Bug 740702

Summary:	update floppy disk on the fly with <readonly/> failed when selinux is enforcing
Product:	Red Hat Enterprise Linux 6	Reporter:	weizhang <weizhan>
Component:	libvirt	Assignee:	Laine Stump <laine>
Status:	CLOSED WONTFIX	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	6.2	CC:	acathrow, dallan, dyuan, gsun, mzhan, rwu, ydu
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-11-23 18:57:33 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description weizhang 2011-09-23 02:37:59 UTC

Description of problem:
When selinux is enforcing, update floppy disk on the fly with <readonly/> failed with error
error: Failed to update device from floppy.xml
error: internal error unable to execute QEMU command 'change': Could not open '/var/lib/libvirt/images/fd2.img'

but when selinux is permissive, update-device will success

Version-Release number of selected component (if applicable):
kernel-2.6.32-197.el6.x86_64
qemu-kvm-0.12.1.2-2.192.el6.x86_64
libvirt-0.9.4-12.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Make 2 floppy disk image file

# dd if=/dev/zero of=/var/lib/libvirt/images/fd1.img count=1024 bs=1024

# mkfs.ext3 /var/lib/libvirt/images/fd1.img

# dd if=/dev/zero of=/var/lib/libvirt/images/fd1.img count=1024 bs=1024

# mkfs.ext3 /var/lib/libvirt/images/fd2.img

2. Define a domain with floppy device connected with in config xml file

    <disk type='file' device='floppy'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/fd1.img'/>
      <target dev='fda' bus='fdc'/>
      <readonly/>
    </disk>

3. Start the domain

4. Prepare a xml as flollowing:

# cat floppy.xml
    <disk type='file' device='floppy'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/fd2.img'/>
      <target dev='fda' bus='fdc'/>
      <readonly/>
    </disk>

5. Try to update the media int floppy device

# virsh update-device rhel6 floppy.xml
  
Actual results:
error: Failed to update device from floppy.xml
error: internal error unable to execute QEMU command 'change': Could not open '/var/lib/libvirt/images/fd2.img'

Expected results:
success with no error

Additional info:

Comment 4 Dave Allan 2011-11-23 18:57:33 UTC

A user can work around this problem by making the floppy writable by removing the readonly element from the XML.