Re: [PATCH V2] fs: jfs: fix shift-out-of-bounds in dbDiscardAG

[Dave Kleikamp]

Applied.

Thanks,
Shaggy

On 10/25/22 10:20AM, Hoi Pok Wu wrote:
> This should be applied to most URSAN bugs found recently by syzbot,
> by guarding the dbMount. As syzbot feeding rubbish into the bmap
> descriptor.
>
> Signed-off-by: Hoi Pok Wu <wuhoipok@xxxxxxxxx>
> ---
> V1->2: guarding the corrupted data structure from dbMount instead
>   fs/jfs/jfs_dmap.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
> index e1cbfbb60303..765838578a72 100644
> --- a/fs/jfs/jfs_dmap.c
> +++ b/fs/jfs/jfs_dmap.c
> @@ -198,6 +198,11 @@ int dbMount(struct inode *ipbmap)
>   		goto err_release_metapage;
>   	}
>   
> +	if (((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) {
> +		err = -EINVAL;
> +		goto err_release_metapage;
> +	}
> +
>   	for (i = 0; i < MAXAG; i++)
>   		bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
>   	bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);