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Date: Sat, 11 Jul 2026 17:17:32 +0200
From: Lukas Wunner <lukas@wunner.de>
To: David Gall <david.ccm.gall@googlemail.com>
Cc: Ignat Korchagin <ignat@linux.win>, Greg KH <gregkh@linuxfoundation.org>,
	Eric Biggers <ebiggers@kernel.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] crypto: rsassa-pkcs1: use constant-time comparison for
 digest and signature verification
Message-ID: <alJejMW5JwNQWw7C@wunner.de>
References: <alEr_e-G0L2nxxv-@fudgebox>
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In-Reply-To: <alInuM5TquLTv5QE@fudgebox>

On Sat, Jul 11, 2026 at 01:23:36PM +0200, David Gall wrote:
> That said, this function [rsassa_pkcs1_verify()] already uses
> crypto_memneq() for the hash-prefix check a few lines above.
> I'd argue for consistency it's worth using it for the digest
> comparison too.

I'd prefer the other way round, i.e. to use memcmp() for the hash_prefix
comparison.

Thanks,

Lukas