openssl: Use proper error propagation when X509_dup() fails in openssl_x509_read()

Otherwise x509 field is NULL and can cause a NULL deref which is UB (and
causes a SEGV).

Author: ndossche

ext/openssl/openssl.c

@@ -2517,9 +2517,20 @@ PHP_FUNCTION(openssl_x509_read)
 		RETURN_FALSE;
 	}
 
+	X509 *obj_x509;
+	if (cert_obj) {
+		obj_x509 = X509_dup(cert);
+		if (!obj_x509) {
+			php_error_docref(NULL, E_WARNING, "X.509 Certificate could not be duplicated");
+			RETURN_FALSE;
+		}
+	} else {
+		obj_x509 = cert;
+	}
+
 	object_init_ex(return_value, php_openssl_certificate_ce);
 	x509_cert_obj = Z_OPENSSL_CERTIFICATE_P(return_value);
-	x509_cert_obj->x509 = cert_obj ? X509_dup(cert) : cert;
+	x509_cert_obj->x509 = obj_x509;
 }
 /* }}} */