3 ms·
You've got it: this is purely an issue during boot-up before enough quality entropy has been gathered. If a malicious userspace program writes predictable data
by AgentME 5y ago
You've got it: this is purely an issue during boot-up before enough quality entropy has been gathered. If a malicious userspace program writes predictable data to /dev/random immediately on boot, and the system counts it toward the entropy credit, then it's possible that other services on the system reading from /dev/random will get predictable improperly seeded randomness. It's fine to allow writes to /dev/random at any time as long as it is never given entropy credit.
- staticassertion 5y agoI see. That is a bit tricky... the entire "count the entropy" thing sounds like a pain. I guess I don't see a way around it - they link to fortuna, but I don't see how that's going to fix it. It sounds like fortuna is a better prng, so in theory if you have N outputs it's harder to get back to the seed? But the attacker is so early in the boot process... It would help I guess. I'll have to read up on Fortuna, at the least, as it sounds really neat. edit: OK Fortuna is more than I expected. I have to read up.
- zvrba 5y ago> If a malicious userspace program writes predictable data to /dev/random immediately on boot, Hmmm, how did the program get there? A case for secure boot, no? At least initialization of RNG state should be included in the trusted part.
- deleted 5y ago[deleted]