/* * LZ4 Decompressor for Linux kernel * * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com> * * Based on LZ4 implementation by Yann Collet. * * LZ4 - Fast LZ compression algorithm * Copyright (C) 2011-2012, 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://fastcompression.blogspot.com/p/lz4.html * - LZ4 source repository : http://code.google.com/p/lz4/ */ #ifndef STATIC #include <linux/module.h> #include <linux/kernel.h> #endif #include <linux/lz4.h> #include <asm/unaligned.h> #include "lz4defs.h" static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; #if LZ4_ARCH64 static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; #endif static int lz4_uncompress(const char *source, char *dest, int osize) { const BYTE *ip = (const BYTE *) source; const BYTE *ref; BYTE *op = (BYTE *) dest; BYTE * const oend = op + osize; BYTE *cpy; unsigned token; size_t length; while (1) { /* get runlength */ token = *ip++; length = (token >> ML_BITS); if (length == RUN_MASK) { size_t len; len = *ip++; for (; len == 255; length += 255) len = *ip++; if (unlikely(length > (size_t)(length + len))) goto _output_error; length += len; } /* copy literals */ cpy = op + length; if (unlikely(cpy > oend - COPYLENGTH)) { /* * Error: not enough place for another match * (min 4) + 5 literals */ if (cpy != oend) goto _output_error; memcpy(op, ip, length); ip += length; break; /* EOF */ } LZ4_WILDCOPY(ip, op, cpy); ip -= (op - cpy); op = cpy; /* get offset */ LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); ip += 2; /* Error: offset create reference outside destination buffer */ if (unlikely(ref < (BYTE *const) dest)) goto _output_error; /* get matchlength */ length = token & ML_MASK; if (length == ML_MASK) { for (; *ip == 255; length += 255) ip++; if (unlikely(length > (size_t)(length + *ip))) goto _output_error; length += *ip++; } /* copy repeated sequence */ if (unlikely((op - ref) < STEPSIZE)) { #if LZ4_ARCH64 int dec64 = dec64table[op - ref]; #else const int dec64 = 0; #endif op[0] = ref[0]; op[1] = ref[1]; op[2] = ref[2]; op[3] = ref[3]; op += 4; ref += 4; ref -= dec32table[op-ref]; PUT4(ref, op); op += STEPSIZE - 4; ref -= dec64; } else { LZ4_COPYSTEP(ref, op); } cpy = op + length - (STEPSIZE - 4); if (cpy > (oend - COPYLENGTH)) { /* Error: request to write beyond destination buffer */ if (cpy > oend) goto _output_error; #if LZ4_ARCH64 if ((ref + COPYLENGTH) > oend) #else if ((ref + COPYLENGTH) > oend || (op + COPYLENGTH) > oend) #endif goto _output_error; LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); while (op < cpy) *op++ = *ref++; op = cpy; /* * Check EOF (should never happen, since last 5 bytes * are supposed to be literals) */ if (op == oend) goto _output_error; continue; } LZ4_SECURECOPY(ref, op, cpy); op = cpy; /* correction */ } /* end of decoding */ return (int) (((char *)ip) - source); /* write overflow error detected */ _output_error: return -1; } static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, int isize, size_t maxoutputsize) { const BYTE *ip = (const BYTE *) source; const BYTE *const iend = ip + isize; const BYTE *ref; BYTE *op = (BYTE *) dest; BYTE * const oend = op + maxoutputsize; BYTE *cpy; /* Main Loop */ while (ip < iend) { unsigned token; size_t length; /* get runlength */ token = *ip++; length = (token >> ML_BITS); if (length == RUN_MASK) { int s = 255; while ((ip < iend) && (s == 255)) { s = *ip++; if (unlikely(length > (size_t)(length + s))) goto _output_error; length += s; } } /* copy literals */ cpy = op + length; if ((cpy > oend - COPYLENGTH) || (ip + length > iend - COPYLENGTH)) { if (cpy > oend) goto _output_error;/* writes beyond buffer */ if (ip + length != iend) goto _output_error;/* * Error: LZ4 format requires * to consume all input * at this stage */ memcpy(op, ip, length); op += length; break;/* Necessarily EOF, due to parsing restrictions */ } LZ4_WILDCOPY(ip, op, cpy); ip -= (op - cpy); op = cpy; /* get offset */ LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); ip += 2; if (ref < (BYTE * const) dest) goto _output_error; /* * Error : offset creates reference * outside of destination buffer */ /* get matchlength */ length = (token & ML_MASK); if (length == ML_MASK) { while (ip < iend) { int s = *ip++; if (unlikely(length > (size_t)(length + s))) goto _output_error; length += s; if (s == 255) continue; break; } } /* copy repeated sequence */ if (unlikely((op - ref) < STEPSIZE)) { #if LZ4_ARCH64 int dec64 = dec64table[op - ref]; #else const int dec64 = 0; #endif op[0] = ref[0]; op[1] = ref[1]; op[2] = ref[2]; op[3] = ref[3]; op += 4; ref += 4; ref -= dec32table[op - ref]; PUT4(ref, op); op += STEPSIZE - 4; ref -= dec64; } else { LZ4_COPYSTEP(ref, op); } cpy = op + length - (STEPSIZE-4); if (cpy > oend - COPYLENGTH) { if (cpy > oend) goto _output_error; /* write outside of buf */ #if LZ4_ARCH64 if ((ref + COPYLENGTH) > oend) #else if ((ref + COPYLENGTH) > oend || (op + COPYLENGTH) > oend) #endif goto _output_error; LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); while (op < cpy) *op++ = *ref++; op = cpy; /* * Check EOF (should never happen, since last 5 bytes * are supposed to be literals) */ if (op == oend) goto _output_error; continue; } LZ4_SECURECOPY(ref, op, cpy); op = cpy; /* correction */ } /* end of decoding */ return (int) (((char *) op) - dest); /* write overflow error detected */ _output_error: return -1; } int lz4_decompress(const unsigned char *src, size_t *src_len, unsigned char *dest, size_t actual_dest_len) { int ret = -1; int input_len = 0; input_len = lz4_uncompress(src, dest, actual_dest_len); if (input_len < 0) goto exit_0; *src_len = input_len; return 0; exit_0: return ret; } #ifndef STATIC EXPORT_SYMBOL(lz4_decompress); #endif int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len, unsigned char *dest, size_t *dest_len) { int ret = -1; int out_len = 0; out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, *dest_len); if (out_len < 0) goto exit_0; *dest_len = out_len; return 0; exit_0: return ret; } #ifndef STATIC EXPORT_SYMBOL(lz4_decompress_unknownoutputsize); MODULE_LICENSE("Dual BSD/GPL"); MODULE_DESCRIPTION("LZ4 Decompressor"); #endif