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From: Kees Cook <keescook@chromium.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	linux-hardening@vger.kernel.org, linux-kbuild@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Justin Forbes <jforbes@redhat.com>,
	Ondrej Mosnacek <omosnace@redhat.com>
Subject: Re: [PATCH RFC] gcc-plugins: Handle GCC version mismatch for OOT modules
Date: Tue, 26 Jan 2021 14:59:57 -0800	[thread overview]
Message-ID: <202101261459.C90E9F97D@keescook> (raw)
In-Reply-To: <20210126184316.hpcy6gqp5vsq6ckq@treble>

On Tue, Jan 26, 2021 at 12:43:16PM -0600, Josh Poimboeuf wrote:
> On Tue, Jan 26, 2021 at 09:56:10AM -0800, Kees Cook wrote:
> > On Mon, Jan 25, 2021 at 04:19:53PM -0600, Josh Poimboeuf wrote:
> > > On Mon, Jan 25, 2021 at 02:03:07PM -0800, Kees Cook wrote:
> > > > On Mon, Jan 25, 2021 at 02:42:10PM -0600, Josh Poimboeuf wrote:
> > > > > When a GCC version mismatch is detected, print a warning and disable the
> > > > > plugin.  The only exception is the RANDSTRUCT plugin which needs all
> > > > > code to see the same struct layouts.  In that case print an error.
> > > > 
> > > > I prefer this patch as-is: only randstruct needs a hard failure. The
> > > > others likely work (in fact, randstruct likely works too).
> > > 
> > > I'm curious about this last statement, why would randstruct likely work?
> > > 
> > > Even struct module has '__randomize_layout', wouldn't basic module init
> > > go splat?
> > 
> > No; the seed is part of the generate includes -- you'll get the same
> > layout with the same seed.
> 
> Right, but don't you need the plugin enabled to make use of that seed,
> so the structs get interpreted properly by the module?  Or am I
> completely misunderstanding how this plugin works?

Having the plugin enabled or not is part of the Kconfig ... you can't
build anything if you change Kconfig. I feel like I'm missing
something...

-- 
Kees Cook

  reply	other threads:[~2021-01-27 10:26 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 20:42 [PATCH RFC] gcc-plugins: Handle GCC version mismatch for OOT modules Josh Poimboeuf
2021-01-25 21:16 ` Masahiro Yamada
2021-01-25 21:27   ` Josh Poimboeuf
2021-01-25 21:44     ` Masahiro Yamada
2021-01-25 22:07       ` Josh Poimboeuf
2021-01-26  8:13         ` Greg KH
2021-01-26 12:44           ` Justin Forbes
2021-01-26 13:51             ` Greg KH
2021-01-26 14:51               ` Josh Poimboeuf
2021-01-26 15:00                 ` Greg KH
2021-01-26 15:15                 ` Peter Zijlstra
2021-01-26 15:46                   ` Josh Poimboeuf
2021-01-26 16:05                     ` Peter Zijlstra
2021-01-26 16:15                       ` Justin Forbes
2021-01-26 16:19                         ` Josh Poimboeuf
2021-01-26 17:06                           ` Greg KH
2021-01-26 17:47                             ` Justin Forbes
2021-01-26 16:22                       ` David Laight
2021-01-27 18:03             ` Christoph Hellwig
2021-01-26  8:12     ` Greg KH
2021-01-25 22:03 ` Kees Cook
2021-01-25 22:19   ` Josh Poimboeuf
2021-01-26 17:56     ` Kees Cook
2021-01-26 18:43       ` Josh Poimboeuf
2021-01-26 22:59         ` Kees Cook [this message]
2021-01-26 23:32           ` Josh Poimboeuf
2021-01-26  1:53   ` Masahiro Yamada
2021-01-26 12:16     ` David Laight
2021-01-27 18:02 ` Christoph Hellwig
2021-01-27 18:38   ` Josh Poimboeuf
2021-01-27 18:43     ` Christoph Hellwig
2021-01-27 18:51       ` Josh Poimboeuf
2021-01-27 22:09         ` David Laight
2021-01-28 14:29         ` Christoph Hellwig
2021-01-28 15:45           ` Josh Poimboeuf
2021-03-02 23:26 ` Josh Poimboeuf
2021-03-03 18:49   ` Masahiro Yamada
2021-03-03 19:15     ` Josh Poimboeuf
2021-03-03 19:25       ` Linus Torvalds
2021-03-03 19:38         ` Josh Poimboeuf
2021-03-03 19:57           ` Linus Torvalds
2021-03-03 20:24             ` Josh Poimboeuf
2021-03-03 20:31               ` Josh Poimboeuf
2021-03-03 20:56               ` Linus Torvalds
2021-03-03 21:45                 ` Josh Poimboeuf
2021-03-04 12:27                   ` Masahiro Yamada
2021-03-04 15:08                     ` Josh Poimboeuf
2021-03-04 15:35                       ` Masahiro Yamada
2021-03-04 19:12                         ` Linus Torvalds
2021-03-05  2:41                           ` Josh Poimboeuf
2021-03-05  2:49                             ` Linus Torvalds
2021-03-05 16:03                             ` Masahiro Yamada
2021-03-05 19:18                               ` Josh Poimboeuf
2021-03-08  9:39                                 ` David Laight
2021-03-05 15:31                           ` Masahiro Yamada
2021-03-03 21:52             ` Kees Cook
2021-03-04 12:26       ` Masahiro Yamada

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