Messages in this thread Patch in this message | | | Subject | [PATCH] hrtimer: prevent overrun DoS in hrtimer_forward() | From | Thomas Gleixner <> | Date | Wed, 14 Mar 2007 11:00:12 +0100 |
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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>
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ec4cb9f..5e7122d 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -644,6 +644,12 @@ 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; }
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