passwd command problems if libpam-script is installed in xenial

[Victor Mora]

We are using ubuntu xenial (16.04).

The command passwd has a problem when you install the package libpam-script.

If you install package libpam-script, then passwd command asks for old user password to root user:

root@myhost:~# passwd user
Current password:

The passwd command should not ask for current password to root.

Details of the system:

$ lsb_release -rd
Description: Ubuntu 16.04.3 LTS
Release: 16.04

$ cat /etc/issue
Ubuntu 16.04.3 LTS \n \l

$ uname -a
Linux myhost 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

root@myhost:~# ls -la `which passwd`
-rwsr-xr-x 1 root root 54256 May 17 01:37 /usr/bin/passwd

# dpkg -l passwd libpam-script
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===========================-==================-==================-============================================================
ii libpam-script 1.1.7-1 amd64 PAM module which allows executing a script
ii passwd 1:4.2-3.1ubuntu5.3 amd64 change and administer password and group data

# apt-cache policy libpam-script
libpam-script:
  Installed: 1.1.7-1
  Candidate: 1.1.7-1

I've tested this behaviour in a clean installation.

[Launchpad Janitor (janitor)]

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