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Subject: Re: [PATCH v17 05/10] fs,landlock: Support filesystem access-control
To:     Casey Schaufler <casey@schaufler-ca.com>,
        James Morris <jmorris@namei.org>
Cc:     linux-kernel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@amacapital.net>,
        Arnd Bergmann <arnd@arndb.de>, Jann Horn <jannh@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mickael.salaun@ssi.gouv.fr>,
        "Serge E . Hallyn" <serge@hallyn.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
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 <20200511192156.1618284-6-mic@digikod.net>
 <alpine.LRH.2.21.2005141335280.30052@namei.org>
 <c159d845-6108-4b67-6527-405589fa5382@digikod.net>
 <bcfa8f74-5bc9-b363-5372-b254ba2e88a7@schaufler-ca.com>
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Date:   Thu, 14 May 2020 20:46:08 +0200
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On 14/05/2020 17:58, Casey Schaufler wrote:
> On 5/14/2020 3:39 AM, Mickaël Salaün wrote:
>> On 14/05/2020 05:37, James Morris wrote:
>>> On Mon, 11 May 2020, Mickaël Salaün wrote:
>>>
>>>
>>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>>> index 45cc10cdf6dd..2276642f8e05 100644
>>>> --- a/include/linux/fs.h
>>>> +++ b/include/linux/fs.h
>>>> @@ -1517,6 +1517,11 @@ struct super_block {
>>>>  	/* Pending fsnotify inode refs */
>>>>  	atomic_long_t s_fsnotify_inode_refs;
>>>>  
>>>> +#ifdef CONFIG_SECURITY_LANDLOCK
>>>> +	/* References to Landlock underlying objects */
>>>> +	atomic_long_t s_landlock_inode_refs;
>>>> +#endif
>>>> +
>>> This needs to be converted to the LSM API via superblock blob stacking.
>>>
>>> See Casey's old patch: 
>>> https://lore.kernel.org/linux-security-module/20190829232935.7099-2-casey@schaufler-ca.com/
>> s_landlock_inode_refs is quite similar to s_fsnotify_inode_refs, but I
>> can do it once the superblock security blob patch is upstream. Is it a
>> blocker for now? What is the current status of lbs_superblock?
> 
> As no currently stackable modules conflict over the superblock
> (SELinux and Smack are the existing users) there has been no need
> to move its management into the infrastructure. The active push for
> stacking does not (yet) include everything needed for SELinux+Smack.
> It includes what is needed for SELinux+AppArmor and Smack+AppArmor.
> That does not include the superblock blob.
> 
> You can include a patch in the landlock set that provides infrastructure
> management of the superblock blob. Feel free to glean it from my proposal.

OK, I'll add it to the next series.