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authorThomas Gleixner <tglx@linutronix.de>2007-02-16 01:28:12 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-16 08:13:59 -0800
commit8bfd9a7a229b5f3d3eda5d7d45c2eebec5b4ba16 (patch)
tree01c910a659f387b921493cab9bd4decd8fa66a4e /kernel/itimer.c
parent54cdfdb47f73b5af3d1ebb0f1e383efbe70fde9e (diff)
[PATCH] hrtimers: prevent possible itimer DoS
Fix potential setitimer DoS with high-res timers by pushing itimer rearm processing to process context. [Fixes from: Ingo Molnar <mingo@elte.hu>] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/itimer.c')
-rw-r--r--kernel/itimer.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/kernel/itimer.c b/kernel/itimer.c
index 4fc6c0caf5d..307c6a632ef 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -135,11 +135,6 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer)
send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk);
- if (sig->it_real_incr.tv64 != 0) {
- hrtimer_forward(timer, hrtimer_cb_get_time(timer),
- sig->it_real_incr);
- return HRTIMER_RESTART;
- }
return HRTIMER_NORESTART;
}
@@ -231,11 +226,14 @@ again:
spin_unlock_irq(&tsk->sighand->siglock);
goto again;
}
- tsk->signal->it_real_incr =
- timeval_to_ktime(value->it_interval);
expires = timeval_to_ktime(value->it_value);
- if (expires.tv64 != 0)
+ if (expires.tv64 != 0) {
+ tsk->signal->it_real_incr =
+ timeval_to_ktime(value->it_interval);
hrtimer_start(timer, expires, HRTIMER_MODE_REL);
+ } else
+ tsk->signal->it_real_incr.tv64 = 0;
+
spin_unlock_irq(&tsk->sighand->siglock);
break;
case ITIMER_VIRTUAL: