[CentOS] selinux: how to allow access?

Tue Mar 20 12:07:12 UTC 2018
hw <hw at gc-24.de>

On 03/16/2018 10:38 PM, Phil Perry wrote:
> On 16/03/18 18:37, Alexander Dalloz wrote:
>> Am 16.03.2018 um 13:09 schrieb hw:
>>> On 03/16/2018 12:14 PM, Richard Grainger wrote:
>>>>> Yet again I could not find any documentation explaining how to do 
>>>>> basic
>>>>> things like this :(  Selinux is more like a curse than anything 
>>>>> else :( Why
>>>>> is there not even a good documentation?
>>>> More trolling?
>>> Show me a good documentation and/or name good reasons not to disable 
>>> selinux.  Considering how much trouble it gives, there have to be 
>>> *very* good reasons to keep it enabled.
> Would you turn off your firewall because you don't understand how it 
> works? Or any security feature for that matter?

That depends.  If the anti-theft system of your car prevents you from 
driving it, wouldn´t you turn it off so you can drive to work?

> Invest a few hours of your life reading the documentation. There are 
> plenty of good examples listed below.

You can´t read documentation when you can´t find it.

> I've never had an SELinux problem I couldn't solve or work around in 2 
> minutes. Sometimes figuring out the *right* solution might take a little 
> longer, but turning it off is very rarely going to be the right solution.

I don´t believe that.  First you need to figure out if it´s a selinux 
related thing, and to do that, you need to figure out how to figure that 
out.  Once you figured it out, you need to figure out how to solve it. 
That usually takes hours or even days.

>> Useful resources for SELinux:
>> http://wiki.centos.org/HowTos/SELinux
>> http://wiki.centos.org/TipsAndTricks/SelinuxBooleans
>> http://docs.fedoraproject.org/en-US/Fedora/13/html/Security-Enhanced_Linux/ 
>> http://www.youtube.com/watch?v=bQqX3RWn0Yw
>> http://opensource.com/business/13/11/selinux-policy-guide
> https://lists.centos.org/mailman/listinfo/centos

I´ve seen some of those, finding a hint here and there, but not a really 
good documentation yet.

> and don't forget the definitive Red Hat documentation here:
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/
> SELinux User's and Administrator's Guide at the bottom of the page. 
> Download it and read it.

That looks promising, though it seems to make quite a hype of it.  It 
even says wrong things, like: Mandatory access control "enables 
information to be protected from legitimate users with limited 
authorization as well as from authorized users who have unwittingly 
executed malicious applications."[1]  Perhaps there are implementations 
of MAC which do that; selinux does not.  It´s even a thing I´ve asked 
about quite a while ago, and there didn´t seem to be a way to achieve it 
with selinux.

So what do you really gain from selinux, and is that worthwhile all the 
trouble and the hours spent to fix the problems it creates?  What about 
the impact on performance?