Bug #1753470 “Postconf segfaults every 5 minutes” : Bugs : postfix package : Ubuntu

[Impact] Postfix segfaults when it can't read a map file. Any users without access to the file will get a core dump when running postfix. This fix checks that the file was successfully opened before doing any other checks. [Test Case] $ lxc launch ubuntu:bionic tester $ lxc exec tester bash # apt dist-upgrade # apt install -y postfix # touch /etc/postfix/valiases.cf # chmod 0600 /etc/postfix/valiases.cf # echo "virtual_alias_maps = pgsql:/etc/postfix/valiases.cf" >> /etc/postfix/main.cf ...