From: Duoming Zhou <duoming@zju.edu.cn>
Date: Sat, 15 Apr 2023 16:12:27 +0800
Subject: cxgb4: fix use after free bugs caused by circular dependency problem
Patch-mainline: v6.3
Git-commit: e50b9b9e8610d47b7c22529443e45a16b1ea3a15
References: bsc#1213970 CVE-2023-4133
The flower_stats_timer can schedule flower_stats_work and
flower_stats_work can also arm the flower_stats_timer. The
process is shown below:
----------- timer schedules work ------------
ch_flower_stats_cb() //timer handler
schedule_work(&adap->flower_stats_work);
----------- work arms timer ------------
ch_flower_stats_handler() //workqueue callback function
mod_timer(&adap->flower_stats_timer, ...);
When the cxgb4 device is detaching, the timer and workqueue
could still be rearmed. The process is shown below:
(cleanup routine) | (timer and workqueue routine)
remove_one() |
free_some_resources() | ch_flower_stats_cb() //timer
cxgb4_cleanup_tc_flower() | schedule_work()
del_timer_sync() |
| ch_flower_stats_handler() //workqueue
| mod_timer()
cancel_work_sync() |
kfree(adapter) //FREE | ch_flower_stats_cb() //timer
| adap->flower_stats_work //USE
This patch changes del_timer_sync() to timer_shutdown_sync(),
which could prevent rearming of the timer from the workqueue.
Fixes: e0f911c81e93 ("cxgb4: fetch stats for offloaded tc flower flows")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20230415081227.7463-1-duoming@zju.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
@@ -882,7 +882,7 @@ void cxgb4_cleanup_tc_flower(struct adap
return;
if (adap->flower_stats_timer.function)
- del_timer_sync(&adap->flower_stats_timer);
+ timer_shutdown_sync(&adap->flower_stats_timer);
cancel_work_sync(&adap->flower_stats_work);
rhashtable_destroy(&adap->flower_tbl);
adap->tc_flower_initialized = false;