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                 fs->csum_seed = ext2fs_crc32c_le(~0, fs->super->s_uuid,
  39                                                  sizeof(fs->super->s_uuid));
  40 }
  41
  42 static __u32 ext2fs_mmp_csum(ext2_filsys fs, struct mmp_struct *mmp)
  43 {
  44         int offset = offsetof(struct mmp_struct, mmp_checksum);
  45
  46         return ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)mmp, offset);
  47 }
  48
  49 int ext2fs_mmp_csum_verify(ext2_filsys fs, struct mmp_struct *mmp)
  50 {
  51         __u32 calculated;
  52
  53         if (!ext2fs_has_feature_metadata_csum(fs->super))
  54                 return 1;
  55
  56         calculated = ext2fs_mmp_csum(fs, mmp);
  57
  58         return ext2fs_le32_to_cpu(mmp->mmp_checksum) == calculated;
  59 }
  60
  61 errcode_t ext2fs_mmp_csum_set(ext2_filsys fs, struct mmp_struct *mmp)
  62 {
  63         __u32 crc;
  64
  65         if (!ext2fs_has_feature_metadata_csum(fs->super))
  66                 return 0;
  67
  68         crc = ext2fs_mmp_csum(fs, mmp);
  69         mmp->mmp_checksum = ext2fs_cpu_to_le32(crc);
  70
  71         return 0;
  72 }
  73
  74 int ext2fs_verify_csum_type(ext2_filsys fs, struct ext2_super_block *sb)
  75 {
  76         if (!ext2fs_has_feature_metadata_csum(fs->super))
  77                 return 1;
  78
  79         return sb->s_checksum_type == EXT2_CRC32C_CHKSUM;
  80 }
  81
  82 static __u32 ext2fs_superblock_csum(ext2_filsys fs EXT2FS_ATTR((unused)),
  83                                     struct ext2_super_block *sb)
  84 {
  85         int offset = offsetof(struct ext2_super_block, s_checksum);
  86
  87         return ext2fs_crc32c_le(~0, (unsigned char *)sb, offset);
  88 }
  89
  90 /* NOTE: The input to this function MUST be in LE order */
  91 int ext2fs_superblock_csum_verify(ext2_filsys fs, struct ext2_super_block *sb)
  92 {
  93         __u32 flag, calculated;
  94
  95         if (fs->flags & EXT2_FLAG_SWAP_BYTES)
  96                 flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
  97         else
  98                 flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
  99
 100         if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
 101                 return 1;
 102
 103         calculated = ext2fs_superblock_csum(fs, sb);
 104
 105         return ext2fs_le32_to_cpu(sb->s_checksum) == calculated;
 106 }
 107
 108 /* NOTE: The input to this function MUST be in LE order */
 109 errcode_t ext2fs_superblock_csum_set(ext2_filsys fs,
 110                                      struct ext2_super_block *sb)
 111 {
 112         __u32 flag, crc;
 113
 114         if (fs->flags & EXT2_FLAG_SWAP_BYTES)
 115                 flag = EXT4_FEATURE_RO_COMPAT_METADATA_CSUM;
 116         else
 117                 flag = ext2fs_cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
 118
 119         if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, flag))
 120                 return 0;
 121
 122         crc = ext2fs_superblock_csum(fs, sb);
 123         sb->s_checksum = ext2fs_cpu_to_le32(crc);
 124
 125         return 0;
 126 }
 127
 128 static errcode_t ext2fs_ext_attr_block_csum(ext2_filsys fs,
 129                                             ext2_ino_t inum EXT2FS_ATTR((unused)),
 130                                             blk64_t block,
 131                                             struct ext2_ext_attr_header *hdr,
 132                                             __u32 *crc)
 133 {
 134         char *buf = (char *)hdr;
 135         __u32 old_crc = hdr->h_checksum;
 136
 137         hdr->h_checksum = 0;
 138         block = ext2fs_cpu_to_le64(block);
 139         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&block,
 140                                 sizeof(block));
 141         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, fs->blocksize);
 142         hdr->h_checksum = old_crc;
 143
 144         return 0;
 145 }
 146
 147 int ext2fs_ext_attr_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 148                                       blk64_t block,
 149                                       struct ext2_ext_attr_header *hdr)
 150 {
 151         __u32 calculated;
 152         errcode_t retval;
 153
 154         if (!ext2fs_has_feature_metadata_csum(fs->super))
 155                 return 1;
 156
 157         retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &calculated);
 158         if (retval)
 159                 return 0;
 160
 161         return ext2fs_le32_to_cpu(hdr->h_checksum) == calculated;
 162 }
 163
 164 errcode_t ext2fs_ext_attr_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 165                                          blk64_t block,
 166                                          struct ext2_ext_attr_header *hdr)
 167 {
 168         errcode_t retval;
 169         __u32 crc;
 170
 171         if (!ext2fs_has_feature_metadata_csum(fs->super))
 172                 return 0;
 173
 174         retval = ext2fs_ext_attr_block_csum(fs, inum, block, hdr, &crc);
 175         if (retval)
 176                 return retval;
 177         hdr->h_checksum = ext2fs_cpu_to_le32(crc);
 178         return 0;
 179 }
 180
 181 static __u16 do_nothing16(__u16 x)
 182 {
 183         return x;
 184 }
 185
 186 static __u16 disk_to_host16(__u16 x)
 187 {
 188         return ext2fs_le16_to_cpu(x);
 189 }
 190
 191 static errcode_t __get_dx_countlimit(ext2_filsys fs,
 192                                      struct ext2_dir_entry *dirent,
 193                                      struct ext2_dx_countlimit **cc,
 194                                      int *offset,
 195                                      int need_swab)
 196 {
 197         struct ext2_dir_entry *dp;
 198         struct ext2_dx_root_info *root;
 199         struct ext2_dx_countlimit *c;
 200         int count_offset, max_sane_entries;
 201         unsigned int rec_len;
 202         __u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
 203
 204         rec_len = translate(dirent->rec_len);
 205
 206         if (rec_len == fs->blocksize && translate(dirent->name_len) == 0)
 207                 count_offset = 8;
 208         else if (rec_len == 12) {
 209                 dp = (struct ext2_dir_entry *)(((char *)dirent) + rec_len);
 210                 rec_len = translate(dp->rec_len);
 211                 if (rec_len != fs->blocksize - 12)
 212                         return EXT2_ET_DB_NOT_FOUND;
 213                 root = (struct ext2_dx_root_info *)(((char *)dp + 12));
 214                 if (root->reserved_zero ||
 215                     root->info_length != sizeof(struct ext2_dx_root_info))
 216                         return EXT2_ET_DB_NOT_FOUND;
 217                 count_offset = 32;
 218         } else
 219                 return EXT2_ET_DB_NOT_FOUND;
 220
 221         c = (struct ext2_dx_countlimit *)(((char *)dirent) + count_offset);
 222         max_sane_entries = (fs->blocksize - count_offset) /
 223                            sizeof(struct ext2_dx_entry);
 224         if (ext2fs_le16_to_cpu(c->limit) > max_sane_entries ||
 225             ext2fs_le16_to_cpu(c->count) > max_sane_entries)
 226                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 227
 228         if (offset)
 229                 *offset = count_offset;
 230         if (cc)
 231                 *cc = c;
 232
 233         return 0;
 234 }
 235
 236 errcode_t ext2fs_get_dx_countlimit(ext2_filsys fs,
 237                                    struct ext2_dir_entry *dirent,
 238                                    struct ext2_dx_countlimit **cc,
 239                                    int *offset)
 240 {
 241         return __get_dx_countlimit(fs, dirent, cc, offset, 0);
 242 }
 243
 244 void ext2fs_initialize_dirent_tail(ext2_filsys fs,
 245                                    struct ext2_dir_entry_tail *t)
 246 {
 247         memset(t, 0, sizeof(struct ext2_dir_entry_tail));
 248         ext2fs_set_rec_len(fs, sizeof(struct ext2_dir_entry_tail),
 249                            (struct ext2_dir_entry *)t);
 250         t->det_reserved_name_len = EXT2_DIR_NAME_LEN_CSUM;
 251 }
 252
 253 static errcode_t __get_dirent_tail(ext2_filsys fs,
 254                                    struct ext2_dir_entry *dirent,
 255                                    struct ext2_dir_entry_tail **tt,
 256                                    int need_swab)
 257 {
 258         struct ext2_dir_entry *d;
 259         void *top;
 260         struct ext2_dir_entry_tail *t;
 261         unsigned int rec_len;
 262         errcode_t retval = 0;
 263         __u16 (*translate)(__u16) = (need_swab ? disk_to_host16 : do_nothing16);
 264
 265         d = dirent;
 266         top = EXT2_DIRENT_TAIL(dirent, fs->blocksize);
 267
 268         rec_len = translate(d->rec_len);
 269         while (rec_len && !(rec_len & 0x3)) {
 270                 d = (struct ext2_dir_entry *)(((char *)d) + rec_len);
 271                 if ((void *)d >= top)
 272                         break;
 273                 rec_len = translate(d->rec_len);
 274         }
 275
 276         if (d != top)
 277                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 278
 279         t = (struct ext2_dir_entry_tail *)d;
 280         if (t->det_reserved_zero1 ||
 281             translate(t->det_rec_len) != sizeof(struct ext2_dir_entry_tail) ||
 282             translate(t->det_reserved_name_len) != EXT2_DIR_NAME_LEN_CSUM)
 283                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 284
 285         if (tt)
 286                 *tt = t;
 287         return retval;
 288 }
 289
 290 int ext2fs_dirent_has_tail(ext2_filsys fs, struct ext2_dir_entry *dirent)
 291 {
 292         return __get_dirent_tail(fs, dirent, NULL, 0) == 0;
 293 }
 294
 295 static errcode_t ext2fs_dirent_csum(ext2_filsys fs, ext2_ino_t inum,
 296                                     struct ext2_dir_entry *dirent, __u32 *crc,
 297                                     int size)
 298 {
 299         errcode_t retval;
 300         char *buf = (char *)dirent;
 301         __u32 gen;
 302         struct ext2_inode inode;
 303
 304         retval = ext2fs_read_inode(fs, inum, &inode);
 305         if (retval)
 306                 return retval;
 307
 308         inum = ext2fs_cpu_to_le32(inum);
 309         gen = ext2fs_cpu_to_le32(inode.i_generation);
 310         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 311                                 sizeof(inum));
 312         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 313         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 314
 315         return 0;
 316 }
 317
 318 int ext2fs_dirent_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 319                               struct ext2_dir_entry *dirent)
 320 {
 321         errcode_t retval;
 322         __u32 calculated;
 323         struct ext2_dir_entry_tail *t;
 324
 325         retval = __get_dirent_tail(fs, dirent, &t, 1);
 326         if (retval)
 327                 return 1;
 328
 329         /*
 330          * The checksum field is overlaid with the dirent->name field
 331          * so the swapfs.c functions won't change the endianness.
 332          */
 333         retval = ext2fs_dirent_csum(fs, inum, dirent, &calculated,
 334                                     (char *)t - (char *)dirent);
 335         if (retval)
 336                 return 0;
 337         return ext2fs_le32_to_cpu(t->det_checksum) == calculated;
 338 }
 339
 340 static errcode_t ext2fs_dirent_csum_set(ext2_filsys fs, ext2_ino_t inum,
 341                                         struct ext2_dir_entry *dirent)
 342 {
 343         errcode_t retval;
 344         __u32 crc;
 345         struct ext2_dir_entry_tail *t;
 346
 347         retval = __get_dirent_tail(fs, dirent, &t, 1);
 348         if (retval)
 349                 return retval;
 350
 351         /* swapfs.c functions don't change the checksum endianness */
 352         retval = ext2fs_dirent_csum(fs, inum, dirent, &crc,
 353                                     (char *)t - (char *)dirent);
 354         if (retval)
 355                 return retval;
 356         t->det_checksum = ext2fs_cpu_to_le32(crc);
 357         return 0;
 358 }
 359
 360 static errcode_t ext2fs_dx_csum(ext2_filsys fs, ext2_ino_t inum,
 361                                 struct ext2_dir_entry *dirent,
 362                                 __u32 *crc, int count_offset, int count,
 363                                 struct ext2_dx_tail *t)
 364 {
 365         errcode_t retval;
 366         char *buf = (char *)dirent;
 367         int size;
 368         __u32 old_csum, gen;
 369         struct ext2_inode inode;
 370
 371         size = count_offset + (count * sizeof(struct ext2_dx_entry));
 372         old_csum = t->dt_checksum;
 373         t->dt_checksum = 0;
 374
 375         retval = ext2fs_read_inode(fs, inum, &inode);
 376         if (retval)
 377                 return retval;
 378
 379         inum = ext2fs_cpu_to_le32(inum);
 380         gen = ext2fs_cpu_to_le32(inode.i_generation);
 381         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 382                                 sizeof(inum));
 383         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 384         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)buf, size);
 385         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)t,
 386                                 sizeof(struct ext2_dx_tail));
 387         t->dt_checksum = old_csum;
 388
 389         return 0;
 390 }
 391
 392 static int ext2fs_dx_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 393                                  struct ext2_dir_entry *dirent)
 394 {
 395         __u32 calculated;
 396         errcode_t retval;
 397         struct ext2_dx_countlimit *c;
 398         struct ext2_dx_tail *t;
 399         int count_offset, limit, count;
 400
 401         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 402         if (retval)
 403                 return 1;
 404         limit = ext2fs_le16_to_cpu(c->limit);
 405         count = ext2fs_le16_to_cpu(c->count);
 406         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 407             fs->blocksize - sizeof(struct ext2_dx_tail))
 408                 return 0;
 409         /* htree structs are accessed in LE order */
 410         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 411         retval = ext2fs_dx_csum(fs, inum, dirent, &calculated, count_offset,
 412                                 count, t);
 413         if (retval)
 414                 return 0;
 415
 416         return ext2fs_le32_to_cpu(t->dt_checksum) == calculated;
 417 }
 418
 419 static errcode_t ext2fs_dx_csum_set(ext2_filsys fs, ext2_ino_t inum,
 420                                     struct ext2_dir_entry *dirent)
 421 {
 422         __u32 crc;
 423         errcode_t retval = 0;
 424         struct ext2_dx_countlimit *c;
 425         struct ext2_dx_tail *t;
 426         int count_offset, limit, count;
 427
 428         retval = __get_dx_countlimit(fs, dirent, &c, &count_offset, 1);
 429         if (retval)
 430                 return retval;
 431         limit = ext2fs_le16_to_cpu(c->limit);
 432         count = ext2fs_le16_to_cpu(c->count);
 433         if (count_offset + (limit * sizeof(struct ext2_dx_entry)) >
 434             fs->blocksize - sizeof(struct ext2_dx_tail))
 435                 return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 436         t = (struct ext2_dx_tail *)(((struct ext2_dx_entry *)c) + limit);
 437
 438         /* htree structs are accessed in LE order */
 439         retval = ext2fs_dx_csum(fs, inum, dirent, &crc, count_offset, count, t);
 440         if (retval)
 441                 return retval;
 442         t->dt_checksum = ext2fs_cpu_to_le32(crc);
 443         return retval;
 444 }
 445
 446 int ext2fs_dir_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 447                                  struct ext2_dir_entry *dirent)
 448 {
 449         if (!ext2fs_has_feature_metadata_csum(fs->super))
 450                 return 1;
 451
 452         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 453                 return ext2fs_dirent_csum_verify(fs, inum, dirent);
 454         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 455                 return ext2fs_dx_csum_verify(fs, inum, dirent);
 456
 457         return 0;
 458 }
 459
 460 errcode_t ext2fs_dir_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 461                                     struct ext2_dir_entry *dirent)
 462 {
 463         if (!ext2fs_has_feature_metadata_csum(fs->super))
 464                 return 0;
 465
 466         if (__get_dirent_tail(fs, dirent, NULL, 1) == 0)
 467                 return ext2fs_dirent_csum_set(fs, inum, dirent);
 468         if (__get_dx_countlimit(fs, dirent, NULL, NULL, 1) == 0)
 469                 return ext2fs_dx_csum_set(fs, inum, dirent);
 470
 471         if (fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)
 472                 return 0;
 473         return EXT2_ET_DIR_NO_SPACE_FOR_CSUM;
 474 }
 475
 476 #define EXT3_EXTENT_TAIL_OFFSET(hdr)    (sizeof(struct ext3_extent_header) + \
 477         (sizeof(struct ext3_extent) * ext2fs_le16_to_cpu((hdr)->eh_max)))
 478
 479 static struct ext3_extent_tail *get_extent_tail(struct ext3_extent_header *h)
 480 {
 481         return (struct ext3_extent_tail *)(((char *)h) +
 482                                            EXT3_EXTENT_TAIL_OFFSET(h));
 483 }
 484
 485 static errcode_t ext2fs_extent_block_csum(ext2_filsys fs, ext2_ino_t inum,
 486                                           struct ext3_extent_header *eh,
 487                                           __u32 *crc)
 488 {
 489         int size;
 490         __u32 gen;
 491         errcode_t retval;
 492         struct ext2_inode inode;
 493
 494         size = EXT3_EXTENT_TAIL_OFFSET(eh) + offsetof(struct ext3_extent_tail,
 495                                                       et_checksum);
 496
 497         retval = ext2fs_read_inode(fs, inum, &inode);
 498         if (retval)
 499                 return retval;
 500         inum = ext2fs_cpu_to_le32(inum);
 501         gen = ext2fs_cpu_to_le32(inode.i_generation);
 502         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 503                                 sizeof(inum));
 504         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 505         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)eh, size);
 506
 507         return 0;
 508 }
 509
 510 int ext2fs_extent_block_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 511                                     struct ext3_extent_header *eh)
 512 {
 513         errcode_t retval;
 514         __u32 provided, calculated;
 515         struct ext3_extent_tail *t = get_extent_tail(eh);
 516
 517         /*
 518          * The extent tree structures are accessed in LE order, so we must
 519          * swap the checksum bytes here.
 520          */
 521         if (!ext2fs_has_feature_metadata_csum(fs->super))
 522                 return 1;
 523
 524         provided = ext2fs_le32_to_cpu(t->et_checksum);
 525         retval = ext2fs_extent_block_csum(fs, inum, eh, &calculated);
 526         if (retval)
 527                 return 0;
 528
 529         return provided == calculated;
 530 }
 531
 532 errcode_t ext2fs_extent_block_csum_set(ext2_filsys fs, ext2_ino_t inum,
 533                                        struct ext3_extent_header *eh)
 534 {
 535         errcode_t retval;
 536         __u32 crc;
 537         struct ext3_extent_tail *t = get_extent_tail(eh);
 538
 539         if (!ext2fs_has_feature_metadata_csum(fs->super))
 540                 return 0;
 541
 542         /*
 543          * The extent tree structures are accessed in LE order, so we must
 544          * swap the checksum bytes here.
 545          */
 546         retval = ext2fs_extent_block_csum(fs, inum, eh, &crc);
 547         if (retval)
 548                 return retval;
 549         t->et_checksum = ext2fs_cpu_to_le32(crc);
 550         return retval;
 551 }
 552
 553 int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 554                                     char *bitmap, int size)
 555 {
 556         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 557                         ext2fs_group_desc(fs, fs->group_desc, group);
 558         __u32 provided, calculated;
 559
 560         if (!ext2fs_has_feature_metadata_csum(fs->super))
 561                 return 1;
 562         provided = gdp->bg_inode_bitmap_csum_lo;
 563         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 564                                       size);
 565         if (fs->super->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 566                 provided |= (__u32)gdp->bg_inode_bitmap_csum_hi << 16;
 567         else
 568                 calculated &= 0xFFFF;
 569
 570         return provided == calculated;
 571 }
 572
 573 errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 574                                        char *bitmap, int size)
 575 {
 576         __u32 crc;
 577         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 578                         ext2fs_group_desc(fs, fs->group_desc, group);
 579
 580         if (!ext2fs_has_feature_metadata_csum(fs->super))
 581                 return 0;
 582
 583         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 584         gdp->bg_inode_bitmap_csum_lo = crc & 0xFFFF;
 585         if (fs->super->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 586                 gdp->bg_inode_bitmap_csum_hi = crc >> 16;
 587
 588         return 0;
 589 }
 590
 591 int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group,
 592                                     char *bitmap, int size)
 593 {
 594         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 595                         ext2fs_group_desc(fs, fs->group_desc, group);
 596         __u32 provided, calculated;
 597
 598         if (!ext2fs_has_feature_metadata_csum(fs->super))
 599                 return 1;
 600         provided = gdp->bg_block_bitmap_csum_lo;
 601         calculated = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap,
 602                                       size);
 603         if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 604                 provided |= (__u32)gdp->bg_block_bitmap_csum_hi << 16;
 605         else
 606                 calculated &= 0xFFFF;
 607
 608         return provided == calculated;
 609 }
 610
 611 errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group,
 612                                        char *bitmap, int size)
 613 {
 614         __u32 crc;
 615         struct ext4_group_desc *gdp = (struct ext4_group_desc *)
 616                         ext2fs_group_desc(fs, fs->group_desc, group);
 617
 618         if (!ext2fs_has_feature_metadata_csum(fs->super))
 619                 return 0;
 620
 621         crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)bitmap, size);
 622         gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF;
 623         if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION)
 624                 gdp->bg_block_bitmap_csum_hi = crc >> 16;
 625
 626         return 0;
 627 }
 628
 629 static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum,
 630                                struct ext2_inode_large *inode,
 631                                __u32 *crc, int has_hi)
 632 {
 633         __u32 gen;
 634         struct ext2_inode_large *desc = inode;
 635         size_t size = fs->super->s_inode_size;
 636         __u16 old_lo;
 637         __u16 old_hi = 0;
 638
 639         old_lo = inode->i_checksum_lo;
 640         inode->i_checksum_lo = 0;
 641         if (has_hi) {
 642                 old_hi = inode->i_checksum_hi;
 643                 inode->i_checksum_hi = 0;
 644         }
 645
 646         inum = ext2fs_cpu_to_le32(inum);
 647         gen = inode->i_generation;
 648         *crc = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&inum,
 649                                 sizeof(inum));
 650         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)&gen, sizeof(gen));
 651         *crc = ext2fs_crc32c_le(*crc, (unsigned char *)desc, size);
 652
 653         inode->i_checksum_lo = old_lo;
 654         if (has_hi)
 655                 inode->i_checksum_hi = old_hi;
 656         return 0;
 657 }
 658
 659 int ext2fs_inode_csum_verify(ext2_filsys fs, ext2_ino_t inum,
 660                              struct ext2_inode_large *inode)
 661 {
 662         errcode_t retval;
 663         __u32 provided, calculated;
 664         unsigned int i, has_hi;
 665         char *cp;
 666
 667         if (fs->super->s_creator_os != EXT2_OS_LINUX ||
 668             !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 (fs->super->s_creator_os != EXT2_OS_LINUX ||
 711             !ext2fs_has_feature_metadata_csum(fs->super))
 712                 return 0;
 713
 714         has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE &&
 715                   inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END);
 716
 717         retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi);
 718         if (retval)
 719                 return retval;
 720         inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF);
 721         if (has_hi)
 722                 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16);
 723         return 0;
 724 }
 725
 726 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 727 {
 728         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 729                                                          group);
 730         size_t offset, size = EXT2_DESC_SIZE(fs->super);
 731         __u16 crc = 0;
 732 #ifdef WORDS_BIGENDIAN
 733         struct ext4_group_desc swabdesc;
 734         size_t save_size = size;
 735         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 736         struct ext2_group_desc *save_desc = desc;
 737
 738         /* Have to swab back to little-endian to do the checksum */
 739         if (size > ext4_bg_size)
 740                 size = ext4_bg_size;
 741         memcpy(&swabdesc, desc, size);
 742         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 743         desc = (struct ext2_group_desc *) &swabdesc;
 744         group = ext2fs_swab32(group);
 745 #endif
 746
 747         if (ext2fs_has_feature_metadata_csum(fs->super)) {
 748                 /* new metadata csum code */
 749                 __u16 old_crc;
 750                 __u32 crc32;
 751
 752                 old_crc = desc->bg_checksum;
 753                 desc->bg_checksum = 0;
 754                 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group,
 755                                          sizeof(group));
 756                 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc,
 757                                          size);
 758                 desc->bg_checksum = old_crc;
 759 #ifdef WORDS_BIGENDIAN
 760                 if (save_size > ext4_bg_size)
 761                         crc32 = ext2fs_crc32c_le(crc32,
 762                                      (unsigned char *)save_desc + ext4_bg_size,
 763                                      save_size - ext4_bg_size);
 764 #endif
 765                 crc = crc32 & 0xFFFF;
 766                 goto out;
 767         }
 768
 769         /* old crc16 code */
 770         offset = offsetof(struct ext2_group_desc, bg_checksum);
 771         crc = ext2fs_crc16(~0, fs->super->s_uuid,
 772                            sizeof(fs->super->s_uuid));
 773         crc = ext2fs_crc16(crc, &group, sizeof(group));
 774         crc = ext2fs_crc16(crc, desc, offset);
 775         offset += sizeof(desc->bg_checksum); /* skip checksum */
 776         /* for checksum of struct ext4_group_desc do the rest...*/
 777         if (offset < size) {
 778                 crc = ext2fs_crc16(crc, (char *)desc + offset,
 779                                    size - offset);
 780         }
 781 #ifdef WORDS_BIGENDIAN
 782         /*
 783          * If the size of the bg descriptor is greater than 64
 784          * bytes, which is the size of the traditional ext4 bg
 785          * descriptor, checksum the rest of the descriptor here
 786          */
 787         if (save_size > ext4_bg_size)
 788                 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size,
 789                                    save_size - ext4_bg_size);
 790 #endif
 791
 792 out:
 793         return crc;
 794 }
 795
 796 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
 797 {
 798         if (ext2fs_has_group_desc_csum(fs) &&
 799             (ext2fs_bg_checksum(fs, group) !=
 800              ext2fs_group_desc_csum(fs, group)))
 801                 return 0;
 802
 803         return 1;
 804 }
 805
 806 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
 807 {
 808         if (!ext2fs_has_group_desc_csum(fs))
 809                 return;
 810
 811         /* ext2fs_bg_checksum_set() sets the actual checksum field but
 812          * does not calculate the checksum itself. */
 813         ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
 814 }
 815
 816 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
 817                                    __u32 inodes_per_grp, dgrp_t grp_no)
 818 {
 819         ext2_ino_t i, start_ino, end_ino;
 820
 821         start_ino = grp_no * inodes_per_grp + 1;
 822         end_ino = start_ino + inodes_per_grp - 1;
 823
 824         for (i = end_ino; i >= start_ino; i--) {
 825                 if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
 826                         return i - start_ino + 1;
 827         }
 828         return inodes_per_grp;
 829 }
 830
 831 /* update the bitmap flags, set the itable high watermark, and calculate
 832  * checksums for the group descriptors */
 833 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
 834 {
 835         struct ext2_super_block *sb = fs->super;
 836         int dirty = 0;
 837         dgrp_t i;
 838
 839         if (!fs->inode_map)
 840                 return EXT2_ET_NO_INODE_BITMAP;
 841
 842         if (!ext2fs_has_group_desc_csum(fs))
 843                 return 0;
 844
 845         for (i = 0; i < fs->group_desc_count; i++) {
 846                 __u32 old_csum = ext2fs_bg_checksum(fs, i);
 847                 __u32 old_unused = ext2fs_bg_itable_unused(fs, i);
 848                 __u32 old_flags = ext2fs_bg_flags(fs, i);
 849                 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
 850                 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i);
 851
 852                 if (old_free_blocks_count == sb->s_blocks_per_group &&
 853                     i != fs->group_desc_count - 1)
 854                         ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);
 855
 856                 if (old_free_inodes_count == sb->s_inodes_per_group) {
 857                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 858                         ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
 859                 } else {
 860                         int unused =
 861                                 sb->s_inodes_per_group -
 862                                 find_last_inode_ingrp(fs->inode_map,
 863                                                       sb->s_inodes_per_group, i);
 864
 865                         ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
 866                         ext2fs_bg_itable_unused_set(fs, i, unused);
 867                 }
 868
 869                 ext2fs_group_desc_csum_set(fs, i);
 870                 if (old_flags != ext2fs_bg_flags(fs, i))
 871                         dirty = 1;
 872                 if (old_unused != ext2fs_bg_itable_unused(fs, i))
 873                         dirty = 1;
 874                 if (old_csum != ext2fs_bg_checksum(fs, i))
 875                         dirty = 1;
 876         }
 877         if (dirty)
 878                 ext2fs_mark_super_dirty(fs);
 879         return 0;
 880 }
 881
 882 #ifdef DEBUG
 883 #include "e2p/e2p.h"
 884
 885 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 886 {
 887         __u16 crc1, crc2, crc3;
 888         dgrp_t swabgroup;
 889         struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
 890                                                          group);
 891         size_t size = EXT2_DESC_SIZE(fs->super);
 892         struct ext2_super_block *sb = fs->super;
 893         int offset = offsetof(struct ext2_group_desc, bg_checksum);
 894 #ifdef WORDS_BIGENDIAN
 895         struct ext4_group_desc swabdesc;
 896         struct ext2_group_desc *save_desc = desc;
 897         const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
 898         size_t save_size = size;
 899 #endif
 900
 901 #ifdef WORDS_BIGENDIAN
 902         /* Have to swab back to little-endian to do the checksum */
 903         if (size > ext4_bg_size)
 904                 size = ext4_bg_size;
 905         memcpy(&swabdesc, desc, size);
 906         ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 907         desc = (struct ext2_group_desc *) &swabdesc;
 908
 909         swabgroup = ext2fs_swab32(group);
 910 #else
 911         swabgroup = group;
 912 #endif
 913
 914         crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
 915         crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
 916         crc3 = ext2fs_crc16(crc2, desc, offset);
 917         offset += sizeof(desc->bg_checksum); /* skip checksum */
 918         /* for checksum of struct ext4_group_desc do the rest...*/
 919         if (offset < size)
 920                 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
 921 #ifdef WORDS_BIGENDIAN
 922         if (save_size > ext4_bg_size)
 923                 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
 924                                     save_size - ext4_bg_size);
 925 #endif
 926
 927         printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 928                msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 929                ext2fs_group_desc_csum(fs, group));
 930 }
 931
 932 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
 933                               0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
 934
 935 int main(int argc, char **argv)
 936 {
 937         struct ext2_super_block param;
 938         errcode_t               retval;
 939         ext2_filsys             fs;
 940         int                     i;
 941         __u16 csum1, csum2, csum_known = 0xd3a4;
 942
 943         memset(&param, 0, sizeof(param));
 944         ext2fs_blocks_count_set(&param, 32768);
 945 #if 0
 946         param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 947         param.s_desc_size = 128;
 948         csum_known = 0x5b6e;
 949 #endif
 950
 951         retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 952                                    test_io_manager, &fs);
 953         if (retval) {
 954                 com_err("setup", retval,
 955                         "While initializing filesystem");
 956                 exit(1);
 957         }
 958         memcpy(fs->super->s_uuid, sb_uuid, 16);
 959         fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
 960
 961         for (i=0; i < fs->group_desc_count; i++) {
 962                 ext2fs_block_bitmap_loc_set(fs, i, 124);
 963                 ext2fs_inode_bitmap_loc_set(fs, i, 125);
 964                 ext2fs_inode_table_loc_set(fs, i, 126);
 965                 ext2fs_bg_free_blocks_count_set(fs, i, 31119);
 966                 ext2fs_bg_free_inodes_count_set(fs, i, 15701);
 967                 ext2fs_bg_used_dirs_count_set(fs, i, 2);
 968                 ext2fs_bg_flags_zap(fs, i);
 969         };
 970
 971         csum1 = ext2fs_group_desc_csum(fs, 0);
 972         print_csum("csum0000", fs, 0);
 973
 974         if (csum1 != csum_known) {
 975                 printf("checksum for group 0 should be %04x\n", csum_known);
 976                 exit(1);
 977         }
 978         csum2 = ext2fs_group_desc_csum(fs, 1);
 979         print_csum("csum0001", fs, 1);
 980         if (csum1 == csum2) {
 981                 printf("checksums for different groups shouldn't match\n");
 982                 exit(1);
 983         }
 984         csum2 = ext2fs_group_desc_csum(fs, 2);
 985         print_csum("csumffff", fs, 2);
 986         if (csum1 == csum2) {
 987                 printf("checksums for different groups shouldn't match\n");
 988                 exit(1);
 989         }
 990         ext2fs_bg_checksum_set(fs, 0, csum1);
 991         csum2 = ext2fs_group_desc_csum(fs, 0);
 992         print_csum("csum_set", fs, 0);
 993         if (csum1 != csum2) {
 994                 printf("checksums should not depend on checksum field\n");
 995                 exit(1);
 996         }
 997         if (!ext2fs_group_desc_csum_verify(fs, 0)) {
 998                 printf("checksums should verify against gd_checksum\n");
 999                 exit(1);
1000         }
1001         memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
1002         print_csum("new_uuid", fs, 0);
1003         if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
1004                 printf("checksums for different filesystems shouldn't match\n");
1005                 exit(1);
1006         }
1007         csum1 = ext2fs_group_desc_csum(fs, 0);
1008         ext2fs_bg_checksum_set(fs, 0, csum1);
1009         print_csum("csum_new", fs, 0);
1010         ext2fs_bg_free_blocks_count_set(fs, 0, 1);
1011         csum2 = ext2fs_group_desc_csum(fs, 0);
1012         print_csum("csum_blk", fs, 0);
1013         if (csum1 == csum2) {
1014                 printf("checksums for different data shouldn't match\n");
1015                 exit(1);
1016         }
1017
1018         return 0;
1019 }
1020 #endif