fs_use_xattr question

fs_use_xattr question

[Dan Noland]

- Hello -

I have a custom stacked filesystem and I was having difficulty with
security xattrs. I traced it back to missing:  

fs_use_xattr myfs gen_context(system_u:object_r:fs_t,s0);

Which works nicely when I rebuild/reinstall the base policy. However
some experimentation and checking of old mailing posts seems to
indicate that it is not possible to achieve this in a policy module. 

Because my FS is stacked I would be perfectly happy just to
inherit whatever the fs_use_xattr state of my lower filesystem is.

Is there a best practice for achieving this or do I need to always
rebuild the base policy?

Thank you for your time.

-- 
TY,
Dan Noland

Re: fs_use_xattr question

[Dominick Grift]

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On Fri, Jun 14, 2019 at 10:01:52PM +0000, Dan Noland wrote:
> - Hello -
> 
> I have a custom stacked filesystem and I was having difficulty with
> security xattrs. I traced it back to missing:  
> 
> fs_use_xattr myfs gen_context(system_u:object_r:fs_t,s0);
> 
> Which works nicely when I rebuild/reinstall the base policy. However
> some experimentation and checking of old mailing posts seems to
> indicate that it is not possible to achieve this in a policy module. 
> 
> Because my FS is stacked I would be perfectly happy just to
> inherit whatever the fs_use_xattr state of my lower filesystem is.
> 
> Is there a best practice for achieving this or do I need to always
> rebuild the base policy?

If you are able to use CIL then you might be able to do this:

echo '(fsuse xattr "myfs" (system_u object_r fs_t ((s0)(s0))))' > mytest.cil && sudo semodule -i mytest.cil

> 
> Thank you for your time.
> 
> -- 
> TY,
> Dan Noland

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Dominick Grift

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