Subject: Re: [PATCHv5 00/12] nvme: In-band authentication support
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     Christoph Hellwig <hch@lst.de>, Keith Busch <keith.busch@wdc.com>,
        linux-nvme@lists.infradead.org,
        Herbert Xu <herbert@gondor.apana.org.au>,
        David Miller <davem@davemloft.net>,
        linux-crypto@vger.kernel.org
References: <20211112125928.97318-1-hare@suse.de>
 <74db7c77-7cbf-4bc9-1c80-e7c42acaea64@grimberg.me>
 <f67ca46e-f421-33f7-da8b-ff6e47acf8c2@suse.de>
 <8553266f-005c-f947-4737-2108cb7062d1@grimberg.me>
 <a7363853-05af-9d7f-4d6f-b02ec756ce6b@suse.de>
 <50095ec8-3825-efa5-98bb-76b0f0fdc21e@grimberg.me>
From:   Hannes Reinecke <hare@suse.de>
Message-ID: <31088486-0134-0dad-b052-32fd3ce2d1cf@suse.de>
Date:   Tue, 16 Nov 2021 11:23:45 +0100
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On 11/16/21 11:18 AM, Sagi Grimberg wrote:
> 
>>>>>> - Transform secret with correct hmac algorithm
>>>>>
>>>>> Is that what I reported last time? Can you perhaps
>>>>> point me to the exact patch that fixes this?
>>>>
>>>> Well, no, not really; the patch itself got squashed in the main
>>>> patches.
>>>> But problem here was that the key transformation from section 8.13.5.7
>>>> had been using the hash algorithm from the initial challenge, not the
>>>> one specified in the key itself.
>>>> This lead to decoding errors when using a key with a different length
>>>> than the hash algorithm.
>>>
>>> That is exactly what I reported, changing the key length leads to
>>> authentication errors.
>>
>> Right-o. So it should be sorted then.
> 
> Hannes, was the issue on the host side or the controller side?
> 
The issue was actually on the host side.

> I'm a little lost into what was the actual fix...

The basic fix was this:

@@ -927,13 +944,17 @@ static int nvme_auth_dhchap_host_response(struct
nvme_ctrl
 *ctrl,

        if (!chap->host_response) {
                chap->host_response =
nvme_auth_transform_key(ctrl->dhchap_key,
-                                       ctrl->dhchap_key_len, chap->hash_id,
+                                       ctrl->dhchap_key_len,
+                                       ctrl->dhchap_key_hash,
                                        ctrl->opts->host->nqn);
                if (IS_ERR(chap->host_response)) {
                        ret = PTR_ERR(chap->host_response);
                        chap->host_response = NULL;
                        return ret;
                }


(minus the linebreaks, of course).
'chap->hash_id' is the hash selected by the initial negotiation, which
is wrong as we should have used the hash function selected by the key
itself.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer