Fix CVE-2013-4073 - handling of certs with null bytes

Author: smalyshev

NEWS

@@ -101,6 +101,10 @@ PHP                                                                        NEWS
   . Fixed bug #61387 (NULL valued anonymous column causes segfault in 
     odbc_fetch_array). (Brandon Kirsch)
 
+- Openssl:
+  . Fixed handling null bytes in subjectAltName (CVE-2013-4073). 
+    (Christian Heimes)
+
 - PDO:
   . Allowed PDO_OCI to compile with Oracle Database 12c client libraries.
     (Chris Jones)

ext/openssl/openssl.c

@@ -1398,6 +1398,74 @@ PHP_FUNCTION(openssl_x509_check_private_key)
 }
 /* }}} */
 
+/* Special handling of subjectAltName, see CVE-2013-4073
+ * Christian Heimes
+ */
+
+static int openssl_x509v3_subjectAltName(BIO *bio, X509_EXTENSION *extension)
+{
+	GENERAL_NAMES *names;
+	const X509V3_EXT_METHOD *method = NULL;
+	long i, length, num;
+	const unsigned char *p;
+
+	method = X509V3_EXT_get(extension);
+	if (method == NULL) {
+		return -1;
+	}
+
+	p = extension->value->data;
+	length = extension->value->length;
+	if (method->it) {
+		names = (GENERAL_NAMES*)(ASN1_item_d2i(NULL, &p, length,
+						       ASN1_ITEM_ptr(method->it)));
+	} else {
+		names = (GENERAL_NAMES*)(method->d2i(NULL, &p, length));
+	}
+	if (names == NULL) {
+		return -1;
+	}
+
+	num = sk_GENERAL_NAME_num(names);
+	for (i = 0; i < num; i++) {
+			GENERAL_NAME *name;
+			ASN1_STRING *as;
+			name = sk_GENERAL_NAME_value(names, i);
+			switch (name->type) {
+				case GEN_EMAIL:
+					BIO_puts(bio, "email:");
+					as = name->d.rfc822Name;
+					BIO_write(bio, ASN1_STRING_data(as),
+						  ASN1_STRING_length(as));
+					break;
+				case GEN_DNS:
+					BIO_puts(bio, "DNS:");
+					as = name->d.dNSName;
+					BIO_write(bio, ASN1_STRING_data(as),
+						  ASN1_STRING_length(as));
+					break;
+				case GEN_URI:
+					BIO_puts(bio, "URI:");
+					as = name->d.uniformResourceIdentifier;
+					BIO_write(bio, ASN1_STRING_data(as),
+						  ASN1_STRING_length(as));
+					break;
+				default:
+					/* use builtin print for GEN_OTHERNAME, GEN_X400,
+					 * GEN_EDIPARTY, GEN_DIRNAME, GEN_IPADD and GEN_RID
+					 */
+					GENERAL_NAME_print(bio, name);
+			}
+			/* trailing ', ' except for last element */
+			if (i < (num - 1)) {
+				BIO_puts(bio, ", ");
+			}
+	}
+	sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
+
+	return 0;
+}
+
 /* {{{ proto array openssl_x509_parse(mixed x509 [, bool shortnames=true])
    Returns an array of the fields/values of the CERT */
 PHP_FUNCTION(openssl_x509_parse)
@@ -1494,15 +1562,29 @@ PHP_FUNCTION(openssl_x509_parse)
 
 
 	for (i = 0; i < X509_get_ext_count(cert); i++) {
+		int nid;
 		extension = X509_get_ext(cert, i);
-		if (OBJ_obj2nid(X509_EXTENSION_get_object(extension)) != NID_undef) {
+		nid = OBJ_obj2nid(X509_EXTENSION_get_object(extension));
+		if (nid != NID_undef) {
 			extname = (char *)OBJ_nid2sn(OBJ_obj2nid(X509_EXTENSION_get_object(extension)));
 		} else {
 			OBJ_obj2txt(buf, sizeof(buf)-1, X509_EXTENSION_get_object(extension), 1);
 			extname = buf;
 		}
 		bio_out = BIO_new(BIO_s_mem());
-		if (X509V3_EXT_print(bio_out, extension, 0, 0)) {
+		if (nid == NID_subject_alt_name) {
+			if (openssl_x509v3_subjectAltName(bio_out, extension) == 0) {
+				add_assoc_stringl(subitem, extname, bio_buf->data, bio_buf->length, 1);
+			} else {
+				zval_dtor(return_value);
+				if (certresource == -1 && cert) {
+					X509_free(cert);
+				}
+				BIO_free(bio_out);
+				RETURN_FALSE;
+			}
+		}
+		else if (X509V3_EXT_print(bio_out, extension, 0, 0)) {
 			BIO_get_mem_ptr(bio_out, &bio_buf);
 			add_assoc_stringl(subitem, extname, bio_buf->data, bio_buf->length, 1);
 		} else {

ext/openssl/tests/cve2013_4073.pem

@@ -0,0 +1,28 @@
+-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----

ext/openssl/tests/cve2013_4073.phpt

@@ -0,0 +1,19 @@
+--TEST--
+CVE 2013-4073: Null-byte certificate handling
+--SKIPIF--
+<?php 
+if (!extension_loaded("openssl")) die("skip");
+--FILE--
+<?php
+$cert = file_get_contents(__DIR__ . '/cve2013_4073.pem');
+$info = openssl_x509_parse($cert);
+var_export($info['extensions']);
+
+--EXPECTF--
+array (
+  'basicConstraints' => 'CA:FALSE',
+  'subjectKeyIdentifier' => '88:5A:55:C0:52:FF:61:CD:52:A3:35:0F:EA:5A:9C:24:38:22:F7:5C',
+  'keyUsage' => 'Digital Signature, Non Repudiation, Key Encipherment',
+  'subjectAltName' => 'DNS:altnull.python.org' . "\0" . 'example.com, email:null@python.org' . "\0" . 'user@example.org, URI:http://null.python.org' . "\0" . 'http://example.org, IP Address:192.0.2.1, IP Address:2001:DB8:0:0:0:0:0:1
+',
+)