/etc/init/passwd.conf is in passwd 1:4.1.5.1-1ubuntu9.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | # passwd - clear locks on passwd and related files
#
# Copyright 2012 Canonical Ltd.
# Author: Dmitrijs Ledkovs
#
# This helper clears locks on passwd to avoid million duplicate bug reports
# like this one: https://launchpad.net/bugs/523896
# Ideally we'd know what lock-up, and doesn't clear the lock, and fix that.
# But it appears to be safe enough to clear them unconditionally on boot.
#
description "Clear passwd locks"
start on filesystem
task
exec rm -f /etc/gshadow.lock /etc/shadow.lock /etc/passwd.lock /etc/group.lock
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