183 lines
9.9 KiB
Bash
183 lines
9.9 KiB
Bash
#!/usr/bin/env bash
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# ──────────────────────────────────────────────────────────────────────────────
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# Secure‑SSH Setup – Modern Linux (2025‑edition, PAM‑aware)
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# ----------------------------------------------------------
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# ✦ Generates hardened OpenSSH config (IPv4‑only)
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# ✦ Installs / updates OpenSSH‑server + creates host keys
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# ✦ Creates users, adds SSH public keys, restricts login
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# ✦ Removes deprecated directives – fully OpenSSH ≥9.x compliant
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# ✦ Dynamically omits UsePAM if PAM isn’t present (e.g. Alpine)
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# ✦ Adds post‑quantum KEX, minimal cipher suite, strict auth‑flow,
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# rate‑limiting & root lockdown
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# ──────────────────────────────────────────────────────────────────────────────
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printf "\033c" # clear terminal
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SSH_CONFIG_DIR="/etc/ssh/sshd_config.d"
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SSH_MAIN_CONFIG="/etc/ssh/sshd_config"
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SSH_CONFIG_FILE="$SSH_CONFIG_DIR/secure.conf"
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ED25519_KEY="/etc/ssh/ssh_host_ed25519_key"
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ECDSA_KEY="/etc/ssh/ssh_host_ecdsa_key"
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# ─── ANSI colors ──────────────────────────────────────────────────────────────
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RED='\033[1;31m'; GREEN='\033[1;32m'; YELLOW='\033[1;33m'; BLUE='\033[1;34m'; WHITE='\033[1;37m'; RESET='\033[0m'
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log() { echo -e "${GREEN}$1${RESET}"; }
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warn() { echo -e "${YELLOW}$1${RESET}"; }
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error() { echo -e "${RED}$1${RESET}"; }
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# ─── Service‑manager detection ───────────────────────────────────────────────
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detect_service_manager() {
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if command -v systemctl &>/dev/null; then echo systemd
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elif command -v rc-service &>/dev/null; then echo openrc # Alpine, Gentoo…
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elif command -v service &>/dev/null; then echo sysvinit
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else echo unknown; fi
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}
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# ─── SSH service‑name detection ───────────────────────────────────────────────
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detect_ssh_service() {
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local manager=$1 services=(sshd ssh openssh-server openssh)
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case $manager in
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systemd)
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for s in "${services[@]}"; do systemctl list-units --type=service | grep -q "^$s" && { echo $s; return; }; done ;;
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openrc)
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for s in "${services[@]}"; do rc-service -l | grep -q "^$s$" && { echo $s; return; }; done ;;
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sysvinit)
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for s in "${services[@]}"; do [ -x "/etc/init.d/$s" ] && { echo $s; return; }; done ;;
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esac
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[ -x /usr/sbin/sshd ] && echo sshd || echo unknown
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}
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restart_ssh_service() {
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local manager=$1 service=$2; warn "Starte SSH‑Dienst ($service) neu…"
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case $manager in
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systemd) sudo systemctl restart "$service" && return 0 ;;
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openrc) sudo rc-service "$service" restart && return 0 ;;
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sysvinit) sudo "/etc/init.d/$service" restart 2>/dev/null && return 0 ;;
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esac
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sudo killall -HUP sshd 2>/dev/null && return 0
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return 1
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}
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install_package() {
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local p=$1; warn "Installiere $p…"
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if command -v apt &>/dev/null; then sudo apt update -qq && sudo apt install -y $p -qq
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elif command -v dnf &>/dev/null; then sudo dnf install -y $p &>/dev/null
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elif command -v yum &>/dev/null; then sudo yum install -y $p &>/dev/null
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elif command -v apk &>/dev/null; then sudo apk add $p &>/dev/null
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elif command -v pacman &>/dev/null; then sudo pacman -Sy --noconfirm $p &>/dev/null
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elif command -v zypper &>/dev/null; then sudo zypper install -y $p &>/dev/null
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else error "Paketmanager nicht erkannt – installiere $p manuell."; return 1; fi
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log "$p installiert."
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}
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# ─── Preparations ─────────────────────────────────────────────────────────────
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SERVICE_MANAGER=$(detect_service_manager); log "Service‑Manager: $SERVICE_MANAGER"
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command -v sudo &>/dev/null || { warn "sudo fehlt – Installation…"; install_package sudo; }
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command -v sshd &>/dev/null || install_package openssh-server
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[ -d "$SSH_CONFIG_DIR" ] || { warn "Erstelle $SSH_CONFIG_DIR"; sudo mkdir -p "$SSH_CONFIG_DIR"; }
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# ─── Host keys ────────────────────────────────────────────────────────────────
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for entry in "$ED25519_KEY ed25519" "$ECDSA_KEY ecdsa -b 384"; do
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set -- $entry; key=$1; shift; args=$*
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[ -f "$key" ] || { warn "Generiere Host-Key $(basename $key)…"; sudo ssh-keygen -t $args -f "$key" -N "" -q && sudo chmod 600 "$key" && log "Key erstellt."; }
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done
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# ─── Replace main config with include only ────────────────────────────────────
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warn "Setze $SSH_MAIN_CONFIG auf Include…"
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echo "Include $SSH_CONFIG_DIR/*.conf" | sudo tee "$SSH_MAIN_CONFIG" >/dev/null
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sudo rm -f $SSH_CONFIG_DIR/*
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# ─── User handling ────────────────────────────────────────────────────────────
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read -rp $'\e[1;34mWelche Benutzer dürfen sich per SSH anmelden? (Leerzeichen-getrennt): \e[0m' SSH_USERS
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VALID_USERS=""
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# distribution‑specific sudo group
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declare -A distro_sudo=( [ubuntu]=sudo [debian]=sudo [raspbian]=sudo [centos]=wheel [fedora]=wheel [rhel]=wheel [almalinux]=wheel [rocky]=wheel [ol]=wheel [arch]=wheel [manjaro]=wheel [alpine]=wheel )
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SUDO_GROUP=sudo; [ -f /etc/os-release ] && { . /etc/os-release; SUDO_GROUP=${distro_sudo[$ID]:-sudo}; }
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log "Benutze sudo-Gruppe: $SUDO_GROUP"
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for u in $SSH_USERS; do
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if id "$u" &>/dev/null; then log "Benutzer $u existiert."; VALID_USERS+="$u "; continue; fi
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read -rp $'\e[1;34mBenutzer '"$u"$' anlegen? [y/N]: \e[0m' create; [[ $create =~ ^[Yy]$ ]] || continue
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read -rsp $'\e[1;34mPasswort für '"$u"$': \e[0m' pw; echo
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sudo useradd -m -s /bin/bash "$u" && echo "$u:$pw" | sudo chpasswd
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sudo usermod -aG "$SUDO_GROUP" "$u"
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sudo install -d -m700 -o "$u" -g "$u" "/home/$u/.ssh"
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sudo touch "/home/$u/.ssh/authorized_keys" && sudo chmod 600 "/home/$u/.ssh/authorized_keys" && sudo chown "$u":"$u" "/home/$u/.ssh/authorized_keys"
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read -rp $'\e[1;34mSSH Public Key für '"$u"$' hinzufügen? [y/N]: \e[0m' addkey
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if [[ $addkey =~ ^[Yy]$ ]]; then read -rp $'\e[1;34mPublic Key: \e[0m' key; echo "$key" | sudo tee -a "/home/$u/.ssh/authorized_keys" >/dev/null; fi
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VALID_USERS+="$u "
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done
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# ─── SFTP binary discovery ───────────────────────────────────────────────────
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for p in /usr/lib/openssh/sftp-server /usr/libexec/openssh/sftp-server /usr/lib/ssh/sftp-server; do [ -x "$p" ] && SFTP_PATH=$p && break; done
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SFTP_PATH=${SFTP_PATH:-internal-sftp}; log "SFTP-Pfad: $SFTP_PATH"
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# ─── PAM detection ────────────────────────────────────────────────────────────
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PAM_AVAILABLE=false
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[ -d /etc/pam.d ] && { find / -maxdepth 2 -name 'libpam.so*' -quit | grep -q libpam && PAM_AVAILABLE=true; }
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$PAM_AVAILABLE && log "PAM verfügbar." || warn "PAM nicht gefunden – UsePAM wird ausgelassen."
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# ─── Generate secure.conf ─────────────────────────────────────────────────────
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warn "Erstelle $SSH_CONFIG_FILE (modern hardened)…"
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sudo tee "$SSH_CONFIG_FILE" >/dev/null <<EOF
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# ─────────────────────────────────────────────────────────────────────────────
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# Generated $(date -u +'%Y-%m-%dT%H:%MZ')
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# ─────────────────────────────────────────────────────────────────────────────
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AddressFamily inet
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Port 22
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HostKey $ED25519_KEY
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HostKey $ECDSA_KEY
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KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,diffie-hellman-group14-sha256
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Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes256-ctr
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MACs hmac-sha2-512,hmac-sha2-256
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SyslogFacility AUTHPRIV
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LogLevel VERBOSE
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MaxStartups 10:30:100
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LoginGraceTime 30s
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PermitRootLogin no
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PermitEmptyPasswords no
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IgnoreRhosts yes
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StrictModes yes
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PubkeyAuthentication yes
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PasswordAuthentication no
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KbdInteractiveAuthentication no
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AuthenticationMethods publickey
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# X11 & SFTP
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X11Forwarding no
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Subsystem sftp $SFTP_PATH
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ClientAliveInterval 300
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ClientAliveCountMax 2
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AllowUsers ${VALID_USERS%% }
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EOF
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# Append PAM directives only if available
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if $PAM_AVAILABLE; then
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printf '\nUsePAM yes\nPrintMotd no\n' | sudo tee -a "$SSH_CONFIG_FILE" >/dev/null
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fi
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log "Secure‑Config geschrieben."
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# ─── Validate & restart SSH ──────────────────────────────────────────────────
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[ -d /run/sshd ] || { sudo mkdir -p /run/sshd; sudo chmod 0755 /run/sshd; }
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sudo sshd -t || { error "SSH-Konfiguration ungültig!"; exit 1; }
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SSH_SERVICE=$(detect_ssh_service "$SERVICE_MANAGER")
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[ "$SSH_SERVICE" = unknown ] && { error "SSH-Dienst nicht gefunden."; exit 1; }
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restart_ssh_service "$SERVICE_MANAGER" "$SSH_SERVICE" || { error "Neustart fehlgeschlagen – manuell prüfen."; exit 1; }
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log "Setup abgeschlossen. Zugelassene Benutzer: ${WHITE}${VALID_USERS}${RESET}"
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