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From: daw@cs.berkeley.edu (David Wagner)
Newsgroups: isaac.lists.linux-kernel
Subject: Re: [PATCH 3/4] security/selinux: decrement sizeof size in strncmp
Date: Thu, 12 Nov 2009 18:28:03 +0000 (UTC)
Organization: University of California, Berkeley
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References: <Pine.LNX.4.64.0911120849050.16627@ask.diku.dk> <20091112145314.GA24682@us.ibm.com> <Pine.LNX.4.64.0911121556390.19779@ask.diku.dk> <4AFC3620.2020809@schaufler-ca.com>
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Casey Schaufler  wrote:
> I strongly suggest that this is not what is wanted.
>     strcmp(x,y)
> and
>     strncmp(x,y,sizeof(y))
>
> are functionally equivalent and strcmp has a bad reputation in
> the security community because it is associated with potential
> buffer overrun issues.

It does?  Hmm, I don't recall hearing of this bad reputation for strcmp().
Is there a justification for why such a reputation would be deserved?
We're not talking strcpy() here.  strcmp() is fine as long as its
arguments are properly '\0'-terminated; given that, it doesn't introduce
any new buffer overrun risks.