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From: Kees Cook <keescook@chromium.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, will@kernel.org,
	mark.rutland@arm.com, catalin.marinas@arm.com, maz@kernel.org,
	Sami Tolvanen <samitolvanen@google.com>,
	Fangrui Song <maskray@google.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Dan Li <ashimida@linux.alibaba.com>
Subject: Re: [RFC PATCH v2 3/3] arm64: implement dynamic shadow call stack for Clang
Date: Thu, 5 May 2022 17:00:05 -0700	[thread overview]
Message-ID: <202205051657.A83407E@keescook> (raw)
In-Reply-To: <20220505161011.1801596-4-ardb@kernel.org>

On Thu, May 05, 2022 at 06:10:11PM +0200, Ard Biesheuvel wrote:
> [...]
> +	/*
> +	 * We only enable the shadow call stack dynamically if we are running
> +	 * on a system that does not implement PAC or BTI. PAC and SCS roughly
> +	 * provide the same level of protection, and BTI relies on the PACIASP
> +	 * instructions serving as landing pads, preventing us from patching
> +	 * those instructions into something else.
> +	 */

If BTI relies on PAC, then we only need to check for PAC, yes? I.e.
there isn't going to be a device with BTI but without PAC.

-- 
Kees Cook

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  parent reply	other threads:[~2022-05-06  0:01 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-05 16:10 [RFC PATCH v2 0/3] arm64: dynamic shadow call stack support Ard Biesheuvel
2022-05-05 16:10 ` [RFC PATCH v2 1/3] arm64: unwind: add asynchronous unwind tables to kernel and modules Ard Biesheuvel
2022-05-05 20:19   ` Nick Desaulniers
2022-05-06  7:07     ` Ard Biesheuvel
2022-05-05 16:10 ` [RFC PATCH v2 2/3] scs: add support for dynamic shadow call stacks Ard Biesheuvel
2022-05-05 21:14   ` Nick Desaulniers
2022-05-06  0:00   ` Kees Cook
2022-05-05 16:10 ` [RFC PATCH v2 3/3] arm64: implement dynamic shadow call stack for Clang Ard Biesheuvel
2022-05-05 21:01   ` Nick Desaulniers
2022-05-18  1:53     ` Sami Tolvanen
2022-05-06  0:00   ` Kees Cook [this message]
2022-05-06  6:59     ` Ard Biesheuvel

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