[PATCH 5.10 03/80] btrfs: tree-checker: check item_size for dev_item

Greg Kroah-Hartman
2022-02-28T17:40:55Z

From: Su Yue <l@damenly.su>

commit ea1d1ca4025ac6c075709f549f9aa036b5b6597d upstream.

Check item size before accessing the device item to avoid out of bound
access, similar to inode_item check.

Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/tree-checker.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -947,6 +947,7 @@ static int check_dev_item(struct extent_
struct btrfs_key *key, int slot)
{
struct btrfs_dev_item *ditem;
+ const u32 item_size = btrfs_item_size_nr(leaf, slot);

if (key->objectid != BTRFS_DEV_ITEMS_OBJECTID) {
dev_item_err(leaf, slot,
@@ -954,6 +955,13 @@ static int check_dev_item(struct extent_
key->objectid, BTRFS_DEV_ITEMS_OBJECTID);
return -EUCLEAN;
}
+
+ if (unlikely(item_size != sizeof(*ditem))) {
+ dev_item_err(leaf, slot, "invalid item size: has %u expect %zu",
+ item_size, sizeof(*ditem));
+ return -EUCLEAN;
+ }
+
ditem = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item);
if (btrfs_device_id(leaf, ditem) != key->offset) {
dev_item_err(leaf, slot,