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Date: Tue, 10 May 2016 22:20:37 +0300
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Kalle Valo <kvalo@codeaurora.org>
Cc: Ondrej Zary <linux@rainbow-software.org>,
	Florian Westphal <fw@strlen.de>,
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Subject: [patch] airo: prevent potential underflow in airo_set_freq()
Message-ID: <20160510192037.GB30712@mwanda> (sfid-20160510_212235_800106_89C82B92)
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I'm not sure if this can underflow but Smatch complains.  It seems
harmless to add a check for negatives.

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

diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index 55456f7..ca3cd21 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -5794,7 +5794,7 @@ static int airo_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;