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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pan Bian <bianpan2016@163.com>,
        Jakub Kicinski <kubakici@wp.pl>,
        Kalle Valo <kvalo@codeaurora.org>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 47/97] mt7601u: check return value of alloc_skb
Date:   Fri, 23 Mar 2018 10:54:34 +0100
Message-Id: <20180323094200.258964491@linuxfoundation.org>
In-Reply-To: <20180323094157.535925724@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pan Bian <bianpan2016@163.com>


[ Upstream commit 5fb01e91daf84ad1e50edfcf63116ecbe31e7ba7 ]

Function alloc_skb() will return a NULL pointer if there is no enough
memory. However, in function mt7601u_mcu_msg_alloc(), its return value
is not validated before it is used. This patch fixes it.

Signed-off-by: Pan Bian <bianpan2016@163.com>
Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireless/mediatek/mt7601u/mcu.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/net/wireless/mediatek/mt7601u/mcu.c
+++ b/drivers/net/wireless/mediatek/mt7601u/mcu.c
@@ -66,8 +66,10 @@ mt7601u_mcu_msg_alloc(struct mt7601u_dev
 	WARN_ON(len % 4); /* if length is not divisible by 4 we need to pad */
 
 	skb = alloc_skb(len + MT_DMA_HDR_LEN + 4, GFP_KERNEL);
-	skb_reserve(skb, MT_DMA_HDR_LEN);
-	memcpy(skb_put(skb, len), data, len);
+	if (skb) {
+		skb_reserve(skb, MT_DMA_HDR_LEN);
+		memcpy(skb_put(skb, len), data, len);
+	}
 
 	return skb;
 }
@@ -170,6 +172,8 @@ static int mt7601u_mcu_function_select(s
 	};
 
 	skb = mt7601u_mcu_msg_alloc(dev, &msg, sizeof(msg));
+	if (!skb)
+		return -ENOMEM;
 	return mt7601u_mcu_msg_send(dev, skb, CMD_FUN_SET_OP, func == 5);
 }
 
@@ -205,6 +209,8 @@ mt7601u_mcu_calibrate(struct mt7601u_dev
 	};
 
 	skb = mt7601u_mcu_msg_alloc(dev, &msg, sizeof(msg));
+	if (!skb)
+		return -ENOMEM;
 	return mt7601u_mcu_msg_send(dev, skb, CMD_CALIBRATION_OP, true);
 }