From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 6924C1A08B6 for ; Mon, 1 Dec 2014 04:09:25 +1100 (AEDT) From: Julia Lawall To: Herbert Xu Subject: [PATCH 6/8 v2] crypto: replace memset by memzero_explicit Date: Sun, 30 Nov 2014 18:03:47 +0100 Message-Id: <1417367029-32762-7-git-send-email-Julia.Lawall@lip6.fr> In-Reply-To: <1417367029-32762-1-git-send-email-Julia.Lawall@lip6.fr> References: <1417367029-32762-1-git-send-email-Julia.Lawall@lip6.fr> Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Mackerras , linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "David S. Miller" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Julia Lawall Memset on a local variable may be removed when it is called just before the variable goes out of scope. Using memzero_explicit defeats this optimization. A simplified version of the semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // @@ identifier x; type T; @@ { ... when any T x[...]; ... when any when exists - memset + memzero_explicit (x, -0, ...) ... when != x when strict } // This change was suggested by Daniel Borkmann Signed-off-by: Julia Lawall --- Daniel Borkmann suggested that these patches could go through Herbert Xu's cryptodev tree. v2: fixed email address arch/powerpc/crypto/sha1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/crypto/sha1.c b/arch/powerpc/crypto/sha1.c index 0f88c7b..d3feba5 100644 --- a/arch/powerpc/crypto/sha1.c +++ b/arch/powerpc/crypto/sha1.c @@ -66,7 +66,7 @@ static int sha1_update(struct shash_desc *desc, const u8 *data, src = data + done; } while (done + 63 < len); - memset(temp, 0, sizeof(temp)); + memzero_explicit(temp, sizeof(temp)); partial = 0; } memcpy(sctx->buffer + partial, src, len - done);