Re: [PATCH v1 2/8] LSM: Add an LSM identifier for external use

From: Greg KH <gregkh@linuxfoundation.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: casey.schaufler@intel.com, paul@paul-moore.com,
	linux-security-module@vger.kernel.org, jmorris@namei.org,
	keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp,
	stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org,
	linux-api@vger.kernel.org, mic@digikod.net
Subject: Re: [PATCH v1 2/8] LSM: Add an LSM identifier for external use
Date: Wed, 26 Oct 2022 07:58:17 +0200	[thread overview]
Message-ID: <Y1jMeWl0oV4/2zyE@kroah.com> (raw)
In-Reply-To: <20221025184519.13231-3-casey@schaufler-ca.com>

On Tue, Oct 25, 2022 at 11:45:13AM -0700, Casey Schaufler wrote:
> Add an integer member "id" to the struct lsm_id. This value is
> a unique identifier associated with each security module. The
> values are defined in a new UAPI header file. Each existing LSM
> has been updated to include it's LSMID in the lsm_id.
> 
> The LSM ID values are sequential, with the oldest module
> LSM_ID_CAPABILITY being the lowest value and the existing
> modules numbered in the order they were included in the
> main line kernel. The first 32 values (0 - 31) are reserved
> for some as yet unknown but important use.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
>  include/linux/lsm_hooks.h    |  1 +
>  include/uapi/linux/lsm.h     | 32 ++++++++++++++++++++++++++++++++
>  security/apparmor/lsm.c      |  2 ++
>  security/bpf/hooks.c         |  2 ++
>  security/commoncap.c         |  2 ++
>  security/landlock/setup.c    |  2 ++
>  security/loadpin/loadpin.c   |  2 ++
>  security/lockdown/lockdown.c |  2 ++
>  security/safesetid/lsm.c     |  2 ++
>  security/selinux/hooks.c     |  2 ++
>  security/smack/smack_lsm.c   |  2 ++
>  security/tomoyo/tomoyo.c     |  2 ++
>  security/yama/yama_lsm.c     |  2 ++
>  13 files changed, 55 insertions(+)
>  create mode 100644 include/uapi/linux/lsm.h
> 
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index e383e468f742..dd4b4d95a172 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1607,6 +1607,7 @@ struct security_hook_heads {
>   */
>  struct lsm_id {
>  	const char	*lsm;		/* Name of the LSM */
> +	int		id;		/* LSM ID */

Again, kerneldoc.

And if this crosses the user/kernel boundry, please make it __u64.  Or
__s32?  Something explicit please.

>  };
>  
>  /*
> diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h
> new file mode 100644
> index 000000000000..d5bcbb9375df
> --- /dev/null
> +++ b/include/uapi/linux/lsm.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Linus Security Modules (LSM) - User space API

s/Linus/Linux/.

> + *
> + * Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com>
> + * Copyright (C) Intel Corporation

No date for Intel?

> + */
> +
> +#ifndef _UAPI_LINUX_LSM_H
> +#define _UAPI_LINUX_LSM_H
> +
> +/*
> + * ID values to identify security modules.
> + * A system may use more than one security module.
> + *
> + * LSM_ID_XXX values 0 - 31 are reserved for future use

Reserved for what?  Why?

thanks,

greg k-h