lexmark-08z-series-driver causes update to 12.04 LTS to fail ungracefully

[Ronan Mooney]

Summary:
A linebreak in the description field of lexmark-08z-series-driver in the files:
/var/lib/dpkg/status
and
/var/lib/dpkg/available

Causes update to 12.04LTS to fail with error:
dpkg: error: parsing file '/var/lib/dpkg/available' near line 34639 package 'lexmark-08z-series-driver': blank line in value of field 'Description'
E: Sub-process /usr/bin/dpkg/returned with an error code (2)

(nb. this error also happens with var/lib/dpkg/status )

Workaround:
Had to fix setuid of /usr/lib/dbus-1.0/dbus-daemon-launch-helper due to ungraceful fail of update.
Had to manually remove the line breaks from the description field of /var/lib/dpkg/available and var/lib/dpkg/status

Proposed solutions:
* Validate /var/lib/dpkg/available and var/lib/dpkg/status prior to installation to remove linebreaks
* Fail gracefully, notify user, and fix setuid if possible.
* black list lexmark-08z-series-driver until issue is fixed

Expected:

Run update to 12.04LTS successfully

Actual:

I was updating to 12.04LTS from 11.10 (xbuntu variant)
I was using update manager, and it seemed to run through fine, it then asked to be rebooted.
After I rebooted something was wrong, mouse not moving, UI not loading up correctly etc.

I dropped into a console and ran apt-get update && apt-get upgrade. I said I had 899 packages to upgrade. To me this indicates that the package installation caused an issue during the install.

When I pressed Y to continue with apt-get upgrade, it failed with (from memory)
 "setuid invalid for dbus-daemon-launch-helper: The permission of the setuid helper is not correct"

I tried to correct this by fixing the setuid:
chmod 4755 /usr/lib/dbus-1.0/dbus-daemon-launch-helper

When I ran apt-get upgrade the set UID problem had disappeared, but now it was failing with the error at the top of the report.
I manually checked the referenced files, and there is indeed a line break after the word "description".

To recreate:
Not tested: but would recommend installing lexmark-08z-series-driver on 11.10 and then updating to 12.04LTS

NB. As of today all packages are current, I am in the middle of recovering my install, so I will update with package version numbers etc if required later.

[Launchpad Janitor (janitor)]

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