routines', 'a2d_ASN1_OBJECT', 'first num too large')
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return (isinstance(e.args, (list, tuple)) and len(e.args) == 1 and
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isinstance(e.args[0], (list, tuple)) and len(e.args[0]) == 2 and
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e.args[0][0] == e.args[0][1] == t)
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def recv(self, bufsize, flags=None):
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retval = None
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try:
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if flags is None:
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retval = self.sslobj.recv(bufsize)
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else:
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retval = self.sslobj.recv(bufsize, flags)
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except (OpenSSL.SSL.WantReadError, OpenSSL.SSL.WantWriteError), e:
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log.debug("Recv: Want-error: " + repr(e))
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except OpenSSL.SSL.SysCallError, e:
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log.debug("Recv: Got OpenSSL.SSL.SysCallError: " + repr(e),
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exc_info=True)
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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except OpenSSL.SSL.Error, e:
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if self.is_numtoolarge(e):
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# warn, but ignore this exception
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log.warning("Recv: OpenSSL: asn1enc: first num too large (ignored)")
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else:
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log.debug("Recv: Caught OpenSSL.SSL.Error:", exc_info=True)
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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return retval
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def send(self, data, flags=None, now=False):
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try:
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if flags is None:
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return self.sslobj.send(data)
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else:
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return self.sslobj.send(data, flags)
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except (OpenSSL.SSL.WantReadError, OpenSSL.SSL.WantWriteError), e:
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#log.debug("Send: " + repr(e))
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time.sleep(0.1) # prevent 100% CPU usage
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except OpenSSL.SSL.SysCallError, e:
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log.error("Send: Got OpenSSL.SSL.SysCallError: " + repr(e),
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exc_info=True)
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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except OpenSSL.SSL.Error, e:
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if self.is_numtoolarge(e):
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# warn, but ignore this exception
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log.warning("Send: OpenSSL: asn1enc: first num too large (ignored)")
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else:
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log.error("Send: Caught OpenSSL.SSL.Error:", exc_info=True)
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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return 0
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class StdlibSSLWrapper(SSLWrapper):
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'''Wrapper class for Python socket.ssl read() and write() methods'''
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def __init__(self, *args):
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self.parent = SSLWrapper
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self.parent.__init__(self, *args)
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def recv(self, bufsize, flags=None):
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# we simply ignore flags since ssl object doesn't support it
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try:
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return self.sslobj.read(bufsize)
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except socket.sslerror, e:
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log.debug("Recv: Caught socket.sslerror: " + repr(e), exc_info=True)
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if e.args[0] not in (socket.SSL_ERROR_WANT_READ, socket.SSL_ERROR_WANT_WRITE):
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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return None
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def send(self, data, flags=None, now=False):
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# we simply ignore flags since ssl object doesn't support it
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try:
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return self.sslobj.write(data)
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except socket.sslerror, e:
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log.debug("Send: Caught socket.sslerror:", exc_info=True)
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if e.args[0] not in (socket.SSL_ERROR_WANT_READ, socket.SSL_ERROR_WANT_WRITE):
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raise SSLWrapper.Error(self.sock or self.sslobj, e)
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return 0
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class NonBlockingTLS(PlugIn):
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'''
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TLS connection used to encrypts already estabilished tcp connection.
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Can be plugged into NonBlockingTCP and will make use of StdlibSSLWrapper or
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PyOpenSSLWrapper.
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'''
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def __init__(self, cacerts, mycerts):
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'''
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:param cacerts: path to pem file with certificates of known XMPP servers
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:param mycerts: path to pem file with certificates of user trusted servers
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'''
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PlugIn.__init__(self)
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self.cacerts = cacerts
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self.mycerts = mycerts
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# from ssl.h (partial extract)
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ssl_h_bits = { "SSL_ST_CONNECT": 0x1000, "SSL_ST_ACCEPT": 0x2000,
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"SSL_CB_LOOP": 0x01, "SSL_CB_EXIT": 0x02,
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"SSL_CB_READ": 0x04, "SSL_CB_WRITE": 0x08,
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"SSL_CB_ALERT": 0x4000,
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"SSL_CB_HANDSHAKE_START": 0x10, "SSL_CB_HANDSHAKE_DONE": 0x20}
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def plugin(self, owner):
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'''
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Use to PlugIn TLS into transport and start establishing immediately
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Returns True if TLS/SSL was established correctly, otherwise False.
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'''
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log.info('Starting TLS estabilishing')
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try:
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res = self._startSSL()
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except Exception, e:
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log.error("PlugIn: while trying _startSSL():", exc_info=True)
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return False
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return res
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def _dumpX509(self, cert, stream=sys.stderr):
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print >> stream, "Digest (SHA-1):", cert.digest("sha1")
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print >> stream, "Digest (MD5):", cert.digest("md5")
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print >> stream, "Serial #:", cert.get_serial_number()
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print >> stream, "Version:", cert.get_version()
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print >> stream, "Expired:", ("Yes" if cert.has_expired() else "No")
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print >> stream, "Subject:"
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self._dumpX509Name(cert.get_subject(), stream)
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print >> stream, "Issuer:"
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self._dumpX509Name(cert.get_issuer(), stream)
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self._dumpPKey(cert.get_pubkey(), stream)
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def _dumpX509Name(self, name, stream=sys.stderr):
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print >> stream, "X509Name:", str(name)
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def _dumpPKey(self, pkey, stream=sys.stderr):
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typedict = {OpenSSL.crypto.TYPE_RSA: "RSA",
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OpenSSL.crypto.TYPE_DSA: "DSA"}
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print >> stream, "PKey bits:", pkey.bits()
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print >> stream, "PKey type: %s (%d)" % (typedict.get(pkey.type(),
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"Unknown"), pkey.type())
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def _startSSL(self):
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''' Immediatedly switch socket to TLS mode. Used internally.'''
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log.debug("_startSSL called")
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if USE_PYOPENSSL:
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result = self._startSSL_pyOpenSSL()
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else:
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result = self._startSSL_stdlib()
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if result:
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log.debug('Synchronous handshake completed')
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return True
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else:
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return False
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def _load_user_certs(self, cert_path, cert_store):
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if not os.path.isfile(cert_path):
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return
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f = open(cert_path)
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lines = f.readlines()
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i = 0
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begin = -1
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for line in lines:
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if 'BEGIN CERTIFICATE' in line:
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begin = i
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elif 'END CERTIFICATE' in line and begin > -1:
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cert = ''.join(lines[begin:i+2])
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try:
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x509cert = OpenSSL.crypto.load_certificate(
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OpenSSL.crypto.FILETYPE_PEM, cert)
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cert_store.add_cert(x509cert)
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except OpenSSL.crypto.Error, exception_obj:
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log.warning('Unable to load a certificate from file %s: %s' %\
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(self.mycerts, exception_obj.args[0][0][2]))
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except:
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log.warning('Unknown error while loading certificate from file%s'
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% self.mycerts)
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begin = -1
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i += 1
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def _startSSL_pyOpenSSL(self):
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log.debug("_startSSL_pyOpenSSL called")
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tcpsock = self._owner
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# See http://docs.python.org/dev/library/ssl.html
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tcpsock._sslContext = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv3_METHOD)
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tcpsock.ssl_errnum = 0
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tcpsock._sslContext.set_verify(OpenSSL.SSL.VERIFY_PEER,
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self._ssl_verify_callback)
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try:
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tcpsock._sslContext.load_verify_locations(self.cacerts)
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except:
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log.warning('Unable to load SSL certificates from file %s' % \
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os.path.abspath(self.cacerts))
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self._load_user_certs(self.mycerts, tcpsock._sslContext.get_cert_store())
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tcpsock._sslObj = OpenSSL.SSL.Connection(tcpsock._sslContext,
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tcpsock._sock)
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tcpsock._sslObj.set_connect_state() # set to client mode
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wrapper = PyOpenSSLWrapper(tcpsock._sslObj)
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tcpsock._recv = wrapper.recv
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tcpsock._send = wrapper.send
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log.debug("Initiating handshake...")
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tcpsock._sslObj.setblocking(True)
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try:
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tcpsock._sslObj.do_handshake()
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except:
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log.error('Error while TLS handshake: ', exc_info=True)
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return False
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tcpsock._sslObj.setblocking(False)
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self._owner.ssl_lib = PYOPENSSL
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return True
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def _startSSL_stdlib(self):
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log.debug("_startSSL_stdlib called")
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tcpsock=self._owner
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try:
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tcpsock._sock.setblocking(True)
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tcpsock._sslObj = socket.ssl(tcpsock._sock, None, None)
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tcpsock._sock.setblocking(False)
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tcpsock._sslIssuer = tcpsock._sslObj.issuer()
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tcpsock._sslServer = tcpsock._sslObj.server()
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wrapper = StdlibSSLWrapper(tcpsock._sslObj, tcpsock._sock)
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tcpsock._recv = wrapper.recv
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tcpsock._send = wrapper.send
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except:
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log.error("Exception caught in _startSSL_stdlib:", exc_info=True)
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return False
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self._owner.ssl_lib = PYSTDLIB
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return True
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def _ssl_verify_callback(self, sslconn, cert, errnum, depth, ok):
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# Exceptions can't propagate up through this callback, so print them here.
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try:
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self._owner.ssl_fingerprint_sha1 = cert.digest('sha1')
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if errnum == 0:
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return True
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self._owner.ssl_errnum = errnum
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self._owner.ssl_cert_pem = OpenSSL.crypto.dump_certificate(
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OpenSSL.crypto.FILETYPE_PEM, cert)
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return True
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except:
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log.error("Exception caught in _ssl_info_callback:", exc_info=True)
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# Make sure something is printed, even if log is disabled.
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traceback.print_exc()
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# vim: se ts=3:
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