From: Frederick Lawler <fred@cloudflare.com>
To: kpsingh@kernel.org, revest@chromium.org, jackmanb@chromium.org,
ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
john.fastabend@gmail.com, jmorris@namei.org, serge@hallyn.com,
paul@paul-moore.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
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
kernel-team@cloudflare.com,
Frederick Lawler <fred@cloudflare.com>
Subject: [PATCH v2 0/4] Introduce security_create_user_ns()
Date: Thu, 7 Jul 2022 17:32:24 -0500 [thread overview]
Message-ID: <20220707223228.1940249-1-fred@cloudflare.com> (raw)
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 create_user_ns LSM hook, then marks the hook as sleepable in BPF.
Links:
1. https://lore.kernel.org/all/20220608150942.776446-1-fred@cloudflare.com/
2. https://lore.kernel.org/all/87y1xzyhub.fsf@email.froward.int.ebiederm.org/
3. https://lore.kernel.org/all/9fe9cd9f-1ded-a179-8ded-5fde8960a586@cloudflare.com/
Changes since v1:
- Add selftests/bpf: Add tests verifying bpf lsm create_user_ns hook patch
- Add selinux: Implement create_user_ns hook patch
- Change function signature of security_create_user_ns() to only take
struct cred
- Move security_create_user_ns() call after id mapping check in
create_user_ns()
- Update documentation to reflect changes
Frederick Lawler (4):
security, lsm: Introduce security_create_user_ns()
bpf-lsm: Make bpf_lsm_create_user_ns() sleepable
selftests/bpf: Add tests verifying bpf lsm create_user_ns hook
selinux: Implement create_user_ns hook
include/linux/lsm_hook_defs.h | 1 +
include/linux/lsm_hooks.h | 4 +
include/linux/security.h | 6 ++
kernel/bpf/bpf_lsm.c | 1 +
kernel/user_namespace.c | 5 ++
security/security.c | 5 ++
security/selinux/hooks.c | 9 ++
security/selinux/include/classmap.h | 2 +
.../selftests/bpf/prog_tests/deny_namespace.c | 88 +++++++++++++++++++
.../selftests/bpf/progs/test_deny_namespace.c | 39 ++++++++
10 files changed, 160 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/deny_namespace.c
create mode 100644 tools/testing/selftests/bpf/progs/test_deny_namespace.c
--
2.30.2
next reply other threads:[~2022-07-07 22:32 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-07 22:32 Frederick Lawler [this message]
2022-07-07 22:32 ` [PATCH v2 1/4] security, lsm: Introduce security_create_user_ns() Frederick Lawler
2022-07-07 22:32 ` [PATCH v2 2/4] bpf-lsm: Make bpf_lsm_create_user_ns() sleepable Frederick Lawler
2022-07-07 22:32 ` [PATCH v2 3/4] selftests/bpf: Add tests verifying bpf lsm create_user_ns hook Frederick Lawler
2022-07-07 22:32 ` [PATCH v2 4/4] selinux: Implement " Frederick Lawler
2022-07-20 1:32 ` Paul Moore
2022-07-20 14:57 ` Frederick Lawler
[not found] ` <CA+EEuAhfMrg=goGhWxVW2=i4Z7mVN4GvfzettvX8T+tFcOPKCw@mail.gmail.com>
2022-07-20 14:52 ` Paul Moore
2022-07-08 12:10 ` [PATCH v2 0/4] Introduce security_create_user_ns() Christian Göttsche
2022-07-08 14:01 ` Frederick Lawler
2022-07-08 14:35 ` Christian Brauner
2022-07-08 16:11 ` Casey Schaufler
2022-07-14 14:27 ` Serge E. Hallyn
2022-07-19 19:59 ` Frederick Lawler
2022-07-20 1:32 ` Paul Moore
2022-07-20 21:42 ` Casey Schaufler
2022-07-20 22:39 ` Paul Moore
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220707223228.1940249-1-fred@cloudflare.com \
--to=fred@cloudflare.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=brauner@kernel.org \
--cc=casey@schaufler-ca.com \
--cc=daniel@iogearbox.net \
--cc=ebiederm@xmission.com \
--cc=eparis@parisplace.org \
--cc=jackmanb@chromium.org \
--cc=jmorris@namei.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kernel-team@cloudflare.com \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=paul@paul-moore.com \
--cc=revest@chromium.org \
--cc=selinux@vger.kernel.org \
--cc=serge@hallyn.com \
--cc=shuah@kernel.org \
--cc=songliubraving@fb.com \
--cc=stephen.smalley.work@gmail.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).