python-urllib3/Unbundle-ssl_match_hostname-backport.patch

From ee3425b5bfba3262c3485265c3aaaf99169e11d0 Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jcline@redhat.com>
Date: Mon, 29 Oct 2018 16:07:52 -0400
Subject: [PATCH] Unbundle ssl_match_hostname backport

Fedora has shipped 3.5+ for a long time and we depend on backports of
Python 2.

Signed-off-by: Jeremy Cline <jcline@redhat.com>
---
 .../packages/ssl_match_hostname/__init__.py   |  14 +-
 .../ssl_match_hostname/_implementation.py     | 156 ------------------
 2 files changed, 3 insertions(+), 167 deletions(-)
 delete mode 100644 src/urllib3/packages/ssl_match_hostname/_implementation.py

diff --git a/src/urllib3/packages/ssl_match_hostname/__init__.py b/src/urllib3/packages/ssl_match_hostname/__init__.py
index d6594eb..6bd8fb9 100644
--- a/src/urllib3/packages/ssl_match_hostname/__init__.py
+++ b/src/urllib3/packages/ssl_match_hostname/__init__.py
@@ -1,19 +1,11 @@
 import sys
 
 try:
-    # Our match_hostname function is the same as 3.5's, so we only want to
-    # import the match_hostname function if it's at least that good.
-    if sys.version_info < (3, 5):
-        raise ImportError("Fallback to vendored code")
-
+    # Python 3.5+
     from ssl import CertificateError, match_hostname
 except ImportError:
-    try:
-        # Backport of the function from a pypi module
-        from backports.ssl_match_hostname import CertificateError, match_hostname
-    except ImportError:
-        # Our vendored copy
-        from ._implementation import CertificateError, match_hostname
+    # Python 2
+    from backports.ssl_match_hostname import CertificateError, match_hostname
 
 # Not needed, but documenting what we provide.
 __all__ = ('CertificateError', 'match_hostname')
diff --git a/src/urllib3/packages/ssl_match_hostname/_implementation.py b/src/urllib3/packages/ssl_match_hostname/_implementation.py
deleted file mode 100644
index d6e66c0..0000000
--- a/src/urllib3/packages/ssl_match_hostname/_implementation.py
+++ /dev/null
@@ -1,156 +0,0 @@
-"""The match_hostname() function from Python 3.3.3, essential when using SSL."""
-
-# Note: This file is under the PSF license as the code comes from the python
-# stdlib.   http://docs.python.org/3/license.html
-
-import re
-import sys
-
-# ipaddress has been backported to 2.6+ in pypi.  If it is installed on the
-# system, use it to handle IPAddress ServerAltnames (this was added in
-# python-3.5) otherwise only do DNS matching.  This allows
-# backports.ssl_match_hostname to continue to be used in Python 2.7.
-try:
-    import ipaddress
-except ImportError:
-    ipaddress = None
-
-__version__ = '3.5.0.1'
-
-
-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
-
-    # Ported from python3-syntax:
-    # leftmost, *remainder = dn.split(r'.')
-    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 _to_unicode(obj):
-    if isinstance(obj, str) and sys.version_info < (3,):
-        obj = unicode(obj, encoding='ascii', errors='strict')
-    return obj
-
-def _ipaddress_match(ipname, host_ip):
-    """Exact matching of IP addresses.
-
-    RFC 6125 explicitly doesn't define an algorithm for this
-    (section 1.7.2 - "Out of Scope").
-    """
-    # OpenSSL may add a trailing newline to a subjectAltName's IP address
-    # Divergence from upstream: ipaddress can't handle byte str
-    ip = ipaddress.ip_address(_to_unicode(ipname).rstrip())
-    return ip == host_ip
-
-
-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, match_hostname needs a "
-                         "SSL socket or SSL context with either "
-                         "CERT_OPTIONAL or CERT_REQUIRED")
-    try:
-        # Divergence from upstream: ipaddress can't handle byte str
-        host_ip = ipaddress.ip_address(_to_unicode(hostname))
-    except ValueError:
-        # Not an IP address (common case)
-        host_ip = None
-    except UnicodeError:
-        # Divergence from upstream: Have to deal with ipaddress not taking
-        # byte strings.  addresses should be all ascii, so we consider it not
-        # an ipaddress in this case
-        host_ip = None
-    except AttributeError:
-        # Divergence from upstream: Make ipaddress library optional
-        if ipaddress is None:
-            host_ip = None
-        else:
-            raise
-    dnsnames = []
-    san = cert.get('subjectAltName', ())
-    for key, value in san:
-        if key == 'DNS':
-            if host_ip is None and _dnsname_match(value, hostname):
-                return
-            dnsnames.append(value)
-        elif key == 'IP Address':
-            if host_ip is not None and _ipaddress_match(value, host_ip):
-                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")
-- 
2.19.1