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| 1 | <?php declare( strict_types=1 ); |
| 2 | |
| 3 | namespace SecurityCheckPlugin; |
| 4 | |
| 5 | use ast\Node; |
| 6 | |
| 7 | /** |
| 8 | * Value object used to store taintedness. This should always be used to manipulate taintedness values, |
| 9 | * instead of directly using taint constants directly (except for comparisons etc.). |
| 10 | * |
| 11 | * Note that this class should be used as copy-on-write (like phan's UnionType), so in-place |
| 12 | * manipulation should never be done on phan objects. |
| 13 | */ |
| 14 | class Taintedness { |
| 15 | /** @var int Combination of the class constants */ |
| 16 | private $flags; |
| 17 | |
| 18 | /** @var self[] Taintedness for each possible array element */ |
| 19 | private $dimTaint = []; |
| 20 | |
| 21 | /** @var int Taintedness of the array keys */ |
| 22 | private $keysTaint = SecurityCheckPlugin::NO_TAINT; |
| 23 | |
| 24 | /** |
| 25 | * @var self|null Taintedness for array elements that we couldn't attribute to any key |
| 26 | */ |
| 27 | private $unknownDimsTaint; |
| 28 | |
| 29 | /** |
| 30 | * @param int $val One of the class constants |
| 31 | */ |
| 32 | public function __construct( int $val ) { |
| 33 | $this->flags = $val; |
| 34 | } |
| 35 | |
| 36 | // Common creation shortcuts |
| 37 | |
| 38 | /** |
| 39 | * @return self |
| 40 | */ |
| 41 | public static function newSafe(): self { |
| 42 | return new self( SecurityCheckPlugin::NO_TAINT ); |
| 43 | } |
| 44 | |
| 45 | /** |
| 46 | * @return self |
| 47 | */ |
| 48 | public static function newUnknown(): self { |
| 49 | return new self( SecurityCheckPlugin::UNKNOWN_TAINT ); |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * @return self |
| 54 | */ |
| 55 | public static function newTainted(): self { |
| 56 | return new self( SecurityCheckPlugin::YES_TAINT ); |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * @param Taintedness[] $values |
| 61 | * @return self |
| 62 | */ |
| 63 | public static function newFromArray( array $values ): self { |
| 64 | $ret = self::newSafe(); |
| 65 | foreach ( $values as $key => $value ) { |
| 66 | assert( $value instanceof self ); |
| 67 | $ret->setOffsetTaintedness( $key, $value ); |
| 68 | } |
| 69 | return $ret; |
| 70 | } |
| 71 | |
| 72 | /** |
| 73 | * Get a numeric representation of the taint stored in this object. This includes own taint, |
| 74 | * array keys and whatnot. |
| 75 | * @note This should almost NEVER be used outside of this class! Use accessors as much as possible! |
| 76 | * |
| 77 | * @return int |
| 78 | */ |
| 79 | public function get(): int { |
| 80 | $ret = $this->flags | $this->getAllKeysTaint() | $this->keysTaint; |
| 81 | return $this->unknownDimsTaint ? ( $ret | $this->unknownDimsTaint->get() ) : $ret; |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * Get a flattened version of this object, with any taint from keys etc. collapsed into flags |
| 86 | * @return $this |
| 87 | */ |
| 88 | public function asCollapsed(): self { |
| 89 | return new self( $this->get() ); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Returns a copy of this object where the taintedness of every known key has been reassigned |
| 94 | * to unknown keys. |
| 95 | * @return self |
| 96 | */ |
| 97 | public function asKnownKeysMadeUnknown(): self { |
| 98 | $ret = new self( $this->flags ); |
| 99 | $ret->keysTaint = $this->keysTaint; |
| 100 | $ret->unknownDimsTaint = $this->unknownDimsTaint; |
| 101 | if ( $this->dimTaint ) { |
| 102 | $ret->unknownDimsTaint ??= self::newSafe(); |
| 103 | foreach ( $this->dimTaint as $keyTaint ) { |
| 104 | $ret->unknownDimsTaint->mergeWith( $keyTaint ); |
| 105 | } |
| 106 | } |
| 107 | return $ret; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Recursively extract the taintedness from each key. |
| 112 | * |
| 113 | * @return int |
| 114 | */ |
| 115 | private function getAllKeysTaint(): int { |
| 116 | $ret = SecurityCheckPlugin::NO_TAINT; |
| 117 | foreach ( $this->dimTaint as $val ) { |
| 118 | $ret |= $val->get(); |
| 119 | } |
| 120 | return $ret; |
| 121 | } |
| 122 | |
| 123 | // Value manipulation |
| 124 | |
| 125 | /** |
| 126 | * Add the given taint to this object's flags, *without* creating a clone |
| 127 | * @see Taintedness::with() if you need a clone |
| 128 | * @see Taintedness::mergeWith() if you want to preserve the whole shape |
| 129 | * |
| 130 | * @param int $taint |
| 131 | */ |
| 132 | public function add( int $taint ): void { |
| 133 | // TODO: Should this clear UNKNOWN_TAINT if its present only in one of the args? |
| 134 | $this->flags |= $taint; |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * Returns a copy of this object, with the bits in $other added to flags. |
| 139 | * @see Taintedness::add() for the in-place version |
| 140 | * @see Taintedness::asMergedWith() if you want to preserve the whole shape |
| 141 | * |
| 142 | * @param int $other |
| 143 | * @return $this |
| 144 | */ |
| 145 | public function with( int $other ): self { |
| 146 | $ret = clone $this; |
| 147 | $ret->add( $other ); |
| 148 | return $ret; |
| 149 | } |
| 150 | |
| 151 | /** |
| 152 | * Recursively remove the given taint from this object, *without* creating a clone |
| 153 | * @see Taintedness::without() if you need a clone |
| 154 | * |
| 155 | * @param int $other |
| 156 | */ |
| 157 | public function remove( int $other ): void { |
| 158 | $this->keepOnly( ~$other ); |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * Returns a copy of this object, with the bits in $other removed recursively. |
| 163 | * @see Taintedness::remove() for the in-place version |
| 164 | * |
| 165 | * @param int $other |
| 166 | * @return $this |
| 167 | */ |
| 168 | public function without( int $other ): self { |
| 169 | $ret = clone $this; |
| 170 | $ret->remove( $other ); |
| 171 | return $ret; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Check whether this object has the given flag, recursively. |
| 176 | * @note If $taint has more than one flag, this will check for at least one, not all. |
| 177 | * |
| 178 | * @param int $taint |
| 179 | * @return bool |
| 180 | */ |
| 181 | public function has( int $taint ): bool { |
| 182 | // Avoid using get() for performance |
| 183 | if ( ( $this->flags & $taint ) !== SecurityCheckPlugin::NO_TAINT ) { |
| 184 | return true; |
| 185 | } |
| 186 | if ( ( $this->keysTaint & $taint ) !== SecurityCheckPlugin::NO_TAINT ) { |
| 187 | return true; |
| 188 | } |
| 189 | if ( $this->unknownDimsTaint && $this->unknownDimsTaint->has( $taint ) ) { |
| 190 | return true; |
| 191 | } |
| 192 | foreach ( $this->dimTaint as $val ) { |
| 193 | if ( $val->has( $taint ) ) { |
| 194 | return true; |
| 195 | } |
| 196 | } |
| 197 | return false; |
| 198 | } |
| 199 | |
| 200 | /** |
| 201 | * Keep only the taint in $taint, recursively, preserving the shape and without creating a copy. |
| 202 | * @see Taintedness::withOnly if you need a clone |
| 203 | * |
| 204 | * @param int $taint |
| 205 | */ |
| 206 | public function keepOnly( int $taint ): void { |
| 207 | $this->flags &= $taint; |
| 208 | if ( $this->unknownDimsTaint ) { |
| 209 | $this->unknownDimsTaint->keepOnly( $taint ); |
| 210 | } |
| 211 | $this->keysTaint &= $taint; |
| 212 | foreach ( $this->dimTaint as $val ) { |
| 213 | $val->keepOnly( $taint ); |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | /** |
| 218 | * Returns a copy of this object, with only the taint in $taint kept (recursively, preserving the shape) |
| 219 | * @see Taintedness::keepOnly() for the in-place version |
| 220 | * |
| 221 | * @param int $other |
| 222 | * @return $this |
| 223 | */ |
| 224 | public function withOnly( int $other ): self { |
| 225 | $ret = clone $this; |
| 226 | $ret->keepOnly( $other ); |
| 227 | return $ret; |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Intersect the taintedness of a value against that of a sink, to later determine whether the |
| 232 | * expression is safe. In case of function calls, $sink is the param taint and $value is the arg taint. |
| 233 | * |
| 234 | * @note The order of the arguments is important! This method preserves the shape of $sink, not $value. |
| 235 | * |
| 236 | * @note The order of the arguments is important! This method preserves the shape of $sink, not $value. |
| 237 | * |
| 238 | * @param Taintedness $sink |
| 239 | * @param Taintedness $value |
| 240 | * @return self |
| 241 | */ |
| 242 | public static function intersectForSink( self $sink, self $value ): self { |
| 243 | $intersect = new self( SecurityCheckPlugin::NO_TAINT ); |
| 244 | // If the sink has non-zero flags, intersect it with the whole other side. This particularly preserves |
| 245 | // the shape of $sink, discarding anything from $value if the sink has a NO_TAINT in that position. |
| 246 | if ( $sink->flags & SecurityCheckPlugin::SQL_NUMKEY_EXEC_TAINT ) { |
| 247 | // Special case: NUMKEY is only for the outer array |
| 248 | $rightFlags = $value->flags | $value->keysTaint; |
| 249 | if ( $value->keysTaint & SecurityCheckPlugin::SQL_TAINT ) { |
| 250 | // FIXME HACK: If keys are tainted, add numkey. This assumes that numkey is really only used for |
| 251 | // Database methods, where keys are never escaped. |
| 252 | $rightFlags |= SecurityCheckPlugin::SQL_NUMKEY_TAINT; |
| 253 | } |
| 254 | $rightFlags |= ( $value->getAllKeysTaint() & ~SecurityCheckPlugin::SQL_NUMKEY_TAINT ); |
| 255 | if ( $value->unknownDimsTaint ) { |
| 256 | $rightFlags |= $value->unknownDimsTaint->get() & ~SecurityCheckPlugin::SQL_NUMKEY_TAINT; |
| 257 | } |
| 258 | $intersect->flags = $sink->flags & ( ( $rightFlags & SecurityCheckPlugin::ALL_TAINT ) << 1 ); |
| 259 | } elseif ( $sink->flags ) { |
| 260 | $intersect->flags = $sink->flags & ( ( $value->get() & SecurityCheckPlugin::ALL_TAINT ) << 1 ); |
| 261 | } |
| 262 | if ( $sink->unknownDimsTaint ) { |
| 263 | $intersect->unknownDimsTaint = self::intersectForSink( |
| 264 | $sink->unknownDimsTaint, |
| 265 | $value->asValueFirstLevel() |
| 266 | ); |
| 267 | } |
| 268 | $valueKeysAsExec = ( ( $value->keysTaint | $value->flags ) & SecurityCheckPlugin::ALL_TAINT ) << 1; |
| 269 | $intersect->keysTaint = $sink->keysTaint & $valueKeysAsExec; |
| 270 | foreach ( $sink->dimTaint as $key => $dTaint ) { |
| 271 | $intersect->dimTaint[$key] = self::intersectForSink( |
| 272 | $dTaint, |
| 273 | $value->getTaintednessForOffsetOrWhole( $key ) |
| 274 | ); |
| 275 | } |
| 276 | return $intersect; |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * Removes offset data from $this for all known offsets of $other, in place. |
| 281 | * |
| 282 | * @param Taintedness $other |
| 283 | * @return void |
| 284 | */ |
| 285 | public function removeKnownKeysFrom( self $other ): void { |
| 286 | foreach ( $other->dimTaint as $key => $_ ) { |
| 287 | unset( $this->dimTaint[$key] ); |
| 288 | } |
| 289 | if ( |
| 290 | ( $this->flags & SecurityCheckPlugin::SQL_NUMKEY_TAINT ) && |
| 291 | !$this->has( SecurityCheckPlugin::SQL_TAINT ) |
| 292 | ) { |
| 293 | // Note that this adjustment is not guaranteed to happen immediately after the removal of the last |
| 294 | // integer key. For instance, in [ 0 => unsafe, 'foo' => unsafe ], if only the element 0 is removed, |
| 295 | // this branch will not run because 'foo' still contributes sql taint. |
| 296 | $this->flags &= ~SecurityCheckPlugin::SQL_NUMKEY_TAINT; |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | /** |
| 301 | * Merge this object with $other, recursively and without creating a copy. |
| 302 | * @see Taintedness::asMergedWith() if you need a copy |
| 303 | * |
| 304 | * @param Taintedness $other |
| 305 | */ |
| 306 | public function mergeWith( self $other ): void { |
| 307 | $this->flags |= $other->flags; |
| 308 | if ( $other->unknownDimsTaint && !$this->unknownDimsTaint ) { |
| 309 | $this->unknownDimsTaint = $other->unknownDimsTaint; |
| 310 | } elseif ( $other->unknownDimsTaint ) { |
| 311 | $this->unknownDimsTaint->mergeWith( $other->unknownDimsTaint ); |
| 312 | } |
| 313 | $this->keysTaint |= $other->keysTaint; |
| 314 | foreach ( $other->dimTaint as $key => $val ) { |
| 315 | if ( !isset( $this->dimTaint[$key] ) ) { |
| 316 | $this->dimTaint[$key] = clone $val; |
| 317 | } else { |
| 318 | $this->dimTaint[$key]->mergeWith( $val ); |
| 319 | } |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | /** |
| 324 | * Merge this object with $other, recursively, creating a copy. |
| 325 | * @see Taintedness::mergeWith() for in-place merge |
| 326 | * |
| 327 | * @param Taintedness $other |
| 328 | * @return $this |
| 329 | */ |
| 330 | public function asMergedWith( self $other ): self { |
| 331 | $ret = clone $this; |
| 332 | $ret->mergeWith( $other ); |
| 333 | return $ret; |
| 334 | } |
| 335 | |
| 336 | // Offsets taintedness |
| 337 | |
| 338 | /** |
| 339 | * Set the taintedness for $offset to $value, in place |
| 340 | * |
| 341 | * @param Node|mixed $offset Node or a scalar value, already resolved |
| 342 | * @param Taintedness $value |
| 343 | */ |
| 344 | public function setOffsetTaintedness( $offset, self $value ): void { |
| 345 | if ( is_scalar( $offset ) ) { |
| 346 | $this->dimTaint[$offset] = $value; |
| 347 | } else { |
| 348 | $this->unknownDimsTaint ??= self::newSafe(); |
| 349 | $this->unknownDimsTaint->mergeWith( $value ); |
| 350 | } |
| 351 | } |
| 352 | |
| 353 | /** |
| 354 | * Adds the bits in $value to the taintedness of the keys |
| 355 | * @param int $value |
| 356 | */ |
| 357 | public function addKeysTaintedness( int $value ): void { |
| 358 | $this->keysTaint |= $value; |
| 359 | } |
| 360 | |
| 361 | /** |
| 362 | * @param self $other |
| 363 | * @param int $depth |
| 364 | * @return self |
| 365 | */ |
| 366 | public function asMergedForAssignment( self $other, int $depth ): self { |
| 367 | if ( $depth === 0 ) { |
| 368 | return $other; |
| 369 | } |
| 370 | $ret = clone $this; |
| 371 | $ret->flags |= $other->flags; |
| 372 | $ret->keysTaint |= $other->keysTaint; |
| 373 | if ( !$ret->unknownDimsTaint ) { |
| 374 | $ret->unknownDimsTaint = $other->unknownDimsTaint; |
| 375 | } elseif ( $other->unknownDimsTaint ) { |
| 376 | $ret->unknownDimsTaint->mergeWith( $other->unknownDimsTaint ); |
| 377 | } |
| 378 | foreach ( $other->dimTaint as $k => $v ) { |
| 379 | $ret->dimTaint[$k] = isset( $ret->dimTaint[$k] ) |
| 380 | ? $ret->dimTaint[$k]->asMergedForAssignment( $v, $depth - 1 ) |
| 381 | : $v; |
| 382 | } |
| 383 | return $ret; |
| 384 | } |
| 385 | |
| 386 | /** |
| 387 | * Apply an array addition with $other |
| 388 | * |
| 389 | * @param Taintedness $other |
| 390 | */ |
| 391 | public function arrayPlus( self $other ): void { |
| 392 | $this->flags |= $other->flags; |
| 393 | if ( $other->unknownDimsTaint && !$this->unknownDimsTaint ) { |
| 394 | $this->unknownDimsTaint = $other->unknownDimsTaint; |
| 395 | } elseif ( $other->unknownDimsTaint ) { |
| 396 | $this->unknownDimsTaint->mergeWith( $other->unknownDimsTaint ); |
| 397 | } |
| 398 | $this->keysTaint |= $other->keysTaint; |
| 399 | // This is not recursive because array addition isn't |
| 400 | $this->dimTaint += $other->dimTaint; |
| 401 | } |
| 402 | |
| 403 | /** |
| 404 | * Apply the effect of array addition and return a clone of $this |
| 405 | * |
| 406 | * @param Taintedness $other |
| 407 | * @return $this |
| 408 | */ |
| 409 | public function asArrayPlusWith( self $other ): self { |
| 410 | $ret = clone $this; |
| 411 | $ret->arrayPlus( $other ); |
| 412 | return $ret; |
| 413 | } |
| 414 | |
| 415 | /** |
| 416 | * Get the taintedness for the given offset, if set. If $offset could not be resolved, this |
| 417 | * will return the whole object, with taint from unknown keys added. If the offset is not known, |
| 418 | * it will return a new Taintedness object without the original shape, and with taint from |
| 419 | * unknown keys added. |
| 420 | * |
| 421 | * @param Node|string|int|bool|float|null $offset |
| 422 | * @return self Always a copy |
| 423 | */ |
| 424 | public function getTaintednessForOffsetOrWhole( $offset ): self { |
| 425 | if ( !is_scalar( $offset ) ) { |
| 426 | return $this->asValueFirstLevel(); |
| 427 | } |
| 428 | if ( isset( $this->dimTaint[$offset] ) ) { |
| 429 | if ( $this->unknownDimsTaint ) { |
| 430 | $ret = $this->dimTaint[$offset]->asMergedWith( $this->unknownDimsTaint ); |
| 431 | } else { |
| 432 | $ret = $this->dimTaint[$offset]; |
| 433 | } |
| 434 | } elseif ( $this->unknownDimsTaint ) { |
| 435 | $ret = $this->unknownDimsTaint; |
| 436 | } else { |
| 437 | return new self( $this->flags ); |
| 438 | } |
| 439 | $ret->flags |= $this->flags; |
| 440 | return $ret; |
| 441 | } |
| 442 | |
| 443 | /** |
| 444 | * Create a new object with $this at the given $offset (if scalar) or as unknown object. |
| 445 | * |
| 446 | * @param Node|string|int|bool|float|null $offset |
| 447 | * @param int|null $offsetTaint If available, will be used as key taint |
| 448 | * @return self Always a copy |
| 449 | */ |
| 450 | public function asMaybeMovedAtOffset( $offset, int $offsetTaint = null ): self { |
| 451 | $ret = self::newSafe(); |
| 452 | if ( $offsetTaint !== null ) { |
| 453 | $ret->keysTaint = $offsetTaint; |
| 454 | } |
| 455 | if ( $offset instanceof Node || $offset === null ) { |
| 456 | $ret->unknownDimsTaint = clone $this; |
| 457 | } else { |
| 458 | $ret->dimTaint[$offset] = clone $this; |
| 459 | } |
| 460 | return $ret; |
| 461 | } |
| 462 | |
| 463 | /** |
| 464 | * Get a representation of this taint at the first depth level. For instance, this can be used in a foreach |
| 465 | * assignment for the value. Own taint and unknown keys taint are preserved, and then we merge in recursively |
| 466 | * all the current keys. |
| 467 | * |
| 468 | * @return $this |
| 469 | */ |
| 470 | public function asValueFirstLevel(): self { |
| 471 | $ret = new self( $this->flags & ~SecurityCheckPlugin::SQL_NUMKEY_TAINT ); |
| 472 | if ( $this->unknownDimsTaint ) { |
| 473 | $ret->mergeWith( $this->unknownDimsTaint ); |
| 474 | } |
| 475 | foreach ( $this->dimTaint as $val ) { |
| 476 | $ret->mergeWith( $val ); |
| 477 | } |
| 478 | return $ret; |
| 479 | } |
| 480 | |
| 481 | /** |
| 482 | * Creates a copy of this object without the given key |
| 483 | * @param string|int|bool|float $key |
| 484 | * @return $this |
| 485 | */ |
| 486 | public function withoutKey( $key ): self { |
| 487 | $ret = clone $this; |
| 488 | unset( $ret->dimTaint[$key] ); |
| 489 | if ( |
| 490 | ( $ret->flags & SecurityCheckPlugin::SQL_NUMKEY_TAINT ) && |
| 491 | !$ret->has( SecurityCheckPlugin::SQL_TAINT ) |
| 492 | ) { |
| 493 | // Note that this adjustment is not guaranteed to happen immediately after the removal of the last |
| 494 | // integer key. For instance, in [ 0 => unsafe, 'foo' => unsafe ], if the element 0 is removed, |
| 495 | // this branch will not run because 'foo' still contributes sql taint. |
| 496 | $ret->flags &= ~SecurityCheckPlugin::SQL_NUMKEY_TAINT; |
| 497 | } |
| 498 | return $ret; |
| 499 | } |
| 500 | |
| 501 | /** |
| 502 | * Creates a copy of this object without known offsets, and without keysTaint |
| 503 | * @return $this |
| 504 | */ |
| 505 | public function withoutKeys(): self { |
| 506 | $ret = clone $this; |
| 507 | $ret->keysTaint = SecurityCheckPlugin::NO_TAINT; |
| 508 | if ( !$ret->dimTaint ) { |
| 509 | return $ret; |
| 510 | } |
| 511 | $ret->unknownDimsTaint ??= self::newSafe(); |
| 512 | foreach ( $ret->dimTaint as $dim => $taint ) { |
| 513 | $ret->unknownDimsTaint->mergeWith( $taint ); |
| 514 | unset( $ret->dimTaint[$dim] ); |
| 515 | } |
| 516 | return $ret; |
| 517 | } |
| 518 | |
| 519 | /** |
| 520 | * Get a representation of this taint to be used in a foreach assignment for the key |
| 521 | * |
| 522 | * @return $this |
| 523 | */ |
| 524 | public function asKeyForForeach(): self { |
| 525 | return new self( ( $this->keysTaint | $this->flags ) & ~SecurityCheckPlugin::SQL_NUMKEY_TAINT ); |
| 526 | } |
| 527 | |
| 528 | /** |
| 529 | * Applies an array_replace operations to $this, in place. |
| 530 | * |
| 531 | * @param Taintedness $other |
| 532 | * @return void |
| 533 | */ |
| 534 | public function arrayReplace( self $other ): void { |
| 535 | $this->flags |= $other->flags; |
| 536 | $this->dimTaint = array_replace( $this->dimTaint, $other->dimTaint ); |
| 537 | if ( $other->unknownDimsTaint ) { |
| 538 | if ( $this->unknownDimsTaint ) { |
| 539 | $this->unknownDimsTaint->mergeWith( $other->unknownDimsTaint ); |
| 540 | } else { |
| 541 | $this->unknownDimsTaint = $other->unknownDimsTaint; |
| 542 | } |
| 543 | } |
| 544 | } |
| 545 | |
| 546 | /** |
| 547 | * Applies an array_merge operations to $this, in place. |
| 548 | * |
| 549 | * @param Taintedness $other |
| 550 | * @return void |
| 551 | */ |
| 552 | public function arrayMerge( self $other ): void { |
| 553 | // First merge the known elements |
| 554 | $this->dimTaint = array_merge( $this->dimTaint, $other->dimTaint ); |
| 555 | // Then merge general flags, key flags, and any unknown keys |
| 556 | $this->flags |= $other->flags; |
| 557 | $this->keysTaint |= $other->keysTaint; |
| 558 | $this->unknownDimsTaint ??= new self( SecurityCheckPlugin::NO_TAINT ); |
| 559 | if ( $other->unknownDimsTaint ) { |
| 560 | $this->unknownDimsTaint->mergeWith( $other->unknownDimsTaint ); |
| 561 | } |
| 562 | // Finally, move taintedness from int keys to unknown |
| 563 | foreach ( $this->dimTaint as $k => $val ) { |
| 564 | if ( is_int( $k ) ) { |
| 565 | $this->unknownDimsTaint->mergeWith( $val ); |
| 566 | unset( $this->dimTaint[$k] ); |
| 567 | } |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | // Conversion/checks shortcuts |
| 572 | |
| 573 | /** |
| 574 | * Check whether this object has no taintedness. |
| 575 | * |
| 576 | * @return bool |
| 577 | */ |
| 578 | public function isSafe(): bool { |
| 579 | // Don't use get() for performance |
| 580 | if ( $this->flags !== SecurityCheckPlugin::NO_TAINT ) { |
| 581 | return false; |
| 582 | } |
| 583 | if ( $this->keysTaint !== SecurityCheckPlugin::NO_TAINT ) { |
| 584 | return false; |
| 585 | } |
| 586 | if ( $this->unknownDimsTaint && !$this->unknownDimsTaint->isSafe() ) { |
| 587 | return false; |
| 588 | } |
| 589 | foreach ( $this->dimTaint as $val ) { |
| 590 | if ( !$val->isSafe() ) { |
| 591 | return false; |
| 592 | } |
| 593 | } |
| 594 | return true; |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * Convert exec to yes taint recursively. Special flags like UNKNOWN or INAPPLICABLE are discarded. |
| 599 | * Any YES flags are also discarded. Note that this returns a copy of the |
| 600 | * original object. The shape is preserved. |
| 601 | * |
| 602 | * @warning This function is nilpotent: f^2(x) = 0 |
| 603 | * |
| 604 | * @return self |
| 605 | */ |
| 606 | public function asExecToYesTaint(): self { |
| 607 | $ret = new self( ( $this->flags & SecurityCheckPlugin::ALL_EXEC_TAINT ) >> 1 ); |
| 608 | if ( $this->unknownDimsTaint ) { |
| 609 | $ret->unknownDimsTaint = $this->unknownDimsTaint->asExecToYesTaint(); |
| 610 | } |
| 611 | $ret->keysTaint = ( $this->keysTaint & SecurityCheckPlugin::ALL_EXEC_TAINT ) >> 1; |
| 612 | foreach ( $this->dimTaint as $k => $val ) { |
| 613 | $ret->dimTaint[$k] = $val->asExecToYesTaint(); |
| 614 | } |
| 615 | return $ret; |
| 616 | } |
| 617 | |
| 618 | /** |
| 619 | * Convert the yes taint bits to corresponding exec taint bits recursively. |
| 620 | * Any UNKNOWN_TAINT or INAPPLICABLE_TAINT is discarded. Note that this returns a copy of the |
| 621 | * original object. The shape is preserved. |
| 622 | * |
| 623 | * @warning This function is nilpotent: f^2(x) = 0 |
| 624 | * |
| 625 | * @return self |
| 626 | * @suppress PhanUnreferencedPublicMethod For consistency |
| 627 | */ |
| 628 | public function asYesToExecTaint(): self { |
| 629 | $ret = new self( ( $this->flags & SecurityCheckPlugin::ALL_TAINT ) << 1 ); |
| 630 | if ( $this->unknownDimsTaint ) { |
| 631 | $ret->unknownDimsTaint = $this->unknownDimsTaint->asYesToExecTaint(); |
| 632 | } |
| 633 | $ret->keysTaint = ( $this->keysTaint & SecurityCheckPlugin::ALL_TAINT ) << 1; |
| 634 | foreach ( $this->dimTaint as $k => $val ) { |
| 635 | $ret->dimTaint[$k] = $val->asYesToExecTaint(); |
| 636 | } |
| 637 | return $ret; |
| 638 | } |
| 639 | |
| 640 | /** |
| 641 | * @param ParamLinksOffsets $offsets |
| 642 | * @return self |
| 643 | */ |
| 644 | public function asMovedAtRelevantOffsetsForBackprop( ParamLinksOffsets $offsets ): self { |
| 645 | $offsetsFlags = $offsets->getFlags(); |
| 646 | $ret = $offsetsFlags ? |
| 647 | $this->withOnly( ( $offsetsFlags & SecurityCheckPlugin::ALL_TAINT ) << 1 ) |
| 648 | : new self( SecurityCheckPlugin::NO_TAINT ); |
| 649 | foreach ( $offsets->getDims() as $k => $val ) { |
| 650 | $newVal = $this->asMovedAtRelevantOffsetsForBackprop( $val ); |
| 651 | if ( isset( $ret->dimTaint[$k] ) ) { |
| 652 | $ret->dimTaint[$k]->mergeWith( $newVal ); |
| 653 | } else { |
| 654 | $ret->dimTaint[$k] = $newVal; |
| 655 | } |
| 656 | } |
| 657 | $unknownOffs = $offsets->getUnknown(); |
| 658 | if ( $unknownOffs ) { |
| 659 | $newVal = $this->asMovedAtRelevantOffsetsForBackprop( $unknownOffs ); |
| 660 | if ( $ret->unknownDimsTaint ) { |
| 661 | $ret->unknownDimsTaint->mergeWith( $newVal ); |
| 662 | } else { |
| 663 | $ret->unknownDimsTaint = $newVal; |
| 664 | } |
| 665 | } |
| 666 | $ret->keysTaint |= ( $this->flags | $this->keysTaint ) & |
| 667 | ( ( $offsets->getKeysFlags() & SecurityCheckPlugin::ALL_TAINT ) << 1 ); |
| 668 | return $ret; |
| 669 | } |
| 670 | |
| 671 | /** |
| 672 | * Utility method to convert some flags from EXEC to YES. Note that this is not used internally |
| 673 | * to avoid the unnecessary overhead of a function call in hot code. |
| 674 | * |
| 675 | * @param int $flags |
| 676 | * @return int |
| 677 | */ |
| 678 | public static function flagsAsExecToYesTaint( int $flags ): int { |
| 679 | return ( $flags & SecurityCheckPlugin::ALL_EXEC_TAINT ) >> 1; |
| 680 | } |
| 681 | |
| 682 | /** |
| 683 | * Utility method to convert some flags from YES to EXEC. Note that this is not used internally |
| 684 | * to avoid the unnecessary overhead of a function call in hot code. |
| 685 | * |
| 686 | * @param int $flags |
| 687 | * @return int |
| 688 | */ |
| 689 | public static function flagsAsYesToExecTaint( int $flags ): int { |
| 690 | return ( $flags & SecurityCheckPlugin::ALL_TAINT ) << 1; |
| 691 | } |
| 692 | |
| 693 | /** |
| 694 | * @todo This method shouldn't be necessary (ideally) |
| 695 | * @return PreservedTaintedness |
| 696 | */ |
| 697 | public function asPreservedTaintedness(): PreservedTaintedness { |
| 698 | $ret = new PreservedTaintedness( new ParamLinksOffsets( $this->flags ) ); |
| 699 | foreach ( $this->dimTaint as $k => $val ) { |
| 700 | $ret->setOffsetTaintedness( $k, $val->asPreservedTaintedness() ); |
| 701 | } |
| 702 | if ( $this->unknownDimsTaint ) { |
| 703 | $ret->setOffsetTaintedness( null, $this->unknownDimsTaint->asPreservedTaintedness() ); |
| 704 | } |
| 705 | return $ret; |
| 706 | } |
| 707 | |
| 708 | /** |
| 709 | * Given some method links, returns a list of pairs of LinksSet and Taintedness objects, where the taintedness |
| 710 | * in each pair should be backpropagated to the links in the LinksSet. |
| 711 | * |
| 712 | * @param MethodLinks $links |
| 713 | * @return array<array<LinksSet|Taintedness>> |
| 714 | * @phan-return array<array{0:LinksSet,1:Taintedness}> |
| 715 | */ |
| 716 | public function decomposeForLinks( MethodLinks $links ): array { |
| 717 | $pairs = []; |
| 718 | |
| 719 | if ( $this->flags !== SecurityCheckPlugin::NO_TAINT ) { |
| 720 | $pairs[] = [ $links->getLinksCollapsing(), new self( $this->flags ) ]; |
| 721 | } |
| 722 | |
| 723 | if ( $this->keysTaint !== SecurityCheckPlugin::NO_TAINT ) { |
| 724 | $pairs[] = [ $links->asKeyForForeach()->getLinksCollapsing(), $this->asKeyForForeach() ]; |
| 725 | } |
| 726 | |
| 727 | foreach ( $this->dimTaint as $k => $dimTaint ) { |
| 728 | $pairs = array_merge( |
| 729 | $pairs, |
| 730 | $dimTaint->decomposeForLinks( $links->getForDim( $k ) ) |
| 731 | ); |
| 732 | } |
| 733 | |
| 734 | if ( $this->unknownDimsTaint ) { |
| 735 | $pairs = array_merge( |
| 736 | $pairs, |
| 737 | $this->unknownDimsTaint->decomposeForLinks( $links->getForDim( null ) ) |
| 738 | ); |
| 739 | } |
| 740 | return $pairs; |
| 741 | } |
| 742 | |
| 743 | /** |
| 744 | * Get a stringified representation of this taintedness, useful for debugging etc. |
| 745 | * |
| 746 | * @param string $indent |
| 747 | * @return string |
| 748 | * @suppress PhanUnreferencedPublicMethod |
| 749 | */ |
| 750 | public function toString( $indent = '' ): string { |
| 751 | $flags = SecurityCheckPlugin::taintToString( $this->flags ); |
| 752 | $keys = SecurityCheckPlugin::taintToString( $this->keysTaint ); |
| 753 | $ret = <<<EOT |
| 754 | { |
| 755 | $indent Own taint: $flags |
| 756 | $indent Keys: $keys |
| 757 | $indent Elements: { |
| 758 | EOT; |
| 759 | |
| 760 | $kIndent = "$indent "; |
| 761 | $first = "\n"; |
| 762 | $last = ''; |
| 763 | foreach ( $this->dimTaint as $key => $taint ) { |
| 764 | $ret .= "$first$kIndent $key => " . $taint->toString( "$kIndent " ) . "\n"; |
| 765 | $first = ''; |
| 766 | $last = $kIndent; |
| 767 | } |
| 768 | if ( $this->unknownDimsTaint ) { |
| 769 | $ret .= "$first$kIndent UNKNOWN => " . $this->unknownDimsTaint->toString( "$kIndent " ) . "\n"; |
| 770 | $last = $kIndent; |
| 771 | } |
| 772 | $ret .= "$last}\n$indent}"; |
| 773 | return $ret; |
| 774 | } |
| 775 | |
| 776 | /** |
| 777 | * Get a stringified representation of this taintedness suitable for the debug annotation |
| 778 | * |
| 779 | * @return string |
| 780 | */ |
| 781 | public function toShortString(): string { |
| 782 | $flags = SecurityCheckPlugin::taintToString( $this->flags ); |
| 783 | $ret = "{Own: $flags"; |
| 784 | if ( $this->keysTaint ) { |
| 785 | $ret .= '; Keys: ' . SecurityCheckPlugin::taintToString( $this->keysTaint ); |
| 786 | } |
| 787 | $keyParts = []; |
| 788 | if ( $this->dimTaint ) { |
| 789 | foreach ( $this->dimTaint as $key => $taint ) { |
| 790 | $keyParts[] = "$key => " . $taint->toShortString(); |
| 791 | } |
| 792 | } |
| 793 | if ( $this->unknownDimsTaint ) { |
| 794 | $keyParts[] = 'UNKNOWN => ' . $this->unknownDimsTaint->toShortString(); |
| 795 | } |
| 796 | if ( $keyParts ) { |
| 797 | $ret .= '; Elements: {' . implode( '; ', $keyParts ) . '}'; |
| 798 | } |
| 799 | $ret .= '}'; |
| 800 | return $ret; |
| 801 | } |
| 802 | |
| 803 | /** |
| 804 | * Make sure to clone member variables, too. |
| 805 | */ |
| 806 | public function __clone() { |
| 807 | if ( $this->unknownDimsTaint ) { |
| 808 | $this->unknownDimsTaint = clone $this->unknownDimsTaint; |
| 809 | } |
| 810 | foreach ( $this->dimTaint as $k => $v ) { |
| 811 | $this->dimTaint[$k] = clone $v; |
| 812 | } |
| 813 | } |
| 814 | |
| 815 | /** |
| 816 | * @return string |
| 817 | */ |
| 818 | public function __toString(): string { |
| 819 | return $this->toShortString(); |
| 820 | } |
| 821 | } |