Subject: Re: [PATCH 07/12] nvme: Implement In-Band authentication
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.org>,
        linux-crypto@vger.kernel.org
References: <20211123123801.73197-1-hare@suse.de>
 <20211123123801.73197-8-hare@suse.de>
 <ffd1519b-1f39-898a-be7f-5d9db7377ad1@grimberg.me>
From:   Hannes Reinecke <hare@suse.de>
Message-ID: <33461345-668f-112c-9552-9930714ab609@suse.de>
Date:   Tue, 23 Nov 2021 14:30:53 +0100
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On 11/23/21 2:11 PM, Sagi Grimberg wrote:
> 
>> +int nvme_auth_generate_key(struct nvme_ctrl *ctrl, u8 *secret, bool
>> set_ctrl)
> 
> Didn't we agree to pass the key pointer? i.e.
> int nvme_auth_generate_key(struct nvme_dhchap_key **key, u8 *secret)
> 
Ah. That's what you had in mind.
Why, of course we can do that.

>> +{
>> +    struct nvme_dhchap_key *key;
>> +    u8 key_hash;
>> +
>> +    if (!secret)
>> +        return 0;
>> +
>> +    if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1)
>> +        return -EINVAL;
>> +
>> +    /* Pass in the secret without the 'DHHC-1:XX:' prefix */
>> +    key = nvme_auth_extract_key(secret + 10, key_hash);
>> +    if (IS_ERR(key)) {
>> +        dev_dbg(ctrl->device, "failed to extract key, error %ld\n",
>> +            PTR_ERR(key));
> 
> The print here is slightly redundant - you already have prints inside
> nvme_auth_extract_key already.
> 
Yeah; I really need to go through the code and remove the redundant
messages. Especially on the error paths.

>> +        return PTR_ERR(key);
>> +    }
>> +
> 
> Then we instead just do:
>     *key = key;
> 
>> +    if (set_ctrl)
>> +        ctrl->ctrl_key = key;
>> +    else
>> +        ctrl->host_key = key;
>> +
>> +    return 0;
>> +}
> 
> ...
> 
>> +EXPORT_SYMBOL_GPL(nvme_auth_generate_key);
>> diff --git a/drivers/nvme/host/auth.h b/drivers/nvme/host/auth.h
>> new file mode 100644
>> index 000000000000..16e3d893d54a
>> --- /dev/null
>> +++ b/drivers/nvme/host/auth.h
>> @@ -0,0 +1,33 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2021 Hannes Reinecke, SUSE Software Solutions
>> + */
>> +
>> +#ifndef _NVME_AUTH_H
>> +#define _NVME_AUTH_H
>> +
>> +#include <crypto/kpp.h>
>> +
>> +struct nvme_dhchap_key {
>> +    u8 *key;
>> +    size_t key_len;
>> +    u8 key_hash;
> 
> Why not just name it len and hash? don't think the key_
> prefix is useful...

True.
Will do so.

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