Bug 1551568

Summary:	Cannot execute mdadm when policy is MLS
Product:	Red Hat Enterprise Linux 7	Reporter:	Renaud Métrich <rmetrich>
Component:	selinux-policy	Assignee:	Lukas Vrabec <lvrabec>
Status:	CLOSED ERRATA	QA Contact:	Milos Malik <mmalik>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.6	CC:	lvrabec, mgrepl, mmalik, plautrba, ssekidde
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	selinux-policy-3.13.1-197.el7	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	1551569 (view as bug list)		Environment:
Last Closed:	2018-10-30 10:03:08 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1551569

Description Renaud Métrich 2018-03-05 12:30:23 UTC

Description of problem:

Upon switching to MLS policy, the sysadm_r user (e.g. root) cannot execute mdadm, getting the following error:

type=SYSCALL msg=audit(): arch=c000003e syscall=59 success=no exit=-13 a0=1fff930 a1=1ffbee0 a2=2006110 a3=7ffd72116750 items=0 ppid=2877 pid=2893 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=tty2 ses=2 comm="bash" exe="/bin/bash" subj=root:sysadm_r:sysadm_t:s0-s15:c0.c1023 key=(null)
type=SELINUX_ERR msg=audit(): op=security_compute_sid invalid_context=root:sysadm_r:mdadm_t:s0-s15:c0.c1023 scontext=root:sysadm_r:sysadm_t:s0-s15:c0.c1023 tcontext=system_u:object_r:mdadm_exec_t:s0 tclass=process

lvrabec++ found root cause, fixed in Fedora: https://github.com/fedora-selinux/selinux-policy/commit/579d1bc8124a2a908d071105458a6f0f4f60e423


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

selinux-policy-mls-3.13.1-166.el7_4.7.noarch


How reproducible:

Always


Steps to Reproduce:
1. Execute "mdadm" as root user while in MLS enforcing

Actual results:

-bash: /usr/sbin/mdadm: Permission denied


Expected results:

Works

Comment 3 Milos Malik 2018-09-17 16:09:44 UTC

# id -Z
root:sysadm_r:sysadm_t:s0
# sestatus 
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             mls
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     denied
Max kernel policy version:      31
# mdadm /dev/vda
/dev/vda: is not an md array
# mdadm
Usage: mdadm --help
  for help
# 

Unfortunately, if the daemons_use_tty boolean is disabled, then mdadm is completely silent:

# setsebool daemons_use_tty off
# mdadm 
# mdadm --help
# mdadm /dev/vda
# 

Either the need to use the boolean is documented or policy needs to be improved.

# rpm -qa selinux\*
selinux-policy-sandbox-3.13.1-226.el7.noarch
selinux-policy-targeted-3.13.1-226.el7.noarch
selinux-policy-doc-3.13.1-226.el7.noarch
selinux-policy-mls-3.13.1-226.el7.noarch
selinux-policy-3.13.1-226.el7.noarch
selinux-policy-devel-3.13.1-226.el7.noarch
#

Comment 5 errata-xmlrpc 2018-10-30 10:03:08 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/RHBA-2018:3111