linux-kernel - [patch] atmel: potential underflow in atmel_set

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Date:	Tue, 10 May 2016 22:21:17 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Simon Kelley <simon@...kelleys.org.uk>
Cc:	Kalle Valo <kvalo@...eaurora.org>, linux-wireless@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] atmel: potential underflow in atmel_set_freq()

Smatch complains that we cap the upper bound of "fwrq->m" but not the
lower bound.  I don't know if it can actually happen but it's simple
enough to check for negatives.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/drivers/net/wireless/atmel/atmel.c b/drivers/net/wireless/atmel/atmel.c
index 8f8f37f..bf2e9a0 100644
--- a/drivers/net/wireless/atmel/atmel.c
+++ b/drivers/net/wireless/atmel/atmel.c
@@ -2275,7 +2275,7 @@ static int atmel_set_freq(struct net_device *dev,
 		fwrq->m = ieee80211_frequency_to_channel(f);
 	}
 	/* Setting by channel number */
-	if ((fwrq->m > 1000) || (fwrq->e > 0))
+	if (fwrq->m < 0 || fwrq->m > 1000 || fwrq->e > 0)
 		rc = -EOPNOTSUPP;
 	else {
 		int channel = fwrq->m;