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 (at) 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 (!ext2fs_has_feature_metadata_csum(fs->super)) 668 return 1; 669 670 has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE && 671 inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END); 672 673 provided = ext2fs_le16_to_cpu(inode->i_checksum_lo); 674 retval = ext2fs_inode_csum(fs, inum, inode, &calculated, has_hi); 675 if (retval) 676 return 0; 677 if (has_hi) { 678 __u32 hi = ext2fs_le16_to_cpu(inode->i_checksum_hi); 679 provided |= hi << 16; 680 } else 681 calculated &= 0xFFFF; 682 683 if (provided == calculated) 684 return 1; 685 686 /* 687 * If the checksum didn't match, it's possible it was due to 688 * the inode being all zero's. It's unlikely this is the 689 * case, but it can happen. So check for it here. (We only 690 * check the base inode since that's good enough, and it's not 691 * worth the bother to figure out how much of the extended 692 * inode, if any, is present.) 693 */ 694 for (cp = (char *) inode, i = 0; 695 i < sizeof(struct ext2_inode); 696 cp++, i++) 697 if (*cp) 698 return 0; 699 return 1; /* Inode must have been all zero's */ 700 } 701 702 errcode_t ext2fs_inode_csum_set(ext2_filsys fs, ext2_ino_t inum, 703 struct ext2_inode_large *inode) 704 { 705 errcode_t retval; 706 __u32 crc; 707 int has_hi; 708 709 if (!ext2fs_has_feature_metadata_csum(fs->super)) 710 return 0; 711 712 has_hi = (EXT2_INODE_SIZE(fs->super) > EXT2_GOOD_OLD_INODE_SIZE && 713 inode->i_extra_isize >= EXT4_INODE_CSUM_HI_EXTRA_END); 714 715 retval = ext2fs_inode_csum(fs, inum, inode, &crc, has_hi); 716 if (retval) 717 return retval; 718 inode->i_checksum_lo = ext2fs_cpu_to_le16(crc & 0xFFFF); 719 if (has_hi) 720 inode->i_checksum_hi = ext2fs_cpu_to_le16(crc >> 16); 721 return 0; 722 } 723 724 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group) 725 { 726 struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc, 727 group); 728 size_t offset, size = EXT2_DESC_SIZE(fs->super); 729 __u16 crc = 0; 730 #ifdef WORDS_BIGENDIAN 731 struct ext4_group_desc swabdesc; 732 size_t save_size = size; 733 const size_t ext4_bg_size = sizeof(struct ext4_group_desc); 734 struct ext2_group_desc *save_desc = desc; 735 736 /* Have to swab back to little-endian to do the checksum */ 737 if (size > ext4_bg_size) 738 size = ext4_bg_size; 739 memcpy(&swabdesc, desc, size); 740 ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc); 741 desc = (struct ext2_group_desc *) &swabdesc; 742 group = ext2fs_swab32(group); 743 #endif 744 745 if (ext2fs_has_feature_metadata_csum(fs->super)) { 746 /* new metadata csum code */ 747 __u16 old_crc; 748 __u32 crc32; 749 750 old_crc = desc->bg_checksum; 751 desc->bg_checksum = 0; 752 crc32 = ext2fs_crc32c_le(fs->csum_seed, (unsigned char *)&group, 753 sizeof(group)); 754 crc32 = ext2fs_crc32c_le(crc32, (unsigned char *)desc, 755 size); 756 desc->bg_checksum = old_crc; 757 #ifdef WORDS_BIGENDIAN 758 if (save_size > ext4_bg_size) 759 crc32 = ext2fs_crc32c_le(crc32, 760 (unsigned char *)save_desc + ext4_bg_size, 761 save_size - ext4_bg_size); 762 #endif 763 crc = crc32 & 0xFFFF; 764 goto out; 765 } 766 767 /* old crc16 code */ 768 offset = offsetof(struct ext2_group_desc, bg_checksum); 769 crc = ext2fs_crc16(~0, fs->super->s_uuid, 770 sizeof(fs->super->s_uuid)); 771 crc = ext2fs_crc16(crc, &group, sizeof(group)); 772 crc = ext2fs_crc16(crc, desc, offset); 773 offset += sizeof(desc->bg_checksum); /* skip checksum */ 774 /* for checksum of struct ext4_group_desc do the rest...*/ 775 if (offset < size) { 776 crc = ext2fs_crc16(crc, (char *)desc + offset, 777 size - offset); 778 } 779 #ifdef WORDS_BIGENDIAN 780 /* 781 * If the size of the bg descriptor is greater than 64 782 * bytes, which is the size of the traditional ext4 bg 783 * descriptor, checksum the rest of the descriptor here 784 */ 785 if (save_size > ext4_bg_size) 786 crc = ext2fs_crc16(crc, (char *)save_desc + ext4_bg_size, 787 save_size - ext4_bg_size); 788 #endif 789 790 out: 791 return crc; 792 } 793 794 int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group) 795 { 796 if (ext2fs_has_group_desc_csum(fs) && 797 (ext2fs_bg_checksum(fs, group) != 798 ext2fs_group_desc_csum(fs, group))) 799 return 0; 800 801 return 1; 802 } 803 804 void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group) 805 { 806 if (!ext2fs_has_group_desc_csum(fs)) 807 return; 808 809 /* ext2fs_bg_checksum_set() sets the actual checksum field but 810 * does not calculate the checksum itself. */ 811 ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group)); 812 } 813 814 static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap, 815 __u32 inodes_per_grp, dgrp_t grp_no) 816 { 817 ext2_ino_t i, start_ino, end_ino; 818 819 start_ino = grp_no * inodes_per_grp + 1; 820 end_ino = start_ino + inodes_per_grp - 1; 821 822 for (i = end_ino; i >= start_ino; i--) { 823 if (ext2fs_fast_test_inode_bitmap2(bitmap, i)) 824 return i - start_ino + 1; 825 } 826 return inodes_per_grp; 827 } 828 829 /* update the bitmap flags, set the itable high watermark, and calculate 830 * checksums for the group descriptors */ 831 errcode_t ext2fs_set_gdt_csum(ext2_filsys fs) 832 { 833 struct ext2_super_block *sb = fs->super; 834 int dirty = 0; 835 dgrp_t i; 836 837 if (!fs->inode_map) 838 return EXT2_ET_NO_INODE_BITMAP; 839 840 if (!ext2fs_has_group_desc_csum(fs)) 841 return 0; 842 843 for (i = 0; i < fs->group_desc_count; i++) { 844 __u32 old_csum = ext2fs_bg_checksum(fs, i); 845 __u32 old_unused = ext2fs_bg_itable_unused(fs, i); 846 __u32 old_flags = ext2fs_bg_flags(fs, i); 847 __u32 old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i); 848 __u32 old_free_blocks_count = ext2fs_bg_free_blocks_count(fs, i); 849 850 if (old_free_blocks_count == sb->s_blocks_per_group && 851 i != fs->group_desc_count - 1) 852 ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT); 853 854 if (old_free_inodes_count == sb->s_inodes_per_group) { 855 ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT); 856 ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group); 857 } else { 858 int unused = 859 sb->s_inodes_per_group - 860 find_last_inode_ingrp(fs->inode_map, 861 sb->s_inodes_per_group, i); 862 863 ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT); 864 ext2fs_bg_itable_unused_set(fs, i, unused); 865 } 866 867 ext2fs_group_desc_csum_set(fs, i); 868 if (old_flags != ext2fs_bg_flags(fs, i)) 869 dirty = 1; 870 if (old_unused != ext2fs_bg_itable_unused(fs, i)) 871 dirty = 1; 872 if (old_csum != ext2fs_bg_checksum(fs, i)) 873 dirty = 1; 874 } 875 if (dirty) 876 ext2fs_mark_super_dirty(fs); 877 return 0; 878 } 879 880 #ifdef DEBUG 881 #include "e2p/e2p.h" 882 883 void print_csum(const char *msg, ext2_filsys fs, dgrp_t group) 884 { 885 __u16 crc1, crc2, crc3; 886 dgrp_t swabgroup; 887 struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc, 888 group); 889 size_t size = EXT2_DESC_SIZE(fs->super); 890 struct ext2_super_block *sb = fs->super; 891 int offset = offsetof(struct ext2_group_desc, bg_checksum); 892 #ifdef WORDS_BIGENDIAN 893 struct ext4_group_desc swabdesc; 894 struct ext2_group_desc *save_desc = desc; 895 const size_t ext4_bg_size = sizeof(struct ext4_group_desc); 896 size_t save_size = size; 897 #endif 898 899 #ifdef WORDS_BIGENDIAN 900 /* Have to swab back to little-endian to do the checksum */ 901 if (size > ext4_bg_size) 902 size = ext4_bg_size; 903 memcpy(&swabdesc, desc, size); 904 ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc); 905 desc = (struct ext2_group_desc *) &swabdesc; 906 907 swabgroup = ext2fs_swab32(group); 908 #else 909 swabgroup = group; 910 #endif 911 912 crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid)); 913 crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup)); 914 crc3 = ext2fs_crc16(crc2, desc, offset); 915 offset += sizeof(desc->bg_checksum); /* skip checksum */ 916 /* for checksum of struct ext4_group_desc do the rest...*/ 917 if (offset < size) 918 crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset); 919 #ifdef WORDS_BIGENDIAN 920 if (save_size > ext4_bg_size) 921 crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size, 922 save_size - ext4_bg_size); 923 #endif 924 925 printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n", 926 msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3, 927 ext2fs_group_desc_csum(fs, group)); 928 } 929 930 unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23, 931 0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb }; 932 933 int main(int argc, char **argv) 934 { 935 struct ext2_super_block param; 936 errcode_t retval; 937 ext2_filsys fs; 938 int i; 939 __u16 csum1, csum2, csum_known = 0xd3a4; 940 941 memset(¶m, 0, sizeof(param)); 942 ext2fs_blocks_count_set(¶m, 32768); 943 #if 0 944 param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT; 945 param.s_desc_size = 128; 946 csum_known = 0x5b6e; 947 #endif 948 949 retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, ¶m, 950 test_io_manager, &fs); 951 if (retval) { 952 com_err("setup", retval, 953 "While initializing filesystem"); 954 exit(1); 955 } 956 memcpy(fs->super->s_uuid, sb_uuid, 16); 957 fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM; 958 959 for (i=0; i < fs->group_desc_count; i++) { 960 ext2fs_block_bitmap_loc_set(fs, i, 124); 961 ext2fs_inode_bitmap_loc_set(fs, i, 125); 962 ext2fs_inode_table_loc_set(fs, i, 126); 963 ext2fs_bg_free_blocks_count_set(fs, i, 31119); 964 ext2fs_bg_free_inodes_count_set(fs, i, 15701); 965 ext2fs_bg_used_dirs_count_set(fs, i, 2); 966 ext2fs_bg_flags_zap(fs, i); 967 }; 968 969 csum1 = ext2fs_group_desc_csum(fs, 0); 970 print_csum("csum0000", fs, 0); 971 972 if (csum1 != csum_known) { 973 printf("checksum for group 0 should be %04x\n", csum_known); 974 exit(1); 975 } 976 csum2 = ext2fs_group_desc_csum(fs, 1); 977 print_csum("csum0001", fs, 1); 978 if (csum1 == csum2) { 979 printf("checksums for different groups shouldn't match\n"); 980 exit(1); 981 } 982 csum2 = ext2fs_group_desc_csum(fs, 2); 983 print_csum("csumffff", fs, 2); 984 if (csum1 == csum2) { 985 printf("checksums for different groups shouldn't match\n"); 986 exit(1); 987 } 988 ext2fs_bg_checksum_set(fs, 0, csum1); 989 csum2 = ext2fs_group_desc_csum(fs, 0); 990 print_csum("csum_set", fs, 0); 991 if (csum1 != csum2) { 992 printf("checksums should not depend on checksum field\n"); 993 exit(1); 994 } 995 if (!ext2fs_group_desc_csum_verify(fs, 0)) { 996 printf("checksums should verify against gd_checksum\n"); 997 exit(1); 998 } 999 memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid)); 1000 print_csum("new_uuid", fs, 0); 1001 if (ext2fs_group_desc_csum_verify(fs, 0) != 0) { 1002 printf("checksums for different filesystems shouldn't match\n"); 1003 exit(1); 1004 } 1005 csum1 = ext2fs_group_desc_csum(fs, 0); 1006 ext2fs_bg_checksum_set(fs, 0, csum1); 1007 print_csum("csum_new", fs, 0); 1008 ext2fs_bg_free_blocks_count_set(fs, 0, 1); 1009 csum2 = ext2fs_group_desc_csum(fs, 0); 1010 print_csum("csum_blk", fs, 0); 1011 if (csum1 == csum2) { 1012 printf("checksums for different data shouldn't match\n"); 1013 exit(1); 1014 } 1015 1016 return 0; 1017 } 1018 #endif 1019
