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From:   Zheng Wang <zyytlz.wz@163.com>
To:     s.shtylyov@omp.ru
Cc:     lee@kernel.org, linyunsheng@huawei.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        richardcochran@gmail.com, p.zabel@pengutronix.de,
        geert+renesas@glider.be, magnus.damm@gmail.com,
        yoshihiro.shimoda.uh@renesas.com, biju.das.jz@bp.renesas.com,
        wsa+renesas@sang-engineering.com, netdev@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
        hackerzheng666@gmail.com, 1395428693sheep@gmail.com,
        alex000young@gmail.com, Zheng Wang <zyytlz.wz@163.com>
Subject: [PATCH v4] net: ravb: Fix possible UAF bug in ravb_remove
Date:   Tue, 25 Jul 2023 11:00:26 +0800
Message-Id: <20230725030026.1664873-1-zyytlz.wz@163.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In ravb_probe, priv->work was bound with ravb_tx_timeout_work.
If timeout occurs, it will start the work. And if we call
ravb_remove without finishing the work, there may be a
use-after-free bug on ndev.

Fix it by finishing the job before cleanup in ravb_remove.

Note that this bug is found by static analysis, it might be
false positive.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
---
v4:
- add information about the bug was found suggested by Yunsheng Lin
v3:
- fix typo in commit message
v2:
- stop dev_watchdog so that handle no more timeout work suggested by Yunsheng Lin,
add an empty line to make code clear suggested by Sergey Shtylyov
---
 drivers/net/ethernet/renesas/ravb_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 4d6b3b7d6abb..ce2da5101e51 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2885,6 +2885,9 @@ static int ravb_remove(struct platform_device *pdev)
 	struct ravb_private *priv = netdev_priv(ndev);
 	const struct ravb_hw_info *info = priv->info;
 
+	netif_carrier_off(ndev);
+	netif_tx_disable(ndev);
+	cancel_work_sync(&priv->work);
 	/* Stop PTP Clock driver */
 	if (info->ccc_gac)
 		ravb_ptp_stop(ndev);
-- 
2.25.1