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 2101341 - AVC when executing "subscription-manager" as sudo'ed sysadm_t
Summary: AVC when executing "subscription-manager" as sudo'ed sysadm_t
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: selinux-policy
Version: 8.6
Hardware: All
OS: Linux
low
low
Target Milestone: rc
: 8.8
Assignee: Zdenek Pytela
QA Contact: Milos Malik
Petr Hybl
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2022-06-27 08:45 UTC by Renaud Métrich
Modified: 2023-05-16 11:00 UTC (History)
6 users (show)

Fixed In Version: selinux-policy-3.14.3-109.el8
Doc Type: Bug Fix
Doc Text:
.SELinux policy allows `sysadm_r` to use `subscription-manager` Previously, users in the `sysadm_r` SELinux role were not allowed to execute some subcommands of the `subscription-manager` utility. Consequently, the subcommands failed to read the memory device. This update adds a new rule to the SELinux policy that allows the `sysadm_t type` to read `/dev/mem`. As a consequence, the `subscription-manager` subcommands do not fail.
Clone Of:
Environment:
Last Closed: 2023-05-16 09:03:44 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github fedora-selinux selinux-policy pull 1333 0 None Merged Allow sysadm_t read raw memory devices 2022-12-08 16:21:21 UTC
Red Hat Issue Tracker RHELPLAN-126332 0 None None None 2022-06-27 08:56:42 UTC
Red Hat Knowledge Base (Solution) 6964979 0 None None None 2022-06-28 07:03:59 UTC
Red Hat Product Errata RHBA-2023:2965 0 None None None 2023-05-16 09:04:03 UTC

Description Renaud Métrich 2022-06-27 08:45:54 UTC 
Description of problem:

Users mapped to sysadm_u get AVCs when executing "subscription-manager register" command (but also "subscription-manager repos"):
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
type=PROCTITLE msg=audit(06/27/2022 09:37:51.112:127) : proctitle=/usr/libexec/platform-python /sbin/subscription-manager register --username rhn-support-rmetrich 
type=SYSCALL msg=audit(06/27/2022 09:37:51.112:127) : arch=x86_64 syscall=openat success=no exit=EACCES(Permission denied) a0=AT_FDCWD a1=0x7f5c6f4f6a63 a2=O_RDONLY a3=0x0 items=0 ppid=1687 pid=1795 auid=sysadm uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=pts0 ses=2 comm=subscription-ma exe=/usr/libexec/platform-python3.6 subj=sysadm_u:sysadm_r:sysadm_t:s0-s0:c0.c1023 key=(null) 
type=AVC msg=audit(06/27/2022 09:37:51.112:127) : avc:  denied  { read } for  pid=1795 comm=subscription-ma name=mem dev="devtmpfs" ino=9361 scontext=sysadm_u:sysadm_r:sysadm_t:s0-s0:c0.c1023 tcontext=system_u:object_r:memory_device_t:s0 tclass=chr_file permissive=0 
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Even though that read fails, the command *seems* to be a success in the end.
I get this while reproducing an issue for a customer having RHEL7, but here above it's RHEL8.

Version-Release number of selected component (if applicable):

subscription-manager-1.28.29-3.el8.x86_64
selinux-policy-targeted-3.14.3-95.el8.noarch

How reproducible:

Always

Steps to Reproduce:
1. Setup an admin user mapped to "staff_u" or "sysadm_u"
2. Login as the user and "sudo -r sysadm_r -t sysadm_t -i"
3. Execute "subscription-manager register" command

Actual results:

AVC above

Expected results:

No AVC
Comment 1 Zdenek Pytela 2022-08-10 11:29:21 UTC 
Pino,

subscription manager seems to request reading of /dev/mem directly: is this expected and should we allow it in the policy?
Comment 2 Pino Toscano 2022-08-11 03:42:25 UTC 
(In reply to Zdenek Pytela from comment #1)
> subscription manager seems to request reading of /dev/mem directly: is this
> expected and should we allow it in the policy?

Unfortunately it is expected: we use python-dmidecode to read SMBIOS/DMI details of the system, and that Python module reads /dev/mem directly.

Curiously enough: this way does not work in kernel_lockdown mode, enforced when Secure Boot is enabled by newer kernels.
In particular, subscription-manager in RHEL 9 had to switch away from python-dmidecode: bug 2101341.
(It was changed in 9.0z released a couple of days ago, and of course in 9.1.)

It is interesting that this came up only now, as subscription-manager had been using python-dmidecode for many years.

So yeah, in RHEL 8 we need this SELinux rule.
Comment 5 Zdenek Pytela 2022-08-11 14:44:33 UTC 
(In reply to Pino Toscano from comment #2)
> > subscription manager seems to request reading of /dev/mem directly: is this
> > expected and should we allow it in the policy?
> 
> Unfortunately it is expected: we use python-dmidecode to read SMBIOS/DMI
> details of the system, and that Python module reads /dev/mem directly.
> 
> Curiously enough: this way does not work in kernel_lockdown mode, enforced
> when Secure Boot is enabled by newer kernels.
> In particular, subscription-manager in RHEL 9 had to switch away from
> python-dmidecode: bug 2101341.
> (It was changed in 9.0z released a couple of days ago, and of course in 9.1.)
> 
> It is interesting that this came up only now, as subscription-manager had
> been using python-dmidecode for many years.
I suppose this only pops up when SELinux confined users are in place, see the attached KCS for reproducer.

> So yeah, in RHEL 8 we need this SELinux rule.
Thank you.
Comment 6 Zdenek Pytela 2022-08-29 16:24:35 UTC 
Commit to backport:
commit c95cf07cea17f548daee8f47b9580120b63dedc2 (HEAD -> rawhide, upstream/rawhide)
Author: Zdenek Pytela <zpytela>
Date:   Thu Aug 11 16:47:57 2022 +0200

    Allow sysadm_t read raw memory devices
Comment 20 errata-xmlrpc 2023-05-16 09:03:44 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 (selinux-policy bug fix and enhancement update), 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/RHBA-2023:2965
Note You need to log in before you can comment on or make changes to this bug.