I have small script that invokes another shell script as root thus:

#!/bin/bash
echo "mypass" | sudo -p '' -S /usr/StorMan/StorMan.sh

when running under Ubuntu 16.04 LTS (sudo 1.8.16 I think)this didn't display a password prompt which I understand to be correct behaviour. Since upgrading to Ubuntu 18.04.1 LTS the output looks like:

amonra@Charon:~$ ./storman
[sudo] password for amonra:

which as far as I can determine is not correct.

I originally reported this here:

https://bugs.launchpad.net/ubuntu/+source/sudo/+bug/1799857

but the Ubuntu team have found that the sudo binary in question actually works correctly on earlier releases on Ubuntu so this may not be related to changes between 1.8.16 and 1.8.21 but something more complex - either way that have decided not to investigate further.

I tried to work out from the source how this problem might happen, but failed :(.

Thanks
Dave

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: sudo 1.8.21p2-3ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-38.41-generic 4.15.18
Uname: Linux 4.15.0-38-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: LXDE
Date: Thu Oct 25 03:07:27 2018
InstallationDate: Installed on 2016-03-28 (940 days ago)
InstallationMedia: Ubuntu-Server 14.04.4 LTS "Trusty Tahr" - Release amd64 (20160217.1)
SourcePackage: sudo
UpgradeStatus: Upgraded to bionic on 2018-10-22 (2 days ago)
VisudoCheck:
 /etc/sudoers: parsed OK
 /etc/sudoers.d/README: parsed OK