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Date: Sun, 19 Mar 2006 22:13:22 -0800
From: Andrew Morton <akpm@osdl.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, trini@kernel.crashing.org
Subject: Re: [patch 2/2] Validate and sanitze itimer timeval from userspace
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Thomas Gleixner <tglx@linutronix.de> wrote:
>
> +static void fixup_timeval(struct timeval *tv, int interval)
>  +{
> ...
>  +	tmp = (unsigned long) tv->tv_usec;
>  +	if (tmp >= USEC_PER_SEC)
>  +		tv->tv_usec = USEC_PER_SEC - 1;
>  +
>  +	tmp = (unsigned long) tv->tv_sec;
>  +	if (tmp > (LONG_MAX >> 1))
>  +		tv->tv_sec = (LONG_MAX >> 1);
>  +}

Earlier kernels normalised the time, but this code truncates it.

For compatibility, shouldn't we be doing

	tv->tv_sec += tv->tv_usec / USEC_PER_SEC;

?