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Date: Fri, 26 Jan 2024 13:58:52 +0800
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Joachim Vandersmissen <git@jvdsn.com>
Cc: linux-crypto@vger.kernel.org
Subject: Re: [PATCH] crypto: rsa - restrict plaintext/ciphertext values more
 in FIPS mode
Message-ID: <ZbNKHGDiGOyIB5+S@gondor.apana.org.au>
References: <20240121194901.344206-1-git@jvdsn.com>
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On Sun, Jan 21, 2024 at 01:49:00PM -0600, Joachim Vandersmissen wrote:
>
>  static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
>  {
> +	/* For FIPS, SP 800-56Br2, Section 7.1.1 requires 1 < m < n - 1 */
> +	if (fips_enabled && rsa_check_payload_fips(m, key->n))
> +		return -EINVAL;
> +
>  	/* (1) Validate 0 <= m < n */
>  	if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
>  		return -EINVAL;

I think this check makes sense in general, so why not simply
replace the second check above with the new check?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt