From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Andrey Ignatov <rdna@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
daniel@iogearbox.net, andrii.nakryiko@gmail.com,
kernel-team@fb.com
Subject: Re: [PATCH v3 bpf-next 1/4] bpf: implement bpf_link-based cgroup BPF program attachment
Date: Mon, 30 Mar 2020 17:38:33 -0700 [thread overview]
Message-ID: <20200331003833.2cimhnn5scfroyv7@ast-mbp> (raw)
In-Reply-To: <20200331000513.GA54465@rdna-mbp.dhcp.thefacebook.com>
On Mon, Mar 30, 2020 at 05:05:13PM -0700, Andrey Ignatov wrote:
> >
> > +#define BPF_LINK_CREATE_LAST_FIELD link_create.flags
> > +static int link_create(union bpf_attr *attr)
> > +{
>
> From what I see this function does not check any capability whether the
> existing bpf_prog_attach() checks for CAP_NET_ADMIN.
Great catch! It's a bug.
I fixed it up.
> This is pretty importnant difference but I don't see it clarified in the
> commit message or discussed (or I missed it?).
>
> Having a way to attach cgroup bpf prog by non-priv users is actually
> helpful in some use-cases, e.g. systemd required patching in the past to
> make it work with user (non-priv) sessions, see [0].
>
> But in other cases it's also useful to limit the ability to attach
> programs to a cgroup while using bpf_link so that only the thing that
> controls cgroup setup can attach but not any non-priv process running in
> that cgroup. How is this use-case covered in BPF_LINK_CREATE?
>
>
> [0] https://github.com/systemd/systemd/pull/12745
yeah. we need to resurrect the discussion around CAP_BPF.
PS
pls trim your replies.
next prev parent reply other threads:[~2020-03-31 0:38 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 2:59 [PATCH v3 bpf-next 0/4] Add support for cgroup bpf_link Andrii Nakryiko
2020-03-30 2:59 ` [PATCH v3 bpf-next 1/4] bpf: implement bpf_link-based cgroup BPF program attachment Andrii Nakryiko
2020-03-31 0:05 ` Andrey Ignatov
2020-03-31 0:38 ` Alexei Starovoitov [this message]
2020-03-31 1:06 ` Andrii Nakryiko
2020-03-30 2:59 ` [PATCH v3 bpf-next 2/4] bpf: implement bpf_prog replacement for an active bpf_cgroup_link Andrii Nakryiko
2020-03-30 3:00 ` [PATCH v3 bpf-next 3/4] libbpf: add support for bpf_link-based cgroup attachment Andrii Nakryiko
2020-03-30 3:00 ` [PATCH v3 bpf-next 4/4] selftests/bpf: test FD-based " Andrii Nakryiko
2020-03-30 14:49 ` [PATCH v3 bpf-next 0/4] Add support for cgroup bpf_link David Ahern
2020-03-30 20:20 ` Andrii Nakryiko
2020-03-30 20:45 ` David Ahern
2020-03-30 20:50 ` Alexei Starovoitov
2020-03-30 22:50 ` Alexei Starovoitov
2020-03-30 23:43 ` David Ahern
2020-03-31 0:32 ` Alexei Starovoitov
2020-03-31 0:57 ` David Ahern
2020-03-31 1:17 ` Alexei Starovoitov
2020-04-01 1:42 ` David Ahern
2020-04-01 2:04 ` Alexei Starovoitov
2020-03-31 3:54 ` Andrii Nakryiko
2020-03-31 16:54 ` David Ahern
2020-03-31 17:03 ` Andrii Nakryiko
2020-03-31 17:11 ` Alexei Starovoitov
2020-03-31 21:51 ` Edward Cree
2020-03-31 22:44 ` David Ahern
2020-04-01 0:45 ` Andrii Nakryiko
2020-04-01 0:22 ` Andrii Nakryiko
2020-04-01 14:26 ` Edward Cree
2020-04-01 17:39 ` Andrii Nakryiko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200331003833.2cimhnn5scfroyv7@ast-mbp \
--to=alexei.starovoitov@gmail.com \
--cc=andrii.nakryiko@gmail.com \
--cc=andriin@fb.com \
--cc=ast@fb.com \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kernel-team@fb.com \
--cc=netdev@vger.kernel.org \
--cc=rdna@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox