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Date:      Mon, 3 Feb 2003 00:56:32 +0000
From:      Edward Brocklesby <ejb@lythe.org.uk>
To:        Don <don@calis.blacksun.org>, current@FreeBSD.ORG
Subject:   Re: rand() is broken
Message-ID:  <200302030056.32009.ejb@lythe.org.uk>
In-Reply-To: <20030202193215.E2519@calis.blacksun.org>
References:  <200302021848.NAA19508@agamemnon.cnchost.com> <200302030026.33781.ejb@lythe.org.uk> <20030202193215.E2519@calis.blacksun.org>

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On Monday 03 February 2003 12:41 am, Don wrote:
> I think Terry mentioned binary packages simply because it is harder to fix
> them than something available as source but I could be mistaken.

Possibly -- if we're looking at this from the point of view of the user of 
said binary package, rather than the developer (as I'd assumed), then I see 
what you mean (you can do ld hacks and so on, but ..)

> > I'm not sure Yet Another RNG API (of course arc4random() already exists)
> > gains anything unless rand()/random() absolutely cannot be changed; and
> > as I say I'm not convinced this is the case.
>
> I am by no means convinced either. I do, however, think this is something
> that should not be changed without a lot of consideration and testing.

IMHO, it "shouldn't" break things (ie, things shouldn't be relying on it); 
but, well, I can accept there might be something that does.  I do find it 
hard to believe though; this 'simulation' problem is the first I've heard of 
it, and it doesn't look like an insurmountable one.

> Your point about arc4random() is a good one. Why depend on rand() for
> cryptographic randomness when we already have arc4random()?

Because arc4random() is not portable.  I would rather rely on the OS having a 
useful rand() RNG rather than #ifdef'ing on this that and the other to choose 
the correct one.

> > Doesn't even the 0 / RAND_MAX fix change
> > the algorithm?  Software which relies on that behaviour will break ..
>
> [...] I don't recall advocating that change either.

Well, no -- but are you against it?  Where is the line drawn?

Regards,
Edward.

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