From: David Miller <davem@davemloft.net>
To: code@rkapl.cz
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH v2] net: sched: fix crash when deleting secondary chains
Date: Fri, 24 Nov 2017 01:27:16 +0900 (KST) [thread overview]
Message-ID: <20171124.012716.1134458426501486126.davem@davemloft.net> (raw)
In-Reply-To: <20171119173632.13125-1-code@rkapl.cz>
From: Roman Kapl <code@rkapl.cz>
Date: Mon, 20 Nov 2017 22:21:13 +0100
> If you flush (delete) a filter chain other than chain 0 (such as when
> deleting the device), the kernel may run into a use-after-free. The
> chain refcount must not be decremented unless we are sure we are done
> with the chain.
>
> To reproduce the bug, run:
> ip link add dtest type dummy
> tc qdisc add dev dtest ingress
> tc filter add dev dtest chain 1 parent ffff: flower
> ip link del dtest
>
> Introduced in: commit f93e1cdcf42c ("net/sched: fix filter flushing"),
> but unless you have KAsan or luck, you won't notice it until
> commit 0dadc117ac8b ("cls_flower: use tcf_exts_get_net() before call_rcu()")
>
> Fixes: f93e1cdcf42c ("net/sched: fix filter flushing")
> Acked-by: Jiri Pirko <jiri@mellanox.com>
> Signed-off-by: Roman Kapl <code@rkapl.cz>
Applied, thank you.
prev parent reply other threads:[~2017-11-23 16:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-20 21:21 [PATCH v2] net: sched: fix crash when deleting secondary chains Roman Kapl
2017-11-20 19:16 ` Cong Wang
2017-11-23 16:27 ` David Miller [this message]
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