net: qcom/emac: Fix use after free bug in emac_remove due to race condition

mainline inclusion
from mainline-v6.3-rc4
commit 6b6bc5b8
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6ZWOL
CVE: CVE-2023-2483

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6b6bc5b8bd2d4ca9e1efa9ae0f98a0b0687ace75

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

In emac_probe, &adpt->work_thread is bound with
emac_work_thread. Then it will be started by timeout
handler emac_tx_timeout or a IRQ handler emac_isr.

If we remove the driver which will call emac_remove
  to make cleanup, there may be a unfinished work.

The possible sequence is as follows:

Fix it by finishing the work before cleanup in the emac_remove
and disable timeout response.

CPU0                  CPU1

                    |emac_work_thread
emac_remove         |
free_netdev         |
kfree(netdev);      |
                    |emac_reinit_locked
                    |emac_mac_down
                    |//use netdev
Fixes: b9b17deb ("net: emac: emac gigabit ethernet controller driver")
Signed-off-by: NZheng Wang <zyytlz.wz@163.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
(cherry picked from commit 6b6bc5b8)
Signed-off-by: NLiu Jian <liujian56@huawei.com>
Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
Reviewed-by: NWang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

drivers/net/ethernet/qualcomm/emac/emac.c

@@ -728,9 +728,15 @@ static int emac_remove(struct platform_device *pdev)
 	struct net_device *netdev = dev_get_drvdata(&pdev->dev);
 	struct emac_adapter *adpt = netdev_priv(netdev);
 
+	netif_carrier_off(netdev);
+	netif_tx_disable(netdev);
+
 	unregister_netdev(netdev);
 	netif_napi_del(&adpt->rx_q.napi);
 
+	free_irq(adpt->irq.irq, &adpt->irq);
+	cancel_work_sync(&adpt->work_thread);
+
 	emac_clks_teardown(adpt);
 
 	put_device(&adpt->phydev->mdio.dev);