/dev/random + /dev/urandom Unification May Be Revisited In The Future, Blocker Addressed

Originally attempted with Linux 5.18 were patches so /dev/urandom and /dev/random would behave exactly the same. That was dropped though due to not enough randomness at boot for some platforms like Arm 32-bit, Motorola m68k, Microblaze, Xtensa, and others. But then the change went in to opportunistically initialize /dev/random as a best-effort approach where it at least works nicely on x86/x86_64. The good news is that original unification effort may be re-visited in the future now that the original blocker issue has been addressed.

Jason Donenfeld shared "excellent news" that the original issue affecting the various niche architectures has been addressed:

So what this means is: the rationale for reverting the /dev/random + /dev/urandom unification has now been fixed. That's some real tangible progress.

Now, I don't want to rush into trying the unification again too soon. I think if anything, the lesson from the first attempt wasn't simply, "I should fix a few of Guenter's test cases," but rather that the problem is fairly nuanced and will take a lot wider testing and research. However, the fact that the initial thing, across multiple platforms, that lead to the revert has been fixed gives me a decent amount of optimism that at /some point/ down the road, we'll be able to try this again. One step at a time.

He went on to tweet optimism for the future that the /dev/random and /dev/urandom unification may be successfully re-visited down the road.

Hopefully we'll be able to reattempt the unification of /dev/random and /dev/urandom at some point down the road. https://t.co/G93meKsluu was the first good news about the prospects for that in the future, with some very preliminary patches that chip away at the challenges. https://t.co/rgPZsiW9Tl

— Edge Security (@EdgeSecurity) April 25, 2022

See last week's patch for the fix to this latest hurdle now overcome.