From: Song Liu <song@kernel.org>
To: John Fastabend <john.fastabend@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [bpf PATCH 1/9] bpf: sockmap/tls, during free we may call tcp_bpf_unhash() in loop
Date: Wed, 8 Jan 2020 17:34:21 -0800 [thread overview]
Message-ID: <CAPhsuW6CR20_81kkmp5k=h9uhZWMyLEwyeD2K5yd3RzK+pVgww@mail.gmail.com> (raw)
In-Reply-To: <157851804766.1732.2480524840189309989.stgit@ubuntu3-kvm2>
On Wed, Jan 8, 2020 at 1:14 PM John Fastabend <john.fastabend@gmail.com> wrote:
>
> When a sockmap is free'd and a socket in the map is enabled with tls
> we tear down the bpf context on the socket, the psock struct and state,
> and then call tcp_update_ulp(). The tcp_update_ulp() call is to inform
> the tls stack it needs to update its saved sock ops so that when the tls
> socket is later destroyed it doesn't try to call the now destroyed psock
> hooks.
>
> This is about keeping stacked ULPs in good shape so they always have
> the right set of stacked ops.
>
> However, recently unhash() hook was removed from TLS side. But, the
> sockmap/bpf side is not doing any extra work to update the unhash op
> when is torn down instead expecting TLS side to manage it. So both
> TLS and sockmap believe the other side is managing the op and instead
> no one updates the hook so it continues to point at tcp_bpf_unhash().
> When unhash hook is called we call tcp_bpf_unhash() which detects the
> psock has already been destroyed and calls sk->sk_prot_unhash() which
> calls tcp_bpf_unhash() yet again and so on looping and hanging the core.
>
> To fix have sockmap tear down logic fixup the stale pointer.
>
> Fixes: 5d92e631b8be ("net/tls: partially revert fix transition through disconnect with close")
> Reported-by: syzbot+83979935eb6304f8cd46@syzkaller.appspotmail.com
> Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Song Liu <songliubraving@fb.com>
next prev parent reply other threads:[~2020-01-09 1:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 21:13 [bpf PATCH 0/9] Fixes for sockmap/tls from more complex BPF progs John Fastabend
2020-01-08 21:14 ` [bpf PATCH 1/9] bpf: sockmap/tls, during free we may call tcp_bpf_unhash() in loop John Fastabend
2020-01-09 1:34 ` Song Liu [this message]
2020-01-08 21:14 ` [bpf PATCH 2/9] bpf: sockmap, ensure sock lock held during tear down John Fastabend
2020-01-09 17:10 ` Song Liu
2020-01-08 21:14 ` [bpf PATCH 3/9] bpf: sockmap/tls, push write_space updates through ulp updates John Fastabend
2020-01-09 10:33 ` Jakub Sitnicki
2020-01-09 21:22 ` John Fastabend
2020-01-10 13:40 ` Jakub Sitnicki
2020-01-08 21:14 ` [bpf PATCH 4/9] bpf: sockmap, skmsg helper overestimates push, pull, and pop bounds John Fastabend
2020-01-09 18:37 ` Song Liu
2020-01-08 21:15 ` [bpf PATCH 5/9] bpf: sockmap/tls, msg_push_data may leave end mark in place John Fastabend
2020-01-09 18:51 ` Song Liu
2020-01-08 21:15 ` [bpf PATCH 6/9] bpf: sockmap/tls, tls_sw can create a plaintext buf > encrypt buf John Fastabend
2020-01-09 23:04 ` Jonathan Lemon
2020-01-08 21:15 ` [bpf PATCH 7/9] bpf: sockmap/tls, skmsg can have wrapped skmsg that needs extra chaining John Fastabend
2020-01-09 23:13 ` Jonathan Lemon
2020-01-08 21:16 ` [bpf PATCH 8/9] bpf: sockmap/tls, tls_push_record can not handle zero length skmsg John Fastabend
2020-01-09 20:08 ` Song Liu
2020-01-09 21:25 ` John Fastabend
2020-01-10 23:20 ` John Fastabend
2020-01-08 21:16 ` [bpf PATCH 9/9] bpf: sockmap/tls, fix pop data with SK_DROP return code John Fastabend
2020-01-09 23:28 ` Jonathan Lemon
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