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From: Kees Cook <keescook@chromium.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
	Sami Tolvanen <samitolvanen@google.com>
Subject: Re: [PATCH] arm64: efi: Make runtime service wrapper more robust
Date: Thu, 1 Dec 2022 15:45:16 -0800	[thread overview]
Message-ID: <202212011544.2AA7C8A5@keescook> (raw)
In-Reply-To: <20221128094939.801232-1-ardb@kernel.org>

On Mon, Nov 28, 2022 at 10:49:39AM +0100, Ard Biesheuvel wrote:
> Prevent abuse of the runtime service wrapper code by avoiding restoring
> the shadow call stack pointer from the ordinary stack, or the stack
> pointer itself from a GPR. Also, given that the exception recovery
> routine is never called in an ordinary way, it doesn't need BTI landing
> pads so it can be SYM_CODE rather than SYM_FUNC.

Does this mean x18 is now being spilled to the stack? (Do we already
spill it in other places?)

-- 
Kees Cook

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  reply	other threads:[~2022-12-01 23:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-28  9:49 [PATCH] arm64: efi: Make runtime service wrapper more robust Ard Biesheuvel
2022-12-01 23:45 ` Kees Cook [this message]
2022-12-01 23:47   ` Ard Biesheuvel
2022-12-01 23:52     ` Ard Biesheuvel

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