linux-kernel - Re: [PATCH 1/2] Compiler Attributes: Add _

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <202402050818.B11CFAD2B@keescook>
Date: Mon, 5 Feb 2024 08:21:47 -0800
From: Kees Cook <keescook@...omium.org>
To: Heiko Carstens <hca@...ux.ibm.com>
Cc: Nathan Chancellor <nathan@...nel.org>,
	Nick Desaulniers <ndesaulniers@...gle.com>,
	linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
	Vasily Gorbik <gor@...ux.ibm.com>,
	Alexander Gordeev <agordeev@...ux.ibm.com>
Subject: Re: [PATCH 1/2] Compiler Attributes: Add __uninitialized macro

On Mon, Feb 05, 2024 at 04:48:43PM +0100, Heiko Carstens wrote:
> With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled the kernel will
> be compiled with -ftrivial-auto-var-init=<...> which causes initialization
> of stack variables at function entry time.
> 
> In order to avoid the performance impact that comes with this users can use
> the "uninitialized" attribute to prevent such initialization.
> 
> Therefore provide the __uninitialized macro which can be used for cases
> where INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO is enabled, but only
> selected variables should not be initialized.
> 
> Signed-off-by: Heiko Carstens <hca@...ux.ibm.com>

Thanks! We had something similar a while back with syscall entry:
efa90c11f62e ("stack: Constrain and fix stack offset randomization with Clang builds")

Acked-by: Kees Cook <keescook@...omium.org>

-- 
Kees Cook