Bug 1439442 – NFS crossmnt AVC denied for comm="rpc.mountd" name="/" dev="configfs" ino=7990 scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:object_r:configfs_t:s0 tclass=dir

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Bug 1439442 - NFS crossmnt AVC denied for comm="rpc.mountd" name="/" dev="configfs" ino=7990 scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:object_r:configfs_t:s0 tclass=dir

Summary:	NFS crossmnt AVC denied for comm="rpc.mountd" name="/" dev="configfs" ino=799...

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	selinux-policy (Show other bugs)
Sub Component:
Version:	7.4
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	rc
Target Release:	---
Assigned To:	Lukas Vrabec
QA Contact:	Milos Malik
Docs Contact:

URL:
Whiteboard:
Keywords:	Reproducer

Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2017-04-05 22:30 EDT by Yongcheng Yang
Modified:	2018-04-10 08:32 EDT (History)
CC List:	8 users (show)

See Also:
Fixed In Version:	selinux-policy-3.13.1-176.el7
Doc Type:	If docs needed, set a value
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2018-04-10 08:29:42 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2018:0763	None	None	None	2018-04-10 08:32 EDT

Groups: None (edit)

Description Yongcheng Yang 2017-04-05 22:30:56 EDT

Description of problem:
There is an "avc denied" log during tests of NFS crossmnt (details please find from manpage exports(5)) with root "/". 

Version-Release number of selected component (if applicable):
RHEL-7.3

How reproducible:
100% easily

Steps to Reproduce:
1. echo '/ *(ro,crossmnt,nohide,no_root_squash)' > /etc/exports
2. systemctl restart nfs
3. Mount the "/" to any mount point
4. Read contents of $mountpoint/boot/

Actual results:
# echo '/ *(ro,crossmnt,nohide,no_root_squash)' >/etc/exports
# systemctl restart nfs
# mount localhost:/ /mnt/mnt_test/
# cat /var/log/audit/audit.log | grep denied
# ls /mnt/mnt_test/boot/ &>/dev/null
# cat /var/log/audit/audit.log | grep denied
type=AVC msg=audit(1491444765.616:197): avc:  denied  { search } for  pid=30483 comm="rpc.mountd" name="/" dev="configfs" ino=7560 scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:object_r:configfs_t:s0 tclass=dir
# 

Expected results:
No AVC failure.

Additional info:
Rhel6 doesn't have this warning.

Comment 2 Milos Malik 2017-04-06 06:20:32 EDT

# rpm -qa selinux-policy\*
selinux-policy-targeted-3.13.1-132.el7.noarch
selinux-policy-3.13.1-132.el7.noarch
#

SELinux denials caught in enforcing mode:
----
type=SYSCALL msg=audit(04/06/2017 06:15:15.368:282) : arch=x86_64 syscall=lstat success=no exit=EACCES(Permission denied) a0=0x55f139a83ab0 a1=0x7fffe3dda3a0 a2=0x7fffe3dda3a0 a3=0x0 items=0 ppid=1 pid=1309 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.mountd exe=/usr/sbin/rpc.mountd subj=system_u:system_r:nfsd_t:s0 key=(null) 
type=AVC msg=audit(04/06/2017 06:15:15.368:282) : avc:  denied  { search } for  pid=1309 comm=rpc.mountd name=/ dev="configfs" ino=7675 scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:object_r:configfs_t:s0 tclass=dir 
----

SELinux denials caught in permissive mode:
----
type=SYSCALL msg=audit(04/06/2017 06:17:23.320:303) : arch=x86_64 syscall=lstat success=yes exit=0 a0=0x564d6a1f27d0 a1=0x7ffdb4d18900 a2=0x7ffdb4d18900 a3=0x0 items=0 ppid=1 pid=1538 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.mountd exe=/usr/sbin/rpc.mountd subj=system_u:system_r:nfsd_t:s0 key=(null) 
type=AVC msg=audit(04/06/2017 06:17:23.320:303) : avc:  denied  { search } for  pid=1538 comm=rpc.mountd name=/ dev="configfs" ino=7675 scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:object_r:configfs_t:s0 tclass=dir 
----

Comment 9 errata-xmlrpc 2018-04-10 08:29:42 EDT

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-2018:0763

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