140 lines
4.7 KiB
PHP
140 lines
4.7 KiB
PHP
<?php
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/*
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+--------------------------------------------------------------------+
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| CiviCRM version 4.7 |
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+--------------------------------------------------------------------+
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| Copyright CiviCRM LLC (c) 2004-2017 |
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+--------------------------------------------------------------------+
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| This file is a part of CiviCRM. |
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| CiviCRM is free software; you can copy, modify, and distribute it |
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| under the terms of the GNU Affero General Public License |
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| Version 3, 19 November 2007 and the CiviCRM Licensing Exception. |
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| CiviCRM is distributed in the hope that it will be useful, but |
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| WITHOUT ANY WARRANTY; without even the implied warranty of |
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| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
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| See the GNU Affero General Public License for more details. |
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| You should have received a copy of the GNU Affero General Public |
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| License and the CiviCRM Licensing Exception along |
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| with this program; if not, contact CiviCRM LLC |
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| at info[AT]civicrm[DOT]org. If you have questions about the |
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| GNU Affero General Public License or the licensing of CiviCRM, |
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| see the CiviCRM license FAQ at http://civicrm.org/licensing |
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+--------------------------------------------------------------------+
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*/
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/**
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*
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* @package CRM
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* @copyright CiviCRM LLC (c) 2004-2017
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*/
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/**
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* A utility which signs and verifies a list of key-value pairs
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*
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* FIXME: Add TTL support?
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*
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* @code
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* $signer = new CRM_Utils_Signer('myprivatekey', array('param1','param2'));
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* $params = array(
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* 'param1' => 'hello',
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* 'param2' => 'world',
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* );
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* $token = $signer->sign($params);
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* ...
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* assertTrue($signer->validate($token, $params));
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* @endcode
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*/
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class CRM_Utils_Signer {
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/**
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* Expected length of the salt
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*
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* @var int
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*/
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const SALT_LEN = 4;
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/**
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* Instantiate a signature-processor
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*
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* @param string $secret
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* private.
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* @param array $paramNames
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* Array, fields which should be part of the signature.
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*/
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public function __construct($secret, $paramNames) {
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sort($paramNames); // ensure consistent serialization of payloads
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$this->secret = $secret;
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$this->paramNames = $paramNames;
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$this->signDelim = "_"; // chosen to be valid in URLs but not in salt or md5
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$this->defaultSalt = CRM_Utils_String::createRandom(self::SALT_LEN, CRM_Utils_String::ALPHANUMERIC);
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}
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/**
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* Generate a signature for a set of key-value pairs
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*
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* @param array $params
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* Array, key-value pairs.
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* @param string $salt
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* the salt (if known) or NULL (for auto-generated).
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* @return string, the full public token representing the signature
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*/
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public function sign($params, $salt = NULL) {
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$message = array();
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$message['secret'] = $this->secret;
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$message['payload'] = array();
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if (empty($salt)) {
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$message['salt'] = $this->createSalt();
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}
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else {
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$message['salt'] = $salt;
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}
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// recall: paramNames is pre-sorted for stability
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foreach ($this->paramNames as $paramName) {
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if (isset($params[$paramName])) {
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if (is_numeric($params[$paramName])) {
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$params[$paramName] = (string) $params[$paramName];
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}
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}
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else {
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// $paramName is not included or ===NULL
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$params[$paramName] = '';
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}
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$message['payload'][$paramName] = $params[$paramName];
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}
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$token = $message['salt'] . $this->signDelim . md5(serialize($message));
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return $token;
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}
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/**
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* Determine whether a token represents a proper signature for $params
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*
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* @param string $token
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* the full public token representing the signature.
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* @param array $params
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* Array, key-value pairs.
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*
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* @throws Exception
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* @return bool, TRUE iff all $paramNames for the submitted validate($params) and the original sign($params)
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*/
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public function validate($token, $params) {
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list ($salt, $signature) = explode($this->signDelim, $token);
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if (strlen($salt) != self::SALT_LEN) {
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throw new Exception("Token contains invalid salt [" . urlencode($token) . "]");
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}
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$newToken = $this->sign($params, $salt);
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return ($token == $newToken);
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}
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/**
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* @return string
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*/
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public function createSalt() {
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// It would be more secure to generate a new value but liable to run this
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// many times on certain admin pages; so instead we'll re-use the hash.
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return $this->defaultSalt;
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}
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}
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