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Subject: Re: [PATCH 03/11] crypto/ffdhe: Finite Field DH Ephemeral Parameters
To:     Sagi Grimberg <sagi@grimberg.me>, Christoph Hellwig <hch@lst.de>
Cc:     Keith Busch <keith.busch@wdc.com>, linux-nvme@lists.infradead.org,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        linux-crypto@vger.kernel.org
References: <20210716110428.9727-1-hare@suse.de>
 <20210716110428.9727-4-hare@suse.de>
 <3f9473c3-12c6-71c0-0744-34ea2a8a8c99@grimberg.me>
From:   Hannes Reinecke <hare@suse.de>
Message-ID: <73e065db-7200-1409-2bd1-5a06df4404a0@suse.de>
Date:   Sat, 17 Jul 2021 15:57:33 +0200
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On 7/17/21 8:14 AM, Sagi Grimberg wrote:
>> Add helper functions to generaten Finite Field DH Ephemeral Parameters as
>> specified in RFC 7919.
>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>   crypto/Kconfig         |   8 +
>>   crypto/Makefile        |   1 +
>>   crypto/ffdhe_helper.c  | 877 +++++++++++++++++++++++++++++++++++++++++
>>   include/crypto/ffdhe.h |  24 ++
>>   4 files changed, 910 insertions(+)
>>   create mode 100644 crypto/ffdhe_helper.c
>>   create mode 100644 include/crypto/ffdhe.h
>>
>> diff --git a/crypto/Kconfig b/crypto/Kconfig
>> index ca3b02dcbbfa..1bea506ba56f 100644
>> --- a/crypto/Kconfig
>> +++ b/crypto/Kconfig
>> @@ -231,6 +231,14 @@ config CRYPTO_DH
>>       help
>>         Generic implementation of the Diffie-Hellman algorithm.
>> +config CRYPTO_FFDHE
>> +    tristate "Finite Field DH (RFC 7919) ephemeral parameters"
> 
> I'd stick with "Diffie-Hellman" in the tristate.
> 

Ok.

>> +    select CRYPTO_DH
>> +    select CRYPTO_KPP
>> +    select CRYPTO_RNG_DEFAULT
>> +    help
>> +      Generic implementation of the Finite Field DH algorithm
> 
> Diffie-Hellman algorithm
> And not sure I'd call it algorithm implementation, but rather a
> helper but maybe something like:
> Finite Field Diffie-Hellman ephemeral parameters helper implementation
> 

Wasn't sure how to call it myself; as stated I'm not a security expert.

>> +
>>   config CRYPTO_ECC
>>       tristate
>> diff --git a/crypto/Makefile b/crypto/Makefile
>> index 10526d4559b8..d3bc79fba23f 100644
>> --- a/crypto/Makefile
>> +++ b/crypto/Makefile
>> @@ -177,6 +177,7 @@ obj-$(CONFIG_CRYPTO_OFB) += ofb.o
>>   obj-$(CONFIG_CRYPTO_ECC) += ecc.o
>>   obj-$(CONFIG_CRYPTO_ESSIV) += essiv.o
>>   obj-$(CONFIG_CRYPTO_CURVE25519) += curve25519-generic.o
>> +obj-$(CONFIG_CRYPTO_FFDHE) += ffdhe_helper.o
>>   ecdh_generic-y += ecdh.o
>>   ecdh_generic-y += ecdh_helper.o
>> diff --git a/crypto/ffdhe_helper.c b/crypto/ffdhe_helper.c
>> new file mode 100644
>> index 000000000000..dc023e30c4e5
>> --- /dev/null
>> +++ b/crypto/ffdhe_helper.c
>> @@ -0,0 +1,877 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Finite Field DH Ephemeral Parameters (RFC 7919)
>> + *
>> + * Copyright (c) 2021, Hannes Reinecke, SUSE Software Products
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <crypto/internal/kpp.h>
>> +#include <crypto/kpp.h>
>> +#include <crypto/dh.h>
>> +#include <linux/mpi.h>
>> +
>> +/*
>> + * ffdhe2048 generator (g), modulus (p) and group size (q)
> 
> Maybe worth to refer exactly the source of these parameters
> in the comment body (rfc section/appendix).
> 

Sure. These actually are copies from RFC 7919, so will be adding a 
reference to it.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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