sslutil: don't access message attribute in exception (issue5285)

I should have ran the entire test suite on Python 2.6. Since the
hostname matching tests are implemented in Python (not .t tests),
it didn't uncover this warning. I'm not sure why - warnings should
be printed regardless. This is possibly a bug in the test runner.
But that's for another day...

mercurial/sslutil.py

@@ -1,382 +1,382 b''
 # sslutil.py - SSL handling for mercurial
 #
 # Copyright 2005, 2006, 2007, 2008 Matt Mackall <[e-mail]>
 # Copyright 2006, 2007 Alexis S. L. Carvalho <[e-mail]>
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import os
 import re
 import ssl
 import sys
 
 from .i18n import _
 from . import (
     error,
     util,
 )
 
 # Python 2.7.9+ overhauled the built-in SSL/TLS features of Python. It added
 # support for TLS 1.1, TLS 1.2, SNI, system CA stores, etc. These features are
 # all exposed via the "ssl" module.
 #
 # Depending on the version of Python being used, SSL/TLS support is either
 # modern/secure or legacy/insecure. Many operations in this module have
 # separate code paths depending on support in Python.
 
 hassni = getattr(ssl, 'HAS_SNI', False)
 
 try:
     OP_NO_SSLv2 = ssl.OP_NO_SSLv2
     OP_NO_SSLv3 = ssl.OP_NO_SSLv3
 except AttributeError:
     OP_NO_SSLv2 = 0x1000000
     OP_NO_SSLv3 = 0x2000000
 
 try:
     # ssl.SSLContext was added in 2.7.9 and presence indicates modern
     # SSL/TLS features are available.
     SSLContext = ssl.SSLContext
     modernssl = True
     _canloaddefaultcerts = util.safehasattr(SSLContext, 'load_default_certs')
 except AttributeError:
     modernssl = False
     _canloaddefaultcerts = False
 
     # We implement SSLContext using the interface from the standard library.
     class SSLContext(object):
         # ssl.wrap_socket gained the "ciphers" named argument in 2.7.
         _supportsciphers = sys.version_info >= (2, 7)
 
         def __init__(self, protocol):
             # From the public interface of SSLContext
             self.protocol = protocol
             self.check_hostname = False
             self.options = 0
             self.verify_mode = ssl.CERT_NONE
 
             # Used by our implementation.
             self._certfile = None
             self._keyfile = None
             self._certpassword = None
             self._cacerts = None
             self._ciphers = None
 
         def load_cert_chain(self, certfile, keyfile=None, password=None):
             self._certfile = certfile
             self._keyfile = keyfile
             self._certpassword = password
 
         def load_default_certs(self, purpose=None):
             pass
 
         def load_verify_locations(self, cafile=None, capath=None, cadata=None):
             if capath:
                 raise error.Abort('capath not supported')
             if cadata:
                 raise error.Abort('cadata not supported')
 
             self._cacerts = cafile
 
         def set_ciphers(self, ciphers):
             if not self._supportsciphers:
                 raise error.Abort('setting ciphers not supported')
 
             self._ciphers = ciphers
 
         def wrap_socket(self, socket, server_hostname=None, server_side=False):
             # server_hostname is unique to SSLContext.wrap_socket and is used
             # for SNI in that context. So there's nothing for us to do with it
             # in this legacy code since we don't support SNI.
 
             args = {
                 'keyfile': self._keyfile,
                 'certfile': self._certfile,
                 'server_side': server_side,
                 'cert_reqs': self.verify_mode,
                 'ssl_version': self.protocol,
                 'ca_certs': self._cacerts,
             }
 
             if self._supportsciphers:
                 args['ciphers'] = self._ciphers
 
             return ssl.wrap_socket(socket, **args)
 
 def wrapsocket(sock, keyfile, certfile, ui, cert_reqs=ssl.CERT_NONE,
                ca_certs=None, serverhostname=None):
     """Add SSL/TLS to a socket.
 
     This is a glorified wrapper for ``ssl.wrap_socket()``. It makes sane
     choices based on what security options are available.
 
     In addition to the arguments supported by ``ssl.wrap_socket``, we allow
     the following additional arguments:
 
     * serverhostname - The expected hostname of the remote server. If the
       server (and client) support SNI, this tells the server which certificate
       to use.
     """
     # Despite its name, PROTOCOL_SSLv23 selects the highest protocol
     # that both ends support, including TLS protocols. On legacy stacks,
     # the highest it likely goes in TLS 1.0. On modern stacks, it can
     # support TLS 1.2.
     #
     # The PROTOCOL_TLSv* constants select a specific TLS version
     # only (as opposed to multiple versions). So the method for
     # supporting multiple TLS versions is to use PROTOCOL_SSLv23 and
     # disable protocols via SSLContext.options and OP_NO_* constants.
     # However, SSLContext.options doesn't work unless we have the
     # full/real SSLContext available to us.
     #
     # SSLv2 and SSLv3 are broken. We ban them outright.
     if modernssl:
         protocol = ssl.PROTOCOL_SSLv23
     else:
         protocol = ssl.PROTOCOL_TLSv1
 
     # TODO use ssl.create_default_context() on modernssl.
     sslcontext = SSLContext(protocol)
 
     # This is a no-op on old Python.
     sslcontext.options |= OP_NO_SSLv2 | OP_NO_SSLv3
 
     # This still works on our fake SSLContext.
     sslcontext.verify_mode = cert_reqs
 
     if certfile is not None:
         def password():
             f = keyfile or certfile
             return ui.getpass(_('passphrase for %s: ') % f, '')
         sslcontext.load_cert_chain(certfile, keyfile, password)
 
     if ca_certs is not None:
         sslcontext.load_verify_locations(cafile=ca_certs)
     else:
         # This is a no-op on old Python.
         sslcontext.load_default_certs()
 
     sslsocket = sslcontext.wrap_socket(sock, server_hostname=serverhostname)
     # check if wrap_socket failed silently because socket had been
     # closed
     # - see http://bugs.python.org/issue13721
     if not sslsocket.cipher():
         raise error.Abort(_('ssl connection failed'))
     return sslsocket
 
 class wildcarderror(Exception):
     """Represents an error parsing wildcards in DNS name."""
 
 def _dnsnamematch(dn, hostname, maxwildcards=1):
     """Match DNS names according RFC 6125 section 6.4.3.
 
     This code is effectively copied from CPython's ssl._dnsname_match.
 
     Returns a bool indicating whether the expected hostname matches
     the value in ``dn``.
     """
     pats = []
     if not dn:
         return False
 
     pieces = dn.split(r'.')
     leftmost = pieces[0]
     remainder = pieces[1:]
     wildcards = leftmost.count('*')
     if wildcards > maxwildcards:
         raise wildcarderror(
             _('too many wildcards in certificate DNS name: %s') % dn)
 
     # speed up common case w/o wildcards
     if not wildcards:
         return dn.lower() == hostname.lower()
 
     # RFC 6125, section 6.4.3, subitem 1.
     # The client SHOULD NOT attempt to match a presented identifier in which
     # the wildcard character comprises a label other than the left-most label.
     if leftmost == '*':
         # When '*' is a fragment by itself, it matches a non-empty dotless
         # fragment.
         pats.append('[^.]+')
     elif leftmost.startswith('xn--') or hostname.startswith('xn--'):
         # RFC 6125, section 6.4.3, subitem 3.
         # The client SHOULD NOT attempt to match a presented identifier
         # where the wildcard character is embedded within an A-label or
         # U-label of an internationalized domain name.
         pats.append(re.escape(leftmost))
     else:
         # Otherwise, '*' matches any dotless string, e.g. www*
         pats.append(re.escape(leftmost).replace(r'\*', '[^.]*'))
 
     # add the remaining fragments, ignore any wildcards
     for frag in remainder:
         pats.append(re.escape(frag))
 
     pat = re.compile(r'\A' + r'\.'.join(pats) + r'\Z', re.IGNORECASE)
     return pat.match(hostname) is not None
 
 def _verifycert(cert, hostname):
     '''Verify that cert (in socket.getpeercert() format) matches hostname.
     CRLs is not handled.
 
     Returns error message if any problems are found and None on success.
     '''
     if not cert:
         return _('no certificate received')
 
     dnsnames = []
     san = cert.get('subjectAltName', [])
     for key, value in san:
         if key == 'DNS':
             try:
                 if _dnsnamematch(value, hostname):
                     return
             except wildcarderror as e:
-                return e.message
+                return e.args[0]
 
             dnsnames.append(value)
 
     if not dnsnames:
         # The subject is only checked when there is no DNS in subjectAltName.
         for sub in cert.get('subject', []):
             for key, value in sub:
                 # According to RFC 2818 the most specific Common Name must
                 # be used.
                 if key == 'commonName':
                     # 'subject' entries are unicide.
                     try:
                         value = value.encode('ascii')
                     except UnicodeEncodeError:
                         return _('IDN in certificate not supported')
 
                     try:
                         if _dnsnamematch(value, hostname):
                             return
                     except wildcarderror as e:
-                        return e.message
+                        return e.args[0]
 
                     dnsnames.append(value)
 
     if len(dnsnames) > 1:
         return _('certificate is for %s') % ', '.join(dnsnames)
     elif len(dnsnames) == 1:
         return _('certificate is for %s') % dnsnames[0]
     else:
         return _('no commonName or subjectAltName found in certificate')
 
 
 # CERT_REQUIRED means fetch the cert from the server all the time AND
 # validate it against the CA store provided in web.cacerts.
 
 def _plainapplepython():
     """return true if this seems to be a pure Apple Python that
     * is unfrozen and presumably has the whole mercurial module in the file
       system
     * presumably is an Apple Python that uses Apple OpenSSL which has patches
       for using system certificate store CAs in addition to the provided
       cacerts file
     """
     if sys.platform != 'darwin' or util.mainfrozen() or not sys.executable:
         return False
     exe = os.path.realpath(sys.executable).lower()
     return (exe.startswith('/usr/bin/python') or
             exe.startswith('/system/library/frameworks/python.framework/'))
 
 def _defaultcacerts():
     """return path to CA certificates; None for system's store; ! to disable"""
     if _plainapplepython():
         dummycert = os.path.join(os.path.dirname(__file__), 'dummycert.pem')
         if os.path.exists(dummycert):
             return dummycert
     if _canloaddefaultcerts:
         return None
     return '!'
 
 def sslkwargs(ui, host):
     kws = {'ui': ui}
     hostfingerprint = ui.config('hostfingerprints', host)
     if hostfingerprint:
         return kws
     cacerts = ui.config('web', 'cacerts')
     if cacerts == '!':
         pass
     elif cacerts:
         cacerts = util.expandpath(cacerts)
         if not os.path.exists(cacerts):
             raise error.Abort(_('could not find web.cacerts: %s') % cacerts)
     else:
         cacerts = _defaultcacerts()
         if cacerts and cacerts != '!':
             ui.debug('using %s to enable OS X system CA\n' % cacerts)
         ui.setconfig('web', 'cacerts', cacerts, 'defaultcacerts')
     if cacerts != '!':
         kws.update({'ca_certs': cacerts,
                     'cert_reqs': ssl.CERT_REQUIRED,
                     })
     return kws
 
 class validator(object):
     def __init__(self, ui, host):
         self.ui = ui
         self.host = host
 
     def __call__(self, sock, strict=False):
         host = self.host
 
         if not sock.cipher(): # work around http://bugs.python.org/issue13721
             raise error.Abort(_('%s ssl connection error') % host)
         try:
             peercert = sock.getpeercert(True)
             peercert2 = sock.getpeercert()
         except AttributeError:
             raise error.Abort(_('%s ssl connection error') % host)
 
         if not peercert:
             raise error.Abort(_('%s certificate error: '
                                'no certificate received') % host)
 
         # If a certificate fingerprint is pinned, use it and only it to
         # validate the remote cert.
         hostfingerprints = self.ui.configlist('hostfingerprints', host)
         peerfingerprint = util.sha1(peercert).hexdigest()
         nicefingerprint = ":".join([peerfingerprint[x:x + 2]
             for x in xrange(0, len(peerfingerprint), 2)])
         if hostfingerprints:
             fingerprintmatch = False
             for hostfingerprint in hostfingerprints:
                 if peerfingerprint.lower() == \
                         hostfingerprint.replace(':', '').lower():
                     fingerprintmatch = True
                     break
             if not fingerprintmatch:
                 raise error.Abort(_('certificate for %s has unexpected '
                                    'fingerprint %s') % (host, nicefingerprint),
                                  hint=_('check hostfingerprint configuration'))
             self.ui.debug('%s certificate matched fingerprint %s\n' %
                           (host, nicefingerprint))
             return
 
         # No pinned fingerprint. Establish trust by looking at the CAs.
         cacerts = self.ui.config('web', 'cacerts')
         if cacerts != '!':
             msg = _verifycert(peercert2, host)
             if msg:
                 raise error.Abort(_('%s certificate error: %s') % (host, msg),
                                  hint=_('configure hostfingerprint %s or use '
                                         '--insecure to connect insecurely') %
                                       nicefingerprint)
             self.ui.debug('%s certificate successfully verified\n' % host)
         elif strict:
             raise error.Abort(_('%s certificate with fingerprint %s not '
                                'verified') % (host, nicefingerprint),
                              hint=_('check hostfingerprints or web.cacerts '
                                      'config setting'))
         else:
             self.ui.warn(_('warning: %s certificate with fingerprint %s not '
                            'verified (check hostfingerprints or web.cacerts '
                            'config setting)\n') %
                          (host, nicefingerprint))