x11vnc terminates with **stack smashing detected** error

[Mark Smith]

Users report this also affects 18.04 bionic.

x11vnc will terminate abnormally on zesty with a **stack smashing detected** error. Reverting to an x11vnc from an earlier Ubuntu version appears to resolve this error. The error is generated by user activity, it seems to be triggered by certain user input, such as a mouse click.

[Xlu (xlusive27)]

Same here - bug seems to affect only 0.9.13-2 but not 0.9.13-1.2 - but I had not the chance to test x11vnc v0.9.13-1.2 myself.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Xlu (xlusive27)]

Regaring 0.9.13-1.2 see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=859213

Seems to appear also in other distributions - see https://bugzilla.redhat.com/show_bug.cgi?id=1278335

[Xlu (xlusive27)]

I installed now 0.9.14.1-dev by use of the instructions outlined in the link below - that works (until now no crashes).

https://gist.github.com/mangoliou/407d6a39a60d128610c20c4143f39f0d

[Jun Kobayashi (jkbys)]

I've created x11vnc package adding the patches from https://github.com/LibVNC/x11vnc/pull/25 and works fine.
I'm attaching debdiff.

[Herman Heunis (hazza)]

Experienced a lot of the stack smashing errors using qt-wine v1.3.3 over VNC connection from my Android, I compiled and installed 0.9.14.1-dev now and no errors. Thanks

[Simon Quigley (tsimonq2)]

Hello!

In order to get this into Zesty, could you please follow the instructions here to make this an SRU bug and resubscribe ~ubuntu-sponsors when that's done? https://wiki.ubuntu.com/StableReleaseUpdates

[Spaceboy ross (spaceboyross)]

This is happening on Artful Aardvark too.

[Martin Gerlach (mgerlach)]

Also happening in 18.04 beta 1.

[Franck971 (franck-lefebure)]

https://gist.github.com/mangoliou/407d6a39a60d128610c20c4143f39f0d workaround works on a fresh Ubuntu 18.04 install

[Jonathan Kamens (jik)]

What the hell, this bug is over a year old, there are patches for it, why isn't it fixed in bionic?

[Éric Hoffman (ehoffman-videotron)]

This is fixed in 0.19.13-6
The fix is in Cosmic, but this would need to be backported to Bionic

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=881632

Regards,
Eric

[Éric Hoffman (ehoffman-videotron)]

I mean, 0.9.13-6 :)

Eric

[Éric Hoffman (ehoffman-videotron)]

I verified by installing x11vnc-data and x11vnc .deb packages from Cosmic (over the already installed Bionic version) and there's no more crash.

This is not the recommended solution though, we should have an official backport for Bionic. x11vnc is pretty much unusable with this issue though...

This issue appeared mostly when a popup appeared (when clicking on a menu for example, and the menu popup appeared).

Regards,
Eric

[David Casper (chortle-mortal)]

How does one get the x11vnc-data and x11vnc.deb packages from Cosmic to install on the Bionic?

[Robert (robert-ubuntu)]

"How does one get the x11vnc-data and x11vnc.deb packages from Cosmic to install on the Bionic?"

- download packages from a repository (eg. wget)
- with root privileges,
dpkg -i x11vnc-data_0.9.13-6_all.deb x11vnc_0.9.13-6_[arch].deb

Can confirm that have not had a crash since installation.

[David Casper (chortle-mortal)]

Yes I can confirm - no more crashes

For others like me, I went to pkgs.org and downloaded and installed:
    libjpeg62-turbo_1.5.2-2+b1_amd64.deb
    x11vnc-data_0.9.13-6_all.deb
    x11vnc_0.9.13-6_amd64.deb

Thanks for the help. Much appreciated.

[Dominique Pellé (dominique-pelle)]

I upgraded to Ubuntu-18.04.2 (up-to-date as of 2019/03/18) and keep stumbling on this crash.
It's a severe issues as x11vnc is almost unusable (crashes every few minutes).

Can the fix be backported to Ubuntu-18.04 LTS?

The bug is marked as importance "high". What else is needed to get this fix in Ubuntu-18.04 LTS?

Here is the version number on Ubuntu-18.04.2:

  $ x11vnc --version
  x11vnc: 0.9.13 lastmod: 2011-08-10

Strange, not modified since 2011?!

[Ruben Garcia (rubengarciahernandez)]

I confirm that 0.9.13-3 is affected. This seems to be the latest available version at Ubuntu 18.04.2 LTS.

The latest git is x11vnc: 0.9.16 lastmod: 2019-01-05; while Ubuntu's x11vnc: 0.9.13 lastmod: 2011-08-10 does look extremely outdated.

[sleeply4cat (sleeply4cat)]

0.9.13 crashes in Netbeans UI editor when [...] button in Properties pressed with a big chance.

[Santiago Gala (sgala)]

I'm seeing it consistently on 18.04.3 LTS. Fairly easy to reproduce by installing idle in the machine running x11vnc, starting idle and clicking in any of the menus. 9 out of 10 times it crashes x11vnc.

[Eugene Savelov (savelov)]

according to https://github.com/LibVNC/x11vnc/issues/61 there is a workaround to use option -noxrecord

[David Marzal (marzal)]

-noxrecord workaround works, also in 0.9.16 the problem seem fixed.