From: Yonghong Song <yhs@meta.com>
To: Hou Tao <houtao@huaweicloud.com>,
bpf@vger.kernel.org, Martin KaFai Lau <martin.lau@linux.dev>,
Hao Luo <haoluo@google.com>, Yonghong Song <yhs@fb.com>
Cc: Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Jiri Olsa <jolsa@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
houtao1@huawei.com
Subject: Re: [PATCH bpf-next v3 1/3] bpf: Pin the start cgroup in cgroup_iter_seq_init()
Date: Mon, 21 Nov 2022 08:27:09 -0800 [thread overview]
Message-ID: <29a89827-0922-7520-6540-edc0c07f7fd9@meta.com> (raw)
In-Reply-To: <20221121073440.1828292-2-houtao@huaweicloud.com>
On 11/20/22 11:34 PM, Hou Tao wrote:
> From: Hou Tao <houtao1@huawei.com>
>
> bpf_iter_attach_cgroup() has already acquired an extra reference for the
> start cgroup, but the reference may be released if the iterator link fd
> is closed after the creation of iterator fd, and it may lead to
> user-after-free problem when reading the iterator fd.
>
> An alternative fix is pinning iterator link when opening iterator,
> but it will make iterator link being still visible after the close of
> iterator link fd and the behavior is different with other link types, so
> just fixing it by acquiring another reference for the start cgroup.
>
> Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter")
> Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
next prev parent reply other threads:[~2022-11-21 16:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 7:34 [PATCH bpf-next v3 0/3] bpf: Pin the start cgroup for cgroup iterator Hou Tao
2022-11-21 7:34 ` [PATCH bpf-next v3 1/3] bpf: Pin the start cgroup in cgroup_iter_seq_init() Hou Tao
2022-11-21 16:27 ` Yonghong Song [this message]
2022-11-21 7:34 ` [PATCH bpf-next v3 2/3] selftests/bpf: Add cgroup helper remove_cgroup() Hou Tao
2022-11-21 7:34 ` [PATCH bpf-next v3 3/3] selftests/bpf: Add test for cgroup iterator on a dead cgroup Hou Tao
2022-11-21 16:50 ` [PATCH bpf-next v3 0/3] bpf: Pin the start cgroup for cgroup iterator patchwork-bot+netdevbpf
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