[PATCH 06/17] nvme: add nvme_auth_derive_tls_psk()

[Hannes Reinecke]

On 4/7/24 23:04, Sagi Grimberg wrote:
> 
> 
> On 18/03/2024 17:03, Hannes Reinecke wrote:
>> From: Hannes Reinecke <hare at suse.de>
>>
>> Add a function to derive the TLS PSK as specified TP8018.
>>
>> Signed-off-by: Hannes Reinecke <hare at suse.de>
>> ---
>>   drivers/nvme/common/auth.c | 71 ++++++++++++++++++++++++++++++++++++++
>>   include/linux/nvme-auth.h  |  1 +
>>   2 files changed, 72 insertions(+)
>>
>> diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
>> index f56f08a4461e..90d525afc240 100644
>> --- a/drivers/nvme/common/auth.c
>> +++ b/drivers/nvme/common/auth.c
>> @@ -652,5 +652,76 @@ u8 *nvme_auth_generate_digest(u8 hmac_id, u8 
>> *psk, size_t psk_len,
>>   }
>>   EXPORT_SYMBOL_GPL(nvme_auth_generate_digest);
>> +u8 *nvme_auth_derive_tls_psk(int hmac_id, u8 *psk, size_t psk_len, u8 
>> *psk_digest)
>> +{
> 
> Same comment here.
> Can you please add a description of the derivation process in a function 
> comment?
> It is not trivial for me to follow.
> 
Sure, will do.

>> +    struct crypto_shash *hmac_tfm;
>> +    const char *hmac_name;
>> +    const char *psk_prefix = "tls13 nvme-tls-psk";
>> +    size_t info_len, prk_len;
>> +    char *info;
>> +    unsigned char *prk, *tls_key;
>> +    int ret;
>> +
>> +    hmac_name = nvme_auth_hmac_name(hmac_id);
>> +    if (!hmac_name) {
>> +        pr_warn("%s: invalid hash algoritm %d\n",
>> +            __func__, hmac_id);
>> +        return ERR_PTR(-EINVAL);
>> +    }
>> +    if (hmac_id == NVME_AUTH_HASH_SHA512) {
>> +        pr_warn("%s: unsupported hash algorithm %s\n",
>> +            __func__, hmac_name);
>> +        return ERR_PTR(-EINVAL);
>> +    }
>> +
>> +    hmac_tfm = crypto_alloc_shash(hmac_name, 0, 0);
>> +    if (IS_ERR(hmac_tfm))
>> +        return (u8 *)hmac_tfm;
>> +
>> +    prk_len = crypto_shash_digestsize(hmac_tfm);
>> +    prk = kzalloc(prk_len, GFP_KERNEL);
> 
> What does prk stand for?
> 
That's from the spec. It'll be referred to in the function
description.

Cheers,

Hannes