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 ((void *) d < top) {
 271                 if ((rec_len < 8) || (rec_len & 0x03))
 272                         return EXT2_ET_DIR_CORRUPTED;
 273                 d = (struct ext2_dir_entry *)(((char *)d) + rec_len);
 274                 rec_len = translate(d->rec_len);
 275         }
 276
 277         if ((char *)d > ((char *)dirent + fs->blocksize))
 278                         return EXT2_ET_DIR_CORRUPTED;
 279         if (d != top)
 280                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 281
 282         t = (struct ext2_dir_entry_tail *)d;
 283         if (t->det_reserved_zero1 ||
 284             translate(t->det_rec_len) != sizeof(struct ext2_dir_entry_tail) ||
 285             translate(t->det_reserved_name_len) != EXT2_DIR_NAME_LEN_CSUM)
 286                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 287
 288         if (tt)
 289                 *tt = t;
 290         return retval;
 291 }
 292
 293 int ext2fs_dirent_has_tail(ext2_filsys fs, struct ext2_dir_entry *dirent)
 294 {
 295         return __get_dirent_tail(fs, dirent, NULL, 0) !=
 296                 EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 297 }
 298
 299 static errcode_t ext2fs_dirent_csum(ext2_filsys fs, ext2_ino_t inum,
 300                                     struct ext2_dir_entry *dirent, __u32 *crc,
 301                                     int size)
 302 {
 303         errcode_t retval;
 304         char *buf = (char *)dirent;
 305         __u32 gen;
 306         struct ext2_inode inode;
 307
 308         retval = ext2fs_read_inode(fs, inum, &inode);
 309         if (retval)
 310                 return retval;
 311
 312         inum = ext2fs_cpu_to_le32(inum);
 313         gen = ext2fs_cpu_to_le32(inode.i_generation);
 314         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 315                                 sizeof(inum));
 316         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 317         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 318
 319         return 0;
 320 }
 321
 322 int ext2fs_dirent_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 323                               struct ext2_dir_entry *dirent)
 324 {
 325         errcode_t retval;
 326         __u32 calculated;
 327         struct ext2_dir_entry_tail *t;
 328
 329         retval = __get_dirent_tail(fs, dirent, &t, 1);
 330         if (retval)
 331                 return 1;
 332
 333         /*
 334          * The checksum field is overlaid with the dirent->name field
 335          * so the swapfs.c functions won't change the endianness.
 336          */
 337         retval = ext2fs_dirent_csum(fs, inum, dirent, &calculated,
 338                                     (char *)t - (char *)dirent);
 339         if (retval)
 340                 return 0;
 341         return ext2fs_le32_to_cpu(t->det_checksum) == calculated;
 342 }
 343
 344 static errcode_t ext2fs_dirent_csum_set(ext2_filsys fs, ext2_ino_t inum,
 345                                         struct ext2_dir_entry *dirent)
 346 {
 347         errcode_t retval;
 348         __u32 crc;
 349         struct ext2_dir_entry_tail *t;
 350
 351         retval = __get_dirent_tail(fs, dirent, &t, 1);
 352         if (retval)
 353                 return retval;
 354
 355         /* swapfs.c functions don't change the checksum endianness */
 356         retval = ext2fs_dirent_csum(fs, inum, dirent, &crc,
 357                                     (char *)t - (char *)dirent);
 358         if (retval)
 359                 return retval;
 360         t->det_checksum = ext2fs_cpu_to_le32(crc);
 361         return 0;
 362 }
 363
 364 static errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
 365                                 struct ext2_dir_entry *dirent,
 366                                 __u32 *crc, int count_offset, int count,
 367                                 struct ext2_dx_tail *t)
 368 {
 369         errcode_t retval;
 370         char *buf = (char *)dirent;
 371         int size;
 372         __u32 old_csum, gen;
 373         struct ext2_inode inode;
 374
 375         size = count_offset + (count * sizeof(struct ext2_dx_entry));
 376         old_csum = t->dt_checksum;
 377         t->dt_checksum = 0;
 378
 379         retval = ext2fs_read_inode(fs, inum, &inode);
 380         if (retval)
 381                 return retval;
 382
 383         inum = ext2fs_cpu_to_le32(inum);
 384         gen = ext2fs_cpu_to_le32(inode.i_generation);
 385         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 386                                 sizeof(inum));
 387         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 388         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 389         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)t,
 390                                 sizeof(struct ext2_dx_tail));
 391         t->dt_checksum = old_csum;
 392
 393         return 0;
 394 }
 395
 396 static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 397                                  struct ext2_dir_entry *dirent)
 398 {
 399         __u32 calculated;
 400         errcode_t retval;
 401         struct ext2_dx_countlimit *c;
 402         struct ext2_dx_tail *t;
 403         int count_offset, limit, count;
 404
 405         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 406         if (retval)
 407                 return 1;
 408         limit = ext2fs_le16_to_cpu(c->limit);
 409         count = ext2fs_le16_to_cpu(c->count);
 410         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 411             fs->blocksize - sizeof(struct ext2_dx_tail))
 412                 return 0;
 413         /* htree structs are accessed in LE order */
 414         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 415         retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, count_offset,
 416                                 count, t);
 417         if (retval)
 418                 return 0;
 419
 420         return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
 421 }
 422
 423 static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
 424                                     struct ext2_dir_entry *dirent)
 425 {
 426         __u32 crc;
 427         errcode_t retval = 0;
 428         struct ext2_dx_countlimit *c;
 429         struct ext2_dx_tail *t;
 430         int count_offset, limit, count;
 431
 432         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 433         if (retval)
 434                 return retval;
 435         limit = ext2fs_le16_to_cpu(c->limit);
 436         count = ext2fs_le16_to_cpu(c->count);
 437         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 438             fs->blocksize - sizeof(struct ext2_dx_tail))
 439                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 440         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 441
 442         /* htree structs are accessed in LE order */
 443         retval = ext2fs_dx_csum(fs, inum, dirent, &crc, count_offset, count, t);
 444         if (retval)
 445                 return retval;
 446         t->dt_checksum = ext2fs_cpu_to_le32(crc);
 447         return retval;
 448 }
 449
 450 int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 451                                  struct ext2_dir_entry *dirent)
 452 {
 453         if (!ext2fs_has_feature_metadata_csum(fs->super))
 454                 return 1;
 455
 456         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 457                 return ext2fs_dirent_csum_verify(fs, inum, dirent);
 458         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 459                 return ext2fs_dx_csum_verify(fs, inum, dirent);
 460
 461         return 0;
 462 }
 463
 464 errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 465                                     struct ext2_dir_entry *dirent)
 466 {
 467         if (!ext2fs_has_feature_metadata_csum(fs->super))
 468                 return 0;
 469
 470         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 471                 return ext2fs_dirent_csum_set(fs, inum, dirent);
 472         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 473                 return ext2fs_dx_csum_set(fs, inum, dirent);
 474
 475         if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
 476                 return 0;
 477         return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 478 }
 479
 480 #define EXT3_EXTENT_TAIL_OFFSET(hdr)    (sizeof(struct ext3_extent_header) + \
 481         (sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
 482
 483 static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
 484 {
 485         return (struct ext3_extent_tail *)(((char *)h) +
 486                                            EXT3_EXTENT_TAIL_OFFSET(h));
 487 }
 488
 489 static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
 490                                           struct ext3_extent_header *eh,
 491                                           __u32 *crc)
 492 {
 493         int size;
 494         __u32 gen;
 495         errcode_t retval;
 496         struct ext2_inode inode;
 497
 498         size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
 499                                                       et_checksum);
 500
 501         retval = ext2fs_read_inode(fs, inum, &inode);
 502         if (retval)
 503                 return retval;
 504         inum = ext2fs_cpu_to_le32(inum);
 505         gen = ext2fs_cpu_to_le32(inode.i_generation);
 506         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 507                                 sizeof(inum));
 508         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 509         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
 510
 511         return 0;
 512 }
 513
 514 int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 515                                     struct ext3_extent_header *eh)
 516 {
 517         errcode_t retval;
 518         __u32 provided, calculated;
 519         struct ext3_extent_tail *t = get_extent_tail(eh);
 520
 521         /*
 522          * The extent tree structures are accessed in LE order, so we must
 523          * swap the checksum bytes here.
 524          */
 525         if (!ext2fs_has_feature_metadata_csum(fs->super))
 526                 return 1;
 527
 528         provided = ext2fs_le32_to_cpu(t->et_checksum);
 529         retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
 530         if (retval)
 531                 return 0;
 532
 533         return provided == calculated;
 534 }
 535
 536 errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 537                                        struct ext3_extent_header *eh)
 538 {
 539         errcode_t retval;
 540         __u32 crc;
 541         struct ext3_extent_tail *t = get_extent_tail(eh);
 542
 543         if (!ext2fs_has_feature_metadata_csum(fs->super))
 544                 return 0;
 545
 546         /*
 547          * The extent tree structures are accessed in LE order, so we must
 548          * swap the checksum bytes here.
 549          */
 550         retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
 551         if (retval)
 552                 return retval;
 553         t->et_checksum = ext2fs_cpu_to_le32(crc);
 554         return retval;
 555 }
 556
 557 int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 558                                     char *bitmap, int size)
 559 {
 560         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 561                         ext2fs_group_desc(fs, fs->group_desc, group);
 562         __u32 provided, calculated;
 563
 564         if (!ext2fs_has_feature_metadata_csum(fs->super))
 565                 return 1;
 566         provided = gdp->bg_inode_bitmap_csum_lo;
 567         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 568                                       size);
 569         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 570                 provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
 571         else
 572                 calculated &= 0xFFFF;
 573
 574         return provided == calculated;
 575 }
 576
 577 errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 578                                        char *bitmap, int size)
 579 {
 580         __u32 crc;
 581         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 582                         ext2fs_group_desc(fs, fs->group_desc, group);
 583
 584         if (!ext2fs_has_feature_metadata_csum(fs->super))
 585                 return 0;
 586
 587         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 588         gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
 589         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 590                 gdp->bg_inode_bitmap_csum_hi = crc >> 16;
 591
 592         return 0;
 593 }
 594
 595 int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 596                                     char *bitmap, int size)
 597 {
 598         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 599                         ext2fs_group_desc(fs, fs->group_desc, group);
 600         __u32 provided, calculated;
 601
 602         if (!ext2fs_has_feature_metadata_csum(fs->super))
 603                 return 1;
 604         provided = gdp->bg_block_bitmap_csum_lo;
 605         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 606                                       size);
 607         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 608                 provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
 609         else
 610                 calculated &= 0xFFFF;
 611
 612         return provided == calculated;
 613 }
 614
 615 errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 616                                        char *bitmap, int size)
 617 {
 618         __u32 crc;
 619         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 620                         ext2fs_group_desc(fs, fs->group_desc, group);
 621
 622         if (!ext2fs_has_feature_metadata_csum(fs->super))
 623                 return 0;
 624
 625         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 626         gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
 627         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 628                 gdp->bg_block_bitmap_csum_hi = crc >> 16;
 629
 630         return 0;
 631 }
 632
 633 static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
 634                                struct ext2_inode_large *inode,
 635                                __u32 *crc, int has_hi)
 636 {
 637         __u32 gen;
 638         struct ext2_inode_large *desc = inode;
 639         size_t size = EXT2_INODE_SIZE(fs->super);
 640         __u16 old_lo;
 641         __u16 old_hi = 0;
 642
 643         old_lo = inode->i_checksum_lo;
 644         inode->i_checksum_lo = 0;
 645         if (has_hi) {
 646                 old_hi = inode->i_checksum_hi;
 647                 inode->i_checksum_hi = 0;
 648         }
 649
 650         inum = ext2fs_cpu_to_le32(inum);
 651         gen = inode->i_generation;
 652         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 653                                 sizeof(inum));
 654         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 655         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
 656
 657         inode->i_checksum_lo = old_lo;
 658         if (has_hi)
 659                 inode->i_checksum_hi = old_hi;
 660         return 0;
 661 }
 662
 663 int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 664                              struct ext2_inode_large *inode)
 665 {
 666         errcode_t retval;
 667         __u32 provided, calculated;
 668         unsigned int i, has_hi;
 669         char *cp;
 670
 671         if (!ext2fs_has_feature_metadata_csum(fs->super))
 672                 return 1;
 673
 674         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 675                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 676
 677         provided = ext2fs_le16_to_cpu(inode->i_checksum_lo);
 678         retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi);
 679         if (retval)
 680                 return 0;
 681         if (has_hi) {
 682                 __u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi);
 683                 provided |= hi << 16;
 684         } else
 685                 calculated &= 0xFFFF;
 686
 687         if (provided == calculated)
 688                 return 1;
 689
 690         /*
 691          * If the checksum didn't match, it's possible it was due to
 692          * the inode being all zero's.  It's unlikely this is the
 693          * case, but it can happen.  So check for it here.  (We only
 694          * check the base inode since that's good enough, and it's not
 695          * worth the bother to figure out how much of the extended
 696          * inode, if any, is present.)
 697          */
 698         for (cp = (char *) inode, i = 0;
 699              i < sizeof(struct ext2_inode);
 700              cp++, i++)
 701                 if (*cp)
 702                         return 0;
 703         return 1;               /* Inode must have been all zero's */
 704 }
 705
 706 errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
 707                            struct ext2_inode_large *inode)
 708 {
 709         errcode_t retval;
 710         __u32 crc;
 711         int has_hi;
 712
 713         if (!ext2fs_has_feature_metadata_csum(fs->super))
 714                 return 0;
 715
 716         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 717                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 718
 719         retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
 720         if (retval)
 721                 return retval;
 722         inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
 723         if (has_hi)
 724                 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
 725         return 0;
 726 }
 727
 728 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 729 {
 730         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 731                                                          group);
 732         size_t offset, size = EXT2_DESC_SIZE(fs->super);
 733         __u16 crc = 0;
 734 #ifdef WORDS_BIGENDIAN
 735         struct ext4_group_desc swabdesc;
 736         size_t save_size = size;
 737         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 738         struct ext2_group_desc *save_desc = desc;
 739
 740         /* Have to swab back to little-endian to do the checksum */
 741         if (size > ext4_bg_size)
 742                 size = ext4_bg_size;
 743         memcpy(&swabdesc, desc, size);
 744         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 745         desc = (struct ext2_group_desc *) &swabdesc;
 746         group = ext2fs_swab32(group);
 747 #endif
 748
 749         if (ext2fs_has_feature_metadata_csum(fs->super)) {
 750                 /* new metadata csum code */
 751                 __u16 old_crc;
 752                 __u32 crc32;
 753
 754                 old_crc = desc->bg_checksum;
 755                 desc->bg_checksum = 0;
 756                 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
 757                                          sizeof(group));
 758                 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
 759                                          size);
 760                 desc->bg_checksum = old_crc;
 761 #ifdef WORDS_BIGENDIAN
 762                 if (save_size > ext4_bg_size)
 763                         crc32 = ext2fs_crc32c_le(crc32,
 764                                      (unsigned char *)save_desc + ext4_bg_size,
 765                                      save_size - ext4_bg_size);
 766 #endif
 767                 crc = crc32 & 0xFFFF;
 768                 goto out;
 769         }
 770
 771         /* old crc16 code */
 772         offset = offsetof(struct ext2_group_desc, bg_checksum);
 773         crc = ext2fs_crc16(~0, fs->super->s_uuid,
 774                            sizeof(fs->super->s_uuid));
 775         crc = ext2fs_crc16(crc, &group, sizeof(group));
 776         crc = ext2fs_crc16(crc, desc, offset);
 777         offset += sizeof(desc->bg_checksum); /* skip checksum */
 778         /* for checksum of struct ext4_group_desc do the rest...*/
 779         if (offset < size) {
 780                 crc = ext2fs_crc16(crc, (char *)desc + offset,
 781                                    size - offset);
 782         }
 783 #ifdef WORDS_BIGENDIAN
 784         /*
 785          * If the size of the bg descriptor is greater than 64
 786          * bytes, which is the size of the traditional ext4 bg
 787          * descriptor, checksum the rest of the descriptor here
 788          */
 789         if (save_size > ext4_bg_size)
 790                 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
 791                                    save_size - ext4_bg_size);
 792 #endif
 793
 794 out:
 795         return crc;
 796 }
 797
 798 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
 799 {
 800         if (ext2fs_has_group_desc_csum(fs) &&
 801             (ext2fs_bg_checksum(fs, group) !=
 802              ext2fs_group_desc_csum(fs, group)))
 803                 return 0;
 804
 805         return 1;
 806 }
 807
 808 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
 809 {
 810         if (!ext2fs_has_group_desc_csum(fs))
 811                 return;
 812
 813         /* ext2fs_bg_checksum_set() sets the actual checksum field but
 814          * does not calculate the checksum itself. */
 815         ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
 816 }
 817
 818 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
 819                                    __u32 inodes_per_grp, dgrp_t grp_no)
 820 {
 821         ext2_ino_t i, start_ino, end_ino;
 822
 823         start_ino = grp_no * inodes_per_grp + 1;
 824         end_ino = start_ino + inodes_per_grp - 1;
 825
 826         for (i = end_ino; i >= start_ino; i--) {
 827                 if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
 828                         return i - start_ino + 1;
 829         }
 830         return inodes_per_grp;
 831 }
 832
 833 /* update the bitmap flags, set the itable high watermark, and calculate
 834  * checksums for the group descriptors */
 835 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
 836 {
 837         struct ext2_super_block *sb = fs->super;
 838         int dirty = 0;
 839         dgrp_t i;
 840
 841         if (!fs->inode_map)
 842                 return EXT2_ET_NO_INODE_BITMAP;
 843
 844         if (!ext2fs_has_group_desc_csum(fs))
 845                 return 0;
 846
 847         for (i = 0; i < fs->group_desc_count; i++) {
 848                 __u32 old_csum = ext2fs_bg_checksum(fs, i);
 849                 __u32 old_unused = ext2fs_bg_itable_unused(fs, i);
 850                 __u32 old_flags = ext2fs_bg_flags(fs, i);
 851                 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
 852                 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
 853
 854                 if (old_free_blocks_count == sb->s_blocks_per_group &&
 855                     i != fs->group_desc_count - 1)
 856                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 857
 858                 if (old_free_inodes_count == sb->s_inodes_per_group) {
 859                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 860                         ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
 861                 } else {
 862                         int unused =
 863                                 sb->s_inodes_per_group -
 864                                 find_last_inode_ingrp(fs->inode_map,
 865                                                       sb->s_inodes_per_group, i);
 866
 867                         ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
 868                         ext2fs_bg_itable_unused_set(fs, i, unused);
 869                 }
 870
 871                 ext2fs_group_desc_csum_set(fs, i);
 872                 if (old_flags != ext2fs_bg_flags(fs, i))
 873                         dirty = 1;
 874                 if (old_unused != ext2fs_bg_itable_unused(fs, i))
 875                         dirty = 1;
 876                 if (old_csum != ext2fs_bg_checksum(fs, i))
 877                         dirty = 1;
 878         }
 879         if (dirty)
 880                 ext2fs_mark_super_dirty(fs);
 881         return 0;
 882 }
 883
 884 #ifdef DEBUG
 885 #include "e2p/e2p.h"
 886
 887 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 888 {
 889         __u16 crc1, crc2, crc3;
 890         dgrp_t swabgroup;
 891         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 892                                                          group);
 893         size_t size = EXT2_DESC_SIZE(fs->super);
 894         struct ext2_super_block *sb = fs->super;
 895         int offset = offsetof(struct ext2_group_desc, bg_checksum);
 896 #ifdef WORDS_BIGENDIAN
 897         struct ext4_group_desc swabdesc;
 898         struct ext2_group_desc *save_desc = desc;
 899         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 900         size_t save_size = size;
 901 #endif
 902
 903 #ifdef WORDS_BIGENDIAN
 904         /* Have to swab back to little-endian to do the checksum */
 905         if (size > ext4_bg_size)
 906                 size = ext4_bg_size;
 907         memcpy(&swabdesc, desc, size);
 908         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 909         desc = (struct ext2_group_desc *) &swabdesc;
 910
 911         swabgroup = ext2fs_swab32(group);
 912 #else
 913         swabgroup = group;
 914 #endif
 915
 916         crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
 917         crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
 918         crc3 = ext2fs_crc16(crc2, desc, offset);
 919         offset += sizeof(desc->bg_checksum); /* skip checksum */
 920         /* for checksum of struct ext4_group_desc do the rest...*/
 921         if (offset < size)
 922                 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
 923 #ifdef WORDS_BIGENDIAN
 924         if (save_size > ext4_bg_size)
 925                 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
 926                                     save_size - ext4_bg_size);
 927 #endif
 928
 929         printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 930                msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 931                ext2fs_group_desc_csum(fs, group));
 932 }
 933
 934 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
 935                               0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
 936
 937 int main(int argc, char **argv)
 938 {
 939         struct ext2_super_block param;
 940         errcode_t               retval;
 941         ext2_filsys             fs;
 942         int                     i;
 943         __u16 csum1, csum2, csum_known = 0xd3a4;
 944
 945         memset(&param, 0, sizeof(param));
 946         ext2fs_blocks_count_set(&param, 32768);
 947 #if 0
 948         param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 949         param.s_desc_size = 128;
 950         csum_known = 0x5b6e;
 951 #endif
 952
 953         retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 954                                    test_io_manager, &fs);
 955         if (retval) {
 956                 com_err("setup", retval,
 957                         "While initializing filesystem");
 958                 exit(1);
 959         }
 960         memcpy(fs->super->s_uuid, sb_uuid, 16);
 961         fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 962
 963         for (i=0; i < fs->group_desc_count; i++) {
 964                 ext2fs_block_bitmap_loc_set(fs, i, 124);
 965                 ext2fs_inode_bitmap_loc_set(fs, i, 125);
 966                 ext2fs_inode_table_loc_set(fs, i, 126);
 967                 ext2fs_bg_free_blocks_count_set(fs, i, 31119);
 968                 ext2fs_bg_free_inodes_count_set(fs, i, 15701);
 969                 ext2fs_bg_used_dirs_count_set(fs, i, 2);
 970                 ext2fs_bg_flags_zap(fs, i);
 971         };
 972
 973         csum1 = ext2fs_group_desc_csum(fs, 0);
 974         print_csum("csum0000", fs, 0);
 975
 976         if (csum1 != csum_known) {
 977                 printf("checksum for group 0 should be %04x\n", csum_known);
 978                 exit(1);
 979         }
 980         csum2 = ext2fs_group_desc_csum(fs, 1);
 981         print_csum("csum0001", fs, 1);
 982         if (csum1 == csum2) {
 983                 printf("checksums for different groups shouldn't match\n");
 984                 exit(1);
 985         }
 986         csum2 = ext2fs_group_desc_csum(fs, 2);
 987         print_csum("csumffff", fs, 2);
 988         if (csum1 == csum2) {
 989                 printf("checksums for different groups shouldn't match\n");
 990                 exit(1);
 991         }
 992         ext2fs_bg_checksum_set(fs, 0, csum1);
 993         csum2 = ext2fs_group_desc_csum(fs, 0);
 994         print_csum("csum_set", fs, 0);
 995         if (csum1 != csum2) {
 996                 printf("checksums should not depend on checksum field\n");
 997                 exit(1);
 998         }
 999         if (!ext2fs_group_desc_csum_verify(fs, 0)) {
1000                 printf("checksums should verify against gd_checksum\n");
1001                 exit(1);
1002         }
1003         memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
1004         print_csum("new_uuid", fs, 0);
1005         if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
1006                 printf("checksums for different filesystems shouldn't match\n");
1007                 exit(1);
1008         }
1009         csum1 = ext2fs_group_desc_csum(fs, 0);
1010         ext2fs_bg_checksum_set(fs, 0, csum1);
1011         print_csum("csum_new", fs, 0);
1012         ext2fs_bg_free_blocks_count_set(fs, 0, 1);
1013         csum2 = ext2fs_group_desc_csum(fs, 0);
1014         print_csum("csum_blk", fs, 0);
1015         if (csum1 == csum2) {
1016                 printf("checksums for different data shouldn't match\n");
1017                 exit(1);
1018         }
1019         ext2fs_free(fs);
1020
1021         return 0;
1022 }
1023 #endif