Messages in this thread Patch in this message | | | Date | Mon, 19 Mar 2007 14:39:20 -0700 | From | Greg KH <> | Subject | [patch 14/31] hrtimer: prevent overrun DoS in hrtimer_forward() |
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-stable review patch. If anyone has any objections, please let us know.
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From: Thomas Gleixner <tglx@linutronix.de>
hrtimer_forward() does not check for the possible overflow of timer->expires. This can happen on 64 bit machines with large interval values and results currently in an endless loop in the softirq because the expiry value becomes negative and therefor the timer is expired all the time.
Check for this condition and set the expiry value to the max. expiry time in the future. The fix should be applied to stable kernel series as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/hrtimer.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -332,6 +332,12 @@ hrtimer_forward(struct hrtimer *timer, k orun++; } timer->expires = ktime_add(timer->expires, interval); + /* + * Make sure, that the result did not wrap with a very large + * interval. + */ + if (timer->expires.tv64 < 0) + timer->expires = ktime_set(KTIME_SEC_MAX, 0); return orun; } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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