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 int lz4_uncompress(const char *source, char *dest, int osize) 51 { 52 const BYTE *ip = (const BYTE *) source; 53 const BYTE *ref; 54 BYTE *op = (BYTE *) dest; 55 BYTE * const oend = op + osize; 56 BYTE *cpy; 57 unsigned token; 58 size_t length; 59 size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; 60 #if LZ4_ARCH64 61 size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; 62 #endif 63 64 while (1) { 65 66 /* get runlength */ 67 token = *ip++; 68 length = (token >> ML_BITS); 69 if (length == RUN_MASK) { 70 size_t len; 71 72 len = *ip++; 73 for (; len == 255; length += 255) 74 len = *ip++; 75 if (unlikely(length > (size_t)(length + len))) 76 goto _output_error; 77 length += len; 78 } 79 80 /* copy literals */ 81 cpy = op + length; 82 if (unlikely(cpy > oend - COPYLENGTH)) { 83 /* 84 * Error: not enough place for another match 85 * (min 4) + 5 literals 86 */ 87 if (cpy != oend) 88 goto _output_error; 89 90 memcpy(op, ip, length); 91 ip += length; 92 break; /* EOF */ 93 } 94 LZ4_WILDCOPY(ip, op, cpy); 95 ip -= (op - cpy); 96 op = cpy; 97 98 /* get offset */ 99 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); 100 ip += 2; 101 102 /* Error: offset create reference outside destination buffer */ 103 if (unlikely(ref < (BYTE *const) dest)) 104 goto _output_error; 105 106 /* get matchlength */ 107 length = token & ML_MASK; 108 if (length == ML_MASK) { 109 for (; *ip == 255; length += 255) 110 ip++; 111 if (unlikely(length > (size_t)(length + *ip))) 112 goto _output_error; 113 length += *ip++; 114 } 115 116 /* copy repeated sequence */ 117 if (unlikely((op - ref) < STEPSIZE)) { 118 #if LZ4_ARCH64 119 size_t dec64 = dec64table[op - ref]; 120 #else 121 const int dec64 = 0; 122 #endif 123 op[0] = ref[0]; 124 op[1] = ref[1]; 125 op[2] = ref[2]; 126 op[3] = ref[3]; 127 op += 4; 128 ref += 4; 129 ref -= dec32table[op-ref]; 130 PUT4(ref, op); 131 op += STEPSIZE - 4; 132 ref -= dec64; 133 } else { 134 LZ4_COPYSTEP(ref, op); 135 } 136 cpy = op + length - (STEPSIZE - 4); 137 if (cpy > (oend - COPYLENGTH)) { 138 139 /* Error: request to write beyond destination buffer */ 140 if (cpy > oend) 141 goto _output_error; 142 if ((ref + COPYLENGTH) > oend || 143 (op + COPYLENGTH) > oend) 144 goto _output_error; 145 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); 146 while (op < cpy) 147 *op++ = *ref++; 148 op = cpy; 149 /* 150 * Check EOF (should never happen, since last 5 bytes 151 * are supposed to be literals) 152 */ 153 if (op == oend) 154 goto _output_error; 155 continue; 156 } 157 LZ4_SECURECOPY(ref, op, cpy); 158 op = cpy; /* correction */ 159 } 160 /* end of decoding */ 161 return (int) (((char *)ip) - source); 162 163 /* write overflow error detected */ 164 _output_error: 165 return -1; 166 } 167 168 static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, 169 int isize, size_t maxoutputsize) 170 { 171 const BYTE *ip = (const BYTE *) source; 172 const BYTE *const iend = ip + isize; 173 const BYTE *ref; 174 175 176 BYTE *op = (BYTE *) dest; 177 BYTE * const oend = op + maxoutputsize; 178 BYTE *cpy; 179 180 size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; 181 #if LZ4_ARCH64 182 size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; 183 #endif 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 size_t 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 */ 273 274 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); 275 while (op < cpy) 276 *op++ = *ref++; 277 op = cpy; 278 /* 279 * Check EOF (should never happen, since last 5 bytes 280 * are supposed to be literals) 281 */ 282 if (op == oend) 283 goto _output_error; 284 continue; 285 } 286 LZ4_SECURECOPY(ref, op, cpy); 287 op = cpy; /* correction */ 288 } 289 /* end of decoding */ 290 return (int) (((char *) op) - dest); 291 292 /* write overflow error detected */ 293 _output_error: 294 return -1; 295 } 296 297 int lz4_decompress(const unsigned char *src, size_t *src_len, 298 unsigned char *dest, size_t actual_dest_len) 299 { 300 int ret = -1; 301 int input_len = 0; 302 303 input_len = lz4_uncompress(src, dest, actual_dest_len); 304 if (input_len < 0) 305 goto exit_0; 306 *src_len = input_len; 307 308 return 0; 309 exit_0: 310 return ret; 311 } 312 #ifndef STATIC 313 EXPORT_SYMBOL(lz4_decompress); 314 #endif 315 316 int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len, 317 unsigned char *dest, size_t *dest_len) 318 { 319 int ret = -1; 320 int out_len = 0; 321 322 out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, 323 *dest_len); 324 if (out_len < 0) 325 goto exit_0; 326 *dest_len = out_len; 327 328 return 0; 329 exit_0: 330 return ret; 331 } 332 #ifndef STATIC 333 EXPORT_SYMBOL(lz4_decompress_unknownoutputsize); 334 335 MODULE_LICENSE("Dual BSD/GPL"); 336 MODULE_DESCRIPTION("LZ4 Decompressor"); 337 #endif 338