1// SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause 2/* 3 * LZ4 - Fast LZ compression algorithm 4 * Copyright (C) 2011 - 2016, Yann Collet. 5 * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php) 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are 8 * met: 9 * * Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * * Redistributions in binary form must reproduce the above 12 * copyright notice, this list of conditions and the following disclaimer 13 * in the documentation and/or other materials provided with the 14 * distribution. 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * You can contact the author at : 27 * - LZ4 homepage : http://www.lz4.org 28 * - LZ4 source repository : https://github.com/lz4/lz4 29 */ 30#include <compiler.h> 31#include <linux/kernel.h> 32#include <linux/types.h> 33#include <linux/bug.h> 34#include <asm/unaligned.h> 35#include <u-boot/lz4.h> 36 37#define FORCE_INLINE inline __attribute__((always_inline)) 38 39static FORCE_INLINE u16 LZ4_readLE16(const void *src) 40{ 41 return get_unaligned_le16(src); 42} 43 44static FORCE_INLINE void LZ4_copy8(void *dst, const void *src) 45{ 46 put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst); 47} 48 49typedef uint8_t BYTE; 50typedef uint16_t U16; 51typedef uint32_t U32; 52typedef int32_t S32; 53typedef uint64_t U64; 54typedef uintptr_t uptrval; 55 56static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value) 57{ 58 put_unaligned(value, (U32 *)memPtr); 59} 60 61/************************************** 62* Reading and writing into memory 63**************************************/ 64 65/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */ 66static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd) 67{ 68 BYTE* d = (BYTE*)dstPtr; 69 const BYTE* s = (const BYTE*)srcPtr; 70 BYTE* e = (BYTE*)dstEnd; 71 do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e); 72} 73 74 75/************************************** 76* Common Constants 77**************************************/ 78#define MINMATCH 4 79 80#define WILDCOPYLENGTH 8 81#define LASTLITERALS 5 82#define MFLIMIT (WILDCOPYLENGTH + MINMATCH) 83 84/* 85 * ensure it's possible to write 2 x wildcopyLength 86 * without overflowing output buffer 87 */ 88#define MATCH_SAFEGUARD_DISTANCE ((2 * WILDCOPYLENGTH) - MINMATCH) 89 90#define KB (1 <<10) 91 92#define MAXD_LOG 16 93#define MAX_DISTANCE ((1 << MAXD_LOG) - 1) 94 95#define ML_BITS 4 96#define ML_MASK ((1U<<ML_BITS)-1) 97#define RUN_BITS (8-ML_BITS) 98#define RUN_MASK ((1U<<RUN_BITS)-1) 99 100#define LZ4_STATIC_ASSERT(c) BUILD_BUG_ON(!(c)) 101 102/************************************** 103* Local Structures and types 104**************************************/ 105typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive; 106typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; 107typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive; 108 109#define DEBUGLOG(l, ...) {} /* disabled */ 110 111#ifndef assert 112#define assert(condition) ((void)0) 113#endif 114 115/* 116 * LZ4_decompress_generic() : 117 * This generic decompression function covers all use cases. 118 * It shall be instantiated several times, using different sets of directives. 119 * Note that it is important for performance that this function really get inlined, 120 * in order to remove useless branches during compilation optimization. 121 */ 122static FORCE_INLINE int LZ4_decompress_generic( 123 const char * const src, 124 char * const dst, 125 int srcSize, 126 /* 127 * If endOnInput == endOnInputSize, 128 * this value is `dstCapacity` 129 */ 130 int outputSize, 131 /* endOnOutputSize, endOnInputSize */ 132 endCondition_directive endOnInput, 133 /* full, partial */ 134 earlyEnd_directive partialDecoding, 135 /* noDict, withPrefix64k, usingExtDict */ 136 dict_directive dict, 137 /* always <= dst, == dst when no prefix */ 138 const BYTE * const lowPrefix, 139 /* only if dict == usingExtDict */ 140 const BYTE * const dictStart, 141 /* note : = 0 if noDict */ 142 const size_t dictSize 143 ) 144{ 145 const BYTE *ip = (const BYTE *) src; 146 const BYTE * const iend = ip + srcSize; 147 148 BYTE *op = (BYTE *) dst; 149 BYTE * const oend = op + outputSize; 150 BYTE *cpy; 151 152 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize; 153 static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4}; 154 static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3}; 155 156 const int safeDecode = (endOnInput == endOnInputSize); 157 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB))); 158 159 /* Set up the "end" pointers for the shortcut. */ 160 const BYTE *const shortiend = iend - 161 (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; 162 const BYTE *const shortoend = oend - 163 (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; 164 165 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__, 166 srcSize, outputSize); 167 168 /* Special cases */ 169 assert(lowPrefix <= op); 170 assert(src != NULL); 171 172 /* Empty output buffer */ 173 if ((endOnInput) && (unlikely(outputSize == 0))) 174 return ((srcSize == 1) && (*ip == 0)) ? 0 : -1; 175 176 if ((!endOnInput) && (unlikely(outputSize == 0))) 177 return (*ip == 0 ? 1 : -1); 178 179 if ((endOnInput) && unlikely(srcSize == 0)) 180 return -1; 181 182 /* Main Loop : decode sequences */ 183 while (1) { 184 size_t length; 185 const BYTE *match; 186 size_t offset; 187 188 /* get literal length */ 189 unsigned int const token = *ip++; 190 length = token>>ML_BITS; 191 192 /* ip < iend before the increment */ 193 assert(!endOnInput || ip <= iend); 194 195 /* 196 * A two-stage shortcut for the most common case: 197 * 1) If the literal length is 0..14, and there is enough 198 * space, enter the shortcut and copy 16 bytes on behalf 199 * of the literals (in the fast mode, only 8 bytes can be 200 * safely copied this way). 201 * 2) Further if the match length is 4..18, copy 18 bytes 202 * in a similar manner; but we ensure that there's enough 203 * space in the output for those 18 bytes earlier, upon 204 * entering the shortcut (in other words, there is a 205 * combined check for both stages). 206 * 207 * The & in the likely() below is intentionally not && so that 208 * some compilers can produce better parallelized runtime code 209 */ 210 if ((endOnInput ? length != RUN_MASK : length <= 8) 211 /* 212 * strictly "less than" on input, to re-enter 213 * the loop with at least one byte 214 */ 215 && likely((endOnInput ? ip < shortiend : 1) & 216 (op <= shortoend))) { 217 /* Copy the literals */ 218 memcpy(op, ip, endOnInput ? 16 : 8); 219 op += length; ip += length; 220 221 /* 222 * The second stage: 223 * prepare for match copying, decode full info. 224 * If it doesn't work out, the info won't be wasted. 225 */ 226 length = token & ML_MASK; /* match length */ 227 offset = LZ4_readLE16(ip); 228 ip += 2; 229 match = op - offset; 230 assert(match <= op); /* check overflow */ 231 232 /* Do not deal with overlapping matches. */ 233 if ((length != ML_MASK) && 234 (offset >= 8) && 235 (dict == withPrefix64k || match >= lowPrefix)) { 236 /* Copy the match. */ 237 memcpy(op + 0, match + 0, 8); 238 memcpy(op + 8, match + 8, 8); 239 memcpy(op + 16, match + 16, 2); 240 op += length + MINMATCH; 241 /* Both stages worked, load the next token. */ 242 continue; 243 } 244 245 /* 246 * The second stage didn't work out, but the info 247 * is ready. Propel it right to the point of match 248 * copying. 249 */ 250 goto _copy_match; 251 } 252 253 /* decode literal length */ 254 if (length == RUN_MASK) { 255 unsigned int s; 256 257 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) { 258 /* overflow detection */ 259 goto _output_error; 260 } 261 do { 262 s = *ip++; 263 length += s; 264 } while (likely(endOnInput 265 ? ip < iend - RUN_MASK 266 : 1) & (s == 255)); 267 268 if ((safeDecode) 269 && unlikely((uptrval)(op) + 270 length < (uptrval)(op))) { 271 /* overflow detection */ 272 goto _output_error; 273 } 274 if ((safeDecode) 275 && unlikely((uptrval)(ip) + 276 length < (uptrval)(ip))) { 277 /* overflow detection */ 278 goto _output_error; 279 } 280 } 281 282 /* copy literals */ 283 cpy = op + length; 284 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); 285 286 if (((endOnInput) && ((cpy > oend - MFLIMIT) 287 || (ip + length > iend - (2 + 1 + LASTLITERALS)))) 288 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) { 289 if (partialDecoding) { 290 if (cpy > oend) { 291 /* 292 * Partial decoding : 293 * stop in the middle of literal segment 294 */ 295 cpy = oend; 296 length = oend - op; 297 } 298 if ((endOnInput) 299 && (ip + length > iend)) { 300 /* 301 * Error : 302 * read attempt beyond 303 * end of input buffer 304 */ 305 goto _output_error; 306 } 307 } else { 308 if ((!endOnInput) 309 && (cpy != oend)) { 310 /* 311 * Error : 312 * block decoding must 313 * stop exactly there 314 */ 315 goto _output_error; 316 } 317 if ((endOnInput) 318 && ((ip + length != iend) 319 || (cpy > oend))) { 320 /* 321 * Error : 322 * input must be consumed 323 */ 324 goto _output_error; 325 } 326 } 327 328 /* 329 * supports overlapping memory regions; only matters 330 * for in-place decompression scenarios 331 */ 332 memmove(op, ip, length); 333 ip += length; 334 op += length; 335 336 /* Necessarily EOF, due to parsing restrictions */ 337 if (!partialDecoding || (cpy == oend)) 338 break; 339 } else { 340 /* may overwrite up to WILDCOPYLENGTH beyond cpy */ 341 LZ4_wildCopy(op, ip, cpy); 342 ip += length; 343 op = cpy; 344 } 345 346 /* get offset */ 347 offset = LZ4_readLE16(ip); 348 ip += 2; 349 match = op - offset; 350 351 /* get matchlength */ 352 length = token & ML_MASK; 353 354_copy_match: 355 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { 356 /* Error : offset outside buffers */ 357 goto _output_error; 358 } 359 360 /* costs ~1%; silence an msan warning when offset == 0 */ 361 /* 362 * note : when partialDecoding, there is no guarantee that 363 * at least 4 bytes remain available in output buffer 364 */ 365 if (!partialDecoding) { 366 assert(oend > op); 367 assert(oend - op >= 4); 368 369 LZ4_write32(op, (U32)offset); 370 } 371 372 if (length == ML_MASK) { 373 unsigned int s; 374 375 do { 376 s = *ip++; 377 378 if ((endOnInput) && (ip > iend - LASTLITERALS)) 379 goto _output_error; 380 381 length += s; 382 } while (s == 255); 383 384 if ((safeDecode) 385 && unlikely( 386 (uptrval)(op) + length < (uptrval)op)) { 387 /* overflow detection */ 388 goto _output_error; 389 } 390 } 391 392 length += MINMATCH; 393 394 /* match starting within external dictionary */ 395 if ((dict == usingExtDict) && (match < lowPrefix)) { 396 if (unlikely(op + length > oend - LASTLITERALS)) { 397 /* doesn't respect parsing restriction */ 398 if (!partialDecoding) 399 goto _output_error; 400 length = min(length, (size_t)(oend - op)); 401 } 402 403 if (length <= (size_t)(lowPrefix - match)) { 404 /* 405 * match fits entirely within external 406 * dictionary : just copy 407 */ 408 memmove(op, dictEnd - (lowPrefix - match), 409 length); 410 op += length; 411 } else { 412 /* 413 * match stretches into both external 414 * dictionary and current block 415 */ 416 size_t const copySize = (size_t)(lowPrefix - match); 417 size_t const restSize = length - copySize; 418 419 memcpy(op, dictEnd - copySize, copySize); 420 op += copySize; 421 if (restSize > (size_t)(op - lowPrefix)) { 422 /* overlap copy */ 423 BYTE * const endOfMatch = op + restSize; 424 const BYTE *copyFrom = lowPrefix; 425 426 while (op < endOfMatch) 427 *op++ = *copyFrom++; 428 } else { 429 memcpy(op, lowPrefix, restSize); 430 op += restSize; 431 } 432 } 433 continue; 434 } 435 436 /* copy match within block */ 437 cpy = op + length; 438 439 /* 440 * partialDecoding : 441 * may not respect endBlock parsing restrictions 442 */ 443 assert(op <= oend); 444 if (partialDecoding && 445 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 446 size_t const mlen = min(length, (size_t)(oend - op)); 447 const BYTE * const matchEnd = match + mlen; 448 BYTE * const copyEnd = op + mlen; 449 450 if (matchEnd > op) { 451 /* overlap copy */ 452 while (op < copyEnd) 453 *op++ = *match++; 454 } else { 455 memcpy(op, match, mlen); 456 } 457 op = copyEnd; 458 if (op == oend) 459 break; 460 continue; 461 } 462 463 if (unlikely(offset < 8)) { 464 op[0] = match[0]; 465 op[1] = match[1]; 466 op[2] = match[2]; 467 op[3] = match[3]; 468 match += inc32table[offset]; 469 memcpy(op + 4, match, 4); 470 match -= dec64table[offset]; 471 } else { 472 LZ4_copy8(op, match); 473 match += 8; 474 } 475 476 op += 8; 477 478 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 479 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1); 480 481 if (cpy > oend - LASTLITERALS) { 482 /* 483 * Error : last LASTLITERALS bytes 484 * must be literals (uncompressed) 485 */ 486 goto _output_error; 487 } 488 489 if (op < oCopyLimit) { 490 LZ4_wildCopy(op, match, oCopyLimit); 491 match += oCopyLimit - op; 492 op = oCopyLimit; 493 } 494 while (op < cpy) 495 *op++ = *match++; 496 } else { 497 LZ4_copy8(op, match); 498 if (length > 16) 499 LZ4_wildCopy(op + 8, match + 8, cpy); 500 } 501 op = cpy; /* wildcopy correction */ 502 } 503 504 /* end of decoding */ 505 if (endOnInput) { 506 /* Nb of output bytes decoded */ 507 return (int) (((char *)op) - dst); 508 } else { 509 /* Nb of input bytes read */ 510 return (int) (((const char *)ip) - src); 511 } 512 513 /* Overflow error detected */ 514_output_error: 515 return (int) (-(((const char *)ip) - src)) - 1; 516} 517 518int LZ4_decompress_safe(const char *source, char *dest, 519 int compressedSize, int maxDecompressedSize) 520{ 521 return LZ4_decompress_generic(source, dest, 522 compressedSize, maxDecompressedSize, 523 endOnInputSize, decode_full_block, 524 noDict, (BYTE *)dest, NULL, 0); 525} 526 527int LZ4_decompress_safe_partial(const char *src, char *dst, 528 int compressedSize, int targetOutputSize, int dstCapacity) 529{ 530 dstCapacity = min(targetOutputSize, dstCapacity); 531 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, 532 endOnInputSize, partial_decode, 533 noDict, (BYTE *)dst, NULL, 0); 534} 535