prole/etc/init_kdc.sh

#!/usr/bin/env bash

set -euo pipefail

# init_kdc.sh
# Purpose:
# - Provision the in-cluster Prole KDC (MIT Kerberos) in the common services namespace
# - Optionally configure cross-realm trust to an external realm when credentials are provided
#
# Usage:
#   ./init_kdc.sh initialize|update   # create/update KDC resources
#   ./init_kdc.sh status              # show KDC status
#   ./init_kdc.sh cleanup             # remove KDC resources

SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)

# shellcheck disable=SC1090
source "$SCRIPT_DIR/prole_cfg.sh"

if [[ "${1:-}" == "--mode" || "${1:-}" == "-m" ]]; then
  prole_set_mode "${2:-}"
  shift 2
elif [[ "${1:-}" == --mode=* || "${1:-}" == -m=* ]]; then
  prole_set_mode "${1#*=}"
  shift
fi

prole_ensure_kubeconfig >/dev/null 2>&1 || true

ACTION=${1:-initialize}

KDC_NAMESPACE=${PROLE_KDC_NAMESPACE:-${SERVICE_NAMESPACE:-${NAMESPACE:-default}}}
PROLE_KDC_ENABLED=${PROLE_KDC_ENABLED:-1}
PROLE_KDC_NAME=${PROLE_KDC_NAME:-dog}
PROLE_KDC_SERVICE=${PROLE_KDC_SERVICE:-authority}
PROLE_KDC_IMAGE=${PROLE_KDC_IMAGE:-}
PROLE_KDC_IMAGE_NAME=${PROLE_KDC_IMAGE_NAME:-prole-authority}
PROLE_KDC_IMAGE_TAG=${PROLE_KDC_IMAGE_TAG:-latest}
PROLE_KDC_REGISTRY_HOST=${PROLE_KDC_REGISTRY_HOST:-${LOCAL_REGISTRY:-localhost:5000}}
PROLE_KDC_REGISTRY_INTERNAL=${PROLE_KDC_REGISTRY_INTERNAL:-${LOCAL_REGISTRY_INTERNAL:-}}
PROLE_KDC_BUILD_IMAGE=${PROLE_KDC_BUILD_IMAGE:-1}
PROLE_KDC_REALM=${PROLE_KDC_REALM:-}
PROLE_KDC_DOMAIN=${PROLE_KDC_DOMAIN:-}
PROLE_KDC_ADMIN_PRINCIPAL=${PROLE_KDC_ADMIN_PRINCIPAL:-admin/admin}
PROLE_KDC_ADMIN_PASSWORD=${PROLE_KDC_ADMIN_PASSWORD:-}
PROLE_KDC_MASTER_PASSWORD=${PROLE_KDC_MASTER_PASSWORD:-}
PROLE_KDC_TRUST_REALM=${PROLE_KDC_TRUST_REALM:-${KRB5_REALM:-}}
PROLE_KDC_TRUST_ADMIN=${PROLE_KDC_TRUST_ADMIN:-${KRB5_USER:-}}
PROLE_KDC_TRUST_PASSWORD=${PROLE_KDC_TRUST_PASSWORD:-${KRB5_PASSWORD:-}}
PROLE_KDC_TRUST_SHARED_PASSWORD=${PROLE_KDC_TRUST_SHARED_PASSWORD:-}
KRB5_KDC=${KRB5_KDC:-}
KRB5_ADMIN=${KRB5_ADMIN:-}

log() { printf '%s\n' "$*"; }
err() { printf '%s\n' "$*" >&2; }

ensure_tools() {
  for t in kubectl; do
    command -v "$t" >/dev/null || { err "Missing required tool: $t"; exit 1; }
  done
}

ensure_docker() {
  command -v docker >/dev/null || { err "Missing required tool: docker"; exit 1; }
  if ! docker info >/dev/null 2>&1; then
    err "Docker is not running or not accessible."
    exit 1
  fi
}

ensure_namespace() {
  if ! kubectl get namespace "$KDC_NAMESPACE" >/dev/null 2>&1; then
    log "Creating namespace '$KDC_NAMESPACE' ..."
    kubectl create namespace "$KDC_NAMESPACE" >/dev/null 2>&1 || true
  fi
}

lowercase() {
  printf '%s' "${1:-}" | tr '[:upper:]' '[:lower:]'
}

registry_host_from_url() {
  local value="${1:-}"
  value="${value#http://}"
  value="${value#https://}"
  value="${value%%/*}"
  value="${value%%:*}"
  printf '%s' "$value"
}

gen_password() {
  if command -v openssl >/dev/null 2>&1; then
    openssl rand -base64 18
    return 0
  fi
  if command -v python3 >/dev/null 2>&1; then
    python3 - <<'PY'
import secrets, string
alphabet = string.ascii_letters + string.digits
print(''.join(secrets.choice(alphabet) for _ in range(24)))
PY
    return 0
  fi
  date +%s
}

b64_decode() {
  if base64 --decode </dev/null >/dev/null 2>&1; then
    base64 --decode
    return 0
  fi
  if base64 -d </dev/null >/dev/null 2>&1; then
    base64 -d
    return 0
  fi
  base64 -D
}

get_secret_value() {
  local secret="$1"
  local key="$2"
  kubectl -n "$KDC_NAMESPACE" get secret "$secret" -o "jsonpath={.data.${key}}" 2>/dev/null | b64_decode 2>/dev/null || true
}

resolve_prole_kdc_defaults() {
  if [[ -z "$PROLE_KDC_REALM" ]]; then
    PROLE_KDC_REALM="PROLE.LOCAL"
  fi
  if [[ -z "$PROLE_KDC_DOMAIN" ]]; then
    PROLE_KDC_DOMAIN=$(lowercase "$PROLE_KDC_REALM")
  fi
  local mode=""
  if command -v prole_normalize_mode >/dev/null 2>&1; then
    mode=$(prole_normalize_mode "${PROLE_MODE:-}")
  else
    mode="${PROLE_MODE:-}"
  fi
  local k3s_host=""
  if [[ "$mode" == "k3s" ]]; then
    k3s_host=$(registry_host_from_url "${PROLE_K3S_SERVER:-${K3S_SERVER_URL:-}}")
    if [[ -n "$k3s_host" ]] && ([[ -z "${PROLE_KDC_REGISTRY_HOST:-}" ]] || [[ "$PROLE_KDC_REGISTRY_HOST" == "localhost:5000" ]] || [[ "$PROLE_KDC_REGISTRY_HOST" == *"k3d"* ]]); then
      PROLE_KDC_REGISTRY_HOST="${k3s_host}:5000"
    fi
  fi
  if [[ -z "$PROLE_KDC_REGISTRY_INTERNAL" ]]; then
    if [[ -n "${KDC_NAMESPACE:-}" ]]; then
      PROLE_KDC_REGISTRY_INTERNAL="registry.${KDC_NAMESPACE}.svc.cluster.local:5000"
    elif [[ -n "${SERVICE_NAMESPACE:-}" ]]; then
      PROLE_KDC_REGISTRY_INTERNAL="registry.${SERVICE_NAMESPACE}.svc.cluster.local:5000"
    elif [[ -n "${NAMESPACE:-}" ]]; then
      PROLE_KDC_REGISTRY_INTERNAL="registry.${NAMESPACE}.svc.cluster.local:5000"
    fi
  fi
  if [[ "$mode" == "k3s" ]]; then
    if [[ -n "$k3s_host" ]] && ([[ -z "$PROLE_KDC_REGISTRY_INTERNAL" ]] || [[ "$PROLE_KDC_REGISTRY_INTERNAL" == *"k3d"* ]] || [[ "$PROLE_KDC_REGISTRY_INTERNAL" == *".svc.cluster.local"* ]]); then
      PROLE_KDC_REGISTRY_INTERNAL="${k3s_host}:5000"
    fi
  fi
  if [[ -z "$PROLE_KDC_IMAGE" ]]; then
    if [[ -n "$PROLE_KDC_REGISTRY_INTERNAL" ]]; then
      PROLE_KDC_IMAGE="${PROLE_KDC_REGISTRY_INTERNAL}/${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
    else
      PROLE_KDC_IMAGE="${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
    fi
  fi
}

resolve_kdc_docker_dir() {
  if [[ -n "${PROLE_KDC_DOCKER_DIR:-}" && -d "$PROLE_KDC_DOCKER_DIR" ]]; then
    echo "$PROLE_KDC_DOCKER_DIR"
    return 0
  fi
  if [[ -n "${PROLE_HOME:-}" && -d "$PROLE_HOME/prole/authority" ]]; then
    echo "$PROLE_HOME/prole/authority"
    return 0
  fi
  if [[ -d "$SCRIPT_DIR/../prole/authority" ]]; then
    echo "$SCRIPT_DIR/../prole/authority"
    return 0
  fi
  return 1
}

is_truthy() {
  case "${1:-}" in
    1|true|TRUE|True|yes|YES|Yes|on|ON|On) return 0 ;;
  esac
  return 1
}

build_prole_kdc_image() {
  if ! is_truthy "${PROLE_KDC_BUILD_IMAGE:-1}"; then
    return 0
  fi

  local docker_dir
  docker_dir=$(resolve_kdc_docker_dir || true)
  if [[ -z "$docker_dir" ]]; then
    err "ERROR: prole/authority Docker context not found."
    exit 1
  fi

  ensure_docker

  local local_tag="${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
  log "Building authority image: ${local_tag} (context: ${docker_dir}) ..."
  docker build -t "$local_tag" "$docker_dir"

  if [[ -n "$PROLE_KDC_REGISTRY_HOST" ]]; then
    local remote_tag="${PROLE_KDC_REGISTRY_HOST}/${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
    log "Tagging authority image for registry: ${remote_tag}"
    docker tag "$local_tag" "$remote_tag"
    log "Pushing authority image to registry: ${remote_tag}"
    if ! docker push "$remote_tag"; then
      if command -v skopeo >/dev/null 2>&1; then
        log "Docker push failed; retrying with skopeo (insecure registry) ..."
        skopeo copy --dest-tls-verify=false "docker-daemon:${local_tag}" "docker://${remote_tag}"
      else
        err "ERROR: docker push failed and skopeo is not available."
        exit 1
      fi
    fi
  fi

  if [[ -n "$PROLE_KDC_REGISTRY_INTERNAL" ]]; then
    PROLE_KDC_IMAGE="${PROLE_KDC_REGISTRY_INTERNAL}/${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
  elif [[ -n "$PROLE_KDC_REGISTRY_HOST" ]]; then
    PROLE_KDC_IMAGE="${PROLE_KDC_REGISTRY_HOST}/${PROLE_KDC_IMAGE_NAME}:${PROLE_KDC_IMAGE_TAG}"
  else
    PROLE_KDC_IMAGE="${local_tag}"
  fi
}

ensure_prole_kdc_secrets() {
  local secret_name="prole-kdc-secrets"
  if [[ -z "$PROLE_KDC_ADMIN_PASSWORD" ]]; then
    PROLE_KDC_ADMIN_PASSWORD=$(get_secret_value "$secret_name" "admin_password")
  fi
  if [[ -z "$PROLE_KDC_MASTER_PASSWORD" ]]; then
    PROLE_KDC_MASTER_PASSWORD=$(get_secret_value "$secret_name" "master_password")
  fi
  if [[ -z "$PROLE_KDC_TRUST_SHARED_PASSWORD" ]]; then
    PROLE_KDC_TRUST_SHARED_PASSWORD=$(get_secret_value "$secret_name" "trust_shared_password")
  fi
  if [[ -z "$PROLE_KDC_TRUST_PASSWORD" ]]; then
    PROLE_KDC_TRUST_PASSWORD=$(get_secret_value "$secret_name" "trust_password")
  fi

  if [[ -z "$PROLE_KDC_ADMIN_PASSWORD" ]]; then
    PROLE_KDC_ADMIN_PASSWORD=$(gen_password)
  fi
  if [[ -z "$PROLE_KDC_MASTER_PASSWORD" ]]; then
    PROLE_KDC_MASTER_PASSWORD=$(gen_password)
  fi
  if [[ -z "$PROLE_KDC_TRUST_SHARED_PASSWORD" ]]; then
    PROLE_KDC_TRUST_SHARED_PASSWORD="$PROLE_KDC_MASTER_PASSWORD"
  fi

  kubectl -n "$KDC_NAMESPACE" create secret generic "$secret_name" \
    --from-literal=admin_password="$PROLE_KDC_ADMIN_PASSWORD" \
    --from-literal=master_password="$PROLE_KDC_MASTER_PASSWORD" \
    --from-literal=trust_shared_password="$PROLE_KDC_TRUST_SHARED_PASSWORD" \
    --from-literal=trust_password="$PROLE_KDC_TRUST_PASSWORD" \
    --dry-run=client -o yaml | kubectl apply -f - >/dev/null
}

ensure_prole_kdc() {
  if [[ "$PROLE_KDC_ENABLED" == "0" || "$PROLE_KDC_ENABLED" == "false" || "$PROLE_KDC_ENABLED" == "False" ]]; then
    log "Prole KDC disabled (PROLE_KDC_ENABLED=$PROLE_KDC_ENABLED)."
    return 0
  fi

  resolve_prole_kdc_defaults
  build_prole_kdc_image
  ensure_prole_kdc_secrets

  local admin_acl_principal="$PROLE_KDC_ADMIN_PRINCIPAL"
  if [[ "$admin_acl_principal" != *"@"* ]]; then
    admin_acl_principal="${admin_acl_principal}@${PROLE_KDC_REALM}"
  fi

  local trust_block=""
  if [[ -n "$PROLE_KDC_TRUST_REALM" && "$PROLE_KDC_TRUST_REALM" != "$PROLE_KDC_REALM" && -n "$KRB5_KDC" ]]; then
    local trust_admin_server="${KRB5_ADMIN:-$KRB5_KDC}"
    trust_block=$(cat <<EOF

      ${PROLE_KDC_TRUST_REALM} = {
        kdc = ${KRB5_KDC}
        admin_server = ${trust_admin_server}
      }

    [capaths]
      ${PROLE_KDC_REALM} = {
        ${PROLE_KDC_TRUST_REALM} = .
      }
      ${PROLE_KDC_TRUST_REALM} = {
        ${PROLE_KDC_REALM} = .
      }
EOF
)
  fi

  log "Applying Prole KDC '${PROLE_KDC_NAME}' in namespace '${KDC_NAMESPACE}' (realm ${PROLE_KDC_REALM}) ..."
  cat <<EOF | kubectl apply -n "$KDC_NAMESPACE" -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: prole-kdc-config
  namespace: ${KDC_NAMESPACE}
data:
  krb5.conf: |
    [libdefaults]
      default_realm = ${PROLE_KDC_REALM}
      dns_lookup_realm = false
      dns_lookup_kdc = false

    [realms]
      ${PROLE_KDC_REALM} = {
        kdc = 127.0.0.1
        admin_server = 127.0.0.1
      }${trust_block}
  kdc.conf: |
    [kdcdefaults]
      kdc_ports = 88
      kdc_tcp_ports = 88
    [realms]
      ${PROLE_KDC_REALM} = {
        database_name = /var/lib/krb5kdc/principal
        admin_keytab = FILE:/etc/krb5kdc/kadm5.keytab
        acl_file = /etc/krb5kdc/kadm5.acl
        key_stash_file = /etc/krb5kdc/stash
        max_life = 10h 0m 0s
        max_renewable_life = 7d 0h 0m 0s
        default_principal_flags = +preauth
      }
  kadm5.acl: |
    ${admin_acl_principal} *
  entrypoint.sh: |
    #!/usr/bin/env bash
    set -euo pipefail
    export DEBIAN_FRONTEND=noninteractive

    if ! command -v krb5kdc >/dev/null 2>&1; then
      echo "Installing Kerberos packages..."
      echo "krb5-config krb5-config/default_realm string ${PROLE_KDC_REALM}" | debconf-set-selections || true
      echo "krb5-config krb5-config/kerberos_servers string 127.0.0.1" | debconf-set-selections || true
      echo "krb5-config krb5-config/admin_server string 127.0.0.1" | debconf-set-selections || true
      apt-get update
      apt-get install -y --no-install-recommends krb5-kdc krb5-admin-server krb5-user dnsutils ca-certificates
      rm -rf /var/lib/apt/lists/*
    fi

    mkdir -p /etc/krb5kdc /var/lib/krb5kdc
    if [[ -f /opt/prole-kdc/krb5.conf ]]; then
      cp /opt/prole-kdc/krb5.conf /etc/krb5.conf
    fi
    if [[ -f /opt/prole-kdc/kdc.conf ]]; then
      cp /opt/prole-kdc/kdc.conf /etc/krb5kdc/kdc.conf
    fi
    if [[ -f /opt/prole-kdc/kadm5.acl ]]; then
      cp /opt/prole-kdc/kadm5.acl /etc/krb5kdc/kadm5.acl
    fi

    realm="\${PROLE_KDC_REALM}"
    admin_principal="\${PROLE_KDC_ADMIN_PRINCIPAL}"
    if [[ "\${admin_principal}" != *"@"* ]]; then
      admin_principal="\${admin_principal}@\${PROLE_KDC_REALM}"
    fi

    if [[ ! -f /var/lib/krb5kdc/principal ]]; then
      echo "Initializing realm database for \${PROLE_KDC_REALM}..."
      kdb5_util create -s -r "\${realm}" -P "\${PROLE_KDC_MASTER_PASSWORD}"
    fi

    if ! kadmin.local -q "get_principal \${admin_principal}" >/dev/null 2>&1; then
      echo "Creating admin principal \${admin_principal}..."
      kadmin.local -q "addprinc -pw \${PROLE_KDC_ADMIN_PASSWORD} \${admin_principal}"
    fi

    if [[ -n "\${PROLE_KDC_TRUST_REALM:-}" && "\${PROLE_KDC_TRUST_REALM}" != "\${PROLE_KDC_REALM}" ]]; then
      shared_pw="\${PROLE_KDC_TRUST_SHARED_PASSWORD:-\${PROLE_KDC_MASTER_PASSWORD}}"
      if ! kadmin.local -q "get_principal krbtgt/\${PROLE_KDC_TRUST_REALM}@\${PROLE_KDC_REALM}" >/dev/null 2>&1; then
        echo "Creating trust principal krbtgt/\${PROLE_KDC_TRUST_REALM}@\${PROLE_KDC_REALM}..."
        kadmin.local -q "addprinc -pw \${shared_pw} krbtgt/\${PROLE_KDC_TRUST_REALM}@\${PROLE_KDC_REALM}"
      fi

      if [[ -n "\${PROLE_KDC_TRUST_ADMIN:-}" && -n "\${PROLE_KDC_TRUST_PASSWORD:-}" ]]; then
        echo "Creating reciprocal trust principal in \${PROLE_KDC_TRUST_REALM}..."
        kadmin -r "\${PROLE_KDC_TRUST_REALM}" -p "\${PROLE_KDC_TRUST_ADMIN}" -w "\${PROLE_KDC_TRUST_PASSWORD}" \
          -q "addprinc -pw \${shared_pw} krbtgt/\${PROLE_KDC_REALM}@\${PROLE_KDC_TRUST_REALM}" || true
      else
        echo "WARN: Missing PROLE_KDC_TRUST_ADMIN/PROLE_KDC_TRUST_PASSWORD; skipping external trust principal."
      fi
    fi

    krb5kdc
    exec kadmind -nofork
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ${PROLE_KDC_NAME}
  namespace: ${KDC_NAMESPACE}
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ${PROLE_KDC_NAME}
  template:
    metadata:
      labels:
        app: ${PROLE_KDC_NAME}
    spec:
      containers:
        - name: kdc
          image: ${PROLE_KDC_IMAGE}
          command: ["/bin/bash", "/opt/prole-kdc/entrypoint.sh"]
          env:
            - name: PROLE_KDC_REALM
              value: "${PROLE_KDC_REALM}"
            - name: PROLE_KDC_ADMIN_PRINCIPAL
              value: "${PROLE_KDC_ADMIN_PRINCIPAL}"
            - name: PROLE_KDC_MASTER_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: prole-kdc-secrets
                  key: master_password
            - name: PROLE_KDC_ADMIN_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: prole-kdc-secrets
                  key: admin_password
            - name: PROLE_KDC_TRUST_SHARED_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: prole-kdc-secrets
                  key: trust_shared_password
            - name: PROLE_KDC_TRUST_REALM
              value: "${PROLE_KDC_TRUST_REALM}"
            - name: PROLE_KDC_TRUST_ADMIN
              value: "${PROLE_KDC_TRUST_ADMIN}"
            - name: PROLE_KDC_TRUST_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: prole-kdc-secrets
                  key: trust_password
          ports:
            - name: krb5-udp
              containerPort: 88
              protocol: UDP
            - name: krb5-tcp
              containerPort: 88
              protocol: TCP
            - name: kpasswd-udp
              containerPort: 464
              protocol: UDP
            - name: kpasswd-tcp
              containerPort: 464
              protocol: TCP
            - name: kadmin
              containerPort: 749
              protocol: TCP
          volumeMounts:
            - name: prole-kdc-config
              mountPath: /opt/prole-kdc
            - name: prole-kdc-data
              mountPath: /var/lib/krb5kdc
            - name: prole-kdc-data
              mountPath: /etc/krb5kdc
      volumes:
        - name: prole-kdc-config
          configMap:
            name: prole-kdc-config
        - name: prole-kdc-data
          emptyDir: {}
---
apiVersion: v1
kind: Service
metadata:
  name: ${PROLE_KDC_SERVICE}
  namespace: ${KDC_NAMESPACE}
spec:
  selector:
    app: ${PROLE_KDC_NAME}
  ports:
    - name: krb5-udp
      port: 88
      targetPort: 88
      protocol: UDP
    - name: krb5-tcp
      port: 88
      targetPort: 88
      protocol: TCP
    - name: kpasswd-udp
      port: 464
      targetPort: 464
      protocol: UDP
    - name: kpasswd-tcp
      port: 464
      targetPort: 464
      protocol: TCP
    - name: kadmin
      port: 749
      targetPort: 749
      protocol: TCP
EOF

  kubectl -n "$KDC_NAMESPACE" rollout status deploy/${PROLE_KDC_NAME} --timeout=120s || true
}

cleanup_prole_kdc() {
  log "Removing Prole KDC resources (if present)..."
  kubectl -n "$KDC_NAMESPACE" delete service "$PROLE_KDC_SERVICE" --ignore-not-found
  kubectl -n "$KDC_NAMESPACE" delete deployment "$PROLE_KDC_NAME" --ignore-not-found
  kubectl -n "$KDC_NAMESPACE" delete configmap prole-kdc-config --ignore-not-found
}

status() {
  log "--- init_kdc status ---"
  log "Namespace: $KDC_NAMESPACE"
  log "Prole KDC enabled: ${PROLE_KDC_ENABLED:-0}"
  log "Prole KDC realm: ${PROLE_KDC_REALM:-<unset>}"
  log "Prole KDC service: ${PROLE_KDC_SERVICE:-<unset>}"
  log "Prole KDC image: ${PROLE_KDC_IMAGE:-<unset>}"
  if kubectl -n "$KDC_NAMESPACE" get deploy "$PROLE_KDC_NAME" >/dev/null 2>&1; then
    log "[OK] Prole KDC deployment present"
  else
    log "[INFO] Prole KDC deployment not present"
  fi
}

case "$ACTION" in
  initialize|init|update|deploy|start)
    ensure_tools
    ensure_namespace
    ensure_prole_kdc
    ;;
  status)
    ensure_tools
    status
    ;;
  cleanup|delete|remove)
    ensure_tools
    ensure_namespace
    cleanup_prole_kdc
    ;;
  *)
    err "Usage: $0 {initialize|update|status|cleanup}"
    exit 2
    ;;
esac