linux-kernel - Re: [PATCH v2 1/6] crypto: Use memzero

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Message-ID: <20201022043633.GD857@sol.localdomain>
Date:   Wed, 21 Oct 2020 21:36:33 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        David Laight <David.Laight@...lab.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/6] crypto: Use memzero_explicit() for clearing state

On Tue, Oct 20, 2020 at 04:39:52PM -0400, Arvind Sankar wrote:
> Without the barrier_data() inside memzero_explicit(), the compiler may
> optimize away the state-clearing if it can tell that the state is not
> used afterwards. At least in lib/crypto/sha256.c:__sha256_final(), the
> function can get inlined into sha256(), in which case the memset is
> optimized away.
> 
> Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>

Reviewed-by: Eric Biggers <ebiggers@...gle.com>

Maybe get the one in arch/arm64/crypto/sha3-ce-glue.c too?

- Eric