Subject: Re: [RFC] globmatch() helper function
From: Steven Rostedt <srostedt@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Tejun Heo <tj@kernel.org>, George Spelvin <linux@horizon.com>,
        peterz@infradead.org, linux-kernel@vger.kernel.org
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Organization: Red Hat
Date: Wed, 17 Dec 2008 11:54:32 -0500
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On Wed, 2008-12-17 at 17:51 +0100, Andi Kleen wrote:
> > OK, lets compromise with WARN_ON_ONCE() ;-)
> 
> I don't think WARN_ON is the right way to handle bad user input.
> It implies that when someone typos the result might end up in Arjan's 
> kerneloops.org database, which is not good.


Since I recommended an internal helper function, we could have:

int globmatch(const char *pat, const char *str)
{
	int ret;

	ret = globmatch_internal(pat, str, 0);
	if (ret < 0)
		WARN_ON();
	return ret;
}

int globmatch_user(const char *pat, const char *str)
{
	return globmatch_internal(pat, str, 0);
}


This would warn on if a kernel user caused the overflow, and also gives
a function that user space input could use, that would not warn on
overflow.

-- Steve


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