Re: [patch 2/2] Validate and sanitze itimer timeval from userspace

From: Andrew Morton
Date: Mon Mar 20 2006 - 01:13:46 EST


Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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;

?
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