From: dwalsh@redhat.com (Daniel J Walsh)
Date: Mon, 07 Jun 2010 11:52:40 -0400
Subject: [refpolicy] kernel_devices.patch
In-Reply-To: <1275917955.809.93.camel@gorn.columbia.tresys.com>
References: <4C06BCD3.5020900@redhat.com>	
	<1275916842.809.90.camel@gorn.columbia.tresys.com>	
	<4C0CF2EF.4090909@redhat.com>
	<1275917955.809.93.camel@gorn.columbia.tresys.com>
Message-ID: <4C0D15C8.4020006@redhat.com>
To: refpolicy@oss.tresys.com
List-Id: refpolicy.oss.tresys.com

On 06/07/2010 09:39 AM, Christopher J. PeBenito wrote:
> On Mon, 2010-06-07 at 09:23 -0400, Daniel J Walsh wrote:
>> On 06/07/2010 09:20 AM, Christopher J. PeBenito wrote:
>>> On Wed, 2010-06-02 at 16:19 -0400, Daniel J Walsh wrote:
>>>> http://people.fedoraproject.org/~dwalsh/SELinux/F14/kernel_devices.patch
>>>>
>>>> Added default label for /sys so libvirt could relabel to it.
>>>
>>> I don't understand this.  There should be no files labeled sysfs_t,
>>> except for the entries created by the kernel on the fs itself, which get
>>> the right label already.
>>>
>> libvirt currently does the equivalent of
>>
>> chcon svirt_t:MCS1 DEVICE
>> Run QEMU
>> restorecon DEVICE
>>
>> If /sys is<<none>>  then it does not have a label to change the context
>> back to.  And leaves the context with a label svirt_t:MCS1.  If it later
>> picks an svirt_t:MCS1 for a different image, this /sys device is vulnerable.
>
> I still don't understand.  There are no device nodes in sysfs.
>
sysfs supports labeling now.  Certain objects need to have a 
svirt_image_t:MCS label associated with them under /sys (Usb devices?) 
When libvirt needs to changes these labels back to the default it asks 
matchpathcon and it returns sysfs_t.