tty login sessions do not correctly get updated in /var/run/utmp

[Simone F.]

Binary package hint: login util-linux (getty) ? coreutils (who) ?
The list of programs which rely on utmp may be very long, the one of those which modify it is shorter but as I am not into base sysadmin I do not know exactly.

It is best to list the steps to reproduce:

1) from X go to tty2 CTRL+ALT+F2 and login (me as user tst)

2) logout from tty2 (with `exit`)

3) go to tty1 and login (again me as user tst)

4) then I check the list of (active) sessions (with some common admin commands)
From this I can clearly see that /var/run/utmp does not get correctly updated, while /var/log/wtmp yes, so programs which rely on utmp file only may get misleaded..

Follows ouput from some test command (after the above steps):
     ==> w
 04:02:44 up 11:54, 3 users, load average: 0,88, 1,02, 1,00
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
tst tty1 - 03:52 9:35 0.62s 0.37s -bash
tst :0 - 16:09 ?xdm? 28:10 0.13s /bin/sh /opt/kde3/bin/startkde
        ==> who
tst tty1 2010-04-30 03:52
tst :0 2010-04-29 16:09
        ==> last -f /var/run/utmp
tst :0 Thu Apr 29 16:09 still logged in
tst tty1 Fri Apr 30 03:52 still logged in
tst tty2 Fri Apr 30 03:51 gone - no logout
reboot system boot 2.6.32-21-generi Thu Apr 29 16:08 - 04:02 (11:53)

utmp begins Thu Apr 29 16:08:55 2010
        ==> last -f /var/log/wtmp |head -5
tst tty1 Fri Apr 30 03:52 still logged in
tst tty1 Fri Apr 30 03:52 - 03:52 (00:00)
tst tty2 Fri Apr 30 03:51 - 03:52 (00:00)
tst tty2 Fri Apr 30 03:51 - 03:51 (00:00)
tst :0 Thu Apr 29 16:09 still logged in

        ==> pgrep tty
root 928 899 8 Apr29 tty8 00:59:07 /usr/bin/X -br -nolisten tcp :0 vt8 -auth /var/run/xauth/A:0-odCnsb
root 1053 1 0 Apr29 tty4 00:00:00 /sbin/getty -8 38400 tty4
root 1057 1 0 Apr29 tty5 00:00:00 /sbin/getty -8 38400 tty5
root 1081 1 0 Apr29 tty3 00:00:00 /sbin/getty -8 38400 tty3
root 1083 1 0 Apr29 tty6 00:00:00 /sbin/getty -8 38400 tty6
root 2459 1 0 Apr29 tty1 00:00:00 /bin/login --
root 19513 1 0 03:52 tty2 00:00:00 /sbin/getty -8 38400 tty2
tst 19630 2459 0 03:52 tty1 00:00:00 -bash

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: login 1:4.1.4.2-1ubuntu2
ProcVersionSignature: Ubuntu 2.6.32-21.32-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-21-generic i686
Architecture: i386
Date: Fri Apr 30 03:55:57 2010
InstallationMedia: Kubuntu 9.10 "Karmic Koala" - Beta i386 (20090929.2)
ProcEnviron:
 PATH=(custom, user)
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: shadow

Notes:
1) I do not have byoybu enabled on the user account profile
2) I did not make any change to the init for ttys (ie getty -8 38400 ttyX)
3) This seems to occur only on logout event, that utmp does not get correctly updated, on login it may reflect reality instead.

[Simone F. (fittabile)]

I am not completely aware of a security implication of this bug, but possibly the non correct update of utmp by (?) program would lead to some race condition and may be security bug in other applications.
I just tagged security, to draw dev attentions, becuase it could be server related, too.

[DeletedUser_799269263ahd73hd (goodbyemoonman-deactivatedaccount)]

This bug affects my project, but its fix is far beyond the scope of my project. Relevant but not fixable within the ubuntu-desktop-minimal project.

[DeletedUser_799269263ahd73hd (goodbyemoonman-deactivatedaccount)]

This bug affects my project, but its fix is far beyond the scope of my project. Relevant but not fixable within the ubuntu-desktop-minimal project. (didn't realize I could post a comment straight to this section, my mistake for posting it below.)

[Marc Deslauriers (mdeslaur)]

@Scott: could this be upstart-related? Feel free to ridicule me if it isn't. :)