119 lines
4.4 KiB
Bash
Executable File
119 lines
4.4 KiB
Bash
Executable File
source setup/functions.sh # load our functions
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# Basic System Configuration
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# -------------------------
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# ### Install Packages
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# Update system packages to make sure we have the latest upstream versions of things from Ubuntu.
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echo Updating system packages...
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hide_output apt-get update
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apt_get_quiet upgrade
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# Install basic utilities.
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#
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# * haveged: Provides extra entropy to /dev/random so it doesn't stall
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# when generating random numbers for private keys (e.g. during
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# ldns-keygen).
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# * unattended-upgrades: Apt tool to install security updates automatically.
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# * cron: Runs background processes periodically.
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# * ntp: keeps the system time correct
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# * fail2ban: scans log files for repeated failed login attempts and blocks the remote IP at the firewall
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# * gpg: used by upgrade.sh to verify the Mail-in-a-Box tag signature, also by duplicity to make backups
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# * git: we install some things directly from github
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# * sudo: allows privileged users to execute commands as root without being root
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# * coreutils: includes `nproc` tool to report number of processors
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# * bc: allows us to do math to compute sane defaults
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apt_install python3 python3-dev python3-pip \
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wget curl gpg git sudo coreutils bc \
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haveged unattended-upgrades cron ntp fail2ban
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# Allow apt to install system updates automatically every day.
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cat > /etc/apt/apt.conf.d/02periodic <<EOF;
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APT::Periodic::MaxAge "7";
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APT::Periodic::Update-Package-Lists "1";
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APT::Periodic::Unattended-Upgrade "1";
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APT::Periodic::Verbose "1";
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EOF
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# ### Firewall
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# Various virtualized environments like Docker and some VPSs don't provide #NODOC
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# a kernel that supports iptables. To avoid error-like output in these cases, #NODOC
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# we skip this if the user sets DISABLE_FIREWALL=1. #NODOC
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if [ -z "$DISABLE_FIREWALL" ]; then
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# Install `ufw` which provides a simple firewall configuration.
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apt_install ufw
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# Allow incoming connections to SSH.
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ufw_allow ssh;
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# ssh might be running on an alternate port. Use sshd -T to dump sshd's #NODOC
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# settings, find the port it is supposedly running on, and open that port #NODOC
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# too. #NODOC
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SSH_PORT=$(sshd -T 2>/dev/null | grep "^port " | sed "s/port //") #NODOC
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if [ ! -z "$SSH_PORT" ]; then
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if [ "$SSH_PORT" != "22" ]; then
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echo Opening alternate SSH port $SSH_PORT. #NODOC
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ufw_allow $SSH_PORT #NODOC
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fi
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fi
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ufw --force enable;
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fi #NODOC
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# ### Local DNS Service
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# Install a local DNS server, rather than using the DNS server provided by the
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# ISP's network configuration.
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#
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# We do this to ensure that DNS queries
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# that *we* make (i.e. looking up other external domains) perform DNSSEC checks.
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# We could use Google's Public DNS, but we don't want to create a dependency on
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# Google per our goals of decentralization. `bind9`, as packaged for Ubuntu, has
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# DNSSEC enabled by default via "dnssec-validation auto".
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#
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# So we'll be running `bind9` bound to 127.0.0.1 for locally-issued DNS queries
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# and `nsd` bound to the public ethernet interface for remote DNS queries asking
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# about our domain names. `nsd` is configured later.
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#
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# About the settings:
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#
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# * RESOLVCONF=yes will have `bind9` take over /etc/resolv.conf to tell
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# local services that DNS queries are handled on localhost.
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# * Adding -4 to OPTIONS will have `bind9` not listen on IPv6 addresses
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# so that we're sure there's no conflict with nsd, our public domain
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# name server, on IPV6.
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# * The listen-on directive in named.conf.options restricts `bind9` to
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# binding to the loopback interface instead of all interfaces.
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apt_install bind9 resolvconf
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tools/editconf.py /etc/default/bind9 \
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RESOLVCONF=yes \
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"OPTIONS=\"-u bind -4\""
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if ! grep -q "listen-on " /etc/bind/named.conf.options; then
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# Add a listen-on directive if it doesn't exist inside the options block.
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sed -i "s/^}/\n\tlisten-on { 127.0.0.1; };\n}/" /etc/bind/named.conf.options
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fi
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if [ -f /etc/resolvconf/resolv.conf.d/original ]; then
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echo "Archiving old resolv.conf (was /etc/resolvconf/resolv.conf.d/original, now /etc/resolvconf/resolv.conf.original)." #NODOC
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mv /etc/resolvconf/resolv.conf.d/original /etc/resolvconf/resolv.conf.original #NODOC
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fi
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# Restart the DNS services.
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restart_service bind9
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restart_service resolvconf
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# ### Fail2Ban Service
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# Configure the Fail2Ban installation to prevent dumb bruce-force attacks against dovecot, postfix and ssh
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cp conf/fail2ban/jail.local /etc/fail2ban/jail.local
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cp conf/fail2ban/dovecotimap.conf /etc/fail2ban/filter.d/dovecotimap.conf
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restart_service fail2ban
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