5 ms·

What if a filesystem error forces /var (or whichever mount point hosts the entropy seed) to remain read-only and seed is never replaced? Seems like unlike syste

• throw0101a 7y ago
  > Seems like unlike systemd the BSDs are fine with crediting entropy even if it has been used already in a previous boot. FreeBSD runs a regular cron job so that there are multiple files. If /var goes R-O, you still have a bunch of files from when it wasn't and they are not the same as on initial boot (assuming that (a) /var was mounted R-W at some point, and (b) cron managed to run as well). Also, on shutdown there is an attempt to write 4096B to both /entropy and /boot/entropy: * https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?revision=348122&view=markup https://svnweb.freebsd.org/base/head/libexec/rc/rc.d/random?... Further, all of these various seed files are not the only sources of entropy (timers, RDRAND, etc).
  • bonzini 7y ago
    > (assuming that (a) /var was mounted R-W at some point Not a good assumption if the initial r/w mount is the one that fails...
    • throw0101a 7y ago
      If the initial /var (or /) is broken, then one has bigger problems and probably has to go in manually to fix things. But for >99% of cases where the system comes up cleanly, and runs cleanly for a period of time, you'll have a bunch of seed files ready to go for the next boot. This configuration optimizes for the common case.