Making Fedora a contributer friendly environment

Karl MacMillan kmacmill at
Thu May 10 15:49:20 UTC 2007

[CC'd the selinux development list so that the developers are aware of
these issues]

On Thu, 2007-05-10 at 16:50 +0200, Till Maas wrote:
> On Do Mai 10 2007, Karl MacMillan wrote:
> > When selinux is turned on again a full relabel of the filesystem is done
> > to correct these problems. If the custom file context wasn't added to
> > the database of file contexts (via a module or semanage) the file is set
> > to the default label.
> So will chcon in a scriptlet work, when an rpm is installed while selinux is 
> not active?

Unfortunately it won't - does semanage / semodule work in this instance
(it probably should so that users can turn selinux back on after
disabling and doing package management).

> > Not sure what you mean - you should be able to run semanage in a post.
> > Perhaps you should also need to do chcon (as opposed to restorecon)
> > because the command may not have run before the file was created.
> When I tested semanage, the problem occured, how to update the labels with 
> semanage. E.g. when the regex is changed that desribes, which files should be 
> labeled in a certain way. And when one wants to remove the old labels when 
> uninstalling the package. E.g
> version 1 of the package:
> %post
> semanage add RULE1
> %postun
> semanage remove RULE1
> As far as I understand rpm, when updating the release of version 1, first 
> semanage add RULE1 from release two runs from %post and then
> semanage remove RULE1 from release one. This effectivly removes the rule from 
> the /etc/selinux, because identical rules seem not be added more than once 
> to /etc/selinux. When I restrict the %postun only to complete removals of the 
> package,

Which seems like the right answer.

>  than when one changes the RULES, e.g. in a version 2:
> %post 
> semanage add RULE2
> %postun
> semanage remove RULE2
> then RULE1 will not be removed (it is not the final remove). Then every 
> release has to include "semanage remove RULE1" in "%post" maybe forever. I 
> hope you understand the problem I try to describe, because I did not really 
> use the correct selinux-terms.

Seems like there are two cases:

1) The context changes but the file spec stays the same - blindly adding
should always work here (it will overwrite the old file context).

2) The file spec changes (doesn't matter if the context changes) - you
will have to carry around the removal in the post forever.

> I would be happy, if I am wrong with this. But if this problem is not solvable 
> with semanage, imho semanage is not a good way to add selinux support to a 
> package.

Maybe - we can make changes as necessary to make it usable.


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