bpo-35746: Fix segfault in ssl's cert parser (GH-11569)

Fix a NULL pointer deref in ssl module. The cert parser did not handle CRL
distribution points with empty DP or URI correctly. A malicious or buggy
certificate can result into segfault.

Signed-off-by: Christian Heimes <christian@python.org>



https://bugs.python.org/issue35746
This commit is contained in:
Christian Heimes 2019-01-15 23:47:42 +01:00 committed by Miss Islington (bot)
parent c9f872b0bd
commit a37f52436f
4 changed files with 51 additions and 0 deletions

View file

@ -115,6 +115,7 @@ NONEXISTINGCERT = data_file("XXXnonexisting.pem")
BADKEY = data_file("badkey.pem")
NOKIACERT = data_file("nokia.pem")
NULLBYTECERT = data_file("nullbytecert.pem")
TALOS_INVALID_CRLDP = data_file("talos-2019-0758.pem")
DHFILE = data_file("ffdh3072.pem")
BYTES_DHFILE = os.fsencode(DHFILE)
@ -348,6 +349,27 @@ class BasicSocketTests(unittest.TestCase):
self.assertEqual(p['crlDistributionPoints'],
('http://SVRIntl-G3-crl.verisign.com/SVRIntlG3.crl',))
def test_parse_cert_CVE_2019_5010(self):
p = ssl._ssl._test_decode_cert(TALOS_INVALID_CRLDP)
if support.verbose:
sys.stdout.write("\n" + pprint.pformat(p) + "\n")
self.assertEqual(
p,
{
'issuer': (
(('countryName', 'UK'),), (('commonName', 'cody-ca'),)),
'notAfter': 'Jun 14 18:00:58 2028 GMT',
'notBefore': 'Jun 18 18:00:58 2018 GMT',
'serialNumber': '02',
'subject': ((('countryName', 'UK'),),
(('commonName',
'codenomicon-vm-2.test.lal.cisco.com'),)),
'subjectAltName': (
('DNS', 'codenomicon-vm-2.test.lal.cisco.com'),),
'version': 3
}
)
def test_parse_cert_CVE_2013_4238(self):
p = ssl._ssl._test_decode_cert(NULLBYTECERT)
if support.verbose: