Bug#307768: exim4: check_local_user should reject system users?

[Marc Sherman]

Package: exim4
Version: 4.50-4
Severity: wishlist


It seems to me that the check_local_user router option should fail for
system users.  Some packages that create system users already put them
in /etc/aliases pointing to root, but there are a number of system users
on my machine that are not currently aliased to root.  This seems like a
maintenance hassle, and possibly a security problem.

I suspect that if you agree with me, this would be a debian specific
patch, not something upstream would accept; the concept of system users
vs. regular users seems to be a debian concept introduced in adduser.

-- Package-specific info:
Exim version 4.50 #1 built 02-Mar-2005 07:42:40
Copyright (c) University of Cambridge 2004
Berkeley DB: Sleepycat Software: Berkeley DB 4.2.52: (December  3, 2003)
Support for: iconv() IPv6 PAM Perl GnuTLS Content_Scanning Old_Demime
Lookups: lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmnz dnsdb dsearch ldap ldapdn ldapm mysql nis nis0 passwd pgsql
Authenticators: cram_md5 cyrus_sasl plaintext spa
Routers: accept dnslookup ipliteral iplookup manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore/mbx autoreply lmtp pipe smtp
Fixed never_users: 0
Configuration file is /var/lib/exim4/config.autogenerated
# /etc/exim4/update-exim4.conf.conf
#
# Edit this file and /etc/mailname by hand and execute update-exim4.conf
# yourself or use 'dpkg-reconfigure exim4-config'

dc_eximconfig_configtype='internet'
dc_other_hostnames='projectile.ca:lab403.com:groundworksdesign.ca:redthreaddesign.ca'
dc_local_interfaces=''
dc_readhost='projectile.ca'
dc_relay_domains=''
dc_minimaldns='false'
dc_relay_nets=''
dc_smarthost=''
CFILEMODE='644'
dc_use_split_config='true'
dc_hide_mailname='false'
dc_localdelivery='maildir_home'

dc_mailname_in_oh='true'
mailname:projectile.ca

-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (900, 'testing'), (300, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.6.8-2-k7
Locale: LANG=en_CA, LC_CTYPE=en_CA (charmap=ISO-8859-1)

Versions of packages exim4 depends on:
ii  exim4-base                    4.50-4     support files for all exim MTA (v4
ii  exim4-daemon-heavy            4.50-4     exim MTA (v4) daemon with extended

-- no debconf information