RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1839065 - Privileged containers should be unconfined_t
Summary: Privileged containers should be unconfined_t
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: container-selinux
Version: 8.3
Hardware: All
OS: All
low
medium
Target Milestone: rc
: 8.0
Assignee: Jindrich Novy
QA Contact: atomic-bugs@redhat.com
URL:
Whiteboard:
: 1896369 (view as bug list)
Depends On:
Blocks: 1186913 1793607
TreeView+ depends on / blocked
 
Reported: 2020-05-22 12:28 UTC by Olimp Bockowski
Modified: 2023-12-15 17:59 UTC (History)
18 users (show)

Fixed In Version: container-selinux-2.135.0-1.el8
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-07-21 15:32:03 UTC
Type: Bug
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)
strace with timeout (171.61 KB, text/plain)
2020-05-22 12:31 UTC, Olimp Bockowski
no flags Details


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2020:3053 0 None None None 2020-07-21 15:32:37 UTC

Description Olimp Bockowski 2020-05-22 12:28:13 UTC
Description of problem:
When inside an OCP Node (Worker or Master) using the command "oc debug node/<NODE>", the command `hostnamectl` is bloqued by SELinux, and it hangs until a connection timeout.

Version-Release number of selected component (if applicable):
any RHCOS (for versions related until 4.4)

How reproducible:
always

Steps to Reproduce:
1. oc debug node/$someNode
2. chroot /host
3. hostnamectl

Actual results:
timeout

Expected results:
working

Additional info:
other systemd tools relying on dBus API are NOT blocked by SELinux as well, such as timedatectl

AVC:
ttype=SERVICE_START msg=audit(1581591934.786:182): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=systemd-hostnamed comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'UID="root" AUID="unset"
type=USER_AVC msg=audit(1581591934.788:183): pid=20361 uid=81 auid=4294967295 ses=4294967295 subj=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 msg='avc:  denied  { send_msg } for msgtype=method_return dest=:1.1386 spid=2831744 tpid=2831743 scontext=system_u:system_r:systemd_hostnamed_t:s0 tcontext=system_u:system_r:spc_t:s0 tclass=dbus permissive=0  exe="/usr/bin/dbus-daemon" sauid=81 hostname=? addr=? terminal=?'UID="dbus" AUID="unset" SAUID="dbus"
type=SERVICE_STOP msg=audit(1581591964.829:184): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=systemd-hostnamed comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'UID="root" AUID="unset"

Comment 1 Olimp Bockowski 2020-05-22 12:31:56 UTC
Created attachment 1691053 [details]
strace with timeout

Comment 2 Olimp Bockowski 2020-05-22 12:33:45 UTC
 DBUS daemon fails to forward a reply message from systemd to hostnamectl, this would explain why hostnamectl times out

Comment 3 Micah Abbott 2020-05-22 13:44:43 UTC
Setting as low priority as this doesn't appear to impede functionality of the cluster.

Comment 4 Derrick Ornelas 2020-05-29 15:11:56 UTC
Is this really expected to work?  Either way it seems like a SELinux issue, unrelated to RHCOS.

I can reproduce it on RHEL 8:

# podman run --rm -ti --privileged -v /:/host registry.access.redhat.com/ubi8

[root@70b2ffa3f3a7 /]# chroot /host/

sh-4.4# time hostnamectl
Failed to query system properties: Connection timed out

real	0m25.021s
user	0m0.004s
sys	0m0.006s

Comment 5 Colin Walters 2020-05-29 17:08:01 UTC
Yes, it's a base podman/container-selinux problem.

I basically don't understand the rationale behind spc_t.  Anything that's spc_t can easily "escape" to unconfined_t by e.g. `systemd-run` or destroy the system via rm -rf /host or whatever.

We just keep hitting random "unconfined_t can do it but spc_t can't" problems that impede us managing and debugging the operating system via containers.

I tried this but something seems to be denying it:

```
$ podman run --privileged --security-opt=label=type:unconfined_t --rm -ti registry.access.redhat.com/ubi8/ubi:latest
{"msg":"exec container process `/bin/bash`: Permission denied","level":"error","time":"2020-05-29T17:03:20.000206344Z"}
```

Got a bit farther with this:
```
podman run --privileged --security-opt=label=user:unconfined_u,role:unconfined_r,type:unconfined_t --rm -ti registry.access.redhat.com/ubi8/ubi:latest
Error: failed to mount shm tmpfs "/var/lib/containers/storage/overlay-containers/b4fa6193d72291cf30de73d639c8ecaa6af5367ad3d359bb69e0aa72fc253dc3/userdata/shm": invalid argument
```

And the real problem there seems to be:
```
[251727.698188] SELinux: security_context_str_to_sid(unconfined_u,role:unconfined_r,type:unconfined_t:object_r:container_file_t:s0:c32,c492) failed for (dev tmpfs, type tmpfs) errno=-22
```

So I think the RFE here is: add an option to the container stack that lets us be unconfined_t - or stated more generally, have a container image act as closely as possible as if it's run from a root shell.

(This is a bit of a debatable topic whether it should be unconfined_t or init_t; we might need both)

Comment 6 Colin Walters 2020-05-29 17:34:30 UTC
Another case for example is https://github.com/openshift/cluster-network-operator/pull/477
where we were actively fighting spc_t because we want a container image to manage openvswitch on the host, and
it turned into a mess of spc_t and openvswitch_t, whereas it's completely fine to manage openvswitch via the usual unconfined_t.

Comment 7 Daniel Walsh 2020-05-29 17:41:48 UTC
Fixed in https://github.com/containers/container-selinux/releases/tag/v2.135.0

This allows you to specify

# podman run -ti  --security-opt label=type:unconfined_t fedora cat /proc/self/attr/current 
Trying to pull registry.fedoraproject.org/fedora...
Getting image source signatures
Copying blob 1657ffead824 [--------------------------------------] 0.0b / 0.0b
Copying config eb7134a03c done  
Writing manifest to image destination
Storing signatures
system_u:system_r:unconfined_t:s0:c290,c962

Or to define it in the kubernetes yaml.

Comment 8 Colin Walters 2020-05-29 17:58:59 UTC
Awesome, thank you!  Can we get this backported to 8.3?

Comment 9 Tom Sweeney 2020-05-29 18:17:43 UTC
Assigning to Jindrich for packaging needs.  Jindrich can you also answer Colin's question in https://bugzilla.redhat.com/show_bug.cgi?id=1839065#c8 please?

Comment 10 Daniel Walsh 2020-05-29 18:33:03 UTC
Yes we should be able to get this on 8.3, I have no problem on shipping it in 8.2.1 as well.

Comment 11 Jindrich Novy 2020-05-31 05:48:59 UTC
(In reply to Colin Walters from comment #8)
> Awesome, thank you!  Can we get this backported to 8.3?

Yes, it's now in 8.3.0 as well.

Comment 12 Jindrich Novy 2020-05-31 05:49:55 UTC
Can we get QA ack on this one please?

Comment 14 Jindrich Novy 2020-06-01 06:21:45 UTC
Dan, can you please answer the three questions in comment #13 ? It is now required for 8.2.1 exception+. Thanks.

Comment 15 Colin Walters 2020-06-01 14:14:11 UTC
I think we could probably live with having this just in 8.3.

Comment 20 Joy Pu 2020-06-03 11:21:25 UTC
Test with podman-1.9.3-1.module+el8.2.1+6750+e53a300c.x86_64 and container-selinux-2.135.0-1.module+el8.2.1+6849+893e4f4a.noarch with --security-opt label=type:unconfined_t now it works as expect. So set this to verified.
Details:
#  podman run --rm -ti --privileged --security-opt label=type:unconfined_t  -v /:/host registry.access.redhat.com/ubi8
[root@83ef1574f3c2 /]# chroot /host
sh-4.4# time hostnamectl
   Static hostname: ibm-x3250m6-05.lab.eng.pek2.redhat.com
         Icon name: computer-server
           Chassis: server
        Machine ID: 28183d0c95ce4e2da2c950a11992c7e1
           Boot ID: e2b076d01d2c49fb946142f3a9aab571
  Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
       CPE OS Name: cpe:/o:redhat:enterprise_linux:8.2:GA
            Kernel: Linux 4.18.0-193.1.2.el8_2.x86_64
      Architecture: x86-64

real	0m0.270s
user	0m0.005s
sys	0m0.000s
sh-4.4# exit
exit
[root@83ef1574f3c2 /]# exit
exit

Comment 23 Colin Walters 2020-07-07 14:01:40 UTC
In the meantime, we're hitting issues like this:

type=AVC msg=audit(1594130128.905:155): avc: denied { write } for pid=523559 comm="test2" name="yum.repos.d" dev="dm-0" ino=220215514 scontext=system_u:
system_r:init_t:s0 tcontext=system_u:object_r:system_conf_t:s0 tclass=dir permissive=0`

Where in order to "escape" spc_t we're using systemd-run to run code as init_t, but that domain itself is denied to do some things.

Ultimately we need a fully privileged domain capable of *all* systems management - that is unconfined_t and not e.g. init_t right?
Compare with how e.g. Ansible works by logging in over ssh - that code hence runs as unconfined_t, which means it works differently than doing systems management via a systemd unit or a container.

If with this we're agreed to use unconfined_t, let's be sure that we have well defined mechanisms to transition to that domain from the other cases (e.g. a systemd unit).
-

Comment 27 errata-xmlrpc 2020-07-21 15:32:03 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:3053

Comment 28 Colin Walters 2020-11-10 18:55:46 UTC
*** Bug 1896369 has been marked as a duplicate of this bug. ***

Comment 29 Red Hat Bugzilla 2023-09-14 06:01:03 UTC
The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days


Note You need to log in before you can comment on or make changes to this bug.