The expiry time of a itimer is supplied through sys_setitimer() via a
struct timeval. The timeval is validated for correctness.
In the actual set timer implementation the timeval is converted to a
scalar nanoseconds value. If the tv_sec part of the time spec is large
enough the conversion to nanoseconds (sec * NSEC_PER_SEC) overflows 64bit.
Mitigate that by using the timeval_to_ktime() conversion function, which
checks the tv_sec part for a potential mult overflow and clamps the result
to KTIME_MAX, which is about 292 years.
Reported-by: Xishi Qiu <qiuxi...@huawei.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
kernel/time/itimer.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
kernel/time/itimer.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -138,8 +138,12 @@ static void set_cpu_itimer(struct task_s
u64 oval, nval, ointerval, ninterval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
- nval = timeval_to_ns(&value->it_value);
- ninterval = timeval_to_ns(&value->it_interval);
+ /*
+ * Use the to_ktime conversion because that clamps the maximum
+ * value to KTIME_MAX and avoid multiplication overflows.
+ */
+ nval = ktime_to_ns(timeval_to_ktime(value->it_value));
+ ninterval = ktime_to_ns(timeval_to_ktime(value->it_interval));
spin_lock_irq(&tsk->sighand->siglock);
