[not openntpd bug] openntpd hangs Debian Stretch kernel 4.9.0-6-686-pae

[rlucassen2]

Just updated Debian Stretch kernel to version 4.9.0-6-686-pae (4.9.88) and I noticed that during the first 5 minutes uptime all UDP123 packets are blocked somehow (I can't see them going out the interface with tcpdump on eth0). The program rdate suffers from the same issue. After 5 minutes traffic is possible and everything runs as expected. Downgrading to the previous version of the kernel resolves the problem. I'm running a sys-V system (no systemd)

strace rdate shows:
getrandom(

strace ntpd shows:
restart_syscall(<... resuming interrupted poll ...>

2018-05-02 13:37:38.466904500 ntp engine ready
2018-05-02 13:37:53.403464500 no reply received in time, skipping initial time setting
(ntps starts with -s)

Note: this is NOT an openntpd issue, but can someone maybe shine a light on this issue?

R.

[rlucassen2]

Hmmm, dmesg tells this:

[ 303.157763] random: crng init done

[rlucassen2]

Apparently servers running on proxmox seem to suffer from this issue. Servers running on Hyper-V have no problems. Anyway, there is a big difference between the up2date kernel version and the previous one.

R.

[rlucassen2]

Here's an explanation:

https://security-tracker.debian.org/tracker/CVE-2018-1108
https://bugs.chromium.org/p/project-zero/issues/detail?id=1559

R.