mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/AbuseFilter.git
synced 2024-12-03 01:56:28 +00:00
d51ca862c6
IMHO these can be considered unit tests; they were already fast, but now they're executed in an instant. This requires several changes: 1 - delay retrieving messages in AFPUserVisibleException, to avoid having to deal with i18n whenever we want to test exceptions; 2 - Use some DI for Parser and Tokenizer. Equivset-dependend tests are also moved to a new class, thus helping to fix the AF part of T189560. Change-Id: If4585bf9bb696857005cf40a0d6985c36ac7e7a8
403 lines
13 KiB
PHP
403 lines
13 KiB
PHP
<?php
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/**
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* AbuseFilterCachingParser is the version of AbuseFilterParser which parses
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* the code into an abstract syntax tree before evaluating it, and caches that
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* tree.
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*
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* It currently inherits AbuseFilterParser in order to avoid code duplication.
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* In future, this code will replace current AbuseFilterParser entirely.
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*
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* @todo Override checkSyntax and make it only try to build the AST. That would mean faster results,
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* and no need to mess with DUNDEFINED and the like. However, we must first try to reduce the
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* amount of runtime-only exceptions, and try to detect them in the AFPTreeParser instead.
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* Otherwise, people may be able to save a broken filter without the syntax check reporting that.
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*/
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class AbuseFilterCachingParser extends AbuseFilterParser {
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const CACHE_VERSION = 1;
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/**
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* Return the generated version of the parser for cache invalidation
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* purposes. Automatically tracks list of all functions and invalidates the
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* cache if it is changed.
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* @return string
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*/
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public static function getCacheVersion() {
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static $version = null;
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if ( $version !== null ) {
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return $version;
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}
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$versionKey = [
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self::CACHE_VERSION,
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AFPTreeParser::CACHE_VERSION,
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AbuseFilterTokenizer::CACHE_VERSION,
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array_keys( AbuseFilterParser::$mFunctions ),
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array_keys( AbuseFilterParser::$mKeywords ),
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];
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$version = hash( 'sha256', serialize( $versionKey ) );
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return $version;
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}
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/**
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* Resets the state of the parser
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*/
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public function resetState() {
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$this->mVariables = new AbuseFilterVariableHolder;
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$this->mCur = new AFPToken();
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$this->mCondCount = 0;
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}
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/**
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* @param string $code
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* @return AFPData
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*/
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public function intEval( $code ) : AFPData {
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$tree = $this->getTree( $code );
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$res = $this->evalTree( $tree );
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if ( $res->getType() === AFPData::DUNDEFINED ) {
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$res = new AFPData( AFPData::DBOOL, false );
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}
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return $res;
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}
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/**
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* @param string $code
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* @return AFPSyntaxTree
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*/
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private function getTree( $code ) : AFPSyntaxTree {
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return $this->cache->getWithSetCallback(
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$this->cache->makeGlobalKey(
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__CLASS__,
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self::getCacheVersion(),
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hash( 'sha256', $code )
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),
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BagOStuff::TTL_DAY,
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function () use ( $code ) {
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$parser = new AFPTreeParser( $this->cache, $this->logger );
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$parser->setFilter( $this->mFilter );
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return $parser->parse( $code );
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}
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);
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}
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/**
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* @param AFPSyntaxTree $tree
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* @return AFPData
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*/
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private function evalTree( AFPSyntaxTree $tree ) : AFPData {
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$root = $tree->getRoot();
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if ( !$root ) {
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return new AFPData( AFPData::DNULL );
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}
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return $this->evalNode( $root );
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}
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/**
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* Evaluate the value of the specified AST node.
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*
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* @param AFPTreeNode $node The node to evaluate.
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* @return AFPData|AFPTreeNode|string
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* @throws AFPException
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* @throws AFPUserVisibleException
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* @throws MWException
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*/
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private function evalNode( AFPTreeNode $node ) {
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// A lot of AbuseFilterParser features rely on $this->mCur->pos or
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// $this->mPos for error reporting.
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// FIXME: this is a hack which needs to be removed when the parsers are merged.
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$this->mPos = $node->position;
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$this->mCur->pos = $node->position;
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switch ( $node->type ) {
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case AFPTreeNode::ATOM:
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$tok = $node->children;
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switch ( $tok->type ) {
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case AFPToken::TID:
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return $this->getVarValue( strtolower( $tok->value ) );
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case AFPToken::TSTRING:
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return new AFPData( AFPData::DSTRING, $tok->value );
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case AFPToken::TFLOAT:
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return new AFPData( AFPData::DFLOAT, $tok->value );
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case AFPToken::TINT:
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return new AFPData( AFPData::DINT, $tok->value );
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/** @noinspection PhpMissingBreakStatementInspection */
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case AFPToken::TKEYWORD:
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switch ( $tok->value ) {
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case "true":
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return new AFPData( AFPData::DBOOL, true );
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case "false":
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return new AFPData( AFPData::DBOOL, false );
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case "null":
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return new AFPData( AFPData::DNULL );
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}
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// Fallthrough intended
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default:
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// @codeCoverageIgnoreStart
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throw new AFPException( "Unknown token provided in the ATOM node" );
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// @codeCoverageIgnoreEnd
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}
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case AFPTreeNode::ARRAY_DEFINITION:
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$items = array_map( [ $this, 'evalNode' ], $node->children );
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return new AFPData( AFPData::DARRAY, $items );
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case AFPTreeNode::FUNCTION_CALL:
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$functionName = $node->children[0];
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$args = array_slice( $node->children, 1 );
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$dataArgs = array_map( [ $this, 'evalNode' ], $args );
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return $this->callFunc( $functionName, $dataArgs );
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case AFPTreeNode::ARRAY_INDEX:
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list( $array, $offset ) = $node->children;
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$array = $this->evalNode( $array );
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if ( $array->getType() === AFPData::DUNDEFINED ) {
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return new AFPData( AFPData::DUNDEFINED );
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}
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if ( $array->getType() !== AFPData::DARRAY ) {
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throw new AFPUserVisibleException( 'notarray', $node->position, [] );
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}
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$offset = $this->evalNode( $offset )->toInt();
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$array = $array->toArray();
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if ( count( $array ) <= $offset ) {
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throw new AFPUserVisibleException( 'outofbounds', $node->position,
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[ $offset, count( $array ) ] );
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}
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return $array[$offset];
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case AFPTreeNode::UNARY:
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list( $operation, $argument ) = $node->children;
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$argument = $this->evalNode( $argument );
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if ( $operation === '-' ) {
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return $argument->unaryMinus();
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}
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return $argument;
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case AFPTreeNode::KEYWORD_OPERATOR:
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list( $keyword, $leftOperand, $rightOperand ) = $node->children;
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$func = self::$mKeywords[$keyword];
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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if (
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$leftOperand->getType() === AFPData::DUNDEFINED ||
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$rightOperand->getType() === AFPData::DUNDEFINED
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) {
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$result = new AFPData( AFPData::DUNDEFINED );
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} else {
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$this->raiseCondCount();
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// @phan-suppress-next-line PhanParamTooMany Not every function needs the position
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$result = $this->$func( $leftOperand, $rightOperand, $node->position );
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}
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return $result;
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case AFPTreeNode::BOOL_INVERT:
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list( $argument ) = $node->children;
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$argument = $this->evalNode( $argument );
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return $argument->boolInvert();
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case AFPTreeNode::POW:
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list( $base, $exponent ) = $node->children;
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$base = $this->evalNode( $base );
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$exponent = $this->evalNode( $exponent );
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return $base->pow( $exponent );
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case AFPTreeNode::MUL_REL:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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return $leftOperand->mulRel( $rightOperand, $op, $node->position );
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case AFPTreeNode::SUM_REL:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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switch ( $op ) {
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case '+':
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return $leftOperand->sum( $rightOperand );
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case '-':
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return $leftOperand->sub( $rightOperand );
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default:
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// @codeCoverageIgnoreStart
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throw new AFPException( "Unknown sum-related operator: {$op}" );
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// @codeCoverageIgnoreEnd
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}
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case AFPTreeNode::COMPARE:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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$this->raiseCondCount();
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return $leftOperand->compareOp( $rightOperand, $op );
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case AFPTreeNode::LOGIC:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$value = $leftOperand->getType() === AFPData::DUNDEFINED ? false : $leftOperand->toBool();
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// Short-circuit.
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if ( ( !$value && $op === '&' ) || ( $value && $op === '|' ) ) {
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if ( $rightOperand instanceof AFPTreeNode ) {
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$this->discardWithHoisting( $rightOperand );
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}
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return $leftOperand;
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}
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$rightOperand = $this->evalNode( $rightOperand );
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return $leftOperand->boolOp( $rightOperand, $op );
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case AFPTreeNode::CONDITIONAL:
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list( $condition, $valueIfTrue, $valueIfFalse ) = $node->children;
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$condition = $this->evalNode( $condition );
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if ( $condition->toBool() ) {
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if ( $valueIfFalse !== null ) {
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$this->discardWithHoisting( $valueIfFalse );
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}
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return $this->evalNode( $valueIfTrue );
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} else {
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$this->discardWithHoisting( $valueIfTrue );
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return $valueIfFalse !== null
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? $this->evalNode( $valueIfFalse )
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// We assume null as default if the else is missing
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: new AFPData( AFPData::DNULL );
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}
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case AFPTreeNode::ASSIGNMENT:
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list( $varName, $value ) = $node->children;
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$value = $this->evalNode( $value );
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$this->setUserVariable( $varName, $value );
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return $value;
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case AFPTreeNode::INDEX_ASSIGNMENT:
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list( $varName, $offset, $value ) = $node->children;
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if ( $this->isBuiltinVar( $varName ) ) {
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throw new AFPUserVisibleException( 'overridebuiltin', $node->position, [ $varName ] );
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} elseif ( !$this->mVariables->varIsSet( $varName ) ) {
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throw new AFPUserVisibleException( 'unrecognisedvar', $node->position, [ $varName ] );
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}
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$array = $this->mVariables->getVar( $varName );
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$value = $this->evalNode( $value );
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if ( $array->getType() !== AFPData::DUNDEFINED ) {
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// If it's a DUNDEFINED, leave it as is
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if ( $array->getType() !== AFPData::DARRAY ) {
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throw new AFPUserVisibleException( 'notarray', $node->position, [] );
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}
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$offset = $this->evalNode( $offset )->toInt();
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$array = $array->toArray();
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if ( count( $array ) <= $offset ) {
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throw new AFPUserVisibleException( 'outofbounds', $node->position,
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[ $offset, count( $array ) ] );
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}
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$array[$offset] = $value;
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$this->setUserVariable( $varName, new AFPData( AFPData::DARRAY, $array ) );
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}
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return $value;
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case AFPTreeNode::ARRAY_APPEND:
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list( $varName, $value ) = $node->children;
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if ( $this->isBuiltinVar( $varName ) ) {
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throw new AFPUserVisibleException( 'overridebuiltin', $node->position, [ $varName ] );
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} elseif ( !$this->mVariables->varIsSet( $varName ) ) {
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throw new AFPUserVisibleException( 'unrecognisedvar', $node->position, [ $varName ] );
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}
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$array = $this->mVariables->getVar( $varName );
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if ( $array->getType() !== AFPData::DUNDEFINED ) {
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// If it's a DUNDEFINED, leave it as is
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if ( $array->getType() !== AFPData::DARRAY ) {
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throw new AFPUserVisibleException( 'notarray', $node->position, [] );
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}
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$array = $array->toArray();
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$array[] = $this->evalNode( $value );
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$this->setUserVariable( $varName, new AFPData( AFPData::DARRAY, $array ) );
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}
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return $value;
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case AFPTreeNode::SEMICOLON:
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$lastValue = null;
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// @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach children is array here
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foreach ( $node->children as $statement ) {
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$lastValue = $this->evalNode( $statement );
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}
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return $lastValue;
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default:
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// @codeCoverageIgnoreStart
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throw new AFPException( "Unknown node type passed: {$node->type}" );
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// @codeCoverageIgnoreEnd
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}
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}
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/**
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* Intended to be used for short-circuit as a solution for T214674.
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* Given a node, check it and its children; if there are assignments of non-existing variables,
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* hoist them. In case of index assignment or array append, the old value is always erased and
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* overwritten with a DUNDEFINED. This is used to allow stuff like:
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* false & ( var := 'foo' ); var == 2
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* or
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* if ( false ) then ( var := 'foo' ) else ( 1 ) end; var == 2
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* where `false` is something evaluated as false at runtime.
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* In the future, we may decide to always throw in those cases (for stability and parser speed),
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* but that's not good, at least as long as people don't have an on-wiki way to see if filters
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* are failing at runtime.
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* @todo Decide about that.
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*
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* @param AFPTreeNode $node
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*/
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private function discardWithHoisting( AFPTreeNode $node ) {
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if (
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$node->type === AFPTreeNode::ASSIGNMENT &&
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!$this->mVariables->varIsSet( $node->children[0] )
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) {
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$this->setUserVariable( $node->children[0], new AFPData( AFPData::DUNDEFINED ) );
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} elseif (
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$node->type === AFPTreeNode::INDEX_ASSIGNMENT ||
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$node->type === AFPTreeNode::ARRAY_APPEND
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) {
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$varName = $node->children[0];
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if ( !$this->mVariables->varIsSet( $varName ) ) {
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throw new AFPUserVisibleException( 'unrecognisedvar', $node->position, [ $varName ] );
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}
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$this->setUserVariable( $varName, new AFPData( AFPData::DUNDEFINED ) );
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} elseif (
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$node->type === AFPTreeNode::FUNCTION_CALL &&
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in_array( $node->children[0], [ 'set', 'set_var' ] ) &&
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isset( $node->children[1] )
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) {
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$varnameNode = $node->children[1];
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if ( $varnameNode->type !== AFPTreeNode::ATOM ) {
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// Shouldn't happen since variable variables are not allowed
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throw new AFPException( "Got non-atom type {$varnameNode->type} for set_var" );
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}
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$varname = $varnameNode->children->value;
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if ( !$this->mVariables->varIsSet( $varname ) ) {
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$this->setUserVariable( $varname, new AFPData( AFPData::DUNDEFINED ) );
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}
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} elseif ( $node->type === AFPTreeNode::ATOM ) {
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return;
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}
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// @phan-suppress-next-line PhanTypeSuspiciousNonTraversableForeach ATOM case excluded above
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foreach ( $node->children as $child ) {
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if ( $child instanceof AFPTreeNode ) {
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$this->discardWithHoisting( $child );
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}
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}
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}
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}
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