From: David Miller <davem@davemloft.net>
To: luto@kernel.org
Cc: alexei.starovoitov@gmail.com, keescook@chromium.org,
ast@kernel.org, tixxdz@gmail.com, viro@zeniv.linux.org.uk,
daniel@iogearbox.net, torvalds@linux-foundation.org,
gregkh@linuxfoundation.org, mcgrof@kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, linux-api@vger.kernel.org
Subject: Re: [PATCH net-next] modules: allow modprobe load regular elf binaries
Date: Thu, 08 Mar 2018 21:31:53 -0500 (EST) [thread overview]
Message-ID: <20180308.213153.2003279953084099668.davem@davemloft.net> (raw)
In-Reply-To: <CALCETrV8nPo=_rsSzy3Dt+y09mNgRi2+aYRk0Pj45j6BLRXgAA@mail.gmail.com>
From: Andy Lutomirski <luto@kernel.org>
Date: Fri, 9 Mar 2018 02:12:24 +0000
> First, compile your user code and emit a staitc binary. Use objdump
> fiddling or a trivial .S file to make that static binary into a
> variable. Then write a tiny shim module like this:
>
> extern unsigned char __begin_user_code[], __end_user_code[];
>
> int __init init_shim_module(void)
> {
> return call_umh_blob(__begin_user_code, __end_user_code - __begin_user_code);
> }
>
> By itself, this is clearly a worse solution than yours, but it has two
> benefits, one small and two big. The small benefit is that it is
> completely invisible to userspace: the .ko file is a bona fide module.
Anything you try to do which makes these binaries "special" is a huge
negative.
> The big benefits are:
I don't see those things as benefits at all, and Alexei's scheme can
easily be made to work in your benefit #1 case too.
It's a user binary. It's shipped with the kernel and it's signed.
If we can't trust that, we can't trust much else.
And this whole container argument.. It's a mirage.
Kernel modules are 1000 times worse, since they can access any
container and any namespace they want.
next prev parent reply other threads:[~2018-03-09 2:31 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-06 1:34 [PATCH net-next] modules: allow modprobe load regular elf binaries Alexei Starovoitov
2018-03-06 2:13 ` Randy Dunlap
2018-03-06 3:02 ` Alexei Starovoitov
2018-03-06 11:05 ` Greg KH
2018-03-07 1:07 ` Alexei Starovoitov
2018-03-07 3:24 ` Greg KH
2018-03-06 19:12 ` Linus Torvalds
2018-03-06 23:42 ` Chris Mason
2018-05-02 9:12 ` Jesper Dangaard Brouer
2018-03-06 20:01 ` Andy Lutomirski
2018-03-06 20:26 ` Linus Torvalds
2018-03-07 17:22 ` David Miller
2018-03-08 1:23 ` Luis R. Rodriguez
2018-03-08 23:07 ` Alexei Starovoitov
2018-03-09 1:58 ` Luis R. Rodriguez
2018-03-09 0:24 ` Kees Cook
2018-03-09 0:57 ` Alexei Starovoitov
2018-03-09 1:04 ` Andy Lutomirski
2018-03-09 1:25 ` Alexei Starovoitov
2018-03-09 1:24 ` Kees Cook
2018-03-09 0:59 ` Andy Lutomirski
2018-03-09 1:20 ` Alexei Starovoitov
2018-03-09 2:12 ` Andy Lutomirski
2018-03-09 2:31 ` David Miller [this message]
2018-03-09 3:10 ` Andy Lutomirski
2018-03-09 3:27 ` Alexei Starovoitov
2018-03-09 1:38 ` Linus Torvalds
2018-03-09 1:44 ` Kees Cook
2018-03-09 3:06 ` Linus Torvalds
2018-03-09 3:17 ` Linus Torvalds
2018-03-09 3:54 ` Andy Lutomirski
2018-03-09 5:08 ` Alexei Starovoitov
2018-03-09 15:16 ` Andy Lutomirski
2018-03-09 15:39 ` Alexei Starovoitov
2018-03-09 16:24 ` Andy Lutomirski
2018-03-09 17:32 ` Alexei Starovoitov
2018-03-09 18:15 ` Greg KH
2018-03-09 18:23 ` Andy Lutomirski
2018-03-09 18:29 ` Greg KH
2018-03-09 18:50 ` Alexei Starovoitov
2018-03-09 18:55 ` David Miller
2018-03-09 19:37 ` Andy Lutomirski
2018-03-10 1:43 ` Alexei Starovoitov
2018-03-11 2:17 ` Andy Lutomirski
2018-03-09 18:17 ` Linus Torvalds
2018-03-09 18:35 ` David Miller
2018-03-09 18:43 ` Kees Cook
2018-03-09 18:50 ` Linus Torvalds
2018-03-09 18:54 ` Kees Cook
2018-03-09 18:58 ` Alexei Starovoitov
2018-03-12 12:02 ` Edward Cree
2018-03-12 17:49 ` Alexei Starovoitov
2018-03-09 18:48 ` Andy Lutomirski
2018-03-09 18:53 ` Linus Torvalds
2018-03-09 18:57 ` David Miller
2018-03-09 19:12 ` Linus Torvalds
2018-03-09 19:38 ` Linus Torvalds
2018-03-09 19:45 ` Andy Lutomirski
2018-03-10 2:34 ` Alexei Starovoitov
2018-03-10 14:08 ` Luis R. Rodriguez
2018-03-10 15:16 ` Luis R. Rodriguez
2018-03-10 15:34 ` Luis R. Rodriguez
2018-03-12 17:22 ` Alexei Starovoitov
2018-03-13 8:48 ` Greg Kroah-Hartman
2018-03-22 20:54 ` Luis R. Rodriguez
2018-03-22 22:15 ` Andy Lutomirski
2018-03-22 22:21 ` Alexei Starovoitov
2018-03-23 2:47 ` Luis R. Rodriguez
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