fix: make Linux installation permissions deterministic

deploy/install-from-git.sh

@@ -5,7 +5,7 @@ umask 077
 
 ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
 INSTALLER="$ROOT/deploy/install.sh"
-INSTALLER_SHA256=${KAIDI_INSTALLER_SHA256:-8a75ee99a1c2f426c11ea18c8ef65f4f4ac3f8d52321c358f3ff645baa6ad99c}
+INSTALLER_SHA256=${KAIDI_INSTALLER_SHA256:-bc9001197af843dc323907a98023064ccc4f184e000543d2086b8a6f8161dbc7}
 RELEASE_API_URL=${KAIDI_RELEASE_API_URL:-https://git.awaioi.com/api/v1/repos/ERP-Team/kaidi/releases/latest}
 PUBLIC_KEY_SHA256=${KAIDI_RELEASE_PUBLIC_KEY_SHA256:-807c6aec1dc3f7ce494db16aa9d763c66f292033c38f328afd0390d2715a8cd9}
 TOKEN_FILE=${KAIDI_RELEASE_TOKEN_FILE:-}

deploy/install.sh

@@ -28,6 +28,9 @@ BACKUP_DIR=
 JAVA_STAGED_DIR=
 JAVA_PREVIOUS_DIR=
 JAVA_ACTIVATED=false
+SERVICE_USER=kaidi
+SERVICE_GROUP=kaidi
+HOST_ARCH=
 
 log() { printf '[kaidi-install] %s\n' "$*"; }
 die() { printf '[kaidi-install] ERROR: %s\n' "$*" >&2; exit 1; }
@@ -36,14 +39,42 @@ sha256_file() {
   sha256sum "$1" | awk '{print $1}'
 }
 
+normalized_host_arch() {
+  local machine host_bits
+  machine=$(uname -m)
+  host_bits=$(getconf LONG_BIT 2>/dev/null || true)
+  case "$machine" in
+    x86_64|amd64)
+      [ "$host_bits" = 32 ] && printf x86 || printf x86_64
+      ;;
+    i386|i486|i586|i686) printf x86 ;;
+    aarch64|arm64)
+      [ "$host_bits" = 32 ] && printf arm || printf aarch64
+      ;;
+    armv7l|armv6l) printf arm ;;
+    *) die "Unsupported CPU architecture: $machine" ;;
+  esac
+}
+
 preflight_host() {
+  local host_bits expected_bits
   [ "$(uname -s)" = Linux ] || die "The installer only supports Linux"
   [ "$APP_ROOT" = /opt/kaidi ] && [ "$STATE_ROOT" = /var/lib/kaidi ] \
     && [ "$UPDATE_STATE_ROOT" = /var/lib/kaidi-update ] && [ "$CONFIG_ROOT" = /etc/kaidi ] \
     || die "Custom installation roots are not supported by the packaged systemd configuration"
   command -v systemctl >/dev/null 2>&1 || die "systemd is required"
+  command -v systemd-analyze >/dev/null 2>&1 || die "systemd-analyze is required"
+  command -v getconf >/dev/null 2>&1 || die "getconf is required"
   [ -d /run/systemd/system ] || die "systemd is not running as PID 1"
   [ -d /etc/systemd/system ] || die "/etc/systemd/system is missing"
+  HOST_ARCH=$(normalized_host_arch)
+  host_bits=$(getconf LONG_BIT 2>/dev/null || true)
+  case "$HOST_ARCH" in
+    x86_64|aarch64) expected_bits=64 ;;
+    x86|arm) expected_bits=32 ;;
+  esac
+  [ "$host_bits" = "$expected_bits" ] \
+    || die "CPU architecture and userspace word size do not match: $HOST_ARCH/$host_bits-bit"
   [[ "$TRUSTED_PUBLIC_KEY_SHA256" =~ ^[0-9A-Fa-f]{64}$ ]] \
     || die "Set KAIDI_RELEASE_PUBLIC_KEY_SHA256 to the trusted release public-key SHA-256"
   case "$REINSTALL" in
@@ -62,28 +93,31 @@ preflight_host() {
     [ ! -e "$STATE_ROOT/setup/locked" ] \
       || die "The setup wizard is already locked; use a normal repair reinstall"
   fi
+  log "Environment verified: $(uname -sr), architecture=$HOST_ARCH, userspace=${host_bits}-bit, systemd"
 }
 
-[ "$(id -u)" -eq 0 ] || die "Run with sudo or as root"
-[ -z "$RELEASE_TOKEN" ] || [ -z "$RELEASE_TOKEN_FILE" ] \
-  || die "Set only one of KAIDI_RELEASE_TOKEN or KAIDI_RELEASE_TOKEN_FILE"
-if [ -n "$RELEASE_TOKEN_FILE" ]; then
-  [ -f "$RELEASE_TOKEN_FILE" ] && [ ! -L "$RELEASE_TOKEN_FILE" ] \
-    || die "KAIDI_RELEASE_TOKEN_FILE must be a regular file"
-  [ "$(wc -c < "$RELEASE_TOKEN_FILE" | tr -d '[:space:]')" -le 512 ] \
-    || die "KAIDI_RELEASE_TOKEN_FILE is too large"
-  RELEASE_TOKEN=$(cat "$RELEASE_TOKEN_FILE")
-fi
-[ "$REINSTALL" = "true" ] || [ ! -e "$APP_ROOT/current" ] \
-  || die "Kaidi Finance is already installed; use the system update page"
-if [ -z "$RELEASE_API_URL" ]; then
-  case "$RELEASE_BASE_URL" in
-    *OWNER/REPO*) die "Set KAIDI_RELEASE_BASE_URL or KAIDI_RELEASE_API_URL to the Git release source" ;;
-  esac
-fi
-[ -z "$RELEASE_TOKEN" ] || { [ "${#RELEASE_TOKEN}" -le 512 ] \
-  && ! printf '%s' "$RELEASE_TOKEN" | grep -q '[[:cntrl:]]'; } \
-  || die "KAIDI_RELEASE_TOKEN is invalid"
+validate_inputs() {
+  [ "$(id -u)" -eq 0 ] || die "Run with sudo or as root"
+  [ -z "$RELEASE_TOKEN" ] || [ -z "$RELEASE_TOKEN_FILE" ] \
+    || die "Set only one of KAIDI_RELEASE_TOKEN or KAIDI_RELEASE_TOKEN_FILE"
+  if [ -n "$RELEASE_TOKEN_FILE" ]; then
+    [ -f "$RELEASE_TOKEN_FILE" ] && [ ! -L "$RELEASE_TOKEN_FILE" ] \
+      || die "KAIDI_RELEASE_TOKEN_FILE must be a regular file"
+    [ "$(wc -c < "$RELEASE_TOKEN_FILE" | tr -d '[:space:]')" -le 512 ] \
+      || die "KAIDI_RELEASE_TOKEN_FILE is too large"
+    RELEASE_TOKEN=$(cat "$RELEASE_TOKEN_FILE")
+  fi
+  [ "$REINSTALL" = "true" ] || [ ! -e "$APP_ROOT/current" ] \
+    || die "Kaidi Finance is already installed; use the system update page"
+  if [ -z "$RELEASE_API_URL" ]; then
+    case "$RELEASE_BASE_URL" in
+      *OWNER/REPO*) die "Set KAIDI_RELEASE_BASE_URL or KAIDI_RELEASE_API_URL to the Git release source" ;;
+    esac
+  fi
+  [ -z "$RELEASE_TOKEN" ] || { [ "${#RELEASE_TOKEN}" -le 512 ] \
+    && ! printf '%s' "$RELEASE_TOKEN" | grep -q '[[:cntrl:]]'; } \
+    || die "KAIDI_RELEASE_TOKEN is invalid"
+}
 
 download() {
   local url=$1 output=$2
@@ -170,12 +204,26 @@ install_packages() {
 }
 
 azul_arch() {
-  case "$(uname -m)" in
-    x86_64|amd64) printf x86 ;;
-    i386|i486|i586|i686) printf i686 ;;
-    aarch64|arm64) printf arm_64 ;;
-    armv7l|armv6l) printf arm ;;
-    *) die "Unsupported CPU architecture: $(uname -m)" ;;
+  case "${HOST_ARCH:-$(normalized_host_arch)}" in
+    x86_64) printf x86 ;;
+    x86) printf i686 ;;
+    aarch64) printf arm_64 ;;
+    arm) printf arm ;;
+  esac
+}
+
+java_arch_matches_host() {
+  local java_bin=$1 java_arch host_arch
+  host_arch=${HOST_ARCH:-$(normalized_host_arch)}
+  java_arch=$(
+    "$java_bin" -XshowSettings:properties -version 2>&1 \
+      | sed -n 's/^[[:space:]]*os\.arch = [[:space:]]*//p' \
+      | head -n 1
+  )
+  case "$host_arch:$java_arch" in
+    x86_64:amd64|x86_64:x86_64|x86:x86|x86:i386|x86:i486|x86:i586|x86:i686|\
+    aarch64:aarch64|aarch64:arm64|arm:arm) return 0 ;;
+    *) return 1 ;;
   esac
 }
 
@@ -194,6 +242,7 @@ system_java_home() {
       | head -n 1
   )
   [[ "$java_major" =~ ^[0-9]+$ ]] && [ "$java_major" -ge 17 ] || return 1
+  java_arch_matches_host "$java_bin" || return 1
   resolved_java=$(readlink -f "$java_bin" 2>/dev/null || printf '%s' "$java_bin")
   case "$resolved_java" in
     */bin/java) home=${resolved_java%/bin/java} ;;
@@ -204,12 +253,14 @@ system_java_home() {
 }
 
 prepare_java() {
-  local api java_metadata package_metadata package_uuid java_url java_sha256 actual_sha256 system_home
+  local api java_metadata package_metadata package_uuid java_url java_sha256 actual_sha256 system_home java_line
   if system_home=$(system_java_home); then
     JAVA_STAGED_DIR="$WORK_DIR/java.next"
-    ln -s "$system_home" "$JAVA_STAGED_DIR"
-    log "Using existing Java 17 runtime at $system_home"
-    "$JAVA_STAGED_DIR/bin/java" -version
+    mkdir -p "$JAVA_STAGED_DIR"
+    log "Copying existing Java 17 runtime from $system_home into the managed application directory"
+    COPYFILE_DISABLE=1 cp -R "$system_home/." "$JAVA_STAGED_DIR/"
+    java_line=$("$JAVA_STAGED_DIR/bin/java" -version 2>&1 | head -n 1)
+    log "Local Java verified: $java_line"
     return 0
   fi
   log "No local Java 17 runtime found; downloading the official Azul Java 17 runtime"
@@ -231,18 +282,88 @@ prepare_java() {
   [ "$actual_sha256" = "$java_sha256" ] || die "Java 17 runtime SHA-256 verification failed"
   mkdir -p "$JAVA_STAGED_DIR"
   tar -xzf "$WORK_DIR/java.tar.gz" --strip-components=1 -C "$JAVA_STAGED_DIR"
-  "$JAVA_STAGED_DIR/bin/java" -version
+  java_arch_matches_host "$JAVA_STAGED_DIR/bin/java" \
+    || die "Downloaded Java runtime architecture does not match $HOST_ARCH"
+  java_line=$("$JAVA_STAGED_DIR/bin/java" -version 2>&1 | head -n 1)
+  log "Downloaded Java verified: $java_line"
 }
 
 activate_java() {
   mkdir -p "$APP_ROOT/runtime"
   JAVA_PREVIOUS_DIR="$WORK_DIR/java.previous"
-  if [ -e "$APP_ROOT/runtime/java" ]; then
+  if [ -e "$APP_ROOT/runtime/java" ] || [ -L "$APP_ROOT/runtime/java" ]; then
     mv "$APP_ROOT/runtime/java" "$JAVA_PREVIOUS_DIR"
   fi
   mv "$JAVA_STAGED_DIR" "$APP_ROOT/runtime/java"
+  chown -R root:"$SERVICE_GROUP" "$APP_ROOT/runtime/java"
+  chmod -R u=rwX,g=rX,o= "$APP_ROOT/runtime/java"
   JAVA_ACTIVATED=true
-  "$APP_ROOT/runtime/java/bin/java" -version
+}
+
+ensure_service_identity() {
+  local existing_home nologin_path
+  command -v getent >/dev/null 2>&1 || die "getent is required"
+  if ! getent group "$SERVICE_GROUP" >/dev/null 2>&1; then
+    groupadd --system "$SERVICE_GROUP"
+  fi
+  if id "$SERVICE_USER" >/dev/null 2>&1; then
+    existing_home=$(getent passwd "$SERVICE_USER" | awk -F: '{print $6}')
+    [ "$existing_home" = "$STATE_ROOT" ] \
+      || die "Existing user $SERVICE_USER has unexpected home directory $existing_home"
+    if ! id -nG "$SERVICE_USER" | tr ' ' '\n' | grep -Fxq "$SERVICE_GROUP"; then
+      usermod --append --groups "$SERVICE_GROUP" "$SERVICE_USER"
+    fi
+    return 0
+  fi
+  nologin_path=$(command -v nologin 2>/dev/null || true)
+  [ -n "$nologin_path" ] || nologin_path=/usr/sbin/nologin
+  [ -x "$nologin_path" ] || die "A nologin shell is required"
+  useradd --system --gid "$SERVICE_GROUP" --home-dir "$STATE_ROOT" --shell "$nologin_path" "$SERVICE_USER"
+}
+
+prepare_managed_layout() {
+  command -v runuser >/dev/null 2>&1 || die "runuser is required"
+  install -d -o root -g "$SERVICE_GROUP" -m 0750 \
+    "$APP_ROOT" "$APP_ROOT/releases" "$APP_ROOT/runtime" "$APP_ROOT/bin"
+  install -d -o "$SERVICE_USER" -g "$SERVICE_GROUP" -m 0750 \
+    "$STATE_ROOT" "$STATE_ROOT/files" "$STATE_ROOT/tmp" /var/log/kaidi
+  install -d -o "$SERVICE_USER" -g "$SERVICE_GROUP" -m 0700 "$STATE_ROOT/setup"
+  install -d -o root -g "$SERVICE_GROUP" -m 0750 "$UPDATE_STATE_ROOT"
+  install -d -o "$SERVICE_USER" -g "$SERVICE_GROUP" -m 0750 "$UPDATE_STATE_ROOT/inbox"
+  install -d -o root -g root -m 0700 "$CONFIG_ROOT"
+}
+
+secure_release_tree() {
+  local release_dir=$1
+  chown -R root:"$SERVICE_GROUP" "$release_dir"
+  find "$release_dir" -type d -exec chmod 0750 {} +
+  find "$release_dir" -type f -exec chmod 0640 {} +
+  chmod 0750 "$release_dir/ops/update.sh"
+}
+
+restore_security_contexts() {
+  command -v restorecon >/dev/null 2>&1 || return 0
+  restorecon -RF "$APP_ROOT" "$STATE_ROOT" "$UPDATE_STATE_ROOT" /var/log/kaidi \
+    /etc/systemd/system/kaidi-finance.service \
+    /etc/systemd/system/kaidi-update.service \
+    /etc/systemd/system/kaidi-update.path >/dev/null 2>&1 \
+    || log "SELinux context restoration reported a warning; service access checks will decide whether installation can continue"
+}
+
+verify_service_access() {
+  # shellcheck disable=SC2016 # Positional parameters are expanded by the child shell.
+  runuser -u "$SERVICE_USER" -- sh -c \
+    'cd "$1" && test -r app.jar && test -r public/index.html' sh "$APP_ROOT/current" \
+    || die "$SERVICE_USER cannot traverse or read the active release"
+  runuser -u "$SERVICE_USER" -- test -x "$APP_ROOT/runtime/java/bin/java" \
+    || die "$SERVICE_USER cannot execute the managed Java runtime"
+  runuser -u "$SERVICE_USER" -- "$APP_ROOT/runtime/java/bin/java" -version >/dev/null 2>&1 \
+    || die "The managed Java runtime cannot execute as $SERVICE_USER"
+  runuser -u "$SERVICE_USER" -- test -w "$STATE_ROOT/files" \
+    || die "$SERVICE_USER cannot write the file-storage directory"
+  runuser -u "$SERVICE_USER" -- test -w "$UPDATE_STATE_ROOT/inbox" \
+    || die "$SERVICE_USER cannot write the update inbox"
+  log "Service-user filesystem and Java access checks passed"
 }
 
 random_secret() { openssl rand -base64 36 | tr -d '\n/+=' | cut -c1-36; }
@@ -599,6 +720,12 @@ backup_managed_state() {
 
 restore_unit_state() {
   local unit=$1 was_enabled=$2 was_active=$3
+  if ! systemctl cat "$unit" >/dev/null 2>&1; then
+    systemctl reset-failed "$unit" >/dev/null 2>&1 || true
+    [ "$was_enabled" = false ] && [ "$was_active" = false ]
+    return
+  fi
+  systemctl reset-failed "$unit" >/dev/null 2>&1 || true
   if [ "$was_enabled" = true ]; then
     systemctl enable "$unit" >/dev/null 2>&1
   else
@@ -631,7 +758,7 @@ rollback_install() {
   local index=0 path rollback_failed=false
   set +e
   log "Installation failed; restoring the previous managed state"
-  systemctl stop kaidi-update.path kaidi-finance.service >/dev/null 2>&1 || rollback_failed=true
+  systemctl stop kaidi-update.path kaidi-finance.service >/dev/null 2>&1 || true
   for path in "${MANAGED_PATHS[@]}"; do
     restore_managed_path "$path" "$index" || rollback_failed=true
     index=$((index + 1))
@@ -639,7 +766,7 @@ rollback_install() {
   if [ -n "$RELEASE_DIR" ]; then
     rm -rf -- "$RELEASE_DIR" || rollback_failed=true
   fi
-  if [ -d "$JAVA_PREVIOUS_DIR" ]; then
+  if [ -d "$JAVA_PREVIOUS_DIR" ] || [ -L "$JAVA_PREVIOUS_DIR" ]; then
     rm -rf -- "$APP_ROOT/runtime/java" || rollback_failed=true
     mkdir -p "$APP_ROOT/runtime" || rollback_failed=true
     mv "$JAVA_PREVIOUS_DIR" "$APP_ROOT/runtime/java" || rollback_failed=true
@@ -666,8 +793,10 @@ cleanup() {
   exit "$result"
 }
 
+main() {
 trap cleanup EXIT
 
+validate_inputs
 configure_app_port
 preflight_host
 install_packages
@@ -714,25 +843,18 @@ find "$WORK_DIR/extracted" -type l -print -quit | grep -q . \
 [ "$(cat "$WORK_DIR/extracted/VERSION")" = "$VERSION" ] || die "Release version mismatch"
 [ -x "$WORK_DIR/extracted/ops/update.sh" ] || die "Release updater is missing"
 
-prepare_java
 configure_database
 preflight_database
-
-id kaidi >/dev/null 2>&1 || useradd --system --home "$STATE_ROOT" --shell /usr/sbin/nologin kaidi
-mkdir -p "$APP_ROOT/releases" "$APP_ROOT/bin" "$STATE_ROOT/files" "$STATE_ROOT/tmp" \
-  "$STATE_ROOT/setup" "$UPDATE_STATE_ROOT/inbox" "$CONFIG_ROOT" /var/log/kaidi
-chown -R kaidi:kaidi "$STATE_ROOT" "$UPDATE_STATE_ROOT/inbox" /var/log/kaidi
-chown root:kaidi "$UPDATE_STATE_ROOT"
-chmod 0750 "$STATE_ROOT" "$STATE_ROOT/files" "$STATE_ROOT/tmp" "$UPDATE_STATE_ROOT" "$UPDATE_STATE_ROOT/inbox"
-chmod 0700 "$STATE_ROOT/setup"
+ensure_service_identity
+prepare_managed_layout
+prepare_java
 
 RELEASE_DIR="$APP_ROOT/releases/$VERSION"
 [ ! -e "$RELEASE_DIR" ] || RELEASE_DIR="$APP_ROOT/releases/${VERSION}-reinstall-$(date -u +%Y%m%dT%H%M%SZ)"
 backup_managed_state
 activate_java
 mv "$WORK_DIR/extracted" "$RELEASE_DIR"
-chown -R root:root "$RELEASE_DIR"
-chmod -R go-w "$RELEASE_DIR"
+secure_release_tree "$RELEASE_DIR"
 ln -sfn "$RELEASE_DIR" "$APP_ROOT/current.next"
 mv -Tf "$APP_ROOT/current.next" "$APP_ROOT/current"
 install -m 0755 "$RELEASE_DIR/ops/update.sh" "$APP_ROOT/bin/update.sh"
@@ -824,7 +946,15 @@ chmod 0600 "$CONFIG_ROOT/update.env"
 install -m 0644 "$RELEASE_DIR/ops/kaidi-finance.service" /etc/systemd/system/kaidi-finance.service
 install -m 0644 "$RELEASE_DIR/ops/kaidi-update.service" /etc/systemd/system/kaidi-update.service
 install -m 0644 "$RELEASE_DIR/ops/kaidi-update.path" /etc/systemd/system/kaidi-update.path
+restore_security_contexts
+verify_service_access
+systemd-analyze verify \
+  /etc/systemd/system/kaidi-finance.service \
+  /etc/systemd/system/kaidi-update.service \
+  /etc/systemd/system/kaidi-update.path >/dev/null \
+  || die "Installed systemd units failed validation"
 systemctl daemon-reload
+systemctl reset-failed kaidi-finance.service >/dev/null 2>&1 || true
 systemctl enable kaidi-finance.service
 systemctl restart kaidi-finance.service
 wait_for_health
@@ -875,3 +1005,6 @@ if [ "$REINSTALL" != true ] && [ "$SETUP_WIZARD" != true ]; then
   log "Temporary credentials: /root/kaidi-first-login.txt"
   log "Change the temporary password immediately after first sign-in"
 fi
+}
+
+main "$@"

deploy/systemd/kaidi-finance.service

@@ -2,6 +2,8 @@
 Description=Kaidi Finance System
 After=network-online.target
 Wants=network-online.target
+StartLimitIntervalSec=60
+StartLimitBurst=3
 
 [Service]
 Type=simple

deploy/update.sh

@@ -18,6 +18,8 @@ RELEASE_API_URL=${UPDATE_RELEASE_API_URL:-}
 RELEASE_TOKEN=${UPDATE_RELEASE_TOKEN:-}
 CACHE_ROOT=${KAIDI_UPDATE_CACHE_ROOT:-$STATE_ROOT/cache}
 SERVICE_NAME=${KAIDI_SERVICE_NAME:-kaidi-finance.service}
+SERVICE_USER=${KAIDI_SERVICE_USER:-kaidi}
+SERVICE_GROUP=${KAIDI_SERVICE_GROUP:-kaidi}
 HEALTH_URL=${KAIDI_HEALTH_URL:-http://127.0.0.1:18080/actuator/health}
 APP_INDEX_URL=${KAIDI_APP_INDEX_URL:-http://127.0.0.1:18080/}
 LOCK_FILE=$STATE_ROOT/update.lock
@@ -38,9 +40,10 @@ case "$HEALTH_ATTEMPTS:$HEALTH_INTERVAL_SECONDS" in
 esac
 [ "$HEALTH_ATTEMPTS" -ge 1 ] || { printf '%s\n' "Update health-check attempts must be at least 1" >&2; exit 1; }
 
-mkdir -p "$STATE_ROOT/inbox" "$PROCESSING_DIR" "$FAILED_REQUEST_ROOT" "$TRANSACTION_ROOT" \
-  "$STATE_ROOT/work" "$APP_ROOT/releases" "$LOG_ROOT" "$BACKUP_ROOT" "$CACHE_ROOT"
-chmod 0700 "$PROCESSING_DIR" "$FAILED_REQUEST_ROOT" "$TRANSACTION_ROOT" "$BACKUP_ROOT" "$CACHE_ROOT"
+bootstrap_die() {
+  printf '%s\n' "$1" >&2
+  exit 1
+}
 
 status() {
   state=$1
@@ -77,6 +80,43 @@ fail() {
   exit 1
 }
 
+prepare_update_layout() {
+  id "$SERVICE_USER" >/dev/null 2>&1 || bootstrap_die "Service user $SERVICE_USER is missing"
+  id -nG "$SERVICE_USER" | tr ' ' '\n' | grep -Fxq "$SERVICE_GROUP" \
+    || bootstrap_die "Service user $SERVICE_USER is not a member of group $SERVICE_GROUP"
+  command -v runuser >/dev/null 2>&1 || bootstrap_die "runuser is required"
+  install -d -o root -g "$SERVICE_GROUP" -m 0750 \
+    "$APP_ROOT" "$APP_ROOT/releases" "$APP_ROOT/runtime" "$APP_ROOT/bin" "$STATE_ROOT" \
+    || bootstrap_die "Managed application or update directories could not be prepared"
+  install -d -o "$SERVICE_USER" -g "$SERVICE_GROUP" -m 0750 "$STATE_ROOT/inbox" "$LOG_ROOT" \
+    || bootstrap_die "Writable update directories could not be prepared"
+  install -d -o root -g root -m 0700 \
+    "$PROCESSING_DIR" "$FAILED_REQUEST_ROOT" "$TRANSACTION_ROOT" "$STATE_ROOT/work" \
+    "$BACKUP_ROOT" "$CACHE_ROOT" \
+    || bootstrap_die "Private update directories could not be prepared"
+}
+
+secure_release_tree() {
+  release_dir=$1
+  chown -R root:"$SERVICE_GROUP" "$release_dir" || return 1
+  find "$release_dir" -type d -exec chmod 0750 {} + || return 1
+  find "$release_dir" -type f -exec chmod 0640 {} + || return 1
+  chmod 0750 "$release_dir/ops/update.sh"
+}
+
+verify_release_access() {
+  release_dir=$1
+  # shellcheck disable=SC2016 # Positional parameters are expanded by the child shell.
+  runuser -u "$SERVICE_USER" -- sh -c \
+    'cd "$1" && test -r app.jar && test -r public/index.html' sh "$release_dir" \
+    || return 1
+  runuser -u "$SERVICE_USER" -- test -x "$APP_ROOT/runtime/java/bin/java" \
+    || return 1
+  runuser -u "$SERVICE_USER" -- "$APP_ROOT/runtime/java/bin/java" -version >/dev/null 2>&1
+}
+
+prepare_update_layout
+
 # shellcheck disable=SC2329 # Invoked by the EXIT trap below.
 cleanup() {
   rc=$?
@@ -329,6 +369,7 @@ rollback_active_transaction() {
     rollback_ok=false
   fi
   restore_operations || rollback_ok=false
+  systemctl reset-failed "$SERVICE_NAME" >/dev/null 2>&1 || true
   systemctl start "$SERVICE_NAME" || rollback_ok=false
   if [ "$rollback_ok" = true ] && verify_app_surface; then
     remove_failed_release "$failed_release"
@@ -520,8 +561,14 @@ if [ -e "$RELEASE_DIR" ]; then
   rm -rf "$RELEASE_DIR" || fail "Failed release staging directory could not be cleaned"
 fi
 mv "$WORK_DIR/extracted" "$RELEASE_DIR" || fail "Release directory could not be activated"
-chown -R root:root "$RELEASE_DIR" || fail "Release ownership could not be secured"
-chmod -R go-w "$RELEASE_DIR" || fail "Release permissions could not be secured"
+secure_release_tree "$RELEASE_DIR" || fail "Release ownership or permissions could not be secured"
+if command -v restorecon >/dev/null 2>&1; then
+  restorecon -RF "$APP_ROOT" >/dev/null 2>&1 || true
+fi
+if ! verify_release_access "$RELEASE_DIR"; then
+  rm -rf "$RELEASE_DIR"
+  fail "Service user cannot access the release or managed Java runtime"
+fi
 
 PREVIOUS_TARGET=$(readlink "$APP_ROOT/current" 2>/dev/null || true)
 mkdir "$ACTIVE_TRANSACTION"
@@ -552,6 +599,7 @@ write_transaction_value phase APP_SWITCHED
 
 status RUNNING "Starting and verifying release $TARGET_VERSION" "$TARGET_VERSION"
 write_transaction_value phase HEALTH_CHECKING
+systemctl reset-failed "$SERVICE_NAME" >/dev/null 2>&1 || true
 if systemctl start "$SERVICE_NAME" \
   && systemctl is-active --quiet kaidi-update.path \
   && verify_app_surface; then