Messages in this thread | | | Date | Tue, 10 Oct 2006 23:50:59 +0200 (CEST) | From | Paul Wouters <> | Subject | Re: more random device badness in 2.6.18 :( |
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On Tue, 10 Oct 2006, Michael Buesch wrote:
> > > Why should Openswan touch /dev/hw_random directly? > > > > Because using /dev/random whlie /dev/hw_random is available does not always > > work (eg with padlock) > > Oh, wait wait. I don't really understand your sentence. > Why can't you use /dev/random?
We have noticed in the past that on VIA's with the padlock, that /dev/random stopped working when hw_random got loaded, while we could get random from /dev/hw_random. So we assumed that was the design.
> /dev/hw_random should never be touched by anything else than rngd.
Seems like a good argument to keep this state hidden in the kernel then.
> rngd takes the data from /dev/hw_random, _verifys_ it and puts it into > the normal /dev/random pools. > The verification step is really important.
I understand the use of a FIPS compliant hardware random.
> So I would like to ask the other way around. Why should be put this code > into the kernel, while it works in userspace as good (or, some people may > argue it is even better in userspace, because it can more easily be exchanged, > debugged and configured. Whatever)
If only a single process should ever touch a device, I wonder why it is a device visible to all of userland. For one, it confuses stupid people like me. Second, it seems that perhaps the reason the VIA hardware random was "broken" was becaus I and others were unaware of the requirement of rngd with hw_random. I am obviously not the only one, since Fedora Core 6 test 3 autoloads the hardware random module, but does not come with the rng-tools package to fix /dev/random to actually use /dev/hw_random.
At least I do feel better now about all the device renames. rngd uses "hwrandom" per default, which no longer exists. Then there is hw_random, which seems to be something obsolete for hwrng judging by the softlink. And I can stop worrying that /dev/hw_random cannot be read without root permission on default modprobe. I'm happy to hear I no longer need to worry about all those devices, and I can go back and remove the code that deals with /dev/hw_random, after I verify that the VIA systems still have a functional /dev/random if someone modprobe's hw_random without running rngd. But if not running rngd breaks /dev/random, then we'll be forced to keep an eye out for those /dev/hw* devices.
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