On Fri 18 Feb 2022 at 11:36, Greg KH greg@kroah.com wrote:
On Wed, Feb 09, 2022 at 01:40:52PM -0500, Sasha Levin wrote:
From: Su Yue l@damenly.su
[ Upstream commit ea1d1ca4025ac6c075709f549f9aa036b5b6597d ]
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: Sasha Levin sashal@kernel.org
fs/btrfs/tree-checker.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index d4a3a56726aa8..4a5ee516845f7 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -947,6 +947,7 @@ 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(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_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 (btrfs_device_id(leaf, ditem) != key->offset) { dev_item_err(leaf, slot,
-- 2.34.1
This adds a build warning, showing that the backport is not correct, so I'll go drop this :(
And the warning is ======================================================================== arch/x86/kernel/head_64.o: warning: objtool: .text+0x5: unreachable instruction fs/btrfs/tree-checker.c: In function \342\200\230check_dev_item\342\200\231: fs/btrfs/tree-checker.c:950:53: warning: passing argument 2 of \342\200\230btrfs_item_size\342\200\231 makes pointer from integer without a cast [-Wint-conversion] 950 | const u32 item_size = btrfs_item_size(leaf, slot); | ^~~~ | | | int In file included from fs/btrfs/tree-checker.c:21: fs/btrfs/ctree.h:1474:48: note: expected \342\200\230const struct btrfs_item *\342\200\231 but argument is of type \342\200\230int\342\200\231 1474 | const type *s) \ | ~~~~~~~~~~~~^ fs/btrfs/ctree.h:1833:1: note: in expansion of macro \342\200\230BTRFS_SETGET_FUNCS\342\200\231 1833 | BTRFS_SETGET_FUNCS(item_size, struct btrfs_item, size, 32); | ^~~~~~~~~~~~~~~~~~ ========================================================================
The upstream patchset[1] merged in 5.17-rc1, changed second parameter of btrfs_item_size() from btrfs_item * to int directly. So yes, the backport is wrong.
I'm not familiar with stable backport progress. Should I file a patch using btrfs_item *? Or just drop it?
The patch is related to 0c982944af27d131d3b74242f3528169f66950ad but I wonder why the 0c98294 is not selected automatically.
Thanks.
[1]: https://patchwork.kernel.org/project/linux-btrfs/cover/cover.1634842475.git.... -- Su
thanks,
greg k-h