From: Duoming Zhou <duoming@zju.edu.cn>
To: linux-hams@vger.kernel.org
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
ralf@linux-mips.org, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com,
Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH net v2] net: rose: fix UAF bug caused by rose_t0timer_expiry
Date: Tue, 5 Jul 2022 20:56:10 +0800 [thread overview]
Message-ID: <20220705125610.77971-1-duoming@zju.edu.cn> (raw)
There are UAF bugs caused by rose_t0timer_expiry(). The
root cause is that del_timer() could not stop the timer
handler that is running and there is no synchronization.
One of the race conditions is shown below:
(thread 1) | (thread 2)
| rose_device_event
| rose_rt_device_down
| rose_remove_neigh
rose_t0timer_expiry | rose_stop_t0timer(rose_neigh)
... | del_timer(&neigh->t0timer)
| kfree(rose_neigh) //[1]FREE
neigh->dce_mode //[2]USE |
The rose_neigh is deallocated in position [1] and use in
position [2].
The crash trace triggered by POC is like below:
BUG: KASAN: use-after-free in expire_timers+0x144/0x320
Write of size 8 at addr ffff888009b19658 by task swapper/0/0
...
Call Trace:
<IRQ>
dump_stack_lvl+0xbf/0xee
print_address_description+0x7b/0x440
print_report+0x101/0x230
? expire_timers+0x144/0x320
kasan_report+0xed/0x120
? expire_timers+0x144/0x320
expire_timers+0x144/0x320
__run_timers+0x3ff/0x4d0
run_timer_softirq+0x41/0x80
__do_softirq+0x233/0x544
...
This patch changes rose_stop_ftimer() and rose_stop_t0timer()
in rose_remove_neigh() to del_timer_sync() in order that the
timer handler could be finished before the resources such as
rose_neigh and so on are deallocated. As a result, the UAF
bugs could be mitigated.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
Changes in v2:
- v2: Use del_timer_sync to stop timer in rose_remove_neigh.
net/rose/rose_route.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c
index fee6409c2bb..eb0b8197ac8 100644
--- a/net/rose/rose_route.c
+++ b/net/rose/rose_route.c
@@ -227,8 +227,8 @@ static void rose_remove_neigh(struct rose_neigh *rose_neigh)
{
struct rose_neigh *s;
- rose_stop_ftimer(rose_neigh);
- rose_stop_t0timer(rose_neigh);
+ del_timer_sync(&rose_neigh->ftimer);
+ del_timer_sync(&rose_neigh->t0timer);
skb_queue_purge(&rose_neigh->queue);
--
2.17.1
next reply other threads:[~2022-07-05 12:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 12:56 Duoming Zhou [this message]
2022-07-07 2:02 ` [PATCH net v2] net: rose: fix UAF bug caused by rose_t0timer_expiry Jakub Kicinski
2022-07-07 2:23 ` duoming
2022-07-07 3:00 ` patchwork-bot+netdevbpf
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