This is a note to let you know that I've just added the patch titled dm btree: add a defensive bounds check to insert_at() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-btree-add-a-defensive-bounds-check-to-insert_at.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 592c3f8827a2ca30bba60554dbeb891575e4f2e9 Author: Joe Thornber <ejt@xxxxxxxxxx> Date: Fri Dec 10 13:44:13 2021 +0000 dm btree: add a defensive bounds check to insert_at() [ Upstream commit 85bca3c05b6cca31625437eedf2060e846c4bbad ] Corrupt metadata could trigger an out of bounds write. Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c index ef6e78d45d5b8..ee3e63aa864bf 100644 --- a/drivers/md/persistent-data/dm-btree.c +++ b/drivers/md/persistent-data/dm-btree.c @@ -83,14 +83,16 @@ void inc_children(struct dm_transaction_manager *tm, struct btree_node *n, } static int insert_at(size_t value_size, struct btree_node *node, unsigned index, - uint64_t key, void *value) - __dm_written_to_disk(value) + uint64_t key, void *value) + __dm_written_to_disk(value) { uint32_t nr_entries = le32_to_cpu(node->header.nr_entries); + uint32_t max_entries = le32_to_cpu(node->header.max_entries); __le64 key_le = cpu_to_le64(key); if (index > nr_entries || - index >= le32_to_cpu(node->header.max_entries)) { + index >= max_entries || + nr_entries >= max_entries) { DMERR("too many entries in btree node for insert"); __dm_unbless_for_disk(value); return -ENOMEM;