← Back to context

Comment by hedora

7 years ago

My reading is that systemd uses the cryptographically secure rng to generate a unique id for a filename, and doesn't handle collisions properly.

sigh

5 comments

hedora

Reply
floatboth  7 years ago

Well, not handling collisions helps a lot with exposing bad CSPRNGs. If they (and e.g. OpenSSH as mentioned in the original 2014 bug report) did handle collisions, it could've remained unnoticed.

rwmj  7 years ago

There shouldn't be collisions. I mean that really: if you see a collision it's so much more likely that your computer / program / source of randomness is faulty [as in this case] than that the two random numbers collided that it's not worth considering the collision case.

  • lokedhs  7 years ago

    But there can be collisions, at least in theory. And as we can see, in practice too.

    Not checking for collisions because you trust that an RNG returns unique values is a fallacy and should be avoided. Especially since it's so easy to deal with the problem.