Bug 1749870

Summary:	SELinux is preventing pcp-pmda-named from executing /usr/sbin/rndc
Product:	Red Hat Enterprise Linux 7	Reporter:	Jan Kurik <jkurik>
Component:	pcp	Assignee:	Nathan Scott <nathans>
Status:	CLOSED ERRATA	QA Contact:	Jan Kurik <jkurik>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.8	CC:	agerstmayr, jkurik, lmiksik, mgoodwin, nathans, patrickm
Target Milestone:	rc	Keywords:	Bugfix, Triaged
Target Release:	7.9
Hardware:	All
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	No Doc Update
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-09-29 19:24:55 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:	1782202

Description Jan Kurik 2019-09-06 15:46:48 UTC

Description of problem:
pcp-pmda-named uses /usr/sbin/rndc to get data from named.
Unfortunately when pcp-pmda-named executes /usr/sbin/rndc the execution fails due to missing SELinux rule allowing the execution of rndc.


Version-Release number of selected component (if applicable):
pcp-4.3.2-6.el7.x86_64
selinux-policy-3.13.1-258.el7.noarch
pcp-selinux-4.3.2-6.el7.x86_64
pcp-pmda-named-4.3.2-6.el7.x86_64


How reproducible:
Always

Steps to Reproduce:
1. Install pcp with pcp-pmda-named
2. Install bind, bind-chroot, caching-nameserver, bind-utils packages
3. Configure bind as a caching nameserver
4. Start PCP as well as bind
5. Use i.e. "dig @127.0.0.1" to query DNS

Actual results:
Output of "audit2allow -a" shows:
<stdout>
#============= pcp_pmcd_t ==============
allow pcp_pmcd_t ndc_exec_t:file execute;
</stdout>

Expected results:
Output of "audit2allow -a" should be empty


Additional info:

Comment 5 Nathan Scott 2020-04-05 23:07:21 UTC

Hmm, strange - the policy patch definitely has these changes...

$ grep ndc_exec_t *
selinux-policy.patch:+  allow [pcp_pmcd_t] [ndc_exec_t] : [file] { execute };
selinux-policy.patch:+        type ndc_exec_t;
selinux-policy.patch:+allow pcp_pmcd_t ndc_exec_t:file execute;

Bit of a mystery - is the AVC exactly the same as before Jan?  Thanks.

Comment 6 Jan Kurik 2020-04-06 05:31:18 UTC

You are right Nathan, it is a different AVC. I am sorry for the confusion.

The AVC it is throwing now is:

# grep 'type=AVC ' /var/log/audit/audit.log | head -n 1
type=AVC msg=audit(1586150510.119:1454): avc:  denied  { execute_no_trans } for  pid=30473 comm="perl" path="/usr/sbin/rndc" dev="vda1" ino=7449669 scontext=system_u:system_r:pcp_pmcd_t:s0 tcontext=system_u:object_r:ndc_exec_t:s0 tclass=file permissive=0

# audit2allow -a
#============= pcp_pmcd_t ==============
allow pcp_pmcd_t ndc_exec_t:file execute_no_trans;


When I apply this ^^^ selinux rule, the test is then passing.
Should I open a new bug for this ?

Comment 7 Nathan Scott 2020-04-06 05:36:40 UTC

> Should I open a new bug for this ?

Yes please Jan.  Since its relatively low priority and readily worked around, let's aim for 7.10 for that one, unless there's some other need for a 7.9 rebuild.

Comment 8 Jan Kurik 2020-04-06 05:52:00 UTC

Here is the follow-up: BZ1821122

Comment 10 errata-xmlrpc 2020-09-29 19:24:55 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 (Low: pcp security, 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/RHSA-2020:3869