Re: [PATCH v5 4/6] ubifs: don't trigger assertion on invalid no-key filename

[Eric Biggers]

On Mon, Jan 20, 2020 at 02:31:59PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
> 
> If userspace provides an invalid fscrypt no-key filename which encodes a
> hash value with any of the UBIFS node type bits set (i.e. the high 3
> bits), gracefully report ENOENT rather than triggering ubifs_assert().
> 
> Test case with kvm-xfstests shell:
> 
>     . fs/ubifs/config
>     . ~/xfstests/common/encrypt
>     dev=$(__blkdev_to_ubi_volume /dev/vdc)
>     ubiupdatevol $dev -t
>     mount $dev /mnt -t ubifs
>     mkdir /mnt/edir
>     xfs_io -c set_encpolicy /mnt/edir
>     rm /mnt/edir/_,,,,,DAAAAAAAAAAAAAAAAAAAAAAAAAA
> 
> With the bug, the following assertion fails on the 'rm' command:
> 
>     [   19.066048] UBIFS error (ubi0:0 pid 379): ubifs_assert_failed: UBIFS assert failed: !(hash & ~UBIFS_S_KEY_HASH_MASK), in fs/ubifs/key.h:170
> 
> Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.10+
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>

Richard, can you review the two UBIFS patches in this series, and if you're okay
with them, provide Acked-by's so that we can take them through the fscrypt tree?
They don't conflict with anything currently in the UBIFS tree.

Thanks!

- Eric