postfix/postfix.sh



#!/bin/sh
#
# /etc/local-COMMON/postfix/postfix.sh
# Copyright 2002-2007 Jonas Smedegaard <dr@jones.dk>
#
# $Id: postfix.sh,v 1.63 2007-12-11 14:29:54 jonas Exp $
#
# Auto-tweak plain installed postfix Debian package
#
# TODO:
#  * Implement stuff from here: http://www.wsrcc.com/spam/
#  * Implement stuff from here: http://www.muine.org/~hoang/postfix.html
#  * Implement stuff from here: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt
#  * Figure out a way to use chroot jail for TLS stuff.

set -e

# Let's standardize sort
export LC_ALL=C

exit1() {
    echo >&2 "Error: $1"
    echo >&2 "Exiting..."
    exit 1
}

realmsdir='/etc/local-REDPILL'
configdirs='/etc/local/postfix /etc/local-ORG/postfix /etc/local-REDPILL/postfix /etc/local-COMMON/postfix'
confdir='/etc/postfix'
postconf=/usr/sbin/postconf
sp='[[:space:]]'
if ! $postconf -d mail_version | egrep -q '= 2\.[2-9]'; then
    exit1 "ERROR: Bad postfix version - this script is known to work only for postfix 2.2 and later"
fi
if ! [ -d "$realmsdir" ]; then
    echo >&2 "WARNING: Realms directory \"$realmsdir\" does not exist."
fi
#postgrey=
#if [ -x /usr/sbin/postgrey ]; then
#   # FIXME: Use this somehow, and only warn below
#   postgrey=1
#else
#   exit1 "ERROR: Greylisting support (Debian package postgrey) missing."
#fi
# FIXME: We really want to check for at least 2.1.1 but that's tricky...
sasl2=
if saslauthd -v 2>&1 | grep -q '^saslauthd 2.1'; then
    sasl2=1
else
    echo >&2 "WARNING: Encryption requires sasl tools 2.1.1 (Debian package sasl2-bin)."
fi
saslsubdir="sasl"

catfilefromownrealm() {
    file="$1"
    [ -d "$realmsdir" ] || exit 0

    thisrealm="$(cat /etc/local-ORG/realm || dnsdomainname | tr '[a-z]' '[A-Z]')"

    cat "$realmsdir/$thisrealm/$file"
}

catallfilesfromotherrealms() {
    file="$1"
    [ -d "$realmsdir" ] || exit 0
    [ -f "$realmsdir/realms" ] || exit 0

    realms="$(cat "$realmsdir/realms" | sed 's/#.*//')"
    thisrealm="$(cat /etc/local-ORG/realm || dnsdomainname | tr '[a-z]' '[A-Z]')"

    for realm in $realms; do
        if [ "$thisrealm" != "$realm" ]; then
            cat "$realmsdir/$realm/$file"
        fi
    done
}

catfirstfile() {
    file="$1"
    configdir=''
    for dir in $configdirs; do
        if [ -d "$dir" ] && [ -f "$dir/$file" ]; then
            configdir="$dir"
            break
        fi
    done
    if [ -z "$configdir" ]; then
        exit1 "ERROR: file \"$file\" not found."
    fi
    cat "$configdir/$file"
}

getlinesfromfile() {
    param="$1"
    shift
    replacements=
    for subparam in $@; do
        case "$subparam" in
            *=*=*)
            oldparam="`echo $subparam | awk -F= '{print $1}'`"
            newparam="`echo $subparam | awk -F= '{print $2}'`"
            newparamfile="`echo $subparam | awk -F= '{print $3}'`"
            shift
            ;;
            *)
            oldparam=$subparam
            newparam=$subparam
            newparamfile=$subparam
            shift
            ;;
        esac
        newparamvalues="`getlinesfromfile $newparamfile | sed -e 's/.*=[ ]*//' -e 's/,/ /g'`"
        newstring=
        for newparamvalue in $newparamvalues; do
            newstring="${newstring}$newparam $newparamvalue,"
        done
        replacements="$replacements;s/$oldparam/$newstring/"
    done
    echo -n "$param = "
    catfirstfile "$param" | sed 's/#.*//' | tr '\n' ',' | sed -e 's/^[,     ]*//;s/[,   ]\+/,/g' -e 's/\^/ /g' -e "s/,\$//$replacements"
}

postmapfiles=

tempdir="$(mktemp -td postfix.XXXXXX)"
cp -a -t "$tempdir" "$confdir"/*

# Inspired by D. J. Bernstein: http://cr.yp.to/smtp/greeting.html
$postconf -c "$tempdir" -e 'smtpd_banner = $myhostname NO UCE ESMTP $mail_name (Debian/GNU)'

# Some badly configured setup use hostname instead of FQDN
# Disable completely: Effective, but hurts executive type guys using windows servers... :-(
#if $postconf -c "$tempdir" myhostname | grep -q '\.'; then
#   $postconf -c "$tempdir" -e 'smtpd_helo_required = yes'
#fi
$postconf -c "$tempdir" -e 'smtpd_helo_required = no'
$postconf -c "$tempdir" -e "`getlinesfromfile permit_mx_backup_networks`"
$postconf -c "$tempdir" -e "maps_rbl_domains ="
$postconf -c "$tempdir" -e "`getlinesfromfile smtpd_client_restrictions reject_rhsbl_client`"
$postconf -c "$tempdir" -e "`getlinesfromfile smtpd_helo_restrictions`"
$postconf -c "$tempdir" -e "`getlinesfromfile smtpd_sender_restrictions reject_rhsbl_sender`"
$postconf -c "$tempdir" -e "`getlinesfromfile smtpd_recipient_restrictions reject_maps_rbl=reject_rbl_client=maps_rbl_domains`"
$postconf -c "$tempdir" -e "`getlinesfromfile smtpd_data_restrictions`"

# Verify senders of common suspicious and known verifiable domains
# (exclude verification of postmaster@ to not verify verification probes)
# (add own domains before peers for (rare) cases of duplicates)
# FIXME: somehow do this step only if enabled in smtpd_sender_restrictions
# TODO: Properly implement exception exclusion like yahoo (which does not want to be checked any longer!)
cat /etc/local-COMMON/postfix/maildomains | grep -v yahoo | sort | sed 's/$/    reject_unverified_sender/' > "$tempdir/sender_access"
( catfilefromownrealm maildomains | sort; catallfilesfromotherrealms maildomains | sort ) \
    | sed 's/\(.*\)$/postmaster@\1  permit\n\1  reject_unverified_sender/' >> "$tempdir/sender_access"
postmapfiles="$postmapfiles sender_access"
$postconf -c "$tempdir" -e "unverified_sender_reject_code = 550"

# Trust recipient verification too
$postconf -c "$tempdir" -e "unverified_recipient_reject_code = 550"

# TLS breaks postfix if no SASL modules available (and doesn't make sense either)
# (change the test if using some other modules and avoid the plain ones)
if [ -n "$sasl2" ] && [ -f /etc/ssl/certs/postfix.pem ]; then
    mkdir -p "$tempdir/$saslsubdir"
    echo 'mech_list: plain login' > "$tempdir/$saslsubdir/smtpd.conf"
    echo 'minimum_layer: 0' >> "$tempdir/$saslsubdir/smtpd.conf"
    echo 'sasl_pwcheck_method: saslauthd' >> "$tempdir/$saslsubdir/smtpd.conf"
    echo 'auto_transition: false' >> "$tempdir/$saslsubdir/smtpd.conf"
    groups postfix | grep -q sasl || echo "adduser postfix sasl" >> "$tempdir/COMMANDS"
    # Release TLS-related daemons from chroot jail (bringing SASL into the jail is just too messy)
    sed --in-place \
        -e "s/^\(smtp$sp\+inet\($sp\+[n-]\)\{2\}$sp\+\)[n-]\(\($sp\+-\)\{2\}$sp\+smtpd\).*/\1n\3 -o smtpd_sasl_auth_enable=yes/" \
        -e "s/^#\?\(\(smtps\|587\)$sp\+inet\($sp\+[n-]\)\{2\}$sp\+\)[n-]/\1n/" \
        -e "s/^#\(tlsmgr$sp\)/\1/" \
        "$tempdir/master.cf"
    cat $tempdir/master.cf | egrep -q "^tlsmgr$sp" || \
        echo 'tlsmgr      unix  -   -   -   300 1   tlsmgr' >> $tempdir/master.cf
    $postconf -c "$tempdir" -e 'smtpd_tls_cert_file = /etc/ssl/certs/postfix.pem'
    if [ -f /etc/ssl/private/postfix.pem ]; then
        $postconf -c "$tempdir" -e 'smtpd_tls_key_file = /etc/ssl/private/postfix.pem'
    fi
    $postconf -c "$tempdir" -e 'smtpd_tls_loglevel = 1'
    $postconf -c "$tempdir" -e 'smtpd_use_tls = yes'
    $postconf -c "$tempdir" -e 'smtp_tls_CApath = /etc/ssl/certs'
    $postconf -c "$tempdir" -e 'smtpd_tls_CApath = /etc/ssl/certs'
    $postconf -c "$tempdir" -e 'lmtp_tls_CApath = /etc/ssl/certs'
    $postconf -c "$tempdir" -e 'smtpd_tls_key_file = /etc/ssl/private/postfix.pem'
    $postconf -c "$tempdir" -e 'smtpd_tls_session_cache_database = btree:/var/spool/postfix/smtpd_scache'
    $postconf -c "$tempdir" -e 'smtpd_tls_session_cache_timeout = 3600s'
    $postconf -c "$tempdir" -e 'tls_random_exchange_name = /var/spool/postfix/prng_exch'
    $postconf -c "$tempdir" -e 'smtpd_tls_auth_only = yes'
    $postconf -c "$tempdir" -e 'smtpd_sasl_auth_enable = no' # SASL is enabled explicitly with TLS transport
    $postconf -c "$tempdir" -e 'smtpd_sasl_security_options = noanonymous'
    $postconf -c "$tempdir" -e 'smtpd_sasl_local_domain = '
    $postconf -c "$tempdir" -e 'smtpd_tls_received_header = yes'
    $postconf -c "$tempdir" -e 'broken_sasl_auth_clients = yes'
    $postconf -c "$tempdir" -e 'tls_random_source = dev:/dev/urandom'
    $postconf -c "$tempdir" -e 'tls_daemon_random_source = dev:/dev/urandom'
    # Check if using a proper key exists (not just a self-signed one)
    # (it is assumed that a CA certificate is made public if used!)
    if [ -f /etc/ssl/certs/cacert.pem ]; then
        $postconf -c "$tempdir" -e 'smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem'
        # Client side TLS only makes sense if a publicly available certificate is available
        # (and DON'T publish a self-signed certificate!)
        $postconf -c "$tempdir" -e 'smtp_tls_CAfile = /etc/ssl/certs/cacert.pem'
        $postconf -c "$tempdir" -e 'smtp_tls_cert_file = /etc/ssl/certs/postfix.pem'
        if [ -f /etc/ssl/private/postfix.pem ]; then
            $postconf -c "$tempdir" -e 'smtp_tls_key_file = /etc/ssl/private/postfix.pem'
        fi
        $postconf -c "$tempdir" -e 'smtp_tls_loglevel = 1'
        $postconf -c "$tempdir" -e 'smtp_use_tls = yes'
        $postconf -c "$tempdir" -e 'smtp_tls_CApath = /etc/ssl/certs'
        $postconf -c "$tempdir" -e 'smtp_tls_note_starttls_offer = no' # Enable to collect info for smtp_tls_per_site option
        $postconf -c "$tempdir" -e 'smtp_tls_session_cache_database = btree:/var/spool/postfix/smtp_scache'
        # Accepting client certificates breaks SMTP AUTH on OutLook Express on Mac (Classic)
        $postconf -c "$tempdir" -e 'smtpd_tls_ask_ccert = no'
        # Force using TLS for peers
        catallfilesfromotherrealms mailhost | sort | sed 's/^/[/;s/$/]:submission   secure/' > "$tempdir/tls_policy"
        postmapfiles="$postmapfiles tls_policy"
        $postconf -c "$tempdir" -e "smtp_tls_policy_maps = hash:$confdir/tls_policy"
    else
        echo >&2 "WARNING: CA certificate not found - consider using proper signed certificates!"
    fi
else
    echo >&2 'WARNING: TLS not activated - check the script for requirements...'
fi

if [ -x /usr/sbin/amavisd ] || [ -x /usr/sbin/amavisd-new ]; then
    $postconf -c "$tempdir" -e 'max_use = 10' # Avoid too much reuse
    cat $tempdir/master.cf | egrep -q "^smtp-amavis$sp" || \
        cat >> $tempdir/master.cf << EOF
smtp-amavis unix -  -   n   -   5   smtp
    -o smtp_data_done_timeout=1200s
    -o smtp_never_send_ehlo=yes
    -o smtp_send_xforward_command=yes
    -o disable_dns_lookups=yes
    -o max_use=20
EOF
    cat $tempdir/master.cf | egrep -q "^127.0.0.1:10025$sp" || \
        cat >> $tempdir/master.cf << EOF
127.0.0.1:10025 inet n  -   n   -   -   smtpd
    -o content_filter=
    -o local_recipient_maps=
    -o relay_recipient_maps=
    -o smtpd_restriction_classes=
    -o smtpd_delay_reject=no
    -o smtpd_client_restrictions=permit_mynetworks,reject
    -o smtpd_helo_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o mynetworks_style=host
    -o mynetworks=127.0.0.0/8
    -o strict_rfc821_envelopes=yes
    -o smtpd_error_sleep_time=0
    -o smtpd_soft_error_limit=1001
EOF
    $postconf -c "$tempdir" -e 'content_filter = smtp-amavis:[127.0.0.1]:10024'
fi

diff -ruN "$confdir" "$tempdir" || if [ $? -gt 1 ]; then exit $?; fi

if [ "$force" = "1" ]; then
    do_update="y"
else
    echo -n "Above is the intended changes. OK to update (y/N)? "
    read do_update
fi
case $do_update in
    y|Y)
    if [ -f "$tempdir/COMMANDS" ]; then
        sh -c "$tempdir/COMMANDS"
    fi
    rm -f "$tempdir/COMMANDS"

    cp -a -f -t "$confdir" "$tempdir"/*
    rm -rf "$tempdir"

    for file in $postmapfiles; do
        postmap "$confdir/$file"
    done

    # FIXME: restart if master.conf has been edited
    invoke-rc.d postfix reload

    echo >&2 "Changes applied!"
    ;;
    *)
    exit1 "Aborted!"
    ;;
esac

# Based on this: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt
# Support for trusted MX backup networks added
# PCRE stuff avoided, as PCRE is only optional on newest Debian packages
# RBLs replaced with those recommended by http://www.antispews.org/
# AMaViS tweaks as documented in amavisd-new package
# AUTH-SMTP based on these:
#   http://lists.q-linux.com/pipermail/plug/2003-July/029503.html
#   http://www.porcupine.org/postfix-mirror/newdoc/SASL_README.html

# Here's a convenient overview of different blackholes:
#   http://rbls.org/

# smtpd_tls_CAfile