Description of problem:

I do not understand just what and how sVirt is trying to protect resources by changing the fcontext for the CD/DVD iso image file (or /dev/sr0 for that matter).

Given that an iso file is globally read-only on a host, I do not see this context change does much .. non-root users (owners and non-owners) can still copy the iso image file.

This is very confusing ... I just do not understand what is being protected and from whom!

However, this "zeal" to change the file's context also causes a problem when I try to use an iso image on another system through a read-only nfs4 mount.

When I tried this, the virt-managers guest creation wizard dies with the following:

-----------------------------------
Unable to complete install '<class 'libvirt.libvirtError'> internal error Domain f11-64 didn't show up

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/create.py", line 1501, in do_install
    dom = guest.start_install(False, meter = meter)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 541, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 633, in _do_install
    self.domain = self.conn.createLinux(install_xml, 0)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 974, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Domain f11-64 didn't show up

'
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I also tried doing this by using a symbolic link in the /var/lib/libvirt/images directory which pointed to the read-only mounted nfs4 filesystem and the result was pretty much the same:

----------------------------------
Unable to complete install '<class 'libvirt.libvirtError'> internal error Domain f11-tst1 didn't show up

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/create.py", line 1501, in do_install
    dom = guest.start_install(False, meter = meter)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 541, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 633, in _do_install
    self.domain = self.conn.createLinux(install_xml, 0)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 974, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Domain f11-tst1 didn't show up

'
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Just because SELinux is there does not mean that it is an appropriate protection mechanism (and I am very much an SELinux fan!!)
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Version-Release number of selected component (if applicable):
libvirt-0.6.2-12.fc11.x86_64
selinux-policy-3.6.12-57.fc11.noarch (from updates-testing)