From: Zheng Wang <zyytlz.wz@163.com>

Date: Fri, 17 Mar 2023 00:15:26 +0800

Subject: xirc2ps_cs: Fix use after free bug in xirc2ps_detach

Patch-mainline: v6.3-rc4

Git-commit: e8d20c3ded59a092532513c9bd030d1ea66f5f44

References: bsc#1209871 CVE-2023-1670

In xirc2ps_probe, the local->tx_timeout_task was bounded

with xirc2ps_tx_timeout_task. When timeout occurs,

it will call xirc_tx_timeout->schedule_work to start the

work.

When we call xirc2ps_detach to remove the driver, there

may be a sequence as follows:

Stop responding to timeout tasks and complete scheduled

tasks before cleanup in xirc2ps_detach, which will fix

the problem.

CPU0                  CPU1

                    |xirc2ps_tx_timeout_task

xirc2ps_detach      |

  free_netdev       |

    kfree(dev);     |

                    |

                    | do_reset

                    |   //use dev

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

Signed-off-by: Zheng Wang <zyytlz.wz@163.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Acked-by: Lee, Chun-Yi <jlee@suse.com>

---

 drivers/net/ethernet/xircom/xirc2ps_cs.c |    5 +++++

 1 file changed, 5 insertions(+)

--- a/drivers/net/ethernet/xircom/xirc2ps_cs.c

+++ b/drivers/net/ethernet/xircom/xirc2ps_cs.c

@@ -503,6 +503,11 @@ static void

 xirc2ps_detach(struct pcmcia_device *link)

 {

     struct net_device *dev = link->priv;

+    struct local_info *local = netdev_priv(dev);

+

+    netif_carrier_off(dev);

+    netif_tx_disable(dev);

+    cancel_work_sync(&local->tx_timeout_task);

     dev_dbg(&link->dev, "detach\n");