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SubjectRe: [Patch] quota: do not leak info to user-space
On Fri 10-05-13 17:24:33, Cong Wang wrote:
> From: Cong Wang <amwang@redhat.com>
>
> There is a hole in struct fs_quota_stat, so we have to
> zero the struct on stack before copying it to user-space.
>
> Cc: Jan Kara <jack@suse.cz>
> Signed-off-by: Cong Wang <amwang@redhat.com>
Good point. I've merged the patch.

BTW for XFS folks: The structure definition looks somewhat odd (unaligned
definition of qs_flags, qs_uquota starts only at 32-bit boundary although
it has 64-bit fields in it) and I wouldn't be surprised if it needed compat
wrapper for 32-bit apps on some architectures...

Honza
>
> ---
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index c7314f1..2b0c182 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -211,6 +211,7 @@ static int quota_getxstate(struct super_block *sb, void __user *addr)
>
> if (!sb->s_qcop->get_xstate)
> return -ENOSYS;
> + memset(&fqs, 0, sizeof(fqs));
> ret = sb->s_qcop->get_xstate(sb, &fqs);
> if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
> return -EFAULT;
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR


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