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If anyone has any objections, please let me know. ------------------ From: Doruk Tan Ozturk [ Upstream commit bc70726ddad53c7e9a9a85915bf2415b0d4f42f9 ] ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and signature of an indexed-directory block before it reaches higher-level callers, but neither validator bounds the ocfs2_dx_entry_list counts against the capacity of the block that holds them. ocfs2_dx_dir_search() then walks for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++) dx_entry = &entry_list->de_entries[i]; over de_num_used entries with no bounds check. entry_list is either dx_leaf->dl_list (from ocfs2_read_dx_leaf) or, for an inline root, dx_root->dr_entries. A crafted on-disk image can set de_num_used (and de_count, which is the __counted_by_le() bound of de_entries) to 0xffff and make the walk read far past the end of the 4KB metadata block, giving a slab out-of-bounds read reachable from any path lookup, stat() or open() on an indexed directory once the image is mounted. Commit 775c17386a6f ("ocfs2: validate dx_root extent list fields during block read") already bounds dr_list for the non-inline dx_root, but left the inline dr_entries path and the dx_leaf dl_list unchecked. Add the same read-time validation for both entry lists: de_count must equal the capacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and de_num_used must not exceed de_count, rejecting corrupted metadata with -EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry array. de_count is always written as exactly the block capacity when a leaf or inline root is formatted, so the equality check does not reject any valid image. Found by 0sec automated security-research tooling (https://0sec.ai). Link: https://lore.kernel.org/20260713205625.92391-1-doruk@0sec.ai Fixes: 9b7895efac90 ("ocfs2: Add a name indexed b-tree to directory inodes") Fixes: 4ed8a6bb083b ("ocfs2: Store dir index records inline") Assisted-by: 0sec:claude-opus-4-8 Signed-off-by: Doruk Tan Ozturk Reviewed-by: Joseph Qi Cc: Joel Becker Cc: Kees Cook Cc: Mark Fasheh Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/ocfs2/dir.c | 45 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index 0b673df36f597..717362c3ee313 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -611,6 +611,28 @@ static int ocfs2_validate_dx_root(struct super_block *sb, le16_to_cpu(el->l_count)); goto bail; } + } else { + struct ocfs2_dx_entry_list *dl_list = &dx_root->dr_entries; + + if (le16_to_cpu(dl_list->de_count) != + ocfs2_dx_entries_per_root(sb)) { + ret = ocfs2_error(sb, + "Dir Index Root # %llu has invalid de_count %u (expected %u)\n", + (unsigned long long)le64_to_cpu(dx_root->dr_blkno), + le16_to_cpu(dl_list->de_count), + ocfs2_dx_entries_per_root(sb)); + goto bail; + } + + if (le16_to_cpu(dl_list->de_num_used) > + le16_to_cpu(dl_list->de_count)) { + ret = ocfs2_error(sb, + "Dir Index Root # %llu has invalid de_num_used %u (de_count %u)\n", + (unsigned long long)le64_to_cpu(dx_root->dr_blkno), + le16_to_cpu(dl_list->de_num_used), + le16_to_cpu(dl_list->de_count)); + goto bail; + } } bail: @@ -650,10 +672,25 @@ static int ocfs2_validate_dx_leaf(struct super_block *sb, return ret; } - if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) { - ret = ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n", - 7, dx_leaf->dl_signature); - } + if (!OCFS2_IS_VALID_DX_LEAF(dx_leaf)) + return ocfs2_error(sb, "Dir Index Leaf has bad signature %.*s\n", + 7, dx_leaf->dl_signature); + + if (le16_to_cpu(dx_leaf->dl_list.de_count) != + ocfs2_dx_entries_per_leaf(sb)) + return ocfs2_error(sb, + "Dir Index Leaf # %llu has invalid de_count %u (expected %u)\n", + (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno), + le16_to_cpu(dx_leaf->dl_list.de_count), + ocfs2_dx_entries_per_leaf(sb)); + + if (le16_to_cpu(dx_leaf->dl_list.de_num_used) > + le16_to_cpu(dx_leaf->dl_list.de_count)) + return ocfs2_error(sb, + "Dir Index Leaf # %llu has invalid de_num_used %u (de_count %u)\n", + (unsigned long long)le64_to_cpu(dx_leaf->dl_blkno), + le16_to_cpu(dx_leaf->dl_list.de_num_used), + le16_to_cpu(dx_leaf->dl_list.de_count)); return ret; } -- 2.53.0