| From: Geert Uytterhoeven <geert+renesas@glider.be> |
| Date: Fri, 23 Feb 2018 14:38:29 +0100 |
| Subject: serial: arc_uart: Fix out-of-bounds access through DT alias |
| |
| commit f9f5786987e81d166c60833edcb7d1836aa16944 upstream. |
| |
| 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| [bwh: Backported to 3.16: Put the check in arc_uart_init_one() and move |
| initialisation of the uart variable below it] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| --- a/drivers/tty/serial/arc_uart.c |
| +++ b/drivers/tty/serial/arc_uart.c |
| @@ -531,8 +531,14 @@ arc_uart_init_one(struct platform_device |
| { |
| struct resource *res, *res2; |
| unsigned long *plat_data; |
| - struct arc_uart_port *uart = &arc_uart_ports[dev_id]; |
| + struct arc_uart_port *uart; |
| |
| + 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]; |
| plat_data = dev_get_platdata(&pdev->dev); |
| if (!plat_data) |
| return -ENODEV; |