package/utils/fritz-tools/src/fritz_tffs_nand_read.c

   1 /*
   2  * A tool for reading the TFFS partitions (a name-value storage usually
   3  * found in AVM Fritz!Box based devices) on nand flash.
   4  *
   5  * Copyright (c) 2018 Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.DE>
   6  *
   7  * Based on the fritz_tffs_read tool:
   8  *     Copyright (c) 2015-2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
   9  * and on the TFFS 2.0 kernel driver from AVM:
  10  *     Copyright (c) 2004-2007 AVM GmbH <fritzbox_info@avm.de>
  11  * and the TFFS 3.0 kernel driver from AVM:
  12  *     Copyright (C) 2004-2014 AVM GmbH <fritzbox_info@avm.de>
  13  * and the OpenWrt TFFS kernel driver:
  14  *     Copyright (c) 2013 John Crispin <john@phrozen.org>
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License along
  27  * with this program; if not, write to the Free Software Foundation, Inc.,
  28  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  29  */
  30
  31 #include <stdbool.h>
  32 #include <stddef.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <stdint.h>
  36 #include <string.h>
  37 #include <libgen.h>
  38 #include <getopt.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41 #include <endian.h>
  42 #include <sys/ioctl.h>
  43 #include <sys/types.h>
  44 #include <sys/stat.h>
  45 #include <arpa/inet.h>
  46 #include <mtd/mtd-user.h>
  47 #include <assert.h>
  48
  49 #define DEFAULT_TFFS_SIZE       (256 * 1024)
  50
  51 #define TFFS_ID_END             0xffffffff
  52 #define TFFS_ID_TABLE_NAME      0x000001ff
  53
  54 #define TFFS_BLOCK_HEADER_MAGIC 0x41564d5f54464653ULL
  55 #define TFFS_VERSION            0x0003
  56 #define TFFS_ENTRY_HEADER_SIZE  0x18
  57 #define TFFS_MAXIMUM_SEGMENT_SIZE       (0x800 - TFFS_ENTRY_HEADER_SIZE)
  58
  59 #define TFFS_SECTOR_SIZE 0x0800
  60 #define TFFS_SECTOR_OOB_SIZE 0x0040
  61 #define TFFS_SECTORS_PER_PAGE 2
  62
  63 #define TFFS_SEGMENT_CLEARED 0xffffffff
  64
  65 static char *progname;
  66 static char *mtddev;
  67 static char *name_filter = NULL;
  68 static bool show_all = false;
  69 static bool print_all_key_names = false;
  70 static bool read_oob_sector_health = false;
  71 static bool swap_bytes = false;
  72 static uint8_t readbuf[TFFS_SECTOR_SIZE];
  73 static uint8_t oobbuf[TFFS_SECTOR_OOB_SIZE];
  74 static uint32_t blocksize;
  75 static int mtdfd;
  76 static uint32_t num_sectors;
  77 static uint8_t *sectors;
  78
  79 static inline void sector_mark_bad(int num)
  80 {
  81         sectors[num / 8] &= ~(0x80 >> (num % 8));
  82 };
  83
  84 static inline uint8_t sector_get_good(int num)
  85 {
  86         return sectors[num / 8] & 0x80 >> (num % 8);
  87 };
  88
  89 struct tffs_entry_segment {
  90         uint32_t len;
  91         void *val;
  92 };
  93
  94 struct tffs_entry {
  95         uint32_t len;
  96         void *val;
  97 };
  98
  99 struct tffs_name_table_entry {
 100         uint32_t id;
 101         char *val;
 102 };
 103
 104 struct tffs_key_name_table {
 105         uint32_t size;
 106         struct tffs_name_table_entry *entries;
 107 };
 108
 109 static inline uint8_t read_uint8(void *buf, ptrdiff_t off)
 110 {
 111         return *(uint8_t *)(buf + off);
 112 }
 113
 114 static inline uint32_t read_uint32(void *buf, ptrdiff_t off)
 115 {
 116         uint32_t tmp = *(uint32_t *)(buf + off);
 117         if (swap_bytes) {
 118                 tmp = be32toh(tmp);
 119         }
 120         return tmp;
 121 }
 122
 123 static inline uint64_t read_uint64(void *buf, ptrdiff_t off)
 124 {
 125         uint64_t tmp = *(uint64_t *)(buf + off);
 126         if (swap_bytes) {
 127                 tmp = be64toh(tmp);
 128         }
 129         return tmp;
 130 }
 131
 132 static int read_sector(off_t pos)
 133 {
 134         if (pread(mtdfd, readbuf, TFFS_SECTOR_SIZE, pos) != TFFS_SECTOR_SIZE) {
 135                 return -1;
 136         }
 137
 138         return 0;
 139 }
 140
 141 static int read_sectoroob(off_t pos)
 142 {
 143         struct mtd_oob_buf oob = {
 144                 .start = pos,
 145                 .length = TFFS_SECTOR_OOB_SIZE,
 146                 .ptr = oobbuf
 147         };
 148
 149         if (ioctl(mtdfd, MEMREADOOB, &oob) < 0) {
 150                 return -1;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static inline uint32_t get_walk_size(uint32_t entry_len)
 157 {
 158         return (entry_len + 3) & ~0x03;
 159 }
 160
 161 static void print_entry_value(const struct tffs_entry *entry)
 162 {
 163         /* These are NOT NULL terminated. */
 164         fwrite(entry->val, 1, entry->len, stdout);
 165 }
 166
 167 static int find_entry(uint32_t id, struct tffs_entry *entry)
 168 {
 169         uint32_t rev = 0;
 170         uint32_t num_segments = 0;
 171         struct tffs_entry_segment *segments = NULL;
 172
 173         off_t pos = 0;
 174         uint8_t block_end = 0;
 175         for (uint32_t sector = 0; sector < num_sectors; sector++, pos += TFFS_SECTOR_SIZE) {
 176                 if (block_end) {
 177                         if (pos % blocksize == 0) {
 178                                 block_end = 0;
 179                         }
 180                 } else if (sector_get_good(sector)) {
 181                         if (read_sectoroob(pos) || read_sector(pos)) {
 182                                 fprintf(stderr, "ERROR: sector isn't readable, but has been previously!\n");
 183                                 exit(EXIT_FAILURE);
 184                         }
 185                         uint32_t read_id = read_uint32(readbuf, 0x00);
 186                         uint32_t read_len = read_uint32(readbuf, 0x04);
 187                         uint32_t read_rev = read_uint32(readbuf, 0x0c);
 188                         if (read_oob_sector_health) {
 189                                 uint32_t oob_id = read_uint32(oobbuf, 0x02);
 190                                 uint32_t oob_len = read_uint32(oobbuf, 0x06);
 191                                 uint32_t oob_rev = read_uint32(oobbuf, 0x0a);
 192
 193                                 if (oob_id != read_id || oob_len != read_len || oob_rev != read_rev) {
 194                                         fprintf(stderr, "Warning: sector has inconsistent metadata\n");
 195                                         continue;
 196                                 }
 197                         }
 198                         if (read_id == TFFS_ID_END) {
 199                                 /* no more entries in this block */
 200                                 block_end = 1;
 201                                 continue;
 202                         }
 203                         if (read_len > TFFS_MAXIMUM_SEGMENT_SIZE) {
 204                                 fprintf(stderr, "Warning: segment is longer than possible\n");
 205                                 continue;
 206                         }
 207                         if (read_id == id) {
 208                                 if (read_rev < rev) {
 209                                         /* obsolete revision => ignore this */
 210                                         continue;
 211                                 }
 212                                 if (read_rev > rev) {
 213                                         /* newer revision => clear old data */
 214                                         for (uint32_t i = 0; i < num_segments; i++) {
 215                                                 free(segments[i].val);
 216                                         }
 217                                         free (segments);
 218                                         rev = read_rev;
 219                                         num_segments = 0;
 220                                         segments = NULL;
 221                                 }
 222
 223                                 uint32_t seg = read_uint32(readbuf, 0x10);
 224
 225                                 if (seg == TFFS_SEGMENT_CLEARED) {
 226                                         continue;
 227                                 }
 228
 229                                 uint32_t next_seg = read_uint32(readbuf, 0x14);
 230
 231                                 uint32_t new_num_segs = next_seg == 0 ? seg + 1 : next_seg + 1;
 232                                 if (new_num_segs > num_segments) {
 233                                         segments = realloc(segments, new_num_segs * sizeof(struct tffs_entry_segment));
 234                                         memset(segments + (num_segments * sizeof(struct tffs_entry_segment)), 0x0,
 235                                                         (new_num_segs - num_segments) * sizeof(struct tffs_entry_segment));
 236                                         num_segments = new_num_segs;
 237                                 }
 238                                 segments[seg].len = read_len;
 239                                 segments[seg].val = malloc(read_len);
 240                                 memcpy(segments[seg].val, readbuf + TFFS_ENTRY_HEADER_SIZE, read_len);
 241                         }
 242                 }
 243         }
 244
 245         if (num_segments == 0) {
 246                 return 0;
 247         }
 248
 249         assert (segments != NULL);
 250
 251         uint32_t len = 0;
 252         for (uint32_t i = 0; i < num_segments; i++) {
 253                 if (segments[i].val == NULL) {
 254                         /* missing segment */
 255                         return 0;
 256                 }
 257
 258                 len += segments[i].len;
 259         }
 260
 261         void *p = malloc(len);
 262         entry->val = p;
 263         entry->len = len;
 264         for (uint32_t i = 0; i < num_segments; i++) {
 265                 memcpy(p, segments[i].val, segments[i].len);
 266                 p += segments[i].len;
 267         }
 268
 269         return 1;
 270 }
 271
 272 static void parse_key_names(struct tffs_entry *names_entry,
 273                              struct tffs_key_name_table *key_names)
 274 {
 275         uint32_t pos = 0, i = 0;
 276         struct tffs_name_table_entry *name_item;
 277
 278         key_names->entries = NULL;
 279
 280         do {
 281                 key_names->entries = realloc(key_names->entries,
 282                          sizeof(struct tffs_name_table_entry) * (i + 1));
 283                 if (key_names->entries == NULL) {
 284                         fprintf(stderr, "ERROR: memory allocation failed!\n");
 285                         exit(EXIT_FAILURE);
 286                 }
 287                 name_item = &key_names->entries[i];
 288
 289                 name_item->id = read_uint32(names_entry->val, pos);
 290                 pos += sizeof(uint32_t);
 291                 name_item->val = strdup((const char *)(names_entry->val + pos));
 292
 293                 /*
 294                  * There is no "length" field because the string values are
 295                  * simply NULL-terminated -> strlen() gives us the size.
 296                  */
 297                 pos += get_walk_size(strlen(name_item->val) + 1);
 298
 299                 ++i;
 300         } while (pos < names_entry->len);
 301
 302         key_names->size = i;
 303 }
 304
 305 static void show_all_key_names(struct tffs_key_name_table *key_names)
 306 {
 307         for (uint32_t i = 0; i < key_names->size; i++)
 308                 printf("%s\n", key_names->entries[i].val);
 309 }
 310
 311 static int show_all_key_value_pairs(struct tffs_key_name_table *key_names)
 312 {
 313         uint8_t has_value = 0;
 314         struct tffs_entry tmp;
 315
 316         for (uint32_t i = 0; i < key_names->size; i++) {
 317                 if (find_entry(key_names->entries[i].id, &tmp)) {
 318                         printf("%s=", (const char *)key_names->entries[i].val);
 319                         print_entry_value(&tmp);
 320                         printf("\n");
 321                         has_value++;
 322                         free(tmp.val);
 323                 }
 324         }
 325
 326         if (!has_value) {
 327                 fprintf(stderr, "ERROR: no values found!\n");
 328                 return EXIT_FAILURE;
 329         }
 330
 331         return EXIT_SUCCESS;
 332 }
 333
 334 static int show_matching_key_value(struct tffs_key_name_table *key_names)
 335 {
 336         struct tffs_entry tmp;
 337         const char *name;
 338
 339         for (uint32_t i = 0; i < key_names->size; i++) {
 340                 name = key_names->entries[i].val;
 341
 342                 if (strcmp(name, name_filter) == 0) {
 343                         if (find_entry(key_names->entries[i].id, &tmp)) {
 344                                 print_entry_value(&tmp);
 345                                 printf("\n");
 346                                 free(tmp.val);
 347                                 return EXIT_SUCCESS;
 348                         } else {
 349                                 fprintf(stderr,
 350                                         "ERROR: no value found for name %s!\n",
 351                                         name);
 352                                 return EXIT_FAILURE;
 353                         }
 354                 }
 355         }
 356
 357         fprintf(stderr, "ERROR: Unknown key name %s!\n", name_filter);
 358         return EXIT_FAILURE;
 359 }
 360
 361 static int check_sector(off_t pos)
 362 {
 363         if (!read_oob_sector_health) {
 364                 return 1;
 365         }
 366         if (read_sectoroob(pos)) {
 367                 return 0;
 368         }
 369         if (read_uint8(oobbuf, 0x00) != 0xff) {
 370                 /* block is bad */
 371                 return 0;
 372         }
 373         if (read_uint8(oobbuf, 0x01) != 0xff) {
 374                 /* sector is bad */
 375                 return 0;
 376         }
 377         return 1;
 378 }
 379
 380 static int check_block(off_t pos, uint32_t sector)
 381 {
 382         if (!check_sector(pos)) {
 383                 return 0;
 384         }
 385         if (read_sector(pos)) {
 386                 return 0;
 387         }
 388         if (read_uint64(readbuf, 0x00) != TFFS_BLOCK_HEADER_MAGIC) {
 389                 fprintf(stderr, "Warning: block without magic header. Skipping block\n");
 390                 return 0;
 391         }
 392         if (read_uint32(readbuf, 0x0c) != TFFS_SECTORS_PER_PAGE) {
 393                 fprintf(stderr, "Warning: block with wrong number of sectors per page. Skipping block\n");
 394                 return 0;
 395         }
 396
 397         uint32_t num_hdr_bad = read_uint32(readbuf, 0x0c);
 398         for (uint32_t i = 0; i < num_hdr_bad; i++) {
 399                 uint32_t bad = sector + read_uint64(readbuf, 0x1c + sizeof(uint64_t)*i);
 400                 sector_mark_bad(bad);
 401         }
 402
 403         return 1;
 404 }
 405
 406 static int scan_mtd(void)
 407 {
 408         struct mtd_info_user info;
 409
 410         if (ioctl(mtdfd, MEMGETINFO, &info)) {
 411                 return 0;
 412         }
 413
 414         blocksize = info.erasesize;
 415
 416         num_sectors = info.size / TFFS_SECTOR_SIZE;
 417         sectors = malloc((num_sectors + 7) / 8);
 418         if (sectors == NULL) {
 419                 fprintf(stderr, "ERROR: memory allocation failed!\n");
 420                 exit(EXIT_FAILURE);
 421         }
 422         memset(sectors, 0xff, (num_sectors + 7) / 8);
 423
 424         uint32_t sector = 0, valid_blocks = 0;
 425         uint8_t block_ok = 0;
 426         for (off_t pos = 0; pos < info.size; sector++, pos += TFFS_SECTOR_SIZE) {
 427                 if (pos % info.erasesize == 0) {
 428                         block_ok = check_block(pos, sector);
 429                         /* first sector of the block contains metadata
 430                            => handle it like a bad sector */
 431                         sector_mark_bad(sector);
 432                         if (block_ok) {
 433                                 valid_blocks++;
 434                         }
 435                 } else if (!block_ok || !sector_get_good(sector) || !check_sector(pos)) {
 436                         sector_mark_bad(sector);
 437                 }
 438         }
 439
 440         return valid_blocks;
 441 }
 442
 443 static void usage(int status)
 444 {
 445         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
 446
 447         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
 448         fprintf(stream,
 449         "\n"
 450         "Options:\n"
 451         "  -a              list all key value pairs found in the TFFS file/device\n"
 452         "  -d <mtd>        inspect the TFFS on mtd device <mtd>\n"
 453         "  -h              show this screen\n"
 454         "  -l              list all supported keys\n"
 455         "  -n <key name>   display the value of the given key\n"
 456         "  -o              read OOB information about sector health\n"
 457         );
 458
 459         exit(status);
 460 }
 461
 462 static void parse_options(int argc, char *argv[])
 463 {
 464         while (1) {
 465                 int c;
 466
 467                 c = getopt(argc, argv, "abd:hln:o");
 468                 if (c == -1)
 469                         break;
 470
 471                 switch (c) {
 472                 case 'a':
 473                         show_all = true;
 474                         name_filter = NULL;
 475                         print_all_key_names = false;
 476                         break;
 477                 case 'b':
 478                         swap_bytes = 1;
 479                         break;
 480                 case 'd':
 481                         mtddev = optarg;
 482                         break;
 483                 case 'h':
 484                         usage(EXIT_SUCCESS);
 485                         break;
 486                 case 'l':
 487                         print_all_key_names = true;
 488                         show_all = false;
 489                         name_filter = NULL;
 490                         break;
 491                 case 'n':
 492                         name_filter = optarg;
 493                         show_all = false;
 494                         print_all_key_names = false;
 495                         break;
 496                 case 'o':
 497                         read_oob_sector_health = true;
 498                         break;
 499                 default:
 500                         usage(EXIT_FAILURE);
 501                         break;
 502                 }
 503         }
 504
 505         if (!mtddev) {
 506                 fprintf(stderr, "ERROR: No input file (-d <file>) given!\n");
 507                 usage(EXIT_FAILURE);
 508         }
 509
 510         if (!show_all && !name_filter && !print_all_key_names) {
 511                 fprintf(stderr,
 512                         "ERROR: either -l, -a or -n <key name> is required!\n");
 513                 usage(EXIT_FAILURE);
 514         }
 515 }
 516
 517 int main(int argc, char *argv[])
 518 {
 519         int ret = EXIT_FAILURE;
 520         struct tffs_entry name_table;
 521         struct tffs_key_name_table key_names;
 522
 523         progname = basename(argv[0]);
 524
 525         parse_options(argc, argv);
 526
 527         mtdfd = open(mtddev, O_RDONLY);
 528         if (mtdfd < 0) {
 529                 fprintf(stderr, "ERROR: Failed to open tffs device %s\n",
 530                         mtddev);
 531                 goto out;
 532         }
 533
 534         if (!scan_mtd()) {
 535                 fprintf(stderr, "ERROR: Parsing blocks from tffs device %s failed\n", mtddev);
 536                 fprintf(stderr, "       Is byte-swapping (-b) required?\n");
 537                 goto out_close;
 538         }
 539
 540         if (!find_entry(TFFS_ID_TABLE_NAME, &name_table)) {
 541                 fprintf(stderr, "ERROR: No name table found on tffs device %s\n",
 542                         mtddev);
 543                 goto out_free_sectors;
 544         }
 545
 546         parse_key_names(&name_table, &key_names);
 547         if (key_names.size < 1) {
 548                 fprintf(stderr, "ERROR: No name table found on tffs device %s\n",
 549                         mtddev);
 550                 goto out_free_entry;
 551         }
 552
 553         if (print_all_key_names) {
 554                 show_all_key_names(&key_names);
 555                 ret = EXIT_SUCCESS;
 556         } else if (show_all) {
 557                 ret = show_all_key_value_pairs(&key_names);
 558         } else {
 559                 ret = show_matching_key_value(&key_names);
 560         }
 561
 562         free(key_names.entries);
 563 out_free_entry:
 564         free(name_table.val);
 565 out_free_sectors:
 566         free(sectors);
 567 out_close:
 568         close(mtdfd);
 569 out:
 570         return ret;
 571 }