incorrect error message "Must run suid root for multiuser support"

[knut]

Binary package hint: screen

Ubuntu 9.04
dpkg: screen 4.0.3-11ubuntu4
screen: Screen version 4.00.03jw4 (FAU) 2-May-06

I want to join a multiuser session but get "Must run suid root for multiuser support"
but suid bit is set!

> ls -l /usr/bin/screen
-rwsr-xr-x 1 root root 2538 2009-06-02 09:54 /usr/bin/screen

[Micah Cowan (micahcowan)]

Some versions of Ubuntu had a package called "screen-profiles" that installed a wrapper around screen; it may be that, that has the suid bit set. Look for another binary in /usr/bin whose name starts with "screen" ("screen.real"? Can't remember), and suid that one.

Newer Ubuntus have that package as "byobu", and it doesn't install a wrapper any longer.

[Dustin Kirkland  (kirkland)]

screen-profiles/byobu has never set the setuid bit.

I think it would be nice if Debian/Ubuntu had a low debconf question
that would allow users to dpkg-reconfigure screen and turn that
on/off.

:-Dustin

[Micah Cowan (micahcowan)]

Dustin, I'm aware of that. However, if a user gets the message "screen needs to be run setuid", and then sets /usr/bin/screen (which is really the profiles wrapper) to setuid, and still gets that message, they'll be confused. I've seen that happen before; I suspect that's what happened here.

[Dustin Kirkland  (kirkland)]

Oh, right, I misunderstood you. Yes, Micah, I agree, that can be
confusing and I regret having ever put that dpkg-divert in place.

[Kurt Kraut (kurtkraut)]

I'm facing the same problem in Ubuntu 10.04. The suid is properly set:

ktk@ktk7:~$ ls -al /usr/bin/screen
-rwxr-sr-x 1 root utmp 376112 2009-11-10 16:54 /usr/bin/screen

I have the screen and screen-profile packages installed and I'm unable to use multiuser screen sessions:

gmazk@ktk7:~$ screen -x ktk/teste
Must run suid root for multiuser support.

[James Page (james-page)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Ubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. It would help us a lot if you could test it on a newer Ubuntu version. When you test it and it is still an issue, kindly upload the updated logs by running apport-collect 587507 and any other logs that are relevant for this particular issue.

[Launchpad Janitor (janitor)]

[Expired for screen (Ubuntu) because there has been no activity for 60 days.]