Re: [PATCH] Btrfs:__add_inode_ref: out of bounds memory read when looking for extended ref.

From: Chris Mason
Date: Tue Mar 03 2015 - 10:36:10 EST




On Tue, Mar 3, 2015 at 10:31 AM, Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx> wrote:
Improper arithmetics when calculting the address of the extended ref could
lead to an out of bounds memory read and kernel panic.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
---
fs/btrfs/tree-log.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git fs/btrfs/tree-log.c fs/btrfs/tree-log.c
index 9a37f8b..c5b8ba3 100644
--- fs/btrfs/tree-log.c
+++ fs/btrfs/tree-log.c
@@ -1012,7 +1012,7 @@ again:
base = btrfs_item_ptr_offset(leaf, path->slots[0]);

while (cur_offset < item_size) {
- extref = (struct btrfs_inode_extref *)base + cur_offset;
+ extref = (struct btrfs_inode_extref *)(base + cur_offset);

victim_name_len = btrfs_inode_extref_name_len(leaf, extref);


Thanks, this goes back to 3.7+ (Mark's original extref code). I'll tag for stable and add Dave's reviewed by:

Reviewed-by: David Sterba <dsterba@xxxxxxx>

-chris



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/