[libvirt] Live attaching a disk to a VM fails with apparmor enabled

[Guido Günther]

On Thu, Mar 30, 2017 at 03:00:06PM +0000, Frank Schreuder wrote:
> Hello Guido,
> 
> I have great news. I'm able to successfully live attach a disk to a running VM with a loaded apparmor profile.
> 
> My setup:
> Debian 8
> Kernel 4.9.11
> Libvirt 3.1.0
> Apparmor 2.10 from Debian backports
> 
> With same software and apparmor 2.9 from the stable Debian repo it fails. So apparently 2.10 has upstream fixes/patches which solve the reload profile bug? Hope this new insight helps you find the commit and backport it to apparmor 2.9 stable?

Thanks for reporting, I added a note to #805002. It's unlikely we'll
have a backport of both the kernel changes and appamor for Jessie but we
can make things work for stretch (which currently shows a different
error I'll have to look into).
Cheers,
 -- Guido

> 
> Thanks,
> Frank
> 
> 
> Sent from my iPhone
> 
> > On 24 Mar 2017, at 09:17, Guido Günther <agx at sigxcpu.org> wrote:
> > 
> >> On Thu, Mar 23, 2017 at 01:28:57PM +0100, Cedric Bosdonnat wrote:
> >> Hello Frank,
> >> 
> >> I'm currently investigating some apparmor-related bug with namespaces. This one
> >> is surely related. I'll look into it when I'm done with the one I'm working on.
> > 
> > Assuming you're running the Jessie Kernel its likely:
> > 
> >    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=805002
> > 
> > To make sure it's the kernel and not libvirt have a look at:
> > 
> >    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=805002#51
> > 
> > Cheers,
> > -- Guido
> > 
> >> 
> >> --
> >> Cedric
> >> 
> >>> On Thu, 2017-03-23 at 12:07 +0000, Frank Schreuder wrote:
> >>> Hello,
> >>> 
> >>> I'm running libvirt 3.1.0 on a Debian 8 server. I installed apparmor and configured libvirt to use apparmor as
> >>> security driver.
> >>> After booting a VM, virsh dumpxml shows an apparmor seclabel.
> >>> 
> >>> As soon as I try to attach a second disk to the VM, apparmor blocks this.
> >>> 
> >>> virsh attach-device test-vps /tmp/virshXmlDefinition
> >>> error: Failed to attach device from /tmp/virshXmlDefinition
> >>> error: operation failed: Could not open '/mnt/images/disk2.raw': Permission denied
> >>> 
> >>> Syslogs shows me the following:
> >>> Mar 22 17:45:20 vps0 kernel: [1136647.318314] audit: type=1400 audit(1490201120.577:30): apparmor="DENIED"
> >>> operation="open" profile="libvirt-5747e4db-a3b7-fd69-ca89-00007b0bf859" name="/mnt/images/disk2.raw" pid=13453
> >>> comm="kvm" requested_mask="r" denied_mask="r" fsuid=996 ouid=33
> >>> Mar 22 17:45:20 vps0 kernel: [1136647.325155] audit: type=1400 audit(1490201120.577:31): apparmor="DENIED"
> >>> operation="open" profile="libvirt-5747e4db-a3b7-fd69-ca89-00007b0bf859" name="/mnt/images/disk2.raw" pid=13453
> >>> comm="kvm" requested_mask="rw" denied_mask="rw" fsuid=996 ouid=33
> >>> Mar 22 17:45:20 vps0 libvirtd[10282]: 2017-03-22 16:45:20.596+0000: 10283: error : qemuMonitorTextAddDrive:1968 :
> >>> operation failed: Could not open '/mnt/images/disk2.raw': Permission denied
> >>> 
> >>> In the VM specific apparmor file /etc/apparmor.d/libvirt/libvirt-5747e4db-a3b7-fd69-ca89-00007b0bf859.files I see:
> >>> "/mnt/images/disk1.raw" rw,
> >>> 
> >>> Which is my primary VM disk, I expected a virsh attach-device to append /mnt/images/disk2.raw to this file and
> >>> reload/refresh the apparmor profile?
> >>> 
> >>> I'm not able to attach a live disk to a running VM with apparmor. Am I missing something? Or is this a bug/missing
> >>> feature in libvirt?
> >>> 
> >>> Thanks,
> >>> Frank
> >>> --
> >>> libvir-list mailing list
> >>> libvir-list at redhat.com
> >>> https://www.redhat.com/mailman/listinfo/libvir-list
> >> 
> >> --
> >> libvir-list mailing list
> >> libvir-list at redhat.com
> >> https://www.redhat.com/mailman/listinfo/libvir-list
> >>