51 lines
1.9 KiB
Diff
51 lines
1.9 KiB
Diff
From 5f936e19cc0ef97dbe3a56e9498922ad5ba1edef Mon Sep 17 00:00:00 2001
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Mon, 2 Jul 2018 09:34:29 +0200
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Subject: alarmtimer: Prevent overflow for relative nanosleep
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Air Icy reported:
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UBSAN: Undefined behaviour in kernel/time/alarmtimer.c:811:7
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signed integer overflow:
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1529859276030040771 + 9223372036854775807 cannot be represented in type 'long long int'
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Call Trace:
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alarm_timer_nsleep+0x44c/0x510 kernel/time/alarmtimer.c:811
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__do_sys_clock_nanosleep kernel/time/posix-timers.c:1235 [inline]
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__se_sys_clock_nanosleep kernel/time/posix-timers.c:1213 [inline]
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__x64_sys_clock_nanosleep+0x326/0x4e0 kernel/time/posix-timers.c:1213
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do_syscall_64+0xb8/0x3a0 arch/x86/entry/common.c:290
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alarm_timer_nsleep() uses ktime_add() to add the current time and the
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relative expiry value. ktime_add() has no sanity checks so the addition
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can overflow when the relative timeout is large enough.
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Use ktime_add_safe() which has the necessary sanity checks in place and
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limits the result to the valid range.
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Fixes: 9a7adcf5c6de ("timers: Posix interface for alarm-timers")
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Reported-by: Team OWL337 <icytxw@gmail.com>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: John Stultz <john.stultz@linaro.org>
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Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1807020926360.1595@nanos.tec.linutronix.de
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---
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kernel/time/alarmtimer.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
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index 78a3cc5..fa5de5e 100644
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--- a/kernel/time/alarmtimer.c
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+++ b/kernel/time/alarmtimer.c
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@@ -808,7 +808,8 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
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/* Convert (if necessary) to absolute time */
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if (flags != TIMER_ABSTIME) {
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ktime_t now = alarm_bases[type].gettime();
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- exp = ktime_add(now, exp);
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+
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+ exp = ktime_add_safe(now, exp);
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}
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ret = alarmtimer_do_nsleep(&alarm, exp, type);
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--
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cgit v1.1
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