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From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com,
	jpoimboe@redhat.com, andrew.cooper3@citrix.com,
	linux-kernel@vger.kernel.org, ndesaulniers@google.com,
	keescook@chromium.org, samitolvanen@google.com
Subject: Re: [RFC][PATCH 0/6] x86: Kernel IBT beginnings
Date: Tue, 23 Nov 2021 10:02:53 +0100	[thread overview]
Message-ID: <YZyuPffZU5bOjzBQ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YZyfM/gUoPV6p+30@infradead.org>

On Mon, Nov 22, 2021 at 11:58:43PM -0800, Christoph Hellwig wrote:
> What is "IBT"?

Fair enough; it's Indirect Branch Tracking, it's a hardware feature that
ensures any indirect JMP/CALL can only ever land on an ENDBR
instruction. It's a form of Control Flow Integrity, albeit a weak one.
(FineIBT is a software improvement that combines this with a hash value
to further narrow the allowed branches. People are working on that, but
basics first etc..)

More practical, by stripping ENDBR instruction from functions that are
never called indirectly, we insta kill the tried and true method of:

	func = kallsym_lookup_name("unexported_function");
	(*func)(args);

favoured by pretty much every out of tree piece-of-cra^Wmodule.

  reply	other threads:[~2021-11-23  9:03 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-22 17:03 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
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 [this message]
2022-02-08 23:48 ` Kees Cook
2022-02-09  0:09 ` Nick Desaulniers

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