Re: [PATCH] rand.c updates from FreeBSD RELENG_5
Kris Kennaway wrote:
> On 2004-05-13, Kris Kennaway <kkenn@xor.obsecurity.org> wrote:
>
>>On 2004-05-12, Matthew Dillon <dillon@apollo.backplane.com> wrote:
>>
>>>:What problems? I did a grep for /dev/random on 4.x and only came up
>>>:with a couple of uses in contrib/.
>>>:
>>>:> I think we should simply use /dev/urandom here,
>>>:> which is guarenteed not to block and will certainly produce a
>>>:> random enough seed for rand's tiny little seed.
>>>:
>>>:/dev/random is non-blocking in FreeBSD 5.x since it uses a different,
>>>:non-blocking algorithm.
>>>:
>>>:Kris
>>>
>>> Search the FBSD mail archives for the subject line '/dev/random'. There
>>> have been several threads. Most recently, a newfs after booting into
>>> single user would lock up until enough randomness existed for its
>>> inode seeding.
>>
>>That was driver breakage, not a misuse of /dev/random vs. /dev/urandom.
>
>
> To clarify, /dev/random and /dev/urandom are identical in FreeBSD 5.x,
> and the only purpose of keeping both around is for compatibility.
>
> If you're porting code from 5.x to a 4.x-based OS like DF, you need to
> take care because of the different semantics of the /dev/random driver
> interface. OTOH it may make sense for you to port the 5.x /dev/random
> driver itself, because it has much better properties including better
> entropy gathering and better robustness against entropy starvation.
>
> Kris
I'm not very knowledgable of the code base as a whole, yet. So, I see
what you're saying, to an extent.
I think what I've done so far would be good enough to go into DFly,
pending approval from the community. Also, beyond this, I would be
happy to port the /dev/random driver over to DFly. I can start working
on that once the rand.c/rand.3 patches are applied or denied.
Cheers!
Mike
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