[6/9] serial: samsung: Fix out-of-bounds access through DT alias

Message ID 1519119624-1268-7-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 s3c24xx_serial_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_SAMSUNG_UARTS), so this can even be triggered using a
legitimate DTB.

Fixes: 3ac337e76a1c637b ("serial: samsung: Fix out-of-bounds access through DT alias")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/tty/serial/samsung.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Geert Uytterhoeven Feb. 20, 2018, 10:52 a.m. | #1
On Tue, Feb 20, 2018 at 10:40 AM, Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
> The s3c24xx_serial_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_SAMSUNG_UARTS), so this can even be triggered using a
> legitimate DTB.
>
> Fixes: 3ac337e76a1c637b ("serial: samsung: Fix out-of-bounds access through DT alias")

Fixes: 13a9f6c64fdc55eb ("serial: samsung: Consider DT alias when probing po
rts")

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/samsung.c b/drivers/tty/serial/samsung.c
index f9fecc5ed0cee826..9ea42197ceefabba 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1818,6 +1818,10 @@  static int s3c24xx_serial_probe(struct platform_device *pdev)
 
 	dbg("s3c24xx_serial_probe(%p) %d\n", pdev, index);
 
+	if (index >= CONFIG_SERIAL_SAMSUNG_UARTS) {
+		dev_err(&pdev->dev, "serial%d out of range\n", index);
+		return -EINVAL;
+	}
 	ourport = &s3c24xx_serial_ports[index];
 
 	ourport->drv_data = s3c24xx_get_driver_data(pdev);