package postfix 3.1.0-3 failed to install/upgrade: Unterprozess installiertes post-installation-Skript gab den Fehlerwert 75 zurück

[Jackow]

During apt dist-upgrade postfix was automatically installed, which wasn't previously.
As I thought, this would only be for root messages purpose, I decided to install with local-only transport. After that the system informed me, that postfix has not been installed correctly.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: postfix 3.1.0-3
ProcVersionSignature: Ubuntu 4.4.0-71.92-lowlatency 4.4.49
Uname: Linux 4.4.0-71-lowlatency i686
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: i386
Date: Sat Apr 1 17:44:45 2017
ErrorMessage: Unterprozess installiertes post-installation-Skript gab den Fehlerwert 75 zurück
EtcMailname: monster.mello
Hostname: monster.mello
PostconfMydomain: mello
PostconfMyhostname: monster.mello
PostconfMyorigin: /etc/mailname
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.4~rc2~ubuntu16.04.1~c42.ppa1
ResolvConf:
 # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
 # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
 nameserver 192.168.0.1
 search mello
SourcePackage: postfix
Title: package postfix 3.1.0-3 failed to install/upgrade: Unterprozess installiertes post-installation-Skript gab den Fehlerwert 75 zurück
UpgradeStatus: No upgrade log present (probably fresh install)

[Christian Ehrhardt  (paelzer)]

Hi Jackow,
Thank you for taking the time to report this bug and helping to make Ubuntu better.

first as it might be interesting to you in general you might run
$ aptitude why postfix
This should help to understand by which dependency (chain) this is now installed.
If the discussion on the bug goes on reporting here would also be nice.

From the Log:
newaliases: fatal: file /etc/postfix/main.cf: parameter setgid_group: group postdrop has same group ID as mlocate

I think that is the root cause.
There was a similar issue and some analysis a long long time ago in bug 378955
But no other report I heard of.

Is there something special to your mlocate setup?

To be sure please report back with
$ id mlocate
$ id postdrop

But much more IIRC this belongs to the setuid on newaliases.
newaliases is a symlink and depending on your current mailer points to something else, for example:
$ ll /usr/sbin/newaliases
lrwxrwxrwx 1 root root 5 Apr 13 2016 /usr/sbin/newaliases -> ssmtp*

In your case likely from postfix.
Please check the target of that link and report it here:
$ ls -laF $(readlink -f /usr/sbin/newaliases)

And since these are groups not users you might want to check with
$ getent group <groupname>
Use as groupname
1. mlocate
2. postdrop
3. whatever is the group of the link you checked above

Since it seems likely to me that this is a local configuration problem, rather than a bug in Ubuntu, I'm marking this bug as Incomplete.

If you expect this to be a bug in Ubuntu please provide the inquired information and set it back to status new.

[Launchpad Janitor (janitor)]

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