3 ms·

Have you read systemd's code comments regarding rdrand? It's quite a reasonable explanation

• ezoe 7y ago
  I have just read it. Well I have to say it's quite a reasonable. https://github.com/systemd/systemd/blob/f90bcf8679e8708788290519dc09371e60c6fc82/src/basic/random-util.c#L34 https://github.com/systemd/systemd/blob/f90bcf8679e870878829...
  • jammygit 7y ago
    "In such an environment using getrandom() synchronously means we'd block the entire system boot-up until the pool is initialized, i.e. very long." How long is very long? 100ms, or 10s?
    • megous 7y ago
      "It is very common that initialization of the random pool takes a longer time (up to many minutes..." And it's my experience, too. It's one reason to install something like haveged. I had boot delays in the range of minutes, without it.
    • terom 7y ago
      Debian buster VM on an old CPU without RDRAND takes about 5 minutes for the kernel crng init to complete and for sshd to start accepting connections. Stracing the sshd process shows that it's indeed blocked on `getrandom()`. In some ways, it's very much WONTFIX because something like sshd might actually need the entropy. I'm glad that systemd has proper workarounds implemented so that the machine actually boots out of the box, though.
  • viraptor 7y ago
    > So, you are a "security researcher", and you wonder why we bother Oh, the art of insulting the audience in the first line of a message intended for them. And it ends up being the person you'd expect to write it.
  • chronogram 7y ago
    First you call people idiots and then you say it’s reasonable without apology. Classic.
    • ezoe 7y ago
      I still believe we shall never relies on rdrand because we cannot trust the hardware RNG implementation. For me, anybody who use rdrand a idiot unless it's a video game. I said "reasonable" for their argument. I do not agree with them.