linux-kernel - Re: [PATCH 1/1] hardening: simplify CONFIG_CC_HAS_COUNTED

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] [day] [month] [year] [list]

Message-ID: <20250430231306.GA3715926@ax162>
Date: Wed, 30 Apr 2025 16:13:06 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Jan Hendrik Farr <kernel@...rr.cc>
Cc: Kees Cook <kees@...nel.org>, Miguel Ojeda <ojeda@...nel.org>,
	Bill Wendling <morbo@...gle.com>, thorsten.blum@...lux.com,
	"Gustavo A . R . Silva" <gustavoars@...nel.org>,
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
	Justin Stitt <justinstitt@...gle.com>,
	linux-hardening@...r.kernel.org, llvm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] hardening: simplify CONFIG_CC_HAS_COUNTED_BY

On Wed, Apr 30, 2025 at 08:42:31PM +0200, Jan Hendrik Farr wrote:
> Simplifies CONFIG_CC_HAS_COUNTED_BY by removing the build test and
> relying solely on gcc/clang version numbering (GCC_VERSION >= 150100 and
> CLANG_VERSION >= 190103).
> 
> The build test was used to allow unreleased gcc 15.0 builds to use the
> __counted_by attribute. Now that gcc 15.1.0 has been released, this is
> not needed anymore. Note: This will disable __counted_by on unreleased
> gcc 15.0 builds.
> 
> clang version support for __counted_by remains unchanged.
> 
> Link: https://lore.kernel.org/all/Zw8iawAF5W2uzGuh@archlinux/T/#m204c09f63c076586a02d194b87dffc7e81b8de7b
> Link: https://lore.kernel.org/r/20241029140036.577804-2-kernel@jfarr.cc
> Suggested-by: Nathan Chancellor <nathan@...nel.org>
> Signed-off-by: Jan Hendrik Farr <kernel@...rr.cc>

Reviewed-by: Nathan Chancellor <nathan@...nel.org>

> ---
>  init/Kconfig | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index 63f5974b9fa6..017fde21d0ba 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -121,13 +121,14 @@ config CC_HAS_NO_PROFILE_FN_ATTR
>  	def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
>  
>  config CC_HAS_COUNTED_BY
> -	# TODO: when gcc 15 is released remove the build test and add
> -	# a gcc version check
> -	def_bool $(success,echo 'struct flex { int count; int array[] __attribute__((__counted_by__(count))); };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)
> +	bool
>  	# clang needs to be at least 19.1.3 to avoid __bdos miscalculations
>  	# https://github.com/llvm/llvm-project/pull/110497
>  	# https://github.com/llvm/llvm-project/pull/112636
> -	depends on !(CC_IS_CLANG && CLANG_VERSION < 190103)
> +	default y if CC_IS_CLANG && CLANG_VERSION >= 190103
> +	# supported since gcc 15.1.0
> +	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896
> +	default y if CC_IS_GCC && GCC_VERSION >= 150100
>  
>  config CC_HAS_MULTIDIMENSIONAL_NONSTRING
>  	def_bool $(success,echo 'char tag[][4] __attribute__((__nonstring__)) = { };' | $(CC) $(CLANG_FLAGS) -x c - -c -o /dev/null -Werror)
> -- 
> 2.49.0
>