url: verify correctness of https server certificates (issue2407)

Pythons SSL module verifies that certificates received for HTTPS are valid
according to the specified cacerts, but it doesn't verify that the certificate
is for the host we connect to.

We now explicitly verify that the commonName in the received certificate
matches the requested hostname and is valid for the time being.

This is a minimal patch where we try to fail to the safe side, but we do still
rely on Python's SSL functionality and do not try to implement the standards
fully and correctly. CRLs and subjectAltName are not handled and proxies
haven't been considered.

This change might break connections to some sites if cacerts is specified and
the certificates (by our definition) isn't correct. The workaround is to
disable cacerts which in most cases isn't much worse than it was before with
cacerts.

tests/test-url.py

@@ -0,0 +1,41 b''
+#!/usr/bin/env python
+
+def check(a, b):
+    if a != b:
+        print (a, b)
+
+from mercurial.url import _verifycert
+
+# Test non-wildcard certificates        
+check(_verifycert({'subject': ((('commonName', 'example.com'),),)}, 'example.com'),
+    None)
+check(_verifycert({'subject': ((('commonName', 'example.com'),),)}, 'www.example.com'),
+    'certificate is for example.com')
+check(_verifycert({'subject': ((('commonName', 'www.example.com'),),)}, 'example.com'),
+    'certificate is for www.example.com')
+
+# Test wildcard certificates
+check(_verifycert({'subject': ((('commonName', '*.example.com'),),)}, 'www.example.com'),
+    None)
+check(_verifycert({'subject': ((('commonName', '*.example.com'),),)}, 'example.com'),
+    'certificate is for *.example.com')
+check(_verifycert({'subject': ((('commonName', '*.example.com'),),)}, 'w.w.example.com'),
+    'certificate is for *.example.com')
+
+# Avoid some pitfalls
+check(_verifycert({'subject': ((('commonName', '*.foo'),),)}, 'foo'),
+    'certificate is for *.foo')
+check(_verifycert({'subject': ((('commonName', '*o'),),)}, 'foo'),
+    'certificate is for *o')
+
+import time
+lastyear = time.gmtime().tm_year - 1
+nextyear = time.gmtime().tm_year + 1
+check(_verifycert({'notAfter': 'May  9 00:00:00 %s GMT' % lastyear}, 'example.com'),
+    'certificate expired May  9 00:00:00 %s GMT' % lastyear)
+check(_verifycert({'notBefore': 'May  9 00:00:00 %s GMT' % nextyear}, 'example.com'),
+    'certificate not valid before May  9 00:00:00 %s GMT' % nextyear)
+check(_verifycert({'notAfter': 'Sep 29 15:29:48 %s GMT' % nextyear, 'subject': ()}, 'example.com'),
+    'no commonName found in certificate')
+check(_verifycert(None, 'example.com'),
+    'no certificate received')

mercurial/url.py

@@ -1,657 +1,686 b''
 # url.py - HTTP 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.
 
-import urllib, urllib2, urlparse, httplib, os, re, socket, cStringIO
+import urllib, urllib2, urlparse, httplib, os, re, socket, cStringIO, time
 from i18n import _
 import keepalive, util
 
 def _urlunparse(scheme, netloc, path, params, query, fragment, url):
     '''Handle cases where urlunparse(urlparse(x://)) doesn't preserve the "//"'''
     result = urlparse.urlunparse((scheme, netloc, path, params, query, fragment))
     if (scheme and
         result.startswith(scheme + ':') and
         not result.startswith(scheme + '://') and
         url.startswith(scheme + '://')
        ):
         result = scheme + '://' + result[len(scheme + ':'):]
     return result
 
 def hidepassword(url):
     '''hide user credential in a url string'''
     scheme, netloc, path, params, query, fragment = urlparse.urlparse(url)
     netloc = re.sub('([^:]*):([^@]*)@(.*)', r'\1:***@\3', netloc)
     return _urlunparse(scheme, netloc, path, params, query, fragment, url)
 
 def removeauth(url):
     '''remove all authentication information from a url string'''
     scheme, netloc, path, params, query, fragment = urlparse.urlparse(url)
     netloc = netloc[netloc.find('@')+1:]
     return _urlunparse(scheme, netloc, path, params, query, fragment, url)
 
 def netlocsplit(netloc):
     '''split [user[:passwd]@]host[:port] into 4-tuple.'''
 
     a = netloc.find('@')
     if a == -1:
         user, passwd = None, None
     else:
         userpass, netloc = netloc[:a], netloc[a + 1:]
         c = userpass.find(':')
         if c == -1:
             user, passwd = urllib.unquote(userpass), None
         else:
             user = urllib.unquote(userpass[:c])
             passwd = urllib.unquote(userpass[c + 1:])
     c = netloc.find(':')
     if c == -1:
         host, port = netloc, None
     else:
         host, port = netloc[:c], netloc[c + 1:]
     return host, port, user, passwd
 
 def netlocunsplit(host, port, user=None, passwd=None):
     '''turn host, port, user, passwd into [user[:passwd]@]host[:port].'''
     if port:
         hostport = host + ':' + port
     else:
         hostport = host
     if user:
         quote = lambda s: urllib.quote(s, safe='')
         if passwd:
             userpass = quote(user) + ':' + quote(passwd)
         else:
             userpass = quote(user)
         return userpass + '@' + hostport
     return hostport
 
 _safe = ('abcdefghijklmnopqrstuvwxyz'
          'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
          '0123456789' '_.-/')
 _safeset = None
 _hex = None
 def quotepath(path):
     '''quote the path part of a URL
 
     This is similar to urllib.quote, but it also tries to avoid
     quoting things twice (inspired by wget):
 
     >>> quotepath('abc def')
     'abc%20def'
     >>> quotepath('abc%20def')
     'abc%20def'
     >>> quotepath('abc%20 def')
     'abc%20%20def'
     >>> quotepath('abc def%20')
     'abc%20def%20'
     >>> quotepath('abc def%2')
     'abc%20def%252'
     >>> quotepath('abc def%')
     'abc%20def%25'
     '''
     global _safeset, _hex
     if _safeset is None:
         _safeset = set(_safe)
         _hex = set('abcdefABCDEF0123456789')
     l = list(path)
     for i in xrange(len(l)):
         c = l[i]
         if (c == '%' and i + 2 < len(l) and
             l[i + 1] in _hex and l[i + 2] in _hex):
             pass
         elif c not in _safeset:
             l[i] = '%%%02X' % ord(c)
     return ''.join(l)
 
 class passwordmgr(urllib2.HTTPPasswordMgrWithDefaultRealm):
     def __init__(self, ui):
         urllib2.HTTPPasswordMgrWithDefaultRealm.__init__(self)
         self.ui = ui
 
     def find_user_password(self, realm, authuri):
         authinfo = urllib2.HTTPPasswordMgrWithDefaultRealm.find_user_password(
             self, realm, authuri)
         user, passwd = authinfo
         if user and passwd:
             self._writedebug(user, passwd)
             return (user, passwd)
 
         if not user:
             auth = self.readauthtoken(authuri)
             if auth:
                 user, passwd = auth.get('username'), auth.get('password')
         if not user or not passwd:
             if not self.ui.interactive():
                 raise util.Abort(_('http authorization required'))
 
             self.ui.write(_("http authorization required\n"))
             self.ui.status(_("realm: %s\n") % realm)
             if user:
                 self.ui.status(_("user: %s\n") % user)
             else:
                 user = self.ui.prompt(_("user:"), default=None)
 
             if not passwd:
                 passwd = self.ui.getpass()
 
         self.add_password(realm, authuri, user, passwd)
         self._writedebug(user, passwd)
         return (user, passwd)
 
     def _writedebug(self, user, passwd):
         msg = _('http auth: user %s, password %s\n')
         self.ui.debug(msg % (user, passwd and '*' * len(passwd) or 'not set'))
 
     def readauthtoken(self, uri):
         # Read configuration
         config = dict()
         for key, val in self.ui.configitems('auth'):
             if '.' not in key:
                 self.ui.warn(_("ignoring invalid [auth] key '%s'\n") % key)
                 continue
             group, setting = key.split('.', 1)
             gdict = config.setdefault(group, dict())
             if setting in ('username', 'cert', 'key'):
                 val = util.expandpath(val)
             gdict[setting] = val
 
         # Find the best match
         scheme, hostpath = uri.split('://', 1)
         bestlen = 0
         bestauth = None
         for auth in config.itervalues():
             prefix = auth.get('prefix')
             if not prefix:
                 continue
             p = prefix.split('://', 1)
             if len(p) > 1:
                 schemes, prefix = [p[0]], p[1]
             else:
                 schemes = (auth.get('schemes') or 'https').split()
             if (prefix == '*' or hostpath.startswith(prefix)) and \
                 len(prefix) > bestlen and scheme in schemes:
                 bestlen = len(prefix)
                 bestauth = auth
         return bestauth
 
 class proxyhandler(urllib2.ProxyHandler):
     def __init__(self, ui):
         proxyurl = ui.config("http_proxy", "host") or os.getenv('http_proxy')
         # XXX proxyauthinfo = None
 
         if proxyurl:
             # proxy can be proper url or host[:port]
             if not (proxyurl.startswith('http:') or
                     proxyurl.startswith('https:')):
                 proxyurl = 'http://' + proxyurl + '/'
             snpqf = urlparse.urlsplit(proxyurl)
             proxyscheme, proxynetloc, proxypath, proxyquery, proxyfrag = snpqf
             hpup = netlocsplit(proxynetloc)
 
             proxyhost, proxyport, proxyuser, proxypasswd = hpup
             if not proxyuser:
                 proxyuser = ui.config("http_proxy", "user")
                 proxypasswd = ui.config("http_proxy", "passwd")
 
             # see if we should use a proxy for this url
             no_list = ["localhost", "127.0.0.1"]
             no_list.extend([p.lower() for
                             p in ui.configlist("http_proxy", "no")])
             no_list.extend([p.strip().lower() for
                             p in os.getenv("no_proxy", '').split(',')
                             if p.strip()])
             # "http_proxy.always" config is for running tests on localhost
             if ui.configbool("http_proxy", "always"):
                 self.no_list = []
             else:
                 self.no_list = no_list
 
             proxyurl = urlparse.urlunsplit((
                 proxyscheme, netlocunsplit(proxyhost, proxyport,
                                                 proxyuser, proxypasswd or ''),
                 proxypath, proxyquery, proxyfrag))
             proxies = {'http': proxyurl, 'https': proxyurl}
             ui.debug('proxying through http://%s:%s\n' %
                       (proxyhost, proxyport))
         else:
             proxies = {}
 
         # urllib2 takes proxy values from the environment and those
         # will take precedence if found, so drop them
         for env in ["HTTP_PROXY", "http_proxy", "no_proxy"]:
             try:
                 if env in os.environ:
                     del os.environ[env]
             except OSError:
                 pass
 
         urllib2.ProxyHandler.__init__(self, proxies)
         self.ui = ui
 
     def proxy_open(self, req, proxy, type_):
         host = req.get_host().split(':')[0]
         if host in self.no_list:
             return None
 
         # work around a bug in Python < 2.4.2
         # (it leaves a "\n" at the end of Proxy-authorization headers)
         baseclass = req.__class__
         class _request(baseclass):
             def add_header(self, key, val):
                 if key.lower() == 'proxy-authorization':
                     val = val.strip()
                 return baseclass.add_header(self, key, val)
         req.__class__ = _request
 
         return urllib2.ProxyHandler.proxy_open(self, req, proxy, type_)
 
 class httpsendfile(file):
     def __len__(self):
         return os.fstat(self.fileno()).st_size
 
 def _gen_sendfile(connection):
     def _sendfile(self, data):
         # send a file
         if isinstance(data, httpsendfile):
             # if auth required, some data sent twice, so rewind here
             data.seek(0)
             for chunk in util.filechunkiter(data):
                 connection.send(self, chunk)
         else:
             connection.send(self, data)
     return _sendfile
 
 has_https = hasattr(urllib2, 'HTTPSHandler')
 if has_https:
     try:
         # avoid using deprecated/broken FakeSocket in python 2.6
         import ssl
         _ssl_wrap_socket = ssl.wrap_socket
         CERT_REQUIRED = ssl.CERT_REQUIRED
     except ImportError:
         CERT_REQUIRED = 2
 
         def _ssl_wrap_socket(sock, key_file, cert_file,
                              cert_reqs=CERT_REQUIRED, ca_certs=None):
             if ca_certs:
                 raise util.Abort(_(
                     'certificate checking requires Python 2.6'))
 
             ssl = socket.ssl(sock, key_file, cert_file)
             return httplib.FakeSocket(sock, ssl)
 
     try:
         _create_connection = socket.create_connection
     except AttributeError:
         _GLOBAL_DEFAULT_TIMEOUT = object()
 
         def _create_connection(address, timeout=_GLOBAL_DEFAULT_TIMEOUT,
                                source_address=None):
             # lifted from Python 2.6
 
             msg = "getaddrinfo returns an empty list"
             host, port = address
             for res in socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM):
                 af, socktype, proto, canonname, sa = res
                 sock = None
                 try:
                     sock = socket.socket(af, socktype, proto)
                     if timeout is not _GLOBAL_DEFAULT_TIMEOUT:
                         sock.settimeout(timeout)
                     if source_address:
                         sock.bind(source_address)
                     sock.connect(sa)
                     return sock
 
                 except socket.error, msg:
                     if sock is not None:
                         sock.close()
 
             raise socket.error, msg
 
 class httpconnection(keepalive.HTTPConnection):
     # must be able to send big bundle as stream.
     send = _gen_sendfile(keepalive.HTTPConnection)
 
     def connect(self):
         if has_https and self.realhostport: # use CONNECT proxy
             self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
             self.sock.connect((self.host, self.port))
             if _generic_proxytunnel(self):
                 # we do not support client x509 certificates
                 self.sock = _ssl_wrap_socket(self.sock, None, None)
         else:
             keepalive.HTTPConnection.connect(self)
 
     def getresponse(self):
         proxyres = getattr(self, 'proxyres', None)
         if proxyres:
             if proxyres.will_close:
                 self.close()
             self.proxyres = None
             return proxyres
         return keepalive.HTTPConnection.getresponse(self)
 
 # general transaction handler to support different ways to handle
 # HTTPS proxying before and after Python 2.6.3.
 def _generic_start_transaction(handler, h, req):
     if hasattr(req, '_tunnel_host') and req._tunnel_host:
         tunnel_host = req._tunnel_host
         if tunnel_host[:7] not in ['http://', 'https:/']:
             tunnel_host = 'https://' + tunnel_host
         new_tunnel = True
     else:
         tunnel_host = req.get_selector()
         new_tunnel = False
 
     if new_tunnel or tunnel_host == req.get_full_url(): # has proxy
         urlparts = urlparse.urlparse(tunnel_host)
         if new_tunnel or urlparts[0] == 'https': # only use CONNECT for HTTPS
             realhostport = urlparts[1]
             if realhostport[-1] == ']' or ':' not in realhostport:
                 realhostport += ':443'
 
             h.realhostport = realhostport
             h.headers = req.headers.copy()
             h.headers.update(handler.parent.addheaders)
             return
 
     h.realhostport = None
     h.headers = None
 
 def _generic_proxytunnel(self):
     proxyheaders = dict(
             [(x, self.headers[x]) for x in self.headers
              if x.lower().startswith('proxy-')])
     self._set_hostport(self.host, self.port)
     self.send('CONNECT %s HTTP/1.0\r\n' % self.realhostport)
     for header in proxyheaders.iteritems():
         self.send('%s: %s\r\n' % header)
     self.send('\r\n')
 
     # majority of the following code is duplicated from
     # httplib.HTTPConnection as there are no adequate places to
     # override functions to provide the needed functionality
     res = self.response_class(self.sock,
                               strict=self.strict,
                               method=self._method)
 
     while True:
         version, status, reason = res._read_status()
         if status != httplib.CONTINUE:
             break
         while True:
             skip = res.fp.readline().strip()
             if not skip:
                 break
     res.status = status
     res.reason = reason.strip()
 
     if res.status == 200:
         while True:
             line = res.fp.readline()
             if line == '\r\n':
                 break
         return True
 
     if version == 'HTTP/1.0':
         res.version = 10
     elif version.startswith('HTTP/1.'):
         res.version = 11
     elif version == 'HTTP/0.9':
         res.version = 9
     else:
         raise httplib.UnknownProtocol(version)
 
     if res.version == 9:
         res.length = None
         res.chunked = 0
         res.will_close = 1
         res.msg = httplib.HTTPMessage(cStringIO.StringIO())
         return False
 
     res.msg = httplib.HTTPMessage(res.fp)
     res.msg.fp = None
 
     # are we using the chunked-style of transfer encoding?
     trenc = res.msg.getheader('transfer-encoding')
     if trenc and trenc.lower() == "chunked":
         res.chunked = 1
         res.chunk_left = None
     else:
         res.chunked = 0
 
     # will the connection close at the end of the response?
     res.will_close = res._check_close()
 
     # do we have a Content-Length?
     # NOTE: RFC 2616, S4.4, #3 says we ignore this if tr_enc is "chunked"
     length = res.msg.getheader('content-length')
     if length and not res.chunked:
         try:
             res.length = int(length)
         except ValueError:
             res.length = None
         else:
             if res.length < 0:  # ignore nonsensical negative lengths
                 res.length = None
     else:
         res.length = None
 
     # does the body have a fixed length? (of zero)
     if (status == httplib.NO_CONTENT or status == httplib.NOT_MODIFIED or
         100 <= status < 200 or # 1xx codes
         res._method == 'HEAD'):
         res.length = 0
 
     # if the connection remains open, and we aren't using chunked, and
     # a content-length was not provided, then assume that the connection
     # WILL close.
     if (not res.will_close and
        not res.chunked and
        res.length is None):
         res.will_close = 1
 
     self.proxyres = res
 
     return False
 
 class httphandler(keepalive.HTTPHandler):
     def http_open(self, req):
         return self.do_open(httpconnection, req)
 
     def _start_transaction(self, h, req):
         _generic_start_transaction(self, h, req)
         return keepalive.HTTPHandler._start_transaction(self, h, req)
 
+def _verifycert(cert, hostname):
+    '''Verify that cert (in socket.getpeercert() format) matches hostname and is 
+    valid at this time. CRLs and subjectAltName are not handled.
+    
+    Returns error message if any problems are found and None on success.
+    '''
+    if not cert:
+        return _('no certificate received')
+    notafter = cert.get('notAfter')
+    if notafter and time.time() > ssl.cert_time_to_seconds(notafter):
+        return _('certificate expired %s') % notafter
+    notbefore = cert.get('notBefore')
+    if notbefore and time.time() < ssl.cert_time_to_seconds(notbefore):
+        return _('certificate not valid before %s') % notbefore
+    dnsname = hostname.lower()
+    for s in cert.get('subject', []):
+        key, value = s[0]
+        if key == 'commonName':
+            certname = value.lower()
+            if (certname == dnsname or
+                '.' in dnsname and certname == '*.' + dnsname.split('.', 1)[1]):
+                return None
+            return _('certificate is for %s') % certname
+    return _('no commonName found in certificate')
+
 if has_https:
     class BetterHTTPS(httplib.HTTPSConnection):
         send = keepalive.safesend
 
         def connect(self):
             if hasattr(self, 'ui'):
                 cacerts = self.ui.config('web', 'cacerts')
             else:
                 cacerts = None
 
             if cacerts:
                 sock = _create_connection((self.host, self.port))
                 self.sock = _ssl_wrap_socket(sock, self.key_file,
                         self.cert_file, cert_reqs=CERT_REQUIRED,
                         ca_certs=cacerts)
-                self.ui.debug(_('server identity verification succeeded\n'))
+                msg = _verifycert(self.sock.getpeercert(), self.host)
+                if msg:
+                    raise util.Abort('%s certificate error: %s' % (self.host, msg))
+                self.ui.debug(_('%s certificate successfully verified\n') % 
+                    self.host)
             else:
                 httplib.HTTPSConnection.connect(self)
 
     class httpsconnection(BetterHTTPS):
         response_class = keepalive.HTTPResponse
         # must be able to send big bundle as stream.
         send = _gen_sendfile(BetterHTTPS)
         getresponse = keepalive.wrapgetresponse(httplib.HTTPSConnection)
 
         def connect(self):
             if self.realhostport: # use CONNECT proxy
                 self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                 self.sock.connect((self.host, self.port))
                 if _generic_proxytunnel(self):
                     self.sock = _ssl_wrap_socket(self.sock, self.cert_file,
                                                  self.key_file)
             else:
                 BetterHTTPS.connect(self)
 
     class httpshandler(keepalive.KeepAliveHandler, urllib2.HTTPSHandler):
         def __init__(self, ui):
             keepalive.KeepAliveHandler.__init__(self)
             urllib2.HTTPSHandler.__init__(self)
             self.ui = ui
             self.pwmgr = passwordmgr(self.ui)
 
         def _start_transaction(self, h, req):
             _generic_start_transaction(self, h, req)
             return keepalive.KeepAliveHandler._start_transaction(self, h, req)
 
         def https_open(self, req):
             self.auth = self.pwmgr.readauthtoken(req.get_full_url())
             return self.do_open(self._makeconnection, req)
 
         def _makeconnection(self, host, port=None, *args, **kwargs):
             keyfile = None
             certfile = None
 
             if len(args) >= 1: # key_file
                 keyfile = args[0]
             if len(args) >= 2: # cert_file
                 certfile = args[1]
             args = args[2:]
 
             # if the user has specified different key/cert files in
             # hgrc, we prefer these
             if self.auth and 'key' in self.auth and 'cert' in self.auth:
                 keyfile = self.auth['key']
                 certfile = self.auth['cert']
 
             conn = httpsconnection(host, port, keyfile, certfile, *args, **kwargs)
             conn.ui = self.ui
             return conn
 
 class httpdigestauthhandler(urllib2.HTTPDigestAuthHandler):
     def __init__(self, *args, **kwargs):
         urllib2.HTTPDigestAuthHandler.__init__(self, *args, **kwargs)
         self.retried_req = None
 
     def reset_retry_count(self):
         # Python 2.6.5 will call this on 401 or 407 errors and thus loop
         # forever. We disable reset_retry_count completely and reset in
         # http_error_auth_reqed instead.
         pass
 
     def http_error_auth_reqed(self, auth_header, host, req, headers):
         # Reset the retry counter once for each request.
         if req is not self.retried_req:
             self.retried_req = req
             self.retried = 0
         # In python < 2.5 AbstractDigestAuthHandler raises a ValueError if
         # it doesn't know about the auth type requested. This can happen if
         # somebody is using BasicAuth and types a bad password.
         try:
             return urllib2.HTTPDigestAuthHandler.http_error_auth_reqed(
                         self, auth_header, host, req, headers)
         except ValueError, inst:
             arg = inst.args[0]
             if arg.startswith("AbstractDigestAuthHandler doesn't know "):
                 return
             raise
 
 class httpbasicauthhandler(urllib2.HTTPBasicAuthHandler):
     def __init__(self, *args, **kwargs):
         urllib2.HTTPBasicAuthHandler.__init__(self, *args, **kwargs)
         self.retried_req = None
 
     def reset_retry_count(self):
         # Python 2.6.5 will call this on 401 or 407 errors and thus loop
         # forever. We disable reset_retry_count completely and reset in
         # http_error_auth_reqed instead.
         pass
 
     def http_error_auth_reqed(self, auth_header, host, req, headers):
         # Reset the retry counter once for each request.
         if req is not self.retried_req:
             self.retried_req = req
             self.retried = 0
         return urllib2.HTTPBasicAuthHandler.http_error_auth_reqed(
                         self, auth_header, host, req, headers)
 
 def getauthinfo(path):
     scheme, netloc, urlpath, query, frag = urlparse.urlsplit(path)
     if not urlpath:
         urlpath = '/'
     if scheme != 'file':
         # XXX: why are we quoting the path again with some smart
         # heuristic here? Anyway, it cannot be done with file://
         # urls since path encoding is os/fs dependent (see
         # urllib.pathname2url() for details).
         urlpath = quotepath(urlpath)
     host, port, user, passwd = netlocsplit(netloc)
 
     # urllib cannot handle URLs with embedded user or passwd
     url = urlparse.urlunsplit((scheme, netlocunsplit(host, port),
                               urlpath, query, frag))
     if user:
         netloc = host
         if port:
             netloc += ':' + port
         # Python < 2.4.3 uses only the netloc to search for a password
         authinfo = (None, (url, netloc), user, passwd or '')
     else:
         authinfo = None
     return url, authinfo
 
 handlerfuncs = []
 
 def opener(ui, authinfo=None):
     '''
     construct an opener suitable for urllib2
     authinfo will be added to the password manager
     '''
     handlers = [httphandler()]
     if has_https:
         handlers.append(httpshandler(ui))
 
     handlers.append(proxyhandler(ui))
 
     passmgr = passwordmgr(ui)
     if authinfo is not None:
         passmgr.add_password(*authinfo)
         user, passwd = authinfo[2:4]
         ui.debug('http auth: user %s, password %s\n' %
                  (user, passwd and '*' * len(passwd) or 'not set'))
 
     handlers.extend((httpbasicauthhandler(passmgr),
                      httpdigestauthhandler(passmgr)))
     handlers.extend([h(ui, passmgr) for h in handlerfuncs])
     opener = urllib2.build_opener(*handlers)
 
     # 1.0 here is the _protocol_ version
     opener.addheaders = [('User-agent', 'mercurial/proto-1.0')]
     opener.addheaders.append(('Accept', 'application/mercurial-0.1'))
     return opener
 
 scheme_re = re.compile(r'^([a-zA-Z0-9+-.]+)://')
 
 def open(ui, url, data=None):
     scheme = None
     m = scheme_re.search(url)
     if m:
         scheme = m.group(1).lower()
     if not scheme:
         path = util.normpath(os.path.abspath(url))
         url = 'file://' + urllib.pathname2url(path)
         authinfo = None
     else:
         url, authinfo = getauthinfo(url)
     return opener(ui, authinfo).open(url, data)