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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Edward Cree <ecree@solarflare.com>
Cc: "David Ahern" <dsahern@gmail.com>,
	"Lorenz Bauer" <lmb@cloudflare.com>,
	"Andrii Nakryiko" <andrii.nakryiko@gmail.com>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Andrii Nakryiko" <andriin@fb.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Andrey Ignatov" <rdna@fb.com>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next 1/4] xdp: Support specifying expected existing program when attaching XDP
Date: Mon, 30 Mar 2020 20:43:19 -0700	[thread overview]
Message-ID: <20200331034319.lg2tgxxs5eyiqebi@ast-mbp> (raw)
In-Reply-To: <eba2b6df-e2e8-e756-dead-3f1044a061cd@solarflare.com>

On Mon, Mar 30, 2020 at 04:25:07PM +0100, Edward Cree wrote:
> On 27/03/2020 23:02, Alexei Starovoitov wrote:
> > On Fri, Mar 27, 2020 at 10:12:05AM -0600, David Ahern wrote:
> >> I had a thought yesterday along similar lines: bpf_link is about
> >> ownership and preventing "accidental" deletes.
> > The mechanism for "human override" is tbd.
> Then that's a question you really need to solve, especially if you're
>  going to push bpf_link quite so... forcefully.
> Everything that a human operator can do, so can any program with the
>  same capabilities/wheel bits.  Especially as the API that the
>  operator-tool uses *will* be open and documented.  The Unix Way does
>  not allow unscriptable interfaces, and heavily frowns at any kind of
>  distinction between 'humans' and 'programs'.

can you share a link on such philosophy?
I was thinking something like CAPTCHA 'confirm if you're not a robot'
type of a button.
So humans doing 'bpftool link show' followed by 'bpftool link del id 123'
will work as expected, but processes cannot use the same api to
nuke other processes.

> So what will the override look like?  A bpf() syscall with a special
>  BPF_F_IM_A_HUMAN_AND_I_KNOW_WHAT_IM_DOING flag?  ptracing the link
>  owner, so that you can close() its fd?  Something in between?

not sure yet.

> In any case, the question is orthogonal to the bpf_link vs. netlink
>  issue: the netlink XDP attach could be done with a flag that means
>  "don't allow replacement/removal without EXPECTED_FD".  No?

Nothing to do with netlink, of course. Both XDP and tc bpf hooks
missing the concept of owner of the attachment.
For tc it's easier to implement and understand, since it allows
multi prog. If process A attaches a tc clsbpf prog via bpf_link
another process B will not be able to nuke it.

  reply	other threads:[~2020-03-31  3:43 UTC|newest]

Thread overview: 120+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19 13:13 [PATCH bpf-next 0/4] XDP: Support atomic replacement of XDP interface attachments Toke Høiland-Jørgensen
2020-03-19 13:13 ` [PATCH bpf-next 1/4] xdp: Support specifying expected existing program when attaching XDP Toke Høiland-Jørgensen
2020-03-19 22:52   ` Jakub Kicinski
2020-03-20  8:48     ` Toke Høiland-Jørgensen
2020-03-20 17:35       ` Jakub Kicinski
2020-03-20 18:17         ` Toke Høiland-Jørgensen
2020-03-20 18:35           ` Jakub Kicinski
2020-03-20 18:30         ` John Fastabend
2020-03-20 20:24           ` Andrii Nakryiko
2020-03-23 11:24             ` Toke Høiland-Jørgensen
2020-03-23 16:54               ` Jakub Kicinski
2020-03-23 18:14               ` Andrii Nakryiko
2020-03-23 19:23                 ` Toke Høiland-Jørgensen
2020-03-24  1:01                   ` David Ahern
2020-03-24  4:53                     ` Andrii Nakryiko
2020-03-24 20:55                       ` David Ahern
2020-03-24 22:56                         ` Andrii Nakryiko
2020-03-24  5:00                   ` Andrii Nakryiko
2020-03-24 10:57                     ` Toke Høiland-Jørgensen
2020-03-24 18:53                       ` Jakub Kicinski
2020-03-24 22:30                         ` Andrii Nakryiko
2020-03-25  1:25                           ` Jakub Kicinski
2020-03-24 19:22                       ` John Fastabend
2020-03-25  1:36                         ` Alexei Starovoitov
2020-03-25  2:15                           ` Jakub Kicinski
2020-03-25 18:06                             ` Alexei Starovoitov
2020-03-25 18:20                               ` Jakub Kicinski
2020-03-25 19:14                                 ` Alexei Starovoitov
2020-03-25 10:42                           ` Toke Høiland-Jørgensen
2020-03-25 18:11                             ` Alexei Starovoitov
2020-03-25 10:30                         ` Toke Høiland-Jørgensen
2020-03-25 17:56                           ` Alexei Starovoitov
2020-03-24 22:25                       ` Andrii Nakryiko
2020-03-25  9:38                         ` Toke Høiland-Jørgensen
2020-03-25 17:55                           ` Alexei Starovoitov
2020-03-26  0:16                           ` Andrii Nakryiko
2020-03-26  5:13                             ` Jakub Kicinski
2020-03-26 18:09                               ` Andrii Nakryiko
2020-03-26 19:40                               ` Alexei Starovoitov
2020-03-26 20:05                                 ` Edward Cree
2020-03-27 11:09                                   ` Lorenz Bauer
2020-03-27 23:11                                   ` Alexei Starovoitov
2020-03-26 10:04                             ` Lorenz Bauer
2020-03-26 17:47                               ` Jakub Kicinski
2020-03-26 19:45                                 ` Alexei Starovoitov
2020-03-26 18:18                               ` Andrii Nakryiko
2020-03-26 19:53                               ` Alexei Starovoitov
2020-03-27 11:11                                 ` Toke Høiland-Jørgensen
2020-04-02 20:21                                   ` bpf: ability to attach freplace to multiple parents Alexei Starovoitov
2020-04-02 21:23                                     ` Toke Høiland-Jørgensen
2020-04-02 21:54                                       ` Alexei Starovoitov
2020-04-03  8:38                                         ` Toke Høiland-Jørgensen
2020-04-07  1:44                                           ` Alexei Starovoitov
2020-04-07  9:20                                             ` Toke Høiland-Jørgensen
2020-05-12  8:34                                         ` Toke Høiland-Jørgensen
2020-05-12  9:53                                           ` Alan Maguire
2020-05-12 13:02                                             ` Toke Høiland-Jørgensen
2020-05-12 23:18                                             ` Alexei Starovoitov
2020-05-12 23:06                                           ` Alexei Starovoitov
2020-05-13 10:25                                             ` Toke Høiland-Jørgensen
2020-04-02 21:24                                     ` Andrey Ignatov
2020-04-02 22:01                                       ` Alexei Starovoitov
2020-03-26 12:35                             ` [PATCH bpf-next 1/4] xdp: Support specifying expected existing program when attaching XDP Toke Høiland-Jørgensen
2020-03-26 19:06                               ` Andrii Nakryiko
2020-03-27 11:06                                 ` Lorenz Bauer
2020-03-27 16:12                                   ` David Ahern
2020-03-27 20:10                                     ` Andrii Nakryiko
2020-03-27 23:02                                     ` Alexei Starovoitov
2020-03-30 15:25                                       ` Edward Cree
2020-03-31  3:43                                         ` Alexei Starovoitov [this message]
2020-03-31 22:05                                           ` Edward Cree
2020-03-31 22:16                                             ` Alexei Starovoitov
2020-03-27 19:42                                   ` Andrii Nakryiko
2020-03-27 19:45                                   ` Andrii Nakryiko
2020-03-27 23:09                                   ` Alexei Starovoitov
2020-03-27 11:46                                 ` Toke Høiland-Jørgensen
2020-03-27 20:07                                   ` Andrii Nakryiko
2020-03-27 22:16                                     ` Toke Høiland-Jørgensen
2020-03-27 22:54                                       ` Andrii Nakryiko
2020-03-28  1:09                                         ` Toke Høiland-Jørgensen
2020-03-28  1:44                                           ` Andrii Nakryiko
2020-03-28 19:43                                             ` Toke Høiland-Jørgensen
2020-03-26 19:58                               ` Alexei Starovoitov
2020-03-27 12:06                                 ` Toke Høiland-Jørgensen
2020-03-27 23:00                                   ` Alexei Starovoitov
2020-03-28  1:43                                     ` Toke Høiland-Jørgensen
2020-03-28  2:26                                       ` Alexei Starovoitov
2020-03-28 19:34                                         ` Toke Høiland-Jørgensen
2020-03-28 23:35                                           ` Alexei Starovoitov
2020-03-29 10:39                                             ` Toke Høiland-Jørgensen
2020-03-29 19:26                                               ` Alexei Starovoitov
2020-03-30 10:19                                                 ` Toke Høiland-Jørgensen
2020-03-29 20:23                                           ` Andrii Nakryiko
2020-03-30 13:53                                             ` Toke Høiland-Jørgensen
2020-03-30 20:17                                               ` Andrii Nakryiko
2020-03-31 10:13                                                 ` Toke Høiland-Jørgensen
2020-03-31 13:48                                                   ` Daniel Borkmann
2020-03-31 15:00                                                     ` Toke Høiland-Jørgensen
2020-03-31 20:19                                                       ` Andrii Nakryiko
2020-03-31 20:15                                                     ` Andrii Nakryiko
2020-03-30 15:41                                             ` Edward Cree
2020-03-30 19:13                                               ` Jakub Kicinski
2020-03-31  4:01                                               ` Alexei Starovoitov
2020-03-31 11:34                                                 ` Toke Høiland-Jørgensen
2020-03-31 18:52                                                   ` Alexei Starovoitov
2020-03-20 20:30       ` Daniel Borkmann
2020-03-20 20:40         ` Daniel Borkmann
2020-03-20 21:30           ` Jakub Kicinski
2020-03-20 21:55             ` Daniel Borkmann
2020-03-20 23:35               ` Jakub Kicinski
2020-03-20 20:39       ` Andrii Nakryiko
2020-03-23 11:25         ` Toke Høiland-Jørgensen
2020-03-23 18:07           ` Andrii Nakryiko
2020-03-23 23:54           ` Andrey Ignatov
2020-03-24 10:16             ` Toke Høiland-Jørgensen
2020-03-20  2:13   ` Yonghong Song
2020-03-20  8:48     ` Toke Høiland-Jørgensen
2020-03-19 13:13 ` [PATCH bpf-next 2/4] tools: Add EXPECTED_FD-related definitions in if_link.h Toke Høiland-Jørgensen
2020-03-19 13:13 ` [PATCH bpf-next 3/4] libbpf: Add function to set link XDP fd while specifying old fd Toke Høiland-Jørgensen
2020-03-19 13:13 ` [PATCH bpf-next 4/4] selftests/bpf: Add tests for attaching XDP programs Toke Høiland-Jørgensen

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