From 5c7a3a3d20a4e175304c0e23809e3d70be8fed8a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 12 Jun 2017 19:44:09 +0200 Subject: [PATCH] posix-timers: Zero out oldval itimerspec The recent posix timer rework moved the clearing of the itimerspec to the real syscall implementation, but forgot that the kclock->timer_get() is used by timer_settime() as well. That results in an uninitialized variable and bogus values returned to user space. Add the missing memset to timer_settime(). Fixes: eabdec043853 ("posix-timers: Zero settings value in common code") Reported-by: Andrei Vagin Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: John Stultz Cc: Cyrill Gorcunov Link: http://lkml.kernel.org/r/20170609201156.GB21491@outlook.office365.com --- kernel/time/posix-timers.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index b53a0b562516..88517dcfe0ca 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -828,6 +828,8 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags, if (!timespec64_valid(&new_spec64.it_interval) || !timespec64_valid(&new_spec64.it_value)) return -EINVAL; + if (rtn) + memset(rtn, 0, sizeof(*rtn)); retry: timr = lock_timer(timer_id, &flag); if (!timr)