From: Herbert Xu <herbert@gondor.apana.org.au>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>,
"David S. Miller" <davem@davemloft.net>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
David Laight <David.Laight@aculab.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/6] crypto: Use memzero_explicit() for clearing state
Date: Sat, 24 Oct 2020 07:45:36 +1100 [thread overview]
Message-ID: <20201023204536.GB27708@gondor.apana.org.au> (raw)
In-Reply-To: <20201023155604.GA3908702@gmail.com>
On Fri, Oct 23, 2020 at 08:56:04AM -0700, Eric Biggers wrote:
>
> When clearing memory because "it may be sensitive" rather than "it's needed for
> the code to behave correctly", I think it's best to use memzero_explicit() to
> make the intent clear, even if it seems that memset() is sufficient. Also keep
> in mind that support for compiling the kernel with LTO (link-time optimization)
> is being worked on (and some people already do it), which results in more code
> being optimized out.
The rule up until now has been that we only use memzero_explicit for
stack variables. At this point please don't convert anything else
as it will cause too much churn.
If LTO did arrive we should do a global conversion.
Cheers,
--
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
next prev parent reply other threads:[~2020-10-23 20:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 20:39 [PATCH v2 0/6] crypto: lib/sha256 - cleanup/optimization Arvind Sankar
2020-10-20 20:39 ` [PATCH v2 1/6] crypto: Use memzero_explicit() for clearing state Arvind Sankar
2020-10-22 4:36 ` Eric Biggers
2020-10-23 15:39 ` Arvind Sankar
2020-10-23 15:56 ` Eric Biggers
2020-10-23 20:45 ` Herbert Xu [this message]
2020-10-23 21:53 ` Eric Biggers
2020-10-29 7:00 ` Herbert Xu
2020-10-20 20:39 ` [PATCH v2 2/6] crypto: lib/sha256 - Don't clear temporary variables Arvind Sankar
2020-10-22 4:58 ` Eric Biggers
2020-10-23 3:17 ` Arvind Sankar
2020-10-20 20:39 ` [PATCH v2 3/6] crypto: lib/sha256 - Clear W[] in sha256_update() instead of sha256_transform() Arvind Sankar
2020-10-22 4:59 ` Eric Biggers
2020-10-20 20:39 ` [PATCH v2 4/6] crypto: lib/sha256 - Unroll SHA256 loop 8 times intead of 64 Arvind Sankar
2020-10-22 5:02 ` Eric Biggers
2020-10-23 3:12 ` Arvind Sankar
2020-10-23 3:16 ` Herbert Xu
2020-10-20 20:39 ` [PATCH v2 5/6] crypto: lib/sha256 - Unroll LOAD and BLEND loops Arvind Sankar
2020-10-22 5:02 ` Eric Biggers
2020-10-20 20:39 ` [PATCH v2 6/6] crypto: lib/sha - Combine round constants and message schedule Arvind Sankar
2020-10-20 21:36 ` David Laight
2020-10-21 15:16 ` Arvind Sankar
2020-10-22 4:34 ` Eric Biggers
2020-10-22 8:20 ` David Laight
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