167 lines
6.4 KiB
Bash
Executable File
167 lines
6.4 KiB
Bash
Executable File
#!/bin/bash
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#
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# .---. . .
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# | | |
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# |--- .--. .-. .-. .-.| .-. .--.--. |.-. .-. .--. .-.
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# | | (.-' (.-' ( | ( )| | | | )( )| | (.-'
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# ' ' --' --' -' - -' ' ' -' -' -' ' - --'
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#
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# Freedom in the Cloud
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#
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# ssh functions
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#
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# License
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# =======
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#
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# Copyright (C) 2014-2016 Bob Mottram <bob@freedombone.net>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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SSH_PORT=2222
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# Settings from bettercrypto.org
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SSH_CIPHERS="aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes128-ctr"
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SSH_MACS="hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160"
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SSH_KEX="diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1"
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SSH_HOST_KEY_ALGORITHMS="ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-ed25519,ssh-rsa"
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function configure_ssh {
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if [[ $(is_completed $FUNCNAME) == "1" ]]; then
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return
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fi
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sed -i "s/Port .*/Port $SSH_PORT/g" /etc/ssh/sshd_config
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sed -i 's/PermitRootLogin.*/PermitRootLogin no/g' /etc/ssh/sshd_config
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sed -i 's/X11Forwarding.*/X11Forwarding no/g' /etc/ssh/sshd_config
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sed -i 's/ServerKeyBits.*/ServerKeyBits 4096/g' /etc/ssh/sshd_config
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sed -i 's/TCPKeepAlive.*/TCPKeepAlive no/g' /etc/ssh/sshd_config
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sed -i 's|HostKey /etc/ssh/ssh_host_dsa_key|#HostKey /etc/ssh/ssh_host_dsa_key|g' /etc/ssh/sshd_config
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sed -i 's|HostKey /etc/ssh/ssh_host_ecdsa_key|#HostKey /etc/ssh/ssh_host_ecdsa_key|g' /etc/ssh/sshd_config
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if ! grep -q 'DebianBanner' /etc/ssh/sshd_config; then
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echo 'DebianBanner no' >> /etc/ssh/sshd_config
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else
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sed -i 's|DebianBanner.*|DebianBanner no|g' /etc/ssh/sshd_config
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fi
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if grep -q 'ClientAliveInterval' /etc/ssh/sshd_config; then
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sed -i 's/ClientAliveInterval.*/ClientAliveInterval 60/g' /etc/ssh/sshd_config
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else
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echo 'ClientAliveInterval 60' >> /etc/ssh/sshd_config
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fi
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if grep -q 'ClientAliveCountMax' /etc/ssh/sshd_config; then
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sed -i 's/ClientAliveCountMax.*/ClientAliveCountMax 3/g' /etc/ssh/sshd_config
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else
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echo 'ClientAliveCountMax 3' >> /etc/ssh/sshd_config
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fi
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if grep -q 'Ciphers' /etc/ssh/sshd_config; then
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sed -i "s|Ciphers.*|Ciphers $SSH_CIPHERS|g" /etc/ssh/sshd_config
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else
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echo "Ciphers $SSH_CIPHERS" >> /etc/ssh/sshd_config
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fi
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if grep -q 'MACs' /etc/ssh/sshd_config; then
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sed -i "s|MACs.*|MACs $SSH_MACS|g" /etc/ssh/sshd_config
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else
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echo "MACs $SSH_MACS" >> /etc/ssh/sshd_config
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fi
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if grep -q 'KexAlgorithms' /etc/ssh/sshd_config; then
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sed -i "s|KexAlgorithms.*|KexAlgorithms $SSH_KEX|g" /etc/ssh/sshd_config
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else
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echo "KexAlgorithms $SSH_KEX" >> /etc/ssh/sshd_config
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fi
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apt-get -yq install fail2ban vim-common
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function_check configure_firewall_for_ssh
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configure_firewall_for_ssh
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mark_completed $FUNCNAME
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}
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# see https://stribika.github.io/2015/01/04/secure-secure-shell.html
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function ssh_remove_small_moduli {
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awk '$5 > 2000' /etc/ssh/moduli > ~/moduli
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mv ~/moduli /etc/ssh/moduli
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}
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function configure_ssh_client {
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if [[ $(is_completed $FUNCNAME) == "1" ]]; then
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return
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fi
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#sed -i 's/# PasswordAuthentication.*/ PasswordAuthentication no/g' /etc/ssh/ssh_config
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#sed -i 's/# ChallengeResponseAuthentication.*/ ChallengeResponseAuthentication no/g' /etc/ssh/ssh_config
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sed -i "s/# HostKeyAlgorithms.*/ HostKeyAlgorithms $SSH_HOST_KEY_ALGORITHMS/g" /etc/ssh/ssh_config
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sed -i "s/# Ciphers.*/ Ciphers $SSH_CIPHERS/g" /etc/ssh/ssh_config
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sed -i "s/# MACs.*/ MACs $SSH_MACS/g" /etc/ssh/ssh_config
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if ! grep -q "HostKeyAlgorithms" /etc/ssh/ssh_config; then
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echo " HostKeyAlgorithms $SSH_HOST_KEY_ALGORITHMS" >> /etc/ssh/ssh_config
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fi
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sed -i "s/Ciphers.*/Ciphers $SSH_CIPHERS/g" /etc/ssh/ssh_config
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if ! grep -q "Ciphers " /etc/ssh/ssh_config; then
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echo " Ciphers $SSH_CIPHERS" >> /etc/ssh/ssh_config
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fi
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sed -i "s/MACs.*/MACs $SSH_MACS/g" /etc/ssh/ssh_config
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if ! grep -q "MACs " /etc/ssh/ssh_config; then
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echo " MACs $SSH_MACS" >> /etc/ssh/ssh_config
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fi
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# Create ssh keys
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if [ ! -f ~/.ssh/id_ed25519 ]; then
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ssh-keygen -t ed25519 -o -a 100
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fi
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if [ ! -f ~/.ssh/id_rsa ]; then
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ssh-keygen -t rsa -b 4096 -o -a 100
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fi
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function_check ssh_remove_small_moduli
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ssh_remove_small_moduli
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mark_completed $FUNCNAME
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}
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function regenerate_ssh_keys {
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if [[ $(is_completed $FUNCNAME) == "1" ]]; then
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return
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fi
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rm -f /etc/ssh/ssh_host_*
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dpkg-reconfigure openssh-server
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function_check ssh_remove_small_moduli
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ssh_remove_small_moduli
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systemctl restart ssh
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mark_completed $FUNCNAME
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}
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function configure_firewall_for_ssh {
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if [[ $(is_completed $FUNCNAME) == "1" ]]; then
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return
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fi
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if [[ $INSTALLED_WITHIN_DOCKER == "yes" ]]; then
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# docker does its own firewalling
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return
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fi
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firewall_add SSH ${SSH_PORT} tcp
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mark_completed $FUNCNAME
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}
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function get_ssh_server_key {
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if [ -f /etc/ssh/ssh_host_rsa_key.pub ]; then
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echo "RSA Md5: $(ssh-keygen -lf /etc/ssh/ssh_host_rsa_key.pub | awk -F ' ' '{print $2}')"
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echo "RSA SHA256: $(awk '{print $2}' /etc/ssh/ssh_host_rsa_key.pub | base64 -d | sha256sum -b | awk '{print $1}' | xxd -r -p | base64 | sed 's|=||g')"
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fi
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if [ -f /etc/ssh/ssh_host_ed25519_key.pub ]; then
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echo "ED25519 Md5: $(ssh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub | awk -F ' ' '{print $2}')"
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echo "ED25519 SHA256:$(awk '{print $2}' /etc/ssh/ssh_host_ed25519_key.pub | base64 -d | sha256sum -b | awk '{print $1}' | xxd -r -p | base64 | sed 's|=||g')"
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fi
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}
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# NOTE: deliberately no exit 0
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