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

Mohamed Khalfella
2026-02-04T00:44:23Z

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.

>
> 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