This patch will introduce ROOT_ITEM check, which includes: - Key->objectid and key->offset check Currently only some easy check, e.g. 0 as rootid is invalid. - Item size check Root item size is fixed. - Generation checks Generation, v2_generaetion and last_snapshot should not pass super generation + 1 - Level and alignment check Level should be in [0, 7], and bytenr must be aligned to sector size. - Flags check Link: https://bugzilla.kernel.org/show_bug.cgi?id=203261 Signed-off-by: Qu Wenruo <wqu@xxxxxxxx> --- fs/btrfs/tree-checker.c | 92 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index a4c7f7ed8490..71bbbce3076d 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -810,6 +810,95 @@ static int check_inode_item(struct extent_buffer *leaf, return 0; } +static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key, + int slot) +{ + struct btrfs_fs_info *fs_info = leaf->fs_info; + struct btrfs_root_item ri; + u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY | + BTRFS_ROOT_SUBVOL_DEAD; + + /* No Such Tree id*/ + if (key->objectid == 0) { + generic_err(leaf, slot, "invalid root id 0"); + return -EUCLEAN; + } + + /* + * Some older kernel may create ROOT_ITEM with non-zero offset, + * so here we only check offset for reloc tree whose key->offset + * must be a valid tree. + */ + if (key->objectid == BTRFS_TREE_RELOC_OBJECTID && key->offset == 0) { + generic_err(leaf, slot, "invalid root id 0 for reloc tree"); + return -EUCLEAN; + } + + if (btrfs_item_size_nr(leaf, slot) != sizeof(ri)) { + generic_err(leaf, slot, + "invalid root item size, have %u expect %lu", + btrfs_item_size_nr(leaf, slot), sizeof(ri)); + } + + read_extent_buffer(leaf, &ri, btrfs_item_ptr_offset(leaf, slot), + sizeof(ri)); + + /* Generateion related */ + if (btrfs_root_generation(&ri) > + btrfs_super_generation(fs_info->super_copy) + 1) { + generic_err(leaf, slot, + "invalid root generaetion, have %llu expect (0, %llu]", + btrfs_root_generation(&ri), + btrfs_super_generation(fs_info->super_copy) + 1); + return -EUCLEAN; + } + if (btrfs_root_generation_v2(&ri) > + btrfs_super_generation(fs_info->super_copy) + 1) { + generic_err(leaf, slot, + "invalid root v2 generaetion, have %llu expect (0, %llu]", + btrfs_root_generation_v2(&ri), + btrfs_super_generation(fs_info->super_copy) + 1); + return -EUCLEAN; + } + if (btrfs_root_last_snapshot(&ri) > + btrfs_super_generation(fs_info->super_copy) + 1) { + generic_err(leaf, slot, + "invalid root last_snapshot, have %llu expect (0, %llu]", + btrfs_root_last_snapshot(&ri), + btrfs_super_generation(fs_info->super_copy) + 1); + return -EUCLEAN; + } + + /* Alignment and level check */ + if (!IS_ALIGNED(btrfs_root_bytenr(&ri), fs_info->sectorsize)) { + generic_err(leaf, slot, + "invalid root bytenr, have %llu expect to be aligned to %u", + btrfs_root_bytenr(&ri), fs_info->sectorsize); + return -EUCLEAN; + } + if (btrfs_root_level(&ri) >= BTRFS_MAX_LEVEL) { + generic_err(leaf, slot, + "invalid root level, have %u expect [0, %u]", + btrfs_root_level(&ri), BTRFS_MAX_LEVEL - 1); + return -EUCLEAN; + } + if (ri.drop_level >= BTRFS_MAX_LEVEL) { + generic_err(leaf, slot, + "invalid root level, have %u expect [0, %u]", + ri.drop_level, BTRFS_MAX_LEVEL - 1); + return -EUCLEAN; + } + + /* Flags check */ + if (btrfs_root_flags(&ri) & ~valid_root_flags) { + generic_err(leaf, slot, + "invalid root flags, have 0x%llx expect mask 0x%llu", + btrfs_root_flags(&ri), valid_root_flags); + return -EUCLEAN; + } + return 0; +} + /* * Common point to switch the item-specific validation. */ @@ -845,6 +934,9 @@ static int check_leaf_item(struct extent_buffer *leaf, case BTRFS_INODE_ITEM_KEY: ret = check_inode_item(leaf, key, slot); break; + case BTRFS_ROOT_ITEM_KEY: + ret = check_root_item(leaf, key, slot); + break; } return ret; } -- 2.22.0
