From: Su Yue <l@damenly.su>
Date: Fri, 21 Jan 2022 09:33:35 +0000 (+0800)
Subject: btrfs: tree-checker: check item_size for dev_item
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b80fbc20f33489dd810edfc52343e3c0f4b2403a;p=linux.git

btrfs: tree-checker: check item_size for dev_item

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>
---

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 692d372a54cd0..51382d2be3d44 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -965,6 +965,7 @@ static int check_dev_item(struct extent_buffer *leaf,
 			  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_buffer *leaf,
 			     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,