# HG changeset patch # User Christian Heimes # Date 1376693687 -7200 # Node ID c9f073e593b037e8a29e386326859537691bcf62 # Parent 3105b78d34346ea36c52a3b7e635954f4b444120 Issue #18709: Fix CVE-2013-4238. The SSL module now handles NULL bytes inside subjectAltName correctly. Formerly the module has used OpenSSL's GENERAL_NAME_print() function to get the string represention of ASN.1 strings for rfc822Name (email), dNSName (DNS) and uniformResourceIdentifier (URI). diff --git a/Lib/test/nullbytecert.pem b/Lib/test/nullbytecert.pem new file mode 100644 --- /dev/null +++ b/Lib/test/nullbytecert.pem @@ -0,0 +1,90 @@ +Certificate: + Data: + Version: 3 (0x2) + Serial Number: 0 (0x0) + Signature Algorithm: sha1WithRSAEncryption + Issuer: C=US, ST=Oregon, L=Beaverton, O=Python Software Foundation, OU=Python Core Development, CN=null.python.org\x00example.org/emailAddress=python-dev@python.org + Validity + Not Before: Aug 7 13:11:52 2013 GMT + Not After : Aug 7 13:12:52 2013 GMT + Subject: C=US, ST=Oregon, L=Beaverton, O=Python Software Foundation, OU=Python Core Development, CN=null.python.org\x00example.org/emailAddress=python-dev@python.org + Subject Public Key Info: + Public Key Algorithm: rsaEncryption + Public-Key: (2048 bit) + Modulus: + 00:b5:ea:ed:c9:fb:46:7d:6f:3b:76:80:dd:3a:f3: + 03:94:0b:a7:a6:db:ec:1d:df:ff:23:74:08:9d:97: + 16:3f:a3:a4:7b:3e:1b:0e:96:59:25:03:a7:26:e2: + 88:a9:cf:79:cd:f7:04:56:b0:ab:79:32:6e:59:c1: + 32:30:54:eb:58:a8:cb:91:f0:42:a5:64:27:cb:d4: + 56:31:88:52:ad:cf:bd:7f:f0:06:64:1f:cc:27:b8: + a3:8b:8c:f3:d8:29:1f:25:0b:f5:46:06:1b:ca:02: + 45:ad:7b:76:0a:9c:bf:bb:b9:ae:0d:16:ab:60:75: + ae:06:3e:9c:7c:31:dc:92:2f:29:1a:e0:4b:0c:91: + 90:6c:e9:37:c5:90:d7:2a:d7:97:15:a3:80:8f:5d: + 7b:49:8f:54:30:d4:97:2c:1c:5b:37:b5:ab:69:30: + 68:43:d3:33:78:4b:02:60:f5:3c:44:80:a1:8f:e7: + f0:0f:d1:5e:87:9e:46:cf:62:fc:f9:bf:0c:65:12: + f1:93:c8:35:79:3f:c8:ec:ec:47:f5:ef:be:44:d5: + ae:82:1e:2d:9a:9f:98:5a:67:65:e1:74:70:7c:cb: + d3:c2:ce:0e:45:49:27:dc:e3:2d:d4:fb:48:0e:2f: + 9e:77:b8:14:46:c0:c4:36:ca:02:ae:6a:91:8c:da: + 2f:85 + Exponent: 65537 (0x10001) + X509v3 extensions: + X509v3 Basic Constraints: critical + CA:FALSE + X509v3 Subject Key Identifier: + 88:5A:55:C0:52:FF:61:CD:52:A3:35:0F:EA:5A:9C:24:38:22:F7:5C + X509v3 Key Usage: + Digital Signature, Non Repudiation, Key Encipherment + X509v3 Subject Alternative Name: + ************************************************************* + WARNING: The values for DNS, email and URI are WRONG. OpenSSL + doesn't print the text after a NULL byte. + ************************************************************* + DNS:altnull.python.org, email:null@python.org, URI:http://null.python.org, IP Address:192.0.2.1, IP Address:2001:DB8:0:0:0:0:0:1 + Signature Algorithm: sha1WithRSAEncryption + ac:4f:45:ef:7d:49:a8:21:70:8e:88:59:3e:d4:36:42:70:f5: + a3:bd:8b:d7:a8:d0:58:f6:31:4a:b1:a4:a6:dd:6f:d9:e8:44: + 3c:b6:0a:71:d6:7f:b1:08:61:9d:60:ce:75:cf:77:0c:d2:37: + 86:02:8d:5e:5d:f9:0f:71:b4:16:a8:c1:3d:23:1c:f1:11:b3: + 56:6e:ca:d0:8d:34:94:e6:87:2a:99:f2:ae:ae:cc:c2:e8:86: + de:08:a8:7f:c5:05:fa:6f:81:a7:82:e6:d0:53:9d:34:f4:ac: + 3e:40:fe:89:57:7a:29:a4:91:7e:0b:c6:51:31:e5:10:2f:a4: + 60:76:cd:95:51:1a:be:8b:a1:b0:fd:ad:52:bd:d7:1b:87:60: + d2:31:c7:17:c4:18:4f:2d:08:25:a3:a7:4f:b7:92:ca:e2:f5: + 25:f1:54:75:81:9d:b3:3d:61:a2:f7:da:ed:e1:c6:6f:2c:60: + 1f:d8:6f:c5:92:05:ab:c9:09:62:49:a9:14:ad:55:11:cc:d6: + 4a:19:94:99:97:37:1d:81:5f:8b:cf:a3:a8:96:44:51:08:3d: + 0b:05:65:12:eb:b6:70:80:88:48:72:4f:c6:c2:da:cf:cd:8e: + 5b:ba:97:2f:60:b4:96:56:49:5e:3a:43:76:63:04:be:2a:f6: + c1:ca:a9:94 +-----BEGIN CERTIFICATE----- +MIIE2DCCA8CgAwIBAgIBADANBgkqhkiG9w0BAQUFADCBxTELMAkGA1UEBhMCVVMx +DzANBgNVBAgMBk9yZWdvbjESMBAGA1UEBwwJQmVhdmVydG9uMSMwIQYDVQQKDBpQ +eXRob24gU29mdHdhcmUgRm91bmRhdGlvbjEgMB4GA1UECwwXUHl0aG9uIENvcmUg +RGV2ZWxvcG1lbnQxJDAiBgNVBAMMG251bGwucHl0aG9uLm9yZwBleGFtcGxlLm9y +ZzEkMCIGCSqGSIb3DQEJARYVcHl0aG9uLWRldkBweXRob24ub3JnMB4XDTEzMDgw +NzEzMTE1MloXDTEzMDgwNzEzMTI1MlowgcUxCzAJBgNVBAYTAlVTMQ8wDQYDVQQI +DAZPcmVnb24xEjAQBgNVBAcMCUJlYXZlcnRvbjEjMCEGA1UECgwaUHl0aG9uIFNv +ZnR3YXJlIEZvdW5kYXRpb24xIDAeBgNVBAsMF1B5dGhvbiBDb3JlIERldmVsb3Bt +ZW50MSQwIgYDVQQDDBtudWxsLnB5dGhvbi5vcmcAZXhhbXBsZS5vcmcxJDAiBgkq +hkiG9w0BCQEWFXB5dGhvbi1kZXZAcHl0aG9uLm9yZzCCASIwDQYJKoZIhvcNAQEB +BQADggEPADCCAQoCggEBALXq7cn7Rn1vO3aA3TrzA5QLp6bb7B3f/yN0CJ2XFj+j +pHs+Gw6WWSUDpybiiKnPec33BFawq3kyblnBMjBU61ioy5HwQqVkJ8vUVjGIUq3P +vX/wBmQfzCe4o4uM89gpHyUL9UYGG8oCRa17dgqcv7u5rg0Wq2B1rgY+nHwx3JIv +KRrgSwyRkGzpN8WQ1yrXlxWjgI9de0mPVDDUlywcWze1q2kwaEPTM3hLAmD1PESA +oY/n8A/RXoeeRs9i/Pm/DGUS8ZPINXk/yOzsR/XvvkTVroIeLZqfmFpnZeF0cHzL +08LODkVJJ9zjLdT7SA4vnne4FEbAxDbKAq5qkYzaL4UCAwEAAaOB0DCBzTAMBgNV +HRMBAf8EAjAAMB0GA1UdDgQWBBSIWlXAUv9hzVKjNQ/qWpwkOCL3XDALBgNVHQ8E +BAMCBeAwgZAGA1UdEQSBiDCBhYIeYWx0bnVsbC5weXRob24ub3JnAGV4YW1wbGUu +Y29tgSBudWxsQHB5dGhvbi5vcmcAdXNlckBleGFtcGxlLm9yZ4YpaHR0cDovL251 +bGwucHl0aG9uLm9yZwBodHRwOi8vZXhhbXBsZS5vcmeHBMAAAgGHECABDbgAAAAA +AAAAAAAAAAEwDQYJKoZIhvcNAQEFBQADggEBAKxPRe99SaghcI6IWT7UNkJw9aO9 +i9eo0Fj2MUqxpKbdb9noRDy2CnHWf7EIYZ1gznXPdwzSN4YCjV5d+Q9xtBaowT0j +HPERs1ZuytCNNJTmhyqZ8q6uzMLoht4IqH/FBfpvgaeC5tBTnTT0rD5A/olXeimk +kX4LxlEx5RAvpGB2zZVRGr6LobD9rVK91xuHYNIxxxfEGE8tCCWjp0+3ksri9SXx +VHWBnbM9YaL32u3hxm8sYB/Yb8WSBavJCWJJqRStVRHM1koZlJmXNx2BX4vPo6iW +RFEIPQsFZRLrtnCAiEhyT8bC2s/Njlu6ly9gtJZWSV46Q3ZjBL4q9sHKqZQ= +-----END CERTIFICATE----- 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 @@ -55,6 +55,7 @@ BADCERT = data_file("badcert.pem") WRONGCERT = data_file("XXXnonexisting.pem") BADKEY = data_file("badkey.pem") NOKIACERT = data_file("nokia.pem") +NULLBYTECERT = data_file("nullbytecert.pem") DHFILE = data_file("dh512.pem") BYTES_DHFILE = os.fsencode(DHFILE) @@ -162,6 +163,27 @@ class BasicSocketTests(unittest.TestCase ('DNS', 'projects.forum.nokia.com')) ) + def test_parse_cert_CVE_2013_4238(self): + p = ssl._ssl._test_decode_cert(NULLBYTECERT) + if support.verbose: + sys.stdout.write("\n" + pprint.pformat(p) + "\n") + subject = ((('countryName', 'US'),), + (('stateOrProvinceName', 'Oregon'),), + (('localityName', 'Beaverton'),), + (('organizationName', 'Python Software Foundation'),), + (('organizationalUnitName', 'Python Core Development'),), + (('commonName', 'null.python.org\x00example.org'),), + (('emailAddress', 'python-dev@python.org'),)) + self.assertEqual(p['subject'], subject) + self.assertEqual(p['issuer'], subject) + self.assertEqual(p['subjectAltName'], + (('DNS', 'altnull.python.org\x00example.com'), + ('email', 'null@python.org\x00user@example.org'), + ('URI', 'http://null.python.org\x00http://example.org'), + ('IP Address', '192.0.2.1'), + ('IP Address', '2001:DB8:0:0:0:0:0:1\n')) + ) + def test_DER_to_PEM(self): with open(SVN_PYTHON_ORG_ROOT_CERT, 'r') as f: pem = f.read() @@ -294,6 +316,13 @@ class BasicSocketTests(unittest.TestCase fail(cert, 'foo.a.com') fail(cert, 'bar.foo.com') + # NULL bytes are bad, CVE-2013-4073 + cert = {'subject': ((('commonName', + 'null.python.org\x00example.org'),),)} + ok(cert, 'null.python.org\x00example.org') # or raise an error? + fail(cert, 'example.org') + fail(cert, 'null.python.org') + # Slightly fake real-world example cert = {'notAfter': 'Jun 26 21:41:46 2011 GMT', 'subject': ((('commonName', 'linuxfrz.org'),),), diff --git a/Modules/_ssl.c b/Modules/_ssl.c --- a/Modules/_ssl.c +++ b/Modules/_ssl.c @@ -771,12 +771,14 @@ static PyObject * ext->value->length)); for(j = 0; j < sk_GENERAL_NAME_num(names); j++) { - /* get a rendering of each name in the set of names */ + int gntype; + ASN1_STRING *as = NULL; name = sk_GENERAL_NAME_value(names, j); - if (name->type == GEN_DIRNAME) { - + gntype = name-> type; + switch (gntype) { + case GEN_DIRNAME: /* we special-case DirName as a tuple of tuples of attributes */ @@ -798,11 +800,62 @@ static PyObject * goto fail; } PyTuple_SET_ITEM(t, 1, v); + break; - } else { + case GEN_EMAIL: + case GEN_DNS: + case GEN_URI: + /* GENERAL_NAME_print() doesn't handle NULL bytes in ASN1_string + correctly, CVE-2013-4238 */ + t = PyTuple_New(2); + if (t == NULL) + goto fail; + switch (gntype) { + case GEN_EMAIL: + v = PyUnicode_FromString("email"); + as = name->d.rfc822Name; + break; + case GEN_DNS: + v = PyUnicode_FromString("DNS"); + as = name->d.dNSName; + break; + case GEN_URI: + v = PyUnicode_FromString("URI"); + as = name->d.uniformResourceIdentifier; + break; + } + if (v == NULL) { + Py_DECREF(t); + goto fail; + } + PyTuple_SET_ITEM(t, 0, v); + v = PyUnicode_FromStringAndSize((char *)ASN1_STRING_data(as), + ASN1_STRING_length(as)); + if (v == NULL) { + Py_DECREF(t); + goto fail; + } + PyTuple_SET_ITEM(t, 1, v); + break; + default: /* for everything else, we use the OpenSSL print form */ - + switch (gntype) { + /* check for new general name type */ + case GEN_OTHERNAME: + case GEN_X400: + case GEN_EDIPARTY: + case GEN_IPADD: + case GEN_RID: + break; + default: + if (PyErr_WarnFormat(PyExc_RuntimeWarning, 1, + "Unknown general name type %d", + gntype) == -1) { + goto fail; + } + break; + } (void) BIO_reset(biobuf); GENERAL_NAME_print(biobuf, name); len = BIO_gets(biobuf, buf, sizeof(buf)-1); @@ -829,6 +882,7 @@ static PyObject * goto fail; } PyTuple_SET_ITEM(t, 1, v); + break; } /* and add that rendering to the list */