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Date: Tue, 16 Apr 2024 08:39:28 -0500
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From: Joachim Vandersmissen <git@jvdsn.com>
Subject: Re: [PATCH 2/2] certs: Guard RSA signature verification self-test
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org, David Howells <dhowells@redhat.com>,
 Simo Sorce <simo@redhat.com>, Stephan Mueller <smueller@chronox.de>
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 <20240416032347.72663-2-git@jvdsn.com> <Zh494tFvPQhxJ8j4@gondor.apana.org.au>
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Hi Herbert,

On 4/16/24 3:59 AM, Herbert Xu wrote:
> On Mon, Apr 15, 2024 at 10:23:47PM -0500, Joachim Vandersmissen wrote:
>> Currently it is possible to configure the kernel (albeit in a very
>> contrived manner) such that CRYPTO_RSA is not set, yet
>> FIPS_SIGNATURE_SELFTEST is set. This would cause a false kernel panic
>> when executing the RSA PKCS#7 self-test. Guard against this by
>> introducing a compile-time check.
>>
>> Signed-off-by: Joachim Vandersmissen <git@jvdsn.com>
> The usual way to handle this is to add a select to the Kconfig file.

I did consider that initially, but I was unsure if this was the right 
path. From a conceptual standpoint, this module doesn't need the RSA (or 
ECDSA) functionality. If the algorithm is not present, it would be 
perfectly valid for the module to do nothing. However, I'm not opposed 
to removing the current check and adding the select to the Kconfig.

If I add a `select CRYPTO_RSA` to FIPS_SIGNATURE_SELFTEST, do you think 
I should do something similar for ECDSA as well (considering the other 
patch in this series)?

>
> Thanks,