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 @@ -965,6 +965,7 @@ 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 (unlikely(key->objectid != BTRFS_DEV_ITEMS_OBJECTID)) { dev_item_err(leaf, slot, @@ -972,6 +973,13 @@ 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 (unlikely(btrfs_device_id(leaf, ditem) != key->offset)) { dev_item_err(leaf, slot,