linux-kernel - Re: [PATCH] Use memzero_explicit to clear local buffers

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Message-ID: <20150106205454.GA22067@gondor.apana.org.au>
Date:	Wed, 7 Jan 2015 07:54:54 +1100
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Giel van Schijndel <me@...tis.eu>
Cc:	linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"maintainer:X86 ARCHITECTURE..." <x86@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Steve French <sfrench@...ba.org>,
	Rahul Bedarkar <rahulbedarkar89@...il.com>,
	Thomas Pugliese <thomas.pugliese@...il.com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Julia Lawall <Julia.Lawall@...6.fr>,
	"open list:CRYPTO API" <linux-crypto@...r.kernel.org>,
	"open list:CERTIFIED WIRELES..." <linux-usb@...r.kernel.org>,
	"open list:COMMON INTERNET F..." <linux-cifs@...r.kernel.org>,
	"moderated list:COMMON INTERNET F..." 
	<samba-technical@...ts.samba.org>,
	Daniel Borkmann <dborkman@...hat.com>
Subject: Re: [PATCH] Use memzero_explicit to clear local buffers

On Tue, Jan 06, 2015 at 08:42:26PM +0100, Giel van Schijndel wrote:
> 
> Question: are you sure the compiler won't optimize the call to memset(0)
> way if it's immediately followed by kfree()?

Yes it won't be optimised away.  However, you could use kzfree.

> Another actually does change a stack-allocated buffer, I'll split that
> one off right away.

OK.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
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