Bug 1151819

Summary: Vdsm images use less secure selinux label after a lv is refreshed
Product: Red Hat Enterprise Virtualization Manager Reporter: Tal Nisan <tnisan>
Component: vdsmAssignee: Nir Soffer <nsoffer>
Status: CLOSED CURRENTRELEASE QA Contact: Aharon Canan <acanan>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 3.5.0CC: acanan, amureini, bazulay, ebenahar, ecohen, fsimonce, gklein, iheim, lpeer, lsurette, mgoldboi, nsoffer, ogofen, rbalakri, scohen, sherold, tnisan, yeylon
Target Milestone: ---Keywords: ZStream
Target Release: 3.5.0   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: storage
Fixed In Version: vdsm-4.16.7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 1149883
: 1152647 (view as bug list) Environment:
Last Closed: 2015-02-16 13:38:48 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: Storage RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1149883    
Bug Blocks: 1073943, 1152647, 1156162    
Attachments:
Description Flags
Logs01
none
/usr/lib/udev/rules.d/12-vdsm-lvm.rules none

Description Tal Nisan 2014-10-12 08:20:02 UTC 
+++ This bug was initially created as a clone of Bug #1149883 +++

Description of problem:

In Ovirt-3.5.0 on EL7 or Fedora, vdsm logical volumes are using
less secure selinux label compared with EL6.

When libvirt starts a vm, it apply "svirt_image_t:s0:cX,cY"
(where X and Y are unique per vm) to writable images, and
"virt_content_t" to readonly images. This separates virtual
machines from each other, preventing compromised qemu process
from writing into image belonging to another virtual machine.

When a volume becomes full, vdsm extends and refreshes the
volume. This causes a udev change event, which apply the static
selinux label "svirt_image_t", for both writable images and
readonly images.

The static selinux label is a temporary fix for bug 1127460. 
Without this fix, vms would pause after extend, making thin 
provisioning on block storage unusable.

The root cause is that udev changed the semantics of the udev
rules in Fedora 19 and later, as described in bug 1147910. 
We do not expect to get a fix from udev.


Steps to reproduce - leaf volume:

1. Create and start a vm with one thin provision disk
2. Find the storage domain id and disk lv name in vdsm log
3. Check the selinux label of the lv:
   ls -Z `realpath /dev/vgname/lvname`
4. Perform enough io so the disk would be extended (e.g. install os)
5. Check the selinux label of the lv again

Actual results:
Lv is using "svirt_image_t:s0" static label

Expected results:
Lv must use svirt_image_t:s0:cX,cY


Steps to reproduce - internal volume:

1. Create and start a vm with one thin provision disk and one snapshot
2. Find the storage domain id and disk lv name of the base volume in vdsm log
3. Check the selinux label of the lv:
   ls -Z `realpath /dev/vgname/lvname`
4. Refresh the lv
   lvchange --refresh --config "global {use_lvmetad=0}" vgname/lvname
5. Check the selinux label of the lv again

Actual results:
Lv is using "svirt_image_t:s0" static label

Expected results:
Lv must use "virt_content_t:s0"

--- Additional comment from Nir Soffer on 2014-10-06 18:24:34 EDT ---

The attached patch is required but does not fix this issue.

--- Additional comment from Nir Soffer on 2014-10-08 09:05:37 EDT ---

http://gerrit.ovirt.org/33874 is not required for this fix now. It will be available in the next version.
Comment 1 Scott Herold 2014-10-14 07:33:53 UTC 
Missed cutoff for 3.4.3.  Moving to 3.4.4 due to:

1) RHEL 7 is only Tech Preview on 3.4, so bug is non-urgent
2) Current gerrit commit is a temporary fix
3) We cannot delay the release of 3.4.3 at this point in time
Comment 2 Nir Soffer 2014-10-14 15:17:32 UTC 
(In reply to Scott Herold from comment #1)
> Missed cutoff for 3.4.3.  Moving to 3.4.4 due to:
> 
> 2) Current gerrit commit is a temporary fix

It is not temporary fix, this is the real fix. We are not expecting any other fix from platform or plan any other change.

If we have time to do a rebuild, there is no problem to include this fix.
Comment 4 Aharon Canan 2014-10-30 12:29:02 UTC 
reproduced using vt8 over rhel7 host.

leaf volume before extend -
=========================== 
[root@blond-vdsf ~]# ls -Z `realpath /dev/e96df368-09d6-4c9e-ba6d-fd09f09edcbc/8fd3ef93-afa3-4a23-b468-0b0345f453c1`
brw-rw----. vdsm qemu system_u:object_r:svirt_image_t:s0:c43,c1008 /dev/dm-15

leaf volume after extend - 
==========================
[root@blond-vdsf ~]# ls -Z `realpath /dev/e96df368-09d6-4c9e-ba6d-fd09f09edcbc/8fd3ef93-afa3-4a23-b468-0b0345f453c1`
brw-rw----. vdsm qemu system_u:object_r:fixed_disk_device_t:s0 /dev/dm-15
Comment 5 Aharon Canan 2014-10-30 12:30:31 UTC 
Created attachment 952089 [details]
Logs01
Comment 6 Nir Soffer 2014-10-30 13:14:25 UTC 
(In reply to Aharon Canan from comment #4)
> reproduced using vt8 over rhel7 host.

Please attach /usr/lib/udev/rules.d/12-vdsm-lvm.rules.
Comment 7 Aharon Canan 2014-10-30 13:19:29 UTC 
Created attachment 952114 [details]
/usr/lib/udev/rules.d/12-vdsm-lvm.rules
Comment 8 Nir Soffer 2014-10-30 13:23:46 UTC 
(In reply to Aharon Canan from comment #7)
> Created attachment 952114 [details]
> /usr/lib/udev/rules.d/12-vdsm-lvm.rules

This file does not include the fix - are you sure that vt8 is installed on this machine?
Comment 9 Aharon Canan 2014-10-30 13:47:40 UTC 
You are right, used the wrong cluster in the setup by mistake.

Verified using vt8 over rhel7