[PATCH 3.16 019/366] serial: fsl_lpuart: Fix out-of-bounds access through DT alias

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert+rene...@glider.be>

commit ffab87fdecc655cc676f8be8dd1a2c5e22bd6d47 upstream.

The lpuart_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.

Fixes: c9e2e946fb0ba5d2 ("tty: serial: add Freescale lpuart driver support")
Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 drivers/tty/serial/fsl_lpuart.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1170,6 +1170,10 @@ static int lpuart_probe(struct platform_
                dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
                return ret;
        }
+       if (ret >= ARRAY_SIZE(lpuart_ports)) {
+               dev_err(&pdev->dev, "serial%d out of range\n", ret);
+               return -EINVAL;
+       }
        sport->port.line = ret;
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);