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

Hannes Reinecke
2026-02-04T00:55:26Z

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.

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
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