Bug 1965001

Summary:	Fix possible AVC denial when copystat-ing some /proc/sys/vm/ files
Product:	Red Hat Enterprise Linux 8	Reporter:	Pavel Moravec <pmoravec>
Component:	sos	Assignee:	Pavel Moravec <pmoravec>
Status:	CLOSED ERRATA	QA Contact:	Miroslav Hradílek <mhradile>
Severity:	medium	Docs Contact:
Priority:	high
Version:	---	CC:	agk, bmr, mhradile, plambri, sbradley, theute
Target Milestone:	beta	Keywords:	Triaged
Target Release:	---	Flags:	pm-rhel: mirror+
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	sos-4.1-3.el8	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-11-09 19:36:31 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:

Description Pavel Moravec 2021-05-26 14:07:19 UTC

Description of problem:
TL;DR: backport https://github.com/sosreport/sos/pull/2560 to RHEL8.5.

Longer version: sosreport still attempts to copystat also SELinux context of some files from /proc or /sys (when adding the files as strings, or for special device files like pipe/shmem/..). This affects newer versions of SELinux policy than what probably appears in 8.5 GA, but it will harm us once the policy is updated a bit.


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


How reproducible:
100%


Steps to Reproduce:
1. Have a SELinux policy preventing to relabel files under /tmp to system_u:object_r:sysctl_vm_t:s0 context (like /proc/sys/vm/drop_caches has).
2. Run sos report in temp dir under /tmp:
TmpDir=$(mktemp -d)
sos report -o system --batch -vvv --tmp-dir=$TmpDir
3. Check AVC denials
4. Check if all files under _collected_ /proc/sys/vm/ dir (esp drop_caches and compact_memory) has unconfined_u:object_r:user_tmp_t:s0 context and not system_u:object_r:sysctl_vm_t:s0 one, and proper mode&permissions.


Actual results:
sos reports an error:
[archive:TarFileArchive] Unable to add '/tmp/tmp.tlrpbtJP3y/sos.n4i00rxe/sosreport-pmoravec-rhel9-2021-05-26-taiozlo/proc/sys/vm/drop_caches' to archive: [Errno 13] Permission denied: '/tmp/tmp.tlrpbtJP3y/sos.n4i00rxe/sosreport-pmoravec-rhel9-2021-05-26-taiozlo/proc/sys/vm/drop_caches'

and the same for compact_memory.

AVC denials:

type=AVC msg=audit(1622032383.981:332): avc:  denied  { associate } for  pid=1456 comm="sosreport" name="compact_memory" dev="tmpfs" ino=5873 scontext=system_u:object_r:sysctl_vm_t:s0 tcontext=system_u:object_r:tmpfs_t:s0 tclass=filesystem permissive=0
type=AVC msg=audit(1622032384.292:333): avc:  denied  { associate } for  pid=1456 comm="sosreport" name="drop_caches" dev="tmpfs" ino=6374 scontext=system_u:object_r:sysctl_vm_t:s0 tcontext=system_u:object_r:tmpfs_t:s0 tclass=filesystem permissive=0


Expected results:
No sos errors, and no AVCs.


Additional info:

Comment 1 Pavel Moravec 2021-05-27 12:14:47 UTC

Yet better test is to verify, if sos_logs/sos.log does contain something like:

2021-05-27 14:11:14,526 ERROR: [archive:TarFileArchive] Unable to add '/tmp/sos.2u13ssqj/sosreport-pmoravec-rhel9-2021-05-27-oppitki/proc/sys/vm/compact_memory' to archive: [Errno 13] Permission denied: '/tmp/sos.2u13ssqj/sosreport-pmoravec-rhel9-2021-05-27-oppitki/proc/sys/vm/compact_memory'
2021-05-27 14:11:14,863 ERROR: [archive:TarFileArchive] Unable to add '/tmp/sos.2u13ssqj/sosreport-pmoravec-rhel9-2021-05-27-oppitki/proc/sys/vm/drop_caches' to archive: [Errno 13] Permission denied: '/tmp/sos.2u13ssqj/sosreport-pmoravec-rhel9-2021-05-27-oppitki/proc/sys/vm/drop_caches'

or not.

Comment 6 errata-xmlrpc 2021-11-09 19:36:31 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 (sos 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/RHEA-2021:4388