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Date:   Fri, 19 Mar 2021 11:45:14 -0700
From:   Kees Cook <keescook@chromium.org>
To:     =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@digikod.net>
Cc:     James Morris <jmorris@namei.org>, Jann Horn <jannh@google.com>,
        "Serge E . Hallyn" <serge@hallyn.com>,
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        Michael Kerrisk <mtk.manpages@gmail.com>,
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        Shuah Khan <shuah@kernel.org>,
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        linux-security-module@vger.kernel.org, x86@kernel.org,
        =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@linux.microsoft.com>
Subject: Re: [PATCH v30 03/12] landlock: Set up the security framework and
 manage credentials
Message-ID: <202103191140.7D1F10CBFD@keescook>
References: <20210316204252.427806-1-mic@digikod.net>
 <20210316204252.427806-4-mic@digikod.net>
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On Tue, Mar 16, 2021 at 09:42:43PM +0100, Micka?l Sala?n wrote:
>  config LSM
>  	string "Ordered list of enabled LSMs"
> -	default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
> -	default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
> -	default "lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
> -	default "lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
> -	default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
> +	default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
> +	default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
> +	default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
> +	default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
> +	default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
>  	help
>  	  A comma-separated list of LSMs, in initialization order.
>  	  Any LSMs left off this list will be ignored. This can be

There was some discussion long ago about landlock needing to be last
in the list because it was unprivileged. Is that no longer true? (And
what is the justification for its position in the list?)

> diff --git a/security/landlock/common.h b/security/landlock/common.h
> new file mode 100644
> index 000000000000..5dc0fe15707d
> --- /dev/null
> +++ b/security/landlock/common.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Landlock LSM - Common constants and helpers
> + *
> + * Copyright ? 2016-2020 Micka?l Sala?n <mic@digikod.net>
> + * Copyright ? 2018-2020 ANSSI
> + */
> +
> +#ifndef _SECURITY_LANDLOCK_COMMON_H
> +#define _SECURITY_LANDLOCK_COMMON_H
> +
> +#define LANDLOCK_NAME "landlock"
> +
> +#ifdef pr_fmt
> +#undef pr_fmt
> +#endif

When I see "#undef pr_fmt" I think there is a header ordering problem.

> [...]

Everything else looks like regular boilerplate for an LSM. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook