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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, George Kennedy <george.kennedy@oracle.com>,
        syzbot+4cd84f527bf4a10fc9c1@syzkaller.appspotmail.com,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.7 052/179] ax88172a: fix ax88172a_unbind() failures
Date:   Mon, 27 Jul 2020 16:03:47 +0200
Message-Id: <20200727134935.202883308@linuxfoundation.org>
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From: George Kennedy <george.kennedy@oracle.com>

[ Upstream commit c28d9a285668c799eeae2f7f93e929a6028a4d6d ]

If ax88172a_unbind() fails, make sure that the return code is
less than zero so that cleanup is done properly and avoid UAF.

Fixes: a9a51bd727d1 ("ax88172a: fix information leak on short answers")
Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Reported-by: syzbot+4cd84f527bf4a10fc9c1@syzkaller.appspotmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/ax88172a.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
index 4e514f5d7c6c7..fd3a04d98dc14 100644
--- a/drivers/net/usb/ax88172a.c
+++ b/drivers/net/usb/ax88172a.c
@@ -187,6 +187,7 @@ static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
 	ret = asix_read_cmd(dev, AX_CMD_READ_NODE_ID, 0, 0, ETH_ALEN, buf, 0);
 	if (ret < ETH_ALEN) {
 		netdev_err(dev->net, "Failed to read MAC address: %d\n", ret);
+		ret = -EIO;
 		goto free;
 	}
 	memcpy(dev->net->dev_addr, buf, ETH_ALEN);
-- 
2.25.1