From 3c724888d2b1e085cd45343dee5f233aec705439 Mon Sep 17 00:00:00 2001
From: Alan <gnomes@lxorguk.ukuu.org.uk>
Date: Mon, 15 Feb 2016 19:09:46 +0000
Subject: chipidea: error on overflow for port_test_write

The write value is 8bit, but currently writing a larger number (eg a doubled
digit) is not errored but instead gets cast and sets off an action probably
undesired.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c
index de5c509..6d23eed 100644
--- a/drivers/usb/chipidea/debug.c
+++ b/drivers/usb/chipidea/debug.c
@@ -100,6 +100,9 @@ static ssize_t ci_port_test_write(struct file *file, const char __user *ubuf,
 	if (sscanf(buf, "%u", &mode) != 1)
 		return -EINVAL;
 
+	if (mode > 255)
+		return -EBADRQC;
+
 	pm_runtime_get_sync(ci->dev);
 	spin_lock_irqsave(&ci->lock, flags);
 	ret = hw_port_test_set(ci, mode);
-- 
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