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         if (fs->blocksize < 1024)
 267                 return EXT2_FILSYS_CORRUPTED; /* Should never happen */
 268
 269         d = dirent;
 270         top = EXT2_DIRENT_TAIL(dirent, fs->blocksize);
 271
 272         while ((void *) d < top) {
 273                 rec_len = translate(d->rec_len);
 274                 if ((rec_len < 8) || (rec_len & 0x03))
 275                         return EXT2_ET_DIR_CORRUPTED;
 276                 d = (struct ext2_dir_entry *)(((char *)d) + rec_len);
 277         }
 278
 279         if ((char *)d > ((char *)dirent + fs->blocksize))
 280                         return EXT2_ET_DIR_CORRUPTED;
 281         if (d != top)
 282                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 283
 284         t = (struct ext2_dir_entry_tail *)d;
 285         if (t->det_reserved_zero1 ||
 286             translate(t->det_rec_len) != sizeof(struct ext2_dir_entry_tail) ||
 287             translate(t->det_reserved_name_len) != EXT2_DIR_NAME_LEN_CSUM)
 288                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 289
 290         if (tt)
 291                 *tt = t;
 292         return retval;
 293 }
 294
 295 int ext2fs_dirent_has_tail(ext2_filsys fs, struct ext2_dir_entry *dirent)
 296 {
 297         return __get_dirent_tail(fs, dirent, NULL, 0) !=
 298                 EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 299 }
 300
 301 static errcode_t ext2fs_dirent_csum(ext2_filsys fs, ext2_ino_t inum,
 302                                     struct ext2_dir_entry *dirent, __u32 *crc,
 303                                     int size)
 304 {
 305         errcode_t retval;
 306         char *buf = (char *)dirent;
 307         __u32 gen;
 308         struct ext2_inode inode;
 309
 310         retval = ext2fs_read_inode(fs, inum, &inode);
 311         if (retval)
 312                 return retval;
 313
 314         inum = ext2fs_cpu_to_le32(inum);
 315         gen = ext2fs_cpu_to_le32(inode.i_generation);
 316         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 317                                 sizeof(inum));
 318         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 319         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 320
 321         return 0;
 322 }
 323
 324 int ext2fs_dirent_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 325                               struct ext2_dir_entry *dirent)
 326 {
 327         errcode_t retval;
 328         __u32 calculated;
 329         struct ext2_dir_entry_tail *t;
 330
 331         retval = __get_dirent_tail(fs, dirent, &t, 1);
 332         if (retval)
 333                 return 1;
 334
 335         /*
 336          * The checksum field is overlaid with the dirent->name field
 337          * so the swapfs.c functions won't change the endianness.
 338          */
 339         retval = ext2fs_dirent_csum(fs, inum, dirent, &calculated,
 340                                     (char *)t - (char *)dirent);
 341         if (retval)
 342                 return 0;
 343         return ext2fs_le32_to_cpu(t->det_checksum) == calculated;
 344 }
 345
 346 static errcode_t ext2fs_dirent_csum_set(ext2_filsys fs, ext2_ino_t inum,
 347                                         struct ext2_dir_entry *dirent)
 348 {
 349         errcode_t retval;
 350         __u32 crc;
 351         struct ext2_dir_entry_tail *t;
 352
 353         retval = __get_dirent_tail(fs, dirent, &t, 1);
 354         if (retval)
 355                 return retval;
 356
 357         /* swapfs.c functions don't change the checksum endianness */
 358         retval = ext2fs_dirent_csum(fs, inum, dirent, &crc,
 359                                     (char *)t - (char *)dirent);
 360         if (retval)
 361                 return retval;
 362         t->det_checksum = ext2fs_cpu_to_le32(crc);
 363         return 0;
 364 }
 365
 366 errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
 367                          struct ext2_dir_entry *dirent,
 368                          __u32 *crc, struct ext2_dx_tail **ret_t)
 369 {
 370         errcode_t retval;
 371         char *buf = (char *)dirent;
 372         int size;
 373         __u32 gen, dummy_csum = 0;
 374         struct ext2_inode inode;
 375         struct ext2_dx_tail *t;
 376         struct ext2_dx_countlimit *c;
 377         int count_offset, limit, count;
 378
 379         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 380         if (retval)
 381                 return retval;
 382         limit = ext2fs_le16_to_cpu(c->limit);
 383         count = ext2fs_le16_to_cpu(c->count);
 384         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 385             fs->blocksize - sizeof(struct ext2_dx_tail))
 386                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 387         /* htree structs are accessed in LE order */
 388         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 389
 390         size = count_offset + (count * sizeof(struct ext2_dx_entry));
 391
 392         retval = ext2fs_read_inode(fs, inum, &inode);
 393         if (retval)
 394                 return retval;
 395
 396         inum = ext2fs_cpu_to_le32(inum);
 397         gen = ext2fs_cpu_to_le32(inode.i_generation);
 398         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 399                                 sizeof(inum));
 400         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 401         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 402         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)t, 4);
 403         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&dummy_csum, 4);
 404
 405         if (ret_t)
 406                 *ret_t = t;
 407         return 0;
 408 }
 409
 410 static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 411                                  struct ext2_dir_entry *dirent)
 412 {
 413         __u32 calculated;
 414         errcode_t retval;
 415         struct ext2_dx_tail *t;
 416
 417         retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, &t);
 418         if (retval)
 419                 return 0;
 420
 421         return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
 422 }
 423
 424 static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
 425                                     struct ext2_dir_entry *dirent)
 426 {
 427         __u32 crc;
 428         errcode_t retval = 0;
 429         struct ext2_dx_tail *t;
 430
 431         retval = ext2fs_dx_csum(fs, inum, dirent, &crc, &t);
 432         if (retval)
 433                 return retval;
 434         t->dt_checksum = ext2fs_cpu_to_le32(crc);
 435         return retval;
 436 }
 437
 438 int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 439                                  struct ext2_dir_entry *dirent)
 440 {
 441         if (!ext2fs_has_feature_metadata_csum(fs->super))
 442                 return 1;
 443
 444         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 445                 return ext2fs_dirent_csum_verify(fs, inum, dirent);
 446         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 447                 return ext2fs_dx_csum_verify(fs, inum, dirent);
 448
 449         return 0;
 450 }
 451
 452 errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 453                                     struct ext2_dir_entry *dirent)
 454 {
 455         if (!ext2fs_has_feature_metadata_csum(fs->super))
 456                 return 0;
 457
 458         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 459                 return ext2fs_dirent_csum_set(fs, inum, dirent);
 460         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 461                 return ext2fs_dx_csum_set(fs, inum, dirent);
 462
 463         if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
 464                 return 0;
 465         return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 466 }
 467
 468 #define EXT3_EXTENT_TAIL_OFFSET(hdr)    (sizeof(struct ext3_extent_header) + \
 469         (sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
 470
 471 static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
 472 {
 473         return (struct ext3_extent_tail *)(((char *)h) +
 474                                            EXT3_EXTENT_TAIL_OFFSET(h));
 475 }
 476
 477 static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
 478                                           struct ext3_extent_header *eh,
 479                                           __u32 *crc)
 480 {
 481         int size;
 482         __u32 gen;
 483         errcode_t retval;
 484         struct ext2_inode inode;
 485
 486         size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
 487                                                       et_checksum);
 488
 489         retval = ext2fs_read_inode(fs, inum, &inode);
 490         if (retval)
 491                 return retval;
 492         inum = ext2fs_cpu_to_le32(inum);
 493         gen = ext2fs_cpu_to_le32(inode.i_generation);
 494         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 495                                 sizeof(inum));
 496         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 497         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
 498
 499         return 0;
 500 }
 501
 502 int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 503                                     struct ext3_extent_header *eh)
 504 {
 505         errcode_t retval;
 506         __u32 provided, calculated;
 507         struct ext3_extent_tail *t = get_extent_tail(eh);
 508
 509         /*
 510          * The extent tree structures are accessed in LE order, so we must
 511          * swap the checksum bytes here.
 512          */
 513         if (!ext2fs_has_feature_metadata_csum(fs->super))
 514                 return 1;
 515
 516         provided = ext2fs_le32_to_cpu(t->et_checksum);
 517         retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
 518         if (retval)
 519                 return 0;
 520
 521         return provided == calculated;
 522 }
 523
 524 errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 525                                        struct ext3_extent_header *eh)
 526 {
 527         errcode_t retval;
 528         __u32 crc;
 529         struct ext3_extent_tail *t = get_extent_tail(eh);
 530
 531         if (!ext2fs_has_feature_metadata_csum(fs->super))
 532                 return 0;
 533
 534         /*
 535          * The extent tree structures are accessed in LE order, so we must
 536          * swap the checksum bytes here.
 537          */
 538         retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
 539         if (retval)
 540                 return retval;
 541         t->et_checksum = ext2fs_cpu_to_le32(crc);
 542         return retval;
 543 }
 544
 545 int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 546                                     char *bitmap, int size)
 547 {
 548         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 549                         ext2fs_group_desc(fs, fs->group_desc, group);
 550         __u32 provided, calculated;
 551
 552         if (!ext2fs_has_feature_metadata_csum(fs->super))
 553                 return 1;
 554         provided = gdp->bg_inode_bitmap_csum_lo;
 555         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 556                                       size);
 557         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 558                 provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
 559         else
 560                 calculated &= 0xFFFF;
 561
 562         return provided == calculated;
 563 }
 564
 565 errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 566                                        char *bitmap, int size)
 567 {
 568         __u32 crc;
 569         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 570                         ext2fs_group_desc(fs, fs->group_desc, group);
 571
 572         if (!ext2fs_has_feature_metadata_csum(fs->super))
 573                 return 0;
 574
 575         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 576         gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
 577         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 578                 gdp->bg_inode_bitmap_csum_hi = crc >> 16;
 579
 580         return 0;
 581 }
 582
 583 int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 584                                     char *bitmap, int size)
 585 {
 586         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 587                         ext2fs_group_desc(fs, fs->group_desc, group);
 588         __u32 provided, calculated;
 589
 590         if (!ext2fs_has_feature_metadata_csum(fs->super))
 591                 return 1;
 592         provided = gdp->bg_block_bitmap_csum_lo;
 593         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 594                                       size);
 595         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 596                 provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
 597         else
 598                 calculated &= 0xFFFF;
 599
 600         return provided == calculated;
 601 }
 602
 603 errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 604                                        char *bitmap, int size)
 605 {
 606         __u32 crc;
 607         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 608                         ext2fs_group_desc(fs, fs->group_desc, group);
 609
 610         if (!ext2fs_has_feature_metadata_csum(fs->super))
 611                 return 0;
 612
 613         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 614         gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
 615         if (EXT2_DESC_SIZE(fs->super) >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 616                 gdp->bg_block_bitmap_csum_hi = crc >> 16;
 617
 618         return 0;
 619 }
 620
 621 static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
 622                                struct ext2_inode_large *inode,
 623                                __u32 *crc, int has_hi)
 624 {
 625         __u32 gen;
 626         struct ext2_inode_large *desc = inode;
 627         size_t size = EXT2_INODE_SIZE(fs->super);
 628         __u16 old_lo;
 629         __u16 old_hi = 0;
 630
 631         old_lo = inode->i_checksum_lo;
 632         inode->i_checksum_lo = 0;
 633         if (has_hi) {
 634                 old_hi = inode->i_checksum_hi;
 635                 inode->i_checksum_hi = 0;
 636         }
 637
 638         inum = ext2fs_cpu_to_le32(inum);
 639         gen = inode->i_generation;
 640         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 641                                 sizeof(inum));
 642         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 643         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
 644
 645         inode->i_checksum_lo = old_lo;
 646         if (has_hi)
 647                 inode->i_checksum_hi = old_hi;
 648         return 0;
 649 }
 650
 651 int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 652                              struct ext2_inode_large *inode)
 653 {
 654         errcode_t retval;
 655         __u32 provided, calculated;
 656         unsigned int i, has_hi;
 657         char *cp;
 658
 659         if (!ext2fs_has_feature_metadata_csum(fs->super))
 660                 return 1;
 661
 662         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 663                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 664
 665         provided = ext2fs_le16_to_cpu(inode->i_checksum_lo);
 666         retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi);
 667         if (retval)
 668                 return 0;
 669         if (has_hi) {
 670                 __u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi);
 671                 provided |= hi << 16;
 672         } else
 673                 calculated &= 0xFFFF;
 674
 675         if (provided == calculated)
 676                 return 1;
 677
 678         /*
 679          * If the checksum didn't match, it's possible it was due to
 680          * the inode being all zero's.  It's unlikely this is the
 681          * case, but it can happen.  So check for it here.  (We only
 682          * check the base inode since that's good enough, and it's not
 683          * worth the bother to figure out how much of the extended
 684          * inode, if any, is present.)
 685          */
 686         for (cp = (char *) inode, i = 0;
 687              i < sizeof(struct ext2_inode);
 688              cp++, i++)
 689                 if (*cp)
 690                         return 0;
 691         return 1;               /* Inode must have been all zero's */
 692 }
 693
 694 errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum,
 695                            struct ext2_inode_large *inode)
 696 {
 697         errcode_t retval;
 698         __u32 crc;
 699         int has_hi;
 700
 701         if (!ext2fs_has_feature_metadata_csum(fs->super))
 702                 return 0;
 703
 704         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 705                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 706
 707         retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
 708         if (retval)
 709                 return retval;
 710         inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
 711         if (has_hi)
 712                 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
 713         return 0;
 714 }
 715
 716 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 717 {
 718         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 719                                                          group);
 720         size_t offset, size = EXT2_DESC_SIZE(fs->super);
 721         __u16 crc = 0;
 722 #ifdef WORDS_BIGENDIAN
 723         struct ext4_group_desc swabdesc;
 724         size_t save_size = size;
 725         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 726         struct ext2_group_desc *save_desc = desc;
 727
 728         /* Have to swab back to little-endian to do the checksum */
 729         if (size > ext4_bg_size)
 730                 size = ext4_bg_size;
 731         memcpy(&swabdesc, desc, size);
 732         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 733         desc = (struct ext2_group_desc *) &swabdesc;
 734         group = ext2fs_swab32(group);
 735 #endif
 736
 737         if (ext2fs_has_feature_metadata_csum(fs->super)) {
 738                 /* new metadata csum code */
 739                 __u16 old_crc;
 740                 __u32 crc32;
 741
 742                 old_crc = desc->bg_checksum;
 743                 desc->bg_checksum = 0;
 744                 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
 745                                          sizeof(group));
 746                 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
 747                                          size);
 748                 desc->bg_checksum = old_crc;
 749 #ifdef WORDS_BIGENDIAN
 750                 if (save_size > ext4_bg_size)
 751                         crc32 = ext2fs_crc32c_le(crc32,
 752                                      (unsigned char *)save_desc + ext4_bg_size,
 753                                      save_size - ext4_bg_size);
 754 #endif
 755                 crc = crc32 & 0xFFFF;
 756                 goto out;
 757         }
 758
 759         /* old crc16 code */
 760         offset = offsetof(struct ext2_group_desc, bg_checksum);
 761         crc = ext2fs_crc16(~0, fs->super->s_uuid,
 762                            sizeof(fs->super->s_uuid));
 763         crc = ext2fs_crc16(crc, &group, sizeof(group));
 764         crc = ext2fs_crc16(crc, desc, offset);
 765         offset += sizeof(desc->bg_checksum); /* skip checksum */
 766         /* for checksum of struct ext4_group_desc do the rest...*/
 767         if (offset < size) {
 768                 crc = ext2fs_crc16(crc, (char *)desc + offset,
 769                                    size - offset);
 770         }
 771 #ifdef WORDS_BIGENDIAN
 772         /*
 773          * If the size of the bg descriptor is greater than 64
 774          * bytes, which is the size of the traditional ext4 bg
 775          * descriptor, checksum the rest of the descriptor here
 776          */
 777         if (save_size > ext4_bg_size)
 778                 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
 779                                    save_size - ext4_bg_size);
 780 #endif
 781
 782 out:
 783         return crc;
 784 }
 785
 786 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
 787 {
 788         if (ext2fs_has_group_desc_csum(fs) &&
 789             (ext2fs_bg_checksum(fs, group) !=
 790              ext2fs_group_desc_csum(fs, group)))
 791                 return 0;
 792
 793         return 1;
 794 }
 795
 796 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
 797 {
 798         if (!ext2fs_has_group_desc_csum(fs))
 799                 return;
 800
 801         /* ext2fs_bg_checksum_set() sets the actual checksum field but
 802          * does not calculate the checksum itself. */
 803         ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
 804 }
 805
 806 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
 807                                    __u32 inodes_per_grp, dgrp_t grp_no)
 808 {
 809         ext2_ino_t i, start_ino, end_ino;
 810
 811         start_ino = grp_no * inodes_per_grp + 1;
 812         end_ino = start_ino + inodes_per_grp - 1;
 813
 814         for (i = end_ino; i >= start_ino; i--) {
 815                 if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
 816                         return i - start_ino + 1;
 817         }
 818         return inodes_per_grp;
 819 }
 820
 821 /* update the bitmap flags, set the itable high watermark, and calculate
 822  * checksums for the group descriptors */
 823 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
 824 {
 825         struct ext2_super_block *sb = fs->super;
 826         int dirty = 0;
 827         dgrp_t i;
 828
 829         if (!fs->inode_map)
 830                 return EXT2_ET_NO_INODE_BITMAP;
 831
 832         if (!ext2fs_has_group_desc_csum(fs))
 833                 return 0;
 834
 835         for (i = 0; i < fs->group_desc_count; i++) {
 836                 __u32 old_csum = ext2fs_bg_checksum(fs, i);
 837                 __u32 old_unused = ext2fs_bg_itable_unused(fs, i);
 838                 __u32 old_flags = ext2fs_bg_flags(fs, i);
 839                 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
 840                 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
 841
 842                 if (old_free_blocks_count == sb->s_blocks_per_group &&
 843                     i != fs->group_desc_count - 1)
 844                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 845
 846                 if (old_free_inodes_count == sb->s_inodes_per_group) {
 847                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 848                         ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
 849                 } else {
 850                         int unused =
 851                                 sb->s_inodes_per_group -
 852                                 find_last_inode_ingrp(fs->inode_map,
 853                                                       sb->s_inodes_per_group, i);
 854
 855                         ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
 856                         ext2fs_bg_itable_unused_set(fs, i, unused);
 857                 }
 858
 859                 ext2fs_group_desc_csum_set(fs, i);
 860                 if (old_flags != ext2fs_bg_flags(fs, i))
 861                         dirty = 1;
 862                 if (old_unused != ext2fs_bg_itable_unused(fs, i))
 863                         dirty = 1;
 864                 if (old_csum != ext2fs_bg_checksum(fs, i))
 865                         dirty = 1;
 866         }
 867         if (dirty)
 868                 ext2fs_mark_super_dirty(fs);
 869         return 0;
 870 }
 871
 872 #ifdef DEBUG
 873 #include "e2p/e2p.h"
 874
 875 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 876 {
 877         __u16 crc1, crc2, crc3;
 878         dgrp_t swabgroup;
 879         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 880                                                          group);
 881         size_t size = EXT2_DESC_SIZE(fs->super);
 882         struct ext2_super_block *sb = fs->super;
 883         int offset = offsetof(struct ext2_group_desc, bg_checksum);
 884 #ifdef WORDS_BIGENDIAN
 885         struct ext4_group_desc swabdesc;
 886         struct ext2_group_desc *save_desc = desc;
 887         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 888         size_t save_size = size;
 889 #endif
 890
 891 #ifdef WORDS_BIGENDIAN
 892         /* Have to swab back to little-endian to do the checksum */
 893         if (size > ext4_bg_size)
 894                 size = ext4_bg_size;
 895         memcpy(&swabdesc, desc, size);
 896         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 897         desc = (struct ext2_group_desc *) &swabdesc;
 898
 899         swabgroup = ext2fs_swab32(group);
 900 #else
 901         swabgroup = group;
 902 #endif
 903
 904         crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
 905         crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
 906         crc3 = ext2fs_crc16(crc2, desc, offset);
 907         offset += sizeof(desc->bg_checksum); /* skip checksum */
 908         /* for checksum of struct ext4_group_desc do the rest...*/
 909         if (offset < size)
 910                 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
 911 #ifdef WORDS_BIGENDIAN
 912         if (save_size > ext4_bg_size)
 913                 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
 914                                     save_size - ext4_bg_size);
 915 #endif
 916
 917         printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 918                msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 919                ext2fs_group_desc_csum(fs, group));
 920 }
 921
 922 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
 923                               0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
 924
 925 int main(int argc, char **argv)
 926 {
 927         struct ext2_super_block param;
 928         errcode_t               retval;
 929         ext2_filsys             fs;
 930         int                     i;
 931         __u16 csum1, csum2, csum_known = 0xd3a4;
 932
 933         memset(&param, 0, sizeof(param));
 934         ext2fs_blocks_count_set(&param, 32768);
 935 #if 0
 936         param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 937         param.s_desc_size = 128;
 938         csum_known = 0x5b6e;
 939 #endif
 940
 941         retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 942                                    test_io_manager, &fs);
 943         if (retval) {
 944                 com_err("setup", retval,
 945                         "While initializing filesystem");
 946                 exit(1);
 947         }
 948         memcpy(fs->super->s_uuid, sb_uuid, 16);
 949         fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 950
 951         for (i=0; i < fs->group_desc_count; i++) {
 952                 ext2fs_block_bitmap_loc_set(fs, i, 124);
 953                 ext2fs_inode_bitmap_loc_set(fs, i, 125);
 954                 ext2fs_inode_table_loc_set(fs, i, 126);
 955                 ext2fs_bg_free_blocks_count_set(fs, i, 31119);
 956                 ext2fs_bg_free_inodes_count_set(fs, i, 15701);
 957                 ext2fs_bg_used_dirs_count_set(fs, i, 2);
 958                 ext2fs_bg_flags_zap(fs, i);
 959         };
 960
 961         csum1 = ext2fs_group_desc_csum(fs, 0);
 962         print_csum("csum0000", fs, 0);
 963
 964         if (csum1 != csum_known) {
 965                 printf("checksum for group 0 should be %04x\n", csum_known);
 966                 exit(1);
 967         }
 968         csum2 = ext2fs_group_desc_csum(fs, 1);
 969         print_csum("csum0001", fs, 1);
 970         if (csum1 == csum2) {
 971                 printf("checksums for different groups shouldn't match\n");
 972                 exit(1);
 973         }
 974         csum2 = ext2fs_group_desc_csum(fs, 2);
 975         print_csum("csumffff", fs, 2);
 976         if (csum1 == csum2) {
 977                 printf("checksums for different groups shouldn't match\n");
 978                 exit(1);
 979         }
 980         ext2fs_bg_checksum_set(fs, 0, csum1);
 981         csum2 = ext2fs_group_desc_csum(fs, 0);
 982         print_csum("csum_set", fs, 0);
 983         if (csum1 != csum2) {
 984                 printf("checksums should not depend on checksum field\n");
 985                 exit(1);
 986         }
 987         if (!ext2fs_group_desc_csum_verify(fs, 0)) {
 988                 printf("checksums should verify against gd_checksum\n");
 989                 exit(1);
 990         }
 991         memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
 992         print_csum("new_uuid", fs, 0);
 993         if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
 994                 printf("checksums for different filesystems shouldn't match\n");
 995                 exit(1);
 996         }
 997         csum1 = ext2fs_group_desc_csum(fs, 0);
 998         ext2fs_bg_checksum_set(fs, 0, csum1);
 999         print_csum("csum_new", fs, 0);
1000         ext2fs_bg_free_blocks_count_set(fs, 0, 1);
1001         csum2 = ext2fs_group_desc_csum(fs, 0);
1002         print_csum("csum_blk", fs, 0);
1003         if (csum1 == csum2) {
1004                 printf("checksums for different data shouldn't match\n");
1005                 exit(1);
1006         }
1007         ext2fs_free(fs);
1008
1009         return 0;
1010 }
1011 #endif