359 lines
15 KiB
Bash
Executable File
359 lines
15 KiB
Bash
Executable File
source /etc/mailinabox.conf
|
|
source setup/functions.sh # load our functions
|
|
|
|
# Basic System Configuration
|
|
# -------------------------
|
|
|
|
# ### Set hostname of the box
|
|
|
|
# If the hostname is not correctly resolvable sudo can't be used. This will result in
|
|
# errors during the install
|
|
#
|
|
# First set the hostname in the configuration file, then activate the setting
|
|
|
|
echo $PRIMARY_HOSTNAME > /etc/hostname
|
|
hostname $PRIMARY_HOSTNAME
|
|
|
|
# ### Fix permissions
|
|
|
|
# The default Ubuntu Bionic image on Scaleway throws warnings during setup about incorrect
|
|
# permissions (group writeable) set on the following directories.
|
|
|
|
chmod g-w /etc /etc/default /usr
|
|
|
|
# ### Add swap space to the system
|
|
|
|
# If the physical memory of the system is below 2GB it is wise to create a
|
|
# swap file. This will make the system more resiliant to memory spikes and
|
|
# prevent for instance spam filtering from crashing
|
|
|
|
# We will create a 1G file, this should be a good balance between disk usage
|
|
# and buffers for the system. We will only allocate this file if there is more
|
|
# than 5GB of disk space available
|
|
|
|
# The following checks are performed:
|
|
# - Check if swap is currently mountend by looking at /proc/swaps
|
|
# - Check if the user intents to activate swap on next boot by checking fstab entries.
|
|
# - Check if a swapfile already exists
|
|
# - Check if the root file system is not btrfs, might be an incompatible version with
|
|
# swapfiles. User should hanle it them selves.
|
|
# - Check the memory requirements
|
|
# - Check available diskspace
|
|
|
|
# See https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04
|
|
# for reference
|
|
|
|
SWAP_MOUNTED=$(cat /proc/swaps | tail -n+2)
|
|
SWAP_IN_FSTAB=$(grep "swap" /etc/fstab || /bin/true)
|
|
ROOT_IS_BTRFS=$(grep "\/ .*btrfs" /proc/mounts || /bin/true)
|
|
TOTAL_PHYSICAL_MEM=$(head -n 1 /proc/meminfo | awk '{print $2}' || /bin/true)
|
|
AVAILABLE_DISK_SPACE=$(df / --output=avail | tail -n 1)
|
|
if
|
|
[ -z "$SWAP_MOUNTED" ] &&
|
|
[ -z "$SWAP_IN_FSTAB" ] &&
|
|
[ ! -e /swapfile ] &&
|
|
[ -z "$ROOT_IS_BTRFS" ] &&
|
|
[ $TOTAL_PHYSICAL_MEM -lt 1900000 ] &&
|
|
[ $AVAILABLE_DISK_SPACE -gt 5242880 ]
|
|
then
|
|
echo "Adding a swap file to the system..."
|
|
|
|
# Allocate and activate the swap file. Allocate in 1KB chuncks
|
|
# doing it in one go, could fail on low memory systems
|
|
dd if=/dev/zero of=/swapfile bs=1024 count=$[1024*1024] status=none
|
|
if [ -e /swapfile ]; then
|
|
chmod 600 /swapfile
|
|
hide_output mkswap /swapfile
|
|
swapon /swapfile
|
|
fi
|
|
|
|
# Check if swap is mounted then activate on boot
|
|
if swapon -s | grep -q "\/swapfile"; then
|
|
echo "/swapfile none swap sw 0 0" >> /etc/fstab
|
|
else
|
|
echo "ERROR: Swap allocation failed"
|
|
fi
|
|
fi
|
|
|
|
# Certbot doesn't require a PPA in Debian
|
|
|
|
# ### Update Packages
|
|
|
|
# Update system packages to make sure we have the latest upstream versions
|
|
# of things from Ubuntu, as well as the directory of packages provide by the
|
|
# PPAs so we can install those packages later.
|
|
|
|
echo Updating system packages...
|
|
hide_output apt-get update
|
|
apt_get_quiet upgrade
|
|
|
|
# Old kernels pile up over time and take up a lot of disk space, and because of Mail-in-a-Box
|
|
# changes there may be other packages that are no longer needed. Clear out anything apt knows
|
|
# is safe to delete.
|
|
|
|
apt_get_quiet autoremove
|
|
|
|
# ### Install System Packages
|
|
|
|
# Install basic utilities.
|
|
#
|
|
# * haveged: Provides extra entropy to /dev/random so it doesn't stall
|
|
# when generating random numbers for private keys (e.g. during
|
|
# ldns-keygen).
|
|
# * unattended-upgrades: Apt tool to install security updates automatically.
|
|
# * cron: Runs background processes periodically.
|
|
# * ntp: keeps the system time correct
|
|
# * fail2ban: scans log files for repeated failed login attempts and blocks the remote IP at the firewall
|
|
# * netcat-openbsd: `nc` command line networking tool
|
|
# * git: we install some things directly from github
|
|
# * sudo: allows privileged users to execute commands as root without being root
|
|
# * coreutils: includes `nproc` tool to report number of processors, mktemp
|
|
# * bc: allows us to do math to compute sane defaults
|
|
# * openssh-client: provides ssh-keygen
|
|
|
|
echo Installing system packages...
|
|
apt_install python3 python3-dev python3-pip \
|
|
netcat-openbsd wget curl git sudo coreutils bc \
|
|
haveged pollinate openssh-client unzip \
|
|
unattended-upgrades cron ntp fail2ban rsyslog
|
|
|
|
# ### Suppress Upgrade Prompts
|
|
# When Ubuntu 20 comes out, we don't want users to be prompted to upgrade,
|
|
# because we don't yet support it.
|
|
if [ -f /etc/update-manager/release-upgrades ]; then
|
|
tools/editconf.py /etc/update-manager/release-upgrades Prompt=never
|
|
rm -f /var/lib/ubuntu-release-upgrader/release-upgrade-available
|
|
fi
|
|
|
|
# ### Set the system timezone
|
|
#
|
|
# Some systems are missing /etc/timezone, which we cat into the configs for
|
|
# Z-Push and ownCloud, so we need to set it to something. Daily cron tasks
|
|
# like the system backup are run at a time tied to the system timezone, so
|
|
# letting the user choose will help us identify the right time to do those
|
|
# things (i.e. late at night in whatever timezone the user actually lives
|
|
# in).
|
|
#
|
|
# However, changing the timezone once it is set seems to confuse fail2ban
|
|
# and requires restarting fail2ban (done below in the fail2ban
|
|
# section) and syslog (see #328). There might be other issues, and it's
|
|
# not likely the user will want to change this, so we only ask on first
|
|
# setup.
|
|
if [ -z "${NONINTERACTIVE:-}" ]; then
|
|
if [ ! -f /etc/timezone ] || [ ! -z ${FIRST_TIME_SETUP:-} ]; then
|
|
# If the file is missing or this is the user's first time running
|
|
# Mail-in-a-Box setup, run the interactive timezone configuration
|
|
# tool.
|
|
dpkg-reconfigure tzdata
|
|
restart_service rsyslog
|
|
fi
|
|
else
|
|
# This is a non-interactive setup so we can't ask the user.
|
|
# If /etc/timezone is missing, set it to UTC.
|
|
if [ ! -f /etc/timezone ]; then
|
|
echo "Setting timezone to UTC."
|
|
echo "Etc/UTC" > /etc/timezone
|
|
restart_service rsyslog
|
|
fi
|
|
fi
|
|
|
|
# ### Seed /dev/urandom
|
|
#
|
|
# /dev/urandom is used by various components for generating random bytes for
|
|
# encryption keys and passwords:
|
|
#
|
|
# * TLS private key (see `ssl.sh`, which calls `openssl genrsa`)
|
|
# * DNSSEC signing keys (see `dns.sh`)
|
|
# * our management server's API key (via Python's os.urandom method)
|
|
# * Roundcube's SECRET_KEY (`webmail.sh`)
|
|
#
|
|
# Why /dev/urandom? It's the same as /dev/random, except that it doesn't wait
|
|
# for a constant new stream of entropy. In practice, we only need a little
|
|
# entropy at the start to get going. After that, we can safely pull a random
|
|
# stream from /dev/urandom and not worry about how much entropy has been
|
|
# added to the stream. (http://www.2uo.de/myths-about-urandom/) So we need
|
|
# to worry about /dev/urandom being seeded properly (which is also an issue
|
|
# for /dev/random), but after that /dev/urandom is superior to /dev/random
|
|
# because it's faster and doesn't block indefinitely to wait for hardware
|
|
# entropy. Note that `openssl genrsa` even uses `/dev/urandom`, and if it's
|
|
# good enough for generating an RSA private key, it's good enough for anything
|
|
# else we may need.
|
|
#
|
|
# Now about that seeding issue....
|
|
#
|
|
# /dev/urandom is seeded from "the uninitialized contents of the pool buffers when
|
|
# the kernel starts, the startup clock time in nanosecond resolution,...and
|
|
# entropy saved across boots to a local file" as well as the order of
|
|
# execution of concurrent accesses to /dev/urandom. (Heninger et al 2012,
|
|
# https://factorable.net/weakkeys12.conference.pdf) But when memory is zeroed,
|
|
# the system clock is reset on boot, /etc/init.d/urandom has not yet run, or
|
|
# the machine is single CPU or has no concurrent accesses to /dev/urandom prior
|
|
# to this point, /dev/urandom may not be seeded well. After this, /dev/urandom
|
|
# draws from the same entropy sources as /dev/random, but it doesn't block or
|
|
# issue any warnings if no entropy is actually available. (http://www.2uo.de/myths-about-urandom/)
|
|
# Entropy might not be readily available because this machine has no user input
|
|
# devices (common on servers!) and either no hard disk or not enough IO has
|
|
# ocurred yet --- although haveged tries to mitigate this. So there's a good chance
|
|
# that accessing /dev/urandom will not be drawing from any hardware entropy and under
|
|
# a perfect-storm circumstance where the other seeds are meaningless, /dev/urandom
|
|
# may not be seeded at all.
|
|
#
|
|
# The first thing we'll do is block until we can seed /dev/urandom with enough
|
|
# hardware entropy to get going, by drawing from /dev/random. haveged makes this
|
|
# less likely to stall for very long.
|
|
|
|
echo Initializing system random number generator...
|
|
dd if=/dev/random of=/dev/urandom bs=1 count=32 2> /dev/null
|
|
|
|
# This is supposedly sufficient. But because we're not sure if hardware entropy
|
|
# is really any good on virtualized systems, we'll also seed from Ubuntu's
|
|
# pollinate servers:
|
|
|
|
pollinate -q -r
|
|
|
|
# Between these two, we really ought to be all set.
|
|
|
|
# We need an ssh key to store backups via rsync, if it doesn't exist create one
|
|
if [ ! -f /root/.ssh/id_rsa_miab ]; then
|
|
echo 'Creating SSH key for backup…'
|
|
ssh-keygen -t rsa -b 2048 -a 100 -f /root/.ssh/id_rsa_miab -N '' -q
|
|
fi
|
|
|
|
# ### Package maintenance
|
|
#
|
|
# Allow apt to install system updates automatically every day.
|
|
|
|
cat > /etc/apt/apt.conf.d/02periodic <<EOF;
|
|
APT::Periodic::MaxAge "7";
|
|
APT::Periodic::Update-Package-Lists "1";
|
|
APT::Periodic::Unattended-Upgrade "1";
|
|
APT::Periodic::Verbose "0";
|
|
EOF
|
|
|
|
# ### Firewall
|
|
|
|
# Various virtualized environments like Docker and some VPSs don't provide #NODOC
|
|
# a kernel that supports iptables. To avoid error-like output in these cases, #NODOC
|
|
# we skip this if the user sets DISABLE_FIREWALL=1. #NODOC
|
|
if [ -z "${DISABLE_FIREWALL:-}" ]; then
|
|
# Install `ufw` which provides a simple firewall configuration.
|
|
apt_install ufw
|
|
|
|
# ssh might be running on an alternate port. Use sshd -T to dump sshd's #NODOC
|
|
# settings, find the port it is supposedly running on, and open that port #NODOC
|
|
# too. #NODOC
|
|
SSH_PORT=$(sshd -T 2>/dev/null | grep "^port " | sed "s/port //") #NODOC
|
|
if [ ! -z "$SSH_PORT" ]; then
|
|
if [ "$SSH_PORT" != "22" ]; then
|
|
|
|
echo Opening alternate SSH port $SSH_PORT. #NODOC
|
|
ufw_limit $SSH_PORT #NODOC
|
|
else
|
|
# Allow incoming connections to SSH.
|
|
ufw_limit ssh;
|
|
fi
|
|
else
|
|
# Allow incoming connections to SSH.
|
|
ufw_limit ssh;
|
|
fi
|
|
|
|
ufw --force enable;
|
|
fi #NODOC
|
|
|
|
# ### Local DNS Service
|
|
|
|
# Install a local recursive DNS server --- i.e. for DNS queries made by
|
|
# local services running on this machine.
|
|
#
|
|
# (This is unrelated to the box's public, non-recursive DNS server that
|
|
# answers remote queries about domain names hosted on this box. For that
|
|
# see dns.sh.)
|
|
#
|
|
# The default systemd-resolved service provides local DNS name resolution. By default it
|
|
# is a recursive stub nameserver, which means it simply relays requests to an
|
|
# external nameserver, usually provided by your ISP or configured in /etc/systemd/resolved.conf.
|
|
#
|
|
# This won't work for us for three reasons.
|
|
#
|
|
# 1) We have higher security goals --- we want DNSSEC to be enforced on all
|
|
# DNS queries (some upstream DNS servers do, some don't).
|
|
# 2) We will configure postfix to use DANE, which uses DNSSEC to find TLS
|
|
# certificates for remote servers. DNSSEC validation *must* be performed
|
|
# locally because we can't trust an unencrypted connection to an external
|
|
# DNS server.
|
|
# 3) DNS-based mail server blacklists (RBLs) typically block large ISP
|
|
# DNS servers because they only provide free data to small users. Since
|
|
# we use RBLs to block incoming mail from blacklisted IP addresses,
|
|
# we have to run our own DNS server. See #1424.
|
|
#
|
|
# systemd-resolved has a setting to perform local DNSSEC validation on all
|
|
# requests (in /etc/systemd/resolved.conf, set DNSSEC=yes), but because it's
|
|
# a stub server the main part of a request still goes through an upstream
|
|
# DNS server, which won't work for RBLs. So we really need a local recursive
|
|
# nameserver.
|
|
#
|
|
# We'll install `bind9`, which as packaged for Ubuntu, has DNSSEC enabled by default via "dnssec-validation auto".
|
|
# We'll have it be bound to 127.0.0.1 so that it does not interfere with
|
|
# the public, recursive nameserver `nsd` bound to the public ethernet interfaces.
|
|
#
|
|
# About the settings:
|
|
#
|
|
# * Adding -4 to OPTIONS will have `bind9` not listen on IPv6 addresses
|
|
# so that we're sure there's no conflict with nsd, our public domain
|
|
# name server, on IPV6.
|
|
# * The listen-on directive in named.conf.options restricts `bind9` to
|
|
# binding to the loopback interface instead of all interfaces.
|
|
# * The max-recursion-queries directive increases the maximum number of iterative queries.
|
|
# If more queries than specified are sent, bind9 returns SERVFAIL. After flushing the cache during system checks,
|
|
# we ran into the limit thus we are increasing it from 75 (default value) to 100.
|
|
apt_install bind9
|
|
touch /etc/default/bind9
|
|
tools/editconf.py /etc/default/bind9 \
|
|
"OPTIONS=\"-u bind -4\""
|
|
if ! grep -q "listen-on " /etc/bind/named.conf.options; then
|
|
# Add a listen-on directive if it doesn't exist inside the options block.
|
|
sed -i "s/^}/\n\tlisten-on { 127.0.0.1; };\n}/" /etc/bind/named.conf.options
|
|
fi
|
|
if ! grep -q "max-recursion-queries " /etc/bind/named.conf.options; then
|
|
# Add a max-recursion-queries directive if it doesn't exist inside the options block.
|
|
sed -i "s/^}/\n\tmax-recursion-queries 100;\n}/" /etc/bind/named.conf.options
|
|
fi
|
|
|
|
# First we'll disable systemd-resolved's management of resolv.conf and its stub server.
|
|
# Breaking the symlink to /run/systemd/resolve/stub-resolv.conf means
|
|
# systemd-resolved will read it for DNS servers to use. Put in 127.0.0.1,
|
|
# which is where bind9 will be running. Obviously don't do this before
|
|
# installing bind9 or else apt won't be able to resolve a server to
|
|
# download bind9 from.
|
|
rm -f /etc/resolv.conf
|
|
tools/editconf.py /etc/systemd/resolved.conf DNSStubListener=no
|
|
echo "nameserver 127.0.0.1" > /etc/resolv.conf
|
|
|
|
# Restart the DNS services.
|
|
|
|
restart_service bind9
|
|
systemctl restart systemd-resolved
|
|
|
|
# ### Fail2Ban Service
|
|
|
|
# Configure the Fail2Ban installation to prevent dumb bruce-force attacks against dovecot, postfix, ssh, etc.
|
|
rm -f /etc/fail2ban/jail.local # we used to use this file but don't anymore
|
|
rm -f /etc/fail2ban/jail.d/defaults-debian.conf # removes default config so we can manage all of fail2ban rules in one config
|
|
cat conf/fail2ban/jails.conf \
|
|
| sed "s/PUBLIC_IP/$PUBLIC_IP/g" \
|
|
| sed "s/ADMIN_HOME_IP/$ADMIN_HOME_IP/g" \
|
|
| sed "s#STORAGE_ROOT#$STORAGE_ROOT#" \
|
|
> /etc/fail2ban/jail.d/00-mailinabox.conf
|
|
cp -f conf/fail2ban/filter.d/* /etc/fail2ban/filter.d/
|
|
cp -f conf/fail2ban/jail.d/* /etc/fail2ban/jail.d/
|
|
|
|
# fail2ban should be able to look back far enough because we increased findtime of recidive jail
|
|
tools/editconf.py /etc/fail2ban/fail2ban.conf dbpurgeage=7d
|
|
|
|
# On first installation, the log files that the jails look at don't all exist.
|
|
# e.g., The roundcube error log isn't normally created until someone logs into
|
|
# Roundcube for the first time. This causes fail2ban to fail to start. Later
|
|
# scripts will ensure the files exist and then fail2ban is given another
|
|
# restart at the very end of setup.
|
|
restart_service fail2ban
|