python/patches/python-3.3.2-CVE-2013-2099.patch


# HG changeset patch
# User Antoine Pitrou <solipsis@pitrou.net>
# Date 1368892602 -7200
# Node ID c627638753e2d25a98950585b259104a025937a9
# Parent  9682241dc8fcb4b1aef083bd30860efa070c3d6d
Issue #17980: Fix possible abuse of ssl.match_hostname() for denial of service using certificates with many wildcards (CVE-2013-2099).

diff --git a/Lib/ssl.py b/Lib/ssl.py
--- a/Lib/ssl.py
+++ b/Lib/ssl.py
@@ -129,9 +129,16 @@ class CertificateError(ValueError):
     pass
 
 
-def _dnsname_to_pat(dn):
+def _dnsname_to_pat(dn, max_wildcards=1):
     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.
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -349,6 +349,17 @@ class BasicSocketTests(unittest.TestCase
         self.assertRaises(ValueError, ssl.match_hostname, None, 'example.com')
         self.assertRaises(ValueError, ssl.match_hostname, {}, 'example.com')
 
+        # Issue #17980: avoid denials of service by refusing more than one
+        # wildcard per fragment.
+        cert = {'subject': ((('commonName', 'a*b.com'),),)}
+        ok(cert, 'axxb.com')
+        cert = {'subject': ((('commonName', 'a*b.co*'),),)}
+        ok(cert, 'axxb.com')
+        cert = {'subject': ((('commonName', 'a*b*.com'),),)}
+        with self.assertRaises(ssl.CertificateError) as cm:
+            ssl.match_hostname(cert, 'axxbxxc.com')
+        self.assertIn("too many wildcards", str(cm.exception))
+
     def test_server_side(self):
         # server_hostname doesn't work for server sockets
         ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
1
2	# HG changeset patch
3	# User Antoine Pitrou <solipsis@pitrou.net>
4	# Date 1368892602 -7200
5	# Node ID c627638753e2d25a98950585b259104a025937a9
6	# Parent 9682241dc8fcb4b1aef083bd30860efa070c3d6d
7	Issue #17980: Fix possible abuse of ssl.match_hostname() for denial of service using certificates with many wildcards (CVE-2013-2099).
8
9	diff --git a/Lib/ssl.py b/Lib/ssl.py
10	--- a/Lib/ssl.py
11	+++ b/Lib/ssl.py
12	@@ -129,9 +129,16 @@ class CertificateError(ValueError):
13	pass
14
15
16	-def _dnsname_to_pat(dn):
17	+def _dnsname_to_pat(dn, max_wildcards=1):
18	pats = []
19	for frag in dn.split(r'.'):
20	+ if frag.count('*') > max_wildcards:
21	+ # Issue #17980: avoid denials of service by refusing more
22	+ # than one wildcard per fragment. A survery of established
23	+ # policy among SSL implementations showed it to be a
24	+ # reasonable choice.
25	+ raise CertificateError(
26	+ "too many wildcards in certificate DNS name: " + repr(dn))
27	if frag == '*':
28	# When '*' is a fragment by itself, it matches a non-empty dotless
29	# fragment.
30	diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
31	--- a/Lib/test/test_ssl.py
32	+++ b/Lib/test/test_ssl.py
33	@@ -349,6 +349,17 @@ class BasicSocketTests(unittest.TestCase
34	self.assertRaises(ValueError, ssl.match_hostname, None, 'example.com')
35	self.assertRaises(ValueError, ssl.match_hostname, {}, 'example.com')
36
37	+ # Issue #17980: avoid denials of service by refusing more than one
38	+ # wildcard per fragment.
39	+ cert = {'subject': ((('commonName', 'a*b.com'),),)}
40	+ ok(cert, 'axxb.com')
41	+ cert = {'subject': ((('commonName', 'ab.co'),),)}
42	+ ok(cert, 'axxb.com')
43	+ cert = {'subject': ((('commonName', 'ab.com'),),)}
44	+ with self.assertRaises(ssl.CertificateError) as cm:
45	+ ssl.match_hostname(cert, 'axxbxxc.com')
46	+ self.assertIn("too many wildcards", str(cm.exception))
47	+
48	def test_server_side(self):
49	# server_hostname doesn't work for server sockets
50	ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)