Improve normalization and sanitization of memcached keys

[lhc/web/wiklou.git] / includes / objectcache / MemcachedBagOStuff.php

diff --git a/includes/objectcache/MemcachedBagOStuff.php b/includes/objectcache/MemcachedBagOStuff.php
index e545aa5..12ba83e 100644 (file)
--- a/includes/objectcache/MemcachedBagOStuff.php
+++ b/includes/objectcache/MemcachedBagOStuff.php
@@ -27,6 +27,7 @@
  * @ingroup Cache
  */
 class MemcachedBagOStuff extends BagOStuff {
+       /** @var MWMemcached|Memcached */
        protected $client;
 
        /**
@@ -57,53 +58,36 @@ class MemcachedBagOStuff extends BagOStuff {
                return $params;
        }
 
-       public function get( $key, &$casToken = null, $flags = 0 ) {
+       protected function doGet( $key, $flags = 0 ) {
+               $casToken = null;
+
+               return $this->getWithToken( $key, $casToken, $flags );
+       }
+
+       protected function getWithToken( $key, &$casToken, $flags = 0 ) {
                return $this->client->get( $this->encodeKey( $key ), $casToken );
        }
 
-       /**
-        * @param string $key
-        * @param mixed $value
-        * @param int $exptime
-        * @return bool
-        */
-       public function set( $key, $value, $exptime = 0 ) {
+       public function set( $key, $value, $exptime = 0, $flags = 0 ) {
                return $this->client->set( $this->encodeKey( $key ), $value,
                        $this->fixExpiry( $exptime ) );
        }
 
-       /**
-        * @param mixed $casToken
-        * @param string $key
-        * @param mixed $value
-        * @param int $exptime
-        * @return bool
-        */
        protected function cas( $casToken, $key, $value, $exptime = 0 ) {
                return $this->client->cas( $casToken, $this->encodeKey( $key ),
                        $value, $this->fixExpiry( $exptime ) );
        }
 
-       /**
-        * @param string $key
-        * @return bool
-        */
        public function delete( $key ) {
                return $this->client->delete( $this->encodeKey( $key ) );
        }
 
-       /**
-        * @param string $key
-        * @param int $value
-        * @param int $exptime (default 0)
-        * @return mixed
-        */
        public function add( $key, $value, $exptime = 0 ) {
                return $this->client->add( $this->encodeKey( $key ), $value,
                        $this->fixExpiry( $exptime ) );
        }
 
-       public function merge( $key, $callback, $exptime = 0, $attempts = 10 ) {
+       public function merge( $key, $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
                if ( !is_callable( $callback ) ) {
                        throw new Exception( "Got invalid callback." );
                }
@@ -120,6 +104,46 @@ class MemcachedBagOStuff extends BagOStuff {
                return $this->client;
        }
 
+       /**
+        * Construct a cache key.
+        *
+        * @since 1.27
+        * @param string $keyspace
+        * @param array $args
+        * @return string
+        */
+       public function makeKeyInternal( $keyspace, $args ) {
+               // Memcached keys have a maximum length of 255 characters. From that,
+               // subtract the number of characters we need for the keyspace and for
+               // the separator character needed for each argument.
+               $charsLeft = 255 - strlen( $keyspace ) - count( $args );
+
+               $that = $this;
+               $args = array_map(
+                       function ( $arg ) use ( $that, &$charsLeft ) {
+                               // Because MemcachedBagOStuff::encodeKey() will be called again
+                               // with this input once the key is actually used, we have to
+                               // encode pound signs here rather than in encodeKey().
+                               $arg = $that->encodeKey( str_replace( '#', '%23', $arg ) );
+
+                               // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
+                               if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
+                                       $arg = '#' . md5( $arg );
+                               }
+
+                               $charsLeft -= strlen( $arg );
+                               return $arg;
+                       },
+                       $args
+               );
+
+               if ( $charsLeft < 0 ) {
+                       $args = array( '##' . md5( implode( ':', $args ) ) );
+               }
+
+               return parent::makeKeyInternal( $keyspace, $args );
+       }
+
        /**
         * Encode a key for use on the wire inside the memcached protocol.
         *
@@ -131,7 +155,7 @@ class MemcachedBagOStuff extends BagOStuff {
         * @return string
         */
        public function encodeKey( $key ) {
-               return preg_replace_callback( '/[\x00-\x20\x25\x7f]+/',
+               return preg_replace_callback( '/[^\x21-\x7e]+/',
                        array( $this, 'encodeKeyCallback' ), $key );
        }
 
@@ -168,7 +192,10 @@ class MemcachedBagOStuff extends BagOStuff {
         * @return string
         */
        public function decodeKey( $key ) {
-               return urldecode( $key );
+               // matches %00-%20, %25, %7F (=decoded alternatives for those encoded in encodeKey)
+               return preg_replace_callback( '/%([0-1][0-9]|20|25|7F)/i', function ( $match ) {
+                       return urldecode( $match[0] );
+               }, $key );
        }
 
        /**