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 static errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
 362                                 struct ext2_dir_entry *dirent,
 363                                 __u32 *crc, int count_offset, int count,
 364                                 struct ext2_dx_tail *t)
 365 {
 366         errcode_t retval;
 367         char *buf = (char *)dirent;
 368         int size;
 369         __u32 old_csum, gen;
 370         struct ext2_inode inode;
 371
 372         size = count_offset + (count * sizeof(struct ext2_dx_entry));
 373         old_csum = t->dt_checksum;
 374         t->dt_checksum = 0;
 375
 376         retval = ext2fs_read_inode(fs, inum, &inode);
 377         if (retval)
 378                 return retval;
 379
 380         inum = ext2fs_cpu_to_le32(inum);
 381         gen = ext2fs_cpu_to_le32(inode.i_generation);
 382         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 383                                 sizeof(inum));
 384         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 385         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 386         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)t,
 387                                 sizeof(struct ext2_dx_tail));
 388         t->dt_checksum = old_csum;
 389
 390         return 0;
 391 }
 392
 393 static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 394                                  struct ext2_dir_entry *dirent)
 395 {
 396         __u32 calculated;
 397         errcode_t retval;
 398         struct ext2_dx_countlimit *c;
 399         struct ext2_dx_tail *t;
 400         int count_offset, limit, count;
 401
 402         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 403         if (retval)
 404                 return 1;
 405         limit = ext2fs_le16_to_cpu(c->limit);
 406         count = ext2fs_le16_to_cpu(c->count);
 407         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 408             fs->blocksize - sizeof(struct ext2_dx_tail))
 409                 return 0;
 410         /* htree structs are accessed in LE order */
 411         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 412         retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, count_offset,
 413                                 count, t);
 414         if (retval)
 415                 return 0;
 416
 417         return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
 418 }
 419
 420 static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
 421                                     struct ext2_dir_entry *dirent)
 422 {
 423         __u32 crc;
 424         errcode_t retval = 0;
 425         struct ext2_dx_countlimit *c;
 426         struct ext2_dx_tail *t;
 427         int count_offset, limit, count;
 428
 429         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 430         if (retval)
 431                 return retval;
 432         limit = ext2fs_le16_to_cpu(c->limit);
 433         count = ext2fs_le16_to_cpu(c->count);
 434         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 435             fs->blocksize - sizeof(struct ext2_dx_tail))
 436                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 437         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 438
 439         /* htree structs are accessed in LE order */
 440         retval = ext2fs_dx_csum(fs, inum, dirent, &crc, count_offset, count, t);
 441         if (retval)
 442                 return retval;
 443         t->dt_checksum = ext2fs_cpu_to_le32(crc);
 444         return retval;
 445 }
 446
 447 int ext2fs_dir_block_csum_verify(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 1;
 452
 453         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 454                 return ext2fs_dirent_csum_verify(fs, inum, dirent);
 455         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 456                 return ext2fs_dx_csum_verify(fs, inum, dirent);
 457
 458         return 0;
 459 }
 460
 461 errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 462                                     struct ext2_dir_entry *dirent)
 463 {
 464         if (!ext2fs_has_feature_metadata_csum(fs->super))
 465                 return 0;
 466
 467         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 468                 return ext2fs_dirent_csum_set(fs, inum, dirent);
 469         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 470                 return ext2fs_dx_csum_set(fs, inum, dirent);
 471
 472         if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
 473                 return 0;
 474         return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 475 }
 476
 477 #define EXT3_EXTENT_TAIL_OFFSET(hdr)    (sizeof(struct ext3_extent_header) + \
 478         (sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
 479
 480 static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
 481 {
 482         return (struct ext3_extent_tail *)(((char *)h) +
 483                                            EXT3_EXTENT_TAIL_OFFSET(h));
 484 }
 485
 486 static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
 487                                           struct ext3_extent_header *eh,
 488                                           __u32 *crc)
 489 {
 490         int size;
 491         __u32 gen;
 492         errcode_t retval;
 493         struct ext2_inode inode;
 494
 495         size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
 496                                                       et_checksum);
 497
 498         retval = ext2fs_read_inode(fs, inum, &inode);
 499         if (retval)
 500                 return retval;
 501         inum = ext2fs_cpu_to_le32(inum);
 502         gen = ext2fs_cpu_to_le32(inode.i_generation);
 503         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 504                                 sizeof(inum));
 505         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 506         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
 507
 508         return 0;
 509 }
 510
 511 int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 512                                     struct ext3_extent_header *eh)
 513 {
 514         errcode_t retval;
 515         __u32 provided, calculated;
 516         struct ext3_extent_tail *t = get_extent_tail(eh);
 517
 518         /*
 519          * The extent tree structures are accessed in LE order, so we must
 520          * swap the checksum bytes here.
 521          */
 522         if (!ext2fs_has_feature_metadata_csum(fs->super))
 523                 return 1;
 524
 525         provided = ext2fs_le32_to_cpu(t->et_checksum);
 526         retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
 527         if (retval)
 528                 return 0;
 529
 530         return provided == calculated;
 531 }
 532
 533 errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 534                                        struct ext3_extent_header *eh)
 535 {
 536         errcode_t retval;
 537         __u32 crc;
 538         struct ext3_extent_tail *t = get_extent_tail(eh);
 539
 540         if (!ext2fs_has_feature_metadata_csum(fs->super))
 541                 return 0;
 542
 543         /*
 544          * The extent tree structures are accessed in LE order, so we must
 545          * swap the checksum bytes here.
 546          */
 547         retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
 548         if (retval)
 549                 return retval;
 550         t->et_checksum = ext2fs_cpu_to_le32(crc);
 551         return retval;
 552 }
 553
 554 int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 555                                     char *bitmap, int size)
 556 {
 557         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 558                         ext2fs_group_desc(fs, fs->group_desc, group);
 559         __u32 provided, calculated;
 560
 561         if (!ext2fs_has_feature_metadata_csum(fs->super))
 562                 return 1;
 563         provided = gdp->bg_inode_bitmap_csum_lo;
 564         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 565                                       size);
 566         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 567                 provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
 568         else
 569                 calculated &= 0xFFFF;
 570
 571         return provided == calculated;
 572 }
 573
 574 errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 575                                        char *bitmap, int size)
 576 {
 577         __u32 crc;
 578         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 579                         ext2fs_group_desc(fs, fs->group_desc, group);
 580
 581         if (!ext2fs_has_feature_metadata_csum(fs->super))
 582                 return 0;
 583
 584         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 585         gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
 586         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 587                 gdp->bg_inode_bitmap_csum_hi = crc >> 16;
 588
 589         return 0;
 590 }
 591
 592 int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 593                                     char *bitmap, int size)
 594 {
 595         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 596                         ext2fs_group_desc(fs, fs->group_desc, group);
 597         __u32 provided, calculated;
 598
 599         if (!ext2fs_has_feature_metadata_csum(fs->super))
 600                 return 1;
 601         provided = gdp->bg_block_bitmap_csum_lo;
 602         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 603                                       size);
 604         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 605                 provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
 606         else
 607                 calculated &= 0xFFFF;
 608
 609         return provided == calculated;
 610 }
 611
 612 errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 613                                        char *bitmap, int size)
 614 {
 615         __u32 crc;
 616         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 617                         ext2fs_group_desc(fs, fs->group_desc, group);
 618
 619         if (!ext2fs_has_feature_metadata_csum(fs->super))
 620                 return 0;
 621
 622         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 623         gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
 624         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 625                 gdp->bg_block_bitmap_csum_hi = crc >> 16;
 626
 627         return 0;
 628 }
 629
 630 static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
 631                                struct ext2_inode_large *inode,
 632                                __u32 *crc, int has_hi)
 633 {
 634         __u32 gen;
 635         struct ext2_inode_large *desc = inode;
 636         size_t size = EXT2_INODE_SIZE(fs->super);
 637         __u16 old_lo;
 638         __u16 old_hi = 0;
 639
 640         old_lo = inode->i_checksum_lo;
 641         inode->i_checksum_lo = 0;
 642         if (has_hi) {
 643                 old_hi = inode->i_checksum_hi;
 644                 inode->i_checksum_hi = 0;
 645         }
 646
 647         inum = ext2fs_cpu_to_le32(inum);
 648         gen = inode->i_generation;
 649         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 650                                 sizeof(inum));
 651         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 652         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
 653
 654         inode->i_checksum_lo = old_lo;
 655         if (has_hi)
 656                 inode->i_checksum_hi = old_hi;
 657         return 0;
 658 }
 659
 660 int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 661                              struct ext2_inode_large *inode)
 662 {
 663         errcode_t retval;
 664         __u32 provided, calculated;
 665         unsigned int i, has_hi;
 666         char *cp;
 667
 668         if (!ext2fs_has_feature_metadata_csum(fs->super))
 669                 return 1;
 670
 671         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 672                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 673
 674         provided = ext2fs_le16_to_cpu(inode->i_checksum_lo);
 675         retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi);
 676         if (retval)
 677                 return 0;
 678         if (has_hi) {
 679                 __u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi);
 680                 provided |= hi << 16;
 681         } else
 682                 calculated &= 0xFFFF;
 683
 684         if (provided == calculated)
 685                 return 1;
 686
 687         /*
 688          * If the checksum didn't match, it's possible it was due to
 689          * the inode being all zero's.  It's unlikely this is the
 690          * case, but it can happen.  So check for it here.  (We only
 691          * check the base inode since that's good enough, and it's not
 692          * worth the bother to figure out how much of the extended
 693          * inode, if any, is present.)
 694          */
 695         for (cp = (char *) inode, i = 0;
 696              i < sizeof(struct ext2_inode);
 697              cp++, i++)
 698                 if (*cp)
 699                         return 0;
 700         return 1;               /* Inode must have been all zero's */
 701 }
 702
 703 errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
 704                            struct ext2_inode_large *inode)
 705 {
 706         errcode_t retval;
 707         __u32 crc;
 708         int has_hi;
 709
 710         if (!ext2fs_has_feature_metadata_csum(fs->super))
 711                 return 0;
 712
 713         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 714                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 715
 716         retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
 717         if (retval)
 718                 return retval;
 719         inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
 720         if (has_hi)
 721                 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
 722         return 0;
 723 }
 724
 725 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 726 {
 727         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 728                                                          group);
 729         size_t offset, size = EXT2_DESC_SIZE(fs->super);
 730         __u16 crc = 0;
 731 #ifdef WORDS_BIGENDIAN
 732         struct ext4_group_desc swabdesc;
 733         size_t save_size = size;
 734         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 735         struct ext2_group_desc *save_desc = desc;
 736
 737         /* Have to swab back to little-endian to do the checksum */
 738         if (size > ext4_bg_size)
 739                 size = ext4_bg_size;
 740         memcpy(&swabdesc, desc, size);
 741         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 742         desc = (struct ext2_group_desc *) &swabdesc;
 743         group = ext2fs_swab32(group);
 744 #endif
 745
 746         if (ext2fs_has_feature_metadata_csum(fs->super)) {
 747                 /* new metadata csum code */
 748                 __u16 old_crc;
 749                 __u32 crc32;
 750
 751                 old_crc = desc->bg_checksum;
 752                 desc->bg_checksum = 0;
 753                 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
 754                                          sizeof(group));
 755                 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
 756                                          size);
 757                 desc->bg_checksum = old_crc;
 758 #ifdef WORDS_BIGENDIAN
 759                 if (save_size > ext4_bg_size)
 760                         crc32 = ext2fs_crc32c_le(crc32,
 761                                      (unsigned char *)save_desc + ext4_bg_size,
 762                                      save_size - ext4_bg_size);
 763 #endif
 764                 crc = crc32 & 0xFFFF;
 765                 goto out;
 766         }
 767
 768         /* old crc16 code */
 769         offset = offsetof(struct ext2_group_desc, bg_checksum);
 770         crc = ext2fs_crc16(~0, fs->super->s_uuid,
 771                            sizeof(fs->super->s_uuid));
 772         crc = ext2fs_crc16(crc, &group, sizeof(group));
 773         crc = ext2fs_crc16(crc, desc, offset);
 774         offset += sizeof(desc->bg_checksum); /* skip checksum */
 775         /* for checksum of struct ext4_group_desc do the rest...*/
 776         if (offset < size) {
 777                 crc = ext2fs_crc16(crc, (char *)desc + offset,
 778                                    size - offset);
 779         }
 780 #ifdef WORDS_BIGENDIAN
 781         /*
 782          * If the size of the bg descriptor is greater than 64
 783          * bytes, which is the size of the traditional ext4 bg
 784          * descriptor, checksum the rest of the descriptor here
 785          */
 786         if (save_size > ext4_bg_size)
 787                 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
 788                                    save_size - ext4_bg_size);
 789 #endif
 790
 791 out:
 792         return crc;
 793 }
 794
 795 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
 796 {
 797         if (ext2fs_has_group_desc_csum(fs) &&
 798             (ext2fs_bg_checksum(fs, group) !=
 799              ext2fs_group_desc_csum(fs, group)))
 800                 return 0;
 801
 802         return 1;
 803 }
 804
 805 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
 806 {
 807         if (!ext2fs_has_group_desc_csum(fs))
 808                 return;
 809
 810         /* ext2fs_bg_checksum_set() sets the actual checksum field but
 811          * does not calculate the checksum itself. */
 812         ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
 813 }
 814
 815 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
 816                                    __u32 inodes_per_grp, dgrp_t grp_no)
 817 {
 818         ext2_ino_t i, start_ino, end_ino;
 819
 820         start_ino = grp_no * inodes_per_grp + 1;
 821         end_ino = start_ino + inodes_per_grp - 1;
 822
 823         for (i = end_ino; i >= start_ino; i--) {
 824                 if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
 825                         return i - start_ino + 1;
 826         }
 827         return inodes_per_grp;
 828 }
 829
 830 /* update the bitmap flags, set the itable high watermark, and calculate
 831  * checksums for the group descriptors */
 832 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
 833 {
 834         struct ext2_super_block *sb = fs->super;
 835         int dirty = 0;
 836         dgrp_t i;
 837
 838         if (!fs->inode_map)
 839                 return EXT2_ET_NO_INODE_BITMAP;
 840
 841         if (!ext2fs_has_group_desc_csum(fs))
 842                 return 0;
 843
 844         for (i = 0; i < fs->group_desc_count; i++) {
 845                 __u32 old_csum = ext2fs_bg_checksum(fs, i);
 846                 __u32 old_unused = ext2fs_bg_itable_unused(fs, i);
 847                 __u32 old_flags = ext2fs_bg_flags(fs, i);
 848                 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
 849                 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
 850
 851                 if (old_free_blocks_count == sb->s_blocks_per_group &&
 852                     i != fs->group_desc_count - 1)
 853                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 854
 855                 if (old_free_inodes_count == sb->s_inodes_per_group) {
 856                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 857                         ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
 858                 } else {
 859                         int unused =
 860                                 sb->s_inodes_per_group -
 861                                 find_last_inode_ingrp(fs->inode_map,
 862                                                       sb->s_inodes_per_group, i);
 863
 864                         ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
 865                         ext2fs_bg_itable_unused_set(fs, i, unused);
 866                 }
 867
 868                 ext2fs_group_desc_csum_set(fs, i);
 869                 if (old_flags != ext2fs_bg_flags(fs, i))
 870                         dirty = 1;
 871                 if (old_unused != ext2fs_bg_itable_unused(fs, i))
 872                         dirty = 1;
 873                 if (old_csum != ext2fs_bg_checksum(fs, i))
 874                         dirty = 1;
 875         }
 876         if (dirty)
 877                 ext2fs_mark_super_dirty(fs);
 878         return 0;
 879 }
 880
 881 #ifdef DEBUG
 882 #include "e2p/e2p.h"
 883
 884 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 885 {
 886         __u16 crc1, crc2, crc3;
 887         dgrp_t swabgroup;
 888         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 889                                                          group);
 890         size_t size = EXT2_DESC_SIZE(fs->super);
 891         struct ext2_super_block *sb = fs->super;
 892         int offset = offsetof(struct ext2_group_desc, bg_checksum);
 893 #ifdef WORDS_BIGENDIAN
 894         struct ext4_group_desc swabdesc;
 895         struct ext2_group_desc *save_desc = desc;
 896         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 897         size_t save_size = size;
 898 #endif
 899
 900 #ifdef WORDS_BIGENDIAN
 901         /* Have to swab back to little-endian to do the checksum */
 902         if (size > ext4_bg_size)
 903                 size = ext4_bg_size;
 904         memcpy(&swabdesc, desc, size);
 905         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 906         desc = (struct ext2_group_desc *) &swabdesc;
 907
 908         swabgroup = ext2fs_swab32(group);
 909 #else
 910         swabgroup = group;
 911 #endif
 912
 913         crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
 914         crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
 915         crc3 = ext2fs_crc16(crc2, desc, offset);
 916         offset += sizeof(desc->bg_checksum); /* skip checksum */
 917         /* for checksum of struct ext4_group_desc do the rest...*/
 918         if (offset < size)
 919                 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
 920 #ifdef WORDS_BIGENDIAN
 921         if (save_size > ext4_bg_size)
 922                 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
 923                                     save_size - ext4_bg_size);
 924 #endif
 925
 926         printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 927                msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 928                ext2fs_group_desc_csum(fs, group));
 929 }
 930
 931 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
 932                               0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
 933
 934 int main(int argc, char **argv)
 935 {
 936         struct ext2_super_block param;
 937         errcode_t               retval;
 938         ext2_filsys             fs;
 939         int                     i;
 940         __u16 csum1, csum2, csum_known = 0xd3a4;
 941
 942         memset(&param, 0, sizeof(param));
 943         ext2fs_blocks_count_set(&param, 32768);
 944 #if 0
 945         param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 946         param.s_desc_size = 128;
 947         csum_known = 0x5b6e;
 948 #endif
 949
 950         retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 951                                    test_io_manager, &fs);
 952         if (retval) {
 953                 com_err("setup", retval,
 954                         "While initializing filesystem");
 955                 exit(1);
 956         }
 957         memcpy(fs->super->s_uuid, sb_uuid, 16);
 958         fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 959
 960         for (i=0; i < fs->group_desc_count; i++) {
 961                 ext2fs_block_bitmap_loc_set(fs, i, 124);
 962                 ext2fs_inode_bitmap_loc_set(fs, i, 125);
 963                 ext2fs_inode_table_loc_set(fs, i, 126);
 964                 ext2fs_bg_free_blocks_count_set(fs, i, 31119);
 965                 ext2fs_bg_free_inodes_count_set(fs, i, 15701);
 966                 ext2fs_bg_used_dirs_count_set(fs, i, 2);
 967                 ext2fs_bg_flags_zap(fs, i);
 968         };
 969
 970         csum1 = ext2fs_group_desc_csum(fs, 0);
 971         print_csum("csum0000", fs, 0);
 972
 973         if (csum1 != csum_known) {
 974                 printf("checksum for group 0 should be %04x\n", csum_known);
 975                 exit(1);
 976         }
 977         csum2 = ext2fs_group_desc_csum(fs, 1);
 978         print_csum("csum0001", fs, 1);
 979         if (csum1 == csum2) {
 980                 printf("checksums for different groups shouldn't match\n");
 981                 exit(1);
 982         }
 983         csum2 = ext2fs_group_desc_csum(fs, 2);
 984         print_csum("csumffff", fs, 2);
 985         if (csum1 == csum2) {
 986                 printf("checksums for different groups shouldn't match\n");
 987                 exit(1);
 988         }
 989         ext2fs_bg_checksum_set(fs, 0, csum1);
 990         csum2 = ext2fs_group_desc_csum(fs, 0);
 991         print_csum("csum_set", fs, 0);
 992         if (csum1 != csum2) {
 993                 printf("checksums should not depend on checksum field\n");
 994                 exit(1);
 995         }
 996         if (!ext2fs_group_desc_csum_verify(fs, 0)) {
 997                 printf("checksums should verify against gd_checksum\n");
 998                 exit(1);
 999         }
1000         memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
1001         print_csum("new_uuid", fs, 0);
1002         if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
1003                 printf("checksums for different filesystems shouldn't match\n");
1004                 exit(1);
1005         }
1006         csum1 = ext2fs_group_desc_csum(fs, 0);
1007         ext2fs_bg_checksum_set(fs, 0, csum1);
1008         print_csum("csum_new", fs, 0);
1009         ext2fs_bg_free_blocks_count_set(fs, 0, 1);
1010         csum2 = ext2fs_group_desc_csum(fs, 0);
1011         print_csum("csum_blk", fs, 0);
1012         if (csum1 == csum2) {
1013                 printf("checksums for different data shouldn't match\n");
1014                 exit(1);
1015         }
1016         ext2fs_free(fs);
1017
1018         return 0;
1019 }
1020 #endif