From 5515e9a6273b8c02034466bcbd717ac9f53dab99 Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue, 16 Jul 2019 16:30:09 -0700
Subject: [PATCH] drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
Git-commit: 5515e9a6273b8c02034466bcbd717ac9f53dab99
Patch-mainline: v5.3-rc1
References: bsc#1051510

The PPS assert/clear offset corrections are set by the PPS_SETPARAMS
ioctl in the pps_ktime structs, which also contain flags.  The flags are
not initialized by applications (using the timepps.h header) and they
are not used by the kernel for anything except returning them back in
the PPS_GETPARAMS ioctl.

Set the flags to zero to make it clear they are unused and avoid leaking
uninitialized data of the PPS_SETPARAMS caller to other applications
that have a read access to the PPS device.

Link: http://lkml.kernel.org/r/20190702092251.24303-1-mlichvar@redhat.com
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Cc: Greg KH <greg@kroah.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/pps/pps.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 3a546ec10d90..22a65ad4e46e 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -152,6 +152,14 @@ static long pps_cdev_ioctl(struct file *file,
 			pps->params.mode |= PPS_CANWAIT;
 		pps->params.api_version = PPS_API_VERS;
 
+		/*
+		 * Clear unused fields of pps_kparams to avoid leaking
+		 * uninitialized data of the PPS_SETPARAMS caller via
+		 * PPS_GETPARAMS
+		 */
+		pps->params.assert_off_tu.flags = 0;
+		pps->params.clear_off_tu.flags = 0;
+
 		spin_unlock_irq(&pps->lock);
 
 		break;
-- 
2.16.4