linux-kernel - Re: [PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

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Message-ID: <1383095144.12439.41.camel@joe-AO722>
Date:	Tue, 29 Oct 2013 18:05:44 -0700
From:	Joe Perches <joe@...ches.com>
To:	Peter Huewe <peterhuewe@....de>
Cc:	Ashley Lai <ashley@...leylai.com>, Rajiv Andrade <mail@...jiv.net>,
	Marcel Selhorst <tpmdd@...horst.net>,
	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Xiaoyan Zhang <xiaoyan.zhang@...el.com>,
	Gang Wei <gang.wei@...el.com>, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

On Wed, 2013-10-30 at 01:40 +0100, Peter Huewe wrote:
> strcmp does return the difference between two strings not only -1,0,1
> consequently
>  if (strcmp (a,b) == -1)
> might lead to taking the wrong branch
> 
> -> compare with <= instead.

lib/string.c:strcmp returns only -1,0,1
so that's what the arch versions should do too.
However, arch implementations do vary...

fyi: using
	if (strcmp(foo, bar) < 0)
is canonical.

There are no existing <= -1 uses.


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