ruby-core

Issue #15039 has been updated by shyouhei (Shyouhei Urabe).


@naruse Are you willing to provide a fix for this? Or can I commit the proposed #if guard?

----------------------------------------
Bug #15039: Random.urandom and SecureRandom arc4random use
https://bugs.ruby-lang.org/issues/15039#change-73856

* Author: Freaky (Thomas Hurst)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
Random.urandom defaults to arc4random() on a lot of platforms, including FreeBSD.

On all currently released versions of FreeBSD, arc4random() is, as the name suggests, a dubious ARC4-based userspace PRNG dating from circa 1997.  Given the entire point of #9569 was that using the userspace CSPRNG in OpenSSL over /dev/urandom or equivalent is a bad idea, this seems to mean it's regressed to an *even worse* state on these platforms.  Even in cases where it's using something more modern (FreeBSD 12, OpenBSD), it's still a userspace CSPRNG.

If that's fine, we might as well *pick a known-good one* and use that everywhere.  Like, say, OpenSSL's.

Since the conclusion of #9569 seems to have been otherwise, I'd suggest dropping arc4random() as a potential source for Random.urandom due to it not matching the desired semantics.

Rust's OsRng seems a good template for alternative _syscall implementations: https://docs.rs/rand/0.5.5/rand/rngs/struct.OsRng.html#platform-sources



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:[email protected]?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>