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SELinux and Fedora

SELinux and Fedora

Posted Jul 10, 2008 2:47 UTC (Thu) by jmorris42 (guest, #2203)
Parent article: SELinux and Fedora

Somebody needs to inform Mr. Cox that when the automakers used his reasoning and turned on the
airbags with no option to turn them off a lot of people, mostly children and smaller women,
DIED.  That is why all new vehicles (at least in the US, perhaps the UK government prefers to
keep killing people in the name of political doctrine) have airbag kill switches for the
passenger seat.

So yes safety features do need to consider balance.  I know I tend to switch the damned thing
off after the first couple of failures, because in enforcing mode most machines are useless
and in permisive /var/log/messages is useless because of the noise.  Too much junk in the logs
can cause other problems to be missed.

SELinux is great if you are building a server running a locked down set of processes and your
use happens to actually run under SELinux with only a few rounds of the SELinux Troubleshooter
giving out incomprehensible incantations to say at a root terminal, reboot and try again.

I have been running Linux/UNIX/OS-9 since the freaking 80's and totally understand the UNIX
security model, but SELinux is so alien to UNIX thought  that I haven't a clue how to modify
it.  I even tried wading through the O'Reilly SELinux book and just didn't get it.  I suspect
that I'm not alone.

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Kill switch is there

Posted Jul 10, 2008 6:57 UTC (Thu) by khim (subscriber, #9252) [Link]

You can disable SELinux for postgresql or mysql or any other program - that's your "airbag kill switch for the passenger seat". The installer option is more like "do you want to remove all airbags from the car - forever?" and I know no automakers who offer such an option.

Kill switch is there

Posted Jul 10, 2008 14:45 UTC (Thu) by jebba (✭ supporter ✭, #4439) [Link]

> "Shall I enable the airbag ?"

If it prevents me from putting the car in gear, no thx.

Kill switch is there

Posted Jul 10, 2008 17:52 UTC (Thu) by JoeBuck (guest, #2330) [Link]

I've been running my machines at home with SELinux enabled for years. I've occasionally had a problem, but overall it's gone rather smoothly. About a year ago I needed to disable SELinux for about a day until the Fedora folks fixed a problem. I've learned enough about how the labels work that I can fix simple issues.

It doesn't prevent you from putting your car in gear.

And it's still easy to turn off from the command line. Users who are going to stick to the GUI can run with the policies Fedora ships, and they work.

Safety features

Posted Jul 10, 2008 12:05 UTC (Thu) by tialaramex (subscriber, #21167) [Link]

Actually most cars that I've seen simply have a sticker which says something like "Danger: Air
bag fitted:: Do not use rear-facing child seats" and the government produces pictographic
instructions which are mandatory for new child seats that show the best place to put them (in
the back of the car, it's amazing how many parents somehow can't figure that out) and how to
correctly fit them, plus the explicit warning about not using them in the front. There have
never been suitable restraints in the front of a car to have a baby or young child next to you
while driving, (hint: it will still be there when you arrive, and whatever it's screaming
about you won't be able to do anything about it while driving) so don't do it unless its an

It's true that US drivers love to disable safety features, often by removing the relevant fuse
or micro- circuit breaker. I'd assumed this was part of the same culture that causes them to
fight seat belt laws, drink drive laws etc. a sort of misplaced devil-may-care frontier thing.

As to SELinux, I haven't found it a large obstacle. My colleague on the other hand seems to
have no end of problems, I think it's about how you approach security problems. My approach
agrees with that of SELinux, whitelisting, safe-by-default, assume unknowns are bad etc. while
his is constantly in conflict with it, he'd rather blacklist things once he sees why they were
bad, and so on. He gets things done faster, but they break more often (and often in ways that
have potential security consequences).

I found out the other day that he hates the safety interlock delay on washing machines. I was
very happy when I found out about that delay as a teenager (doing my first load of washing and
of course reading the manual), it seemed like a sensible way to avoid potentially dangerous
interactions between operator and machine, but to him it's apparently a constant source of

Safety features

Posted Jul 13, 2008 10:16 UTC (Sun) by modernjazz (guest, #4185) [Link]

To both jmorris42 and tialaramex: can we please keep the cross-Atlantic 
sniping out of technical discussions? Accusing the British government of 
indirectly killing children for idealogical reasons is outrageous and 
inflammatory---in addition to being wrong and grossly unfair, the 
seriousness of that charge goes so far beyond what is needed to make the 
point that it derails the whole discussion.

Similarly, blaming an "American frontier mentality" for technical 
concerns about airbags that in fact do go well beyond babies in child 
seats is misinformed and reactionary. There are indeed circumstances 
where doing something to disable the airbag on your car is the best thing 
you can do for the safety of even young/small adults.

Safety features

Posted Jul 14, 2008 10:23 UTC (Mon) by paulj (subscriber, #341) [Link]

it's amazing how many parents somehow can't figure that out

Some parents may have 2 or 3 children who are too old for baby seats, but too young/small to be allowed to legally sit in front seat (least, without additional specialised seat restraint systems) and so, out of convenience or neccesity, must use the 2 or 3 rear seats, leaving the front seat as only option for baby seat..

Safety features

Posted Jul 21, 2008 12:12 UTC (Mon) by ekj (guest, #1524) [Link]

Except offcourse, if you've got multiple kids.

We've got 3. We've also got a reasonably small car. (It's not as if we -knew- we'd get twins,
ok ?)

End-result ? The only practical way of transporting the three of them to childcare is having
the older one infront next to me, and the smaller twins in the back. 

Offcourse a kill-switch for the passenger-airbag was a $75 fix, so it's not a big deal. Just
saying there -are- legitimate reasons for having a small child in front, sometimes.

OMG! Won't someone please think of the children?!

Posted Jul 10, 2008 12:58 UTC (Thu) by ofeeley (subscriber, #36105) [Link]

It's always possible to twist an analogy or metaphor out of shape in order to miss its intent. Further on in the discussion[1] Alan Cox likens the discussion of whether or not SELinux should be on by default to what used to be the controversial topic of enabling firewalls by default. A lot of people's work was complicated and interrupted by the addition of firewalls yet I doubt many would wish them to either be less commonly deployed or presented as a confusing choice to novice users at installation time.

The fact is that there IS a kill switch (to use your metaphor) for those that know what they're doing. No one is arguing that SELinux should be made impossible to disable, just that there should not be the equivalent of a button on the dashboard that says "Press to stop the irritating sound that indicates your airbags are malfunctioning. You may then continue on your merry way."

The article also misses out on mentioning the rapid, copious help that seems to emanate from Dan Walsh and the other SELinux devs with fixing policies when bugs are filed in bugzilla.

1. Fedora Weekly News #133 - SELinux Eats Babies, Confines Wives, Gives Birth

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