From: Paul Moore <paul@paul-moore.com>
To: Frederick Lawler <fred@cloudflare.com>, kpsingh@kernel.org
Cc: Martin KaFai Lau <kafai@fb.com>,
revest@chromium.org, jackmanb@chromium.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, songliubraving@fb.com,
yhs@fb.com, john.fastabend@gmail.com, jmorris@namei.org,
serge@hallyn.com, stephen.smalley.work@gmail.com,
eparis@parisplace.org, shuah@kernel.org, brauner@kernel.org,
casey@schaufler-ca.com, ebiederm@xmission.com,
bpf@vger.kernel.org, linux-security-module@vger.kernel.org,
selinux@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
kernel-team@cloudflare.com, cgzones@googlemail.com,
karl@bigbadwolfsecurity.com
Subject: Re: [PATCH v3 0/4] Introduce security_create_user_ns()
Date: Mon, 1 Aug 2022 11:19:35 -0400 [thread overview]
Message-ID: <CAHC9VhQw8LR9yJ9UkA-9aPNETQavt25G-GGSs-_ztg6ZpxNzxA@mail.gmail.com> (raw)
In-Reply-To: <a4db1154-94bc-9833-1665-a88a5eee48de@cloudflare.com>
On Mon, Aug 1, 2022 at 9:13 AM Frederick Lawler <fred@cloudflare.com> wrote:
> On 7/22/22 7:20 AM, Paul Moore wrote:
> > On July 22, 2022 2:12:03 AM Martin KaFai Lau <kafai@fb.com> wrote:
> >
> >> On Thu, Jul 21, 2022 at 12:28:04PM -0500, Frederick Lawler wrote:
> >>> While creating a LSM BPF MAC policy to block user namespace creation, we
> >>> used the LSM cred_prepare hook because that is the closest hook to prevent
> >>> a call to create_user_ns().
> >>>
> >>> The calls look something like this:
> >>>
> >>> cred = prepare_creds()
> >>> security_prepare_creds()
> >>> call_int_hook(cred_prepare, ...
> >>> if (cred)
> >>> create_user_ns(cred)
> >>>
> >>> We noticed that error codes were not propagated from this hook and
> >>> introduced a patch [1] to propagate those errors.
> >>>
> >>> The discussion notes that security_prepare_creds()
> >>> is not appropriate for MAC policies, and instead the hook is
> >>> meant for LSM authors to prepare credentials for mutation. [2]
> >>>
> >>> Ultimately, we concluded that a better course of action is to introduce
> >>> a new security hook for LSM authors. [3]
> >>>
> >>> This patch set first introduces a new security_create_user_ns() function
> >>> and userns_create LSM hook, then marks the hook as sleepable in BPF.
> >> Patch 1 and 4 still need review from the lsm/security side.
> >
> > This patchset is in my review queue and assuming everything checks out, I expect to merge it after the upcoming merge window closes.
> >
> > I would also need an ACK from the BPF LSM folks, but they're CC'd on this patchset.
>
> Based on last weeks comments, should I go ahead and put up v4 for
> 5.20-rc1 when that drops, or do I need to wait for more feedback?
In general it rarely hurts to make another revision, and I think
you've gotten some decent feedback on this draft, especially around
the BPF LSM tests; I think rebasing on Linus tree after the upcoming
io_uring changes are merged would be a good idea. Although as a
reminder to the BPF LSM folks - I'm looking at you KP Singh :) - I
need an ACK from you guys before I merge the BPF related patches
(patches {2,3}/4). For the record, I think the SELinux portion of
this patchset (path 4/4) is fine.
There is the issue of Eric's NACK, but I believe the responses that
followed his comment sufficiently addressed those concerns and it has
now been a week with no further comment from Eric; we should continue
to move forward with this.
--
paul-moore.com
next prev parent reply other threads:[~2022-08-01 15:19 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 17:28 [PATCH v3 0/4] Introduce security_create_user_ns() Frederick Lawler
2022-07-21 17:28 ` [PATCH v3 1/4] security, lsm: " Frederick Lawler
2022-07-22 8:21 ` Christian Brauner
2022-07-21 17:28 ` [PATCH v3 2/4] bpf-lsm: Make bpf_lsm_userns_create() sleepable Frederick Lawler
2022-07-22 8:18 ` Christian Brauner
2022-07-21 17:28 ` [PATCH v3 3/4] selftests/bpf: Add tests verifying bpf lsm userns_create hook Frederick Lawler
2022-07-22 6:07 ` Martin KaFai Lau
2022-07-22 13:41 ` Frederick Lawler
2022-07-22 8:15 ` Christian Brauner
2022-07-21 17:28 ` [PATCH v3 4/4] selinux: Implement " Frederick Lawler
2022-07-22 6:11 ` [PATCH v3 0/4] Introduce security_create_user_ns() Martin KaFai Lau
2022-07-22 12:20 ` Paul Moore
2022-08-01 13:13 ` Frederick Lawler
2022-08-01 15:19 ` Paul Moore [this message]
2022-08-02 21:24 ` KP Singh
2022-08-03 1:49 ` Paul Moore
2022-08-01 15:25 ` Casey Schaufler
2022-08-01 16:34 ` Paul Moore
2022-08-02 21:27 ` KP Singh
2022-08-02 21:33 ` Eric W. Biederman
2022-08-03 15:20 ` Frederick Lawler
2022-07-22 17:05 ` Eric W. Biederman
2022-07-25 22:53 ` Paul Moore
2022-07-26 12:02 ` Djalal Harouni
2022-07-26 14:41 ` Ignat Korchagin
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