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From: Kees Cook <keescook@chromium.org>
To: Joao Moreira <joao@overdrivepizza.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org, hjl.tools@gmail.com, jpoimboe@redhat.com,
	andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org,
	ndesaulniers@google.com, samitolvanen@google.com,
	llvm@lists.linux.dev
Subject: Re: [RFC][PATCH 6/6] objtool: Add IBT validation / fixups
Date: Tue, 8 Feb 2022 20:05:46 -0800	[thread overview]
Message-ID: <202202082003.FA77867@keescook> (raw)
In-Reply-To: <ad6c2633f39e39583bc5c5eaf7ccbe52@overdrivepizza.com>

On Tue, Feb 08, 2022 at 06:21:16PM -0800, Joao Moreira wrote:
> > > Note: This feature was already submitted for upstreaming with the
> > > llvm-project: https://reviews.llvm.org/D116070
> > 
> > Ah nice; I see this has been committed now.
> 
> Yes, but then some front-end changes also required this fix
> https://reviews.llvm.org/D118052, which is currently under review (posting
> this here in case someone is trying this out).
> 
> > 
> > Given that IBT will need to work with both Clang and gcc, I suspect the
> > objtool approach will still end up needing to do all the verification.
> > 
> > (And as you say, it has limited visibility into assembly.)
> 
> Agreed that at this point objtool provides more coverage. Yet, besides being
> an attempt to relief objtool and improve a bit the compiler support as
> mentioned in the series cover letter, it is still nice to reduce the
> left-over nops and fixups which end-up scattered all around.
> 
> FWIIW, https://reviews.llvm.org/D118438 and https://reviews.llvm.org/D118355
> are also being cooked. Comments and ideas for new approaches or improvements
> in the compiler support for this are very welcome :)

Ah, excellent, thanks for the pointers. There's also this in the works:
https://reviews.llvm.org/D119296 (a new CFI mode, designed to play nice
to objtool, IBT, etc.)

-- 
Kees Cook

  reply	other threads:[~2022-02-09  4:05 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-22 17:03 [RFC][PATCH 0/6] x86: Kernel IBT beginnings Peter Zijlstra
2021-11-22 17:03 ` [RFC][PATCH 1/6] x86: Annotate _THIS_IP_ Peter Zijlstra
2021-11-23 13:53   ` Mark Rutland
2021-11-23 14:14     ` Peter Zijlstra
2021-11-24 18:18       ` Josh Poimboeuf
2021-11-22 17:03 ` [RFC][PATCH 2/6] x86: Base IBT bits Peter Zijlstra
2022-02-08 23:32   ` Kees Cook
2021-11-22 17:03 ` [RFC][PATCH 3/6] x86: Add ENDBR to IRET-to-Self Peter Zijlstra
2021-11-22 18:09   ` Peter Zijlstra
2022-02-08 23:33     ` Kees Cook
2021-11-22 17:03 ` [RFC][PATCH 4/6] objtool: Read the _THIS_IP_ hints Peter Zijlstra
2021-11-22 17:03 ` [RFC][PATCH 5/6] x86: Sprinkle ENDBR dust Peter Zijlstra
2021-11-23 14:00   ` Mark Rutland
2021-11-23 14:21     ` Peter Zijlstra
2022-02-08 23:38     ` Kees Cook
2021-11-22 17:03 ` [RFC][PATCH 6/6] objtool: Add IBT validation / fixups Peter Zijlstra
2021-11-24 19:30   ` Josh Poimboeuf
2022-02-08 23:43     ` Kees Cook
2022-02-09  5:09       ` Josh Poimboeuf
2022-02-09 11:41       ` Peter Zijlstra
2022-02-09 11:45         ` Peter Zijlstra
2021-12-24  2:05   ` joao
2022-02-08 23:42     ` Kees Cook
2022-02-09  2:21       ` Joao Moreira
2022-02-09  4:05         ` Kees Cook [this message]
2022-02-09  5:18           ` Joao Moreira
2022-02-11 13:38             ` Peter Zijlstra
2022-02-14 21:38               ` Sami Tolvanen
2022-02-14 22:25                 ` Peter Zijlstra
2022-02-15 16:56                   ` Sami Tolvanen
2022-02-15 20:03                     ` Kees Cook
2022-02-15 21:05                       ` Peter Zijlstra
2022-02-15 23:05                         ` Kees Cook
2022-02-15 23:38                           ` Joao Moreira
2022-02-16 12:24                         ` Peter Zijlstra
2022-02-15 20:53                     ` Peter Zijlstra
2022-02-15 22:45               ` Joao Moreira
2022-02-16  0:57               ` Andrew Cooper
2022-03-02  3:06               ` Peter Collingbourne
2022-03-02  3:32                 ` Joao Moreira
2022-06-08 17:53                 ` Fāng-ruì Sòng
2022-06-09  0:05                   ` Sami Tolvanen
2021-11-23  7:58 ` [RFC][PATCH 0/6] x86: Kernel IBT beginnings Christoph Hellwig
2021-11-23  9:02   ` Peter Zijlstra
2022-02-08 23:48 ` Kees Cook
2022-02-09  0:09 ` Nick Desaulniers

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