serial: arc_uart: Fix out-of-bounds access through DT alias

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: ea28fd56fc ("serial/arc-uart: switch to devicetree based probing")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2018-02-23 14:38:29 +01:00 committed by Greg Kroah-Hartman
parent 42afa627c3
commit f9f5786987

View file

@ -593,6 +593,11 @@ 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;