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| author | Christian Heimes <christian@python.org> | 2019-01-15 22:47:42 (GMT) |
|---|---|---|
| committer | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2019-01-15 22:47:42 (GMT) |
| commit | a37f52436f9aa4b9292878b72f3ff1480e2606c3 (patch) | |
| tree | 241263055db201418a7288a883eefd783ff59364 | |
| parent | c9f872b0bdce5888f1879fa74e098bf4a05430c5 (diff) | |
| download | cpython-a37f52436f9aa4b9292878b72f3ff1480e2606c3.zip cpython-a37f52436f9aa4b9292878b72f3ff1480e2606c3.tar.gz cpython-a37f52436f9aa4b9292878b72f3ff1480e2606c3.tar.bz2 | |
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
| -rw-r--r-- | Lib/test/talos-2019-0758.pem | 22 | ||||
| -rw-r--r-- | Lib/test/test_ssl.py | 22 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Security/2019-01-15-18-16-05.bpo-35746.nMSd0j.rst | 3 | ||||
| -rw-r--r-- | Modules/_ssl.c | 4 |
4 files changed, 51 insertions, 0 deletions
diff --git a/Lib/test/talos-2019-0758.pem b/Lib/test/talos-2019-0758.pem new file mode 100644 index 0000000..13b95a7 --- /dev/null +++ b/Lib/test/talos-2019-0758.pem @@ -0,0 +1,22 @@ +-----BEGIN CERTIFICATE----- +MIIDqDCCApKgAwIBAgIBAjALBgkqhkiG9w0BAQswHzELMAkGA1UEBhMCVUsxEDAO +BgNVBAMTB2NvZHktY2EwHhcNMTgwNjE4MTgwMDU4WhcNMjgwNjE0MTgwMDU4WjA7 +MQswCQYDVQQGEwJVSzEsMCoGA1UEAxMjY29kZW5vbWljb24tdm0tMi50ZXN0Lmxh +bC5jaXNjby5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC63fGB +J80A9Av1GB0bptslKRIUtJm8EeEu34HkDWbL6AJY0P8WfDtlXjlPaLqFa6sqH6ES +V48prSm1ZUbDSVL8R6BYVYpOlK8/48xk4pGTgRzv69gf5SGtQLwHy8UPBKgjSZoD +5a5k5wJXGswhKFFNqyyxqCvWmMnJWxXTt2XDCiWc4g4YAWi4O4+6SeeHVAV9rV7C +1wxqjzKovVe2uZOHjKEzJbbIU6JBPb6TRfMdRdYOw98n1VXDcKVgdX2DuuqjCzHP +WhU4Tw050M9NaK3eXp4Mh69VuiKoBGOLSOcS8reqHIU46Reg0hqeL8LIL6OhFHIF +j7HR6V1X6F+BfRS/AgMBAAGjgdYwgdMwCQYDVR0TBAIwADAdBgNVHQ4EFgQUOktp +HQjxDXXUg8prleY9jeLKeQ4wTwYDVR0jBEgwRoAUx6zgPygZ0ZErF9sPC4+5e2Io +UU+hI6QhMB8xCzAJBgNVBAYTAlVLMRAwDgYDVQQDEwdjb2R5LWNhggkA1QEAuwb7 +2s0wCQYDVR0SBAIwADAuBgNVHREEJzAlgiNjb2Rlbm9taWNvbi12bS0yLnRlc3Qu +bGFsLmNpc2NvLmNvbTAOBgNVHQ8BAf8EBAMCBaAwCwYDVR0fBAQwAjAAMAsGCSqG +SIb3DQEBCwOCAQEAvqantx2yBlM11RoFiCfi+AfSblXPdrIrHvccepV4pYc/yO6p +t1f2dxHQb8rWH3i6cWag/EgIZx+HJQvo0rgPY1BFJsX1WnYf1/znZpkUBGbVmlJr +t/dW1gSkNS6sPsM0Q+7HPgEv8CPDNK5eo7vU2seE0iWOkxSyVUuiCEY9ZVGaLVit +p0C78nZ35Pdv4I+1cosmHl28+es1WI22rrnmdBpH8J1eY6WvUw2xuZHLeNVN0TzV +Q3qq53AaCWuLOD1AjESWuUCxMZTK9DPS4JKXTK8RLyDeqOvJGjsSWp3kL0y3GaQ+ +10T1rfkKJub2+m9A9duin1fn6tHc2wSvB7m3DA== +-----END CERTIFICATE----- diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py index 7f6b931..1fc657f 100644 --- a/Lib/test/test_ssl.py +++ b/Lib/test/test_ssl.py @@ -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: diff --git a/Misc/NEWS.d/next/Security/2019-01-15-18-16-05.bpo-35746.nMSd0j.rst b/Misc/NEWS.d/next/Security/2019-01-15-18-16-05.bpo-35746.nMSd0j.rst new file mode 100644 index 0000000..dffe347 --- /dev/null +++ b/Misc/NEWS.d/next/Security/2019-01-15-18-16-05.bpo-35746.nMSd0j.rst @@ -0,0 +1,3 @@ +[CVE-2019-5010] 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. diff --git a/Modules/_ssl.c b/Modules/_ssl.c index 4e3352d..0e720e2 100644 --- a/Modules/_ssl.c +++ b/Modules/_ssl.c @@ -1515,6 +1515,10 @@ _get_crl_dp(X509 *certificate) { STACK_OF(GENERAL_NAME) *gns; dp = sk_DIST_POINT_value(dps, i); + if (dp->distpoint == NULL) { + /* Ignore empty DP value, CVE-2019-5010 */ + continue; + } gns = dp->distpoint->name.fullname; for (j=0; j < sk_GENERAL_NAME_num(gns); j++) { |