tools/firmware-utils/src/buffalo-lib.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <errno.h>
  10 #include <unistd.h>
  11 #include <sys/stat.h>
  12
  13 #include "buffalo-lib.h"
  14
  15 static uint32_t crc32_table[256] =
  16 {
  17         0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
  18         0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
  19         0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
  20         0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
  21         0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
  22         0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
  23         0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
  24         0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
  25         0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
  26         0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
  27         0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
  28         0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
  29         0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
  30         0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
  31         0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
  32         0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
  33         0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
  34         0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
  35         0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
  36         0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
  37         0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
  38         0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
  39         0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
  40         0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
  41         0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
  42         0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
  43         0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
  44         0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
  45         0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
  46         0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
  47         0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
  48         0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
  49         0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
  50         0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
  51         0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
  52         0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
  53         0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
  54         0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
  55         0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
  56         0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
  57         0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
  58         0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
  59         0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
  60         0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
  61         0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
  62         0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
  63         0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
  64         0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
  65         0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
  66         0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
  67         0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
  68         0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
  69         0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
  70         0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
  71         0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
  72         0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
  73         0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
  74         0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
  75         0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
  76         0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
  77         0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
  78         0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
  79         0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
  80         0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
  81 };
  82
  83 int bcrypt_init(struct bcrypt_ctx *ctx, void *key, int keylen,
  84                 unsigned long state_len)
  85 {
  86         unsigned char *state;
  87         unsigned char *p = key;
  88         unsigned long i, j;
  89         unsigned long k = 0;
  90
  91         state = malloc(state_len);
  92         if (state == NULL)
  93                 return -1;
  94
  95         ctx->i = 0;
  96         ctx->j = 0;
  97         ctx->state = state;
  98         ctx->state_len = state_len;
  99
 100         for (i = 0; i < state_len; i++)
 101                 state[i] = i;
 102
 103         for(i = 0, j = 0; i < state_len; i++, j = (j + 1) % keylen) {
 104                 unsigned char t;
 105
 106                 t = state[i];
 107                 k = (k + p[j] + t) % state_len;
 108                 state[i] = state[k];
 109                 state[k] = t;
 110         }
 111
 112         return 0;
 113 }
 114
 115 int bcrypt_process(struct bcrypt_ctx *ctx, unsigned char *src,
 116                    unsigned char *dst, unsigned long len)
 117 {
 118         unsigned char *state = ctx->state;
 119         unsigned long state_len = ctx->state_len;
 120         unsigned char i, j;
 121         unsigned long k;
 122
 123         i = ctx->i;
 124         j = ctx->j;
 125
 126         for (k = 0; k < len; k++) {
 127                 unsigned char t;
 128
 129                 i = (i + 1) % state_len;
 130                 j = (j + state[i]) % state_len;
 131                 t = state[j];
 132                 state[j] = state[i];
 133                 state[i] = t;
 134
 135                 dst[k] = src[k] ^ state[(state[i] + state[j]) % state_len];
 136         }
 137
 138         ctx->i = i;
 139         ctx->j = j;
 140
 141         return len;
 142 }
 143
 144 void bcrypt_finish(struct bcrypt_ctx *ctx)
 145 {
 146         if (ctx->state)
 147                 free(ctx->state);
 148 }
 149
 150 int bcrypt_buf(unsigned char seed, unsigned char *key, unsigned char *src,
 151                unsigned char *dst, unsigned long len, int longstate)
 152 {
 153         unsigned char bckey[BCRYPT_MAX_KEYLEN + 1];
 154         unsigned int keylen;
 155         struct bcrypt_ctx ctx;
 156         int ret;
 157
 158         /* setup decryption key */
 159         keylen = strlen((char *) key);
 160         bckey[0] = seed;
 161         memcpy(&bckey[1], key, keylen);
 162
 163         keylen++;
 164
 165         ret = bcrypt_init(&ctx, bckey, keylen,
 166                           (longstate) ? len : BCRYPT_DEFAULT_STATE_LEN);
 167         if (ret)
 168                 return ret;
 169
 170         bcrypt_process(&ctx, src, dst, len);
 171         bcrypt_finish(&ctx);
 172
 173         return 0;
 174 }
 175
 176 uint32_t buffalo_csum(uint32_t csum, void *buf, unsigned long len)
 177 {
 178         signed char *p = buf;
 179
 180         while (len--) {
 181                 int i;
 182
 183                 csum ^= *p++;
 184                 for (i = 0; i < 8; i++)
 185                         csum = (csum >> 1) ^ ((csum & 1) ? 0xedb88320ul : 0);
 186         }
 187
 188         return csum;
 189 }
 190
 191 uint32_t buffalo_crc(void *buf, unsigned long len)
 192 {
 193         unsigned char *p = buf;
 194         unsigned long t = len;
 195         uint32_t crc = 0;
 196
 197         while (len--)
 198                 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *p++) & 0xFF];
 199
 200         while (t) {
 201                 crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ t) & 0xFF];
 202                 t >>= 8;
 203         }
 204
 205         return ~crc;
 206 }
 207
 208 unsigned long enc_compute_header_len(char *product, char *version)
 209 {
 210         return ENC_MAGIC_LEN + 1 + strlen(product) + 1 +
 211                strlen(version) + 1 + 3 * sizeof(uint32_t);
 212 }
 213
 214 unsigned long enc_compute_buf_len(char *product, char *version,
 215                                   unsigned long datalen)
 216 {
 217         unsigned long ret;
 218
 219         ret = enc_compute_header_len(product, version);
 220         ret += datalen + sizeof(uint32_t);
 221         ret += (4 - ret % 4);
 222
 223         return ret;
 224 }
 225
 226 static void put_be32(void *data, uint32_t val)
 227 {
 228         unsigned char *p = data;
 229
 230         p[0] = (val >> 24) & 0xff;
 231         p[1] = (val >> 16) & 0xff;
 232         p[2] = (val >> 8) & 0xff;
 233         p[3] = val & 0xff;
 234 }
 235
 236 static uint32_t get_be32(void *data)
 237 {
 238         unsigned char *p = data;
 239
 240         return (((uint32_t)p[0]) << 24) |
 241                (((uint32_t)p[1]) << 16) |
 242                (((uint32_t)p[2]) << 8) |
 243                ((uint32_t)p[3]);
 244 }
 245
 246 static int check_magic(void *magic)
 247 {
 248         if (!memcmp("start", magic, ENC_MAGIC_LEN))
 249                 return 0;
 250
 251         if (!memcmp("asar1", magic, ENC_MAGIC_LEN))
 252                 return 0;
 253
 254         return -1;
 255 }
 256
 257 int encrypt_buf(struct enc_param *ep, unsigned char *hdr,
 258                 unsigned char *data)
 259 {
 260         unsigned char *p;
 261         uint32_t len;
 262         int err;
 263         int ret = -1;
 264         unsigned char s;
 265
 266         p = (unsigned char *) hdr;
 267
 268         /* setup magic */
 269         len = strlen((char *) ep->magic) + 1;
 270         memcpy(p, ep->magic, len);
 271         p += len;
 272
 273         /* setup seed */
 274         *p++ = ep->seed;
 275
 276         /* put product len */
 277         len = strlen((char *) ep->product) + 1;
 278         put_be32(p, len);
 279         p += sizeof(uint32_t);
 280
 281         /* copy and crypt product name */
 282         memcpy(p, ep->product, len);
 283         err = bcrypt_buf(ep->seed, ep->key, p, p, len, ep->longstate);
 284         if (err)
 285                 goto out;
 286         s = *p;
 287         p += len;
 288
 289         /* put version length */
 290         len = strlen((char *) ep->version) + 1;
 291         put_be32(p, len);
 292         p += sizeof(uint32_t);
 293
 294         /* copy and crypt version */
 295         memcpy(p, ep->version, len);
 296         err = bcrypt_buf(s, ep->key, p, p, len, ep->longstate);
 297         if (err)
 298                 goto out;
 299         s = *p;
 300         p += len;
 301
 302         /* put data length */
 303         put_be32(p, ep->datalen);
 304
 305         /* encrypt data */
 306         err = bcrypt_buf(s, ep->key, data, data, ep->datalen, ep->longstate);
 307         if (err)
 308                 goto out;
 309
 310         /* put checksum */
 311         put_be32(&data[ep->datalen], ep->csum);
 312
 313         ret = 0;
 314
 315 out:
 316         return ret;
 317 }
 318
 319 int decrypt_buf(struct enc_param *ep, unsigned char *data,
 320                 unsigned long datalen)
 321 {
 322         unsigned char *p;
 323         uint32_t prod_len;
 324         uint32_t ver_len;
 325         uint32_t len;
 326         uint32_t csum;
 327         ssize_t remain;
 328         int err;
 329         int ret = -1;
 330
 331 #define CHECKLEN(_l) do {               \
 332         len = (_l);                     \
 333         if (remain < len) {             \
 334                 goto out;               \
 335         }                               \
 336 } while (0)
 337
 338 #define INCP() do {                     \
 339         p += len;                       \
 340         remain -= len;                  \
 341 } while (0)
 342
 343         remain = datalen;
 344         p = data;
 345
 346         CHECKLEN(ENC_MAGIC_LEN);
 347         err = check_magic(p);
 348         if (err)
 349                 goto out;
 350         memcpy(ep->magic, p, ENC_MAGIC_LEN);
 351         INCP();
 352
 353         CHECKLEN(1);
 354         ep->seed = *p;
 355         INCP();
 356
 357         CHECKLEN(sizeof(uint32_t));
 358         prod_len = get_be32(p);
 359         if (prod_len > ENC_PRODUCT_LEN)
 360                 goto out;
 361         INCP();
 362
 363         CHECKLEN(prod_len);
 364         memcpy(ep->product, p, prod_len);
 365         INCP();
 366
 367         CHECKLEN(sizeof(uint32_t));
 368         ver_len = get_be32(p);
 369         if (ver_len > ENC_VERSION_LEN)
 370                 goto out;
 371         INCP();
 372
 373         CHECKLEN(ver_len);
 374         memcpy(ep->version, p, ver_len);
 375         INCP();
 376
 377         CHECKLEN(sizeof(uint32_t));
 378         ep->datalen = get_be32(p);
 379         INCP();
 380
 381         /* decrypt data */
 382         CHECKLEN(ep->datalen);
 383         err = bcrypt_buf(ep->version[0], ep->key, p, data, ep->datalen,
 384                          ep->longstate);
 385         if (err)
 386                 goto out;
 387         INCP();
 388
 389         CHECKLEN(sizeof(uint32_t));
 390         ep->csum = get_be32(p);
 391         INCP();
 392
 393         csum = buffalo_csum(ep->datalen, data, ep->datalen);
 394         if (csum != ep->csum)
 395                 goto out;
 396
 397         /* decrypt product name */
 398         err = bcrypt_buf(ep->product[0], ep->key, ep->version, ep->version,
 399                          ver_len, ep->longstate);
 400         if (err)
 401                 goto out;
 402
 403         /* decrypt version */
 404         err = bcrypt_buf(ep->seed, ep->key, ep->product, ep->product, prod_len,
 405                          ep->longstate);
 406         if (err)
 407                 goto out;
 408
 409         ret = 0;
 410 out:
 411         return ret;
 412
 413 #undef CHECKLEN
 414 #undef INCP
 415 }
 416
 417 ssize_t get_file_size(char *name)
 418 {
 419         struct stat st;
 420         int err;
 421
 422         err = stat(name, &st);
 423         if (err)
 424                 return -1;
 425
 426         return st.st_size;
 427 }
 428
 429 int read_file_to_buf(char *name, void *buf, ssize_t buflen)
 430 {
 431         FILE *f;
 432         size_t done;
 433         int ret = -1;
 434
 435         f = fopen(name, "r");
 436         if (f == NULL)
 437                 goto out;
 438
 439         errno = 0;
 440         done = fread(buf, buflen, 1, f);
 441         if (done != 1)
 442                 goto close;
 443
 444         ret = 0;
 445
 446 close:
 447         fclose(f);
 448 out:
 449         return ret;
 450 }
 451
 452 int write_buf_to_file(char *name, void *buf, ssize_t buflen)
 453 {
 454         FILE *f;
 455         size_t done;
 456         int ret = -1;
 457
 458         f = fopen(name, "w");
 459         if (f == NULL)
 460                 goto out;
 461
 462         errno = 0;
 463         done = fwrite(buf, buflen, 1, f);
 464         if (done != 1)
 465                 goto close;
 466
 467         ret = 0;
 468
 469 close:
 470         fflush(f);
 471         fclose(f);
 472         if (ret)
 473                 unlink(name);
 474 out:
 475         return ret;
 476 }