serial: fsl_lpuart: Fix out-of-bounds access through DT alias

[ 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>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 76103f2..937f5e1 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1902,6 +1902,10 @@ static int lpuart_probe(struct platform_device *pdev)
                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");