From: "Mickaël Salaün" <mic@digikod.net>
To: Casey Schaufler <casey@schaufler-ca.com>,
Kees Cook <keescook@chromium.org>
Cc: John Johansen <john.johansen@canonical.com>,
James Morris <jmorris@namei.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Paul Moore <paul@paul-moore.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
"Schaufler, Casey" <casey.schaufler@intel.com>,
LSM <linux-security-module@vger.kernel.org>,
LKLM <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 16/18] LSM: Allow arbitrary LSM ordering
Date: Tue, 18 Sep 2018 01:47:00 +0200 [thread overview]
Message-ID: <968ac661-ad5d-c6e2-1587-971b6dceaaea@digikod.net> (raw)
In-Reply-To: <3a90fe88-d74a-2c2c-c949-cabcaad2e1da@schaufler-ca.com>
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On 9/18/18 01:30, Casey Schaufler wrote:
> On 9/17/2018 4:20 PM, Kees Cook wrote:
>> On Mon, Sep 17, 2018 at 4:10 PM, Mickaël Salaün <mic@digikod.net> wrote:
>>> Landlock, because it target unprivileged users, should only be called
>>> after all other major (access-control) LSMs. The admin or distro must
>>> not be able to change that order in any way. This constraint doesn't
>>> apply to current LSMs, though.
>
> What harm would it cause for Landlock to get called before SELinux?
> I certainly see why it seems like it ought to get called after, but
> would it really make a difference?
If an unprivileged process is able to infer some properties of a file
being requested (thanks to one of its eBPF program doing checks on this
process accesses), whereas this file access would be denied by a
privileged LSM, then there is a side channel attack allowing this
process to indirectly get information otherwise inaccessible.
In other words, an unprivileged process should not be allowed to sneak
itself (via an eBPF program) before SELinux for instance. SELinux should
be able to block such information gathering the same way it can block a
fstat(2) requested by a process.
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next prev parent reply other threads:[~2018-09-17 23:48 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-16 0:30 [PATCH 00/18] LSM: Prepare for explict LSM ordering Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 01/18] vmlinux.lds.h: Avoid copy/paste of security_init section Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 02/18] LSM: Rename .security_initcall section to .lsm_info Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 03/18] LSM: Remove initcall tracing Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 04/18] LSM: Convert from initcall to struct lsm_info Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 05/18] vmlinux.lds.h: Move LSM_TABLE into INIT_DATA Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 06/18] LSM: Convert security_initcall() into DEFINE_LSM() Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 07/18] LSM: Add minor LSM initialization loop Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 1:27 ` Jann Horn
2018-09-16 1:27 ` Jann Horn
2018-09-16 1:49 ` Kees Cook
2018-09-16 1:49 ` Kees Cook
2018-09-16 0:30 ` [PATCH 08/18] integrity: Initialize as LSM_TYPE_MINOR Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 09/18] LSM: Record LSM name in struct lsm_info Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 10/18] LSM: Plumb visibility into optional "enabled" state Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 11/18] LSM: Lift LSM selection out of individual LSMs Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 1:32 ` Jann Horn
2018-09-16 1:32 ` Jann Horn
2018-09-16 1:47 ` Kees Cook
2018-09-16 1:47 ` Kees Cook
2018-09-16 0:30 ` [PATCH 12/18] LSM: Introduce ordering details in struct lsm_info Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 13/18] LoadPin: Initialize as LSM_TYPE_MINOR Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 14/18] Yama: " Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 15/18] capability: " Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 16/18] LSM: Allow arbitrary LSM ordering Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 18:49 ` Casey Schaufler
2018-09-16 18:49 ` Casey Schaufler
2018-09-16 23:00 ` Kees Cook
2018-09-16 23:00 ` Kees Cook
2018-09-17 0:46 ` Tetsuo Handa
2018-09-17 0:46 ` Tetsuo Handa
2018-09-17 15:06 ` Casey Schaufler
2018-09-17 15:06 ` Casey Schaufler
2018-09-17 16:24 ` Kees Cook
2018-09-17 16:24 ` Kees Cook
2018-09-17 17:13 ` Casey Schaufler
2018-09-17 17:13 ` Casey Schaufler
2018-09-17 18:14 ` Kees Cook
2018-09-17 18:14 ` Kees Cook
2018-09-17 19:23 ` Casey Schaufler
2018-09-17 19:23 ` Casey Schaufler
2018-09-17 19:55 ` John Johansen
2018-09-17 19:55 ` John Johansen
2018-09-17 21:57 ` Casey Schaufler
2018-09-17 21:57 ` Casey Schaufler
2018-09-17 22:36 ` John Johansen
2018-09-17 22:36 ` John Johansen
2018-09-17 23:10 ` Mickaël Salaün
2018-09-17 23:20 ` Kees Cook
2018-09-17 23:20 ` Kees Cook
2018-09-17 23:26 ` John Johansen
2018-09-17 23:26 ` John Johansen
2018-09-17 23:28 ` Kees Cook
2018-09-17 23:28 ` Kees Cook
2018-09-17 23:40 ` Casey Schaufler
2018-09-17 23:40 ` Casey Schaufler
2018-09-17 23:30 ` Casey Schaufler
2018-09-17 23:30 ` Casey Schaufler
2018-09-17 23:47 ` Mickaël Salaün [this message]
2018-09-18 0:00 ` Casey Schaufler
2018-09-18 0:00 ` Casey Schaufler
2018-09-17 23:25 ` John Johansen
2018-09-17 23:25 ` John Johansen
2018-09-17 23:25 ` Casey Schaufler
2018-09-17 23:25 ` Casey Schaufler
2018-09-18 0:00 ` Kees Cook
2018-09-18 0:00 ` Kees Cook
2018-09-18 0:24 ` Casey Schaufler
2018-09-18 0:24 ` Casey Schaufler
2018-09-18 0:45 ` Kees Cook
2018-09-18 0:45 ` Kees Cook
2018-09-18 0:57 ` Casey Schaufler
2018-09-18 0:57 ` Casey Schaufler
2018-09-18 0:59 ` Kees Cook
2018-09-18 0:59 ` Kees Cook
2018-09-18 1:08 ` John Johansen
2018-09-18 1:08 ` John Johansen
2018-09-17 19:35 ` John Johansen
2018-09-17 19:35 ` John Johansen
2018-09-16 0:30 ` [PATCH 17/18] LSM: Provide init debugging Kees Cook
2018-09-16 0:30 ` Kees Cook
2018-09-16 0:30 ` [PATCH 18/18] LSM: Don't ignore initialization failures Kees Cook
2018-09-16 0:30 ` Kees Cook
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