Fix crash in openssl_x509_parse() when X509_NAME_oneline() fails

The X509_NAME_oneline() function can return NULL, which will cause a
crash when the string length is computed via add_assoc_string().

Closes phpGH-21010.

Author: ndossche

NEWS

@@ -34,6 +34,8 @@ PHP                                                                        NEWS
   . Fix memory leaks when sk_X509_new_null() fails. (ndossche)
   . Fix crash when in openssl_x509_parse() when i2s_ASN1_INTEGER() fails.
     (ndossche)
+  . Fix crash in openssl_x509_parse() when X509_NAME_oneline() fails.
+    (ndossche)
 
 - Phar:
   . Fixed bug GH-20882 (buildFromIterator breaks with missing base directory).

ext/openssl/openssl.c

@@ -2134,6 +2134,11 @@ PHP_FUNCTION(openssl_x509_parse)
 
 	subject_name = X509_get_subject_name(cert);
 	cert_name = X509_NAME_oneline(subject_name, NULL, 0);
+	if (cert_name == NULL) {
+		php_openssl_store_errors();
+		goto err;
+	}
+
 	add_assoc_string(return_value, "name", cert_name);
 	OPENSSL_free(cert_name);