[python3/f19] Change behavior of ssl.match_hostname() to follow RFC 6125 (rhbz#1023742)
Matej Stuchlik
mstuchli at fedoraproject.org
Fri Nov 8 13:31:10 UTC 2013
commit 92d5ecc93bd61eded7f1d092cd83117512f80251
Author: Matej Stuchlik <mstuchli at redhat.com>
Date: Fri Nov 8 12:11:59 2013 +0100
Change behavior of ssl.match_hostname() to follow RFC 6125 (rhbz#1023742)
...-change-match_hostname-to-follow-RFC-6125.patch | 188 ++++++++++++++++++++
python3.spec | 12 +-
2 files changed, 198 insertions(+), 2 deletions(-)
---
diff --git a/00187-change-match_hostname-to-follow-RFC-6125.patch b/00187-change-match_hostname-to-follow-RFC-6125.patch
new file mode 100644
index 0000000..0f02276
--- /dev/null
+++ b/00187-change-match_hostname-to-follow-RFC-6125.patch
@@ -0,0 +1,188 @@
+--- a/Doc/library/ssl.rst
++++ b/Doc/library/ssl.rst
+@@ -283,10 +283,10 @@ Certificate handling
+ Verify that *cert* (in decoded format as returned by
+ :meth:`SSLSocket.getpeercert`) matches the given *hostname*. The rules
+ applied are those for checking the identity of HTTPS servers as outlined
+- in :rfc:`2818`, except that IP addresses are not currently supported.
+- In addition to HTTPS, this function should be suitable for checking the
+- identity of servers in various SSL-based protocols such as FTPS, IMAPS,
+- POPS and others.
++ in :rfc:`2818` and :rfc:`6125`, except that IP addresses are not currently
++ supported. In addition to HTTPS, this function should be suitable for
++ checking the identity of servers in various SSL-based protocols such as
++ FTPS, IMAPS, POPS and others.
+
+ :exc:`CertificateError` is raised on failure. On success, the function
+ returns nothing::
+@@ -301,6 +301,13 @@ Certificate handling
+
+ .. versionadded:: 3.2
+
++ .. versionchanged:: 3.3.3
++ The function now follows :rfc:`6125`, section 6.4.3 and does neither
++ match multiple wildcards (e.g. ``*.*.com`` or ``*a*.example.org``) nor
++ a wildcard inside an internationalized domain names (IDN) fragment.
++ IDN A-labels such as ``www*.xn--pthon-kva.org`` are still supported,
++ but ``x*.python.org`` no longer matches ``xn--tda.python.org``.
++
+ .. function:: cert_time_to_seconds(timestring)
+
+ Returns a floating-point value containing a normal seconds-after-the-epoch
+unchanged:
+--- a/Lib/ssl.py
++++ b/Lib/ssl.py
+@@ -129,25 +129,53 @@ class CertificateError(ValueError):
+ pass
+
+
+-def _dnsname_to_pat(dn, max_wildcards=1):
++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 = []
+- for frag in dn.split(r'.'):
+- if frag.count('*') > max_wildcards:
+- # Issue #17980: avoid denials of service by refusing more
+- # than one wildcard per fragment. A survery of established
+- # policy among SSL implementations showed it to be a
+- # reasonable choice.
+- raise CertificateError(
+- "too many wildcards in certificate DNS name: " + repr(dn))
+- if frag == '*':
+- # When '*' is a fragment by itself, it matches a non-empty dotless
+- # fragment.
+- pats.append('[^.]+')
+- else:
+- # Otherwise, '*' matches any dotless fragment.
+- frag = re.escape(frag)
+- pats.append(frag.replace(r'\*', '[^.]*'))
+- return re.compile(r'\A' + r'\.'.join(pats) + r'\Z', re.IGNORECASE)
++ if not dn:
++ return False
++
++ leftmost, *remainder = dn.split(r'.')
++
++ wildcards = leftmost.count('*')
++ if wildcards > max_wildcards:
++ # Issue #17980: avoid denials of service by refusing more
++ # than one wildcard per fragment. A survery 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):
+unchanged:
+--- a/Lib/test/test_ssl.py
++++ b/Lib/test/test_ssl.py
+@@ -307,11 +307,7 @@ class BasicSocketTests(unittest.TestCase
+ fail(cert, 'Xa.com')
+ fail(cert, '.a.com')
+
+- cert = {'subject': ((('commonName', 'a.*.com'),),)}
+- ok(cert, 'a.foo.com')
+- fail(cert, 'a..com')
+- fail(cert, 'a.com')
+-
++ # only match one left-most wildcard
+ cert = {'subject': ((('commonName', 'f*.com'),),)}
+ ok(cert, 'foo.com')
+ ok(cert, 'f.com')
+@@ -326,6 +322,36 @@ class BasicSocketTests(unittest.TestCase
+ fail(cert, 'example.org')
+ fail(cert, 'null.python.org')
+
++ # error cases with wildcards
++ cert = {'subject': ((('commonName', '*.*.a.com'),),)}
++ fail(cert, 'bar.foo.a.com')
++ fail(cert, 'a.com')
++ fail(cert, 'Xa.com')
++ fail(cert, '.a.com')
++
++ cert = {'subject': ((('commonName', 'a.*.com'),),)}
++ fail(cert, 'a.foo.com')
++ fail(cert, 'a..com')
++ fail(cert, 'a.com')
++
++ # wildcard doesn't match IDNA prefix 'xn--'
++ idna = 'püthon.python.org'.encode("idna").decode("ascii")
++ cert = {'subject': ((('commonName', idna),),)}
++ ok(cert, idna)
++ cert = {'subject': ((('commonName', 'x*.python.org'),),)}
++ fail(cert, idna)
++ cert = {'subject': ((('commonName', 'xn--p*.python.org'),),)}
++ fail(cert, idna)
++
++ # wildcard in first fragment and IDNA A-labels in sequent fragments
++ # are supported.
++ idna = 'www*.pythön.org'.encode("idna").decode("ascii")
++ cert = {'subject': ((('commonName', idna),),)}
++ ok(cert, 'www.pythön.org'.encode("idna").decode("ascii"))
++ ok(cert, 'www1.pythön.org'.encode("idna").decode("ascii"))
++ fail(cert, 'ftp.pythön.org'.encode("idna").decode("ascii"))
++ fail(cert, 'pythön.org'.encode("idna").decode("ascii"))
++
+ # Slightly fake real-world example
+ cert = {'notAfter': 'Jun 26 21:41:46 2011 GMT',
+ 'subject': ((('commonName', 'linuxfrz.org'),),),
+@@ -386,7 +412,7 @@ class BasicSocketTests(unittest.TestCase
+ cert = {'subject': ((('commonName', 'a*b.com'),),)}
+ ok(cert, 'axxb.com')
+ cert = {'subject': ((('commonName', 'a*b.co*'),),)}
+- ok(cert, 'axxb.com')
++ fail(cert, 'axxb.com')
+ cert = {'subject': ((('commonName', 'a*b*.com'),),)}
+ with self.assertRaises(ssl.CertificateError) as cm:
+ ssl.match_hostname(cert, 'axxbxxc.com')
+--- a/Lib/ssl.py
++++ b/Lib/ssl.py
+@@ -192,7 +192,7 @@ def match_hostname(cert, hostname):
+ san = cert.get('subjectAltName', ())
+ for key, value in san:
+ if key == 'DNS':
+- if _dnsname_to_pat(value).match(hostname):
++ if _dnsname_match(value, hostname):
+ return
+ dnsnames.append(value)
+ if not dnsnames:
+@@ -203,7 +203,7 @@ def match_hostname(cert, hostname):
+ # XXX according to RFC 2818, the most specific Common Name
+ # must be used.
+ if key == 'commonName':
+- if _dnsname_to_pat(value).match(hostname):
++ if _dnsname_match(value, hostname):
+ return
+ dnsnames.append(value)
+ if len(dnsnames) > 1:
diff --git a/python3.spec b/python3.spec
index a824745..cd99a8a 100644
--- a/python3.spec
+++ b/python3.spec
@@ -126,7 +126,7 @@
Summary: Version 3 of the Python programming language aka Python 3000
Name: python3
Version: %{pybasever}.2
-Release: 7%{?dist}
+Release: 8%{?dist}
License: Python
Group: Development/Languages
@@ -623,6 +623,11 @@ Patch185: 00185-CVE-2013-4238-hostname-check-bypass-in-SSL-module.patch
# continuing bytecompilation for other files.
Patch186: 00186-dont-raise-from-py_compile.patch
+# 00187 #
+# Fix for rhbz#1023742
+# Change behaviour of ssl.match_hostname() to follow RFC 6125
+# See http://bugs.python.org/issue17997#msg194950 for more.
+Patch187: 00187-change-match_hostname-to-follow-RFC-6125.patch
# (New patches go here ^^^)
@@ -885,6 +890,7 @@ done
%patch184 -p1
%patch185 -p1
%patch186 -p1
+%patch187 -p1
# Currently (2010-01-15), http://docs.python.org/library is for 2.6, and there
# are many differences between 2.6 and the Python 3 library.
@@ -1301,7 +1307,6 @@ sed \
# ======================================================
%check
-
# first of all, check timestamps of bytecode files
find %{buildroot} -type f -a -name "*.py" -print0 | \
LD_LIBRARY_PATH="%{buildroot}%{dynload_dir}/:%{buildroot}%{_libdir}" \
@@ -1733,6 +1738,9 @@ rm -fr %{buildroot}
# ======================================================
%changelog
+* Fri Nov 08 2013 Matej Stuchlik <mstuchli at redhat.com> - 3.3.2-8
+- Changed behavior of ssl.match_hostname() to follow RFC 6125 (rhbz#1023742)
+
* Wed Oct 30 2013 Bohuslav Kabrda <bkabrda at redhat.com> - 3.3.2-7
- Bytecompile all *.py files properly during build (rhbz#1023607)
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