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From: ebiederm@xmission.com (Eric W. Biederman)
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <ast@kernel.org>,
	David Miller <davem@davemloft.net>,
	Al Viro <viro@zeniv.linux.org.uk>, bpf <bpf@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Gary Lin <GLin@suse.com>, Bruno Meneguele <bmeneg@redhat.com>
Subject: Re: [RFC][PATCH] net/bpfilter: Remove this broken and apparently unmantained
Date: Sun, 07 Jun 2020 11:09:52 -0500
Message-ID: <87zh9e6enj.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <CAHk-=wiUjZV5VmdqUOGjpNMmobGQKyZpaa=MuJ-5XM3Da86zBg@mail.gmail.com> (Linus Torvalds's message of "Sat, 6 Jun 2020 19:19:56 -0700")

Linus Torvalds <torvalds@linux-foundation.org> writes:

> On Sat, Jun 6, 2020 at 6:49 PM Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
>>>
>> I'm not aware of execve issues. I don't remember being cc-ed on them.
>> To me this 'lets remove everything' patch comes out of nowhere with
>> a link to three month old patch as a justification.
>
> Well, it's out of nowhere as far as bpf is concerned, but we've had a
> fair amount of discussions about execve cleanups (and a fair amount of
> work too, not just discussion) lately
>
> So it comes out of "execve is rather grotty", and trying to make it
> simpler have fewer special cases.
>
>> So far we had two attempts at converting netfilter rules to bpf. Both ended up
>> with user space implementation and short cuts.
>
> So I have a question: are we convinced that doing this "netfilter
> conversion" in user space is required at all?
>
> I realize that yes, running clang is not something we'd want to do in
> kernel space, that's not what I'm asking.
>
> But how much might be doable at kernel compile time (run clang to
> generate bpf statically when building the kernel) together with some
> simplistic run-time parameterized JITting for the table details that
> the kernel could do on its own without a real compiler?
>
> Because the problem with this code isn't the "use bpf for netfilter
> rules", it's the "run a user mode helper". The execve thing is
> actually only incidental, it also ends up being a somewhat interesting
> issue wrt namespacing and security (and bootstrapping - I'm not
> convinced people want to have a clang bpf compiler in initrd etc).
>
> So particularly if we accept the fact that we won't necessarily need
> all of netfilter converted in general - some will be just translated
> entirely independently in user space and not use netfilter at all
> (just bpf loaded normally)
>
> IOW there would potentially only be a (fairly small?) core set that
> the kernel would need to be able to handle "natively".
>
> Am I just blathering?

I wish I could answer you.

All the code does at this time is connect some ipv4 bpfilter specific
setsockopt commands to a usermode helper with a read pipe and a write
pipe.  The userspace portion does absolutely nothing with those
commands.

I don't have the foggiest idea what that code hopes to be doing when
that code is fully fleshed out.

If the goal is to become a backwards compatible compiler from historic
netfilter commands to bpf it isn't the craziest design in the world.
But that isn't what is implemented today.

With no users it just isn't clear what the code needs to be doing so I
can't tell what needs to be done to bugs in the code.  I can't answer
which behaviors do the users care about.

Eric

  reply index

Thread overview: 193+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200329005528.xeKtdz2A0%akpm@linux-foundation.org>
     [not found] ` <13fb3ab7-9ab1-b25f-52f2-40a6ca5655e1@i-love.sakura.ne.jp>
     [not found]   ` <202006051903.C44988B@keescook>
2020-06-06 19:20     ` Eric W. Biederman
2020-06-06 20:19       ` Alexei Starovoitov
2020-06-06 22:33         ` Linus Torvalds
2020-06-07  1:49           ` Alexei Starovoitov
2020-06-07  2:19             ` Linus Torvalds
2020-06-07 16:09               ` Eric W. Biederman [this message]
2020-06-08 16:20               ` Alexei Starovoitov
2020-06-08 16:40                 ` Greg KH
2020-06-08 18:35                 ` Kees Cook
2020-06-09  1:26                   ` Alexei Starovoitov
2020-06-09 15:37                     ` Kees Cook
2020-06-09 19:51                 ` Eric W. Biederman
2020-06-07  2:31             ` Tetsuo Handa
2020-06-08 16:23               ` Alexei Starovoitov
2020-06-08 23:22                 ` Tetsuo Handa
2020-06-09  1:28                   ` Alexei Starovoitov
2020-06-09  5:29                     ` Tetsuo Handa
2020-06-09 22:32                       ` Alexei Starovoitov
2020-06-09 23:30                         ` Tetsuo Handa
2020-06-10  0:05                           ` Alexei Starovoitov
2020-06-10  3:08                             ` Tetsuo Handa
2020-06-10  3:32                               ` Alexei Starovoitov
2020-06-10  7:30                                 ` Tetsuo Handa
2020-06-10 16:24                                   ` Casey Schaufler
2020-06-09 20:02                 ` Eric W. Biederman
2020-06-09 23:56                   ` Alexei Starovoitov
2020-06-10 21:12                     ` Eric W. Biederman
2020-06-11 23:31                       ` Alexei Starovoitov
2020-06-12  0:57                         ` Tetsuo Handa
2020-06-13  3:38                           ` Alexei Starovoitov
2020-06-13  4:22                             ` Tetsuo Handa
2020-06-13 14:08                         ` Eric W. Biederman
2020-06-13 15:33                           ` Alexei Starovoitov
2020-06-13 16:14                             ` Alexei Starovoitov
2020-06-14 14:51                               ` Eric W. Biederman
2020-06-16  1:55                                 ` Alexei Starovoitov
2020-06-16 16:21                                   ` Alexei Starovoitov
2020-06-23 18:04                                   ` Eric W. Biederman
2020-06-23 18:35                                     ` Alexei Starovoitov
2020-06-23 18:53                                       ` Eric W. Biederman
2020-06-23 19:40                                         ` Alexei Starovoitov
2020-06-24  1:51                                           ` Tetsuo Handa
2020-06-24  4:00                                             ` Alexei Starovoitov
2020-06-24  4:58                                               ` Tetsuo Handa
2020-06-24  6:39                                                 ` Alexei Starovoitov
2020-06-24  7:05                                                   ` Tetsuo Handa
2020-06-24 15:41                                                     ` Casey Schaufler
2020-06-24 17:54                                                       ` Alexei Starovoitov
2020-06-24 19:48                                                         ` Casey Schaufler
2020-06-24  6:05                                               ` Alexei Starovoitov
2020-06-24 14:18                                                 ` Alexei Starovoitov
2020-06-24 12:13                                           ` Eric W. Biederman
2020-06-24 14:26                                             ` Alexei Starovoitov
2020-06-24 23:14                                               ` Tetsuo Handa
2020-06-25  1:35                                                 ` Alexei Starovoitov
2020-06-25  6:38                                                   ` Tetsuo Handa
2020-06-25  9:57                                                     ` Greg KH
2020-06-25 11:03                                                       ` Tetsuo Handa
2020-06-25 12:07                                                         ` Greg KH
2020-06-25 14:21                                                           ` Tetsuo Handa
2020-06-25 19:34                                                           ` David Miller
2020-06-26  1:36                                                             ` Linus Torvalds
2020-06-26  1:51                                                               ` Alexei Starovoitov
2020-06-26  4:58                                                                 ` Tetsuo Handa
2020-06-26  5:41                                                                   ` Alexei Starovoitov
2020-06-26  6:20                                                                     ` Tetsuo Handa
2020-06-26  6:39                                                                       ` Alexei Starovoitov
2020-06-26 12:51                                                               ` [PATCH 00/14] Make the user mode driver code a better citizen Eric W. Biederman
2020-06-26 12:53                                                                 ` [PATCH 01/14] umh: Capture the pid in umh_pipe_setup Eric W. Biederman
2020-06-26 12:53                                                                 ` [PATCH 02/14] umh: Move setting PF_UMH into umh_pipe_setup Eric W. Biederman
2020-06-26 12:54                                                                 ` [PATCH 03/14] umh: Rename the user mode driver helpers for clarity Eric W. Biederman
2020-06-26 12:54                                                                 ` [PATCH 04/14] umh: Remove call_usermodehelper_setup_file Eric W. Biederman
2020-06-26 12:55                                                                 ` [PATCH 05/14] umh: Separate the user mode driver and the user mode helper support Eric W. Biederman
2020-06-26 16:22                                                                   ` Tetsuo Handa
2020-06-26 16:45                                                                     ` Eric W. Biederman
2020-06-27  1:26                                                                       ` Tetsuo Handa
2020-06-27  4:21                                                                         ` Eric W. Biederman
2020-06-27  4:36                                                                           ` Tetsuo Handa
2020-06-26 12:55                                                                 ` [PATCH 06/14] umd: For clarity rename umh_info umd_info Eric W. Biederman
2020-06-26 15:37                                                                   ` Kees Cook
2020-06-26 16:31                                                                     ` Eric W. Biederman
2020-06-26 12:56                                                                 ` [PATCH 07/14] umd: Rename umd_info.cmdline umd_info.driver_name Eric W. Biederman
2020-06-26 12:56                                                                 ` [PATCH 08/14] umd: Transform fork_usermode_blob into fork_usermode_driver Eric W. Biederman
2020-06-26 12:57                                                                 ` [PATCH 09/14] umh: Stop calling do_execve_file Eric W. Biederman
2020-06-26 12:57                                                                 ` [PATCH 10/14] exec: Remove do_execve_file Eric W. Biederman
2020-06-26 12:58                                                                 ` [PATCH 11/14] bpfilter: Move bpfilter_umh back into init data Eric W. Biederman
2020-06-26 12:58                                                                 ` [PATCH 12/14] umd: Track user space drivers with struct pid Eric W. Biederman
2020-06-26 12:59                                                                 ` [PATCH 13/14] bpfilter: Take advantage of the facilities of " Eric W. Biederman
2020-06-26 12:59                                                                 ` [PATCH 14/14] umd: Remove exit_umh Eric W. Biederman
2020-06-26 13:48                                                                 ` [PATCH 00/14] Make the user mode driver code a better citizen Eric W. Biederman
2020-06-29 19:55                                                                   ` [PATCH v2 00/15] " Eric W. Biederman
2020-06-29 19:56                                                                     ` [PATCH v2 01/15] umh: Capture the pid in umh_pipe_setup Eric W. Biederman
2020-06-29 19:57                                                                     ` [PATCH v2 02/15] umh: Move setting PF_UMH into umh_pipe_setup Eric W. Biederman
2020-06-29 19:57                                                                     ` [PATCH v2 03/15] umh: Rename the user mode driver helpers for clarity Eric W. Biederman
2020-06-29 19:59                                                                     ` [PATCH v2 04/15] umh: Remove call_usermodehelper_setup_file Eric W. Biederman
2020-06-29 20:00                                                                     ` [PATCH v2 05/15] umh: Separate the user mode driver and the user mode helper support Eric W. Biederman
2020-06-30 16:58                                                                       ` Linus Torvalds
2020-07-01 17:18                                                                         ` Eric W. Biederman
2020-07-01 17:42                                                                           ` Alexei Starovoitov
2020-06-29 20:01                                                                     ` [PATCH v2 06/15] umd: For clarity rename umh_info umd_info Eric W. Biederman
2020-06-29 20:02                                                                     ` [PATCH v2 07/15] umd: Rename umd_info.cmdline umd_info.driver_name Eric W. Biederman
2020-06-29 20:03                                                                     ` [PATCH v2 08/15] umd: Transform fork_usermode_blob into fork_usermode_driver Eric W. Biederman
2020-06-29 20:03                                                                     ` [PATCH v2 09/15] umh: Stop calling do_execve_file Eric W. Biederman
2020-06-29 20:04                                                                     ` [PATCH v2 10/15] exec: Remove do_execve_file Eric W. Biederman
2020-06-30  5:43                                                                       ` Christoph Hellwig
2020-06-30 12:14                                                                         ` Eric W. Biederman
2020-06-30 13:38                                                                           ` Christoph Hellwig
2020-06-30 14:28                                                                             ` Eric W. Biederman
2020-06-30 16:55                                                                               ` Alexei Starovoitov
2020-06-29 20:05                                                                     ` [PATCH v2 11/15] bpfilter: Move bpfilter_umh back into init data Eric W. Biederman
2020-06-29 20:06                                                                     ` [PATCH v2 12/15] umd: Track user space drivers with struct pid Eric W. Biederman
2020-06-29 20:06                                                                     ` [PATCH v2 13/15] bpfilter: Take advantage of the facilities of " Eric W. Biederman
2020-06-29 20:07                                                                     ` [PATCH v2 14/15] umd: Remove exit_umh Eric W. Biederman
2020-06-29 20:08                                                                     ` [PATCH v2 15/15] umd: Stop using split_argv Eric W. Biederman
2020-06-29 22:12                                                                     ` [PATCH v2 00/15] Make the user mode driver code a better citizen Alexei Starovoitov
2020-06-30  1:13                                                                       ` Eric W. Biederman
2020-06-30  6:16                                                                         ` Tetsuo Handa
2020-06-30 12:29                                                                       ` Eric W. Biederman
2020-06-30 13:21                                                                         ` Tetsuo Handa
2020-07-02 13:08                                                                           ` Eric W. Biederman
2020-07-02 13:40                                                                             ` Tetsuo Handa
2020-07-02 16:02                                                                               ` Eric W. Biederman
2020-07-03 13:19                                                                                 ` Tetsuo Handa
2020-07-03 22:25                                                                                   ` Eric W. Biederman
2020-07-04  6:57                                                                                     ` Tetsuo Handa
2020-07-08  4:46                                                                                       ` Eric W. Biederman
2020-06-30 16:52                                                                         ` Alexei Starovoitov
2020-07-01 17:12                                                                           ` Eric W. Biederman
2020-07-02 16:40                                                                     ` [PATCH v3 00/16] " Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 01/16] umh: Capture the pid in umh_pipe_setup Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 02/16] umh: Move setting PF_UMH into umh_pipe_setup Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 03/16] umh: Rename the user mode driver helpers for clarity Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 04/16] umh: Remove call_usermodehelper_setup_file Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 05/16] umh: Separate the user mode driver and the user mode helper support Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 06/16] umd: For clarity rename umh_info umd_info Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 07/16] umd: Rename umd_info.cmdline umd_info.driver_name Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 08/16] umd: Transform fork_usermode_blob into fork_usermode_driver Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 09/16] umh: Stop calling do_execve_file Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 10/16] exec: Remove do_execve_file Eric W. Biederman
2020-07-08  6:35                                                                         ` Luis Chamberlain
2020-07-08 12:41                                                                           ` Luis Chamberlain
2020-07-08 13:08                                                                             ` Eric W. Biederman
2020-07-08 13:32                                                                               ` Luis Chamberlain
2020-07-12 21:02                                                                         ` Pavel Machek
2020-07-02 16:41                                                                       ` [PATCH v3 11/16] bpfilter: Move bpfilter_umh back into init data Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 12/16] umd: Track user space drivers with struct pid Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 13/16] exit: Factor thread_group_exited out of pidfd_poll Eric W. Biederman
2020-07-03 20:30                                                                         ` Alexei Starovoitov
2020-07-03 21:37                                                                           ` Eric W. Biederman
2020-07-04  0:03                                                                             ` Alexei Starovoitov
2020-07-04 15:50                                                                             ` Christian Brauner
2020-07-07 17:09                                                                               ` Eric W. Biederman
2020-07-08  0:05                                                                                 ` Daniel Borkmann
2020-07-08  3:50                                                                                   ` Eric W. Biederman
2020-07-04 16:00                                                                         ` Christian Brauner
2020-07-02 16:41                                                                       ` [PATCH v3 14/16] bpfilter: Take advantage of the facilities of struct pid Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 15/16] umd: Remove exit_umh Eric W. Biederman
2020-07-02 16:41                                                                       ` [PATCH v3 16/16] umd: Stop using split_argv Eric W. Biederman
2020-07-02 23:51                                                                       ` [PATCH v3 00/16] Make the user mode driver code a better citizen Tetsuo Handa
2020-07-09 22:05                                                                       ` [merged][PATCH " Eric W. Biederman
2020-07-14 19:42                                                                         ` Alexei Starovoitov
2020-07-08  5:20                                                                     ` [PATCH v2 00/15] " Luis Chamberlain
2020-06-26 14:10                                                                 ` [PATCH 00/14] " Greg Kroah-Hartman
2020-06-26 16:40                                                                 ` Alexei Starovoitov
2020-06-26 17:17                                                                   ` Eric W. Biederman
2020-06-26 18:22                                                                     ` Alexei Starovoitov
2020-06-27 11:38                                                                 ` Tetsuo Handa
2020-06-27 12:59                                                                   ` Eric W. Biederman
2020-06-27 13:57                                                                     ` Tetsuo Handa
2020-06-28 19:44                                                                       ` Alexei Starovoitov
2020-06-29  2:20                                                                         ` Tetsuo Handa
2020-06-29 20:19                                                                           ` Eric W. Biederman
2020-06-30  6:28                                                                             ` Tetsuo Handa
2020-06-30 12:32                                                                               ` Eric W. Biederman
2020-06-30 16:48                                                                               ` Alexei Starovoitov
2020-06-30 21:54                                                                                 ` Tetsuo Handa
2020-06-30 21:57                                                                                   ` Alexei Starovoitov
2020-06-30 22:58                                                                                     ` Tetsuo Handa
2020-06-25 12:56                                                 ` [RFC][PATCH] net/bpfilter: Remove this broken and apparently unmantained Stephen Smalley
2020-06-25 13:25                                                   ` Greg Kroah-Hartman
2020-06-25 14:26                                                     ` Stephen Smalley
2020-06-25 14:36                                                       ` Stephen Smalley
2020-06-25 15:21                                                       ` Tetsuo Handa
2020-06-25 16:03                                                         ` Stephen Smalley
2020-06-25 16:06                                                         ` Casey Schaufler
2020-06-26 11:30                                               ` Eric W. Biederman
2020-06-07  5:58             ` Eric W. Biederman
2020-06-07 11:56               ` Eric W. Biederman
2020-06-08 16:35                 ` Alexei Starovoitov
2020-06-08 16:33               ` Alexei Starovoitov
2020-06-06 20:43       ` Matthew Wilcox
2020-06-07 15:51         ` Eric W. Biederman
2020-06-07  1:13       ` Tetsuo Handa

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