1 /* 2 * LZ4 Decompressor for Linux kernel 3 * 4 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com> 5 * 6 * Based on LZ4 implementation by Yann Collet. 7 * 8 * LZ4 - Fast LZ compression algorithm 9 * Copyright (C) 2011-2012, Yann Collet. 10 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions are 14 * met: 15 * 16 * * Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * * Redistributions in binary form must reproduce the above 19 * copyright notice, this list of conditions and the following disclaimer 20 * in the documentation and/or other materials provided with the 21 * distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 33 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 * 35 * You can contact the author at : 36 * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html 37 * - LZ4 source repository : http://code.google.com/p/lz4/ 38 */ 39 40 #ifndef STATIC 41 #include <linux/module.h> 42 #include <linux/kernel.h> 43 #endif 44 #include <linux/lz4.h> 45 46 #include <asm/unaligned.h> 47 48 #include "lz4defs.h" 49 50 static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; 51 #if LZ4_ARCH64 52 static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; 53 #endif 54 55 static int lz4_uncompress(const char *source, char *dest, int osize) 56 { 57 const BYTE *ip = (const BYTE *) source; 58 const BYTE *ref; 59 BYTE *op = (BYTE *) dest; 60 BYTE * const oend = op + osize; 61 BYTE *cpy; 62 unsigned token; 63 size_t length; 64 65 while (1) { 66 67 /* get runlength */ 68 token = *ip++; 69 length = (token >> ML_BITS); 70 if (length == RUN_MASK) { 71 size_t len; 72 73 len = *ip++; 74 for (; len == 255; length += 255) 75 len = *ip++; 76 if (unlikely(length > (size_t)(length + len))) 77 goto _output_error; 78 length += len; 79 } 80 81 /* copy literals */ 82 cpy = op + length; 83 if (unlikely(cpy > oend - COPYLENGTH)) { 84 /* 85 * Error: not enough place for another match 86 * (min 4) + 5 literals 87 */ 88 if (cpy != oend) 89 goto _output_error; 90 91 memcpy(op, ip, length); 92 ip += length; 93 break; /* EOF */ 94 } 95 LZ4_WILDCOPY(ip, op, cpy); 96 ip -= (op - cpy); 97 op = cpy; 98 99 /* get offset */ 100 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); 101 ip += 2; 102 103 /* Error: offset create reference outside destination buffer */ 104 if (unlikely(ref < (BYTE *const) dest)) 105 goto _output_error; 106 107 /* get matchlength */ 108 length = token & ML_MASK; 109 if (length == ML_MASK) { 110 for (; *ip == 255; length += 255) 111 ip++; 112 if (unlikely(length > (size_t)(length + *ip))) 113 goto _output_error; 114 length += *ip++; 115 } 116 117 /* copy repeated sequence */ 118 if (unlikely((op - ref) < STEPSIZE)) { 119 #if LZ4_ARCH64 120 int dec64 = dec64table[op - ref]; 121 #else 122 const int dec64 = 0; 123 #endif 124 op[0] = ref[0]; 125 op[1] = ref[1]; 126 op[2] = ref[2]; 127 op[3] = ref[3]; 128 op += 4; 129 ref += 4; 130 ref -= dec32table[op-ref]; 131 PUT4(ref, op); 132 op += STEPSIZE - 4; 133 ref -= dec64; 134 } else { 135 LZ4_COPYSTEP(ref, op); 136 } 137 cpy = op + length - (STEPSIZE - 4); 138 if (cpy > (oend - COPYLENGTH)) { 139 140 /* Error: request to write beyond destination buffer */ 141 if (cpy > oend) 142 goto _output_error; 143 #if LZ4_ARCH64 144 if ((ref + COPYLENGTH) > oend) 145 #else 146 if ((ref + COPYLENGTH) > oend || 147 (op + COPYLENGTH) > oend) 148 #endif 149 goto _output_error; 150 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); 151 while (op < cpy) 152 *op++ = *ref++; 153 op = cpy; 154 /* 155 * Check EOF (should never happen, since last 5 bytes 156 * are supposed to be literals) 157 */ 158 if (op == oend) 159 goto _output_error; 160 continue; 161 } 162 LZ4_SECURECOPY(ref, op, cpy); 163 op = cpy; /* correction */ 164 } 165 /* end of decoding */ 166 return (int) (((char *)ip) - source); 167 168 /* write overflow error detected */ 169 _output_error: 170 return -1; 171 } 172 173 static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, 174 int isize, size_t maxoutputsize) 175 { 176 const BYTE *ip = (const BYTE *) source; 177 const BYTE *const iend = ip + isize; 178 const BYTE *ref; 179 180 181 BYTE *op = (BYTE *) dest; 182 BYTE * const oend = op + maxoutputsize; 183 BYTE *cpy; 184 185 /* Main Loop */ 186 while (ip < iend) { 187 188 unsigned token; 189 size_t length; 190 191 /* get runlength */ 192 token = *ip++; 193 length = (token >> ML_BITS); 194 if (length == RUN_MASK) { 195 int s = 255; 196 while ((ip < iend) && (s == 255)) { 197 s = *ip++; 198 if (unlikely(length > (size_t)(length + s))) 199 goto _output_error; 200 length += s; 201 } 202 } 203 /* copy literals */ 204 cpy = op + length; 205 if ((cpy > oend - COPYLENGTH) || 206 (ip + length > iend - COPYLENGTH)) { 207 208 if (cpy > oend) 209 goto _output_error;/* writes beyond buffer */ 210 211 if (ip + length != iend) 212 goto _output_error;/* 213 * Error: LZ4 format requires 214 * to consume all input 215 * at this stage 216 */ 217 memcpy(op, ip, length); 218 op += length; 219 break;/* Necessarily EOF, due to parsing restrictions */ 220 } 221 LZ4_WILDCOPY(ip, op, cpy); 222 ip -= (op - cpy); 223 op = cpy; 224 225 /* get offset */ 226 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); 227 ip += 2; 228 if (ref < (BYTE * const) dest) 229 goto _output_error; 230 /* 231 * Error : offset creates reference 232 * outside of destination buffer 233 */ 234 235 /* get matchlength */ 236 length = (token & ML_MASK); 237 if (length == ML_MASK) { 238 while (ip < iend) { 239 int s = *ip++; 240 if (unlikely(length > (size_t)(length + s))) 241 goto _output_error; 242 length += s; 243 if (s == 255) 244 continue; 245 break; 246 } 247 } 248 249 /* copy repeated sequence */ 250 if (unlikely((op - ref) < STEPSIZE)) { 251 #if LZ4_ARCH64 252 int dec64 = dec64table[op - ref]; 253 #else 254 const int dec64 = 0; 255 #endif 256 op[0] = ref[0]; 257 op[1] = ref[1]; 258 op[2] = ref[2]; 259 op[3] = ref[3]; 260 op += 4; 261 ref += 4; 262 ref -= dec32table[op - ref]; 263 PUT4(ref, op); 264 op += STEPSIZE - 4; 265 ref -= dec64; 266 } else { 267 LZ4_COPYSTEP(ref, op); 268 } 269 cpy = op + length - (STEPSIZE-4); 270 if (cpy > oend - COPYLENGTH) { 271 if (cpy > oend) 272 goto _output_error; /* write outside of buf */ 273 #if LZ4_ARCH64 274 if ((ref + COPYLENGTH) > oend) 275 #else 276 if ((ref + COPYLENGTH) > oend || 277 (op + COPYLENGTH) > oend) 278 #endif 279 goto _output_error; 280 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); 281 while (op < cpy) 282 *op++ = *ref++; 283 op = cpy; 284 /* 285 * Check EOF (should never happen, since last 5 bytes 286 * are supposed to be literals) 287 */ 288 if (op == oend) 289 goto _output_error; 290 continue; 291 } 292 LZ4_SECURECOPY(ref, op, cpy); 293 op = cpy; /* correction */ 294 } 295 /* end of decoding */ 296 return (int) (((char *) op) - dest); 297 298 /* write overflow error detected */ 299 _output_error: 300 return -1; 301 } 302 303 int lz4_decompress(const unsigned char *src, size_t *src_len, 304 unsigned char *dest, size_t actual_dest_len) 305 { 306 int ret = -1; 307 int input_len = 0; 308 309 input_len = lz4_uncompress(src, dest, actual_dest_len); 310 if (input_len < 0) 311 goto exit_0; 312 *src_len = input_len; 313 314 return 0; 315 exit_0: 316 return ret; 317 } 318 #ifndef STATIC 319 EXPORT_SYMBOL(lz4_decompress); 320 #endif 321 322 int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len, 323 unsigned char *dest, size_t *dest_len) 324 { 325 int ret = -1; 326 int out_len = 0; 327 328 out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, 329 *dest_len); 330 if (out_len < 0) 331 goto exit_0; 332 *dest_len = out_len; 333 334 return 0; 335 exit_0: 336 return ret; 337 } 338 #ifndef STATIC 339 EXPORT_SYMBOL(lz4_decompress_unknownoutputsize); 340 341 MODULE_LICENSE("Dual BSD/GPL"); 342 MODULE_DESCRIPTION("LZ4 Decompressor"); 343 #endif 344