[CentOS] Fwd: Re: SELinux triggered during Libvirt snapshots
Daniel J Walsh
dwalsh at redhat.com
Mon Oct 17 15:30:43 UTC 2011
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On 10/17/2011 11:19 AM, Trey Dockendorf wrote:
> Forwarding back to list. ---------- Forwarded message ----------
> From: "Trey Dockendorf" <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>
>
>
>
> On Mon, Oct 17, 2011 at 7:47 AM, Daniel J Walsh <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
>>>> 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
> http://lists.centos.org/mailman/listinfo/centos
Did you add additional file systems?
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