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

[Chris Mason]

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



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