netdev - Re: [PATCH bpf 2/2] bpf, sockmap: fix psock refcount leak in bpf_tcp

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Message-ID: <5677fb82-f248-894a-5214-466b725710bd@gmail.com>
Date:   Fri, 24 Aug 2018 17:29:51 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Daniel Borkmann <daniel@...earbox.net>,
        alexei.starovoitov@...il.com
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH bpf 2/2] bpf, sockmap: fix psock refcount leak in
 bpf_tcp_recvmsg

On 08/24/2018 01:08 PM, Daniel Borkmann wrote:
> In bpf_tcp_recvmsg() we first took a reference on the psock, however
> once we find that there are skbs in the normal socket's receive queue
> we return with processing them through tcp_recvmsg(). Problem is that
> we leak the taken reference on the psock in that path. Given we don't
> really do anything with the psock at this point, move the skb_queue_empty()
> test before we fetch the psock to fix this case.
> 
> Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support")
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> ---

Oops. Thanks for catching this, all of our use cases and tests
to this point either always did redirect or normal receive and
I missed the mixed case. I'll write a tests for bpf-next to also
ensure we catch anything else.

Thanks.

Acked-by: John Fastabend <john.fastabend@...il.com>