linux-kernel - Re: [PATCH v3 1/5] crypto: Use memzero

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Message-ID: <20201023205059.GD27708@gondor.apana.org.au>
Date:   Sat, 24 Oct 2020 07:50:59 +1100
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     "David S. Miller" <davem@...emloft.net>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        Eric Biggers <ebiggers@...nel.org>,
        David Laight <David.Laight@...lab.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/5] crypto: Use memzero_explicit() for clearing state

On Fri, Oct 23, 2020 at 03:21:59PM -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.

Please only convert sha256 and not everything.

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