linux-kernel - [patch 0/2] posix-timers: Sanitize posix timer overrun handling

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Message-ID: <20180626132130.345959379@linutronix.de>
Date:   Tue, 26 Jun 2018 15:21:30 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     John Stultz <john.stultz@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Michael Kerrisk <mtk.manpages@...il.com>,
        air icy <icytxw@...il.com>
Subject: [patch 0/2] posix-timers: Sanitize posix timer overrun handling

Icy reported an UBSAN splat in the posix timer code, which is caused by the
way the overrun accounting works. Depending on interval and expiry time the
overrun can be larger than INT_MAX, but the accounting is int based which
basically makes the accounting values, which are visible to user space via
timer_getoverrrun(2) and siginfo::si_overrun, random.

The following series addresses this by converting the internal accounting
to 64bit and clamping the user space visible values to INT_MAX.

Thanks,

	tglx

8<-------------------
 b/include/linux/posix-timers.h |    4 ++--
 kernel/time/alarmtimer.c       |    4 ++--
 kernel/time/posix-cpu-timers.c |    2 +-
 kernel/time/posix-timers.c     |   33 +++++++++++++++++++++------------
 kernel/time/posix-timers.h     |    2 +-
 5 files changed, 27 insertions(+), 18 deletions(-)