summaryrefslogtreecommitdiff
path: root/kernel/time/posix-cpu-timers.c
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2018-06-26 15:21:32 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-07-02 11:33:25 +0200
commit78c9c4dfbf8c04883941445a195276bb4bb92c76 (patch)
treeca626839d808acf6f664cc27a322c418bb68d31e /kernel/time/posix-cpu-timers.c
parent6fec64e1c92d5c715c6d0f50786daa7708266bde (diff)
posix-timers: Sanitize overrun handling
The posix timer overrun handling is broken because the forwarding functions can return a huge number of overruns which does not fit in an int. As a consequence timer_getoverrun(2) and siginfo::si_overrun can turn into random number generators. The k_clock::timer_forward() callbacks return a 64 bit value now. Make k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal accounting is correct. 3Remove the temporary (int) casts. Add a helper function which clamps the overrun value returned to user space via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value between 0 and INT_MAX. INT_MAX is an indicator for user space that the overrun value has been clamped. Reported-by: Team OWL337 <icytxw@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de
Diffstat (limited to 'kernel/time/posix-cpu-timers.c')
-rw-r--r--kernel/time/posix-cpu-timers.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 5a6251ac6f7a..562cc3891b57 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -85,7 +85,7 @@ static void bump_cpu_timer(struct k_itimer *timer, u64 now)
continue;
timer->it.cpu.expires += incr;
- timer->it_overrun += 1 << i;
+ timer->it_overrun += 1LL << i;
delta -= incr;
}
}