lib/ext2fs/csum.c

   1 /*
   2  * csum.c --- checksumming of ext3 structures
   3  *
   4  * Copyright (C) 2006 Cluster File Systems, Inc.
   5  * Copyright (C) 2006, 2007 by Andreas Dilger <adilger@clusterfs.com>
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Library
   9  * General Public License, version 2.
  10  * %End-Header%
  11  */
  12
  13 #include "config.h"
  14 #if HAVE_SYS_TYPES_H
  15 #include <sys/types.h>
  16 #endif
  17
  18 #include "ext2_fs.h"
  19 #include "ext2fs.h"
  20 #include "crc16.h"
  21 #include <assert.h>
  22
  23 #ifndef offsetof
  24 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
  25 #endif
  26
  27 #ifdef DEBUG
  28 #define STATIC
  29 #else
  30 #define STATIC static
  31 #endif
  32
  33 void ext2fs_init_csum_seed(ext2_filsys fs)
  34 {
  35         if (ext2fs_has_feature_csum_seed(fs->super))
  36                 fs->csum_seed = fs->super->s_checksum_seed;
  37         else if (ext2fs_has_feature_metadata_csum(fs->super) ||
  38                  ext2fs_has_feature_ea_inode(fs->super))
  39                 fs->csum_seed = ext2fs_crc32c_le(~0, fs->super->s_uuid,
  40                                                  sizeof(fs->super->s_uuid));
  41 }
  42
  43 static __u32 ext2fs_mmp_csum(ext2_filsys fs, struct mmp_struct *mmp)
  44 {
  45         int offset = offsetof(struct mmp_struct, mmp_checksum);
  46
  47         return ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)mmp, offset);
  48 }
  49
  50 int ext2fs_mmp_csum_verify(ext2_filsys fs, struct mmp_struct *mmp)
  51 {
  52         __u32 calculated;
  53
  54         if (!ext2fs_has_feature_metadata_csum(fs->super))
  55                 return 1;
  56
  57         calculated = ext2fs_mmp_csum(fs, mmp);
  58
  59         return ext2fs_le32_to_cpu(mmp->mmp_checksum) == calculated;
  60 }
  61
  62 errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp)
  63 {
  64         __u32 crc;
  65
  66         if (!ext2fs_has_feature_metadata_csum(fs->super))
  67                 return 0;
  68
  69         crc = ext2fs_mmp_csum(fs, mmp);
  70         mmp->mmp_checksum = ext2fs_cpu_to_le32(crc);
  71
  72         return 0;
  73 }
  74
  75 int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb)
  76 {
  77         if (!ext2fs_has_feature_metadata_csum(fs->super))
  78                 return 1;
  79
  80         return sb->s_checksum_type == EXT2_CRC32C_CHKSUM;
  81 }
  82
  83 static __u32 ext2fs_superblock_csum(ext2_filsys fs EXT2FS_ATTR((unused)),
  84                                     struct ext2_super_block *sb)
  85 {
  86         int offset = offsetof(struct ext2_super_block, s_checksum);
  87
  88         return ext2fs_crc32c_le(~0, (unsigned char *)sb, offset);
  89 }
  90
  91 /* NOTE: The input to this function MUST be in LE order */
  92 int ext2fs_superblock_csum_verify(ext2_filsys fs, struct ext2_super_block *sb)
  93 {
  94         __u32 flag, calculated;
  95
  96         if (fs->flags & EXT2_FLAG_SWAP_BYTES)
  97                 flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
  98         else
  99                 flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
 100
 101         if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
 102                 return 1;
 103
 104         calculated = ext2fs_superblock_csum(fs, sb);
 105
 106         return ext2fs_le32_to_cpu(sb->s_checksum) == calculated;
 107 }
 108
 109 /* NOTE: The input to this function MUST be in LE order */
 110 errcode_t ext2fs_superblock_csum_set(ext2_filsys fs,
 111                                      struct ext2_super_block *sb)
 112 {
 113         __u32 flag, crc;
 114
 115         if (fs->flags & EXT2_FLAG_SWAP_BYTES)
 116                 flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
 117         else
 118                 flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
 119
 120         if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
 121                 return 0;
 122
 123         crc = ext2fs_superblock_csum(fs, sb);
 124         sb->s_checksum = ext2fs_cpu_to_le32(crc);
 125
 126         return 0;
 127 }
 128
 129 static errcode_t ext2fs_ext_attr_block_csum(ext2_filsys fs,
 130                                             ext2_ino_t inum EXT2FS_ATTR((unused)),
 131                                             blk64_t block,
 132                                             struct ext2_ext_attr_header *hdr,
 133                                             __u32 *crc)
 134 {
 135         char *buf = (char *)hdr;
 136         __u32 old_crc = hdr->h_checksum;
 137
 138         hdr->h_checksum = 0;
 139         block = ext2fs_cpu_to_le64(block);
 140         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&block,
 141                                 sizeof(block));
 142         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, fs->blocksize);
 143         hdr->h_checksum = old_crc;
 144
 145         return 0;
 146 }
 147
 148 int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 149                                       blk64_t block,
 150                                       struct ext2_ext_attr_header *hdr)
 151 {
 152         __u32 calculated;
 153         errcode_t retval;
 154
 155         if (!ext2fs_has_feature_metadata_csum(fs->super))
 156                 return 1;
 157
 158         retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &calculated);
 159         if (retval)
 160                 return 0;
 161
 162         return ext2fs_le32_to_cpu(hdr->h_checksum) == calculated;
 163 }
 164
 165 errcode_t ext2fs_ext_attr_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 166                                          blk64_t block,
 167                                          struct ext2_ext_attr_header *hdr)
 168 {
 169         errcode_t retval;
 170         __u32 crc;
 171
 172         if (!ext2fs_has_feature_metadata_csum(fs->super))
 173                 return 0;
 174
 175         retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &crc);
 176         if (retval)
 177                 return retval;
 178         hdr->h_checksum = ext2fs_cpu_to_le32(crc);
 179         return 0;
 180 }
 181
 182 static __u16 do_nothing16(__u16 x)
 183 {
 184         return x;
 185 }
 186
 187 static __u16 disk_to_host16(__u16 x)
 188 {
 189         return ext2fs_le16_to_cpu(x);
 190 }
 191
 192 static errcode_t __get_dx_countlimit(ext2_filsys fs,
 193                                      struct ext2_dir_entry *dirent,
 194                                      struct ext2_dx_countlimit **cc,
 195                                      int *offset,
 196                                      int need_swab)
 197 {
 198         struct ext2_dir_entry *dp;
 199         struct ext2_dx_root_info *root;
 200         struct ext2_dx_countlimit *c;
 201         int count_offset, max_sane_entries;
 202         unsigned int rec_len;
 203         __u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
 204
 205         rec_len = translate(dirent->rec_len);
 206
 207         if (rec_len == fs->blocksize && translate(dirent->name_len) == 0)
 208                 count_offset = 8;
 209         else if (rec_len == 12) {
 210                 dp = (struct ext2_dir_entry *)(((char *)dirent) + rec_len);
 211                 rec_len = translate(dp->rec_len);
 212                 if (rec_len != fs->blocksize - 12)
 213                         return EXT2_ET_DB_NOT_FOUND;
 214                 root = (struct ext2_dx_root_info *)(((char *)dp + 12));
 215                 if (root->reserved_zero ||
 216                     root->info_length != sizeof(struct ext2_dx_root_info))
 217                         return EXT2_ET_DB_NOT_FOUND;
 218                 count_offset = 32;
 219         } else
 220                 return EXT2_ET_DB_NOT_FOUND;
 221
 222         c = (struct ext2_dx_countlimit *)(((char *)dirent) + count_offset);
 223         max_sane_entries = (fs->blocksize - count_offset) /
 224                            sizeof(struct ext2_dx_entry);
 225         if (ext2fs_le16_to_cpu(c->limit) > max_sane_entries ||
 226             ext2fs_le16_to_cpu(c->count) > max_sane_entries)
 227                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 228
 229         if (offset)
 230                 *offset = count_offset;
 231         if (cc)
 232                 *cc = c;
 233
 234         return 0;
 235 }
 236
 237 errcode_t ext2fs_get_dx_countlimit(ext2_filsys fs,
 238                                    struct ext2_dir_entry *dirent,
 239                                    struct ext2_dx_countlimit **cc,
 240                                    int *offset)
 241 {
 242         return __get_dx_countlimit(fs, dirent, cc, offset, 0);
 243 }
 244
 245 void ext2fs_initialize_dirent_tail(ext2_filsys fs,
 246                                    struct ext2_dir_entry_tail *t)
 247 {
 248         memset(t, 0, sizeof(struct ext2_dir_entry_tail));
 249         ext2fs_set_rec_len(fs, sizeof(struct ext2_dir_entry_tail),
 250                            (struct ext2_dir_entry *)t);
 251         t->det_reserved_name_len = EXT2_DIR_NAME_LEN_CSUM;
 252 }
 253
 254 static errcode_t __get_dirent_tail(ext2_filsys fs,
 255                                    struct ext2_dir_entry *dirent,
 256                                    struct ext2_dir_entry_tail **tt,
 257                                    int need_swab)
 258 {
 259         struct ext2_dir_entry *d;
 260         void *top;
 261         struct ext2_dir_entry_tail *t;
 262         unsigned int rec_len;
 263         errcode_t retval = 0;
 264         __u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
 265
 266         d = dirent;
 267         top = EXT2_DIRENT_TAIL(dirent, fs->blocksize);
 268
 269         rec_len = translate(d->rec_len);
 270         while (rec_len && !(rec_len & 0x3)) {
 271                 d = (struct ext2_dir_entry *)(((char *)d) + rec_len);
 272                 if ((void *)d >= top)
 273                         break;
 274                 rec_len = translate(d->rec_len);
 275         }
 276
 277         if (d != top)
 278                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 279
 280         t = (struct ext2_dir_entry_tail *)d;
 281         if (t->det_reserved_zero1 ||
 282             translate(t->det_rec_len) != sizeof(struct ext2_dir_entry_tail) ||
 283             translate(t->det_reserved_name_len) != EXT2_DIR_NAME_LEN_CSUM)
 284                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 285
 286         if (tt)
 287                 *tt = t;
 288         return retval;
 289 }
 290
 291 int ext2fs_dirent_has_tail(ext2_filsys fs, struct ext2_dir_entry *dirent)
 292 {
 293         return __get_dirent_tail(fs, dirent, NULL, 0) == 0;
 294 }
 295
 296 static errcode_t ext2fs_dirent_csum(ext2_filsys fs, ext2_ino_t inum,
 297                                     struct ext2_dir_entry *dirent, __u32 *crc,
 298                                     int size)
 299 {
 300         errcode_t retval;
 301         char *buf = (char *)dirent;
 302         __u32 gen;
 303         struct ext2_inode inode;
 304
 305         retval = ext2fs_read_inode(fs, inum, &inode);
 306         if (retval)
 307                 return retval;
 308
 309         inum = ext2fs_cpu_to_le32(inum);
 310         gen = ext2fs_cpu_to_le32(inode.i_generation);
 311         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 312                                 sizeof(inum));
 313         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 314         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 315
 316         return 0;
 317 }
 318
 319 int ext2fs_dirent_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 320                               struct ext2_dir_entry *dirent)
 321 {
 322         errcode_t retval;
 323         __u32 calculated;
 324         struct ext2_dir_entry_tail *t;
 325
 326         retval = __get_dirent_tail(fs, dirent, &t, 1);
 327         if (retval)
 328                 return 1;
 329
 330         /*
 331          * The checksum field is overlaid with the dirent->name field
 332          * so the swapfs.c functions won't change the endianness.
 333          */
 334         retval = ext2fs_dirent_csum(fs, inum, dirent, &calculated,
 335                                     (char *)t - (char *)dirent);
 336         if (retval)
 337                 return 0;
 338         return ext2fs_le32_to_cpu(t->det_checksum) == calculated;
 339 }
 340
 341 static errcode_t ext2fs_dirent_csum_set(ext2_filsys fs, ext2_ino_t inum,
 342                                         struct ext2_dir_entry *dirent)
 343 {
 344         errcode_t retval;
 345         __u32 crc;
 346         struct ext2_dir_entry_tail *t;
 347
 348         retval = __get_dirent_tail(fs, dirent, &t, 1);
 349         if (retval)
 350                 return retval;
 351
 352         /* swapfs.c functions don't change the checksum endianness */
 353         retval = ext2fs_dirent_csum(fs, inum, dirent, &crc,
 354                                     (char *)t - (char *)dirent);
 355         if (retval)
 356                 return retval;
 357         t->det_checksum = ext2fs_cpu_to_le32(crc);
 358         return 0;
 359 }
 360
 361 errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
 362                          struct ext2_dir_entry *dirent,
 363                          __u32 *crc, struct ext2_dx_tail **ret_t)
 364 {
 365         errcode_t retval;
 366         char *buf = (char *)dirent;
 367         int size;
 368         __u32 gen, dummy_csum = 0;
 369         struct ext2_inode inode;
 370         struct ext2_dx_tail *t;
 371         struct ext2_dx_countlimit *c;
 372         int count_offset, limit, count;
 373
 374         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 375         if (retval)
 376                 return retval;
 377         limit = ext2fs_le16_to_cpu(c->limit);
 378         count = ext2fs_le16_to_cpu(c->count);
 379         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 380             fs->blocksize - sizeof(struct ext2_dx_tail))
 381                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 382         /* htree structs are accessed in LE order */
 383         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 384
 385         size = count_offset + (count * sizeof(struct ext2_dx_entry));
 386
 387         retval = ext2fs_read_inode(fs, inum, &inode);
 388         if (retval)
 389                 return retval;
 390
 391         inum = ext2fs_cpu_to_le32(inum);
 392         gen = ext2fs_cpu_to_le32(inode.i_generation);
 393         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 394                                 sizeof(inum));
 395         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 396         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 397         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)t, 4);
 398         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&dummy_csum, 4);
 399
 400         if (ret_t)
 401                 *ret_t = t;
 402         return 0;
 403 }
 404
 405 static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 406                                  struct ext2_dir_entry *dirent)
 407 {
 408         __u32 calculated;
 409         errcode_t retval;
 410         struct ext2_dx_tail *t;
 411
 412         retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, &t);
 413         if (retval)
 414                 return 0;
 415
 416         return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
 417 }
 418
 419 static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
 420                                     struct ext2_dir_entry *dirent)
 421 {
 422         __u32 crc;
 423         errcode_t retval = 0;
 424         struct ext2_dx_tail *t;
 425
 426         retval = ext2fs_dx_csum(fs, inum, dirent, &crc, &t);
 427         if (retval)
 428                 return retval;
 429         t->dt_checksum = ext2fs_cpu_to_le32(crc);
 430         return retval;
 431 }
 432
 433 int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 434                                  struct ext2_dir_entry *dirent)
 435 {
 436         if (!ext2fs_has_feature_metadata_csum(fs->super))
 437                 return 1;
 438
 439         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 440                 return ext2fs_dirent_csum_verify(fs, inum, dirent);
 441         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 442                 return ext2fs_dx_csum_verify(fs, inum, dirent);
 443
 444         return 0;
 445 }
 446
 447 errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 448                                     struct ext2_dir_entry *dirent)
 449 {
 450         if (!ext2fs_has_feature_metadata_csum(fs->super))
 451                 return 0;
 452
 453         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 454                 return ext2fs_dirent_csum_set(fs, inum, dirent);
 455         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 456                 return ext2fs_dx_csum_set(fs, inum, dirent);
 457
 458         if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
 459                 return 0;
 460         return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 461 }
 462
 463 #define EXT3_EXTENT_TAIL_OFFSET(hdr)    (sizeof(struct ext3_extent_header) + \
 464         (sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
 465
 466 static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
 467 {
 468         return (struct ext3_extent_tail *)(((char *)h) +
 469                                            EXT3_EXTENT_TAIL_OFFSET(h));
 470 }
 471
 472 static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
 473                                           struct ext3_extent_header *eh,
 474                                           __u32 *crc)
 475 {
 476         int size;
 477         __u32 gen;
 478         errcode_t retval;
 479         struct ext2_inode inode;
 480
 481         size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
 482                                                       et_checksum);
 483
 484         retval = ext2fs_read_inode(fs, inum, &inode);
 485         if (retval)
 486                 return retval;
 487         inum = ext2fs_cpu_to_le32(inum);
 488         gen = ext2fs_cpu_to_le32(inode.i_generation);
 489         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 490                                 sizeof(inum));
 491         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 492         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
 493
 494         return 0;
 495 }
 496
 497 int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 498                                     struct ext3_extent_header *eh)
 499 {
 500         errcode_t retval;
 501         __u32 provided, calculated;
 502         struct ext3_extent_tail *t = get_extent_tail(eh);
 503
 504         /*
 505          * The extent tree structures are accessed in LE order, so we must
 506          * swap the checksum bytes here.
 507          */
 508         if (!ext2fs_has_feature_metadata_csum(fs->super))
 509                 return 1;
 510
 511         provided = ext2fs_le32_to_cpu(t->et_checksum);
 512         retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
 513         if (retval)
 514                 return 0;
 515
 516         return provided == calculated;
 517 }
 518
 519 errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 520                                        struct ext3_extent_header *eh)
 521 {
 522         errcode_t retval;
 523         __u32 crc;
 524         struct ext3_extent_tail *t = get_extent_tail(eh);
 525
 526         if (!ext2fs_has_feature_metadata_csum(fs->super))
 527                 return 0;
 528
 529         /*
 530          * The extent tree structures are accessed in LE order, so we must
 531          * swap the checksum bytes here.
 532          */
 533         retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
 534         if (retval)
 535                 return retval;
 536         t->et_checksum = ext2fs_cpu_to_le32(crc);
 537         return retval;
 538 }
 539
 540 int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 541                                     char *bitmap, int size)
 542 {
 543         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 544                         ext2fs_group_desc(fs, fs->group_desc, group);
 545         __u32 provided, calculated;
 546
 547         if (!ext2fs_has_feature_metadata_csum(fs->super))
 548                 return 1;
 549         provided = gdp->bg_inode_bitmap_csum_lo;
 550         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 551                                       size);
 552         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 553                 provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
 554         else
 555                 calculated &= 0xFFFF;
 556
 557         return provided == calculated;
 558 }
 559
 560 errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 561                                        char *bitmap, int size)
 562 {
 563         __u32 crc;
 564         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 565                         ext2fs_group_desc(fs, fs->group_desc, group);
 566
 567         if (!ext2fs_has_feature_metadata_csum(fs->super))
 568                 return 0;
 569
 570         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 571         gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
 572         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 573                 gdp->bg_inode_bitmap_csum_hi = crc >> 16;
 574
 575         return 0;
 576 }
 577
 578 int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 579                                     char *bitmap, int size)
 580 {
 581         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 582                         ext2fs_group_desc(fs, fs->group_desc, group);
 583         __u32 provided, calculated;
 584
 585         if (!ext2fs_has_feature_metadata_csum(fs->super))
 586                 return 1;
 587         provided = gdp->bg_block_bitmap_csum_lo;
 588         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 589                                       size);
 590         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 591                 provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
 592         else
 593                 calculated &= 0xFFFF;
 594
 595         return provided == calculated;
 596 }
 597
 598 errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 599                                        char *bitmap, int size)
 600 {
 601         __u32 crc;
 602         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 603                         ext2fs_group_desc(fs, fs->group_desc, group);
 604
 605         if (!ext2fs_has_feature_metadata_csum(fs->super))
 606                 return 0;
 607
 608         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 609         gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
 610         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 611                 gdp->bg_block_bitmap_csum_hi = crc >> 16;
 612
 613         return 0;
 614 }
 615
 616 static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
 617                                struct ext2_inode_large *inode,
 618                                __u32 *crc, int has_hi)
 619 {
 620         __u32 gen;
 621         struct ext2_inode_large *desc = inode;
 622         size_t size = EXT2_INODE_SIZE(fs->super);
 623         __u16 old_lo;
 624         __u16 old_hi = 0;
 625
 626         old_lo = inode->i_checksum_lo;
 627         inode->i_checksum_lo = 0;
 628         if (has_hi) {
 629                 old_hi = inode->i_checksum_hi;
 630                 inode->i_checksum_hi = 0;
 631         }
 632
 633         inum = ext2fs_cpu_to_le32(inum);
 634         gen = inode->i_generation;
 635         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 636                                 sizeof(inum));
 637         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 638         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
 639
 640         inode->i_checksum_lo = old_lo;
 641         if (has_hi)
 642                 inode->i_checksum_hi = old_hi;
 643         return 0;
 644 }
 645
 646 int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 647                              struct ext2_inode_large *inode)
 648 {
 649         errcode_t retval;
 650         __u32 provided, calculated;
 651         unsigned int i, has_hi;
 652         char *cp;
 653
 654         if (!ext2fs_has_feature_metadata_csum(fs->super))
 655                 return 1;
 656
 657         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 658                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 659
 660         provided = ext2fs_le16_to_cpu(inode->i_checksum_lo);
 661         retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi);
 662         if (retval)
 663                 return 0;
 664         if (has_hi) {
 665                 __u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi);
 666                 provided |= hi << 16;
 667         } else
 668                 calculated &= 0xFFFF;
 669
 670         if (provided == calculated)
 671                 return 1;
 672
 673         /*
 674          * If the checksum didn't match, it's possible it was due to
 675          * the inode being all zero's.  It's unlikely this is the
 676          * case, but it can happen.  So check for it here.  (We only
 677          * check the base inode since that's good enough, and it's not
 678          * worth the bother to figure out how much of the extended
 679          * inode, if any, is present.)
 680          */
 681         for (cp = (char *) inode, i = 0;
 682              i < sizeof(struct ext2_inode);
 683              cp++, i++)
 684                 if (*cp)
 685                         return 0;
 686         return 1;               /* Inode must have been all zero's */
 687 }
 688
 689 errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
 690                            struct ext2_inode_large *inode)
 691 {
 692         errcode_t retval;
 693         __u32 crc;
 694         int has_hi;
 695
 696         if (!ext2fs_has_feature_metadata_csum(fs->super))
 697                 return 0;
 698
 699         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 700                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 701
 702         retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
 703         if (retval)
 704                 return retval;
 705         inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
 706         if (has_hi)
 707                 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
 708         return 0;
 709 }
 710
 711 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 712 {
 713         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 714                                                          group);
 715         size_t offset, size = EXT2_DESC_SIZE(fs->super);
 716         __u16 crc = 0;
 717 #ifdef WORDS_BIGENDIAN
 718         struct ext4_group_desc swabdesc;
 719         size_t save_size = size;
 720         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 721         struct ext2_group_desc *save_desc = desc;
 722
 723         /* Have to swab back to little-endian to do the checksum */
 724         if (size > ext4_bg_size)
 725                 size = ext4_bg_size;
 726         memcpy(&swabdesc, desc, size);
 727         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 728         desc = (struct ext2_group_desc *) &swabdesc;
 729         group = ext2fs_swab32(group);
 730 #endif
 731
 732         if (ext2fs_has_feature_metadata_csum(fs->super)) {
 733                 /* new metadata csum code */
 734                 __u16 old_crc;
 735                 __u32 crc32;
 736
 737                 old_crc = desc->bg_checksum;
 738                 desc->bg_checksum = 0;
 739                 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
 740                                          sizeof(group));
 741                 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
 742                                          size);
 743                 desc->bg_checksum = old_crc;
 744 #ifdef WORDS_BIGENDIAN
 745                 if (save_size > ext4_bg_size)
 746                         crc32 = ext2fs_crc32c_le(crc32,
 747                                      (unsigned char *)save_desc + ext4_bg_size,
 748                                      save_size - ext4_bg_size);
 749 #endif
 750                 crc = crc32 & 0xFFFF;
 751                 goto out;
 752         }
 753
 754         /* old crc16 code */
 755         offset = offsetof(struct ext2_group_desc, bg_checksum);
 756         crc = ext2fs_crc16(~0, fs->super->s_uuid,
 757                            sizeof(fs->super->s_uuid));
 758         crc = ext2fs_crc16(crc, &group, sizeof(group));
 759         crc = ext2fs_crc16(crc, desc, offset);
 760         offset += sizeof(desc->bg_checksum); /* skip checksum */
 761         /* for checksum of struct ext4_group_desc do the rest...*/
 762         if (offset < size) {
 763                 crc = ext2fs_crc16(crc, (char *)desc + offset,
 764                                    size - offset);
 765         }
 766 #ifdef WORDS_BIGENDIAN
 767         /*
 768          * If the size of the bg descriptor is greater than 64
 769          * bytes, which is the size of the traditional ext4 bg
 770          * descriptor, checksum the rest of the descriptor here
 771          */
 772         if (save_size > ext4_bg_size)
 773                 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
 774                                    save_size - ext4_bg_size);
 775 #endif
 776
 777 out:
 778         return crc;
 779 }
 780
 781 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
 782 {
 783         if (ext2fs_has_group_desc_csum(fs) &&
 784             (ext2fs_bg_checksum(fs, group) !=
 785              ext2fs_group_desc_csum(fs, group)))
 786                 return 0;
 787
 788         return 1;
 789 }
 790
 791 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
 792 {
 793         if (!ext2fs_has_group_desc_csum(fs))
 794                 return;
 795
 796         /* ext2fs_bg_checksum_set() sets the actual checksum field but
 797          * does not calculate the checksum itself. */
 798         ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
 799 }
 800
 801 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
 802                                    __u32 inodes_per_grp, dgrp_t grp_no)
 803 {
 804         ext2_ino_t i, start_ino, end_ino;
 805
 806         start_ino = grp_no * inodes_per_grp + 1;
 807         end_ino = start_ino + inodes_per_grp - 1;
 808
 809         for (i = end_ino; i >= start_ino; i--) {
 810                 if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
 811                         return i - start_ino + 1;
 812         }
 813         return inodes_per_grp;
 814 }
 815
 816 /* update the bitmap flags, set the itable high watermark, and calculate
 817  * checksums for the group descriptors */
 818 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
 819 {
 820         struct ext2_super_block *sb = fs->super;
 821         int dirty = 0;
 822         dgrp_t i;
 823
 824         if (!fs->inode_map)
 825                 return EXT2_ET_NO_INODE_BITMAP;
 826
 827         if (!ext2fs_has_group_desc_csum(fs))
 828                 return 0;
 829
 830         for (i = 0; i < fs->group_desc_count; i++) {
 831                 __u32 old_csum = ext2fs_bg_checksum(fs, i);
 832                 __u32 old_unused = ext2fs_bg_itable_unused(fs, i);
 833                 __u32 old_flags = ext2fs_bg_flags(fs, i);
 834                 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
 835                 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
 836
 837                 if (old_free_blocks_count == sb->s_blocks_per_group &&
 838                     i != fs->group_desc_count - 1)
 839                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 840
 841                 if (old_free_inodes_count == sb->s_inodes_per_group) {
 842                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 843                         ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
 844                 } else {
 845                         int unused =
 846                                 sb->s_inodes_per_group -
 847                                 find_last_inode_ingrp(fs->inode_map,
 848                                                       sb->s_inodes_per_group, i);
 849
 850                         ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
 851                         ext2fs_bg_itable_unused_set(fs, i, unused);
 852                 }
 853
 854                 ext2fs_group_desc_csum_set(fs, i);
 855                 if (old_flags != ext2fs_bg_flags(fs, i))
 856                         dirty = 1;
 857                 if (old_unused != ext2fs_bg_itable_unused(fs, i))
 858                         dirty = 1;
 859                 if (old_csum != ext2fs_bg_checksum(fs, i))
 860                         dirty = 1;
 861         }
 862         if (dirty)
 863                 ext2fs_mark_super_dirty(fs);
 864         return 0;
 865 }
 866
 867 #ifdef DEBUG
 868 #include "e2p/e2p.h"
 869
 870 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 871 {
 872         __u16 crc1, crc2, crc3;
 873         dgrp_t swabgroup;
 874         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 875                                                          group);
 876         size_t size = EXT2_DESC_SIZE(fs->super);
 877         struct ext2_super_block *sb = fs->super;
 878         int offset = offsetof(struct ext2_group_desc, bg_checksum);
 879 #ifdef WORDS_BIGENDIAN
 880         struct ext4_group_desc swabdesc;
 881         struct ext2_group_desc *save_desc = desc;
 882         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 883         size_t save_size = size;
 884 #endif
 885
 886 #ifdef WORDS_BIGENDIAN
 887         /* Have to swab back to little-endian to do the checksum */
 888         if (size > ext4_bg_size)
 889                 size = ext4_bg_size;
 890         memcpy(&swabdesc, desc, size);
 891         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 892         desc = (struct ext2_group_desc *) &swabdesc;
 893
 894         swabgroup = ext2fs_swab32(group);
 895 #else
 896         swabgroup = group;
 897 #endif
 898
 899         crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
 900         crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
 901         crc3 = ext2fs_crc16(crc2, desc, offset);
 902         offset += sizeof(desc->bg_checksum); /* skip checksum */
 903         /* for checksum of struct ext4_group_desc do the rest...*/
 904         if (offset < size)
 905                 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
 906 #ifdef WORDS_BIGENDIAN
 907         if (save_size > ext4_bg_size)
 908                 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
 909                                     save_size - ext4_bg_size);
 910 #endif
 911
 912         printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 913                msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 914                ext2fs_group_desc_csum(fs, group));
 915 }
 916
 917 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
 918                               0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
 919
 920 int main(int argc, char **argv)
 921 {
 922         struct ext2_super_block param;
 923         errcode_t               retval;
 924         ext2_filsys             fs;
 925         int                     i;
 926         __u16 csum1, csum2, csum_known = 0xd3a4;
 927
 928         memset(&param, 0, sizeof(param));
 929         ext2fs_blocks_count_set(&param, 32768);
 930 #if 0
 931         param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 932         param.s_desc_size = 128;
 933         csum_known = 0x5b6e;
 934 #endif
 935
 936         retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 937                                    test_io_manager, &fs);
 938         if (retval) {
 939                 com_err("setup", retval,
 940                         "While initializing filesystem");
 941                 exit(1);
 942         }
 943         memcpy(fs->super->s_uuid, sb_uuid, 16);
 944         fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 945
 946         for (i=0; i < fs->group_desc_count; i++) {
 947                 ext2fs_block_bitmap_loc_set(fs, i, 124);
 948                 ext2fs_inode_bitmap_loc_set(fs, i, 125);
 949                 ext2fs_inode_table_loc_set(fs, i, 126);
 950                 ext2fs_bg_free_blocks_count_set(fs, i, 31119);
 951                 ext2fs_bg_free_inodes_count_set(fs, i, 15701);
 952                 ext2fs_bg_used_dirs_count_set(fs, i, 2);
 953                 ext2fs_bg_flags_zap(fs, i);
 954         };
 955
 956         csum1 = ext2fs_group_desc_csum(fs, 0);
 957         print_csum("csum0000", fs, 0);
 958
 959         if (csum1 != csum_known) {
 960                 printf("checksum for group 0 should be %04x\n", csum_known);
 961                 exit(1);
 962         }
 963         csum2 = ext2fs_group_desc_csum(fs, 1);
 964         print_csum("csum0001", fs, 1);
 965         if (csum1 == csum2) {
 966                 printf("checksums for different groups shouldn't match\n");
 967                 exit(1);
 968         }
 969         csum2 = ext2fs_group_desc_csum(fs, 2);
 970         print_csum("csumffff", fs, 2);
 971         if (csum1 == csum2) {
 972                 printf("checksums for different groups shouldn't match\n");
 973                 exit(1);
 974         }
 975         ext2fs_bg_checksum_set(fs, 0, csum1);
 976         csum2 = ext2fs_group_desc_csum(fs, 0);
 977         print_csum("csum_set", fs, 0);
 978         if (csum1 != csum2) {
 979                 printf("checksums should not depend on checksum field\n");
 980                 exit(1);
 981         }
 982         if (!ext2fs_group_desc_csum_verify(fs, 0)) {
 983                 printf("checksums should verify against gd_checksum\n");
 984                 exit(1);
 985         }
 986         memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
 987         print_csum("new_uuid", fs, 0);
 988         if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
 989                 printf("checksums for different filesystems shouldn't match\n");
 990                 exit(1);
 991         }
 992         csum1 = ext2fs_group_desc_csum(fs, 0);
 993         ext2fs_bg_checksum_set(fs, 0, csum1);
 994         print_csum("csum_new", fs, 0);
 995         ext2fs_bg_free_blocks_count_set(fs, 0, 1);
 996         csum2 = ext2fs_group_desc_csum(fs, 0);
 997         print_csum("csum_blk", fs, 0);
 998         if (csum1 == csum2) {
 999                 printf("checksums for different data shouldn't match\n");
1000                 exit(1);
1001         }
1002         ext2fs_free(fs);
1003
1004         return 0;
1005 }
1006 #endif