1 /* 2 * LZO1X Decompressor from MiniLZO 3 * 4 * Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus (at) oberhumer.com> 5 * 6 * The full LZO package can be found at: 7 * http://www.oberhumer.com/opensource/lzo/ 8 * 9 * Changed for kernel use by: 10 * Nitin Gupta <nitingupta910 (at) gmail.com> 11 * Richard Purdie <rpurdie (at) openedhand.com> 12 */ 13 14 #include <common.h> 15 #include <linux/lzo.h> 16 #include <asm/byteorder.h> 17 #include <asm/unaligned.h> 18 #include "lzodefs.h" 19 20 #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x)) 21 #define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x)) 22 #define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op) 23 24 #define COPY4(dst, src) \ 25 put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst)) 26 27 static const unsigned char lzop_magic[] = { 28 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a 29 }; 30 31 #define HEADER_HAS_FILTER 0x00000800L 32 33 34 bool lzop_is_valid_header(const unsigned char *src) 35 { 36 int i; 37 /* read magic: 9 first bytes */ 38 for (i = 0; i < ARRAY_SIZE(lzop_magic); i++) { 39 if (*src++ != lzop_magic[i]) 40 return false; 41 } 42 return true; 43 } 44 45 static inline const unsigned char *parse_header(const unsigned char *src) 46 { 47 u16 version; 48 int i; 49 50 if (!lzop_is_valid_header(src)) 51 return NULL; 52 53 /* skip header */ 54 src += 9; 55 56 /* get version (2bytes), skip library version (2), 57 * 'need to be extracted' version (2) and 58 * method (1) */ 59 version = get_unaligned_be16(src); 60 src += 7; 61 if (version >= 0x0940) 62 src++; 63 if (get_unaligned_be32(src) & HEADER_HAS_FILTER) 64 src += 4; /* filter info */ 65 66 /* skip flags, mode and mtime_low */ 67 src += 12; 68 if (version >= 0x0940) 69 src += 4; /* skip mtime_high */ 70 71 i = *src++; 72 /* don't care about the file name, and skip checksum */ 73 src += i + 4; 74 75 return src; 76 } 77 78 int lzop_decompress(const unsigned char *src, size_t src_len, 79 unsigned char *dst, size_t *dst_len) 80 { 81 unsigned char *start = dst; 82 const unsigned char *send = src + src_len; 83 u32 slen, dlen; 84 size_t tmp, remaining; 85 int r; 86 87 src = parse_header(src); 88 if (!src) 89 return LZO_E_ERROR; 90 91 remaining = *dst_len; 92 while (src < send) { 93 /* read uncompressed block size */ 94 dlen = get_unaligned_be32(src); 95 src += 4; 96 97 /* exit if last block */ 98 if (dlen == 0) { 99 *dst_len = dst - start; 100 return LZO_E_OK; 101 } 102 103 /* read compressed block size, and skip block checksum info */ 104 slen = get_unaligned_be32(src); 105 src += 8; 106 107 if (slen <= 0 || slen > dlen) 108 return LZO_E_ERROR; 109 110 /* abort if buffer ran out of room */ 111 if (dlen > remaining) 112 return LZO_E_OUTPUT_OVERRUN; 113 114 /* When the input data is not compressed at all, 115 * lzo1x_decompress_safe will fail, so call memcpy() 116 * instead */ 117 if (dlen == slen) { 118 memcpy(dst, src, slen); 119 } else { 120 /* decompress */ 121 tmp = dlen; 122 r = lzo1x_decompress_safe((u8 *)src, slen, dst, &tmp); 123 124 if (r != LZO_E_OK) { 125 *dst_len = dst - start; 126 return r; 127 } 128 129 if (dlen != tmp) 130 return LZO_E_ERROR; 131 } 132 133 src += slen; 134 dst += dlen; 135 remaining -= dlen; 136 } 137 138 return LZO_E_INPUT_OVERRUN; 139 } 140 141 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, 142 unsigned char *out, size_t *out_len) 143 { 144 const unsigned char * const ip_end = in + in_len; 145 unsigned char * const op_end = out + *out_len; 146 const unsigned char *ip = in, *m_pos; 147 unsigned char *op = out; 148 size_t t; 149 150 *out_len = 0; 151 152 if (*ip > 17) { 153 t = *ip++ - 17; 154 if (t < 4) 155 goto match_next; 156 if (HAVE_OP(t, op_end, op)) 157 goto output_overrun; 158 if (HAVE_IP(t + 1, ip_end, ip)) 159 goto input_overrun; 160 do { 161 *op++ = *ip++; 162 } while (--t > 0); 163 goto first_literal_run; 164 } 165 166 while ((ip < ip_end)) { 167 t = *ip++; 168 if (t >= 16) 169 goto match; 170 if (t == 0) { 171 if (HAVE_IP(1, ip_end, ip)) 172 goto input_overrun; 173 while (*ip == 0) { 174 t += 255; 175 ip++; 176 if (HAVE_IP(1, ip_end, ip)) 177 goto input_overrun; 178 } 179 t += 15 + *ip++; 180 } 181 if (HAVE_OP(t + 3, op_end, op)) 182 goto output_overrun; 183 if (HAVE_IP(t + 4, ip_end, ip)) 184 goto input_overrun; 185 186 COPY4(op, ip); 187 op += 4; 188 ip += 4; 189 if (--t > 0) { 190 if (t >= 4) { 191 do { 192 COPY4(op, ip); 193 op += 4; 194 ip += 4; 195 t -= 4; 196 } while (t >= 4); 197 if (t > 0) { 198 do { 199 *op++ = *ip++; 200 } while (--t > 0); 201 } 202 } else { 203 do { 204 *op++ = *ip++; 205 } while (--t > 0); 206 } 207 } 208 209 first_literal_run: 210 t = *ip++; 211 if (t >= 16) 212 goto match; 213 m_pos = op - (1 + M2_MAX_OFFSET); 214 m_pos -= t >> 2; 215 m_pos -= *ip++ << 2; 216 217 if (HAVE_LB(m_pos, out, op)) 218 goto lookbehind_overrun; 219 220 if (HAVE_OP(3, op_end, op)) 221 goto output_overrun; 222 *op++ = *m_pos++; 223 *op++ = *m_pos++; 224 *op++ = *m_pos; 225 226 goto match_done; 227 228 do { 229 match: 230 if (t >= 64) { 231 m_pos = op - 1; 232 m_pos -= (t >> 2) & 7; 233 m_pos -= *ip++ << 3; 234 t = (t >> 5) - 1; 235 if (HAVE_LB(m_pos, out, op)) 236 goto lookbehind_overrun; 237 if (HAVE_OP(t + 3 - 1, op_end, op)) 238 goto output_overrun; 239 goto copy_match; 240 } else if (t >= 32) { 241 t &= 31; 242 if (t == 0) { 243 if (HAVE_IP(1, ip_end, ip)) 244 goto input_overrun; 245 while (*ip == 0) { 246 t += 255; 247 ip++; 248 if (HAVE_IP(1, ip_end, ip)) 249 goto input_overrun; 250 } 251 t += 31 + *ip++; 252 } 253 m_pos = op - 1; 254 m_pos -= get_unaligned_le16(ip) >> 2; 255 ip += 2; 256 } else if (t >= 16) { 257 m_pos = op; 258 m_pos -= (t & 8) << 11; 259 260 t &= 7; 261 if (t == 0) { 262 if (HAVE_IP(1, ip_end, ip)) 263 goto input_overrun; 264 while (*ip == 0) { 265 t += 255; 266 ip++; 267 if (HAVE_IP(1, ip_end, ip)) 268 goto input_overrun; 269 } 270 t += 7 + *ip++; 271 } 272 m_pos -= get_unaligned_le16(ip) >> 2; 273 ip += 2; 274 if (m_pos == op) 275 goto eof_found; 276 m_pos -= 0x4000; 277 } else { 278 m_pos = op - 1; 279 m_pos -= t >> 2; 280 m_pos -= *ip++ << 2; 281 282 if (HAVE_LB(m_pos, out, op)) 283 goto lookbehind_overrun; 284 if (HAVE_OP(2, op_end, op)) 285 goto output_overrun; 286 287 *op++ = *m_pos++; 288 *op++ = *m_pos; 289 goto match_done; 290 } 291 292 if (HAVE_LB(m_pos, out, op)) 293 goto lookbehind_overrun; 294 if (HAVE_OP(t + 3 - 1, op_end, op)) 295 goto output_overrun; 296 297 if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) { 298 COPY4(op, m_pos); 299 op += 4; 300 m_pos += 4; 301 t -= 4 - (3 - 1); 302 do { 303 COPY4(op, m_pos); 304 op += 4; 305 m_pos += 4; 306 t -= 4; 307 } while (t >= 4); 308 if (t > 0) 309 do { 310 *op++ = *m_pos++; 311 } while (--t > 0); 312 } else { 313 copy_match: 314 *op++ = *m_pos++; 315 *op++ = *m_pos++; 316 do { 317 *op++ = *m_pos++; 318 } while (--t > 0); 319 } 320 match_done: 321 t = ip[-2] & 3; 322 if (t == 0) 323 break; 324 match_next: 325 if (HAVE_OP(t, op_end, op)) 326 goto output_overrun; 327 if (HAVE_IP(t + 1, ip_end, ip)) 328 goto input_overrun; 329 330 *op++ = *ip++; 331 if (t > 1) { 332 *op++ = *ip++; 333 if (t > 2) 334 *op++ = *ip++; 335 } 336 337 t = *ip++; 338 } while (ip < ip_end); 339 } 340 341 *out_len = op - out; 342 return LZO_E_EOF_NOT_FOUND; 343 344 eof_found: 345 *out_len = op - out; 346 return (ip == ip_end ? LZO_E_OK : 347 (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); 348 input_overrun: 349 *out_len = op - out; 350 return LZO_E_INPUT_OVERRUN; 351 352 output_overrun: 353 *out_len = op - out; 354 return LZO_E_OUTPUT_OVERRUN; 355 356 lookbehind_overrun: 357 *out_len = op - out; 358 return LZO_E_LOOKBEHIND_OVERRUN; 359 } 360
