Latest Samba updates from NTGR broken

First off: If you’re not updating your ReadyNAS from the command line you’re most likely not affected.
Also, if you never logged into your ReadyNAS using SSH, you’re most likely not affected.

However, if you’re updating your ReadyNAS from the SSH command line using something along the lines of apt update && apt full-upgrade chances are that you received the latest, broken updates to the samba packages, identified by the extension netgear4 to their version number.

This update by NTGR should provide a fix for CVE-2021-44142. However, in the process this fix seems to have broken the connection between the samba daemons and the central system daemon that monitors whether a service is running or not. As a result your SMB services won’t start anymore. Or to be more precise: they will start but since they can’t report back their status to systemd they’ll be killed again right away by systemd.

The quick fix

To fix this and revert to the old versions of samba without the broken fix you need to

  • log into your ReadyNAS using SSH as the user “root”
  • run the following command
    apt install samba=2:4.8.0-12.netgear3 \
    samba-common-bin=2:4.8.0-12.netgear3 \
    samba-common=2:4.8.0-12.netgear3 \
    samba-libs=2:4.8.0-12.netgear3 \
    libwbclient0=2:4.8.0-12.netgear3 \
    samba-vfs-modules=2:4.8.0-12.netgear3 \
    winbind=2:4.8.0-12.netgear3 \
    libnss-winbind=2:4.8.0-12.netgear3 \
    smbclient=2:4.8.0-12.netgear3

I have no idea why NTGR published the broken samba packages seemingly without proper testing. Most likely their dev environment doesn’t exhibit the problem between samba and systemd.