linux-hardening - Re: [PATCH 5/5] kcfi: Rename CONFIG_CFI_CLANG to CONFIG

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: <25B398C8-4D9A-46C6-AED9-9DA2805DF9D7@kernel.org>
Date: Thu, 28 Aug 2025 16:32:16 -0400
From: Kees Cook <kees@...nel.org>
To: Nathan Chancellor <nathan@...nel.org>,
 Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
CC: Randy Dunlap <rdunlap@...radead.org>, Kees Cook <kees@...flux.net>,
 Peter Zijlstra <peterz@...radead.org>,
 Sami Tolvanen <samitolvanen@...gle.com>,
 Linus Walleij <linus.walleij@...aro.org>,
 Mark Rutland <mark.rutland@....com>, Puranjay Mohan <puranjay@...nel.org>,
 David Woodhouse <dwmw2@...radead.org>, Jonathan Corbet <corbet@....net>,
 x86@...nel.org, linux-doc@...r.kernel.org, linux-kbuild@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-riscv@...ts.infradead.org,
 llvm@...ts.linux.dev, linux-hardening@...r.kernel.org
Subject: Re: [PATCH 5/5] kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI



On August 28, 2025 4:19:15 PM EDT, Nathan Chancellor <nathan@...nel.org> wrote:
>On Thu, Aug 28, 2025 at 02:11:51PM +0200, Miguel Ojeda wrote:
>> On Wed, Aug 27, 2025 at 9:38 PM Nathan Chancellor <nathan@...nel.org> wrote:
>> > Another idea I had to avoid this is introducing CONFIG_CFI_GCC as a user
>> > selectable symbol and making CONFIG_CFI the hidden symbol that both
>> > compiler symbols select. After a couple of releases (or maybe the next
>> > LTS), both CONFIG_CFI_CLANG and CONFIG_CFI_GCC could be eliminated with
>> > CONFIG_CFI becoming user selectable, which would keep things working
>> > since CONFIG_CFI=y will be present in the previous configuration.
>> 
>> If we are OK with something like this (i.e. waiting a few releases),
>> then isn't it simpler the `def_bool` approach I mentioned? i.e. it
>> means one less symbol and one less rename later, right?
>
>Ah yes, I reread your suggestion and that would probably be the best
>course of action, as it does avoid the extra symbol (although I am not
>sure what you mean by one less rename?). As I understand it:
>
>  config CFI_CLANG
>      bool "Use Kernel Control Flow Integrity (kCFI)"
>      depends on ARCH_SUPPORTS_CFI
>      depends on $(cc-option,-fsanitize=kcfi)
>      help
>        <generic help text>
>
>  config CFI
>      def_bool CFI_CLANG

Oh! Keep CFI_CLANG the visible option? Will the later rename work right? I'll give it a try.

-Kees

-- 
Kees Cook