Re: [PATCH v3 13/18] crypto: rsa-psspad: Get signature parameters from a given signature

From: Varad Gautam <varad.gautam@suse.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org, dhowells@redhat.com,
	davem@davemloft.net, vt@altlinux.org,
	tianjia.zhang@linux.alibaba.com, keyrings@vger.kernel.org,
	linux-kernel@vger.kernel.org, jarkko@kernel.org
Subject: Re: [PATCH v3 13/18] crypto: rsa-psspad: Get signature parameters from a given signature
Date: Mon, 5 Jul 2021 11:39:10 +0200	[thread overview]
Message-ID: <9af846ac-ad96-f59e-d89e-0c75bb75416c@suse.com> (raw)
In-Reply-To: <20210514104535.q4zjtshxroruvoz3@gondor.apana.org.au>

Hi Herbert,

On 5/14/21 12:45 PM, Herbert Xu wrote:
> On Tue, Apr 20, 2021 at 01:41:18PM +0200, Varad Gautam wrote:
>>
>> +static int psspad_set_sig_params(struct crypto_akcipher *tfm,
>> +				 const void *sig,
>> +				 unsigned int siglen)
>> +{
>> +	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
>> +	struct rsapad_inst_ctx *ictx = akcipher_instance_ctx(inst);
>> +	const struct public_key_signature *s = sig;
>> +
>> +	if (!sig)
>> +		return -EINVAL;
>> +
>> +	ictx->salt_len = s->salt_length;
>> +	ictx->mgf_hash_algo = s->mgf_hash_algo;
> 
> Is there any reason why this couldn't be embedded into the key
> instead?

Sorry about the delay, do you mean setting these as part of
rsapad_set_pub_key()? 

The same pubkey can be used to verify both PSS and PKCSv1.5 style signatures,
so I don't see the signature params (salt length / mgf hash) being a part
of the pkey state.

Thanks,
Varad

> 
> Thanks,
> 

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