linux-kernel - Re: [PATCH v3 1/7] sysfs: attribute_group: allow registration of const attribute

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: <2025081957-refueling-anteater-4720@gregkh>
Date: Tue, 19 Aug 2025 13:22:55 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Thomas Weißschuh <linux@...ssschuh.net>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
	Danilo Krummrich <dakr@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/7] sysfs: attribute_group: allow registration of
 const attribute

On Mon, Aug 11, 2025 at 11:14:27AM +0200, Thomas Weißschuh wrote:
> To be able to constify instances of struct attribute it has to be
> possible to add them to struct attribute_group.
> The current type of the attrs member however is not compatible with that.
> Introduce a union that allows registration of both const and non-const
> attributes to enable a piecewise transition.
> As both union member types are compatible no logic needs to be adapted.
> 
> Technically it is now possible register a const struct
> attribute and receive it as mutable pointer in the callbacks.
> This is a soundness issue.
> But this same soundness issue already exists today in
> sysfs_create_file().
> Also the struct definition and callback implementation are always
> closely linked and are meant to be moved to const in lockstep.
> 
> Similar to commit 906c508afdca ("sysfs: attribute_group: allow registration of const bin_attribute")
> 
> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> ---
>  include/linux/sysfs.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index f418aae4f1134f8126783d9e8eb575ba4278e927..a47092e837d9eb014894d1f7e49f0fd0f9a2e350 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -105,7 +105,10 @@ struct attribute_group {
>  	size_t			(*bin_size)(struct kobject *,
>  					    const struct bin_attribute *,
>  					    int);
> -	struct attribute	**attrs;
> +	union {
> +		struct attribute	**attrs;
> +		const struct attribute	*const *attrs_new;

I know you will drop the "_new" prefix after a while, but "new" is
relative, and not very descriptive.  How about "_const"?

> +	};
>  	union {
>  		const struct bin_attribute	*const *bin_attrs;
>  		const struct bin_attribute	*const *bin_attrs_new;

There is no bin_attrs_new anymore.  Finally.  sorry about that...

greg k-h