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Description of problem:
vhostmd having no permission to write metrics after attaching /dev/shm/vhostmd0 to the guest.
Version-Release number of selected component (if applicable):
selinux-policy-3.13.1-165.el7.noarch
libvirt-3.2.0-14.el7.x86_64
How reproducible:
100%
Steps to Reproduce:
1.Install vhostmd and start vhostmd service:
#yum -y install vhostmd
#systemctl start vhostmd
2.Check the selinux context of /dev/shm/vhostmd0:
#ll -Z /dev/shm/vhostmd0
-rw-r--r--. root root system_u:object_r:vhostmd_tmpfs_t:s0 /dev/shm/vhostmd0
3.Attach /dev/shm/vhostmd0 to a running guest
#cat disk-vhostmd.xml
<disk type='file' device='disk'>
<driver name='qemu' type='raw'/>
<source file='/dev/shm/vhostmd0'/>
<target dev='vdb' bus='virtio'/>
</disk>
#virsh attach-device full-73 disk-vhostmd.xml
Device attached successfully
# virsh domblklist full-73
Target Source
------------------------------------------------
hdc /var/lib/libvirt/images/shareable.iso
vda /nfs-images/yafu/rhel7.2.qcow2
vdb /dev/shm/vhostmd0
4.Check the selinux context of /dev/shm/vhostmd0 after step3:
# ll -Z /dev/shm/vhostmd0
-rw-r--r--. qemu qemu system_u:object_r:svirt_image_t:s0:c195,c606 /dev/shm/vhos
5.Check the vhostmd service status after step 4:
#systemctl status vhostmd
# systemctl status vhostmd
● vhostmd.service - LSB: Virtualization host metrics daemon
Loaded: loaded (/etc/rc.d/init.d/vhostmd; bad; vendor preset: disabled)
Active: active (running) since Tue 2017-06-27 10:32:07 CST; 47min ago
Docs: man:systemd-sysv-generator(8)
Process: 29477 ExecStop=/etc/rc.d/init.d/vhostmd stop (code=exited, status=0/SUCCESS)
Process: 29489 ExecStart=/etc/rc.d/init.d/vhostmd start (code=exited, status=0/SUCCESS)
CGroup: /system.slice/vhostmd.service
└─29502 /usr/sbin/vhostmd --user vhostmd --connect qemu:///system
Jun 27 11:10:20 localhost.localdomain vhostmd[29502]: Error writing metrics disk header sig: Permission denied
Jun 27 11:11:20 localhost.localdomain vhostmd[29502]: Error writing metrics disk header sig: Permission denied
...
Actual results:
vhostmd having no permission to write metrics after attaching /dev/shm/vhostmd0 to the guest.
Expected results:
vhostmd should have permission to write metrics after attaching /dev/shm/vhostmd0 to the guest.
Additional info:
1.See the error info in the syslog:
#cat /var/log/messages
...
Jun 27 11:20:40 localhost setroubleshoot: failed to retrieve rpm info for /dev/shm/vhostmd0
Jun 27 11:20:40 localhost setroubleshoot: SELinux is preventing /usr/sbin/vhostmd from write access on the file /dev/shm/vhostmd0. For complete SELinux messages run: sealert -l 9f9673b0-4e00-41f0-bb9e-ade129b66c28
Jun 27 11:20:40 localhost python: SELinux is preventing /usr/sbin/vhostmd from write access on the file /dev/shm/vhostmd0.#012#012***** Plugin catchall (100. confidence) suggests **************************#012#012If you believe that vhostmd should be allowed write access on the vhostmd0 file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vhostmd' --raw | audit2allow -M my-vhostmd#012# semodule -i my-vhostmd.pp#012
...
Could you re-run your scenario in permissive mode and collect SELinux denials in raw form?
# ausearch -m avc -m user_avc -m selinux_err -m user_selinux_err -i -ts today
Thank you.
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
Description of problem: vhostmd having no permission to write metrics after attaching /dev/shm/vhostmd0 to the guest. Version-Release number of selected component (if applicable): selinux-policy-3.13.1-165.el7.noarch libvirt-3.2.0-14.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1.Install vhostmd and start vhostmd service: #yum -y install vhostmd #systemctl start vhostmd 2.Check the selinux context of /dev/shm/vhostmd0: #ll -Z /dev/shm/vhostmd0 -rw-r--r--. root root system_u:object_r:vhostmd_tmpfs_t:s0 /dev/shm/vhostmd0 3.Attach /dev/shm/vhostmd0 to a running guest #cat disk-vhostmd.xml <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/dev/shm/vhostmd0'/> <target dev='vdb' bus='virtio'/> </disk> #virsh attach-device full-73 disk-vhostmd.xml Device attached successfully # virsh domblklist full-73 Target Source ------------------------------------------------ hdc /var/lib/libvirt/images/shareable.iso vda /nfs-images/yafu/rhel7.2.qcow2 vdb /dev/shm/vhostmd0 4.Check the selinux context of /dev/shm/vhostmd0 after step3: # ll -Z /dev/shm/vhostmd0 -rw-r--r--. qemu qemu system_u:object_r:svirt_image_t:s0:c195,c606 /dev/shm/vhos 5.Check the vhostmd service status after step 4: #systemctl status vhostmd # systemctl status vhostmd ● vhostmd.service - LSB: Virtualization host metrics daemon Loaded: loaded (/etc/rc.d/init.d/vhostmd; bad; vendor preset: disabled) Active: active (running) since Tue 2017-06-27 10:32:07 CST; 47min ago Docs: man:systemd-sysv-generator(8) Process: 29477 ExecStop=/etc/rc.d/init.d/vhostmd stop (code=exited, status=0/SUCCESS) Process: 29489 ExecStart=/etc/rc.d/init.d/vhostmd start (code=exited, status=0/SUCCESS) CGroup: /system.slice/vhostmd.service └─29502 /usr/sbin/vhostmd --user vhostmd --connect qemu:///system Jun 27 11:10:20 localhost.localdomain vhostmd[29502]: Error writing metrics disk header sig: Permission denied Jun 27 11:11:20 localhost.localdomain vhostmd[29502]: Error writing metrics disk header sig: Permission denied ... Actual results: vhostmd having no permission to write metrics after attaching /dev/shm/vhostmd0 to the guest. Expected results: vhostmd should have permission to write metrics after attaching /dev/shm/vhostmd0 to the guest. Additional info: 1.See the error info in the syslog: #cat /var/log/messages ... Jun 27 11:20:40 localhost setroubleshoot: failed to retrieve rpm info for /dev/shm/vhostmd0 Jun 27 11:20:40 localhost setroubleshoot: SELinux is preventing /usr/sbin/vhostmd from write access on the file /dev/shm/vhostmd0. For complete SELinux messages run: sealert -l 9f9673b0-4e00-41f0-bb9e-ade129b66c28 Jun 27 11:20:40 localhost python: SELinux is preventing /usr/sbin/vhostmd from write access on the file /dev/shm/vhostmd0.#012#012***** Plugin catchall (100. confidence) suggests **************************#012#012If you believe that vhostmd should be allowed write access on the vhostmd0 file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vhostmd' --raw | audit2allow -M my-vhostmd#012# semodule -i my-vhostmd.pp#012 ...