[1/9] serial: arc_uart: Fix out-of-bounds access through DT alias

Message ID 1519119624-1268-2-git-send-email-geert+renesas@glider.be
State New
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Series
  • serial: Fix out-of-bounds accesses through DT aliases
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Commit Message

Geert Uytterhoeven Feb. 20, 2018, 9:40 a.m.
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: 10640deb04b7949a ("serial: arc_uart: Fix out-of-bounds access through DT alias")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/tty/serial/arc_uart.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Geert Uytterhoeven Feb. 20, 2018, 10:50 a.m. | #1
On Tue, Feb 20, 2018 at 10:40 AM, Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> 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: 10640deb04b7949a ("serial: arc_uart: Fix out-of-bounds access through DT alias")

Fixes: ea28fd56fcde69af ("serial/arc-uart: switch to devicetree based probing")

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Patch

diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 2599f9ecccfe7769..1cb827a6b836d0dd 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -593,6 +593,11 @@  static int arc_serial_probe(struct platform_device *pdev)
 	if (dev_id < 0)
 		dev_id = 0;
 
+	if (dev_id >= CONFIG_SERIAL_ARC_NR_PORTS) {
+		dev_err(&pdev->dev, "serial%d out of range\n", dev_id);
+		return -EINVAL;
+	}
+
 	uart = &arc_uart_ports[dev_id];
 	port = &uart->port;