From 1c447ea137037fb3dae452efc28f607020df76d0 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri, 23 Feb 2018 14:38:29 +0100
Subject: [PATCH] serial: arc_uart: Fix out-of-bounds access through DT alias
[ Upstream commit f9f5786987e81d166c60833edcb7d1836aa16944 ]
The arc_uart_ports[] array is indexed using a value derived from the
"serialN" alias in DT, which may lead to an out-of-bounds access.
Fix this by adding a range check.
Note that the array size is defined by a Kconfig symbol
(CONFIG_SERIAL_ARC_NR_PORTS), so this can even be triggered using a
legitimate DTB.
Fixes: ea28fd56fcde69af ("serial/arc-uart: switch to devicetree based probing")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/arc_uart.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 77fe306690c4..71e37abb6bcb 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -596,6 +596,11 @@ static int arc_serial_probe(struct platform_device *pdev)
if (dev_id < 0)
dev_id = 0;
+ if (dev_id >= ARRAY_SIZE(arc_uart_ports)) {
+ dev_err(&pdev->dev, "serial%d out of range\n", dev_id);
+ return -EINVAL;
+ }
+
uart = &arc_uart_ports[dev_id];
port = &uart->port;