From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752123AbdFTToF (ORCPT ); Tue, 20 Jun 2017 15:44:05 -0400 Received: from terminus.zytor.com ([65.50.211.136]:47797 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751029AbdFTToD (ORCPT ); Tue, 20 Jun 2017 15:44:03 -0400 Date: Tue, 20 Jun 2017 12:39:27 -0700 From: tip-bot for Thomas Gleixner Message-ID: Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, peterz@infradead.org, qiuxishi@huawei.com, tglx@linutronix.de, john.stultz@linaro.org Reply-To: peterz@infradead.org, hpa@zytor.com, mingo@kernel.org, linux-kernel@vger.kernel.org, john.stultz@linaro.org, tglx@linutronix.de, qiuxishi@huawei.com In-Reply-To: <20170620154113.505981643@linutronix.de> References: <20170620154113.505981643@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] itimer: Make timeval to nsec conversion range limited Git-Commit-ID: 35eb7258c009dc478338e674a5a84d25d0929c56 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 35eb7258c009dc478338e674a5a84d25d0929c56 Gitweb: http://git.kernel.org/tip/35eb7258c009dc478338e674a5a84d25d0929c56 Author: Thomas Gleixner AuthorDate: Tue, 20 Jun 2017 17:37:35 +0200 Committer: Thomas Gleixner CommitDate: Tue, 20 Jun 2017 21:33:56 +0200 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 Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz Link: http://lkml.kernel.org/r/20170620154113.505981643@linutronix.de --- kernel/time/itimer.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index 9dd7ff5..2ef98a0 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);