Re: [PATCH v2 03/14] nvmet: Implement CCR nvme command

Mohamed Khalfella
2026-02-04T17:52:52Z

On Wed 2026-02-04 01:55:18 +0100, Hannes Reinecke wrote:
> On 2/4/26 01:44, Mohamed Khalfella wrote:
> > On Wed 2026-02-04 01:38:44 +0100, Hannes Reinecke wrote:
> >> On 2/3/26 19:40, Mohamed Khalfella wrote:
> >>> On Tue 2026-02-03 04:19:50 +0100, Hannes Reinecke wrote:
> >>>> On 1/30/26 23:34, Mohamed Khalfella wrote:
> >>>>> @@ -1501,6 +1516,38 @@ struct nvmet_ctrl *nvmet_ctrl_find_get(const char *subsysnqn,
> >>>>> return ctrl;
> >>>>> }
> >>>>>
> >>>>> +struct nvmet_ctrl *nvmet_ctrl_find_get_ccr(struct nvmet_subsys *subsys,
> >>>>> + const char *hostnqn, u8 ciu,
> >>>>> + u16 cntlid, u64 cirn)
> >>>>> +{
> >>>>> + struct nvmet_ctrl *ctrl;
> >>>>> + bool found = false;
> >>>>> +
> >>>>> + mutex_lock(&subsys->lock);
> >>>>> + list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
> >>>>> + if (ctrl->cntlid != cntlid)
> >>>>> + continue;
> >>>>> + if (strncmp(ctrl->hostnqn, hostnqn, NVMF_NQN_SIZE))
> >>>>> + continue;
> >>>>> +
> >>>> Why do we compare the hostnqn here, too? To my understanding the host
> >>>> NQN is tied to the controller, so the controller ID should be sufficient
> >>>> here.
> >>>
> >>> We got cntlid from CCR nvme command and we do not trust the value sent by
> >>> the host. We check hostnqn to confirm that host is actually connected to
> >>> the impacted controller. A host should not be allowed to reset a
> >>> controller connected to another host.
> >>>
> >> Errm. So we're starting to not trust values in NVMe commands?
> >> That is a very slippery road.
> >> Ultimately it would require us to validate the cntlid on each
> >> admin command. Which we don't.
> >> And really there is no difference between CCR and any other
> >> admin command; you get even worse effects if you would assume
> >> a misdirected 'FORMAT' command.
> >>
> >> Please don't. Security is _not_ a concern here.
> >
> > I do not think the check hurts. If you say it is wrong I will delete it.
> >
> It's not 'wrong', It's inconsistent. The argument that the contents of
> an admin command may be wrong applies to _every_ admin command.
> Yet we never check on any of those commands.
> So I fail to see why this command requires special treatment.

Okay, I will delete this check.

>
> Cheers,
>
> Hannes
> --
> Dr. Hannes Reinecke Kernel Storage Architect
> hare@suse.de +49 911 74053 688
> SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
> HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich