From: Daniel Borkmann <daniel@iogearbox.net>
To: Xiyu Yang <xiyuyang19@fudan.edu.cn>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Sitnicki <jakub@cloudflare.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Eric Dumazet <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
KP Singh <kpsingh@chromium.org>,
Lingpeng Chen <forrest0579@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: yuanxzhang@fudan.edu.cn, kjlu@umn.edu, Xin Tan <tanxin.ctf@gmail.com>
Subject: Re: [PATCH v2] bpf: Fix sk_psock refcnt leak when receiving message
Date: Mon, 27 Apr 2020 23:21:30 +0200 [thread overview]
Message-ID: <3d57b38c-fe77-4b2d-27e2-1b02c01226fb@iogearbox.net> (raw)
In-Reply-To: <1587872115-42805-1-git-send-email-xiyuyang19@fudan.edu.cn>
On 4/26/20 5:35 AM, Xiyu Yang wrote:
> tcp_bpf_recvmsg() invokes sk_psock_get(), which returns a reference of
> the specified sk_psock object to "psock" with increased refcnt.
>
> When tcp_bpf_recvmsg() returns, local variable "psock" becomes invalid,
> so the refcount should be decreased to keep refcount balanced.
>
> The reference counting issue happens in several exception handling paths
> of tcp_bpf_recvmsg(). When those error scenarios occur such as "flags"
> includes MSG_ERRQUEUE, the function forgets to decrease the refcnt
> increased by sk_psock_get(), causing a refcnt leak.
>
> Fix this issue by calling sk_psock_put() or pulling up the error queue
> read handling when those error scenarios occur.
>
> Fixes: e7a5f1f1cd000 ("bpf/sockmap: Read psock ingress_msg before sk_receive_queue")
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Applied, thanks!
prev parent reply other threads:[~2020-04-27 21:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-26 3:35 [PATCH v2] bpf: Fix sk_psock refcnt leak when receiving message Xiyu Yang
2020-04-26 11:01 ` Jakub Sitnicki
2020-04-27 21:21 ` Daniel Borkmann [this message]
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