2023-03-16 15:19:17

by Zheng Wang

[permalink] [raw]
Subject: [PATCH v4] xirc2ps_cs: Fix use after free bug in xirc2ps_detach

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 <[email protected]>
---
v4:
- fix indentation error again

v3:
- fix indentation error suggested by Jakub Kicinski

v2:
- fix indentation error suggested by Simon Horman,
and stop the timeout tasks suggested by Yunsheng Lin
---
drivers/net/ethernet/xircom/xirc2ps_cs.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/xircom/xirc2ps_cs.c b/drivers/net/ethernet/xircom/xirc2ps_cs.c
index 894e92ef415b..e04b3f7f2179 100644
--- a/drivers/net/ethernet/xircom/xirc2ps_cs.c
+++ b/drivers/net/ethernet/xircom/xirc2ps_cs.c
@@ -503,7 +503,12 @@ 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");

unregister_netdev(dev);
--
2.25.1