<?php
/*
* Copyright 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Verifies signatures using PEM encoded certificates.
*
* @author Brian Eaton <beaton@google.com>
*/
class Google_PemVerifier extends Google_Verifier {
private $publicKey;
/**
* Constructs a verifier from the supplied PEM-encoded certificate.
*
* $pem: a PEM encoded certificate (not a file).
* @param $pem
* @throws Google_AuthException
* @throws Google_Exception
*/
function __construct($pem) {
if (!function_exists('openssl_x509_read')) {
throw new Google_Exception('Google API PHP client needs the openssl PHP extension');
}
$this->publicKey = openssl_x509_read($pem);
if (!$this->publicKey) {
throw new Google_AuthException("Unable to parse PEM: ".esc_html($pem));
}
}
function __destruct() {
if ($this->publicKey) {
openssl_x509_free($this->publicKey);
}
}
/**
* Verifies the signature on data.
*
* Returns true if the signature is valid, false otherwise.
* @param $data
* @param $signature
* @throws Google_AuthException
* @return bool
*/
function verify($data, $signature) {
$status = openssl_verify($data, $signature, $this->publicKey, "sha256");
if ($status === -1) {
throw new Google_AuthException('Signature verification error: ' . esc_html(openssl_error_string()));
}
return $status === 1;
}
}