From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35888 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732883AbeJBUTS (ORCPT ); Tue, 2 Oct 2018 16:19:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Team OWL337 , Thomas Gleixner , John Stultz , Sasha Levin Subject: [PATCH 4.9 27/94] alarmtimer: Prevent overflow for relative nanosleep Date: Tue, 2 Oct 2018 06:24:41 -0700 Message-Id: <20181002132502.389394923@linuxfoundation.org> In-Reply-To: <20181002132500.494838053@linuxfoundation.org> References: <20181002132500.494838053@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner [ Upstream commit 5f936e19cc0ef97dbe3a56e9498922ad5ba1edef ] 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 Signed-off-by: Thomas Gleixner Cc: John Stultz Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1807020926360.1595@nanos.tec.linutronix.de Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/time/alarmtimer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -786,7 +786,8 @@ static int alarm_timer_nsleep(const cloc /* 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); } if (alarmtimer_do_nsleep(&alarm, exp))