Subject: Re: [Patch 0/2] powerpc: avoid userspace poking to legacy ioports
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reply-To: benh@kernel.crashing.org
To: Jean Delvare <khali@linux-fr.org>
Cc: Christian Krafft <krafft@de.ibm.com>, linux-kernel@vger.kernel.org,
       parabelboi@bopserverein.de, linuxppc-dev@ozlabs.org
In-Reply-To: <20080218211519.2b159ade@hyperion.delvare>
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	 <20080213183506.7f3e3145@de.ibm.com> <1202935374.7296.44.camel@pasglop>
	 <20080218211519.2b159ade@hyperion.delvare>
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Date: Tue, 19 Feb 2008 07:42:03 +1100
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> Maybe Christian's patch can be improved to not do the check on these?
> As long as /dev/port exists, it seems reasonable that the kernel should
> behave, no matter what I/O ports are accessed from user-space.

nonsense.

 /dev/mem exists for example, but you are still not supposed to go
bang all over the place in it.

> > I hate that sensors_detect.. or for that matter any other userland code
> > that pokes random ports like that. It should die.
> 
> What do you propose as a replacement?

Dunno, something less scary, like knowing where your sensors are on a
given machine... honestly, it's just scary the risk you guys are taking
by banging random IO ports.

At the very least, that shouldn't be done on non-x86.

> And how is userland code poking at random ports different from kernel
> code poking at random ports? We could move sensors-detect inside the
> kernel (and I have some plan to do that) but I fail to see how this
> would solve this particular problem.

It wouldn't, but at least I could NAK it or make it CONFIG_X86 :-)

Ben.


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