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- From be5de958e9052e322b0087c6dba81cdad0c3e031 Mon Sep 17 00:00:00 2001
- From: "Miss Islington (bot)"
- <31488909+miss-islington@users.noreply.github.com>
- Date: Tue, 15 Jan 2019 15:03:36 -0800
- Subject: [PATCH] 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
- (cherry picked from commit a37f52436f9aa4b9292878b72f3ff1480e2606c3)
-
- Co-authored-by: Christian Heimes <christian@python.org>
- ---
- Lib/test/talos-2019-0758.pem | 22 +++++++++++++++++++
- Lib/test/test_ssl.py | 22 +++++++++++++++++++
- .../2019-01-15-18-16-05.bpo-35746.nMSd0j.rst | 3 +++
- Modules/_ssl.c | 4 ++++
- 4 files changed, 51 insertions(+)
- create mode 100644 Lib/test/talos-2019-0758.pem
- create mode 100644 Misc/NEWS.d/next/Security/2019-01-15-18-16-05.bpo-35746.nMSd0j.rst
-
- diff --git a/Lib/test/talos-2019-0758.pem b/Lib/test/talos-2019-0758.pem
- new file mode 100644
- index 0000000000..13b95a77fd
- --- /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 f1b9565c8d..b6794ce3a8 100644
- --- a/Lib/test/test_ssl.py
- +++ b/Lib/test/test_ssl.py
- @@ -116,6 +116,7 @@ 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)
- @@ -365,6 +366,27 @@ 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 0000000000..dffe347eec
- --- /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 9894ad821d..9baec8a9bc 100644
- --- a/Modules/_ssl.c
- +++ b/Modules/_ssl.c
- @@ -1516,6 +1516,10 @@ _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++) {
- --
- 2.17.1
-
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