[CentOS] Fwd: Re: SELinux triggered during Libvirt snapshots

Mon Oct 17 19:40:31 UTC 2011
Trey Dockendorf <treydock at gmail.com>

On Oct 17, 2011 2:06 PM, "Daniel J Walsh" <dwalsh at redhat.com> wrote:
>
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> On 10/17/2011 02:09 PM, Trey Dockendorf wrote:
> > On Oct 17, 2011 10:30 AM, "Daniel J Walsh" <dwalsh at redhat.com
> > <mailto:dwalsh at redhat.com>> wrote:
> >>
> > On 10/17/2011 11:19 AM, Trey Dockendorf wrote:
> >> Forwarding back to list. ---------- Forwarded message ----------
> >> From: "Trey Dockendorf" <treydock at gmail.com
> >> <mailto:treydock at gmail.com>> Date: Oct 17, 2011 10:06 AM Subject:
> >> Re: [CentOS] SELinux triggered during Libvirt snapshots To:
> >> "Daniel J Walsh" <dwalsh at redhat.com <mailto:dwalsh at redhat.com>>
> >
> >
> >
> >> On Mon, Oct 17, 2011 at 7:47 AM, Daniel J Walsh
> >> <dwalsh at redhat.com <mailto:dwalsh at redhat.com>> wrote:
> >
> >> On 10/14/2011 08:17 PM, Trey Dockendorf wrote:
> >>>>> I recently began getting periodic emails from SEalert that
> >>>>> SELinux is preventing /usr/libexec/qemu-kvm "getattr"
> >>>>> access from the directory I store all my virtual machines
> >>>>> for KVM.
> >>>>>
> >>>>> All VMs are stored under /vmstore , which is it's own
> >>>>> mount point, and every file and folder under /vmstore
> >>>>> currently has the correct context that was set by doing the
> >>>>> following:
> >>>>>
> >>>>> semanage fcontext -a -t virt_image_t "/vmstore(/.*)?"
> >>>>> restorecon -R /vmstore
> >>>>>
> >>>>> So far I've noticed then when taking snapshots and also
> >>>>> when using virsh to make changes to a domain's XML file.
> >>>>> I haven't had any problems for the 3 or 4 months I've run
> >>>>> this KVM server using SELinux on Enforcing, and so I'm not
> >>>>> really sure what information is helpful to debug this.  The
> >>>>> server is CentOS 6 x86_64 updated to CR.  This is the raw
> >>>>> audit entry, (hostname removed)
> >>>>>
> >>>>> node=kvmhost.tld type=AVC msg=audit(1318634450.285:28):
> >>>>> avc: denied { getattr } for pid=1842 comm="qemu-kvm"
> >>>>> name="/" dev=dm-2 ino=2
> >>>>> scontext=system_u:system_r:svirt_t:s0:c772,c779
> >>>>> tcontext=system_u:object_r:fs_t:s0 tclass=filesystem
> >>>>> node=kvmhost.tld type=SYSCALL
> >>>>> msg=audit(1318634450.285:28): arch=c000003e syscall=138
> >>>>> success=no exit=-13 a0=9 a1=7fff1cf153f0 a2=0
> >>>>> a3=7fff1cf15170 items=0 ppid=1 pid=1842 auid=4294967295
> >>>>> uid=107 gid=107 euid=107 suid=107 fsuid=107 egid=107
> >>>>> sgid=107 fsgid=107 tty=(none) ses=4294967295
> >>>>> comm="qemu-kvm" exe="/usr/libexec/qemu-kvm"
> >>>>> subj=system_u:system_r:svirt_t:s0:c772,c779 key=(null)
> >>>>>
> >>>>> I've attached the alert email as a quote below, (hostname
> >>>>> removed)
> >>>>>
> >>>>> Any help is greatly appreciated, I've had to deal little
> >>>>> with SELinux fortunately, but at the moment am not really
> >>>>> sure if my snapshots are actually functional or if this is
> >>>>> just some false positive.
> >>>>>
> >>>>> Thanks - Trey
> >>>>>
> >>>>> Summary
> >>>>>>
> >>>>>> SELinux is preventing /usr/libexec/qemu-kvm "getattr"
> >>>>>> access on /vmstore.
> >>>>>>
> >>>>>> Detailed Description
> >>>>>>
> >>>>>> SELinux denied access requested by qemu-kvm. It is not
> >>>>>> expected that this
> >>>>>>> access is required by qemu-kvm and this access may
> >>>>>>> signal an intrusion attempt. It is also possible that
> >>>>>>> the specific version or configuration of the
> >>>>>>> application is causing it to require additional
> >>>>>>> access.
> >>>>>>
> >>>>>> Allowing Access
> >>>>>>
> >>>>>> You can generate a local policy module to allow this
> >>>>>> access - see FAQ
> >>>>>>> Please file a bug report.
> >>>>>>
> >>>>>> Additional Information
> >>>>>>
> >>>>>> Source Context:   system_u:system_r:svirt_t:s0:c772,c779
> >>>>>>
> >>>>>> Target Context:   system_u:object_r:fs_t:s0
> >>>>>>
> >>>>>> Target Objects:   /vmstore [ filesystem ]
> >>>>>>
> >>>>>> Source:   qemu-kvm
> >>>>>>
> >>>>>> Source Path:   /usr/libexec/qemu-kvm
> >>>>>>
> >>>>>> Port:   <Unknown>
> >>>>>>
> >>>>>> Host:   kvmhost.tld
> >>>>>>
> >>>>>> Source RPM Packages:   qemu-kvm-0.12.1.2-2.160.el6_1.8
> >>>>>>
> >>>>>> Target RPM Packages:
> >>>>>>
> >>>>>> Policy RPM:   selinux-policy-3.7.19-93.el6_1.7
> >>>>>>
> >>>>>> Selinux Enabled:   True
> >>>>>>
> >>>>>> Policy Type:   targeted
> >>>>>>
> >>>>>> Enforcing Mode:   Enforcing
> >>>>>>
> >>>>>> Plugin Name:   catchall
> >>>>>>
> >>>>>> Host Name:   kvmhost.tld
> >>>>>>
> >>>>>> Platform:   Linux kvmhost.tld 2.6.32-71.29.1.el6.x86_64
> >>>>>> #1 SMP Mon Jun 27
> >>>>>>> 19:49:27 BST 2011 x86_64 x86_64
> >>>>>>
> >>>>>> Alert Count:   1
> >>>>>>
> >>>>>> First Seen:   Fri Oct 14 18:20:50 2011
> >>>>>>
> >>>>>> Last Seen:   Fri Oct 14 18:20:50 2011
> >>>>>>
> >>>>>> Local ID:   c73c7440-06ee-4611-80ac-712207ef9aa6
> >>>>>>
> >>>>>> Line Numbers:
> >>>>>>
> >>>>>> Raw Audit Messages :
> >>>>>>
> >>>>>>
> >>>>>>> node=kvmhost.tld type=AVC
> >>>>>>> msg=audit(1318634450.285:28): avc: denied { getattr }
> >>>>>>> for pid=1842 comm="qemu-kvm" name="/" dev=dm-2 ino=2
> >>>>>>> scontext=system_u:system_r:svirt_t:s0:c772,c779
> >>>>>>> tcontext=system_u:object_r:fs_t:s0 tclass=filesystem
> >>>>>>
> >>>>>> node=kvmhost.tld type=SYSCALL
> >>>>>> msg=audit(1318634450.285:28): arch=c000003e
> >>>>>>> syscall=138 success=no exit=-13 a0=9 a1=7fff1cf153f0
> >>>>>>> a2=0 a3=7fff1cf15170 items=0 ppid=1 pid=1842
> >>>>>>> auid=4294967295 uid=107 gid=107 euid=107 suid=107
> >>>>>>> fsuid=107 egid=107 sgid=107 fsgid=107 tty=(none)
> >>>>>>> ses=4294967295 comm="qemu-kvm"
> >>>>>>> exe="/usr/libexec/qemu-kvm"
> >>>>>>> subj=system_u:system_r:svirt_t:s0:c772,c779 key=(null)
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> _______________________________________________ CentOS
> >>>>> mailing list CentOS at centos.org <mailto:CentOS at centos.org>
> >>>>> http://lists.centos.org/mailman/listinfo/centos
> >
> >
> >> THis is a bug in policy.  It can be allowed for now.
> >
> >> We have 6.2 selinux-policy preview package available on
> >> http://people.redhat.com/dwalsh/SELinux/RHEL6
> >
> >> I believe all that is happening is qemu-kvm is noticing you have
> >> a file system mounted, and doing a getattr on it.
> >
> >
> >> Thanks for the help Dan.  Is there something that could have
> >> triggered this between 6.0 and 6.1?  This server was updated to
> >> 6.0 CR around the same time this began happening, so I want to
> >> make sure if it's an issue in CR that I can file a useful bug
> >> report.
> >
> >> When updating selinux-policy, do I have to update all the RPMs
> >> listed or will that one package suffice?
> >
> >> Thanks - Trey _______________________________________________
> >> CentOS mailing list CentOS at centos.org <mailto:CentOS at centos.org>
> >> http://lists.centos.org/mailman/listinfo/centos
> >
> > Did you add additional file systems?
> >
> > Not after the upgrade.  The same filesystems were in place using
> > 6.0 and 6.0 CR.  The only change was the upgrade to CR.
> >
> > - Trey
> >
>
> Well I have no idea.  Anyways it is not a problem allowing this access.
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What do I have to do to allow that access?  Or should I update to the
selinux-policy you linked ?  Ive had little in the way of experience with
selinux so this is all new.

Thanks
- Trey