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From: Paolo Abeni <pabeni@redhat.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>, Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
	Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
	Davide Caratti <dcaratti@redhat.com>,
	xiyou.wangcong@gmail.com,  jiri@resnulli.us,
	shmulik.ladkani@gmail.com
Subject: Re: [PATCH net] net/sched: act_mirred: use the backlog for mirred ingress
Date: Tue, 13 Feb 2024 12:06:04 +0100	[thread overview]
Message-ID: <93a346087193c57f4df807c478d0f7fc8e7db6aa.camel@redhat.com> (raw)
In-Reply-To: <CAM0EoMnYyyf7Zpa9eUFBU1vzx5QrUhFfXSFH4_utXOPU4+YFxQ@mail.gmail.com>

On Mon, 2024-02-12 at 10:11 -0500, Jamal Hadi Salim wrote:
> On Mon, Feb 12, 2024 at 9:51 AM Jamal Hadi Salim <jhs@mojatatu.com> wrote:
> > 
> > On Fri, Feb 9, 2024 at 6:54 PM Jakub Kicinski <kuba@kernel.org> wrote:
> > > 
> > > The test Davide added in commit ca22da2fbd69 ("act_mirred: use the backlog
> > > for nested calls to mirred ingress") hangs our testing VMs every 10 or so
> > > runs, with the familiar tcp_v4_rcv -> tcp_v4_rcv deadlock reported by
> > > lockdep.
> > > 
> > > In the past there was a concern that the backlog indirection will
> > > lead to loss of error reporting / less accurate stats. But the current
> > > workaround does not seem to address the issue.
> > > 
> > 
> > Let us run some basic tests on this first - it's a hairy spot. Also,
> 
> Something broke.
> Create a ns. Put one half of veth into the namespace. Create a filter
> inside the net ns.
> at_ns$ tc qdisc add dev port0 ingress_block 21 clsact
> at_ns$ tc filter add block 21 egress protocol ip prio 10 matchall
> action mirred ingress redirect dev port0
> 
> Send a ping from host:
> at_host@ ping 10.0.0.2 -c 1 -I <vethportonhostside>
> 
> And.. hits uaf.... see attached.

It looks like:

netif_receive_skb
run_tc()
	act_mirred	
		netif_receive_skb
			sch_handle_ingress
				act_mirred // nesting limit hit
			// free skb
		// netif_receive_skb returns NET_RX_DROP
	// act_mirred returns TC_ACT_SHOT
// UaF while de-referencing the (freed) skb


No idea how to solve it on top of my mind :(

Cheers,

Paolo


  reply	other threads:[~2024-02-13 11:06 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-09 23:54 [PATCH net] net/sched: act_mirred: use the backlog for mirred ingress Jakub Kicinski
2024-02-12 14:51 ` Jamal Hadi Salim
2024-02-12 15:02   ` Jakub Kicinski
2024-02-12 15:11   ` Jamal Hadi Salim
2024-02-13 11:06     ` Paolo Abeni [this message]
2024-02-14  0:27       ` Jakub Kicinski
2024-02-14  3:40         ` Jakub Kicinski
2024-02-14 15:11 ` Jamal Hadi Salim
2024-02-14 15:28   ` Jamal Hadi Salim
2024-02-14 16:10     ` Davide Caratti
2024-02-15  0:31       ` Jakub Kicinski
2024-02-15 17:55         ` Davide Caratti
  -- strict thread matches above, loose matches on Subject: below --
2022-09-23 15:11 Davide Caratti
2022-09-25 18:08 ` Cong Wang
2022-10-04 17:40   ` Davide Caratti
2022-10-16 17:28     ` Cong Wang
2022-11-18 23:07 ` Peilin Ye

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