From 268fcde8576b96cffa5f57cbdae146d56d1a069d Mon Sep 17 00:00:00 2001 From: Joseph Qi Date: Tue, 1 Sep 2026 20:52:20 +0800 Subject: [PATCH] ocfs2: validate suballoc slot and bit of xattr and dir index blocks ocfs2_validate_xattr_block() and ocfs2_validate_dx_root() do not validate xb_suballoc_slot, xb_suballoc_bit, dr_suballoc_slot and dr_suballoc_bit at all. Since xattr blocks and dir index root blocks are allocated from a per-slot suballocator at runtime, their suballoc slots must be within range and their suballoc bits must fit in a block group bitmap. Otherwise a corrupted image can carry an out-of-range slot. When the xattr block or dir index is removed, ocfs2_xattr_block_remove() or ocfs2_dx_dir_remove_index() passes the unvalidated slot to ocfs2_get_system_file_inode() and get_local_system_inode() will either hit BUG_ON(slot == OCFS2_INVALID_SLOT) or compute an out-of-bounds index into the local_system_inodes array. Similarly an oversized suballoc bit will error out the filesystem in _ocfs2_free_suballoc_bits(). Furthermore ocfs2_validate_dx_root() does not verify dr_blkno against the physical block number like the extent and xattr block validators do, so a misplaced dir index root block can pass validation. Reject misplaced dir index root blocks, out-of-range suballoc slots and oversized suballoc bits during validation. Link: https://lore.kernel.org/20260901125221.1634686-4-joseph.qi@linux.alibaba.com Signed-off-by: Joseph Qi Signed-off-by: Andrew Morton Cc: Changwei Ge Cc: Heming Zhao Cc: Joel Becker Cc: Jun Piao Cc: Junxiao Bi Cc: Mark Fasheh --- fs/ocfs2/dir.c | 35 +++++++++++++++++++++++++++++++++++ fs/ocfs2/xattr.c | 25 +++++++++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index 0075e1624310..6bb6aa133f01 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -605,6 +605,41 @@ static int ocfs2_validate_dx_root(struct super_block *sb, goto bail; } + if (le64_to_cpu(dx_root->dr_blkno) != bh->b_blocknr) { + ret = ocfs2_error(sb, + "Dir Index Root # %llu has an invalid dr_blkno of %llu\n", + (unsigned long long)bh->b_blocknr, + (unsigned long long)le64_to_cpu(dx_root->dr_blkno)); + goto bail; + } + + /* + * Dir index root blocks are allocated from a per-slot suballocator, + * so the slot must be in range. Otherwise removing the index passes + * it to get_local_system_inode(), which hits BUG_ON() for + * OCFS2_INVALID_SLOT or computes an out-of-bounds index otherwise. + */ + if ((u32)le16_to_cpu(dx_root->dr_suballoc_slot) >= OCFS2_SB(sb)->max_slots) { + ret = ocfs2_error(sb, + "Dir Index Root # %llu has invalid dr_suballoc_slot %u\n", + (unsigned long long)le64_to_cpu(dx_root->dr_blkno), + le16_to_cpu(dx_root->dr_suballoc_slot)); + goto bail; + } + + /* + * Similarly the suballoc bit must fit in a block group bitmap. + * Otherwise removing the index will pass the oversized bit to + * _ocfs2_free_suballoc_bits() and trigger ocfs2_error() there. + */ + if (le16_to_cpu(dx_root->dr_suballoc_bit) >= ocfs2_suballoc_bits_per_block(sb)) { + ret = ocfs2_error(sb, + "Dir Index Root # %llu has invalid dr_suballoc_bit %u\n", + (unsigned long long)le64_to_cpu(dx_root->dr_blkno), + le16_to_cpu(dx_root->dr_suballoc_bit)); + goto bail; + } + if (!(dx_root->dr_flags & OCFS2_DX_FLAG_INLINE)) { struct ocfs2_extent_list *el = &dx_root->dr_list; diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 740d4bb3890f..e27f5f925df5 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -532,6 +532,31 @@ static int ocfs2_validate_xattr_block(struct super_block *sb, le32_to_cpu(xb->xb_fs_generation)); } + /* + * Xattr blocks are allocated from a per-slot suballocator, so the + * slot must be in range. Otherwise freeing the block passes it to + * get_local_system_inode(), which hits BUG_ON() for + * OCFS2_INVALID_SLOT or computes an out-of-bounds index otherwise. + */ + if ((u32)le16_to_cpu(xb->xb_suballoc_slot) >= OCFS2_SB(sb)->max_slots) { + return ocfs2_error(sb, + "Extended attribute block #%llu has an invalid xb_suballoc_slot of %u\n", + (unsigned long long)bh->b_blocknr, + le16_to_cpu(xb->xb_suballoc_slot)); + } + + /* + * Similarly the suballoc bit must fit in a block group bitmap. + * Otherwise freeing the block will pass the oversized bit to + * _ocfs2_free_suballoc_bits() and trigger ocfs2_error() there. + */ + if (le16_to_cpu(xb->xb_suballoc_bit) >= ocfs2_suballoc_bits_per_block(sb)) { + return ocfs2_error(sb, + "Extended attribute block #%llu has an invalid xb_suballoc_bit of %u\n", + (unsigned long long)bh->b_blocknr, + le16_to_cpu(xb->xb_suballoc_bit)); + } + if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) { size_t region_offset = offsetof(struct ocfs2_xattr_block, xb_attrs.xb_header);