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Subject: Re: [PATCH 10/12] nvmet: Implement basic In-Band Authentication
To:     Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>
Cc:     Keith Busch <keith.busch@wdc.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        linux-nvme@lists.infradead.org, linux-crypto@vger.kernel.org
References: <20210910064322.67705-1-hare@suse.de>
 <20210910064322.67705-11-hare@suse.de>
 <79742bd7-a41c-0abc-e7de-8d222b146d02@grimberg.me>
 <c7739610-6d0b-7740-c339-b35ca5ae34e2@suse.de>
 <a2596777-25b2-f633-4b00-18b1a319c5c2@suse.de>
 <32d8f860-9fdb-606c-62b7-ad89837d8e71@grimberg.me>
 <2ccfb62a-d782-7bb2-4d41-6d1152851a4a@suse.de>
From:   Sagi Grimberg <sagi@grimberg.me>
Message-ID: <24d3ee65-83e7-c958-cd17-eb4351a8349c@grimberg.me>
Date:   Wed, 29 Sep 2021 01:36:47 +0300
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>>> Actually, having re-read the spec I'm not sure if the second path is
>>> correct.
>>> As per spec only the _host_ can trigger re-authentication. There is no
>>> provision for the controller to trigger re-authentication, and given
>>> that re-auth is a soft-state anyway (ie the current authentication
>>> stays valid until re-auth enters a final state) I _think_ we should be
>>> good with the current implementation, where we can change the
>>> controller keys
>>> via configfs, but they will only become active once the host triggers
>>> re-authentication.
>>
>> Agree, so the proposed addition is good with you?
>>
> Why would we need it?
> I do agree there's a bit missing for removing the old shash_tfm if there
> is a hash-id mismatch, but why would we need to reset the entire
> authentication?

Just need to update the new host dhchap_key from the host at this point
as the host is doing a re-authentication. I agree we don't need a big
hammer but we do need the re-authentication to not access old host
dhchap_key.