From: Kees Cook <keescook@chromium.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Paul Moore <paul@paul-moore.com>,
linux-security-module <linux-security-module@vger.kernel.org>,
James Morris <jmorris@namei.org>,
LKML <linux-kernel@vger.kernel.org>,
SE Linux <selinux@tycho.nsa.gov>,
John Johansen <john.johansen@canonical.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Stephen Smalley <sds@tycho.nsa.gov>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Schaufler, Casey" <casey.schaufler@intel.com>
Subject: Re: [PATCH 10/10] LSM: Blob sharing support for S.A.R.A and LandLock
Date: Fri, 14 Sep 2018 13:05:07 -0700 [thread overview]
Message-ID: <CAGXu5jL2LjPhLsx2bQJQdj4GraTDakYTqb3fqUbWGrOfUsW8=w@mail.gmail.com> (raw)
In-Reply-To: <2bc5e4f5-8429-6843-f255-8fab6dacf39b@schaufler-ca.com>
On Fri, Sep 14, 2018 at 8:57 AM, Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 9/13/2018 5:19 PM, Kees Cook wrote:
>> We already have the minor LSMs that cannot change order.
>
> Are you saying that we don't have a mechanism to change
> the order, or that they wouldn't work right in a different
> order? Well, there's the capability module that has to be
> first.
I just meant their order is explicit in security.c.
>> They aren't
>> part of security= parsing either.
>
> True, but there's no reason now that we couldn't change that.
> Except for capability. Hmm.
Right, we have at least one that MUST be first (and must not be disabled).
>> Should "blob-sharing" LSMs be like major LSMs or minor LSMs?
>
> I like the idea of changing the minor modules to do the full
> registration process. That would make them all the same.
> Except for capability. In any case, the "blob-sharing" LSMs
> need to do the full registration process to account for their
> blobs sizes, and that brings the "major" behavior along with it.
I agree. I'm working on some clean-ups that I'll send out soon, though
I'm worried about some of the various boot-time options...
>> If someone is booting with "security=selinux,tomoyo" and then SARA
>> lands upstream, does that person have to explicitly add "sara" to
>> their boot args, since they're doing a non-default list of LSMs?
>
> Yes. security= is explicit.
>
>> (I actually prefer the answer being "yes" here, FWIW, I just want to
>> nail down the expectations.)
>
> For now let's leave the minor (capability, yama, loadpin) as they are,
> and require all new modules of any flavor to use full registration.
I would even be fine to convert yama and loadpin.
> We could consider something like
>
> security=$lsm # Stack with $lsm at priority 2 - Existing behavior
> $lsm.stacked=N # Add $lsm to the stack at priority N. Delete if N == 0
>
> It's OK to specify "selinux.stacked=2" and "sara.stacked=2". Which gets
> called first is left up to the system to decide. Whatever the behavior is
> gets documented. Capability will always be first and have priority 1.
> It's OK to specify "smack.stacked=1".
I'm less excited about this kind of stacking priority, but, whatever
the case, I think my cleanups may help with whatever we decide.
> The default stack is determined by CONFIG_SECURITY_$lsm_STACKED at
> build time. CONFIG_SECURITY_$lsm_STACKED changes from a boolean to
> an integer value to establish the default hook order.
>
> /sys/kernel/security/lsm reports the modules in hook call order.
Didn't I send a patch to new-line terminate this list? I always get
annoyed when I "cat" it. ;)
> /sys/kernel/security/lsm-stack reports the list with the hook call priority
>
> capability:1,yama:1,selinux:1,sara:5,landlack:17
>
> If stacking is not configured $lsm.stacked=0 is treated as security=none.
> For other values of N $lsm.stacked=N is treated as security=$lsm.
I feel like "order" is bad enough. Can we avoid adding "priority"?
-Kees
--
Kees Cook
Pixel Security
next prev parent reply other threads:[~2018-09-15 1:21 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-11 16:26 [PATCH v2 00/10] LSM: Module stacking in support of S.A.R.A and Landlock Casey Schaufler
2018-09-11 16:41 ` [PATCH 01/10] procfs: add smack subdir to attrs Casey Schaufler
2018-09-12 22:57 ` Kees Cook
2018-09-11 16:41 ` [PATCH 02/10] Smack: Abstract use of cred security blob Casey Schaufler
2018-09-12 23:04 ` Kees Cook
2018-09-11 16:41 ` [PATCH 03/10] SELinux: " Casey Schaufler
2018-09-12 23:10 ` Kees Cook
2018-09-11 16:41 ` [PATCH 04/10] LSM: Infrastructure management of the " Casey Schaufler
2018-09-12 23:53 ` Kees Cook
2018-09-13 19:01 ` Casey Schaufler
2018-09-13 21:12 ` Kees Cook
2018-09-11 16:41 ` [PATCH 05/10] SELinux: Abstract use of file " Casey Schaufler
2018-09-12 23:54 ` Kees Cook
2018-09-11 16:42 ` [PATCH 06/10] LSM: Infrastructure management of the " Casey Schaufler
2018-09-13 0:00 ` Kees Cook
2018-09-11 16:42 ` [PATCH 07/10] SELinux: Abstract use of inode " Casey Schaufler
2018-09-13 0:23 ` Kees Cook
2018-09-11 16:42 ` [PATCH 08/10] Smack: " Casey Schaufler
2018-09-13 0:24 ` Kees Cook
2018-09-11 16:42 ` [PATCH 09/10] LSM: Infrastructure management of the inode security Casey Schaufler
2018-09-13 0:30 ` Kees Cook
2018-09-11 16:42 ` [PATCH 10/10] LSM: Blob sharing support for S.A.R.A and LandLock Casey Schaufler
2018-09-13 4:19 ` Kees Cook
2018-09-13 13:16 ` Paul Moore
2018-09-13 15:19 ` Kees Cook
2018-09-13 19:12 ` Paul Moore
2018-09-13 20:58 ` Jordan Glover
2018-09-13 21:50 ` Paul Moore
2018-09-13 22:04 ` Jordan Glover
2018-09-13 23:01 ` Casey Schaufler
2018-09-13 21:01 ` Kees Cook
2018-09-13 21:38 ` Paul Moore
2018-09-13 21:51 ` Kees Cook
2018-09-13 23:06 ` Kees Cook
2018-09-13 23:32 ` John Johansen
2018-09-13 23:51 ` Kees Cook
2018-09-14 0:03 ` Casey Schaufler
2018-09-14 0:06 ` Kees Cook
2018-09-13 23:51 ` Casey Schaufler
2018-09-13 23:57 ` Kees Cook
2018-09-14 0:08 ` Casey Schaufler
2018-09-14 0:19 ` Kees Cook
2018-09-14 15:57 ` Casey Schaufler
2018-09-14 20:05 ` Kees Cook [this message]
2018-09-14 20:47 ` Casey Schaufler
2018-09-14 18:18 ` James Morris
2018-09-14 18:23 ` John Johansen
2018-09-14 0:03 ` Kees Cook
2018-09-14 2:42 ` Paul Moore
2018-09-11 20:43 ` [PATCH v2 00/10] LSM: Module stacking in support of S.A.R.A and Landlock James Morris
2018-09-12 21:29 ` James Morris
2018-09-16 16:54 ` Salvatore Mesoraca
2018-09-16 17:25 ` Casey Schaufler
2018-09-16 17:45 ` Salvatore Mesoraca
2018-09-18 7:44 ` Mickaël Salaün
2018-09-18 15:23 ` Casey Schaufler
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