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| author | Thomas Gleixner <tglx@linutronix.de> | 2017-06-20 17:37:35 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-06-20 21:33:56 +0200 |
| commit | 35eb7258c009dc478338e674a5a84d25d0929c56 (patch) | |
| tree | 7fae943ef2569bf8db0a2e76b60c6027698f3760 /kernel/time/itimer.c | |
| parent | d15bc69affc57d7985a01745ca28eafa0772325b (diff) | |
| download | linux-35eb7258c009dc478338e674a5a84d25d0929c56.tar.bz2 | |
itimer: Make timeval to nsec conversion range limited
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 <qiuxishi@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170620154113.505981643@linutronix.de
Diffstat (limited to 'kernel/time/itimer.c')
| -rw-r--r-- | kernel/time/itimer.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index 9dd7ff5e445a..2ef98a02376a 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -152,8 +152,12 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, 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); |