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Re: SELinux last straw



> I leave you with this analogy...
> Your have a peddle bike with a loose chain.  You end up with a flat on
> the rear tire.  You remove the tire and replace the tube then replace
> the tire ensuring the chain is not loose.  You don't get any more flat
> tires.  You conclude "a loose chain causes a flat tire".  But in
> reality the chain was loose because the nuts on the rear tire were
> loose because someone tried to steal your tire but was interrupted -
> thus causing the tire to slip forward slightly.  This caused the tire
> to rub against a screw that was protruding (which was there to hold
> the new after market fender you installed on the rear tire so you
> wouldn't get mud splattered on your back when ridding the trails).
> This ultimately lead to a flat tire.  You repair the tire and replace
> it, tightening the chain in the process by pulling the rear tire back
> to its proper position.  Unknown to you the screw no longer rubs
> against the tire and the nuts are now tight thus the tire won't slip
> forward so no more flat tires.  You conclude that a loose chain is
> what caused your flat tire.  Next time someone complains of a flat
> tire you tell them it MUST be because of a loose chain.
>
> Jacques B.
>

The problem continues....
Later on your bike is running slow. It's difficult to peddle.  You
notice the loose chain again so you tighten it by resetting the rear
tire further back.  It corrects the problem.  Thus the loose chain
MUST be the problem of a slow bike.  And tightening it WILL fix it.

Later the symptom returns. Bike is slow again.  Worse, the rear tire
is showing damage. Finally the chain jumps off the sprocket causing
the bike to totally lock up crashing into the pavement. That damm
loose chain!

Meanwhile what really happened is that one of the rear bolts was
partially stripped when someone tried to steal your bike.  So that
side of the rear tire started easing forward causing the rim to rub
against the brake pad - thus slowing the bike.  It eases forward a bit
more because the bolt is still loose.  The tire starts rubbing against
that same screw again thus damaging the tire.  It eases forward yet
some more to the point that the chain is so loose it jumps off the
sprocket.  The rest is history.  That cursed loose chain.  It causes
flat tires, it slows the bike down, and it causes it to crash and
burn.

You see, that loose chain is mearly a domino effect symptom of the
root cause of the problem, that stripped bolt. Which in turn was
caused by the guy who tried to steal your bike.  And the tire damage
is caused by that fender you installed using a screw that was too
long, but only after the damaged screw (root cause) starts slipping.
Fix that bolt (replace it) and you've corrected all the problems that
you thought were caused by that "cursed loose chain".

A Linux system is significantly more complexe than a bike.  Potential
for a domino effect impacting SELinux certainly exists.  SELinux may
APPEAR to be the root cause of all your problems.  But it may only be
part of a chain reaction rooted somewhere else on your system.
SELinux may not be the cause, but perhaps the messenger, the visual
cue, the "chain" that you've now developed tunnel vision for and blame
for everything.

Jacques B.


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