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From: Lorenz Bauer <lmb@cloudflare.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Song Liu <songliubraving@fb.com>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <kernel-team@fb.com>, Jann Horn <jannh@google.com>,
	gregkh@linuxfoundation.org, linux-abi@vger.kernel.org,
	kees@chromium.org
Subject: Re: [PATCH v2 bpf-next 1/4] bpf: unprivileged BPF access via /dev/bpf
Date: Fri, 28 Jun 2019 10:05:56 +0100	[thread overview]
Message-ID: <CACAyw9-AXy9UFdGkDaaNxw9T8meB+NAH5Yp_0G3nuw1AN5impQ@mail.gmail.com> (raw)
In-Reply-To: <21894f45-70d8-dfca-8c02-044f776c5e05@kernel.org>

On Fri, 28 Jun 2019 at 00:40, Andy Lutomirski <luto@kernel.org> wrote:
>
> I have a bigger issue with this patch, though: it's a really awkward way
> to pretend to have capabilities.  For bpf, it seems like you could make
> this be a *real* capability without too much pain since there's only one
> syscall there.  Just find a way to pass an fd to /dev/bpf into the
> syscall.  If this means you need a new bpf_with_cap() syscall that takes
> an extra argument, so be it.  The old bpf() syscall can just translate
> to bpf_with_cap(..., -1).

I agree, this seems nicer from my POV, since it evades the issues with
the Go runtime I pointed out in the other message.

It also seems like this wouldn't have to create API churn in libbpf? We can
"feature detect" the presence of the new syscall and use that instead. If
you want you can even keep the semantics of having a "global" credential.

-- 
Lorenz Bauer  |  Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK

www.cloudflare.com

  parent reply	other threads:[~2019-06-28  9:06 UTC|newest]

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-27 20:19 [PATCH v2 bpf-next 0/4] sys_bpf() access control via /dev/bpf Song Liu
2019-06-27 20:19 ` [PATCH v2 bpf-next 1/4] bpf: unprivileged BPF access " Song Liu
2019-06-27 23:40   ` Andy Lutomirski
2019-06-27 23:42     ` Andy Lutomirski
2019-06-28 10:28       ` Christian Brauner
2019-06-28  9:05     ` Lorenz Bauer [this message]
2019-06-28 19:04     ` Song Liu
2019-06-30  0:12       ` Andy Lutomirski
2019-07-01  9:03         ` Song Liu
2019-07-02  1:59           ` Andy Lutomirski
2019-07-02 18:24             ` Kees Cook
2019-07-02 21:32               ` Andy Lutomirski
2019-07-02 23:48                 ` Song Liu
2019-07-22 20:53                 ` Song Liu
2019-07-23 10:45                   ` Lorenz Bauer
2019-07-23 15:11                   ` Andy Lutomirski
2019-07-23 22:56                     ` Song Liu
2019-07-24  1:40                       ` Andy Lutomirski
2019-07-24  6:30                         ` Song Liu
2019-07-27 18:20                           ` Song Liu
2019-07-30  5:07                             ` Song Liu
2019-07-30 20:24                               ` Andy Lutomirski
2019-07-31  8:10                                 ` Song Liu
2019-07-31 19:09                                   ` Andy Lutomirski
2019-08-02  7:21                                     ` Song Liu
2019-08-04 22:16                                       ` Andy Lutomirski
2019-08-05  0:08                                         ` Andy Lutomirski
2019-08-05  5:47                                           ` Andy Lutomirski
2019-08-05  7:36                                             ` Song Liu
2019-08-05 17:23                                               ` Andy Lutomirski
2019-08-05 19:21                                                 ` Alexei Starovoitov
2019-08-05 21:25                                                   ` Andy Lutomirski
2019-08-05 22:21                                                     ` Andy Lutomirski
2019-08-06  1:11                                                     ` Alexei Starovoitov
2019-08-07  5:24                                                       ` Andy Lutomirski
2019-08-07  9:03                                                         ` Lorenz Bauer
2019-08-07 13:52                                                           ` Andy Lutomirski
2019-08-13 21:58                                                         ` Alexei Starovoitov
2019-08-13 22:26                                                           ` Daniel Colascione
2019-08-13 23:24                                                             ` Andy Lutomirski
2019-08-13 23:06                                                           ` Andy Lutomirski
2019-08-14  0:57                                                             ` Alexei Starovoitov
2019-08-14 17:51                                                               ` Andy Lutomirski
2019-08-14 22:05                                                                 ` Alexei Starovoitov
2019-08-14 22:30                                                                   ` Andy Lutomirski
2019-08-14 23:33                                                                     ` Alexei Starovoitov
2019-08-14 23:59                                                                       ` Andy Lutomirski
2019-08-15  0:36                                                                         ` Alexei Starovoitov
2019-08-15 11:24                                                                   ` Jordan Glover
2019-08-15 17:28                                                                     ` Alexei Starovoitov
2019-08-15 18:36                                                                       ` Andy Lutomirski
2019-08-15 23:08                                                                         ` Alexei Starovoitov
2019-08-16  9:34                                                                           ` Jordan Glover
2019-08-16  9:59                                                                             ` Thomas Gleixner
2019-08-16 11:33                                                                               ` Jordan Glover
2019-08-16 19:52                                                                                 ` Alexei Starovoitov
2019-08-16 20:28                                                                                   ` Thomas Gleixner
2019-08-17 15:02                                                                                     ` Alexei Starovoitov
2019-08-17 15:44                                                                                       ` Andy Lutomirski
2019-08-19  9:15                                                                                       ` Thomas Gleixner
2019-08-19 17:27                                                                                         ` Alexei Starovoitov
2019-08-19 17:38                                                                                           ` Andy Lutomirski
2019-08-15 18:43                                                                       ` Jordan Glover
2019-08-15 19:46                                                           ` Kees Cook
2019-08-15 23:46                                                             ` Alexei Starovoitov
2019-08-16  0:54                                                               ` Andy Lutomirski
2019-08-16  5:56                                                                 ` Song Liu
2019-08-16 21:45                                                                 ` Alexei Starovoitov
2019-08-16 22:22                                                                   ` Christian Brauner
2019-08-17 15:08                                                                     ` Alexei Starovoitov
2019-08-17 15:16                                                                       ` Christian Brauner
2019-08-17 15:36                                                                         ` Alexei Starovoitov
2019-08-17 15:42                                                                           ` Christian Brauner
2019-08-22 14:17                                                         ` Daniel Borkmann
2019-08-22 15:16                                                           ` Andy Lutomirski
2019-08-22 15:17                                                             ` RFC: very rough draft of a bpf permission model Andy Lutomirski
2019-08-22 23:26                                                               ` Alexei Starovoitov
2019-08-23 23:09                                                                 ` Andy Lutomirski
2019-08-26 22:36                                                                   ` Alexei Starovoitov
2019-08-27  0:05                                                                     ` Andy Lutomirski
2019-08-27  0:34                                                                       ` Alexei Starovoitov
2019-08-22 22:48                                                           ` [PATCH v2 bpf-next 1/4] bpf: unprivileged BPF access via /dev/bpf Alexei Starovoitov
2019-07-30 20:20                             ` Andy Lutomirski
2019-07-31  7:44                               ` Song Liu
2019-06-28  9:01   ` Lorenz Bauer
2019-06-28 19:10     ` Song Liu
2019-07-01  9:34       ` Lorenz Bauer
2019-07-02 19:22   ` Andrii Nakryiko
2019-07-03  7:28     ` Greg KH
2019-06-27 20:19 ` [PATCH v2 bpf-next 2/4] bpf: sync tools/include/uapi/linux/bpf.h Song Liu
2019-06-27 20:19 ` [PATCH v2 bpf-next 3/4] libbpf: add libbpf_[enable|disable]_sys_bpf() Song Liu
2019-06-27 20:19 ` [PATCH v2 bpf-next 4/4] bpftool: use libbpf_[enable|disable]_sys_bpf() Song Liu

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