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| 1 | <?php declare( strict_types=1 ); |
| 2 | |
| 3 | namespace SecurityCheckPlugin; |
| 4 | |
| 5 | use ast\Node; |
| 6 | use Closure; |
| 7 | use Exception; |
| 8 | use Generator; |
| 9 | use Phan\AST\ASTReverter; |
| 10 | use Phan\AST\ContextNode; |
| 11 | use Phan\AST\UnionTypeVisitor; |
| 12 | use Phan\BlockAnalysisVisitor; |
| 13 | use Phan\CodeBase; |
| 14 | use Phan\Debug; |
| 15 | use Phan\Exception\CodeBaseException; |
| 16 | use Phan\Exception\FQSENException; |
| 17 | use Phan\Exception\IssueException; |
| 18 | use Phan\Exception\NodeException; |
| 19 | use Phan\Exception\UnanalyzableException; |
| 20 | use Phan\Issue; |
| 21 | use Phan\Language\Context; |
| 22 | use Phan\Language\Element\FunctionInterface; |
| 23 | use Phan\Language\Element\GlobalVariable; |
| 24 | use Phan\Language\Element\Method; |
| 25 | use Phan\Language\Element\PassByReferenceVariable; |
| 26 | use Phan\Language\Element\Property; |
| 27 | use Phan\Language\Element\TypedElementInterface; |
| 28 | use Phan\Language\Element\Variable; |
| 29 | use Phan\Language\FQSEN\FullyQualifiedClassName; |
| 30 | use Phan\Language\FQSEN\FullyQualifiedFunctionLikeName; |
| 31 | use Phan\Language\FQSEN\FullyQualifiedFunctionName; |
| 32 | use Phan\Language\FQSEN\FullyQualifiedMethodName; |
| 33 | use Phan\Language\Type\GenericArrayType; |
| 34 | use Phan\Language\Type\LiteralTypeInterface; |
| 35 | use Phan\Language\UnionType; |
| 36 | |
| 37 | /** |
| 38 | * Trait for the Tainedness visitor subclasses. Mostly contains |
| 39 | * utility methods. |
| 40 | * |
| 41 | * Copyright (C) 2017 Brian Wolff <bawolff@gmail.com> |
| 42 | * |
| 43 | * This program is free software; you can redistribute it and/or modify |
| 44 | * it under the terms of the GNU General Public License as published by |
| 45 | * the Free Software Foundation; either version 2 of the License, or |
| 46 | * (at your option) any later version. |
| 47 | * |
| 48 | * This program is distributed in the hope that it will be useful, |
| 49 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 50 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 51 | * GNU General Public License for more details. |
| 52 | * |
| 53 | * You should have received a copy of the GNU General Public License along |
| 54 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 55 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 56 | */ |
| 57 | /** |
| 58 | * @property-read Context $context |
| 59 | * @property-read \Phan\CodeBase $code_base |
| 60 | */ |
| 61 | trait TaintednessBaseVisitor { |
| 62 | use TaintednessAccessorsTrait; |
| 63 | |
| 64 | /** @var null|string|bool|resource filehandle to output debug messages */ |
| 65 | private $debugOutput; |
| 66 | |
| 67 | /** @var Context|null Override the file/line number to emit issues */ |
| 68 | protected $overrideContext; |
| 69 | |
| 70 | /** |
| 71 | * @var bool[] FQSENs of classes without __toString, map of [ (string)FQSEN => true ] |
| 72 | */ |
| 73 | protected static $fqsensWithoutToStringCache = []; |
| 74 | |
| 75 | /** |
| 76 | * Merge taintedness of a function/method |
| 77 | * |
| 78 | * @param FunctionInterface $func |
| 79 | * @param FunctionTaintedness $taint |
| 80 | */ |
| 81 | protected function addFuncTaint( FunctionInterface $func, FunctionTaintedness $taint ): void { |
| 82 | $curTaint = self::getFuncTaint( $func ); |
| 83 | if ( $curTaint ) { |
| 84 | $newTaint = $curTaint->asMergedWith( $taint ); |
| 85 | } else { |
| 86 | $newTaint = $taint; |
| 87 | } |
| 88 | self::doSetFuncTaint( $func, $newTaint ); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Ensure a function-like has its taintedness set and not unknown |
| 93 | * |
| 94 | * @param FunctionInterface $func |
| 95 | */ |
| 96 | protected function ensureFuncTaintIsSet( FunctionInterface $func ): void { |
| 97 | if ( !self::getFuncTaint( $func ) ) { |
| 98 | self::doSetFuncTaint( $func, new FunctionTaintedness( Taintedness::newSafe() ) ); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * @param FunctionInterface $func |
| 104 | * @param Context|string|null $reason To override the caused-by line |
| 105 | * @param FunctionTaintedness $addedTaint |
| 106 | * @param FunctionTaintedness $allNewTaint |
| 107 | * @param MethodLinks|null $returnLinks NOTE: These are only used for preserved params, since for sink params |
| 108 | * we're already adding a Taintedness with the expected EXEC bits. |
| 109 | */ |
| 110 | private function maybeAddFuncError( |
| 111 | FunctionInterface $func, |
| 112 | $reason, |
| 113 | FunctionTaintedness $addedTaint, |
| 114 | FunctionTaintedness $allNewTaint, |
| 115 | MethodLinks $returnLinks = null |
| 116 | ): void { |
| 117 | if ( !is_string( $reason ) ) { |
| 118 | $newErrors = [ $this->dbgInfo( $reason ?? $this->context ) ]; |
| 119 | } else { |
| 120 | $newErrors = [ $reason ]; |
| 121 | } |
| 122 | if ( $this->overrideContext && !( $this->isHook ?? false ) ) { |
| 123 | // @phan-suppress-previous-line PhanUndeclaredProperty |
| 124 | $newErrors[] = $this->dbgInfo( $this->overrideContext ); |
| 125 | } |
| 126 | |
| 127 | $hasReturnLinks = $returnLinks && !$returnLinks->isEmpty(); |
| 128 | |
| 129 | // Future TODO: we might consider using PreservedTaintedness from the funcs instead of MethodLinks, but using |
| 130 | // links is more consistent with what we do for non-function causedby lines. |
| 131 | |
| 132 | $newErr = self::getFuncCausedByRawCloneOrEmpty( $func ); |
| 133 | |
| 134 | foreach ( $addedTaint->getSinkParamKeysNoVariadic() as $key ) { |
| 135 | if ( $reason || $allNewTaint->canOverrideNonVariadicParam( $key ) ) { |
| 136 | $curTaint = $addedTaint->getParamSinkTaint( $key ); |
| 137 | if ( $curTaint->has( SecurityCheckPlugin::ALL_EXEC_TAINT ) ) { |
| 138 | $newErr->addParamSinkLines( $key, $newErrors, $curTaint->asExecToYesTaint() ); |
| 139 | } |
| 140 | } |
| 141 | } |
| 142 | foreach ( $addedTaint->getPreserveParamKeysNoVariadic() as $key ) { |
| 143 | if ( $hasReturnLinks && ( $reason || $allNewTaint->canOverrideNonVariadicParam( $key ) ) ) { |
| 144 | $newErr->addParamPreservedLines( |
| 145 | $key, |
| 146 | $newErrors, |
| 147 | Taintedness::newSafe(), |
| 148 | $returnLinks->asFilteredForFuncAndParam( $func, $key ) |
| 149 | ); |
| 150 | } |
| 151 | } |
| 152 | $variadicIndex = $addedTaint->getVariadicParamIndex(); |
| 153 | if ( $variadicIndex !== null && ( $reason || $allNewTaint->canOverrideVariadicParam() ) ) { |
| 154 | $sinkVariadic = $addedTaint->getVariadicParamSinkTaint(); |
| 155 | if ( $sinkVariadic && $sinkVariadic->has( SecurityCheckPlugin::ALL_EXEC_TAINT ) ) { |
| 156 | $newErr->addVariadicParamSinkLines( |
| 157 | $variadicIndex, |
| 158 | $newErrors, |
| 159 | $sinkVariadic->asExecToYesTaint() |
| 160 | ); |
| 161 | } |
| 162 | if ( $hasReturnLinks ) { |
| 163 | $newErr->addVariadicParamPreservedLines( |
| 164 | $variadicIndex, |
| 165 | $newErrors, |
| 166 | Taintedness::newSafe(), |
| 167 | $returnLinks->asFilteredForFuncAndParam( $func, $variadicIndex ) |
| 168 | ); |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | $curTaint = $addedTaint->getOverall(); |
| 173 | if ( ( $reason || $allNewTaint->canOverrideOverall() ) && $curTaint->has( SecurityCheckPlugin::ALL_TAINT ) ) { |
| 174 | // Note, the generic error shouldn't have any link |
| 175 | $newErr->addGenericLines( $newErrors, $curTaint ); |
| 176 | } |
| 177 | |
| 178 | self::setFuncCausedByRaw( $func, $newErr ); |
| 179 | } |
| 180 | |
| 181 | /** |
| 182 | * Add the given caused-by lines to $element. |
| 183 | * |
| 184 | * @param TypedElementInterface $element |
| 185 | * @param CausedByLines $rightError |
| 186 | */ |
| 187 | protected function mergeTaintError( TypedElementInterface $element, CausedByLines $rightError ): void { |
| 188 | assert( !$element instanceof FunctionInterface, 'Should use mergeFuncTaintError' ); |
| 189 | |
| 190 | $curError = self::getCausedByRaw( $element ); |
| 191 | |
| 192 | if ( !$curError ) { |
| 193 | $newLeftError = $rightError; |
| 194 | } else { |
| 195 | $newLeftError = $curError->asMergedWith( $rightError ); |
| 196 | } |
| 197 | |
| 198 | self::setCausedByRaw( $element, $newLeftError ); |
| 199 | } |
| 200 | |
| 201 | /** |
| 202 | * @param FunctionInterface $func |
| 203 | * @param FunctionCausedByLines $newError |
| 204 | * @param FunctionTaintedness $allFuncTaint Used to check NO_OVERRIDE |
| 205 | */ |
| 206 | protected function mergeFuncError( |
| 207 | FunctionInterface $func, |
| 208 | FunctionCausedByLines $newError, |
| 209 | FunctionTaintedness $allFuncTaint |
| 210 | ): void { |
| 211 | $funcError = self::getFuncCausedByRawCloneOrEmpty( $func ); |
| 212 | $funcError->mergeWith( $newError, $allFuncTaint ); |
| 213 | self::setFuncCausedByRaw( $func, $funcError ); |
| 214 | } |
| 215 | |
| 216 | /** |
| 217 | * Add the current context to taintedOriginalError book-keeping |
| 218 | * |
| 219 | * This allows us to show users what line caused an issue. |
| 220 | * |
| 221 | * @param TypedElementInterface $elem Where to put it |
| 222 | * @param Taintedness $taintedness |
| 223 | * @param MethodLinks|null $links |
| 224 | * @param string|null $reason To override the caused by line |
| 225 | */ |
| 226 | protected function addTaintError( |
| 227 | TypedElementInterface $elem, |
| 228 | Taintedness $taintedness, |
| 229 | ?MethodLinks $links, |
| 230 | string $reason = null |
| 231 | ): void { |
| 232 | assert( !$elem instanceof FunctionInterface, 'Should use addFuncTaintError' ); |
| 233 | |
| 234 | if ( !$taintedness->has( SecurityCheckPlugin::ALL_TAINT ) && ( !$links || $links->isEmpty() ) ) { |
| 235 | // Don't add book-keeping if no actual taint was added. |
| 236 | return; |
| 237 | } |
| 238 | |
| 239 | $newErrors = $reason !== null ? [ $reason ] : [ $this->dbgInfo() ]; |
| 240 | if ( $this->overrideContext && !( $this->isHook ?? false ) ) { |
| 241 | // @phan-suppress-previous-line PhanUndeclaredProperty |
| 242 | $newErrors[] = $this->dbgInfo( $this->overrideContext ); |
| 243 | } |
| 244 | |
| 245 | $newErr = self::getCausedByRawCloneOrEmpty( $elem ); |
| 246 | $newErr->addLines( $newErrors, $taintedness, $links ); |
| 247 | self::setCausedByRaw( $elem, $newErr ); |
| 248 | } |
| 249 | |
| 250 | /** |
| 251 | * Ensures that the given variable obj has some taintedness set, initializing to safe if it doesn't. |
| 252 | * |
| 253 | * @param TypedElementInterface $varObj |
| 254 | */ |
| 255 | protected function ensureTaintednessIsSet( TypedElementInterface $varObj ): void { |
| 256 | if ( !self::getTaintednessRaw( $varObj ) ) { |
| 257 | self::setTaintednessRaw( $varObj, Taintedness::newSafe() ); |
| 258 | } |
| 259 | if ( $varObj instanceof GlobalVariable ) { |
| 260 | $gVarObj = $varObj->getElement(); |
| 261 | if ( !self::getTaintednessRaw( $gVarObj ) ) { |
| 262 | self::setTaintednessRaw( $gVarObj, Taintedness::newSafe() ); |
| 263 | } |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | /** |
| 268 | * Change the taintedness of $variableObj. |
| 269 | * |
| 270 | * @param TypedElementInterface $variableObj |
| 271 | * @param Taintedness $taintedness |
| 272 | * @param bool $override |
| 273 | */ |
| 274 | private function setTaintedness( |
| 275 | TypedElementInterface $variableObj, |
| 276 | Taintedness $taintedness, |
| 277 | bool $override |
| 278 | ): void { |
| 279 | assert( !$variableObj instanceof FunctionInterface, 'Must use setFuncTaint for functions' ); |
| 280 | |
| 281 | if ( |
| 282 | $variableObj instanceof Property && |
| 283 | $variableObj->getClassFQSEN() === FullyQualifiedClassName::getStdClassFQSEN() |
| 284 | ) { |
| 285 | // Phan conflates all stdClass props, see https://github.com/phan/phan/issues/3869 |
| 286 | // Avoid doing the same with taintedness, as that would cause weird issues (see |
| 287 | // 'stdclassconflation' test). |
| 288 | // TODO Is it possible to store prop taintedness in the Variable object? |
| 289 | // that would be similar to a fine-grained handling of arrays. |
| 290 | return; |
| 291 | } |
| 292 | |
| 293 | if ( $override ) { |
| 294 | $newTaint = $taintedness; |
| 295 | } else { |
| 296 | $curTaint = self::getTaintednessRaw( $variableObj ); |
| 297 | if ( !$curTaint ) { |
| 298 | $newTaint = $taintedness; |
| 299 | } else { |
| 300 | // NOTE: Do NOT merge in place here, as that would change the taintedness for all variable |
| 301 | // objects of which $variableObj is a clone! |
| 302 | $newTaint = $curTaint->asMergedWith( $taintedness ); |
| 303 | } |
| 304 | } |
| 305 | self::setTaintednessRaw( $variableObj, $newTaint ); |
| 306 | } |
| 307 | |
| 308 | /** |
| 309 | * Given a func, if it has a defining func different from itself, return that defining func. Returns null otherwise. |
| 310 | * |
| 311 | * @param FunctionInterface $func |
| 312 | * @return FunctionInterface|null |
| 313 | */ |
| 314 | private function getDefiningFuncIfDifferent( FunctionInterface $func ): ?FunctionInterface { |
| 315 | if ( $func instanceof Method && $func->hasDefiningFQSEN() ) { |
| 316 | $definingFQSEN = $func->getDefiningFQSEN(); |
| 317 | if ( $definingFQSEN !== $func->getFQSEN() ) { |
| 318 | return $this->code_base->getMethodByFQSEN( $definingFQSEN ); |
| 319 | } |
| 320 | } |
| 321 | return null; |
| 322 | } |
| 323 | |
| 324 | /** |
| 325 | * Get a list of places to look for function taint info |
| 326 | * |
| 327 | * @todo How to handle multiple function definitions (phan "alternates") |
| 328 | * @param FunctionInterface $func |
| 329 | * @return Generator<FunctionInterface> |
| 330 | */ |
| 331 | private function getPossibleFuncDefinitions( FunctionInterface $func ): Generator { |
| 332 | yield $func; |
| 333 | |
| 334 | // If we don't have a defining func, stay with the same func. |
| 335 | // definingFunc is used later on during fallback processing. |
| 336 | $definingFunc = $this->getDefiningFuncIfDifferent( $func ); |
| 337 | if ( $definingFunc ) { |
| 338 | yield $definingFunc; |
| 339 | } |
| 340 | if ( $func instanceof Method ) { |
| 341 | try { |
| 342 | $class = $func->getClass( $this->code_base ); |
| 343 | } catch ( CodeBaseException $e ) { |
| 344 | $this->debug( __METHOD__, "Class not found for func $func: " . $this->getDebugInfo( $e ) ); |
| 345 | return; |
| 346 | } |
| 347 | |
| 348 | // Iterate through the whole hierarchy to see if the method was defined in an interface or trait. A few |
| 349 | // notes on this: |
| 350 | // - getNonParentAncestorFQSENList (and similar methods in Class and Method) only go one level up, and |
| 351 | // would not give us e.g. the interfaces implemented by the parent class. |
| 352 | // - asExpandedTypes would work, but it has a non-zero overhead, and most importantly, we would cause phan |
| 353 | // to emit issues like RedefinedClass in places where phan wouldn't normally emit them. |
| 354 | // - It's unclear whether this code should also look for method definitions in classes (and not just |
| 355 | // interfaces/traits). And more generally, what would the expectations for *-taint annotations be. |
| 356 | $curClass = $class; |
| 357 | // Use a safeguard in case this goes out of control (e.g., broken code with circular inheritance). |
| 358 | $depth = 0; |
| 359 | do { |
| 360 | $depth++; |
| 361 | $nonParents = $curClass->getNonParentAncestorFQSENList(); |
| 362 | |
| 363 | foreach ( $nonParents as $nonParentFQSEN ) { |
| 364 | if ( $this->code_base->hasClassWithFQSEN( $nonParentFQSEN ) ) { |
| 365 | $nonParent = $this->code_base->getClassByFQSEN( $nonParentFQSEN ); |
| 366 | // TODO Assuming this is a direct invocation, but it doesn't always make sense |
| 367 | $directInvocation = true; |
| 368 | if ( $nonParent->hasMethodWithName( $this->code_base, $func->getName(), $directInvocation ) ) { |
| 369 | yield $nonParent->getMethodByName( $this->code_base, $func->getName() ); |
| 370 | } |
| 371 | } |
| 372 | } |
| 373 | if ( |
| 374 | !$curClass->hasParentType() || |
| 375 | !$this->code_base->hasClassWithFQSEN( $curClass->getParentClassFQSEN() ) |
| 376 | ) { |
| 377 | break; |
| 378 | } |
| 379 | $curClass = $curClass->getParentClass( $this->code_base ); |
| 380 | } while ( $depth < 20 ); |
| 381 | } |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * This is also for methods and other function like things |
| 386 | * @note This is not guaranteed to return a clone |
| 387 | * |
| 388 | * @param FunctionInterface $func What function/method to look up |
| 389 | * @return FunctionTaintedness Always a clone |
| 390 | */ |
| 391 | protected function getTaintOfFunction( FunctionInterface $func ): FunctionTaintedness { |
| 392 | $funcTaint = self::getFuncTaint( $func ); |
| 393 | if ( $funcTaint !== null ) { |
| 394 | return $funcTaint; |
| 395 | } |
| 396 | |
| 397 | $annotatedTaint = $this->getSetKnownTaintOfFunctionWithoutAnalysis( $func ); |
| 398 | if ( $annotatedTaint ) { |
| 399 | return $annotatedTaint; |
| 400 | } |
| 401 | |
| 402 | $isPHPInternalFunc = $func->isPHPInternal(); |
| 403 | if ( !$isPHPInternalFunc ) { |
| 404 | // PHP internal functions cannot be analyzed because they don't have a body. |
| 405 | $funcToAnalyze = $this->getDefiningFuncIfDifferent( $func ) ?: $func; |
| 406 | $this->analyzeFunc( $funcToAnalyze ); |
| 407 | $analyzedFuncTaint = self::getFuncTaint( $funcToAnalyze ); |
| 408 | if ( $analyzedFuncTaint !== null ) { |
| 409 | return $analyzedFuncTaint; |
| 410 | } |
| 411 | } |
| 412 | |
| 413 | $taintFromReturnType = $this->getTaintByType( $func->getUnionType() ); |
| 414 | if ( !$isPHPInternalFunc ) { |
| 415 | // If we haven't seen this function before, first of all check the return type. If it |
| 416 | // returns a safe type (like int), it's safe. |
| 417 | $taint = new FunctionTaintedness( $taintFromReturnType ); |
| 418 | self::doSetFuncTaint( $func, $taint ); |
| 419 | $this->maybeAddFuncError( $func, null, $taint, $taint ); |
| 420 | } else { |
| 421 | // Assume that anything really dangerous we've already hardcoded. So just preserve taint. |
| 422 | $overall = $taintFromReturnType->isSafe() |
| 423 | ? $taintFromReturnType |
| 424 | : new Taintedness( SecurityCheckPlugin::PRESERVE_TAINT ); |
| 425 | $taint = new FunctionTaintedness( $overall ); |
| 426 | // We're not adding any error here, since it's presumably unnecessary for PHP internal stuff. |
| 427 | self::doSetFuncTaint( $func, $taint ); |
| 428 | } |
| 429 | return $taint; |
| 430 | } |
| 431 | |
| 432 | /** |
| 433 | * Given a function, find out if it has any hardcoded/annotated taint, or whether it should inherit its taint |
| 434 | * from an alternate definition. If anything was found, set that taintedness in the func object and return it. |
| 435 | * In particular, this does NOT cause $func to be analyzed. |
| 436 | * |
| 437 | * @param FunctionInterface $func |
| 438 | * @return FunctionTaintedness|null |
| 439 | */ |
| 440 | private function getSetKnownTaintOfFunctionWithoutAnalysis( FunctionInterface $func ): ?FunctionTaintedness { |
| 441 | $funcsToTry = $this->getPossibleFuncDefinitions( $func ); |
| 442 | foreach ( $funcsToTry as $trialFunc ) { |
| 443 | /** @var FunctionInterface $trialFunc */ |
| 444 | if ( !$trialFunc->isPHPInternal() ) { |
| 445 | // PHP internal functions can't have a docblock. |
| 446 | $taintData = $this->getDocBlockTaintOfFunc( $trialFunc ); |
| 447 | if ( $taintData !== null ) { |
| 448 | [ $taint, $methodLinks ] = $taintData; |
| 449 | self::doSetFuncTaint( $func, $taint ); |
| 450 | // TODO Make this more granular if possible |
| 451 | $errorDesc = 'annotations in ' . $trialFunc->getFQSEN()->__toString(); |
| 452 | $this->maybeAddFuncError( $func, $errorDesc, $taint, $taint, $methodLinks ); |
| 453 | return $taint; |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | $trialFuncName = $trialFunc->getFQSEN(); |
| 458 | $taint = SecurityCheckPlugin::$pluginInstance->getBuiltinFuncTaint( $trialFuncName ); |
| 459 | if ( $taint !== null ) { |
| 460 | $taint = clone $taint; |
| 461 | self::doSetFuncTaint( $func, $taint ); |
| 462 | if ( !$func->isPHPInternal() ) { |
| 463 | // Caused-by lines are presumably unnecessary for PHP internal stuff. |
| 464 | $this->maybeAddFuncError( $func, "Builtin-$trialFuncName", $taint, $taint ); |
| 465 | } |
| 466 | return $taint; |
| 467 | } |
| 468 | } |
| 469 | |
| 470 | $definingFunc = $this->getDefiningFuncIfDifferent( $func ); |
| 471 | if ( $definingFunc ) { |
| 472 | $definingFuncTaint = self::getFuncTaint( $definingFunc ); |
| 473 | if ( $definingFuncTaint !== null ) { |
| 474 | return $definingFuncTaint; |
| 475 | } |
| 476 | } |
| 477 | |
| 478 | return null; |
| 479 | } |
| 480 | |
| 481 | /** |
| 482 | * Analyze a function. This is very similar to Analyzable::analyze, but avoids several checks |
| 483 | * used by phan for performance. Phan doesn't know about taintedness, so it may decide to skip |
| 484 | * a re-analysis which we need. |
| 485 | * @todo This is a bit hacky. |
| 486 | * @todo We should implement our own perf checks, e.g. if the method as already called with |
| 487 | * the same taintedness, taint links, etc. for all params. |
| 488 | * @see \Phan\Analysis\Analyzable::analyze() |
| 489 | * |
| 490 | * @param FunctionInterface $func |
| 491 | */ |
| 492 | public function analyzeFunc( FunctionInterface $func ): void { |
| 493 | $node = $func->getNode(); |
| 494 | if ( !$node ) { |
| 495 | return; |
| 496 | } |
| 497 | |
| 498 | if ( $this->context->isInFunctionLikeScope() && $func->getFQSEN() === $this->context->getFunctionLikeFQSEN() ) { |
| 499 | // Avoid pointless recursion |
| 500 | return; |
| 501 | } |
| 502 | |
| 503 | static $depth = 0; |
| 504 | // @todo Tune the max depth. Raw benchmarking shows very little difference between e.g. |
| 505 | // 5 and 10. However, while with higher values we can detect more issues and avoid more |
| 506 | // false positives, it becomes harder to tell where an issue is coming from. |
| 507 | // Thus, this value should be increased only when we'll have better error reporting. |
| 508 | if ( $depth > 5 ) { |
| 509 | // $this->debug( __METHOD__, 'WARNING: aborting analysis earlier due to max depth' ); |
| 510 | return; |
| 511 | } |
| 512 | if ( $node->kind === \ast\AST_CLOSURE && isset( $node->children['uses'] ) ) { |
| 513 | return; |
| 514 | } |
| 515 | $depth++; |
| 516 | |
| 517 | // Like Analyzable::analyze, clone the context to avoid overriding anything |
| 518 | $context = clone $func->getContext(); |
| 519 | // @phan-suppress-next-line PhanUndeclaredMethod All implementations have it |
| 520 | if ( $func->getRecursionDepth() !== 0 ) { |
| 521 | // Add the arguments types to the internal scope of the function, see |
| 522 | // https://github.com/phan/phan/issues/3848 |
| 523 | foreach ( $func->getParameterList() as $parameter ) { |
| 524 | $context->addScopeVariable( $parameter->cloneAsNonVariadic() ); |
| 525 | } |
| 526 | } |
| 527 | try { |
| 528 | ( new BlockAnalysisVisitor( $this->code_base, $context ) )( |
| 529 | $node |
| 530 | ); |
| 531 | } finally { |
| 532 | $depth--; |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | /** |
| 537 | * Obtain taint information from a docblock comment. |
| 538 | * |
| 539 | * @param FunctionInterface $func The function to check |
| 540 | * @return array<FunctionTaintedness|MethodLinks>|null null for no info |
| 541 | * @phan-return array{0:FunctionTaintedness,1:MethodLinks}|null |
| 542 | */ |
| 543 | protected function getDocBlockTaintOfFunc( FunctionInterface $func ): ?array { |
| 544 | // Note that we're not using the hashed docblock for caching, because the same docblock |
| 545 | // may have different meanings in different contexts. E.g. @return self |
| 546 | $fqsen = (string)$func->getFQSEN(); |
| 547 | if ( isset( SecurityCheckPlugin::$docblockCache[ $fqsen ] ) ) { |
| 548 | [ $taint, $links ] = SecurityCheckPlugin::$docblockCache[ $fqsen ]; |
| 549 | return [ clone $taint, clone $links ]; |
| 550 | } |
| 551 | |
| 552 | $docBlock = $func->getDocComment(); |
| 553 | if ( $docBlock === null ) { |
| 554 | return null; |
| 555 | } |
| 556 | if ( strpos( $docBlock, '-taint' ) === false ) { |
| 557 | // Lightweight check for methods that certainly aren't annotated |
| 558 | return null; |
| 559 | } |
| 560 | $lines = explode( "\n", $docBlock ); |
| 561 | /** @param string[] $args */ |
| 562 | $invalidLineIssueEmitter = function ( string $msg, array $args ) use ( $func ): void { |
| 563 | SecurityCheckPlugin::emitIssue( |
| 564 | $this->code_base, |
| 565 | // Emit issues at the line of the signature |
| 566 | $func->getContext(), |
| 567 | 'SecurityCheckInvalidAnnotation', |
| 568 | $msg, |
| 569 | $args |
| 570 | ); |
| 571 | }; |
| 572 | // Note, not forCaller, as that doesn't see variadic parameters |
| 573 | $calleeParamList = $func->getParameterList(); |
| 574 | $validTaintEncountered = false; |
| 575 | // Assume that if some of the taint is specified, then |
| 576 | // the person would specify all the dangerous taints, so |
| 577 | // don't set the unknown flag if not taint annotation on |
| 578 | // @return. |
| 579 | $funcTaint = new FunctionTaintedness( Taintedness::newSafe() ); |
| 580 | // TODO $fakeMethodLinks here is a bit hacky... |
| 581 | $fakeMethodLinks = new MethodLinks(); |
| 582 | foreach ( $lines as $line ) { |
| 583 | $m = []; |
| 584 | $trimmedLine = ltrim( rtrim( $line ), "* \t/" ); |
| 585 | if ( strpos( $trimmedLine, '@param-taint' ) === 0 ) { |
| 586 | $matched = preg_match( SecurityCheckPlugin::PARAM_ANNOTATION_REGEX, $trimmedLine, $m ); |
| 587 | if ( !$matched ) { |
| 588 | $invalidLineIssueEmitter( "Cannot parse taint line '{COMMENT}'", [ $trimmedLine ] ); |
| 589 | continue; |
| 590 | } |
| 591 | |
| 592 | $paramNumber = null; |
| 593 | $isVariadic = null; |
| 594 | foreach ( $calleeParamList as $i => $param ) { |
| 595 | if ( $m['paramname'] === $param->getName() ) { |
| 596 | $paramNumber = $i; |
| 597 | $isVariadic = $param->isVariadic(); |
| 598 | break; |
| 599 | } |
| 600 | } |
| 601 | if ( $paramNumber === null ) { |
| 602 | $invalidLineIssueEmitter( |
| 603 | 'Annotated parameter ${PARAMETER} not found in the signature', |
| 604 | [ $m['paramname'] ] |
| 605 | ); |
| 606 | continue; |
| 607 | } |
| 608 | |
| 609 | $annotatedAsVariadic = $m['variadic'] !== ''; |
| 610 | if ( $isVariadic !== $annotatedAsVariadic ) { |
| 611 | $msg = $isVariadic |
| 612 | ? 'Variadic parameter ${PARAMETER} should be annotated as `...${PARAMETER}`' |
| 613 | : 'Non-variadic parameter ${PARAMETER} should be annotated as `${PARAMETER}`'; |
| 614 | $invalidLineIssueEmitter( $msg, [ $m['paramname'], $m['paramname'] ] ); |
| 615 | } |
| 616 | $taintData = SecurityCheckPlugin::parseTaintLine( $m['taint'] ); |
| 617 | if ( $taintData === null ) { |
| 618 | $invalidLineIssueEmitter( "Invalid param taintedness '{COMMENT}'", [ $m['taint'] ] ); |
| 619 | continue; |
| 620 | } |
| 621 | /** @var Taintedness $taint */ |
| 622 | [ $taint, $flags ] = $taintData; |
| 623 | $sinkTaint = $taint->withOnly( SecurityCheckPlugin::ALL_EXEC_TAINT ); |
| 624 | $preserveTaint = $taint->without( SecurityCheckPlugin::ALL_EXEC_TAINT )->asPreservedTaintedness(); |
| 625 | if ( $isVariadic ) { |
| 626 | $funcTaint->setVariadicParamSinkTaint( $paramNumber, $sinkTaint ); |
| 627 | $funcTaint->setVariadicParamPreservedTaint( $paramNumber, $preserveTaint ); |
| 628 | $funcTaint->addVariadicParamFlags( $flags ); |
| 629 | } else { |
| 630 | $funcTaint->setParamSinkTaint( $paramNumber, $sinkTaint ); |
| 631 | $funcTaint->setParamPreservedTaint( $paramNumber, $preserveTaint ); |
| 632 | $funcTaint->addParamFlags( $paramNumber, $flags ); |
| 633 | } |
| 634 | $fakeMethodLinks->initializeParamForFunc( $func, $paramNumber ); |
| 635 | $validTaintEncountered = true; |
| 636 | if ( ( $taint->get() & SecurityCheckPlugin::ESCAPES_HTML ) === SecurityCheckPlugin::ESCAPES_HTML ) { |
| 637 | // Special case to auto-set anything that escapes html to detect double escaping. |
| 638 | $funcTaint->setOverall( $funcTaint->getOverall()->with( SecurityCheckPlugin::ESCAPED_TAINT ) ); |
| 639 | } |
| 640 | } elseif ( strpos( $trimmedLine, '@return-taint' ) === 0 ) { |
| 641 | $taintLine = substr( $trimmedLine, strlen( '@return-taint' ) + 1 ); |
| 642 | $taintData = SecurityCheckPlugin::parseTaintLine( $taintLine ); |
| 643 | if ( $taintData === null ) { |
| 644 | $invalidLineIssueEmitter( "Invalid return taintedness '{COMMENT}'", [ $taintLine ] ); |
| 645 | continue; |
| 646 | } |
| 647 | /** @var Taintedness $taint */ |
| 648 | [ $taint, $flags ] = $taintData; |
| 649 | if ( $taint->has( SecurityCheckPlugin::ALL_EXEC_TAINT ) ) { |
| 650 | $invalidLineIssueEmitter( "Return taintedness cannot be exec", [] ); |
| 651 | continue; |
| 652 | } |
| 653 | $funcTaint->setOverall( $taint ); |
| 654 | $funcTaint->addOverallFlags( $flags ); |
| 655 | $validTaintEncountered = true; |
| 656 | } |
| 657 | } |
| 658 | |
| 659 | if ( !$validTaintEncountered ) { |
| 660 | $this->debug( __METHOD__, 'Possibly wrong taint annotation in docblock: ' . json_encode( $docBlock ) ); |
| 661 | } |
| 662 | |
| 663 | SecurityCheckPlugin::$docblockCache[ $fqsen ] = $validTaintEncountered |
| 664 | ? [ clone $funcTaint, clone $fakeMethodLinks ] |
| 665 | : null; |
| 666 | return SecurityCheckPlugin::$docblockCache[ $fqsen ]; |
| 667 | } |
| 668 | |
| 669 | /** |
| 670 | * Given a type, determine what type of taint |
| 671 | * |
| 672 | * e.g. Integers are probably untainted since its hard to do evil |
| 673 | * with them, but mark strings as unknown since we don't know. |
| 674 | * |
| 675 | * Only use as a fallback |
| 676 | * @param UnionType $types The types |
| 677 | * @return Taintedness |
| 678 | */ |
| 679 | protected function getTaintByType( UnionType $types ): Taintedness { |
| 680 | // NOTE: This flattens intersection types |
| 681 | $typelist = $types->getUniqueFlattenedTypeSet(); |
| 682 | if ( !$typelist ) { |
| 683 | // $this->debug( __METHOD__, "Setting type unknown due to no type info." ); |
| 684 | return new Taintedness( SecurityCheckPlugin::UNKNOWN_TAINT ); |
| 685 | } |
| 686 | |
| 687 | $taint = new Taintedness( SecurityCheckPlugin::NO_TAINT ); |
| 688 | $isPossiblyUnknown = false; |
| 689 | foreach ( $typelist as $type ) { |
| 690 | if ( $type instanceof LiteralTypeInterface ) { |
| 691 | // We're going to assume that literals aren't tainted... |
| 692 | continue; |
| 693 | } |
| 694 | switch ( $type->getName() ) { |
| 695 | case 'int': |
| 696 | case 'non-zero-int': |
| 697 | case 'float': |
| 698 | case 'bool': |
| 699 | case 'false': |
| 700 | case 'true': |
| 701 | case 'null': |
| 702 | case 'void': |
| 703 | case 'class-string': |
| 704 | case 'callable-string': |
| 705 | case 'callable-object': |
| 706 | case 'callable-array': |
| 707 | break; |
| 708 | case 'string': |
| 709 | case 'non-empty-string': |
| 710 | case 'Closure': |
| 711 | case 'callable': |
| 712 | case 'array': |
| 713 | case 'iterable': |
| 714 | case 'object': |
| 715 | case 'resource': |
| 716 | case 'mixed': |
| 717 | case 'non-empty-mixed': |
| 718 | case 'non-null-mixed': |
| 719 | // $this->debug( __METHOD__, "Taint set unknown due to type '$type'." ); |
| 720 | $isPossiblyUnknown = true; |
| 721 | break; |
| 722 | default: |
| 723 | if ( $type->hasTemplateTypeRecursive() ) { |
| 724 | // TODO Can we do better for template types? |
| 725 | $isPossiblyUnknown = true; |
| 726 | break; |
| 727 | } |
| 728 | |
| 729 | if ( !$type->isObjectWithKnownFQSEN() ) { |
| 730 | // Likely some phan-specific types not included above |
| 731 | $this->debug( __METHOD__, " $type (" . get_class( $type ) . ') not a class?' ); |
| 732 | $isPossiblyUnknown = true; |
| 733 | break; |
| 734 | } |
| 735 | |
| 736 | $fqsenStr = $type->asFQSEN()->__toString(); |
| 737 | if ( isset( self::$fqsensWithoutToStringCache[$fqsenStr] ) ) { |
| 738 | $isPossiblyUnknown = true; |
| 739 | break; |
| 740 | } |
| 741 | |
| 742 | // This means specific class, so look up __toString() |
| 743 | $toStringFQSEN = FullyQualifiedMethodName::fromStringInContext( |
| 744 | $fqsenStr . '::__toString', |
| 745 | $this->context |
| 746 | ); |
| 747 | if ( !$this->code_base->hasMethodWithFQSEN( $toStringFQSEN ) ) { |
| 748 | // This is common in a void context. |
| 749 | // e.g. code like $this->foo() will reach this |
| 750 | // check. |
| 751 | self::$fqsensWithoutToStringCache[$fqsenStr] = true; |
| 752 | $isPossiblyUnknown = true; |
| 753 | break; |
| 754 | } |
| 755 | $toString = $this->code_base->getMethodByFQSEN( $toStringFQSEN ); |
| 756 | $toStringTaint = $this->getTaintOfFunction( $toString ); |
| 757 | $taint->mergeWith( $toStringTaint->getOverall()->without( |
| 758 | SecurityCheckPlugin::PRESERVE_TAINT | SecurityCheckPlugin::ALL_EXEC_TAINT |
| 759 | ) ); |
| 760 | } |
| 761 | } |
| 762 | if ( $isPossiblyUnknown ) { |
| 763 | $taint->add( SecurityCheckPlugin::UNKNOWN_TAINT ); |
| 764 | } |
| 765 | return $taint; |
| 766 | } |
| 767 | |
| 768 | /** |
| 769 | * Get what taint types are allowed on a typed element (i.e. use its type to rule out |
| 770 | * impossible taint types). |
| 771 | * |
| 772 | * @param TypedElementInterface $var |
| 773 | * @return Taintedness|null Null means all taints, checking for null is faster than ORing |
| 774 | */ |
| 775 | protected function getTaintMaskForTypedElement( TypedElementInterface $var ): ?Taintedness { |
| 776 | if ( $var instanceof GlobalVariable ) { |
| 777 | // TODO We wouldn't need to do this if phan didn't infer real types for global variables. |
| 778 | // See https://github.com/phan/phan/issues/4518 |
| 779 | $var = $var->getElement(); |
| 780 | } |
| 781 | // Note, we must use the real union type because: |
| 782 | // 1 - The non-real type might be wrong |
| 783 | // 2 - The non-real type might be incomplete (e.g. when analysing a func without docblock |
| 784 | // we still don't know all the possible types of the params). |
| 785 | return $this->getTaintMaskForType( $var->getUnionType()->getRealUnionType() ); |
| 786 | } |
| 787 | |
| 788 | /** |
| 789 | * Get what taint types are allowed on an element with the given type. |
| 790 | * |
| 791 | * @param UnionType $type |
| 792 | * @return Taintedness|null Null for all flags |
| 793 | */ |
| 794 | protected function getTaintMaskForType( UnionType $type ): ?Taintedness { |
| 795 | $typeTaint = $this->getTaintByType( $type ); |
| 796 | |
| 797 | if ( $typeTaint->has( SecurityCheckPlugin::UNKNOWN_TAINT ) ) { |
| 798 | return null; |
| 799 | } |
| 800 | return $typeTaint; |
| 801 | } |
| 802 | |
| 803 | /** |
| 804 | * Get what taint the element could have in the future. For instance, a func parameter may initially |
| 805 | * have no taint, but it may become tainted depending on the argument. |
| 806 | * @todo Ensure this won't miss any case (aside from when phan infers a wrong real type) |
| 807 | * |
| 808 | * @param TypedElementInterface $el |
| 809 | * @return Taintedness|null Null for all taints |
| 810 | */ |
| 811 | protected function getPossibleFutureTaintOfElement( TypedElementInterface $el ): ?Taintedness { |
| 812 | return $this->getTaintMaskForTypedElement( $el ); |
| 813 | } |
| 814 | |
| 815 | /** |
| 816 | * Get name of current method (for debugging purposes) |
| 817 | * |
| 818 | * @return string Name of method or "[no method]" |
| 819 | */ |
| 820 | protected function getCurrentMethod(): string { |
| 821 | return $this->context->isInFunctionLikeScope() ? |
| 822 | (string)$this->context->getFunctionLikeFQSEN() : '[no method]'; |
| 823 | } |
| 824 | |
| 825 | /** |
| 826 | * Get the taintedness of something from the AST tree. |
| 827 | * |
| 828 | * @param mixed $expr An expression from the AST tree. |
| 829 | * @return TaintednessWithError |
| 830 | */ |
| 831 | protected function getTaintedness( $expr ): TaintednessWithError { |
| 832 | if ( $expr instanceof Node ) { |
| 833 | return $this->getTaintednessNode( $expr ); |
| 834 | } |
| 835 | |
| 836 | assert( is_scalar( $expr ) || $expr === null ); |
| 837 | // Optim: avoid using TaintednessWithError::newEmpty() |
| 838 | return new TaintednessWithError( |
| 839 | new Taintedness( SecurityCheckPlugin::NO_TAINT ), |
| 840 | new CausedByLines(), |
| 841 | new MethodLinks() |
| 842 | ); |
| 843 | } |
| 844 | |
| 845 | /** |
| 846 | * Give an AST node, find its taint. This always returns a copy. |
| 847 | * |
| 848 | * @param Node $node |
| 849 | * @return TaintednessWithError |
| 850 | * @suppress PhanUndeclaredProperty |
| 851 | */ |
| 852 | protected function getTaintednessNode( Node $node ): TaintednessWithError { |
| 853 | // Performance: use isset(), not property_exists() |
| 854 | if ( isset( $node->taint ) ) { |
| 855 | // Return cached result. Cache hit ratio should ideally be 100%, because we should never have to retrieve |
| 856 | // the taintedness of a node without having analyzed it first. For now the ratio is lower because |
| 857 | // we don't cache the result of cheap nodes. |
| 858 | return $node->taint; |
| 859 | } |
| 860 | // TODO This might just a return a default if no cached data. |
| 861 | |
| 862 | // Debug::printNode( $node ); |
| 863 | // Make sure to update the line number, or the same issue may be reported |
| 864 | // more than once on different lines (see test 'multilineissue'). |
| 865 | $oldLine = $this->context->getLineNumberStart(); |
| 866 | $this->context->setLineNumberStart( $node->lineno ); |
| 867 | |
| 868 | $visitor = new TaintednessVisitor( $this->code_base, $this->context ); |
| 869 | try { |
| 870 | return $visitor->analyzeNodeAndGetTaintedness( $node ); |
| 871 | } finally { |
| 872 | $this->context->setLineNumberStart( $oldLine ); |
| 873 | } |
| 874 | } |
| 875 | |
| 876 | /** |
| 877 | * Given a phan object (not method/function) find its taint. This always returns a copy |
| 878 | * for existing objects. |
| 879 | * |
| 880 | * @param TypedElementInterface $variableObj |
| 881 | * @return Taintedness |
| 882 | */ |
| 883 | protected function getTaintednessPhanObj( TypedElementInterface $variableObj ): Taintedness { |
| 884 | assert( !$variableObj instanceof FunctionInterface, "This method cannot be used with methods" ); |
| 885 | $taintOrNull = self::getTaintednessRaw( $variableObj ); |
| 886 | if ( $taintOrNull !== null ) { |
| 887 | $mask = $this->getTaintMaskForTypedElement( $variableObj ); |
| 888 | $taintedness = $mask !== null ? $taintOrNull->withOnly( $mask->get() ) : clone $taintOrNull; |
| 889 | // echo "$varName has taintedness $taintedness due to last time\n"; |
| 890 | } else { |
| 891 | $type = $variableObj->getUnionType(); |
| 892 | $taintedness = $this->getTaintByType( $type ); |
| 893 | // $this->debug( " \$" . $variableObj->getName() . " first sight." |
| 894 | // . " taintedness set to $taintedness due to type $type\n"; |
| 895 | } |
| 896 | return $taintedness; |
| 897 | } |
| 898 | |
| 899 | /** |
| 900 | * Shortcut to resolve array offsets, which includes: |
| 901 | * - Ensuring that the value is not null: null is used for implicit dims like in `$a[] = $b`; we can't say |
| 902 | * for sure what the offset will be, and this method would return null (interpreted as offset 0), which is |
| 903 | * most likely wrong. |
| 904 | * - Casting floats to integers, since using a float as array key raises a warning (and crashes taint-check) |
| 905 | * in PHP 8.1 (T307504) |
| 906 | * - Letting nodes that represent resources (e.g. `STDIN`) pass through, since they're not scalar and certainly |
| 907 | * not valid offsets (see https://github.com/phan/phan/issues/4659). |
| 908 | * |
| 909 | * @param Node|mixed $rawOffset |
| 910 | * @return Node|mixed |
| 911 | */ |
| 912 | protected function resolveOffset( $rawOffset ) { |
| 913 | assert( $rawOffset !== null ); |
| 914 | $resolved = $this->resolveValue( $rawOffset ); |
| 915 | // phpcs:ignore MediaWiki.Usage.ForbiddenFunctions.is_resource |
| 916 | if ( is_resource( $resolved ) ) { |
| 917 | return $rawOffset; |
| 918 | } |
| 919 | return is_float( $resolved ) ? (int)$resolved : $resolved; |
| 920 | } |
| 921 | |
| 922 | /** |
| 923 | * Shortcut to try and turn an AST element (Node or already literal) into an equivalent PHP |
| 924 | * scalar value. |
| 925 | * |
| 926 | * @param Node|mixed $value A Node or a scalar value from the AST |
| 927 | * @return Node|mixed An equivalent scalar PHP value, or $value if it cannot be resolved |
| 928 | */ |
| 929 | protected function resolveValue( $value ) { |
| 930 | if ( !$value instanceof Node ) { |
| 931 | return $value; |
| 932 | } |
| 933 | return $this->getCtxN( $value )->getEquivalentPHPScalarValue(); |
| 934 | } |
| 935 | |
| 936 | /** |
| 937 | * Get a property by name in the current scope, failing hard if it cannot be found. |
| 938 | * @param string $propName |
| 939 | * @return Property |
| 940 | */ |
| 941 | private function getPropInCurrentScopeByName( string $propName ): Property { |
| 942 | assert( $this->context->isInClassScope() ); |
| 943 | $clazz = $this->context->getClassInScope( $this->code_base ); |
| 944 | |
| 945 | assert( $clazz->hasPropertyWithName( $this->code_base, $propName ) ); |
| 946 | return $clazz->getPropertyByName( $this->code_base, $propName ); |
| 947 | } |
| 948 | |
| 949 | /** |
| 950 | * Quick wrapper to get the ContextNode for a node |
| 951 | * |
| 952 | * @param Node|mixed $node |
| 953 | * @return ContextNode |
| 954 | */ |
| 955 | protected function getCtxN( $node ): ContextNode { |
| 956 | return new ContextNode( |
| 957 | $this->code_base, |
| 958 | $this->context, |
| 959 | $node |
| 960 | ); |
| 961 | } |
| 962 | |
| 963 | /** |
| 964 | * Given a node, return the Phan variable objects that |
| 965 | * correspond to that node to which we can backpropagate a NUMKEY taintedness. |
| 966 | * |
| 967 | * @todo This should be handled together with the non-numkey case |
| 968 | * |
| 969 | * @param Node $node AST node in question |
| 970 | * @return TypedElementInterface[] Array of various phan objects corresponding to $node |
| 971 | */ |
| 972 | protected function getObjsForNodeForNumkeyBackprop( Node $node ): array { |
| 973 | $cn = $this->getCtxN( $node ); |
| 974 | |
| 975 | // TODO For now we only backprop in the simple case, to avoid tons of false positives, unless |
| 976 | // the env flag is set (chiefly for tests) |
| 977 | $definitelyNumkey = !getenv( 'SECCHECK_NUMKEY_SPERIMENTAL' ); |
| 978 | |
| 979 | switch ( $node->kind ) { |
| 980 | case \ast\AST_PROP: |
| 981 | case \ast\AST_NULLSAFE_PROP: |
| 982 | case \ast\AST_STATIC_PROP: |
| 983 | $prop = $this->getPropFromNode( $node ); |
| 984 | return $prop && $this->elementCanBeNumkey( $prop, $definitelyNumkey ) ? [ $prop ] : []; |
| 985 | case \ast\AST_VAR: |
| 986 | case \ast\AST_CLOSURE_VAR: |
| 987 | if ( Variable::isHardcodedGlobalVariableWithName( $cn->getVariableName() ) ) { |
| 988 | return []; |
| 989 | } |
| 990 | try { |
| 991 | $var = $cn->getVariable(); |
| 992 | return $this->elementCanBeNumkey( $var, $definitelyNumkey ) ? [ $var ] : []; |
| 993 | } catch ( NodeException | IssueException $e ) { |
| 994 | $this->debug( __METHOD__, "variable not in scope?? " . $this->getDebugInfo( $e ) ); |
| 995 | return []; |
| 996 | } |
| 997 | case \ast\AST_ENCAPS_LIST: |
| 998 | case \ast\AST_ARRAY: |
| 999 | $results = []; |
| 1000 | foreach ( $node->children as $child ) { |
| 1001 | if ( !$child instanceof Node ) { |
| 1002 | continue; |
| 1003 | } |
| 1004 | |
| 1005 | if ( |
| 1006 | $node->kind === \ast\AST_ARRAY && |
| 1007 | $child->children['key'] !== null && !$this->nodeCanBeIntKey( $child->children['key'] ) |
| 1008 | ) { |
| 1009 | continue; |
| 1010 | } |
| 1011 | $results = array_merge( $this->getObjsForNodeForNumkeyBackprop( $child ), $results ); |
| 1012 | } |
| 1013 | return $results; |
| 1014 | case \ast\AST_ARRAY_ELEM: |
| 1015 | $results = []; |
| 1016 | if ( $node->children['key'] instanceof Node ) { |
| 1017 | $results = array_merge( |
| 1018 | $this->getObjsForNodeForNumkeyBackprop( $node->children['key'] ), |
| 1019 | $results |
| 1020 | ); |
| 1021 | } |
| 1022 | if ( $node->children['value'] instanceof Node ) { |
| 1023 | $results = array_merge( |
| 1024 | $this->getObjsForNodeForNumkeyBackprop( $node->children['value'] ), |
| 1025 | $results |
| 1026 | ); |
| 1027 | } |
| 1028 | return $results; |
| 1029 | case \ast\AST_CAST: |
| 1030 | // Future todo might be to ignore casts to ints, since |
| 1031 | // such things should be safe. Unclear if that makes |
| 1032 | // sense in all circumstances. |
| 1033 | if ( $node->children['expr'] instanceof Node ) { |
| 1034 | return $this->getObjsForNodeForNumkeyBackprop( $node->children['expr'] ); |
| 1035 | } |
| 1036 | return []; |
| 1037 | case \ast\AST_DIM: |
| 1038 | if ( $node->children['expr'] instanceof Node ) { |
| 1039 | // For now just consider the outermost array. |
| 1040 | // FIXME. doesn't handle tainted array keys! |
| 1041 | return $this->getObjsForNodeForNumkeyBackprop( $node->children['expr'] ); |
| 1042 | } |
| 1043 | return []; |
| 1044 | case \ast\AST_UNARY_OP: |
| 1045 | $var = $node->children['expr']; |
| 1046 | return $var instanceof Node ? $this->getObjsForNodeForNumkeyBackprop( $var ) : []; |
| 1047 | case \ast\AST_BINARY_OP: |
| 1048 | $left = $node->children['left']; |
| 1049 | $right = $node->children['right']; |
| 1050 | $leftObj = $left instanceof Node ? $this->getObjsForNodeForNumkeyBackprop( $left ) : []; |
| 1051 | $rightObj = $right instanceof Node ? $this->getObjsForNodeForNumkeyBackprop( $right ) : []; |
| 1052 | return array_merge( $leftObj, $rightObj ); |
| 1053 | case \ast\AST_CONDITIONAL: |
| 1054 | $t = $node->children['true']; |
| 1055 | $f = $node->children['false']; |
| 1056 | $tObj = $t instanceof Node ? $this->getObjsForNodeForNumkeyBackprop( $t ) : []; |
| 1057 | $fObj = $f instanceof Node ? $this->getObjsForNodeForNumkeyBackprop( $f ) : []; |
| 1058 | return array_merge( $tObj, $fObj ); |
| 1059 | case \ast\AST_CONST: |
| 1060 | case \ast\AST_CLASS_CONST: |
| 1061 | case \ast\AST_CLASS_NAME: |
| 1062 | case \ast\AST_MAGIC_CONST: |
| 1063 | case \ast\AST_ISSET: |
| 1064 | case \ast\AST_NEW: |
| 1065 | // For now we don't do methods, only variables |
| 1066 | // Also don't do args to function calls. |
| 1067 | // Unclear if this makes sense. |
| 1068 | return []; |
| 1069 | case \ast\AST_CALL: |
| 1070 | case \ast\AST_STATIC_CALL: |
| 1071 | case \ast\AST_METHOD_CALL: |
| 1072 | case \ast\AST_NULLSAFE_METHOD_CALL: |
| 1073 | if ( $definitelyNumkey ) { |
| 1074 | // This case is too hard for now. |
| 1075 | return []; |
| 1076 | } |
| 1077 | $ctxNode = $this->getCtxN( $node ); |
| 1078 | // @todo Future todo might be to still return arguments when catching an exception. |
| 1079 | if ( $node->kind === \ast\AST_CALL ) { |
| 1080 | if ( $node->children['expr']->kind !== \ast\AST_NAME ) { |
| 1081 | // TODO Handle this case! |
| 1082 | return []; |
| 1083 | } |
| 1084 | try { |
| 1085 | $func = $ctxNode->getFunction( $node->children['expr']->children['name'] ); |
| 1086 | } catch ( IssueException | FQSENException $e ) { |
| 1087 | $this->debug( __METHOD__, "FIXME func not found: " . $this->getDebugInfo( $e ) ); |
| 1088 | return []; |
| 1089 | } |
| 1090 | } else { |
| 1091 | $methodName = $node->children['method']; |
| 1092 | try { |
| 1093 | $func = $ctxNode->getMethod( $methodName, $node->kind === \ast\AST_STATIC_CALL, true ); |
| 1094 | } catch ( NodeException | CodeBaseException | IssueException $e ) { |
| 1095 | $this->debug( __METHOD__, "FIXME method not found: " . $this->getDebugInfo( $e ) ); |
| 1096 | return []; |
| 1097 | } |
| 1098 | } |
| 1099 | try { |
| 1100 | return $this->getReturnObjsOfFunc( $func ); |
| 1101 | } catch ( Exception $e ) { |
| 1102 | $this->debug( __METHOD__, "FIXME: " . $this->getDebugInfo( $e ) ); |
| 1103 | return []; |
| 1104 | } |
| 1105 | case \ast\AST_PRE_INC: |
| 1106 | case \ast\AST_PRE_DEC: |
| 1107 | case \ast\AST_POST_INC: |
| 1108 | case \ast\AST_POST_DEC: |
| 1109 | $children = $node->children; |
| 1110 | assert( count( $children ) === 1 ); |
| 1111 | return $this->getObjsForNodeForNumkeyBackprop( reset( $children ) ); |
| 1112 | default: |
| 1113 | // TODO Should probably handle AST_MATCH & friends |
| 1114 | // Debug::printNode( $node ); |
| 1115 | // This should really be a visitor that recurses into |
| 1116 | // things. |
| 1117 | $this->debug( __METHOD__, "FIXME unhandled case" |
| 1118 | . Debug::nodeName( $node ) . "\n" |
| 1119 | ); |
| 1120 | return []; |
| 1121 | } |
| 1122 | } |
| 1123 | |
| 1124 | /** |
| 1125 | * @param Node $node |
| 1126 | * @return Property|null |
| 1127 | */ |
| 1128 | protected function getPropFromNode( Node $node ): ?Property { |
| 1129 | try { |
| 1130 | return $this->getCtxN( $node )->getProperty( $node->kind === \ast\AST_STATIC_PROP ); |
| 1131 | } catch ( NodeException | IssueException | UnanalyzableException $e ) { |
| 1132 | $this->debug( __METHOD__, "Cannot determine " . |
| 1133 | "property (Maybe don't know what class) - " . |
| 1134 | $this->getDebugInfo( $e ) |
| 1135 | ); |
| 1136 | return null; |
| 1137 | } |
| 1138 | } |
| 1139 | |
| 1140 | /** |
| 1141 | * Extract some useful debug data from an exception |
| 1142 | * @param Exception $e |
| 1143 | * @return string |
| 1144 | */ |
| 1145 | protected function getDebugInfo( Exception $e ): string { |
| 1146 | return $e instanceof IssueException |
| 1147 | ? $e->getIssueInstance()->__toString() |
| 1148 | : ( get_class( $e ) . " {$e->getMessage()}" ); |
| 1149 | } |
| 1150 | |
| 1151 | /** |
| 1152 | * Get the current filename and line. |
| 1153 | * |
| 1154 | * @param Context|null $context Override the context to make debug info for |
| 1155 | * @return string path/to/file +linenumber |
| 1156 | */ |
| 1157 | protected function dbgInfo( Context $context = null ): string { |
| 1158 | $ctx = $context ?: $this->context; |
| 1159 | // Using a + instead of : so that I can just copy and paste |
| 1160 | // into a vim command line. |
| 1161 | return $ctx->getFile() . ' +' . $ctx->getLineNumberStart(); |
| 1162 | } |
| 1163 | |
| 1164 | /** |
| 1165 | * Link together a Method and its parameters,the idea being if the method gets called with something evil |
| 1166 | * later, we can traceback anything it might affect. |
| 1167 | * Note that we don't do this for functions with hardcoded taint, in which case we assume that any dangerous |
| 1168 | * association was already hardcoded. This is also good for performance, because hardcoded function tend to be |
| 1169 | * used a lot (for MW, think of methods in Database or in Html). |
| 1170 | * |
| 1171 | * @param Variable $param The variable object for the parameter. This can also be |
| 1172 | * instance of Parameter (subclass of Variable). |
| 1173 | * @param FunctionInterface $func The function/method in question |
| 1174 | * @param int $i Which argument number is $param |
| 1175 | */ |
| 1176 | protected function linkParamAndFunc( Variable $param, FunctionInterface $func, int $i ): void { |
| 1177 | // $this->debug( __METHOD__, "Linking '$param' to '$func' arg $i" ); |
| 1178 | |
| 1179 | // TODO Use $func's builtin/annotated taintedness (available in PreTaintednessVisitor) to check this per |
| 1180 | // parameter (looking at NO_OVERRIDE) |
| 1181 | $canLinkParam = !SecurityCheckPlugin::$pluginInstance->builtinFuncHasTaint( $func->getFQSEN() ); |
| 1182 | if ( !$canLinkParam ) { |
| 1183 | return; |
| 1184 | } |
| 1185 | |
| 1186 | self::ensureVarLinksForArgExist( $func, $i ); |
| 1187 | |
| 1188 | $paramLinks = self::getMethodLinksCloneOrEmpty( $param ); |
| 1189 | $paramLinks->initializeParamForFunc( $func, $i ); |
| 1190 | self::setMethodLinks( $param, $paramLinks ); |
| 1191 | } |
| 1192 | |
| 1193 | /** |
| 1194 | * Given a LHS and RHS make all the methods that can set RHS also for LHS |
| 1195 | * |
| 1196 | * Given 2 variables (e.g. $lhs = $rhs ), see to it that any function/method |
| 1197 | * which we marked as being able to set the value of rhs, is also marked |
| 1198 | * as being able to set the value of lhs. We use this information to figure |
| 1199 | * out what method parameter is causing the return statement to be tainted. |
| 1200 | * |
| 1201 | * @warning Be careful calling this function if lhs already has taint |
| 1202 | * or rhs side is a compound statement. This could result in misattribution |
| 1203 | * of where the taint is coming from. |
| 1204 | * |
| 1205 | * This also merges the information on what line caused the taint. |
| 1206 | * |
| 1207 | * @param TypedElementInterface $lhs Source of method list |
| 1208 | * @param MethodLinks $rhsLinks New links |
| 1209 | * @param bool $override |
| 1210 | */ |
| 1211 | protected function mergeTaintDependencies( |
| 1212 | TypedElementInterface $lhs, |
| 1213 | MethodLinks $rhsLinks, |
| 1214 | bool $override |
| 1215 | ): void { |
| 1216 | // So if we have $a = $b; |
| 1217 | // First we find out all the methods that can set $b |
| 1218 | // Then we add $a to the list of variables that those methods can set. |
| 1219 | // Last we add these methods to $a's list of all methods that can set it. |
| 1220 | |
| 1221 | $curLinks = self::getMethodLinks( $lhs ); |
| 1222 | if ( $override || !$curLinks ) { |
| 1223 | $newLinks = $rhsLinks; |
| 1224 | } else { |
| 1225 | $newLinks = $curLinks->asMergedWith( $rhsLinks ); |
| 1226 | } |
| 1227 | |
| 1228 | if ( $lhs instanceof Property || $lhs instanceof GlobalVariable || $lhs instanceof PassByReferenceVariable ) { |
| 1229 | // Don't attach things like Variable and Parameter. These are local elements, and setting taint |
| 1230 | // on them in markAllDependentVarsYes would have no effect. Additionally, since phan creates a new |
| 1231 | // Parameter object for each analysis, we will end up with duplicated links that do nothing but |
| 1232 | // eating memory. |
| 1233 | foreach ( $newLinks->getMethodAndParamTuples() as [ $method, $index ] ) { |
| 1234 | $varLinks = self::getVarLinks( $method, $index ); |
| 1235 | assert( $varLinks instanceof VarLinksSet ); |
| 1236 | // $this->debug( __METHOD__, "During assignment, we link $lhs to $method($index)" ); |
| 1237 | $varLinks->attach( $lhs, $newLinks->asPreservedTaintednessForFuncParam( $method, $index ) ); |
| 1238 | } |
| 1239 | } |
| 1240 | |
| 1241 | self::setMethodLinks( $lhs, $newLinks ); |
| 1242 | } |
| 1243 | |
| 1244 | /** |
| 1245 | * Mark any function setting a specific variable as EXEC taint |
| 1246 | * |
| 1247 | * If you do something like echo $this->foo; |
| 1248 | * This method is called to make all things that set $this->foo |
| 1249 | * as TAINT_EXEC. |
| 1250 | * |
| 1251 | * @note This might have annoying false positives with widely used properties |
| 1252 | * that are used with different levels of escaping, which is not a good idea anyway. |
| 1253 | * |
| 1254 | * @param TypedElementInterface $var The variable in question |
| 1255 | * @param Taintedness $taint What taint to mark them as. |
| 1256 | * @param CausedByLines|null $additionalError Any extra caused-by lines to add |
| 1257 | */ |
| 1258 | protected function markAllDependentMethodsExec( |
| 1259 | TypedElementInterface $var, |
| 1260 | Taintedness $taint, |
| 1261 | CausedByLines $additionalError = null |
| 1262 | ): void { |
| 1263 | $futureTaint = $this->getPossibleFutureTaintOfElement( $var ); |
| 1264 | if ( $futureTaint !== null && !$futureTaint->has( $taint->get() ) ) { |
| 1265 | return; |
| 1266 | } |
| 1267 | // Ensure we only set exec bits, not normal taint bits. |
| 1268 | $taint = $taint->withOnly( SecurityCheckPlugin::BACKPROP_TAINTS ); |
| 1269 | if ( $taint->isSafe() || $this->isIssueSuppressedOrFalsePositive( $taint ) ) { |
| 1270 | return; |
| 1271 | } |
| 1272 | |
| 1273 | $varLinks = self::getMethodLinks( $var ); |
| 1274 | if ( $varLinks === null || $varLinks->isEmpty() ) { |
| 1275 | return; |
| 1276 | } |
| 1277 | $backpropError = self::getCausedByRawCloneOrEmpty( $var ); |
| 1278 | if ( $additionalError ) { |
| 1279 | $backpropError->mergeWith( $additionalError ); |
| 1280 | } |
| 1281 | |
| 1282 | // $this->debug( __METHOD__, "Setting {$var->getName()} exec {$taint->toShortString()}" ); |
| 1283 | $oldMem = memory_get_peak_usage(); |
| 1284 | foreach ( $taint->decomposeForLinks( $varLinks ) as [ $curLinks, $curTaint ] ) { |
| 1285 | /** @var LinksSet $curLinks */ |
| 1286 | /** @var Taintedness $curTaint */ |
| 1287 | foreach ( $curLinks as $method ) { |
| 1288 | $paramInfo = $curLinks[$method]; |
| 1289 | // Note, not forCaller, as that doesn't see variadic parameters |
| 1290 | $calleeParamList = $method->getParameterList(); |
| 1291 | $paramTaint = new FunctionTaintedness( Taintedness::newSafe() ); |
| 1292 | $funcError = new FunctionCausedByLines(); |
| 1293 | foreach ( $paramInfo->getParams() as $i => $paramOffsets ) { |
| 1294 | $curParTaint = $curTaint->asMovedAtRelevantOffsetsForBackprop( $paramOffsets ); |
| 1295 | $curBackpropError = $backpropError |
| 1296 | ->withTaintAddedToMethodArgLinks( $curParTaint->asExecToYesTaint(), $method, $i ); |
| 1297 | if ( isset( $calleeParamList[$i] ) && $calleeParamList[$i]->isVariadic() ) { |
| 1298 | $paramTaint->setVariadicParamSinkTaint( $i, $curParTaint ); |
| 1299 | $funcError->setVariadicParamSinkLines( $i, $curBackpropError ); |
| 1300 | } else { |
| 1301 | $paramTaint->setParamSinkTaint( $i, $curParTaint ); |
| 1302 | $funcError->setParamSinkLines( $i, $curBackpropError ); |
| 1303 | } |
| 1304 | // $this->debug( __METHOD__, "Setting method $method arg $i as $taint due to dependency on $var" ); |
| 1305 | } |
| 1306 | $this->addFuncTaint( $method, $paramTaint ); |
| 1307 | $newFuncTaint = self::getFuncTaint( $method ); |
| 1308 | assert( $newFuncTaint !== null ); |
| 1309 | $this->maybeAddFuncError( $method, null, $paramTaint, $newFuncTaint ); |
| 1310 | $this->mergeFuncError( $method, $funcError, $newFuncTaint ); |
| 1311 | } |
| 1312 | } |
| 1313 | |
| 1314 | $newMem = memory_get_peak_usage(); |
| 1315 | $diffMem = round( ( $newMem - $oldMem ) / ( 1024 * 1024 ) ); |
| 1316 | if ( $diffMem > 2 ) { |
| 1317 | $this->debug( __METHOD__, "Memory spike $diffMem for variable " . $var->getName() ); |
| 1318 | } |
| 1319 | } |
| 1320 | |
| 1321 | /** |
| 1322 | * Mark any function setting a specific variable as EXEC taint |
| 1323 | * |
| 1324 | * If you do something like echo $this->foo; |
| 1325 | * This method is called to make all things that set $this->foo |
| 1326 | * as TAINT_EXEC. |
| 1327 | * |
| 1328 | * @note This might have annoying false positives with widely used properties |
| 1329 | * that are used with different levels of escaping, which is not a good idea anyway. |
| 1330 | * |
| 1331 | * @param Node $node |
| 1332 | * @param Taintedness $taint What taint to mark them as. |
| 1333 | * @param CausedByLines|null $additionalError Additional caused-by lines to propagate |
| 1334 | * @param bool $tempNumkey Temporary param |
| 1335 | */ |
| 1336 | protected function markAllDependentMethodsExecForNode( |
| 1337 | Node $node, |
| 1338 | Taintedness $taint, |
| 1339 | CausedByLines $additionalError = null, |
| 1340 | bool $tempNumkey = false |
| 1341 | ): void { |
| 1342 | if ( !$tempNumkey ) { |
| 1343 | $backpropVisitor = new TaintednessBackpropVisitor( |
| 1344 | $this->code_base, |
| 1345 | $this->context, |
| 1346 | $taint, |
| 1347 | $additionalError |
| 1348 | ); |
| 1349 | $backpropVisitor( $node ); |
| 1350 | return; |
| 1351 | } |
| 1352 | $phanObjs = $this->getObjsForNodeForNumkeyBackprop( $node ); |
| 1353 | foreach ( array_unique( $phanObjs ) as $phanObj ) { |
| 1354 | $this->markAllDependentMethodsExec( $phanObj, $taint, $additionalError ); |
| 1355 | } |
| 1356 | } |
| 1357 | |
| 1358 | /** |
| 1359 | * This happens when someone calls foo( $evilTaintedVar ); |
| 1360 | * |
| 1361 | * It makes sure that any variable that the function foo() sets takes on |
| 1362 | * the taint of the supplied argument. |
| 1363 | * |
| 1364 | * @param FunctionInterface $method The function or method in question |
| 1365 | * @param int $i The number of the argument in question. |
| 1366 | * @param Taintedness $taint The taint to apply. |
| 1367 | * @param CausedByLines $error Caused-by lines to propagate |
| 1368 | */ |
| 1369 | protected function markAllDependentVarsYes( |
| 1370 | FunctionInterface $method, |
| 1371 | int $i, |
| 1372 | Taintedness $taint, |
| 1373 | CausedByLines $error |
| 1374 | ): void { |
| 1375 | if ( $method->isPHPInternal() ) { |
| 1376 | return; |
| 1377 | } |
| 1378 | $varLinks = self::getVarLinks( $method, $i ); |
| 1379 | if ( $varLinks === null ) { |
| 1380 | return; |
| 1381 | } |
| 1382 | |
| 1383 | $taintAdjusted = $taint->withOnly( SecurityCheckPlugin::ALL_TAINT ); |
| 1384 | |
| 1385 | foreach ( $varLinks as $var ) { |
| 1386 | $presTaint = $varLinks[$var]; |
| 1387 | if ( $var instanceof PassByReferenceVariable ) { |
| 1388 | // TODO This should become unnecessary once the TODO in handleMethodCall about postponing |
| 1389 | // handlePassByRef is resolved. |
| 1390 | $var = $var->getElement(); |
| 1391 | } |
| 1392 | assert( $var instanceof TypedElementInterface ); |
| 1393 | |
| 1394 | $taintToPropagate = $presTaint->asTaintednessForArgument( $taintAdjusted ); |
| 1395 | |
| 1396 | $adjustedCausedBy = self::getCausedByRawCloneOrEmpty( $var ) |
| 1397 | ->withTaintAddedToMethodArgLinks( $taintToPropagate, $method, $i ); |
| 1398 | self::setCausedByRaw( $var, $adjustedCausedBy ); |
| 1399 | $this->setTaintedness( $var, $taintToPropagate, false ); |
| 1400 | $this->addTaintError( $var, $taintToPropagate, null ); |
| 1401 | if ( $var instanceof GlobalVariable ) { |
| 1402 | $globalVar = $var->getElement(); |
| 1403 | $adjustedGlobalCausedBy = self::getCausedByRawCloneOrEmpty( $globalVar ) |
| 1404 | ->withTaintAddedToMethodArgLinks( $taintToPropagate, $method, $i ); |
| 1405 | self::setCausedByRaw( $globalVar, $adjustedGlobalCausedBy ); |
| 1406 | $this->setTaintedness( $globalVar, $taintToPropagate, false ); |
| 1407 | $this->addTaintError( $globalVar, $taintToPropagate, null ); |
| 1408 | } |
| 1409 | $this->mergeTaintError( $var, $error ); |
| 1410 | } |
| 1411 | } |
| 1412 | |
| 1413 | /** |
| 1414 | * Get the original cause of taint for the given func |
| 1415 | * |
| 1416 | * @param FunctionInterface $element |
| 1417 | * @return FunctionCausedByLines |
| 1418 | */ |
| 1419 | private function getCausedByLinesForFunc( FunctionInterface $element ): FunctionCausedByLines { |
| 1420 | $element = $this->getActualFuncWithCausedBy( $element ); |
| 1421 | return self::getFuncCausedByRawCloneOrEmpty( $element ); |
| 1422 | } |
| 1423 | |
| 1424 | /** |
| 1425 | * Given a phan element, get the actual element where caused-by data is stored. For instance, for methods, this |
| 1426 | * returns the defining methods. |
| 1427 | * |
| 1428 | * @param FunctionInterface $element |
| 1429 | * @return FunctionInterface |
| 1430 | */ |
| 1431 | private function getActualFuncWithCausedBy( FunctionInterface $element ): FunctionInterface { |
| 1432 | if ( SecurityCheckPlugin::$pluginInstance->builtinFuncHasTaint( $element->getFQSEN() ) ) { |
| 1433 | return $element; |
| 1434 | } |
| 1435 | $definingFunc = $this->getDefiningFuncIfDifferent( $element ); |
| 1436 | return $definingFunc ?? $element; |
| 1437 | } |
| 1438 | |
| 1439 | /** |
| 1440 | * Output a debug message to stdout. |
| 1441 | * |
| 1442 | * @param string $method __METHOD__ in question |
| 1443 | * @param string $msg debug message |
| 1444 | */ |
| 1445 | public function debug( $method, $msg ): void { |
| 1446 | if ( $this->debugOutput === null ) { |
| 1447 | $errorOutput = getenv( "SECCHECK_DEBUG" ); |
| 1448 | if ( $errorOutput && $errorOutput !== '-' ) { |
| 1449 | $this->debugOutput = fopen( $errorOutput, "w" ); |
| 1450 | } elseif ( $errorOutput === '-' ) { |
| 1451 | $this->debugOutput = '-'; |
| 1452 | } else { |
| 1453 | $this->debugOutput = false; |
| 1454 | } |
| 1455 | } |
| 1456 | $line = $method . "\33[1m " . $this->dbgInfo() . " \33[0m" . $msg . "\n"; |
| 1457 | if ( $this->debugOutput && $this->debugOutput !== '-' ) { |
| 1458 | fwrite( |
| 1459 | $this->debugOutput, |
| 1460 | $line |
| 1461 | ); |
| 1462 | } elseif ( $this->debugOutput === '-' ) { |
| 1463 | // @phan-suppress-next-line PhanPluginRemoveDebugEcho This is the only wanted debug echo |
| 1464 | echo $line; |
| 1465 | } |
| 1466 | } |
| 1467 | |
| 1468 | /** |
| 1469 | * Given an AST node that's a callable, try and determine what it is |
| 1470 | * |
| 1471 | * This is intended for functions that register callbacks. |
| 1472 | * |
| 1473 | * @param Node|mixed $node The thingy from AST expected to be a Callable |
| 1474 | * @return FunctionInterface|null |
| 1475 | */ |
| 1476 | protected function getCallableFromNode( $node ): ?FunctionInterface { |
| 1477 | if ( is_string( $node ) ) { |
| 1478 | // Easy case, 'Foo::Bar' |
| 1479 | // NOTE: ContextNode::getFunctionFromNode has a TODO about returning something here. |
| 1480 | // And also NOTE: 'self::methodname()' is not valid PHP. |
| 1481 | // TODO: We should probably emit a non-security issue in the missing case |
| 1482 | if ( strpos( $node, '::' ) === false ) { |
| 1483 | $callback = FullyQualifiedFunctionName::fromFullyQualifiedString( $node ); |
| 1484 | return $this->code_base->hasFunctionWithFQSEN( $callback ) |
| 1485 | ? $this->code_base->getFunctionByFQSEN( $callback ) |
| 1486 | : null; |
| 1487 | } |
| 1488 | $callback = FullyQualifiedMethodName::fromFullyQualifiedString( $node ); |
| 1489 | return $this->code_base->hasMethodWithFQSEN( $callback ) |
| 1490 | ? $this->code_base->getMethodByFQSEN( $callback ) |
| 1491 | : null; |
| 1492 | } |
| 1493 | if ( !$node instanceof Node ) { |
| 1494 | return null; |
| 1495 | } |
| 1496 | if ( |
| 1497 | $node->kind === \ast\AST_CLOSURE || |
| 1498 | $node->kind === \ast\AST_VAR || |
| 1499 | ( $node->kind === \ast\AST_ARRAY && count( $node->children ) === 2 ) |
| 1500 | ) { |
| 1501 | // Note: intentionally emitting any issues here. |
| 1502 | $funcs = $this->getCtxN( $node )->getFunctionFromNode(); |
| 1503 | return self::getFirstElmFromArrayOrGenerator( $funcs ); |
| 1504 | } |
| 1505 | return null; |
| 1506 | } |
| 1507 | |
| 1508 | /** |
| 1509 | * Utility function to get the first element from an iterable that can be either an array or a generator |
| 1510 | * @phan-template T |
| 1511 | * @param iterable $iter |
| 1512 | * @phan-param iterable<T> $iter |
| 1513 | * @return mixed|null Null if $iter is empty |
| 1514 | * @phan-return T|null |
| 1515 | */ |
| 1516 | protected static function getFirstElmFromArrayOrGenerator( iterable $iter ) { |
| 1517 | if ( is_array( $iter ) ) { |
| 1518 | return $iter ? $iter[0] : null; |
| 1519 | } |
| 1520 | assert( $iter instanceof Generator ); |
| 1521 | return $iter->current() ?: null; |
| 1522 | } |
| 1523 | |
| 1524 | /** |
| 1525 | * Get the issue names and severities given a taint, as well as the relevant taint type for each issue. |
| 1526 | * |
| 1527 | * @param int $combinedTaint The taint to warn for. I.e. The exec flags |
| 1528 | * from LHS shifted to non-exec bitwise AND'd with the rhs taint. |
| 1529 | * @return array[] List of issue type, severity, and taint type |
| 1530 | * @phan-return non-empty-list<array{0:string,1:int,2:int}> |
| 1531 | */ |
| 1532 | public function taintToIssuesAndSeverities( int $combinedTaint ): array { |
| 1533 | $issues = []; |
| 1534 | if ( $combinedTaint & SecurityCheckPlugin::HTML_TAINT ) { |
| 1535 | $issues[] = [ 'SecurityCheck-XSS', Issue::SEVERITY_NORMAL, SecurityCheckPlugin::HTML_TAINT ]; |
| 1536 | } |
| 1537 | if ( $combinedTaint & ( SecurityCheckPlugin::SQL_TAINT | SecurityCheckPlugin::SQL_NUMKEY_TAINT ) ) { |
| 1538 | $issues[] = [ |
| 1539 | 'SecurityCheck-SQLInjection', |
| 1540 | Issue::SEVERITY_CRITICAL, |
| 1541 | SecurityCheckPlugin::SQL_TAINT | SecurityCheckPlugin::SQL_NUMKEY_TAINT |
| 1542 | ]; |
| 1543 | } |
| 1544 | if ( $combinedTaint & SecurityCheckPlugin::SHELL_TAINT ) { |
| 1545 | $issues[] = [ 'SecurityCheck-ShellInjection', Issue::SEVERITY_CRITICAL, SecurityCheckPlugin::SHELL_TAINT ]; |
| 1546 | } |
| 1547 | if ( $combinedTaint & SecurityCheckPlugin::SERIALIZE_TAINT ) { |
| 1548 | // For now this is low because it seems to have a lot of false positives. |
| 1549 | $issues[] = [ |
| 1550 | 'SecurityCheck-PHPSerializeInjection', |
| 1551 | Issue::SEVERITY_NORMAL, |
| 1552 | SecurityCheckPlugin::SERIALIZE_TAINT |
| 1553 | ]; |
| 1554 | } |
| 1555 | if ( $combinedTaint & SecurityCheckPlugin::ESCAPED_TAINT ) { |
| 1556 | $issues[] = [ 'SecurityCheck-DoubleEscaped', Issue::SEVERITY_NORMAL, SecurityCheckPlugin::ESCAPED_TAINT ]; |
| 1557 | } |
| 1558 | if ( $combinedTaint & SecurityCheckPlugin::PATH_TAINT ) { |
| 1559 | $issues[] = [ 'SecurityCheck-PathTraversal', Issue::SEVERITY_CRITICAL, SecurityCheckPlugin::PATH_TAINT ]; |
| 1560 | } |
| 1561 | if ( $combinedTaint & SecurityCheckPlugin::CODE_TAINT ) { |
| 1562 | $issues[] = [ 'SecurityCheck-RCE', Issue::SEVERITY_CRITICAL, SecurityCheckPlugin::CODE_TAINT ]; |
| 1563 | } |
| 1564 | if ( $combinedTaint & SecurityCheckPlugin::REGEX_TAINT ) { |
| 1565 | $issues[] = [ 'SecurityCheck-ReDoS', Issue::SEVERITY_NORMAL, SecurityCheckPlugin::REGEX_TAINT ]; |
| 1566 | } |
| 1567 | if ( $combinedTaint & SecurityCheckPlugin::CUSTOM1_TAINT ) { |
| 1568 | $issues[] = [ 'SecurityCheck-CUSTOM1', Issue::SEVERITY_NORMAL, SecurityCheckPlugin::CUSTOM1_TAINT ]; |
| 1569 | } |
| 1570 | if ( $combinedTaint & SecurityCheckPlugin::CUSTOM2_TAINT ) { |
| 1571 | $issues[] = [ 'SecurityCheck-CUSTOM2', Issue::SEVERITY_NORMAL, SecurityCheckPlugin::CUSTOM2_TAINT ]; |
| 1572 | } |
| 1573 | |
| 1574 | return $issues; |
| 1575 | } |
| 1576 | |
| 1577 | /** |
| 1578 | * Simplified version of maybeEmitIssue which makes the following assumptions: |
| 1579 | * - The caller would compute the RHS taint only to feed it to maybeEmitIssue |
| 1580 | * - The message should be followed by caused-by lines |
| 1581 | * - These caused-by lines should be taken from the same object passed as RHS |
| 1582 | * - Only caused-by lines having the LHS taint should be included |
| 1583 | * If these conditions hold true, then this method should be preferred. |
| 1584 | * |
| 1585 | * @warning DO NOT use this method if the caller already needs to compute the RHS |
| 1586 | * taintedness! The taint would be computed twice! |
| 1587 | * |
| 1588 | * @param Taintedness $lhsTaint |
| 1589 | * @param mixed $rhsElement |
| 1590 | * @param string $msg |
| 1591 | * @param array $params Additional parameters for the message template |
| 1592 | * @phan-param list<string|FullyQualifiedFunctionLikeName> $params |
| 1593 | */ |
| 1594 | public function maybeEmitIssueSimplified( |
| 1595 | Taintedness $lhsTaint, |
| 1596 | $rhsElement, |
| 1597 | string $msg, |
| 1598 | array $params = [] |
| 1599 | ): void { |
| 1600 | $rhsTaint = $this->getTaintedness( $rhsElement ); |
| 1601 | $this->maybeEmitIssue( |
| 1602 | $lhsTaint, |
| 1603 | $rhsTaint->getTaintedness(), |
| 1604 | $msg . '{DETAILS}', |
| 1605 | array_merge( $params, [ $rhsTaint->getError() ] ) |
| 1606 | ); |
| 1607 | } |
| 1608 | |
| 1609 | /** |
| 1610 | * Emit an issue using the appropriate issue type |
| 1611 | * |
| 1612 | * If $this->overrideContext is set, it will use that for the |
| 1613 | * file/line number to report. This is meant as a hack, so that |
| 1614 | * in MW we can force hook related issues to be in the extension |
| 1615 | * instead of where the hook is called from in MW core. |
| 1616 | * |
| 1617 | * @param Taintedness $lhsTaint Taint of left hand side (or equivalent) |
| 1618 | * @param Taintedness $rhsTaint Taint of right hand side (or equivalent) |
| 1619 | * @param string $msg Issue description |
| 1620 | * @param array|Closure $msgParamsOrGetter Message parameters passed to emitIssue. Can also be a closure |
| 1621 | * that returns said parameters, for performance. |
| 1622 | * @phan-param list|Closure():list $msgParamsOrGetter |
| 1623 | */ |
| 1624 | public function maybeEmitIssue( |
| 1625 | Taintedness $lhsTaint, |
| 1626 | Taintedness $rhsTaint, |
| 1627 | string $msg, |
| 1628 | $msgParamsOrGetter |
| 1629 | ): void { |
| 1630 | $rhsIsUnknown = $rhsTaint->has( SecurityCheckPlugin::UNKNOWN_TAINT ); |
| 1631 | if ( $rhsIsUnknown && $lhsTaint->has( SecurityCheckPlugin::ALL_EXEC_TAINT ) ) { |
| 1632 | $combinedTaintInt = SecurityCheckPlugin::NO_TAINT; |
| 1633 | } else { |
| 1634 | $combinedTaint = Taintedness::intersectForSink( $lhsTaint, $rhsTaint ); |
| 1635 | if ( $combinedTaint->isSafe() ) { |
| 1636 | return; |
| 1637 | } |
| 1638 | $combinedTaintInt = Taintedness::flagsAsExecToYesTaint( $combinedTaint->get() ); |
| 1639 | } |
| 1640 | |
| 1641 | if ( |
| 1642 | ( $combinedTaintInt === SecurityCheckPlugin::NO_TAINT && $rhsIsUnknown ) || |
| 1643 | SecurityCheckPlugin::$pluginInstance->isFalsePositive( |
| 1644 | $combinedTaintInt, |
| 1645 | $msg, |
| 1646 | // FIXME should this be $this->overrideContext ? |
| 1647 | $this->context, |
| 1648 | $this->code_base |
| 1649 | ) |
| 1650 | ) { |
| 1651 | $issues = [ |
| 1652 | [ 'SecurityCheck-LikelyFalsePositive', Issue::SEVERITY_LOW, $combinedTaintInt ] |
| 1653 | ]; |
| 1654 | } else { |
| 1655 | $issues = $this->taintToIssuesAndSeverities( $combinedTaintInt ); |
| 1656 | } |
| 1657 | |
| 1658 | if ( !$issues ) { |
| 1659 | return; |
| 1660 | } |
| 1661 | |
| 1662 | $context = $this->context; |
| 1663 | if ( $this->overrideContext ) { |
| 1664 | // If we are overriding the file/line number, |
| 1665 | // report the original line number as well. |
| 1666 | $msg .= " (Originally at: $this->context)"; |
| 1667 | $context = $this->overrideContext; |
| 1668 | } |
| 1669 | |
| 1670 | $msgParams = $msgParamsOrGetter instanceof Closure ? $msgParamsOrGetter() : $msgParamsOrGetter; |
| 1671 | // Phan doesn't analyze the ternary correctly and thinks this might also be a closure. |
| 1672 | '@phan-var list $msgParams'; |
| 1673 | |
| 1674 | foreach ( $issues as [ $issueType, $severity, $relevantTaint ] ) { |
| 1675 | $curMsgParams = []; |
| 1676 | foreach ( $msgParams as $i => $par ) { |
| 1677 | $curMsgParams[$i] = $par instanceof CausedByLines |
| 1678 | ? $par->toStringForIssue( $relevantTaint ) |
| 1679 | : $par; |
| 1680 | } |
| 1681 | SecurityCheckPlugin::emitIssue( |
| 1682 | $this->code_base, |
| 1683 | $context, |
| 1684 | $issueType, |
| 1685 | $msg, |
| 1686 | $curMsgParams, |
| 1687 | $severity |
| 1688 | ); |
| 1689 | } |
| 1690 | } |
| 1691 | |
| 1692 | /** |
| 1693 | * Method to determine if a potential error isn't really real |
| 1694 | * |
| 1695 | * This is useful when a specific warning would have a side effect |
| 1696 | * and we want to know whether we should suppress the side effect in |
| 1697 | * addition to the warning. |
| 1698 | * |
| 1699 | * @param Taintedness $lhsTaint Must have at least one EXEC flag set |
| 1700 | * @return bool |
| 1701 | */ |
| 1702 | public function isIssueSuppressedOrFalsePositive( Taintedness $lhsTaint ): bool { |
| 1703 | $lhsTaintInt = $lhsTaint->get(); |
| 1704 | assert( ( $lhsTaintInt & SecurityCheckPlugin::ALL_EXEC_TAINT ) !== SecurityCheckPlugin::NO_TAINT ); |
| 1705 | $combinedTaint = Taintedness::flagsAsExecToYesTaint( $lhsTaintInt ); |
| 1706 | |
| 1707 | $issues = $this->taintToIssuesAndSeverities( $combinedTaint ); |
| 1708 | $context = $this->overrideContext ?: $this->context; |
| 1709 | foreach ( $issues as [ $issueType ] ) { |
| 1710 | if ( $context->hasSuppressIssue( $this->code_base, $issueType ) ) { |
| 1711 | return true; |
| 1712 | } |
| 1713 | } |
| 1714 | |
| 1715 | $msg = "[dummy msg for false positive check]"; |
| 1716 | return SecurityCheckPlugin::$pluginInstance->isFalsePositive( |
| 1717 | $combinedTaint, |
| 1718 | $msg, |
| 1719 | // not using $this->overrideContext to be consistent with maybeEmitIssue() |
| 1720 | $this->context, |
| 1721 | $this->code_base |
| 1722 | ); |
| 1723 | } |
| 1724 | |
| 1725 | /** |
| 1726 | * Somebody invokes a method or function (or something similar) |
| 1727 | * |
| 1728 | * This has to figure out: |
| 1729 | * Is the return value of the call tainted |
| 1730 | * Are any of the arguments tainted |
| 1731 | * Does the function do anything scary with its arguments |
| 1732 | * It also has to maintain quite a bit of book-keeping. |
| 1733 | * |
| 1734 | * @param FunctionInterface $func |
| 1735 | * @param FullyQualifiedFunctionLikeName $funcName |
| 1736 | * @param array $args Arguments to function/method |
| 1737 | * @phan-param array<Node|mixed> $args |
| 1738 | * @param bool $computePreserve Whether the caller wants to know which taintedness is preserved by this call |
| 1739 | * @param bool $isHookHandler Whether we're analyzing a hook handler for a Hooks::run call. |
| 1740 | * FIXME This is MW-specific |
| 1741 | * @return TaintednessWithError|null Taint The resulting taint of the expression, or null if |
| 1742 | * $computePreserve is false |
| 1743 | */ |
| 1744 | public function handleMethodCall( |
| 1745 | FunctionInterface $func, |
| 1746 | FullyQualifiedFunctionLikeName $funcName, |
| 1747 | array $args, |
| 1748 | bool $computePreserve = true, |
| 1749 | bool $isHookHandler = false |
| 1750 | ): ?TaintednessWithError { |
| 1751 | $taint = $this->getTaintOfFunction( $func ); |
| 1752 | $funcError = $this->getCausedByLinesForFunc( $func ); |
| 1753 | |
| 1754 | $preserveArgumentsData = []; |
| 1755 | foreach ( $args as $i => $argument ) { |
| 1756 | if ( !( $argument instanceof Node ) ) { |
| 1757 | // Literal value |
| 1758 | continue; |
| 1759 | } |
| 1760 | $curParFlags = $taint->getParamFlags( $i ); |
| 1761 | if ( ( $curParFlags & SecurityCheckPlugin::ARRAY_OK ) && $this->nodeIsArray( $argument ) ) { |
| 1762 | // This function specifies that arrays are always ok, so skip. |
| 1763 | continue; |
| 1764 | } |
| 1765 | |
| 1766 | if ( $argument->kind === \ast\AST_NAMED_ARG ) { |
| 1767 | [ $i, $argument, $argName ] = $this->translateNamedArg( $argument, $func ); |
| 1768 | if ( $i === null || !$argument instanceof Node ) { |
| 1769 | // Cannot find argument or it's literal |
| 1770 | continue; |
| 1771 | } |
| 1772 | $argName = "`$argName`"; |
| 1773 | } else { |
| 1774 | $argName = '#' . ( $i + 1 ); |
| 1775 | } |
| 1776 | |
| 1777 | $paramSinkTaint = $taint->getParamSinkTaint( $i ); |
| 1778 | $paramSinkError = $funcError->getParamSinkLines( $i ); |
| 1779 | |
| 1780 | $argTaintWithError = $this->getTaintednessNode( $argument ); |
| 1781 | $curArgTaintedness = $argTaintWithError->getTaintedness(); |
| 1782 | $baseArgError = $argTaintWithError->getError(); |
| 1783 | if ( |
| 1784 | $paramSinkTaint->has( SecurityCheckPlugin::SQL_NUMKEY_EXEC_TAINT ) |
| 1785 | && $curArgTaintedness->has( SecurityCheckPlugin::SQL_TAINT ) |
| 1786 | && $this->nodeCanBeString( $argument ) |
| 1787 | ) { |
| 1788 | // Special case to make NUMKEY work right for non-array values. |
| 1789 | // TODO Should consider if this is really best approach. |
| 1790 | $curArgTaintedness->add( SecurityCheckPlugin::SQL_NUMKEY_TAINT ); |
| 1791 | } |
| 1792 | |
| 1793 | $paramSinkTaint = SecurityCheckPlugin::$pluginInstance->modifyParamSinkTaint( |
| 1794 | $paramSinkTaint, |
| 1795 | $curArgTaintedness, |
| 1796 | $argument, |
| 1797 | $i, |
| 1798 | $func, |
| 1799 | $taint, |
| 1800 | $this->context, |
| 1801 | $this->code_base |
| 1802 | ); |
| 1803 | |
| 1804 | // Add a hook in order to special case for codebases. This is primarily used as a hack so that in mediawiki |
| 1805 | // the Message class doesn't have double escape taint if method takes Message|string. |
| 1806 | // TODO This is quite hacky. |
| 1807 | $curArgTaintedness = SecurityCheckPlugin::$pluginInstance->modifyArgTaint( |
| 1808 | $curArgTaintedness, |
| 1809 | $argument, |
| 1810 | $i, |
| 1811 | $func, |
| 1812 | $taint, |
| 1813 | $this->context, |
| 1814 | $this->code_base |
| 1815 | ); |
| 1816 | |
| 1817 | // TODO: We also need to handle the case where someFunc( $execArg ) for pass by reference where |
| 1818 | // the parameter is later executed outside the func. |
| 1819 | if ( $curArgTaintedness->has( SecurityCheckPlugin::ALL_TAINT ) ) { |
| 1820 | $this->markAllDependentVarsYes( $func, $i, $curArgTaintedness, $baseArgError ); |
| 1821 | } |
| 1822 | |
| 1823 | // We are doing something like evilMethod( $arg ); where $arg is a parameter to the current function. |
| 1824 | // So backpropagate that assigning to $arg can cause evilness. |
| 1825 | if ( !$paramSinkTaint->isSafe() ) { |
| 1826 | $this->backpropagateArgTaint( $argument, $paramSinkTaint, $paramSinkError ); |
| 1827 | } |
| 1828 | |
| 1829 | $param = $func->getParameterForCaller( $i ); |
| 1830 | // @todo Internal funcs that pass by reference. Should we assume that their variables are tainted? Most |
| 1831 | // common example is probably preg_match, which may very well be tainted much of the time. |
| 1832 | // TODO: Ideally this should happen after all args have been processed, so it would account for any |
| 1833 | // last-minute modification of the dependent elements (e.g. markAllDependentVarsYes) and would see the |
| 1834 | // "final" value for refTaint. Right now this is not possible because links tracked by |
| 1835 | // markAllDependentVarsYes are imprecise and would introduce false positives. |
| 1836 | if ( $param && $param->isPassByReference() && !$func->isPHPInternal() ) { |
| 1837 | $this->handlePassByRef( $func, $argument, $i, $isHookHandler ); |
| 1838 | } |
| 1839 | |
| 1840 | /** @phan-return list */ |
| 1841 | $issueArgsGetter = function () use ( |
| 1842 | $funcName, $argName, $argument, $paramSinkError, $baseArgError |
| 1843 | ): array { |
| 1844 | // Always include the ordinal (it helps for repeated arguments) |
| 1845 | $taintedArg = $argName; |
| 1846 | $argStr = ASTReverter::toShortString( $argument ); |
| 1847 | if ( strlen( $argStr ) < 25 ) { |
| 1848 | // If we have a short representation of the arg, include it as well. |
| 1849 | $taintedArg .= " (`$argStr`)"; |
| 1850 | } |
| 1851 | |
| 1852 | return [ |
| 1853 | $funcName, |
| 1854 | $this->getCurrentMethod(), |
| 1855 | $taintedArg, |
| 1856 | $paramSinkError, |
| 1857 | $baseArgError, |
| 1858 | ]; |
| 1859 | }; |
| 1860 | |
| 1861 | $this->maybeEmitIssue( |
| 1862 | $paramSinkTaint, |
| 1863 | $curArgTaintedness, |
| 1864 | "Calling method {FUNCTIONLIKE}() in {FUNCTIONLIKE}" . |
| 1865 | " that outputs using tainted argument {CODE}.{DETAILS}{DETAILS}", |
| 1866 | $issueArgsGetter |
| 1867 | ); |
| 1868 | |
| 1869 | $preserveArgumentsData[$i] = [ $curArgTaintedness, $baseArgError ]; |
| 1870 | } |
| 1871 | |
| 1872 | if ( !$computePreserve ) { |
| 1873 | return null; |
| 1874 | } |
| 1875 | |
| 1876 | $hardcodedPreservedTaint = $this->getHardcodedPreservedTaintForFunc( $func, $preserveArgumentsData ); |
| 1877 | if ( $hardcodedPreservedTaint ) { |
| 1878 | return $hardcodedPreservedTaint; |
| 1879 | } |
| 1880 | $overallTaint = $taint->getOverall(); |
| 1881 | $combinedArgTaint = Taintedness::newSafe(); |
| 1882 | $combinedArgErrors = new CausedByLines(); |
| 1883 | foreach ( $preserveArgumentsData as $i => [ $curArgTaintedness, $baseArgError ] ) { |
| 1884 | if ( $taint->hasParamPreserve( $i ) ) { |
| 1885 | $parTaint = $taint->getParamPreservedTaint( $i ); |
| 1886 | $preservedArgTaint = $parTaint->asTaintednessForArgument( $curArgTaintedness ); |
| 1887 | $curArgLinks = MethodLinks::newEmpty(); |
| 1888 | } elseif ( |
| 1889 | $overallTaint->has( SecurityCheckPlugin::PRESERVE_TAINT | SecurityCheckPlugin::UNKNOWN_TAINT ) |
| 1890 | ) { |
| 1891 | // No info for this specific parameter, but the overall function either preserves taint |
| 1892 | // when unspecified or is unknown. So just pass the taint through, destroying the shape. |
| 1893 | $preservedArgTaint = $curArgTaintedness->asCollapsed(); |
| 1894 | $curArgLinks = MethodLinks::newEmpty(); |
| 1895 | } else { |
| 1896 | // This parameter has no taint info. And overall this function doesn't depend on param |
| 1897 | // for taint and isn't unknown. So we consider this argument untainted. |
| 1898 | continue; |
| 1899 | } |
| 1900 | |
| 1901 | $combinedArgTaint->mergeWith( $preservedArgTaint ); |
| 1902 | $curArgError = $baseArgError->asIntersectedWithTaintedness( $preservedArgTaint ); |
| 1903 | $relevantParamError = $funcError->getParamPreservedLines( $i ) |
| 1904 | ->asPreservingTaintednessAndLinks( $preservedArgTaint, $curArgLinks ); |
| 1905 | $curArgError->mergeWith( $relevantParamError ); |
| 1906 | // NOTE: If any line inside the callee's body is responsible for preserving the taintedness of more |
| 1907 | // than one argument, it will appear once per preserved argument in the overall caused-by of the |
| 1908 | // call expression. This is probably a good thing, but can increase the length of caused-by lines. |
| 1909 | // TODO Something like T291379 might help here. |
| 1910 | $combinedArgErrors->mergeWith( $curArgError ); |
| 1911 | } |
| 1912 | |
| 1913 | $callTaintedness = $overallTaint->without( |
| 1914 | SecurityCheckPlugin::PRESERVE_TAINT | SecurityCheckPlugin::ALL_EXEC_TAINT |
| 1915 | ); |
| 1916 | $combinedArgTaint->remove( SecurityCheckPlugin::ALL_EXEC_TAINT ); |
| 1917 | $callTaintedness->mergeWith( $combinedArgTaint ); |
| 1918 | $callError = $funcError->getGenericLines()->asMergedWith( $combinedArgErrors ); |
| 1919 | return new TaintednessWithError( $callTaintedness, $callError, MethodLinks::newEmpty() ); |
| 1920 | } |
| 1921 | |
| 1922 | /** |
| 1923 | * @todo This should possibly be part of the public interface upstream |
| 1924 | * @see \Phan\Analysis\ArgumentType::analyzeParameterListForCallback |
| 1925 | * @param Node $argument |
| 1926 | * @param FunctionInterface $func |
| 1927 | * @return array |
| 1928 | * @phan-return array{0:int|null,1:Node|mixed,2:?string} |
| 1929 | */ |
| 1930 | private function translateNamedArg( Node $argument, FunctionInterface $func ): array { |
| 1931 | [ 'name' => $argName, 'expr' => $argExpr ] = $argument->children; |
| 1932 | assert( $argExpr !== null ); |
| 1933 | |
| 1934 | foreach ( $func->getRealParameterList() as $i => $parameter ) { |
| 1935 | if ( $parameter->getName() === $argName ) { |
| 1936 | return [ $i, $argExpr, $argName ]; |
| 1937 | } |
| 1938 | } |
| 1939 | return [ null, null, null ]; |
| 1940 | } |
| 1941 | |
| 1942 | /** |
| 1943 | * @param Node $argument |
| 1944 | * @param Taintedness $taint |
| 1945 | * @param CausedByLines|null $funcError |
| 1946 | * |
| 1947 | * @todo This has false negatives, because we don't collect function arguments in |
| 1948 | * getPhanObjsForNode (we'd have to pass option 'all'), so we can't handle e.g. array_merge |
| 1949 | * right now. However, collecting all args would create false positives with functions where |
| 1950 | * the arg taint isn't propagated to the return value. Ideally, we'd want to include an argument |
| 1951 | * iff the corresponding parameter passes $taint through. |
| 1952 | * |
| 1953 | * @note It's important that we don't backpropagate taintedness to every returned object in case |
| 1954 | * of function calls, but just props and the like (so excluding vars). See test 'toomanydeps'. |
| 1955 | */ |
| 1956 | protected function backpropagateArgTaint( |
| 1957 | Node $argument, |
| 1958 | Taintedness $taint, |
| 1959 | CausedByLines $funcError = null |
| 1960 | ): void { |
| 1961 | if ( $taint->has( SecurityCheckPlugin::SQL_NUMKEY_EXEC_TAINT ) ) { |
| 1962 | // Special case for numkey, we need to "filter" the argument. |
| 1963 | // TODO This doesn't return arrays with mixed keys. Currently, doing so would result |
| 1964 | // in arrays being considered as a unit, and the taint would be backpropagated to all |
| 1965 | // values, even ones with string keys. See TODO in elementCanBeNumkey |
| 1966 | |
| 1967 | // TODO This should be limited to the outer array, see TODO in backpropnumkey test |
| 1968 | // Note that this is true in general for NUMKEY taint, not just when backpropagating it |
| 1969 | $numkeyTaint = $taint->withOnly( SecurityCheckPlugin::SQL_NUMKEY_EXEC_TAINT ); |
| 1970 | $this->markAllDependentMethodsExecForNode( $argument, $numkeyTaint, $funcError, true ); |
| 1971 | $taint = $taint->without( SecurityCheckPlugin::SQL_NUMKEY_EXEC_TAINT ); |
| 1972 | } |
| 1973 | |
| 1974 | $this->markAllDependentMethodsExecForNode( $argument, $taint, $funcError ); |
| 1975 | } |
| 1976 | |
| 1977 | /** |
| 1978 | * Handle pass-by-ref params when examining a function call. Phan handles passbyref by reanalyzing |
| 1979 | * the method with PassByReferenceVariable objects instead of Parameters. These objects contain |
| 1980 | * the info about the param, but proxy all calls to the underlying argument object. |
| 1981 | * We cannot 100% copy that behaviour: inside the function body, the local variable for the pbr param |
| 1982 | * would have the same taintedness as the argument, and things like `echo $pbr` would emit an issue |
| 1983 | * inside the function, which is unwanted for now. Additionally, it's unclear how we'd add a caused-by |
| 1984 | * entry for the line of the function call. |
| 1985 | * Hence, instead of adding taintedness to the underlying argument, we put it in a separate prop, which is only |
| 1986 | * written but never read inside the function body. Then after the call was analyzed, this method moves |
| 1987 | * the taintedness from the "special" prop onto the normal taintedness prop. We do the same thing for links, |
| 1988 | * so as to infer which taintedness from the argument is preserved by the function. |
| 1989 | * TODO In the future we might want to really copy phan's approach, as that would allow us to delete some hacks, |
| 1990 | * and handle conditionals inside the function body more accurately. |
| 1991 | * |
| 1992 | * @param FunctionInterface $func |
| 1993 | * @param Node $argument |
| 1994 | * @param int $i Position of the param |
| 1995 | * @param bool $isHookHandler Whether we're analyzing a hook handler for a Hooks::run call. |
| 1996 | * FIXME This is MW-specific |
| 1997 | */ |
| 1998 | private function handlePassByRef( |
| 1999 | FunctionInterface $func, |
| 2000 | Node $argument, |
| 2001 | int $i, |
| 2002 | bool $isHookHandler |
| 2003 | ): void { |
| 2004 | $argObj = $this->getPassByRefObjFromNode( $argument ); |
| 2005 | if ( !$argObj ) { |
| 2006 | return; |
| 2007 | } |
| 2008 | $refTaint = self::getTaintednessRef( $argObj ); |
| 2009 | if ( !$refTaint ) { |
| 2010 | // If no ref taint was set, it's likely due to a recursive call or another instance where phan is not |
| 2011 | // reanalyzing the callee with PassByReferenceVariable objects. |
| 2012 | return; |
| 2013 | } |
| 2014 | |
| 2015 | $globalVarObj = $argObj instanceof GlobalVariable ? $argObj->getElement() : null; |
| 2016 | // Move the ref taintedness to the "actual" taintedness of the object |
| 2017 | // Note: We assume that the order in which hook handlers are called is nondeterministic, thus |
| 2018 | // we never override arg taint for reference params in this case. |
| 2019 | $overrideTaint = !( $argObj instanceof Property || $globalVarObj || $isHookHandler ); |
| 2020 | // Note, the call itself is only responsible if it adds some taintedness |
| 2021 | $errTaint = clone $refTaint; |
| 2022 | $refLinks = self::getMethodLinksRef( $argObj ); |
| 2023 | if ( $refLinks && $refLinks->hasDataForFuncAndParam( $func, $i ) ) { |
| 2024 | $addedTaint = $refLinks->asPreservedTaintednessForFuncParam( $func, $i ) |
| 2025 | ->asTaintednessForArgument( $this->getTaintednessPhanObj( $argObj ) ); |
| 2026 | $refTaint->mergeWith( $addedTaint ); |
| 2027 | } |
| 2028 | |
| 2029 | $this->setTaintedness( $argObj, $refTaint, $overrideTaint ); |
| 2030 | $this->addTaintError( $argObj, $errTaint, null ); |
| 2031 | if ( $globalVarObj ) { |
| 2032 | $this->setTaintedness( $globalVarObj, $refTaint, false ); |
| 2033 | $this->addTaintError( $globalVarObj, $errTaint, null ); |
| 2034 | } |
| 2035 | // We clear method links since the by-ref call might have modified them, and precise tracking is not |
| 2036 | // trivial to implement, and most probably not worth the effort. |
| 2037 | self::setMethodLinks( $argObj, MethodLinks::newEmpty() ); |
| 2038 | self::clearRefData( $argObj ); |
| 2039 | } |
| 2040 | |
| 2041 | /** |
| 2042 | * Given the node of an argument that is passed by reference, return a list of phan objects |
| 2043 | * corresponding to that node. |
| 2044 | * |
| 2045 | * @param Node $node |
| 2046 | * @return TypedElementInterface|null |
| 2047 | */ |
| 2048 | private function getPassByRefObjFromNode( Node $node ): ?TypedElementInterface { |
| 2049 | $cn = $this->getCtxN( $node ); |
| 2050 | |
| 2051 | switch ( $node->kind ) { |
| 2052 | case \ast\AST_PROP: |
| 2053 | case \ast\AST_STATIC_PROP: |
| 2054 | return $this->getPropFromNode( $node ); |
| 2055 | case \ast\AST_VAR: |
| 2056 | if ( Variable::isHardcodedGlobalVariableWithName( $cn->getVariableName() ) ) { |
| 2057 | return null; |
| 2058 | } |
| 2059 | try { |
| 2060 | return $cn->getVariable(); |
| 2061 | } catch ( NodeException | IssueException $_ ) { |
| 2062 | return null; |
| 2063 | } |
| 2064 | case \ast\AST_DIM: |
| 2065 | // Phan doesn't handle this case with PassByReferenceVariable objects, so nothing we can do anyway. |
| 2066 | return null; |
| 2067 | default: |
| 2068 | $this->debug( __METHOD__, 'Unhandled pass-by-ref case: ' . Debug::nodeName( $node ) ); |
| 2069 | return null; |
| 2070 | } |
| 2071 | } |
| 2072 | |
| 2073 | /** |
| 2074 | * Get the taintedness of the return value of $func (a special-cased internal PHP function) given the taintedness |
| 2075 | * of its arguments. Note that this doesn't handle passbyref parameters. If the function is not special-cased, |
| 2076 | * returns null. |
| 2077 | * |
| 2078 | * @param FunctionInterface $func |
| 2079 | * @param array<array<Taintedness|CausedByLines>> $preserveArgumentsData Actual taintedness and caused-by lines of |
| 2080 | * each argument. Literal arguments aren't included here. |
| 2081 | * @phan-param array<int,array{0:Taintedness,1:CausedByLines}> $preserveArgumentsData |
| 2082 | * @return TaintednessWithError|null |
| 2083 | */ |
| 2084 | private function getHardcodedPreservedTaintForFunc( |
| 2085 | FunctionInterface $func, |
| 2086 | array $preserveArgumentsData |
| 2087 | ): ?TaintednessWithError { |
| 2088 | switch ( ltrim( $func->getName(), '\\' ) ) { |
| 2089 | // Functions that return one element of the array (first and only parameter) |
| 2090 | case 'array_pop': |
| 2091 | case 'array_shift': |
| 2092 | case 'current': |
| 2093 | case 'end': |
| 2094 | case 'next': |
| 2095 | case 'pos': |
| 2096 | case 'prev': |
| 2097 | case 'reset': |
| 2098 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2099 | return TaintednessWithError::newEmpty(); |
| 2100 | } |
| 2101 | $taint = $preserveArgumentsData[0][0]->asValueFirstLevel(); |
| 2102 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2103 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2104 | case 'array_values': |
| 2105 | // Same taintedness as the original array (first and only param), but with safe keys and numkey. |
| 2106 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2107 | return TaintednessWithError::newEmpty(); |
| 2108 | } |
| 2109 | $taint = $preserveArgumentsData[0][0]->withoutKeys(); |
| 2110 | if ( $taint->has( SecurityCheckPlugin::SQL_TAINT ) ) { |
| 2111 | $taint->add( SecurityCheckPlugin::SQL_NUMKEY_TAINT ); |
| 2112 | } |
| 2113 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2114 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2115 | // Functions that return a key from the array (first and only parameter) |
| 2116 | case 'key': |
| 2117 | case 'array_key_first': |
| 2118 | case 'array_key_last': |
| 2119 | // array_keys returns all keys from the array (first param), and can also take two more parameters |
| 2120 | // that don't contribute to the resulting taintedness. |
| 2121 | case 'array_keys': |
| 2122 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2123 | return TaintednessWithError::newEmpty(); |
| 2124 | } |
| 2125 | $taint = $preserveArgumentsData[0][0]->asKeyForForeach(); |
| 2126 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2127 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2128 | case 'array_change_key_case': |
| 2129 | // The overall shape remains the same, but the keys of the outermost array (first param) have different |
| 2130 | // case. Second param (lower vs upper) is safe. |
| 2131 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2132 | return TaintednessWithError::newEmpty(); |
| 2133 | } |
| 2134 | // TODO: actually handle case changes! |
| 2135 | $taint = clone $preserveArgumentsData[0][0]; |
| 2136 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2137 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2138 | case 'array_flip': |
| 2139 | // Swaps keys and values of the array (first and only param) |
| 2140 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2141 | return TaintednessWithError::newEmpty(); |
| 2142 | } |
| 2143 | $taint = $preserveArgumentsData[0][0]->asKeyForForeach(); |
| 2144 | $taint->addKeysTaintedness( $preserveArgumentsData[0][0]->asValueFirstLevel()->get() ); |
| 2145 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2146 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2147 | case 'implode': |
| 2148 | case 'join': |
| 2149 | // This function can be called in three different ways: |
| 2150 | // - implode( $string, $array ) -> joins elements in $array using $string |
| 2151 | // - implode( $array ) -> joins elements in $array using the empty string |
| 2152 | // - implode( $array, $string ) -> same as the first one but inverted params, deprecated in PHP 7.4, |
| 2153 | // removed in PHP 8 |
| 2154 | // TODO: Right now we don't support the deprecated syntax; should we? |
| 2155 | if ( isset( $preserveArgumentsData[0] ) ) { |
| 2156 | $joinerTaint = $preserveArgumentsData[0][0]->asCollapsed(); |
| 2157 | $joinerError = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $joinerTaint ); |
| 2158 | } |
| 2159 | $combinedTaint = $joinerTaint ?? Taintedness::newSafe(); |
| 2160 | $combinedError = $joinerError ?? new CausedByLines(); |
| 2161 | if ( isset( $preserveArgumentsData[1] ) ) { |
| 2162 | $arrayTaint = $preserveArgumentsData[1][0]->withoutKeys()->asCollapsed(); |
| 2163 | $combinedTaint->mergeWith( $arrayTaint ); |
| 2164 | $combinedError->mergeWith( |
| 2165 | $preserveArgumentsData[1][1]->asIntersectedWithTaintedness( $arrayTaint ) |
| 2166 | ); |
| 2167 | } |
| 2168 | return new TaintednessWithError( $combinedTaint, $combinedError, MethodLinks::newEmpty() ); |
| 2169 | case 'array_fill': |
| 2170 | // array_fill( $start, $count, $value ) creates an array with $count copies of $value, starting |
| 2171 | // at key $start. The first two params are integers, and thus safe. |
| 2172 | if ( !isset( $preserveArgumentsData[2] ) ) { |
| 2173 | return TaintednessWithError::newEmpty(); |
| 2174 | } |
| 2175 | $preservedArgTaint = clone $preserveArgumentsData[2][0]; |
| 2176 | $taint = Taintedness::newSafe(); |
| 2177 | // TODO: We may actually be able to infer the actual keys, instead of setting as unknown |
| 2178 | $taint->setOffsetTaintedness( null, $preservedArgTaint ); |
| 2179 | // TODO: We should also add numkey if the argument has sql. |
| 2180 | $error = $preserveArgumentsData[2][1]->asIntersectedWithTaintedness( $preservedArgTaint ); |
| 2181 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2182 | case 'array_fill_keys': |
| 2183 | // array_fill_keys( $keys, $value ) creates an array whose keys are the element in $keys, and whose |
| 2184 | // values are all equal to $value. |
| 2185 | $taint = Taintedness::newSafe(); |
| 2186 | $error = new CausedByLines(); |
| 2187 | if ( isset( $preserveArgumentsData[0] ) ) { |
| 2188 | $keysTaintedness = $preserveArgumentsData[0][0]->asValueFirstLevel(); |
| 2189 | $taint->addKeysTaintedness( $keysTaintedness->get() ); |
| 2190 | $error->mergeWith( $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ) ); |
| 2191 | } |
| 2192 | if ( isset( $preserveArgumentsData[1] ) ) { |
| 2193 | $preservedValueTaint = $preserveArgumentsData[1][0]; |
| 2194 | $taint->setOffsetTaintedness( null, clone $preservedValueTaint ); |
| 2195 | $error->mergeWith( |
| 2196 | $preserveArgumentsData[1][1]->asIntersectedWithTaintedness( $preservedValueTaint ) |
| 2197 | ); |
| 2198 | } |
| 2199 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2200 | case 'array_combine': |
| 2201 | // array_fill_keys( $keys, $values ) creates an array whose keys are the element in $keys, and whose |
| 2202 | // values the elements in $values. |
| 2203 | $taint = Taintedness::newSafe(); |
| 2204 | $error = new CausedByLines(); |
| 2205 | if ( isset( $preserveArgumentsData[0] ) ) { |
| 2206 | $keysTaintedness = $preserveArgumentsData[0][0]->asValueFirstLevel(); |
| 2207 | $taint->addKeysTaintedness( $keysTaintedness->get() ); |
| 2208 | $error->mergeWith( $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ) ); |
| 2209 | } |
| 2210 | if ( isset( $preserveArgumentsData[1] ) ) { |
| 2211 | $valueTaint = $preserveArgumentsData[1][0]->withoutKeys(); |
| 2212 | $taint->mergeWith( $valueTaint ); |
| 2213 | $error->mergeWith( $preserveArgumentsData[1][1]->asIntersectedWithTaintedness( $valueTaint ) ); |
| 2214 | } |
| 2215 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2216 | case 'array_unique': |
| 2217 | // Removes duplicate from an array (first param). We can't tell what gets removed, and what's the effect |
| 2218 | // of this function on array keys. Second param is safe. |
| 2219 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2220 | return TaintednessWithError::newEmpty(); |
| 2221 | } |
| 2222 | $taint = $preserveArgumentsData[0][0]->asKnownKeysMadeUnknown(); |
| 2223 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2224 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2225 | case 'array_diff': |
| 2226 | case 'array_diff_assoc': |
| 2227 | // - array_diff( $arr, $x_1, ..., $x_n ) returns elements in $arr that are NOT in any of the $x_i. |
| 2228 | // The equality of two elements is determined by looking at their values. |
| 2229 | // Only the first argument contributes to the preserved taintedness. |
| 2230 | // - array_diff_assoc does the same, but two elements are considered equal if they have the same value |
| 2231 | // AND the same key. |
| 2232 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2233 | return TaintednessWithError::newEmpty(); |
| 2234 | } |
| 2235 | // We can't infer shape mutations because Taintedness doesn't keep track of the values, so just |
| 2236 | // return the taintedness of the first argument. |
| 2237 | $preservedArgTaint = clone $preserveArgumentsData[0][0]; |
| 2238 | return new TaintednessWithError( |
| 2239 | $preservedArgTaint, |
| 2240 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2241 | MethodLinks::newEmpty() |
| 2242 | ); |
| 2243 | case 'array_diff_key': |
| 2244 | // array_diff_key( $arr, $x_1, ..., $x_n ) is similar to array_diff, but here two elements are |
| 2245 | // considered equal if they have the same key (regardless of the value). |
| 2246 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2247 | return TaintednessWithError::newEmpty(); |
| 2248 | } |
| 2249 | /** @var Taintedness $taint */ |
| 2250 | [ $taint, $error ] = array_shift( $preserveArgumentsData ); |
| 2251 | $taint = clone $taint; |
| 2252 | foreach ( $preserveArgumentsData as $argData ) { |
| 2253 | $taint->removeKnownKeysFrom( $argData[0] ); |
| 2254 | // No argument besides the first one can contribute to caused-by lines, although |
| 2255 | // ideally we would remove the current error from $error. |
| 2256 | } |
| 2257 | // The shape is destroyed to avoid pretending that we know anything about the final shape of the array. |
| 2258 | return new TaintednessWithError( $taint->asKnownKeysMadeUnknown(), $error, MethodLinks::newEmpty() ); |
| 2259 | case 'array_intersect': |
| 2260 | case 'array_intersect_assoc': |
| 2261 | // - array_intersect( $arr_1, ..., $arr_n ) returns an array of elements that are in ALL of the $x_i. |
| 2262 | // The equality of two elements is determined by looking at their values. |
| 2263 | // Only values from the first array are used for the return value. |
| 2264 | // - array_intersect_assoc does the same, but two elements are considered equal if they have the same |
| 2265 | // value AND the same key. |
| 2266 | if ( !$preserveArgumentsData ) { |
| 2267 | return TaintednessWithError::newEmpty(); |
| 2268 | } |
| 2269 | // Note: we can't do an actual intersect on the values because Taintedness does not store them, but |
| 2270 | // intersecting the taintedness flags, although not perfect, is correct and approximates that. |
| 2271 | // The shape is destroyed to avoid pretending that we know anything about the final shape of the array. |
| 2272 | /** @var Taintedness $taint */ |
| 2273 | [ $taint, $error ] = array_shift( $preserveArgumentsData ); |
| 2274 | $taint = $taint->asKnownKeysMadeUnknown(); |
| 2275 | foreach ( $preserveArgumentsData as $argData ) { |
| 2276 | $taint->keepOnly( $argData[0]->get() ); |
| 2277 | // No argument besides the first one can contribute to caused-by lines, although |
| 2278 | // ideally we would intersect $error with the current error. |
| 2279 | } |
| 2280 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2281 | case 'array_intersect_key': |
| 2282 | // array_intersect_key( $arr, $x_1, ..., $x_n ) is similar to array_intersect, but here two elements are |
| 2283 | // considered equal if they have the same key (irregardless of the value). |
| 2284 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2285 | return TaintednessWithError::newEmpty(); |
| 2286 | } |
| 2287 | // We can't infer shape mutations because there might be unknown keys in either argument, so just |
| 2288 | // return the taintedness of the first argument. |
| 2289 | $preservedArgTaint = clone $preserveArgumentsData[0][0]; |
| 2290 | return new TaintednessWithError( |
| 2291 | $preservedArgTaint, |
| 2292 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2293 | MethodLinks::newEmpty() |
| 2294 | ); |
| 2295 | // TODO The last parameter of these functions is a callback, so probably hard to handle. They're also |
| 2296 | // variadic, so we'd need to know the arg type to analyze the callback. |
| 2297 | case 'array_diff_uassoc': |
| 2298 | case 'array_diff_ukey': |
| 2299 | case 'array_intersect_uassoc': |
| 2300 | case 'array_intersect_ukey': |
| 2301 | case 'array_udiff': |
| 2302 | case 'array_udiff_assoc': |
| 2303 | case 'array_uintersect': |
| 2304 | case 'array_uintersect_assoc': |
| 2305 | // The last two params of these are callbacks, so twice as hard |
| 2306 | case 'array_udiff_uassoc': |
| 2307 | case 'array_uintersect_uassoc': |
| 2308 | // Only the taintedness from first argument is preserved. |
| 2309 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2310 | return TaintednessWithError::newEmpty(); |
| 2311 | } |
| 2312 | $preservedArgTaint = clone $preserveArgumentsData[0][0]; |
| 2313 | return new TaintednessWithError( |
| 2314 | $preservedArgTaint, |
| 2315 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2316 | MethodLinks::newEmpty() |
| 2317 | ); |
| 2318 | case 'array_map': |
| 2319 | // array_map( $cb, $arr, $arr_1, ..., $arr_n ) returns the result of applying $cb to all the array |
| 2320 | // arguments, element by element. |
| 2321 | // TODO: Analyze the callback. For now we only preserve taintedness of array arguments. |
| 2322 | unset( $preserveArgumentsData[0] ); |
| 2323 | $taint = Taintedness::newSafe(); |
| 2324 | $error = new CausedByLines(); |
| 2325 | foreach ( $preserveArgumentsData as [ $argTaint, $argError ] ) { |
| 2326 | $preservedArgTaint = $argTaint->asCollapsed(); |
| 2327 | $taint->mergeWith( $preservedArgTaint ); |
| 2328 | $error->mergeWith( $argError->asIntersectedWithTaintedness( $preservedArgTaint ) ); |
| 2329 | } |
| 2330 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2331 | case 'array_filter': |
| 2332 | // array_filter( $arr, $cb, $mode ) filters the $arr by using $cb. |
| 2333 | // TODO: Analyze the callback. For now we preserve the whole taintedness of the array. |
| 2334 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2335 | return TaintednessWithError::newEmpty(); |
| 2336 | } |
| 2337 | $preservedArgTaint = $preserveArgumentsData[0][0]->asKnownKeysMadeUnknown(); |
| 2338 | return new TaintednessWithError( |
| 2339 | $preservedArgTaint, |
| 2340 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2341 | MethodLinks::newEmpty() |
| 2342 | ); |
| 2343 | case 'array_reduce': |
| 2344 | // array_reduce( $arr, $cb, $initial ) applies $cb to $arr to obtain a single value. |
| 2345 | // TODO: Analyze the callback. For now we preserve the whole taintedness of the array. |
| 2346 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2347 | return TaintednessWithError::newEmpty(); |
| 2348 | } |
| 2349 | $preservedArgTaint = $preserveArgumentsData[0][0]->asCollapsed(); |
| 2350 | return new TaintednessWithError( |
| 2351 | $preservedArgTaint, |
| 2352 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2353 | MethodLinks::newEmpty() |
| 2354 | ); |
| 2355 | case 'array_reverse': |
| 2356 | // array_reverse( $arr, $preserveKeys ) reverses the order of an array. String keys are always |
| 2357 | // preserved, the second param controls whether int keys are also preserved. |
| 2358 | // TODO: By knowing the value of the second arg, we could improve this by: |
| 2359 | // - Removing only int keys if false |
| 2360 | // - Preserving the whole shape if true |
| 2361 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2362 | return TaintednessWithError::newEmpty(); |
| 2363 | } |
| 2364 | $preservedArgTaint = $preserveArgumentsData[0][0]->asKnownKeysMadeUnknown(); |
| 2365 | return new TaintednessWithError( |
| 2366 | $preservedArgTaint, |
| 2367 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2368 | MethodLinks::newEmpty() |
| 2369 | ); |
| 2370 | case 'array_pad': |
| 2371 | // array_pad( $arr, $length, $val ) returns a copy of $arr padded to the size specified by $length |
| 2372 | // by adding copies of $val. |
| 2373 | if ( isset( $preserveArgumentsData[0] ) ) { |
| 2374 | $taint = clone $preserveArgumentsData[0][0]; |
| 2375 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2376 | } else { |
| 2377 | $taint = Taintedness::newSafe(); |
| 2378 | $error = new CausedByLines(); |
| 2379 | } |
| 2380 | if ( isset( $preserveArgumentsData[2] ) ) { |
| 2381 | $valArgTaint = $preserveArgumentsData[2][0]; |
| 2382 | $taint->setOffsetTaintedness( null, $valArgTaint ); |
| 2383 | $error->mergeWith( $preserveArgumentsData[2][1]->asIntersectedWithTaintedness( $valArgTaint ) ); |
| 2384 | } |
| 2385 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2386 | case 'array_slice': |
| 2387 | // array_slice( $arr, $offset, $len, $preserveKeys ) returns the segment of $arr starting at $offset |
| 2388 | // and of size $len. String keys are always preserved, $preserveKeys controls whether int keys |
| 2389 | // are also preserved. |
| 2390 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2391 | return TaintednessWithError::newEmpty(); |
| 2392 | } |
| 2393 | $preservedArgTaint = $preserveArgumentsData[0][0]->asKnownKeysMadeUnknown(); |
| 2394 | return new TaintednessWithError( |
| 2395 | $preservedArgTaint, |
| 2396 | $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $preservedArgTaint ), |
| 2397 | MethodLinks::newEmpty() |
| 2398 | ); |
| 2399 | case 'array_replace': |
| 2400 | // array_replace( $arr, $rep_1, ..., $rep_n ) returns a copy of $arr where each element is replaced |
| 2401 | // with the element having the same key in the rightmost argument. |
| 2402 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2403 | return TaintednessWithError::newEmpty(); |
| 2404 | } |
| 2405 | $firstArgData = array_shift( $preserveArgumentsData ); |
| 2406 | /** @var Taintedness $taint */ |
| 2407 | $taint = clone $firstArgData[0]; |
| 2408 | $error = $firstArgData[1]->asIntersectedWithTaintedness( $taint ); |
| 2409 | foreach ( $preserveArgumentsData as [ $argTaint, $argError ] ) { |
| 2410 | $taint->arrayReplace( $argTaint ); |
| 2411 | // Note: we may be adding too many caused-by lines here |
| 2412 | $error->mergeWith( $argError->asIntersectedWithTaintedness( $argTaint ) ); |
| 2413 | } |
| 2414 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2415 | case 'array_merge': |
| 2416 | // array_merge( $arr_1, ... $arr_n ) merges the given array arguments. If any two (or more) input arrays |
| 2417 | // have the same string key, the value from the rightmost argument with that key will be used. Integer |
| 2418 | // keys are always appended, and never replaced. Additionally, integer keys in the resulting array |
| 2419 | // will be renumbered incrementally starting from 0. |
| 2420 | if ( !$preserveArgumentsData ) { |
| 2421 | return TaintednessWithError::newEmpty(); |
| 2422 | } |
| 2423 | /** @var Taintedness $taint */ |
| 2424 | [ $taint, $error ] = array_shift( $preserveArgumentsData ); |
| 2425 | foreach ( $preserveArgumentsData as [ $argTaint, $argError ] ) { |
| 2426 | $taint->arrayMerge( $argTaint ); |
| 2427 | $error->mergeWith( $argError->asIntersectedWithTaintedness( $argTaint ) ); |
| 2428 | } |
| 2429 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2430 | // TODO Handle these with recursion. |
| 2431 | case 'array_merge_recursive': |
| 2432 | case 'array_replace_recursive': |
| 2433 | $taint = Taintedness::newSafe(); |
| 2434 | $error = new CausedByLines(); |
| 2435 | foreach ( $preserveArgumentsData as [ $curArgTaintedness, $baseArgError ] ) { |
| 2436 | $preservedArgTaint = $curArgTaintedness->asKnownKeysMadeUnknown(); |
| 2437 | $taint->mergeWith( $preservedArgTaint ); |
| 2438 | $error->mergeWith( $baseArgError->asIntersectedWithTaintedness( $preservedArgTaint ) ); |
| 2439 | } |
| 2440 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2441 | case 'array_chunk': |
| 2442 | // array_chunk( $array, $length, $preserve_keys = false ) returns a list of chunks of $array. The keys |
| 2443 | // in each chunk are the same of $array if $preserve_keys is true. Else, they're just numbers. |
| 2444 | if ( !isset( $preserveArgumentsData[0] ) ) { |
| 2445 | return TaintednessWithError::newEmpty(); |
| 2446 | } |
| 2447 | $taint = Taintedness::newSafe(); |
| 2448 | // TODO: Check value of $preserve_keys to determine the key taintedness more accurately. |
| 2449 | // For now, we just assume that keys are preserved. |
| 2450 | $taint->setOffsetTaintedness( null, $preserveArgumentsData[0][0]->asKnownKeysMadeUnknown() ); |
| 2451 | $error = $preserveArgumentsData[0][1]->asIntersectedWithTaintedness( $taint ); |
| 2452 | return new TaintednessWithError( $taint, $error, MethodLinks::newEmpty() ); |
| 2453 | default: |
| 2454 | return null; |
| 2455 | } |
| 2456 | } |
| 2457 | |
| 2458 | /** |
| 2459 | * Given a binary operator, compute which taint will be preserved. Safe ops don't preserve |
| 2460 | * any taint, whereas unsafe ops will preserve all taints. The taint of a binop is basically |
| 2461 | * ( lhs_taint | rhs_taint ) & taint_mask |
| 2462 | * |
| 2463 | * @warning This method should avoid computing the taint of $lhs and $rhs, because it might be |
| 2464 | * called in preorder, but it would trigger a postorder visit. |
| 2465 | * |
| 2466 | * @param Node $opNode |
| 2467 | * @param Node|mixed $lhs Either a Node or a scalar |
| 2468 | * @param Node|mixed $rhs Either a Node or a scalar |
| 2469 | * @return int |
| 2470 | */ |
| 2471 | protected function getBinOpTaintMask( Node $opNode, $lhs, $rhs ): int { |
| 2472 | static $safeBinOps = [ |
| 2473 | \ast\flags\BINARY_BOOL_XOR, |
| 2474 | \ast\flags\BINARY_DIV, |
| 2475 | \ast\flags\BINARY_IS_EQUAL, |
| 2476 | \ast\flags\BINARY_IS_IDENTICAL, |
| 2477 | \ast\flags\BINARY_IS_NOT_EQUAL, |
| 2478 | \ast\flags\BINARY_IS_NOT_IDENTICAL, |
| 2479 | \ast\flags\BINARY_IS_SMALLER, |
| 2480 | \ast\flags\BINARY_IS_SMALLER_OR_EQUAL, |
| 2481 | \ast\flags\BINARY_MOD, |
| 2482 | \ast\flags\BINARY_MUL, |
| 2483 | \ast\flags\BINARY_POW, |
| 2484 | // BINARY_ADD handled below due to array addition. |
| 2485 | \ast\flags\BINARY_SUB, |
| 2486 | \ast\flags\BINARY_BOOL_AND, |
| 2487 | \ast\flags\BINARY_BOOL_OR, |
| 2488 | \ast\flags\BINARY_IS_GREATER, |
| 2489 | \ast\flags\BINARY_IS_GREATER_OR_EQUAL, |
| 2490 | \ast\flags\BINARY_SHIFT_LEFT, |
| 2491 | \ast\flags\BINARY_SHIFT_RIGHT, |
| 2492 | \ast\flags\BINARY_SPACESHIP, |
| 2493 | ]; |
| 2494 | |
| 2495 | // This list is mostly used for debugging purposes |
| 2496 | static $knownUnsafeOps = [ |
| 2497 | \ast\flags\BINARY_ADD, |
| 2498 | \ast\flags\BINARY_CONCAT, |
| 2499 | \ast\flags\BINARY_COALESCE, |
| 2500 | // The result of bitwise ops can be a string, so we err on the side of caution. |
| 2501 | \ast\flags\BINARY_BITWISE_AND, |
| 2502 | \ast\flags\BINARY_BITWISE_OR, |
| 2503 | \ast\flags\BINARY_BITWISE_XOR, |
| 2504 | ]; |
| 2505 | |
| 2506 | if ( in_array( $opNode->flags, $safeBinOps, true ) ) { |
| 2507 | return SecurityCheckPlugin::NO_TAINT; |
| 2508 | } |
| 2509 | if ( |
| 2510 | $opNode->flags === \ast\flags\BINARY_ADD && |
| 2511 | ( !$this->nodeCanBeArray( $lhs ) || !$this->nodeCanBeArray( $rhs ) ) |
| 2512 | ) { |
| 2513 | // Array addition is the only way `+` can preserve taintedness; if at least one operand |
| 2514 | // is definitely NOT an array, then the result will be an integer, or a fatal error will |
| 2515 | // occurr (depending on the other operand). Note that if we cannot be 100% sure that the |
| 2516 | // node cannot be an array (e.g. if it has mixed type), we err on the side of caution and |
| 2517 | // consider it potentially tainted. |
| 2518 | return SecurityCheckPlugin::NO_TAINT; |
| 2519 | } |
| 2520 | |
| 2521 | if ( !in_array( $opNode->flags, $knownUnsafeOps, true ) ) { |
| 2522 | $this->debug( |
| 2523 | __METHOD__, |
| 2524 | 'Unhandled binop ' . Debug::astFlagDescription( $opNode->flags, $opNode->kind ) |
| 2525 | ); |
| 2526 | } |
| 2527 | |
| 2528 | return SecurityCheckPlugin::ALL_TAINT_FLAGS; |
| 2529 | } |
| 2530 | |
| 2531 | /** |
| 2532 | * Get the possible UnionType of a node, without emitting issues. |
| 2533 | * |
| 2534 | * @param Node $node |
| 2535 | * @return UnionType|null |
| 2536 | */ |
| 2537 | protected function getNodeType( Node $node ): ?UnionType { |
| 2538 | // Don't emit issues, as this method might be called e.g. on a LHS (see T249647). |
| 2539 | // FIXME Improve this. Is it still necessary now that we cache taintedness? |
| 2540 | $catchIssueException = false; |
| 2541 | // And since we don't emit issues, use a cloned context so phan won't cache any union type. In particular, |
| 2542 | // in the event of possibly-undefined union types, the issue about a variable being possibly undeclared would |
| 2543 | // get lost, because we don't emit it, and phan will cache the union type without the undefined bit. |
| 2544 | $ctx = clone $this->context; |
| 2545 | try { |
| 2546 | return UnionTypeVisitor::unionTypeFromNode( |
| 2547 | $this->code_base, |
| 2548 | $ctx, |
| 2549 | $node, |
| 2550 | $catchIssueException |
| 2551 | ); |
| 2552 | } catch ( IssueException $e ) { |
| 2553 | $this->debug( __METHOD__, "Got error " . $this->getDebugInfo( $e ) ); |
| 2554 | return null; |
| 2555 | } |
| 2556 | } |
| 2557 | |
| 2558 | /** |
| 2559 | * Given a Node, is it an array? (And definitely not a string) |
| 2560 | * |
| 2561 | * @param Node|mixed $node A node object or simple value from AST tree |
| 2562 | * @return bool Is it an array? |
| 2563 | */ |
| 2564 | protected function nodeIsArray( $node ): bool { |
| 2565 | if ( !( $node instanceof Node ) ) { |
| 2566 | // simple literal |
| 2567 | return false; |
| 2568 | } |
| 2569 | if ( $node->kind === \ast\AST_ARRAY ) { |
| 2570 | // Exit early in the simple case. |
| 2571 | return true; |
| 2572 | } |
| 2573 | $type = $this->getNodeType( $node ); |
| 2574 | return $type && $type->hasArrayLike( $this->code_base ) && |
| 2575 | !$type->hasMixedOrNonEmptyMixedType() && !$type->hasStringType(); |
| 2576 | } |
| 2577 | |
| 2578 | /** |
| 2579 | * Can $node potentially be an array? |
| 2580 | * |
| 2581 | * @param Node|mixed $node |
| 2582 | * @return bool |
| 2583 | */ |
| 2584 | protected function nodeCanBeArray( $node ): bool { |
| 2585 | if ( !( $node instanceof Node ) ) { |
| 2586 | return is_array( $node ); |
| 2587 | } |
| 2588 | $type = $this->getNodeType( $node ); |
| 2589 | if ( !$type ) { |
| 2590 | return true; |
| 2591 | } |
| 2592 | $type = $type->getRealUnionType(); |
| 2593 | return $type->hasArrayLike( $this->code_base ) || $type->hasMixedOrNonEmptyMixedType() || $type->isEmpty(); |
| 2594 | } |
| 2595 | |
| 2596 | /** |
| 2597 | * Given a Node, is it a string? |
| 2598 | * |
| 2599 | * @todo Unclear if this should return true for things that can |
| 2600 | * autocast to a string (e.g. ints) |
| 2601 | * @param Node|mixed $node A node object or simple value from AST tree |
| 2602 | * @return bool Is it a string? |
| 2603 | */ |
| 2604 | protected function nodeCanBeString( $node ): bool { |
| 2605 | if ( !( $node instanceof Node ) ) { |
| 2606 | // simple literal |
| 2607 | return is_string( $node ); |
| 2608 | } |
| 2609 | $type = $this->getNodeType( $node ); |
| 2610 | // @todo Should having mixed type result in returning false here? |
| 2611 | return $type && $type->hasStringType(); |
| 2612 | } |
| 2613 | |
| 2614 | /** |
| 2615 | * @param TypedElementInterface $el |
| 2616 | * @param bool $definitely Whether $el is *definitely* numkey, not just possibly |
| 2617 | * @return bool |
| 2618 | */ |
| 2619 | protected function elementCanBeNumkey( TypedElementInterface $el, bool $definitely ): bool { |
| 2620 | $type = $el->getUnionType()->getRealUnionType(); |
| 2621 | if ( $type->hasMixedOrNonEmptyMixedType() || $type->isEmpty() ) { |
| 2622 | return !$definitely; |
| 2623 | } |
| 2624 | if ( !$type->hasArray() ) { |
| 2625 | return false; |
| 2626 | } |
| 2627 | |
| 2628 | $keyTypes = GenericArrayType::keyUnionTypeFromTypeSetStrict( $el->getUnionType()->getRealTypeSet() ); |
| 2629 | // NOTE: This might lead to false positives if the array has mixed keys, but since we're talking about |
| 2630 | // SQLi, we prefer false positives. Also, the mixed keys case isn't fully handled, see backpropagateArgTaint |
| 2631 | return $definitely |
| 2632 | ? $keyTypes === GenericArrayType::KEY_INT |
| 2633 | : ( $keyTypes & GenericArrayType::KEY_INT ) !== 0; |
| 2634 | } |
| 2635 | |
| 2636 | /** |
| 2637 | * Given a Node that is used as array key, can the key be integer? |
| 2638 | * Floats are not considered ints here. |
| 2639 | * Note: this method cannot be 100% accurate. First, we don't use the real type, so we may have a false positive |
| 2640 | * if e.g. a parameter is annotated as string but the argument is an int. Second, even if something has a real type |
| 2641 | * and is not an integer, it could be a string that gets autocast to an integer. |
| 2642 | * |
| 2643 | * @param Node|mixed $node A node object or simple value from AST tree |
| 2644 | * @return bool Is it an int? |
| 2645 | * @fixme A lot of duplication with other similar methods... |
| 2646 | */ |
| 2647 | protected function nodeCanBeIntKey( $node ): bool { |
| 2648 | if ( !( $node instanceof Node ) ) { |
| 2649 | // simple number; make sure to include float here for PHP 8.1 compat: T307504 |
| 2650 | if ( is_int( $node ) || is_float( $node ) ) { |
| 2651 | return true; |
| 2652 | } |
| 2653 | // Strings that are canonical representation of numbers are coerced to int keys. |
| 2654 | $testArr = [ $node => 'foo' ]; |
| 2655 | $key = key( $testArr ); |
| 2656 | return is_int( $key ); |
| 2657 | } |
| 2658 | $type = $this->getNodeType( $node ); |
| 2659 | if ( !$type ) { |
| 2660 | return true; |
| 2661 | } |
| 2662 | return $type->hasIntType() || $type->hasMixedOrNonEmptyMixedType() || $type->isEmpty(); |
| 2663 | } |
| 2664 | |
| 2665 | /** |
| 2666 | * Get the phan objects from the return line of a Func/Method |
| 2667 | * |
| 2668 | * This is primarily used to handle the case where a method |
| 2669 | * returns a member (e.g. return $this->foo), and then something |
| 2670 | * else does something evil with it - e.g. echo $someObj->getFoo(). |
| 2671 | * This allows keeping track that $this->foo is outputted, so if |
| 2672 | * somewhere else in the code someone calls $someObj->setFoo( $unsafe ) |
| 2673 | * we can trigger a warning. |
| 2674 | * |
| 2675 | * This of course will only work in simple cases. It may also potentially |
| 2676 | * have false positives if one instance is used solely for escaped stuff |
| 2677 | * and a different instance is used for unsafe values that are later |
| 2678 | * escaped, as all the different instances are treated the same. |
| 2679 | * |
| 2680 | * It needs the return statement to be trivial (e.g. return $this->foo;). It |
| 2681 | * will not work even with something as simple as $a = $this->foo; return $a; |
| 2682 | * However, this code path will only happen if the plugin encounters the |
| 2683 | * code to output the value prior to reading the code that sets the value to |
| 2684 | * something evil. The other code path where the set happens first is much |
| 2685 | * more robust and hopefully the more common code path. |
| 2686 | * |
| 2687 | * @param FunctionInterface $func The function/method. Must use Analyzable trait |
| 2688 | * @return TypedElementInterface[] An array of phan objects |
| 2689 | */ |
| 2690 | public function getReturnObjsOfFunc( FunctionInterface $func ): array { |
| 2691 | $retObjs = self::getRetObjs( $func ); |
| 2692 | if ( $retObjs === null ) { |
| 2693 | // We still have to see the function. Analyze it now. |
| 2694 | $this->analyzeFunc( $func ); |
| 2695 | $retObjs = self::getRetObjs( $func ); |
| 2696 | if ( $retObjs === null ) { |
| 2697 | // If it still doesn't exist, perhaps we reached the recursion limit, or it may be a recursive |
| 2698 | // function, or a kind of function that we can't handle. |
| 2699 | return []; |
| 2700 | } |
| 2701 | } |
| 2702 | |
| 2703 | // Note that if a function is recursively calling itself, this list might be incomplete. |
| 2704 | // This could be remediated with another dynamic property (e.g. retObjsCollected), initialized |
| 2705 | // inside visitMethod in preorder, and set to true inside visitMethod in postorder. |
| 2706 | // It would be pointless, though, as returning a partial list is better than returning no list. |
| 2707 | return array_filter( |
| 2708 | $retObjs, |
| 2709 | static function ( TypedElementInterface $el ): bool { |
| 2710 | return !( $el instanceof Variable ); |
| 2711 | } |
| 2712 | ); |
| 2713 | } |
| 2714 | |
| 2715 | /** |
| 2716 | * Shorthand to check if $child is subclass of $parent. |
| 2717 | * |
| 2718 | * @param FullyQualifiedClassName $child |
| 2719 | * @param FullyQualifiedClassName $parent |
| 2720 | * @param CodeBase $codeBase |
| 2721 | * @return bool |
| 2722 | */ |
| 2723 | public static function isSubclassOf( |
| 2724 | FullyQualifiedClassName $child, |
| 2725 | FullyQualifiedClassName $parent, |
| 2726 | CodeBase $codeBase |
| 2727 | ): bool { |
| 2728 | return $child->asType()->asExpandedTypes( $codeBase )->hasType( $parent->asType() ); |
| 2729 | } |
| 2730 | } |