Changed template inclusion code to detect loops and to limit the text length.

Based on an algorithm proposed by Emmanuel Engelhardt in
http://mail.wikipedia.org/pipermail/wikitech-l/2004-July/011254.html
slightly modified.

diff --git a/includes/Parser.php b/includes/Parser.php
index bcaf49f..aa3c239 100644 (file)
--- a/includes/Parser.php
+++ b/includes/Parser.php
@@ -31,6 +31,7 @@
 #
 
 define( "MAX_INCLUDE_REPEAT", 5 );
+define( "MAX_INCLUDE_SIZE", 1000000 ); // 1 Million
 
 # Allowed values for $mOutputType
 define( "OT_HTML", 1 );
@@ -56,9 +57,15 @@ class Parser
        var $mVariables, $mIncludeCount, $mArgStack, $mLastSection, $mInPre;
 
        # Temporary:
-       var $mOptions, $mTitle, $mOutputType;
+       var $mOptions, $mTitle, $mOutputType,
+           $mTemplates,        // cache of already loaded templates, avoids
+                               // multiple SQL queries for the same string
+           $mTemplatePath;     // stores an unsorted hash of all the templates already loaded
+                               // in this path. Used for loop detection.
 
        function Parser() {
+               $this->mTemplates = array();
+               $this->mTemplatePath = array();
                $this->mTagHooks = array();
                $this->clearState();
        }
@@ -1445,6 +1452,10 @@ class Parser
        /* private */ function replaceVariables( $text, $args = array() ) {
                global $wgLang, $wgScript, $wgArticlePath;
 
+                # Prevent to big inclusions
+                if(strlen($text)> MAX_INCLUDE_SIZE)
+                   return $text;
+
                $fname = 'Parser::replaceVariables';
                wfProfileIn( $fname );
 
@@ -1612,14 +1623,22 @@ class Parser
                        $found = true;
                        $this->mOutput->mContainsOldMagic = true;
                }
-/*
-               # Arguments input from the caller
-               $inputArgs = end( $this->mArgStack );
-               if ( !$found && array_key_exists( $part1, $inputArgs ) ) {
-                       $text = $inputArgs[$part1];
+
+                # Template table test
+
+               # Did we encounter this template already? If yes, it is in the cache
+               # and we need to check for loops.
+               if ( isset( $this->mTemplates[$part1] ) ) {
+                       # Infinite loop test
+                       if ( isset( $this->mTemplatePath[$part1] ) ) {
+                               $noparse = true;
+                               $found = true;
+                       }                  
+                       # set $text to cached message.
+                       $text = $this->mTemplates[$part1];
                        $found = true;
                }
-*/
+
                # Load from database
                if ( !$found ) {
                        $title = Title::newFromText( $part1, NS_TEMPLATE );
@@ -1627,6 +1646,7 @@ class Parser
                                # Check for excessive inclusion
                                $dbk = $title->getPrefixedDBkey();
                                if ( $this->incrementIncludeCount( $dbk ) ) {
+                                       # This should never be reached.
                                        $article = new Article( $title );
                                        $articleContent = $article->getContentWithoutUsingSoManyDamnGlobals();
                                        if ( $articleContent !== false ) {
@@ -1641,6 +1661,9 @@ class Parser
                                        $text = '[[' . $title->getPrefixedText() . ']]';
                                        $found = true;
                                }
+
+                                # Template cache array insertion
+                               $this->mTemplates[$part1] = $text;
                        }
                }
 
@@ -1673,6 +1696,9 @@ class Parser
                                $wgLinkCache->suspend();
                        }
 
+                        # Add a new element to the templace recursion path
+                       $this->mTemplatePath[$part1] = 1;
+
                        # Run full parser on the included text
                        $text = $this->stripParse( $text, $newline, $assocArgs );
 
@@ -1682,6 +1708,8 @@ class Parser
                                $wgLinkCache->addLinkObj( $title );
                        }
                }
+                # Empties the template path
+                $this->mTemplatePath = array();
 
                if ( !$found ) {
                        return $matches[0];