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From:   Pan Bian <bianpan2016@163.com>
To:     Herton Ronaldo Krzesinski <herton@canonical.com>,
        Hin-Tak Leung <htl10@users.sourceforge.net>,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>
Cc:     linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Pan Bian <bianpan2016@163.com>
Subject: [PATCH] rtl818x: fix potential use after free
Date:   Thu, 29 Nov 2018 18:48:10 +0800
Message-Id: <1543488490-101743-1-git-send-email-bianpan2016@163.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

entry is released via usb_put_urb just after calling usb_submit_urb.
However, entry is used if the submission fails, resulting in a use after
free bug. The patch fixes this.

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
index cec3778..1a2ea8b 100644
--- a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
+++ b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
@@ -444,12 +444,13 @@ static int rtl8187_init_urbs(struct ieee80211_hw *dev)
 		skb_queue_tail(&priv->rx_queue, skb);
 		usb_anchor_urb(entry, &priv->anchored);
 		ret = usb_submit_urb(entry, GFP_KERNEL);
-		usb_put_urb(entry);
 		if (ret) {
 			skb_unlink(skb, &priv->rx_queue);
 			usb_unanchor_urb(entry);
+			usb_put_urb(entry);
 			goto err;
 		}
+		usb_put_urb(entry);
 	}
 	return ret;
 
-- 
2.7.4