question about process power which has MCSx

[Daniel J Walsh]

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On 04/17/2013 12:53 PM, Dominick Grift wrote:
> On Wed, 2013-04-17 at 23:18 +0800, bigclouds wrote:
>> a process can access a file , they   have  same MCS. the authority of
>> access the file is its biggest authority or smallest authority?
> 
> Not sure if i understand your question but the MCS range of the source 
> operating on the target needs to be exactly the same i believe
> 
>> can anythings else the process have access to, besides the file? thanks
>> 
> 
> Here are the MCS rules:
> 
> https://git.fedorahosted.org/cgit/selinux-policy.git/tree/policy/mcs
> 
> You can look there to see how mcs affects the policy
> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> At 2013-04-17 21:15:10,"Dominick Grift" <dominick.grift at gmail.com>
>> wrote:
>>> On Wed, 2013-04-17 at 17:49 +0800, bigclouds wrote:
>>>> hi,all a qemu-kvm process and its disk(image file) have the same 
>>>> MCS(s0:c111,c555). it express this process have access to this
>>>> image. i do not know the power to access its image file is the max or
>>>> min? if any other power this process(domain) has?how much? i want to
>>>> know the exact power a qemu-kvm process has besides access its image
>>>> file ,other kinds of files,dirs etc.
>>> 
>>> I do not fully understand your question and the information you
>>> provided does not clarify the issues for me but:
>>> 
>>> Here you can find the Fedora MCS rules:
>>> 
>>> https://git.fedorahosted.org/cgit/selinux-policy.git/tree/policy/mcs
>>> 
>>> To see what all types have assigned the mcs_contrained_type attribute:
>>> 
>>> seinfo -xamcs_constrained_type
>>> 
>>>> 
>>>> my test case: after start a guestVM(its disk xml ,cache='none'
>>>> error_policy='stop'), make some modification on its files and save
>>>> them. then go to hypervisor, modify the MCS of guestVM's image file. 
>>>> 1.i can read those files(cache=none)?it s hould not be so. why? 
>>>> 2.then modify files and save, the guestVM hang, it is paused on UI. 
>>>> this is right qeum process can not write again. why this guestVM is 
>>>> hang? and can not be resumed 3.look at audit info. denied { write }
>>>> for pid=52162 comm="qemu-kvm". that pid is 52162, is not my
>>>> qemu-kvm's pid? why?
>>>> 
>>>> thanks so much.
>>>> 
>>>> 
>>>> -- selinux mailing list selinux at lists.fedoraproject.org 
>>>> https://admin.fedoraproject.org/mailman/listinfo/selinux
>>> 
>>> 
>> 
>> 
> 
> 
> -- selinux mailing list selinux at lists.fedoraproject.org 
> https://admin.fedoraproject.org/mailman/listinfo/selinux
> 
Must be my day to blog.

http://danwalsh.livejournal.com/#post-danwalsh-63472

This blog explains MCS Separation.


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