> They are just following the man page.

I think Ruby devs' position is more than this. By keeping the faulty man page, Linux maintainers are implicitly communicating that they intended `/dev/urandom` to be a limited and less recommended way of doing things. The intention is important: even though `/dev/urandom` is actually better in the current kernel it may not in the future. It is not the only answer, as other languages did another choice, but it is perfectly reasonable to be conservative like this.

We badly need to change that intention, really.

Exactly what, do you imagine, Linux could do to make urandom less secure? I'm sorry, but the word for that concern is "nonsensical". Linus Torvalds has world-shattering conniption fits when developers make changes that hurt performance. Can you imagine breaking every one of the many security applications --- for instance, every Go program ever written --- that depend on urandom?

No, that is not a legitimate concern.

> What else is the authoritarian source?

Basically everything else. If you see how manpages are written, or just how often they are out of date, you quickly arrive at the conclusion that they are not authoritative source at all. Add in the political plays done in this area. Being stubborn over a wrong manpage is very frightening, especially in a security context. This thread shakes my believe in ruby as a language.

The authoritative source in Linux is the code and always has been.

Code is useless if no one knows how to use it properly and it's not communicated clearly. Users certainly can't be expected to read every line of code. That's like shipping a car with no user manuals and saying "take the engine apart and see how it works." Arrogance.

Clearly document system behavior or code is essentially useless.

Users of languages can't be expected to. Therefore the language designers and maintainers themselves, especially if they're working on the stdlib, should do so, IMO. It's not only education for a proficient programmer, it helps to understand the underlying system you're building on and it's security assumptions.

The random char device code isn't that hard to understand, and if you're not a strong C programmer (the Ruby-core people are good C programmers, I suppose) - there's a paper explaining how it works: https://eprint.iacr.org/2012/251.pdf

Aaron

Then I have a little quiz for you:

According to this documentation:

http://ruby-doc.org/core-2.1.2/Float.html#method-i-round

How do you explain?

2.1.2 :011 > 15.round(-1) => 20

I think that's hardly the case. If Linux users were reading the source code, we wouldn't have such an embarrassing track record when it comes to security. Major security issues like Heartbleed existed in code for years.

Agreed. The problem is the man page. Suggesting that one should read the source code instead of the man page is ridiculous. Might as well write your own kernel while you're at it if that's the case.