summaryrefslogtreecommitdiff
path: root/kernel/time/alarmtimer.c
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2018-07-02 09:34:29 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-07-02 11:33:26 +0200
commit5f936e19cc0ef97dbe3a56e9498922ad5ba1edef (patch)
treee090b44b1437642d9702c599576c0303c268ed8c /kernel/time/alarmtimer.c
parent78c9c4dfbf8c04883941445a195276bb4bb92c76 (diff)
alarmtimer: Prevent overflow for relative nanosleep
Air Icy reported: UBSAN: Undefined behaviour in kernel/time/alarmtimer.c:811:7 signed integer overflow: 1529859276030040771 + 9223372036854775807 cannot be represented in type 'long long int' Call Trace: alarm_timer_nsleep+0x44c/0x510 kernel/time/alarmtimer.c:811 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1235 [inline] __se_sys_clock_nanosleep kernel/time/posix-timers.c:1213 [inline] __x64_sys_clock_nanosleep+0x326/0x4e0 kernel/time/posix-timers.c:1213 do_syscall_64+0xb8/0x3a0 arch/x86/entry/common.c:290 alarm_timer_nsleep() uses ktime_add() to add the current time and the relative expiry value. ktime_add() has no sanity checks so the addition can overflow when the relative timeout is large enough. Use ktime_add_safe() which has the necessary sanity checks in place and limits the result to the valid range. Fixes: 9a7adcf5c6de ("timers: Posix interface for alarm-timers") Reported-by: Team OWL337 <icytxw@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1807020926360.1595@nanos.tec.linutronix.de
Diffstat (limited to 'kernel/time/alarmtimer.c')
-rw-r--r--kernel/time/alarmtimer.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 78a3cc555823..fa5de5e8de61 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -808,7 +808,8 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
/* Convert (if necessary) to absolute time */
if (flags != TIMER_ABSTIME) {
ktime_t now = alarm_bases[type].gettime();
- exp = ktime_add(now, exp);
+
+ exp = ktime_add_safe(now, exp);
}
ret = alarmtimer_do_nsleep(&alarm, exp, type);