Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v21 07/12] landlock: Support filesystem access-control
From:   =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mic@digikod.net>
To:     James Morris <jmorris@namei.org>
Cc:     linux-kernel@vger.kernel.org,
        "Serge E . Hallyn" <serge@hallyn.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Richard Weinberger <richard@nod.at>,
        Andy Lutomirski <luto@amacapital.net>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Casey Schaufler <casey@schaufler-ca.com>,
        Jann Horn <jannh@google.com>, Jeff Dike <jdike@addtoit.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Shuah Khan <shuah@kernel.org>,
        Vincent Dagonneau <vincent.dagonneau@ssi.gouv.fr>,
        kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-security-module@vger.kernel.org, x86@kernel.org,
        =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mic@linux.microsoft.com>
References: <20201008153103.1155388-1-mic@digikod.net>
 <20201008153103.1155388-8-mic@digikod.net>
 <alpine.LRH.2.21.2010150504360.26012@namei.org>
 <77ea263c-4200-eb74-24b2-9a8155aff9b5@digikod.net>
Message-ID: <b311a2a6-5290-5c50-3a9c-4d5b54b6b406@digikod.net>
Date:   Wed, 14 Oct 2020 21:13:42 +0200
User-Agent: 
MIME-Version: 1.0
In-Reply-To: <77ea263c-4200-eb74-24b2-9a8155aff9b5@digikod.net>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk


On 14/10/2020 20:52, Mickaël Salaün wrote:
> 
> On 14/10/2020 20:07, James Morris wrote:
>> On Thu, 8 Oct 2020, Mickaël Salaün wrote:
>>
>>> +config ARCH_EPHEMERAL_STATES
>>> +	def_bool n
>>> +	help
>>> +	  An arch should select this symbol if it does not keep an internal kernel
>>> +	  state for kernel objects such as inodes, but instead relies on something
>>> +	  else (e.g. the host kernel for an UML kernel).
>>> +
>>
>> This is used to disable Landlock for UML, correct?
> 
> Yes
> 
>> I wonder if it could be 
>> more specific: "ephemeral states" is a very broad term.
>>
>> How about something like ARCH_OWN_INODES ?
> 
> Sounds good. We may need add new ones (e.g. for network socket, UID,
> etc.) in the future though.
> 

Because UML is the exception here, it would be more convenient to keep
the inverted semantic. What about ARCH_NO_OWN_INODES or
ARCH_EPHEMERAL_INODES?