1 /* 2 * Copyright (C) Qu Wenruo 2017. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program. 15 */ 16 17 /* 18 * The module is used to catch unexpected/corrupted tree block data. 19 * Such behavior can be caused either by a fuzzed image or bugs. 20 * 21 * The objective is to do leaf/node validation checks when tree block is read 22 * from disk, and check *every* possible member, so other code won't 23 * need to checking them again. 24 * 25 * Due to the potential and unwanted damage, every checker needs to be 26 * carefully reviewed otherwise so it does not prevent mount of valid images. 27 */ 28 29 #include "ctree.h" 30 #include "tree-checker.h" 31 #include "disk-io.h" 32 #include "compression.h" 33 34 /* 35 * Error message should follow the following format: 36 * corrupt <type>: <identifier>, <reason>[, <bad_value>] 37 * 38 * @type: leaf or node 39 * @identifier: the necessary info to locate the leaf/node. 40 * It's recommened to decode key.objecitd/offset if it's 41 * meaningful. 42 * @reason: describe the error 43 * @bad_value: optional, it's recommened to output bad value and its 44 * expected value (range). 45 * 46 * Since comma is used to separate the components, only space is allowed 47 * inside each component. 48 */ 49 50 /* 51 * Append generic "corrupt leaf/node root=%llu block=%llu slot=%d: " to @fmt. 52 * Allows callers to customize the output. 53 */ 54 __printf(4, 5) 55 static void generic_err(const struct btrfs_root *root, 56 const struct extent_buffer *eb, int slot, 57 const char *fmt, ...) 58 { 59 struct va_format vaf; 60 va_list args; 61 62 va_start(args, fmt); 63 64 vaf.fmt = fmt; 65 vaf.va = &args; 66 67 btrfs_crit(root->fs_info, 68 "corrupt %s: root=%llu block=%llu slot=%d, %pV", 69 btrfs_header_level(eb) == 0 ? "leaf" : "node", 70 root->objectid, btrfs_header_bytenr(eb), slot, &vaf); 71 va_end(args); 72 } 73 74 /* 75 * Customized reporter for extent data item, since its key objectid and 76 * offset has its own meaning. 77 */ 78 __printf(4, 5) 79 static void file_extent_err(const struct btrfs_root *root, 80 const struct extent_buffer *eb, int slot, 81 const char *fmt, ...) 82 { 83 struct btrfs_key key; 84 struct va_format vaf; 85 va_list args; 86 87 btrfs_item_key_to_cpu(eb, &key, slot); 88 va_start(args, fmt); 89 90 vaf.fmt = fmt; 91 vaf.va = &args; 92 93 btrfs_crit(root->fs_info, 94 "corrupt %s: root=%llu block=%llu slot=%d ino=%llu file_offset=%llu, %pV", 95 btrfs_header_level(eb) == 0 ? "leaf" : "node", root->objectid, 96 btrfs_header_bytenr(eb), slot, key.objectid, key.offset, &vaf); 97 va_end(args); 98 } 99 100 /* 101 * Return 0 if the btrfs_file_extent_##name is aligned to @alignment 102 * Else return 1 103 */ 104 #define CHECK_FE_ALIGNED(root, leaf, slot, fi, name, alignment) \ 105 ({ \ 106 if (!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))) \ 107 file_extent_err((root), (leaf), (slot), \ 108 "invalid %s for file extent, have %llu, should be aligned to %u", \ 109 (#name), btrfs_file_extent_##name((leaf), (fi)), \ 110 (alignment)); \ 111 (!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))); \ 112 }) 113 114 static int check_extent_data_item(struct btrfs_root *root, 115 struct extent_buffer *leaf, 116 struct btrfs_key *key, int slot) 117 { 118 struct btrfs_file_extent_item *fi; 119 u32 sectorsize = root->fs_info->sectorsize; 120 u32 item_size = btrfs_item_size_nr(leaf, slot); 121 122 if (!IS_ALIGNED(key->offset, sectorsize)) { 123 file_extent_err(root, leaf, slot, 124 "unaligned file_offset for file extent, have %llu should be aligned to %u", 125 key->offset, sectorsize); 126 return -EUCLEAN; 127 } 128 129 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); 130 131 if (btrfs_file_extent_type(leaf, fi) > BTRFS_FILE_EXTENT_TYPES) { 132 file_extent_err(root, leaf, slot, 133 "invalid type for file extent, have %u expect range [0, %u]", 134 btrfs_file_extent_type(leaf, fi), 135 BTRFS_FILE_EXTENT_TYPES); 136 return -EUCLEAN; 137 } 138 139 /* 140 * Support for new compression/encrption must introduce incompat flag, 141 * and must be caught in open_ctree(). 142 */ 143 if (btrfs_file_extent_compression(leaf, fi) > BTRFS_COMPRESS_TYPES) { 144 file_extent_err(root, leaf, slot, 145 "invalid compression for file extent, have %u expect range [0, %u]", 146 btrfs_file_extent_compression(leaf, fi), 147 BTRFS_COMPRESS_TYPES); 148 return -EUCLEAN; 149 } 150 if (btrfs_file_extent_encryption(leaf, fi)) { 151 file_extent_err(root, leaf, slot, 152 "invalid encryption for file extent, have %u expect 0", 153 btrfs_file_extent_encryption(leaf, fi)); 154 return -EUCLEAN; 155 } 156 if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) { 157 /* Inline extent must have 0 as key offset */ 158 if (key->offset) { 159 file_extent_err(root, leaf, slot, 160 "invalid file_offset for inline file extent, have %llu expect 0", 161 key->offset); 162 return -EUCLEAN; 163 } 164 165 /* Compressed inline extent has no on-disk size, skip it */ 166 if (btrfs_file_extent_compression(leaf, fi) != 167 BTRFS_COMPRESS_NONE) 168 return 0; 169 170 /* Uncompressed inline extent size must match item size */ 171 if (item_size != BTRFS_FILE_EXTENT_INLINE_DATA_START + 172 btrfs_file_extent_ram_bytes(leaf, fi)) { 173 file_extent_err(root, leaf, slot, 174 "invalid ram_bytes for uncompressed inline extent, have %u expect %llu", 175 item_size, BTRFS_FILE_EXTENT_INLINE_DATA_START + 176 btrfs_file_extent_ram_bytes(leaf, fi)); 177 return -EUCLEAN; 178 } 179 return 0; 180 } 181 182 /* Regular or preallocated extent has fixed item size */ 183 if (item_size != sizeof(*fi)) { 184 file_extent_err(root, leaf, slot, 185 "invalid item size for reg/prealloc file extent, have %u expect %zu", 186 item_size, sizeof(*fi)); 187 return -EUCLEAN; 188 } 189 if (CHECK_FE_ALIGNED(root, leaf, slot, fi, ram_bytes, sectorsize) || 190 CHECK_FE_ALIGNED(root, leaf, slot, fi, disk_bytenr, sectorsize) || 191 CHECK_FE_ALIGNED(root, leaf, slot, fi, disk_num_bytes, sectorsize) || 192 CHECK_FE_ALIGNED(root, leaf, slot, fi, offset, sectorsize) || 193 CHECK_FE_ALIGNED(root, leaf, slot, fi, num_bytes, sectorsize)) 194 return -EUCLEAN; 195 return 0; 196 } 197 198 static int check_csum_item(struct btrfs_root *root, struct extent_buffer *leaf, 199 struct btrfs_key *key, int slot) 200 { 201 u32 sectorsize = root->fs_info->sectorsize; 202 u32 csumsize = btrfs_super_csum_size(root->fs_info->super_copy); 203 204 if (key->objectid != BTRFS_EXTENT_CSUM_OBJECTID) { 205 generic_err(root, leaf, slot, 206 "invalid key objectid for csum item, have %llu expect %llu", 207 key->objectid, BTRFS_EXTENT_CSUM_OBJECTID); 208 return -EUCLEAN; 209 } 210 if (!IS_ALIGNED(key->offset, sectorsize)) { 211 generic_err(root, leaf, slot, 212 "unaligned key offset for csum item, have %llu should be aligned to %u", 213 key->offset, sectorsize); 214 return -EUCLEAN; 215 } 216 if (!IS_ALIGNED(btrfs_item_size_nr(leaf, slot), csumsize)) { 217 generic_err(root, leaf, slot, 218 "unaligned item size for csum item, have %u should be aligned to %u", 219 btrfs_item_size_nr(leaf, slot), csumsize); 220 return -EUCLEAN; 221 } 222 return 0; 223 } 224 225 /* 226 * Common point to switch the item-specific validation. 227 */ 228 static int check_leaf_item(struct btrfs_root *root, 229 struct extent_buffer *leaf, 230 struct btrfs_key *key, int slot) 231 { 232 int ret = 0; 233 234 switch (key->type) { 235 case BTRFS_EXTENT_DATA_KEY: 236 ret = check_extent_data_item(root, leaf, key, slot); 237 break; 238 case BTRFS_EXTENT_CSUM_KEY: 239 ret = check_csum_item(root, leaf, key, slot); 240 break; 241 } 242 return ret; 243 } 244 245 int btrfs_check_leaf(struct btrfs_root *root, struct extent_buffer *leaf) 246 { 247 struct btrfs_fs_info *fs_info = root->fs_info; 248 /* No valid key type is 0, so all key should be larger than this key */ 249 struct btrfs_key prev_key = {0, 0, 0}; 250 struct btrfs_key key; 251 u32 nritems = btrfs_header_nritems(leaf); 252 int slot; 253 254 /* 255 * Extent buffers from a relocation tree have a owner field that 256 * corresponds to the subvolume tree they are based on. So just from an 257 * extent buffer alone we can not find out what is the id of the 258 * corresponding subvolume tree, so we can not figure out if the extent 259 * buffer corresponds to the root of the relocation tree or not. So 260 * skip this check for relocation trees. 261 */ 262 if (nritems == 0 && !btrfs_header_flag(leaf, BTRFS_HEADER_FLAG_RELOC)) { 263 struct btrfs_root *check_root; 264 265 key.objectid = btrfs_header_owner(leaf); 266 key.type = BTRFS_ROOT_ITEM_KEY; 267 key.offset = (u64)-1; 268 269 check_root = btrfs_get_fs_root(fs_info, &key, false); 270 /* 271 * The only reason we also check NULL here is that during 272 * open_ctree() some roots has not yet been set up. 273 */ 274 if (!IS_ERR_OR_NULL(check_root)) { 275 struct extent_buffer *eb; 276 277 eb = btrfs_root_node(check_root); 278 /* if leaf is the root, then it's fine */ 279 if (leaf != eb) { 280 generic_err(check_root, leaf, 0, 281 "invalid nritems, have %u should not be 0 for non-root leaf", 282 nritems); 283 free_extent_buffer(eb); 284 return -EUCLEAN; 285 } 286 free_extent_buffer(eb); 287 } 288 return 0; 289 } 290 291 if (nritems == 0) 292 return 0; 293 294 /* 295 * Check the following things to make sure this is a good leaf, and 296 * leaf users won't need to bother with similar sanity checks: 297 * 298 * 1) key ordering 299 * 2) item offset and size 300 * No overlap, no hole, all inside the leaf. 301 * 3) item content 302 * If possible, do comprehensive sanity check. 303 * NOTE: All checks must only rely on the item data itself. 304 */ 305 for (slot = 0; slot < nritems; slot++) { 306 u32 item_end_expected; 307 int ret; 308 309 btrfs_item_key_to_cpu(leaf, &key, slot); 310 311 /* Make sure the keys are in the right order */ 312 if (btrfs_comp_cpu_keys(&prev_key, &key) >= 0) { 313 generic_err(root, leaf, slot, 314 "bad key order, prev (%llu %u %llu) current (%llu %u %llu)", 315 prev_key.objectid, prev_key.type, 316 prev_key.offset, key.objectid, key.type, 317 key.offset); 318 return -EUCLEAN; 319 } 320 321 /* 322 * Make sure the offset and ends are right, remember that the 323 * item data starts at the end of the leaf and grows towards the 324 * front. 325 */ 326 if (slot == 0) 327 item_end_expected = BTRFS_LEAF_DATA_SIZE(fs_info); 328 else 329 item_end_expected = btrfs_item_offset_nr(leaf, 330 slot - 1); 331 if (btrfs_item_end_nr(leaf, slot) != item_end_expected) { 332 generic_err(root, leaf, slot, 333 "unexpected item end, have %u expect %u", 334 btrfs_item_end_nr(leaf, slot), 335 item_end_expected); 336 return -EUCLEAN; 337 } 338 339 /* 340 * Check to make sure that we don't point outside of the leaf, 341 * just in case all the items are consistent to each other, but 342 * all point outside of the leaf. 343 */ 344 if (btrfs_item_end_nr(leaf, slot) > 345 BTRFS_LEAF_DATA_SIZE(fs_info)) { 346 generic_err(root, leaf, slot, 347 "slot end outside of leaf, have %u expect range [0, %u]", 348 btrfs_item_end_nr(leaf, slot), 349 BTRFS_LEAF_DATA_SIZE(fs_info)); 350 return -EUCLEAN; 351 } 352 353 /* Also check if the item pointer overlaps with btrfs item. */ 354 if (btrfs_item_nr_offset(slot) + sizeof(struct btrfs_item) > 355 btrfs_item_ptr_offset(leaf, slot)) { 356 generic_err(root, leaf, slot, 357 "slot overlaps with its data, item end %lu data start %lu", 358 btrfs_item_nr_offset(slot) + 359 sizeof(struct btrfs_item), 360 btrfs_item_ptr_offset(leaf, slot)); 361 return -EUCLEAN; 362 } 363 364 /* Check if the item size and content meet other criteria */ 365 ret = check_leaf_item(root, leaf, &key, slot); 366 if (ret < 0) 367 return ret; 368 369 prev_key.objectid = key.objectid; 370 prev_key.type = key.type; 371 prev_key.offset = key.offset; 372 } 373 374 return 0; 375 } 376 377 int btrfs_check_node(struct btrfs_root *root, struct extent_buffer *node) 378 { 379 unsigned long nr = btrfs_header_nritems(node); 380 struct btrfs_key key, next_key; 381 int slot; 382 u64 bytenr; 383 int ret = 0; 384 385 if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root->fs_info)) { 386 btrfs_crit(root->fs_info, 387 "corrupt node: root=%llu block=%llu, nritems too %s, have %lu expect range [1,%u]", 388 root->objectid, node->start, 389 nr == 0 ? "small" : "large", nr, 390 BTRFS_NODEPTRS_PER_BLOCK(root->fs_info)); 391 return -EUCLEAN; 392 } 393 394 for (slot = 0; slot < nr - 1; slot++) { 395 bytenr = btrfs_node_blockptr(node, slot); 396 btrfs_node_key_to_cpu(node, &key, slot); 397 btrfs_node_key_to_cpu(node, &next_key, slot + 1); 398 399 if (!bytenr) { 400 generic_err(root, node, slot, 401 "invalid NULL node pointer"); 402 ret = -EUCLEAN; 403 goto out; 404 } 405 if (!IS_ALIGNED(bytenr, root->fs_info->sectorsize)) { 406 generic_err(root, node, slot, 407 "unaligned pointer, have %llu should be aligned to %u", 408 bytenr, root->fs_info->sectorsize); 409 ret = -EUCLEAN; 410 goto out; 411 } 412 413 if (btrfs_comp_cpu_keys(&key, &next_key) >= 0) { 414 generic_err(root, node, slot, 415 "bad key order, current (%llu %u %llu) next (%llu %u %llu)", 416 key.objectid, key.type, key.offset, 417 next_key.objectid, next_key.type, 418 next_key.offset); 419 ret = -EUCLEAN; 420 goto out; 421 } 422 } 423 out: 424 return ret; 425 } 426