From e6adec8cae7c4a7840fb012c6479856caaf18aba Mon Sep 17 00:00:00 2001
From: Randy Barlow <bowlofeggs@electronsweatshop.com>
Date: Fri, 15 Jul 2016 10:12:16 -0400
Subject: [PATCH] Use ssl.match_hostname from the Python stdlib.

This patch removes the bundled ssl.match_hostname library as it was
vulnerable to CVE-2013-7440 and CVE-2013-2099, and wasn't needed
anyway since Fedora >= 22 has the needed module in the Python
standard library. It also adjusts imports so that they exclusively
use the code from Python.
---
 pymongo/errors.py             |   5 +--
 pymongo/pool.py               |   6 +--
 pymongo/ssl_match_hostname.py | 100 ------------------------------------------
 3 files changed, 2 insertions(+), 109 deletions(-)
 delete mode 100644 pymongo/ssl_match_hostname.py

diff --git a/pymongo/errors.py b/pymongo/errors.py
index fb4c9e4..e8e6350 100644
--- a/pymongo/errors.py
+++ b/pymongo/errors.py
@@ -16,10 +16,7 @@
 
 from bson.errors import *
 
-try:
-    from ssl import CertificateError
-except ImportError:
-    from pymongo.ssl_match_hostname import CertificateError
+from ssl import CertificateError
 
 
 class PyMongoError(Exception):
diff --git a/pymongo/pool.py b/pymongo/pool.py
index 6e9cc75..41bef83 100644
--- a/pymongo/pool.py
+++ b/pymongo/pool.py
@@ -44,11 +44,7 @@ from pymongo.server_type import SERVER_TYPE
 # main thread, to avoid the deadlock. See PYTHON-607.
 u'foo'.encode('idna')
 
-try:
-    from ssl import match_hostname, CertificateError
-except ImportError:
-    # These don't require the ssl module
-    from pymongo.ssl_match_hostname import match_hostname, CertificateError
+from ssl import match_hostname, CertificateError
 
 
 def _raise_connection_failure(address, error):
diff --git a/pymongo/ssl_match_hostname.py b/pymongo/ssl_match_hostname.py
deleted file mode 100644
index f74df15..0000000
--- a/pymongo/ssl_match_hostname.py
+++ /dev/null
@@ -1,100 +0,0 @@
-# Backport of the match_hostname logic introduced in python 3.2
-# http://hg.python.org/releasing/3.3.5/file/993955b807b3/Lib/ssl.py
-
-import re
-
-
-class CertificateError(ValueError):
-    pass
-
-
-def _dnsname_match(dn, hostname, max_wildcards=1):
-    """Matching according to RFC 6125, section 6.4.3
-
-    http://tools.ietf.org/html/rfc6125#section-6.4.3
-    """
-    pats = []
-    if not dn:
-        return False
-
-    parts = dn.split(r'.')
-    leftmost = parts[0]
-    remainder = parts[1:]
-
-    wildcards = leftmost.count('*')
-    if wildcards > max_wildcards:
-        # Issue #17980: avoid denials of service by refusing more
-        # than one wildcard per fragment.  A survey of established
-        # policy among SSL implementations showed it to be a
-        # reasonable choice.
-        raise CertificateError(
-            "too many wildcards in certificate DNS name: " + repr(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)
-
-
-def match_hostname(cert, hostname):
-    """Verify that *cert* (in decoded format as returned by
-    SSLSocket.getpeercert()) matches the *hostname*.  RFC 2818 and RFC 6125
-    rules are followed, but IP addresses are not accepted for *hostname*.
-
-    CertificateError is raised on failure. On success, the function
-    returns nothing.
-    """
-    if not cert:
-        raise ValueError("empty or no certificate")
-    dnsnames = []
-    san = cert.get('subjectAltName', ())
-    for key, value in san:
-        if key == 'DNS':
-            if _dnsname_match(value, hostname):
-                return
-            dnsnames.append(value)
-    if not dnsnames:
-        # The subject is only checked when there is no dNSName entry
-        # in subjectAltName
-        for sub in cert.get('subject', ()):
-            for key, value in sub:
-                # XXX according to RFC 2818, the most specific Common Name
-                # must be used.
-                if key == 'commonName':
-                    if _dnsname_match(value, hostname):
-                        return
-                    dnsnames.append(value)
-    if len(dnsnames) > 1:
-        raise CertificateError("hostname %r "
-            "doesn't match either of %s"
-            % (hostname, ', '.join(map(repr, dnsnames))))
-    elif len(dnsnames) == 1:
-        raise CertificateError("hostname %r "
-            "doesn't match %r"
-            % (hostname, dnsnames[0]))
-    else:
-        raise CertificateError("no appropriate commonName or "
-            "subjectAltName fields were found")
-- 
2.9.0