releases/4.9.103/serial-fsl_lpuart-fix-out-of-bounds-access-through-dt-alias.patch

From foo@baz Thu May 24 11:23:00 CEST 2018
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri, 23 Feb 2018 14:38:30 +0100
Subject: serial: fsl_lpuart: Fix out-of-bounds access through DT alias

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

[ Upstream commit ffab87fdecc655cc676f8be8dd1a2c5e22bd6d47 ]

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+renesas@glider.be>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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
@@ -1902,6 +1902,10 @@ 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;
 	sport->lpuart32 = of_device_is_compatible(np, "fsl,ls1021a-lpuart");