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