* [Patch net] net_sched: check error pointer in tcf_dump_walker()
@ 2020-10-02 19:13 Cong Wang
2020-10-04 21:54 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Cong Wang @ 2020-10-02 19:13 UTC (permalink / raw)
To: netdev
Cc: Cong Wang, syzbot+b47bc4f247856fb4d9e1, Vlad Buslov,
Jamal Hadi Salim, Jiri Pirko
Although we take RTNL on dump path, it is possible to
skip RTNL on insertion path. So the following race condition
is possible:
rtnl_lock() // no rtnl lock
mutex_lock(&idrinfo->lock);
// insert ERR_PTR(-EBUSY)
mutex_unlock(&idrinfo->lock);
tc_dump_action()
rtnl_unlock()
So we have to skip those temporary -EBUSY entries on dump path
too.
Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
Cc: Vlad Buslov <vladbu@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
net/sched/act_api.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 5612b336e18e..798430e1a79f 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -235,6 +235,8 @@ static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
index++;
if (index < s_i)
continue;
+ if (IS_ERR(p))
+ continue;
if (jiffy_since &&
time_after(jiffy_since,
--
2.28.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Patch net] net_sched: check error pointer in tcf_dump_walker()
2020-10-02 19:13 [Patch net] net_sched: check error pointer in tcf_dump_walker() Cong Wang
@ 2020-10-04 21:54 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2020-10-04 21:54 UTC (permalink / raw)
To: xiyou.wangcong; +Cc: netdev, syzbot+b47bc4f247856fb4d9e1, vladbu, jhs, jiri
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Fri, 2 Oct 2020 12:13:34 -0700
> Although we take RTNL on dump path, it is possible to
> skip RTNL on insertion path. So the following race condition
> is possible:
>
> rtnl_lock() // no rtnl lock
> mutex_lock(&idrinfo->lock);
> // insert ERR_PTR(-EBUSY)
> mutex_unlock(&idrinfo->lock);
> tc_dump_action()
> rtnl_unlock()
>
> So we have to skip those temporary -EBUSY entries on dump path
> too.
>
> Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com
> Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
> Cc: Vlad Buslov <vladbu@mellanox.com>
> Cc: Jamal Hadi Salim <jhs@mojatatu.com>
> Cc: Jiri Pirko <jiri@resnulli.us>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Applied and queued up for -stable.
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2020-10-02 19:13 [Patch net] net_sched: check error pointer in tcf_dump_walker() Cong Wang
2020-10-04 21:54 ` David Miller
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