linux-kernel - [PATCH 3.10 083/268] tick/broadcast: Prevent NULL pointer dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 19 Jun 2017 20:29:42 +0200
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Mark Rutland <mark.rutland@....com>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Richard Cochran <rcochran@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Sebastian Frias <sf84@...oste.net>,
        Thibaud Cornic <thibaud_cornic@...madesigns.com>,
        Robin Murphy <robin.murphy@....com>,
        Jiri Slaby <jslaby@...e.cz>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 083/268] tick/broadcast: Prevent NULL pointer dereference

From: Thomas Gleixner <tglx@...utronix.de>

commit c1a9eeb938b5433947e5ea22f89baff3182e7075 upstream.

When a disfunctional timer, e.g. dummy timer, is installed, the tick core
tries to setup the broadcast timer.

If no broadcast device is installed, the kernel crashes with a NULL pointer
dereference in tick_broadcast_setup_oneshot() because the function has no
sanity check.

Reported-by: Mason <slash.tmp@...e.fr>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Anna-Maria Gleixner <anna-maria@...utronix.de>
Cc: Richard Cochran <rcochran@...utronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Cc: Sebastian Frias <sf84@...oste.net>
Cc: Thibaud Cornic <thibaud_cornic@...madesigns.com>
Cc: Robin Murphy <robin.murphy@....com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: Willy Tarreau <w@....eu>
---
 kernel/time/tick-broadcast.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 19ee339..6f27814 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -775,6 +775,9 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
 	int cpu = smp_processor_id();
 
+	if (!bc)
+		return;
+
 	/* Set it up only once ! */
 	if (bc->event_handler != tick_handle_oneshot_broadcast) {
 		int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
-- 
2.8.0.rc2.1.gbe9624a