From 65cb24de03f1c8e00a4fedf416b80a4e8f8a6ef2 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 1 Nov 2018 13:02:38 -0700 Subject: posix-timers: Sanitize overrun handling [ Upstream commit 78c9c4dfbf8c04883941445a195276bb4bb92c76 ] The posix timer overrun handling is broken because the forwarding functions can return a huge number of overruns which does not fit in an int. As a consequence timer_getoverrun(2) and siginfo::si_overrun can turn into random number generators. The k_clock::timer_forward() callbacks return a 64 bit value now. Make k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal accounting is correct. 3Remove the temporary (int) casts. Add a helper function which clamps the overrun value returned to user space via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value between 0 and INT_MAX. INT_MAX is an indicator for user space that the overrun value has been clamped. Reported-by: Team OWL337 Signed-off-by: Thomas Gleixner Acked-by: John Stultz Cc: Peter Zijlstra Cc: Michael Kerrisk Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de [florian: Make patch apply to v4.9.135] Signed-off-by: Florian Fainelli Reviewed-by: Thomas Gleixner Signed-off-by: Sasha Levin --- include/linux/posix-timers.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 62d44c176071..e4b8678183f5 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -65,8 +65,8 @@ struct k_itimer { spinlock_t it_lock; clockid_t it_clock; /* which timer type */ timer_t it_id; /* timer id */ - int it_overrun; /* overrun on pending signal */ - int it_overrun_last; /* overrun on last delivered signal */ + s64 it_overrun; /* overrun on pending signal */ + s64 it_overrun_last; /* overrun on last delivered signal */ int it_requeue_pending; /* waiting to requeue this timer */ #define REQUEUE_PENDING 1 int it_sigev_notify; /* notify word of sigevent struct */ -- cgit v1.2.3