From: Duoming Zhou <duoming@zju.edu.cn>
To: linux-hams@vger.kernel.org
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
pabeni@redhat.com, kuba@kernel.org, edumazet@google.com,
davem@davemloft.net, ralf@linux-mips.org,
Duoming Zhou <duoming@zju.edu.cn>
Subject: [PATCH net] net: rose: fix UAF bug caused by rose_t0timer_expiry
Date: Thu, 30 Jun 2022 22:38:42 +0800 [thread overview]
Message-ID: <20220630143842.24906-1-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 del_timer() in rose_stop_t0timer() and
rose_stop_ftimer() 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>
---
net/rose/rose_link.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/rose/rose_link.c b/net/rose/rose_link.c
index 8b96a56d3a4..9734d1264de 100644
--- a/net/rose/rose_link.c
+++ b/net/rose/rose_link.c
@@ -54,12 +54,12 @@ static void rose_start_t0timer(struct rose_neigh *neigh)
void rose_stop_ftimer(struct rose_neigh *neigh)
{
- del_timer(&neigh->ftimer);
+ del_timer_sync(&neigh->ftimer);
}
void rose_stop_t0timer(struct rose_neigh *neigh)
{
- del_timer(&neigh->t0timer);
+ del_timer_sync(&neigh->t0timer);
}
int rose_ftimer_running(struct rose_neigh *neigh)
--
2.17.1
next reply other threads:[~2022-06-30 14:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-30 14:38 Duoming Zhou [this message]
2022-06-30 14:44 ` [PATCH net] net: rose: fix UAF bug caused by rose_t0timer_expiry Eric Dumazet
2022-06-30 15:08 ` duoming
2022-06-30 15:17 ` Eric Dumazet
2022-06-30 15:51 ` duoming
2022-06-30 16:07 ` Eric Dumazet
2022-07-01 5:14 ` duoming
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220630143842.24906-1-duoming@zju.edu.cn \
--to=duoming@zju.edu.cn \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=kuba@kernel.org \
--cc=linux-hams@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=ralf@linux-mips.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).