MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / includes / session / Token.php

diff --git a/includes/session/Token.php b/includes/session/Token.php
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+<?php
+/**
+ * MediaWiki session token
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Session
+ */
+
+namespace MediaWiki\Session;
+
+/**
+ * Value object representing a CSRF token
+ *
+ * @ingroup Session
+ * @since 1.27
+ */
+class Token {
+       /** CSRF token suffix. Plus and terminal backslash are included to stop
+        * editing from certain broken proxies. */
+       const SUFFIX = '+\\';
+
+       private $secret = '';
+       private $salt = '';
+       private $new = false;
+
+       /**
+        * @param string $secret Token secret
+        * @param string $salt Token salt
+        * @param bool $new Whether the secret was newly-created
+        */
+       public function __construct( $secret, $salt, $new = false ) {
+               $this->secret = $secret;
+               $this->salt = $salt;
+               $this->new = $new;
+       }
+
+       /**
+        * Decode the timestamp from a token string
+        *
+        * Does not validate the token beyond the syntactic checks necessary to
+        * be able to extract the timestamp.
+        *
+        * @param string $token
+        * @return int|null
+        */
+       public static function getTimestamp( $token ) {
+               $suffixLen = strlen( self::SUFFIX );
+               $len = strlen( $token );
+               if ( $len <= 32 + $suffixLen ||
+                       substr( $token, -$suffixLen ) !== self::SUFFIX ||
+                       strspn( $token, '0123456789abcdef' ) + $suffixLen !== $len
+               ) {
+                       return null;
+               }
+
+               return hexdec( substr( $token, 32, -$suffixLen ) );
+       }
+
+       /**
+        * Get the string representation of the token at a timestamp
+        * @param int $timestamp
+        * @return string
+        */
+       protected function toStringAtTimestamp( $timestamp ) {
+               return hash_hmac( 'md5', $timestamp . $this->salt, $this->secret, false ) .
+                       dechex( $timestamp ) .
+                       self::SUFFIX;
+       }
+
+       /**
+        * Get the string representation of the token
+        * @return string
+        */
+       public function toString() {
+               return $this->toStringAtTimestamp( wfTimestamp() );
+       }
+
+       public function __toString() {
+               return $this->toString();
+       }
+
+       /**
+        * Test if the token-string matches this token
+        * @param string $userToken
+        * @param int|null $maxAge Return false if $userToken is older than this many seconds
+        * @return bool
+        */
+       public function match( $userToken, $maxAge = null ) {
+               $timestamp = self::getTimestamp( $userToken );
+               if ( $timestamp === null ) {
+                       return false;
+               }
+               if ( $maxAge !== null && $timestamp < wfTimestamp() - $maxAge ) {
+                       // Expired token
+                       return false;
+               }
+
+               $sessionToken = $this->toStringAtTimestamp( $timestamp );
+               return hash_equals( $sessionToken, $userToken );
+       }
+
+       /**
+        * Indicate whether this token was just created
+        * @return bool
+        */
+       public function wasNew() {
+               return $this->new;
+       }
+
+}