calico

• Radxa Rock Pi S

• Ubuntu 20.04 (custom Radxa 4.4 kernel)

  Linux calico.thighhighs.top 4.4.143-65-rockchip-g58431d38f8f3 #1 SMP PREEMPT Sat Aug 14 09:31:07 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux

• Located at home

Build notes

Used this to write the general guide for Rock Pi S hardware.

Image and setup SSH keys

• Image the SD card and let it boot, it'll get on the network with DHCP

• Copy your SSH key, the password is rock

  ssh-copy-id rock@IP

• Login again, now it'll use your SSH key

  ssh rock@IP

• Set a strong random password, this will be used for both rock and root

  passwd

• Sudo up and set the same password for root

  sudo -i
  passwd

  Record the new password somewhere safe

• Lock the rock account now, note that this still permits key access

  usermod -L rock

• Grab the rock user's authorized_keys so root can use it

  mkdir -m 0700 /root/.ssh
  cp /home/rock/.ssh/authorized_keys /root/.ssh/
  chown root:root /root/.ssh/authorized_keys ; chmod 0600 /root/.ssh/authorized_keys

• Regenerate SSH host keys, we don't know what was installed with the OS image

  rm /etc/ssh/ssh_host_*
  dpkg-reconfigure openssh-server

  • You could do ssh-keygen -A as an alternative, but it'll generate DSA keys as well which we don't want

• Logout completely
• Delete the entries from your known_hosts file
• SSH again as root@IP, accepting the new keys. It'll use your SSH key instead of asking for password now.

Basic environment stuff

• Set hostname:

  hostnamectl set-hostname calico.thighhighs.top

• Update hostname in /etc/hosts
• Uncomment the IPv6 entries in /etc/hosts as well

• Set timezone

  timedatectl set-timezone Australia/Sydney

• Set editor

  echo "export EDITOR=vim" > /etc/profile.d/editor-vim.sh

• Disable HashKnownHosts

  echo -e "Host *\n    HashKnownHosts no" > /etc/ssh/ssh_config.d/99-global.conf

• Configure screen

  curl -o ~/.screenrc https://gist.githubusercontent.com/barneydesmond/d16c5201ed9d2280251dfca7c620bb86/raw/.screenrc

• Configure top by entering this cheatcode

  z x c b s 1.5 <Enter>
  e <zero> 1 W q

• Disable wifi and bluetooth, we don't need them and it slows down boot

  systemctl disable wpa_supplicant.service --now
  systemctl disable bluetooth.service --now
  systemctl disable rtl8723ds-btfw-load.service --now
  
  echo -e "# Don't load the WLAN+BT module, we don't need it\nblacklist rtl8723ds" > /etc/modprobe.d/blacklist-radios.conf
  update-initramfs -u

• Install useful packages

  apt update
  apt install -y vim screen bash-completion lsof tcpdump netcat strace nmap less bsdmainutils tzdata whiptail netbase wget curl python-is-python3 net-tools ack jq make elinks nmap whois ethtool bind9-dnsutils apt-utils man-db

• Do a full upgrade then reboot

  apt full-upgrade
  reboot

Configure networking

What we want:

• Static IPv4 addressing
• Autoconfig dynamic IPv6 addressing
  • Global stable IPv6 addresses (I guess)
• Add a locally-defined static IPv6 address, that other hosts can refer to via DNS etc
• DNS resolvers will be manually defined

We'll use netplan to do this, as it greatly simplifies getting what we want without needing to faff around with config in multiple places.

• Disable IPv6 privacy addresses, they're enabled by default on Ubuntu

  sed -r -i 's/tempaddr = 2/tempaddr = 0/' /etc/sysctl.d/10-ipv6-privacy.conf
  systemctl restart procps

  This is a nifty site for testing: http://ip.bieringer.net/ - Look at EUI64_SCOPE and see if it's random/privacy/global. Global is probably what we want for servers.

• Install netplan

  apt install -y netplan.io

• Remove network-manager, we want to use networkd instead

  apt purge network-manager networkmanager-patch
  rm -rf /etc/NetworkManager/
  apt autoremove

• Write the network config in /etc/netplan/10-thighhighs.yaml

  network:
      version: 2
      renderer: networkd
  
      ethernets:
          eth0:
              critical: true
              dhcp-identifier: mac
              dhcp4: false
              dhcp6: true
              dhcp6-overrides:
                  use-dns: false
              ipv6-privacy: false
              addresses:
                  - "192.168.1.26/24"
                  # :1:26 for the .1.26 IPv4, ca6c == 51820, the default Wireguard port
                  - "2404:e80:42e3:0:26:0:0:ca6c/64"
              routes:
                  - to: 0.0.0.0/0
                    via: 192.168.1.1
                    on-link: true
              nameservers:
                  addresses:
                      - 192.168.1.20
                      - 192.168.1.24
                      - fe80::e65f:1ff:fe1c:c6ea
                      - fe80::ba27:ebff:fe8c:f4f8
                  search:
                      - thighhighs.top

• Sanity check the generated config, hope it doesn't complain

  netplan generate
  netplan apply

• Reboot and cross your fingers

Save a known-good image for convenience

On another system with an SD card reader, take an image of the system after shrinking the filesystem

e2fsck -f /dev/mmcblk0p2
resize2fs -M /dev/mmcblk0p2

# Use cfdisk or parted to shrink the partition to a bit larger than the FS, has just been reported.
# In this case it's just over 1GiB, so I'll shrink the partition to 1.1GiB.

# Now take the image, capture a bit more than the size of the partitions.
# boot+root partitions are ~1.22GiB (1254MiB) here, so I'll capture 1300MiB just to be sure.
dd bs=1M count=1300 if=/dev/mmcblk0 | pv -br | gzip --fast > 2021-12-13_calico_img_clean_os.img.gz

If you ever need to restore this image, make sure to run resize-assistant afterwards. As well as growing the FS, it needs to locate the backup GPT table at the end of the disk. At the very least you need to run sgdisk -e /dev/mmcblk0 and then partprobe to clean that up.

If you want to expand the filesystem manually:

1. Boot the image you just restored to the SD card

2. sgdisk -e /dev/mmcblk0

3. partprobe

4. Use parted or cfdisk to expand the 2nd partition to the desired size (or the whole disk)

5. resize2fs /dev/mmcblk0p2

Pihole

Straightforward basic install, no conflict with other installed services.

• curl -sSL https://install.pi-hole.net | bash

• Cloudflare upstream
• Web interface enabled, full query logging and display
• Pi-hole DNS (IPv4): 192.168.1.26
• Pi-hole DNS (IPv6): 2404:e80:42e3:0:1:26:0:ca6c

Admin UI at https://calico.thighhighs.top/admin/

Should probably put cloudflare resolvers into the systemwide resolver set, meaning we don't see our own records though.

• 1.1.1.1
• 1.0.0.1
• 2606:4700:4700::1111
• 2606:4700:4700::1001

Can add TLS \o/ https://discourse.pi-hole.net/t/enabling-https-for-your-pi-hole-web-interface/5771/17

Firewall

As per https://docs.pi-hole.net/main/prerequisites/ I've installed ufw and locked things down.

Limit and fail2ban would be good to do as well: https://www.raspberrypi.org/documentation/configuration/security.md

apt install ufw
ufw allow ssh
ufw enable

# Pihole stuff - https://docs.pi-hole.net/main/prerequisites/#ufw
ufw allow http
ufw allow https
ufw allow domain
ufw allow 67/udp
ufw allow 67/tcp
ufw allow 546:547/udp