Samba (GnuTLS) bug

This has been driving me crazy for a week now. Every hour or two

  • System load on my Roon Core machine goes through the roof.
  • There are playback glitches

Coincidentally,

  • I haven’t had a good TimeMachine backup of my Mac in a week. The backups start, but never complete. Instead, they just restart.

The origin of both problems is that I upgraded my Samba Server to Ubuntu 20.04 LTS.

The directory with my music files is remote-mounted from my Samba Server. The same server provides wireless TimeMachine backups to the Macs in my home.

Samba uses GnuTLS for encryption and Ubuntu 20.04 upgraded GnuTLS to 3.6.13. Unfortunately, GnuTLS 3.6.10-14 has a memory leak when communicating with clients using AES-CCM (AES-GCM is OK). One such client is TimeMachine on a Mac.

When one of our Macs tries to do a backup, Samba starts chewing up memory on the server. First the machine starts swapping and then, eventually, the OOM Killer starts killing samba processes. As a result, the Roon Core machine starts having fits (and, of course, the backup fails).

Obviously, this is not a bug in Roon’s software (hence this is not in the Support category), but I can imagine that this combination of circumstances is not unique to me.

So, if anyone in a similar situation is wondering why Roon has suddenly gone berserk … that’s why.

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Update: There’s no released version of GnuTLS, yet, which fixes this bug. But I went ahead and compiled my own from their repository. It installed in /usr/local/lib/.

I then soft-linked /usr/lib/x86_64-linux-gnu/libgnutls.so and /usr/lib/x86_64-linux-gnu/libgnutls.so.30 to /usr/local/lib/libgnutls.so.30.28.0 (replacing the soft-links to /usr/lib/x86_64-linux-gnu/libgnutls.so.30.27.0, which I left in place).

Everything’s back to normal … :slight_smile:

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Well done! There’s to the freedom of a ‘free’ operating system.