From: Huang Jianan huangjianan@oppo.com
In order to use the newest LZ4_decompress_safe_partial() which can now decode exactly the nb of bytes requested.
Signed-off-by: Huang Jianan jnhuang95@gmail.com --- fs/erofs/Makefile | 3 +- fs/erofs/lz4.c | 534 ++++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/lz4.h | 4 + 3 files changed, 540 insertions(+), 1 deletion(-) create mode 100644 fs/erofs/lz4.c create mode 100644 fs/erofs/lz4.h
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile index 7398ab7a36..c4fc5b794e 100644 --- a/fs/erofs/Makefile +++ b/fs/erofs/Makefile @@ -4,4 +4,5 @@ obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \ super.o \ namei.o \ - data.o + data.o \ + lz4.o diff --git a/fs/erofs/lz4.c b/fs/erofs/lz4.c new file mode 100644 index 0000000000..35f67c15eb --- /dev/null +++ b/fs/erofs/lz4.c @@ -0,0 +1,534 @@ +// SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause +/* + * LZ4 - Fast LZ compression algorithm + * Copyright (C) 2011 - 2016, Yann Collet. + * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php) + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * You can contact the author at : + * - LZ4 homepage : http://www.lz4.org + * - LZ4 source repository : https://github.com/lz4/lz4 + */ +#include <common.h> +#include <compiler.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/bug.h> +#include <asm/unaligned.h> + +#define FORCE_INLINE inline __attribute__((always_inline)) + +static FORCE_INLINE u16 LZ4_readLE16(const void *src) +{ + return get_unaligned_le16(src); +} + +static FORCE_INLINE void LZ4_copy8(void *dst, const void *src) +{ + put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst); +} + +typedef uint8_t BYTE; +typedef uint16_t U16; +typedef uint32_t U32; +typedef int32_t S32; +typedef uint64_t U64; +typedef uintptr_t uptrval; + +static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value) +{ + put_unaligned(value, (U32 *)memPtr); +} + +/************************************** +* Reading and writing into memory +**************************************/ + +/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */ +static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd) +{ + BYTE* d = (BYTE*)dstPtr; + const BYTE* s = (const BYTE*)srcPtr; + BYTE* e = (BYTE*)dstEnd; + do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e); +} + + +/************************************** +* Common Constants +**************************************/ +#define MINMATCH 4 + +#define WILDCOPYLENGTH 8 +#define LASTLITERALS 5 +#define MFLIMIT (WILDCOPYLENGTH + MINMATCH) + +/* + * ensure it's possible to write 2 x wildcopyLength + * without overflowing output buffer + */ +#define MATCH_SAFEGUARD_DISTANCE ((2 * WILDCOPYLENGTH) - MINMATCH) + +#define KB (1 <<10) + +#define MAXD_LOG 16 +#define MAX_DISTANCE ((1 << MAXD_LOG) - 1) + +#define ML_BITS 4 +#define ML_MASK ((1U<<ML_BITS)-1) +#define RUN_BITS (8-ML_BITS) +#define RUN_MASK ((1U<<RUN_BITS)-1) + +#define LZ4_STATIC_ASSERT(c) BUILD_BUG_ON(!(c)) + +/************************************** +* Local Structures and types +**************************************/ +typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive; +typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; +typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive; + +#define DEBUGLOG(l, ...) {} /* disabled */ + +#ifndef assert +#define assert(condition) ((void)0) +#endif + +/* + * LZ4_decompress_generic() : + * This generic decompression function covers all use cases. + * It shall be instantiated several times, using different sets of directives. + * Note that it is important for performance that this function really get inlined, + * in order to remove useless branches during compilation optimization. + */ +static FORCE_INLINE int LZ4_decompress_generic( + const char * const src, + char * const dst, + int srcSize, + /* + * If endOnInput == endOnInputSize, + * this value is `dstCapacity` + */ + int outputSize, + /* endOnOutputSize, endOnInputSize */ + endCondition_directive endOnInput, + /* full, partial */ + earlyEnd_directive partialDecoding, + /* noDict, withPrefix64k, usingExtDict */ + dict_directive dict, + /* always <= dst, == dst when no prefix */ + const BYTE * const lowPrefix, + /* only if dict == usingExtDict */ + const BYTE * const dictStart, + /* note : = 0 if noDict */ + const size_t dictSize + ) +{ + const BYTE *ip = (const BYTE *) src; + const BYTE * const iend = ip + srcSize; + + BYTE *op = (BYTE *) dst; + BYTE * const oend = op + outputSize; + BYTE *cpy; + + const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize; + static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4}; + static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3}; + + const int safeDecode = (endOnInput == endOnInputSize); + const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB))); + + /* Set up the "end" pointers for the shortcut. */ + const BYTE *const shortiend = iend - + (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; + const BYTE *const shortoend = oend - + (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; + + DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__, + srcSize, outputSize); + + /* Special cases */ + assert(lowPrefix <= op); + assert(src != NULL); + + /* Empty output buffer */ + if ((endOnInput) && (unlikely(outputSize == 0))) + return ((srcSize == 1) && (*ip == 0)) ? 0 : -1; + + if ((!endOnInput) && (unlikely(outputSize == 0))) + return (*ip == 0 ? 1 : -1); + + if ((endOnInput) && unlikely(srcSize == 0)) + return -1; + + /* Main Loop : decode sequences */ + while (1) { + size_t length; + const BYTE *match; + size_t offset; + + /* get literal length */ + unsigned int const token = *ip++; + length = token>>ML_BITS; + + /* ip < iend before the increment */ + assert(!endOnInput || ip <= iend); + + /* + * A two-stage shortcut for the most common case: + * 1) If the literal length is 0..14, and there is enough + * space, enter the shortcut and copy 16 bytes on behalf + * of the literals (in the fast mode, only 8 bytes can be + * safely copied this way). + * 2) Further if the match length is 4..18, copy 18 bytes + * in a similar manner; but we ensure that there's enough + * space in the output for those 18 bytes earlier, upon + * entering the shortcut (in other words, there is a + * combined check for both stages). + * + * The & in the likely() below is intentionally not && so that + * some compilers can produce better parallelized runtime code + */ + if ((endOnInput ? length != RUN_MASK : length <= 8) + /* + * strictly "less than" on input, to re-enter + * the loop with at least one byte + */ + && likely((endOnInput ? ip < shortiend : 1) & + (op <= shortoend))) { + /* Copy the literals */ + memcpy(op, ip, endOnInput ? 16 : 8); + op += length; ip += length; + + /* + * The second stage: + * prepare for match copying, decode full info. + * If it doesn't work out, the info won't be wasted. + */ + length = token & ML_MASK; /* match length */ + offset = LZ4_readLE16(ip); + ip += 2; + match = op - offset; + assert(match <= op); /* check overflow */ + + /* Do not deal with overlapping matches. */ + if ((length != ML_MASK) && + (offset >= 8) && + (dict == withPrefix64k || match >= lowPrefix)) { + /* Copy the match. */ + memcpy(op + 0, match + 0, 8); + memcpy(op + 8, match + 8, 8); + memcpy(op + 16, match + 16, 2); + op += length + MINMATCH; + /* Both stages worked, load the next token. */ + continue; + } + + /* + * The second stage didn't work out, but the info + * is ready. Propel it right to the point of match + * copying. + */ + goto _copy_match; + } + + /* decode literal length */ + if (length == RUN_MASK) { + unsigned int s; + + if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) { + /* overflow detection */ + goto _output_error; + } + do { + s = *ip++; + length += s; + } while (likely(endOnInput + ? ip < iend - RUN_MASK + : 1) & (s == 255)); + + if ((safeDecode) + && unlikely((uptrval)(op) + + length < (uptrval)(op))) { + /* overflow detection */ + goto _output_error; + } + if ((safeDecode) + && unlikely((uptrval)(ip) + + length < (uptrval)(ip))) { + /* overflow detection */ + goto _output_error; + } + } + + /* copy literals */ + cpy = op + length; + LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); + + if (((endOnInput) && ((cpy > oend - MFLIMIT) + || (ip + length > iend - (2 + 1 + LASTLITERALS)))) + || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) { + if (partialDecoding) { + if (cpy > oend) { + /* + * Partial decoding : + * stop in the middle of literal segment + */ + cpy = oend; + length = oend - op; + } + if ((endOnInput) + && (ip + length > iend)) { + /* + * Error : + * read attempt beyond + * end of input buffer + */ + goto _output_error; + } + } else { + if ((!endOnInput) + && (cpy != oend)) { + /* + * Error : + * block decoding must + * stop exactly there + */ + goto _output_error; + } + if ((endOnInput) + && ((ip + length != iend) + || (cpy > oend))) { + /* + * Error : + * input must be consumed + */ + goto _output_error; + } + } + + /* + * supports overlapping memory regions; only matters + * for in-place decompression scenarios + */ + memmove(op, ip, length); + ip += length; + op += length; + + /* Necessarily EOF, due to parsing restrictions */ + if (!partialDecoding || (cpy == oend)) + break; + } else { + /* may overwrite up to WILDCOPYLENGTH beyond cpy */ + LZ4_wildCopy(op, ip, cpy); + ip += length; + op = cpy; + } + + /* get offset */ + offset = LZ4_readLE16(ip); + ip += 2; + match = op - offset; + + /* get matchlength */ + length = token & ML_MASK; + +_copy_match: + if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { + /* Error : offset outside buffers */ + goto _output_error; + } + + /* costs ~1%; silence an msan warning when offset == 0 */ + /* + * note : when partialDecoding, there is no guarantee that + * at least 4 bytes remain available in output buffer + */ + if (!partialDecoding) { + assert(oend > op); + assert(oend - op >= 4); + + LZ4_write32(op, (U32)offset); + } + + if (length == ML_MASK) { + unsigned int s; + + do { + s = *ip++; + + if ((endOnInput) && (ip > iend - LASTLITERALS)) + goto _output_error; + + length += s; + } while (s == 255); + + if ((safeDecode) + && unlikely( + (uptrval)(op) + length < (uptrval)op)) { + /* overflow detection */ + goto _output_error; + } + } + + length += MINMATCH; + + /* match starting within external dictionary */ + if ((dict == usingExtDict) && (match < lowPrefix)) { + if (unlikely(op + length > oend - LASTLITERALS)) { + /* doesn't respect parsing restriction */ + if (!partialDecoding) + goto _output_error; + length = min(length, (size_t)(oend - op)); + } + + if (length <= (size_t)(lowPrefix - match)) { + /* + * match fits entirely within external + * dictionary : just copy + */ + memmove(op, dictEnd - (lowPrefix - match), + length); + op += length; + } else { + /* + * match stretches into both external + * dictionary and current block + */ + size_t const copySize = (size_t)(lowPrefix - match); + size_t const restSize = length - copySize; + + memcpy(op, dictEnd - copySize, copySize); + op += copySize; + if (restSize > (size_t)(op - lowPrefix)) { + /* overlap copy */ + BYTE * const endOfMatch = op + restSize; + const BYTE *copyFrom = lowPrefix; + + while (op < endOfMatch) + *op++ = *copyFrom++; + } else { + memcpy(op, lowPrefix, restSize); + op += restSize; + } + } + continue; + } + + /* copy match within block */ + cpy = op + length; + + /* + * partialDecoding : + * may not respect endBlock parsing restrictions + */ + assert(op <= oend); + if (partialDecoding && + (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { + size_t const mlen = min(length, (size_t)(oend - op)); + const BYTE * const matchEnd = match + mlen; + BYTE * const copyEnd = op + mlen; + + if (matchEnd > op) { + /* overlap copy */ + while (op < copyEnd) + *op++ = *match++; + } else { + memcpy(op, match, mlen); + } + op = copyEnd; + if (op == oend) + break; + continue; + } + + if (unlikely(offset < 8)) { + op[0] = match[0]; + op[1] = match[1]; + op[2] = match[2]; + op[3] = match[3]; + match += inc32table[offset]; + memcpy(op + 4, match, 4); + match -= dec64table[offset]; + } else { + LZ4_copy8(op, match); + match += 8; + } + + op += 8; + + if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { + BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1); + + if (cpy > oend - LASTLITERALS) { + /* + * Error : last LASTLITERALS bytes + * must be literals (uncompressed) + */ + goto _output_error; + } + + if (op < oCopyLimit) { + LZ4_wildCopy(op, match, oCopyLimit); + match += oCopyLimit - op; + op = oCopyLimit; + } + while (op < cpy) + *op++ = *match++; + } else { + LZ4_copy8(op, match); + if (length > 16) + LZ4_wildCopy(op + 8, match + 8, cpy); + } + op = cpy; /* wildcopy correction */ + } + + /* end of decoding */ + if (endOnInput) { + /* Nb of output bytes decoded */ + return (int) (((char *)op) - dst); + } else { + /* Nb of input bytes read */ + return (int) (((const char *)ip) - src); + } + + /* Overflow error detected */ +_output_error: + return (int) (-(((const char *)ip) - src)) - 1; +} + +int LZ4_decompress_safe(const char *source, char *dest, + int compressedSize, int maxDecompressedSize) +{ + return LZ4_decompress_generic(source, dest, + compressedSize, maxDecompressedSize, + endOnInputSize, decode_full_block, + noDict, (BYTE *)dest, NULL, 0); +} + +int LZ4_decompress_safe_partial(const char *src, char *dst, + int compressedSize, int targetOutputSize, int dstCapacity) +{ + dstCapacity = min(targetOutputSize, dstCapacity); + return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, + endOnInputSize, partial_decode, + noDict, (BYTE *)dst, NULL, 0); +} diff --git a/fs/erofs/lz4.h b/fs/erofs/lz4.h new file mode 100644 index 0000000000..0b4bdf4fbe --- /dev/null +++ b/fs/erofs/lz4.h @@ -0,0 +1,4 @@ +int LZ4_decompress_safe(const char *source, char *dest, + int compressedSize, int maxDecompressedSize); +int LZ4_decompress_safe_partial(const char *src, char *dst, + int compressedSize, int targetOutputSize, int dstCapacity);