On Fri 01-04-16 10:39:56, Ted Tso wrote:
> On Tue, Mar 29, 2016 at 06:11:43PM +0200, Jan Kara wrote:
> > Currently we oopsed when Q_GETNEXTQUOTA got called when quota was
> > disabled. Properly check whether quota is enabled for the filesystem
> > before calling into quota format handler.
> >
> > diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> > index ba827daea5a0..ff21980d0119 100644
> > --- a/fs/quota/dquot.c
> > +++ b/fs/quota/dquot.c
> > @@ -2047,11 +2047,20 @@ int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
> > struct quota_info *dqopt = sb_dqopt(sb);
> > int err;
> >
> > - if (!dqopt->ops[qid->type]->get_next_id)
> > - return -ENOSYS;
> > + mutex_lock(&dqopt->dqonoff_mutex);
> > + if (!sb_has_quota_active(sb, qid->type)) {
> > + err = -ESRCH;
> > + goto out;
> > + }
> > + if (!dqopt->ops[qid->type]->get_next_id) {
> > + err = -ENOSYS;
> > + goto out;
> > + }
>
> Don't you also have to test if dqopt->ops[qid->type] is NULL? e.g.,
> if the quota inode hasn't been loaded for that quota type?
Well, we first setup ->ops[type], then load quota inode, and only after
that enable flags which sb_has_quota_active() is checking so I don't see a
need for additional checking of dqopt->ops[qid->type].
> Also, I notice you have this queued on the for_next branch and not the
> for_linus branch. I was hoping you could push this to Linus sooner
> than the next merge cycle, since this is (a) making my testing hard,
> and (b) it makes it easy for an attacker to crash the system. For
> similar reasons, perhaps this should have a cc: stable@xxxxxxxxxxxxxxx
> tag?
The problematic code was merged in this merge window so no point to cc
stable. I want to push the fix to Linus for rc3 (likely today or tomorrow)
so you should be able to get that soon. Sorry for complications.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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