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From: Greg KH <gregkh@linuxfoundation.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"Eric W. Biederman" <ebiederm@xmission.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: Mon, 8 Jun 2020 18:40:45 +0200
Message-ID: <20200608164045.GC425601@kroah.com> (raw)
In-Reply-To: <20200608162027.iyaqtnhrjtp3vos5@ast-mbp.dhcp.thefacebook.com>

On Mon, Jun 08, 2020 at 09:20:27AM -0700, Alexei Starovoitov wrote:
> On Sat, Jun 06, 2020 at 07:19:56PM -0700, Linus Torvalds wrote:
> > 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?
> 
> Right. There is no room for large user space application like clang
> in vmlinux. The idea for umh was to stay small and self contained.
> Its advantage vs kernel module is to execute with user privs
> and use normal syscalls to drive kernel instead of export_symbol apis.
> 
> There are two things in this discussion. bpfilter that intercepting
> netfilter sockopt and elf file embedded into vmlinux that executes
> as user process.
> The pro/con of bpfilter approach is hard to argue now because
> bpfilter itself didn't materialize yet. I'm fine with removal of that part
> from the kernel, but I'm still arguing that 'embed elf into vmlinux'
> is necessary, useful and there is no alternative.
> There are builtin kernel modules. 'elf in vmlinux' is similar to that.
> The primary use case is bpf driven features like bpf_lsm.
> bpf_lsm needs to load many different bpf programs, create bpf maps, populate
> them, attach to lsm hooks to make the whole thing ready. That initialization of
> bpf_lsm is currently done after everything booted, but folks want it to be
> active much early. Like other LSMs.
> Take android for example. It can certify vmlinux, but not boot fs image.

Huh?  dm-verity does this for the whole "boot fs partition" already,
right?  Or one of the "dm-" modules...

> vmlinux needs to apply security policy via bpf_lsm during the boot.
> In such case 'embedded elf in vmlinux' would start early, do its thing
> via bpf syscall and exit. Unlike bpfilter approach it won't stay running.
> Its job is to setup all bpf things and quit.
> Theoretically we can do it as proper kernel module, but then it would mean huge
> refactoring of all bpf syscall commands to be accessible from the kernel module.
> It's simpler to embed elf into vmlinux and run it as user process doing normal
> syscalls. I can imagine that in other cases this elf executable would keep
> running after setup.
> It doesn't have to be bpf related. Folks thought they can do usb drivers
> running in user space and ready at boot. 'elf in vmlinux' would work as well.

I still want to work on the "usb drivers in userspace" like this, it's
on my TODO for this year.  But don't let that "sometime in the future
wish" keep this code around if no one is currently using it.

thanks,

greg k-h

  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
2020-06-08 16:20               ` Alexei Starovoitov
2020-06-08 16:40                 ` Greg KH [this message]
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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