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SubjectRe: [PATCH] ext4: fix possible use after free in ext4_quota_enable
On Mon 26-11-18 11:21:06, Pan Bian wrote:
> The function frees qf_inode via iput but then pass qf_inode to
> lockdep_set_quota_inode on the failure path. This may result in a
> use-after-free bug. The patch frees df_inode only when it is never used.
>
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> Fixes: daf647d2dd5("ext4: add lockdep annotations for i_data_sem")

Thanks for the fix! The patch looks good. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/ext4/super.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 53ff6c2..35689eb 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5690,9 +5690,9 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
> qf_inode->i_flags |= S_NOQUOTA;
> lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
> err = dquot_enable(qf_inode, type, format_id, flags);
> - iput(qf_inode);
> if (err)
> lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
> + iput(qf_inode);
>
> return err;
> }
> --
> 2.7.4
>
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR

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