This avc is a constraint violation! Stuck resolving this via --update on sepolgen generated file

[Dominick Grift]

On Fri, 2011-09-23 at 13:46 +0200, Michael Atighetchi wrote:
> On 9/23/2011 1:21 PM, Dominick Grift wrote: 
> > On Fri, 2011-09-23 at 12:55 +0200, Michael Atighetchi wrote:
> > > Hi,
> > > 
> > > I am stuck trying to create a selinux policy for the Software Test 
> > > Automation Framework (STAF) daemon on Fedora 14.
> > >  From the violations, it seems that STAF wants to send out emails and 
> > > restart iptables, which is behavior that should be allowed.
> > > 
> > > I've created the inital policy with sepolgen and did run the resulting 
> > > .sh script with "--update" a number of times, but so far no success in 
> > > getting a policy that works without generating violations.
> > > 
> > > I have included the resulting te file as an attachment.
> > You have made a mistake. When writing policy one should always try and
> > take care of any transitions first.
> > 
> > Your policy allows your stafproc_t process to execute iptables but this
> > is wrong i suspect. I suspect you added that because stafproc_t needs to
> > restart the iptables service. (this requires a domain transition to the
> > init script domain. The iptables init script file running in the init
> > script domain will execute iptables with a domain transition.
> > 
> > You added a lot of policy in your type enforcement file that likely
> > should not be there. Just because you did not take care of this
> > transition described above before allowing anything else.
> > 
> > If you want some interactive guidance with your policy, please stop by
> > #fedora-selinux on irc.freenode.net
> Dominick,
> 
> thanks for the fast response. I'll add the transition you suggested in
> the other email and start over with a small type enforcement file.
> What I was trying to do is to use sepolgen to generate a minimalistic
> policy, then run the processes through its paces and add
> observed violations via --update. 
> Regarding transitions, is there a way to programmatically figure out
> what transitions a process might need or do you have to know something
> about the processes to construct required transitions ?
> I will gladly take you up on the interactive guidance early next week.

To some degree, maybe, but it is not easy if it is possible.

One must keep in mind that SELinux is a framework and policy is not
something that is fixed. So you can not use policy as something fixed in
a program if you want this program to be proper.

A type may exist and have a particular classification in one policy and
not exist in another policy.

A program can not make security decisions generally.

This is also why i do not believe that polgen is and should be real
solution.

That is not to say that there cannot be programs that make policy
writing easier. Tools like Eclipse-slide can help, regardless of the
policy -- as long as it is based off of reference policy ;)

> Thanks and have a great weekend 
> Michael
> 
> 
> > > Any ideas about what could be wrong would be greatly appreciated.
> > > 
> > > The current set of violations are:
> > > [root at lime audit]# grep AVC audit.log  | grep STAF
> > > type=AVC msg=audit(1316772648.834:16749): avc:  denied  { create } for  
> > > pid=13504 comm="STAFProc" name="STAF.tmp" 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=unconfined_u:object_r:krb5_host_rcache_t:s0 tclass=file
> > > type=AVC msg=audit(1316772676.905:16750): avc:  denied  { read } for  
> > > pid=13541 comm="killall" name="stat" dev=proc ino=5874476 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=system_u:system_r:sendmail_t:s0 tclass=file
> > > type=AVC msg=audit(1316772676.905:16750): avc:  denied  { open } for  
> > > pid=13541 comm="killall" name="stat" dev=proc ino=5874476 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=system_u:system_r:sendmail_t:s0 tclass=file
> > > type=AVC msg=audit(1316772676.906:16751): avc:  denied  { getattr } for  
> > > pid=13541 comm="killall" path="/proc/1433/stat" dev=proc ino=5874476 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=system_u:system_r:sendmail_t:s0 tclass=file
> > > type=AVC msg=audit(1316772677.136:16755): avc:  denied  { transition } 
> > > for  pid=13558 comm="env" path="/etc/rc.d/init.d/iptables" dev=dm-0 
> > > ino=652904 scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=unconfined_u:system_r:STAFProc_t:s0 tclass=process
> > > type=AVC msg=audit(1316772677.136:16755): avc:  denied  { rlimitinh } 
> > > for  pid=13558 comm="iptables" 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=unconfined_u:system_r:STAFProc_t:s0 tclass=process
> > > type=AVC msg=audit(1316772677.136:16755): avc:  denied  { siginh } for  
> > > pid=13558 comm="iptables" 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=unconfined_u:system_r:STAFProc_t:s0 tclass=process
> > > type=AVC msg=audit(1316772677.136:16755): avc:  denied  { noatsecure } 
> > > for  pid=13558 comm="iptables" 
> > > scontext=unconfined_u:unconfined_r:STAFProc_t:s0 
> > > tcontext=unconfined_u:system_r:STAFProc_t:s0 tclass=process
> > > 
> > > 
> > > 
> > > 
> > > --
> > > 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
> 
> 
> -- 
> Michael Atighetchi
> Senior Scientist
> Raytheon BBN Technologies
> 617-873-1679
> matighet at bbn.com

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