APPLIED: [SRU][M][PATCH 0/1] CVE-2024-26704

[Roxana Nicolescu]

On 19/04/2024 23:28, Bethany Jamison wrote:
> [Impact]
>
>   In the Linux kernel, the following vulnerability has been resolved:
>
>   ext4: fix double-free of blocks due to wrong extents moved_len
>
>   In ext4_move_extents(), moved_len is only updated when all moves are
>   successfully executed, and only discards orig_inode and donor_inode
>   preallocations when moved_len is not zero. When the loop fails to exit
>   after successfully moving some extents, moved_len is not updated and
>   remains at 0, so it does not discard the preallocations.
>
>   If the moved extents overlap with the preallocated extents, the
>   overlapped extents are freed twice in ext4_mb_release_inode_pa() and
>   ext4_process_freed_data() (as described in commit 94d7c16cbbbd ("ext4:
>   Fix double-free of blocks with EXT4_IOC_MOVE_EXT")), and bb_free is
>   incremented twice. Hence when trim is executed, a zero-division bug is
>   triggered in mb_update_avg_fragment_size() because bb_free is not zero
>   and bb_fragments is zero.
>
>   Therefore, update move_len after each extent move to avoid the issue.
>
> [Fix]
>
> Mantic:	Clean cherry-pick from linux-6.6.y
> Jammy:	pending
> Focal:	pending
> Bionic:	fix sent to esm ML
> Xenial:	fix sent to esm ML
> Trusty:	not-affected
>
> [Test Case]
>
> Compile and boot tested.
>
> [Where problems could occur]
>
> This fix affects those who use the Ext4 file system, and an issue with
> this fix would be visable to the user via a system crash.
>
> Baokun Li (1):
>    ext4: fix double-free of blocks due to wrong extents moved_len
>
>   fs/ext4/move_extent.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
>
It was already applied from upstream. I just added the CVE no to the 
commit.