Merge pull request #324 from naturallaw777/copilot/fix-rdp-boot-time-setup

fix(rdp): prepend /run/wrappers/bin to PATH and add pkexec preflight check

app/tests/test_rdp_module_boot_setup.py

@@ -0,0 +1,122 @@
+import unittest
+from pathlib import Path
+
+
+RDP_NIX = Path(__file__).resolve().parents[2] / "modules" / "rdp.nix"
+USERNAME_READ = "USERNAME=\"$(tr -d '\\n' < \"$USERNAME_FILE\")\""
+USERNAME_LENGTH_GUARD = "if [ \"''${#USERNAME}\" -gt 32 ]; then"
+SHORT_PASSWORD_GUARD = 'if [ "\'\'${#PASSWORD}" -lt 8 ]; then'
+
+
+def _section(source: str, start: str, end: str) -> str:
+    start_idx = source.find(start)
+    if start_idx == -1:
+        raise AssertionError(f"Expected section start not found: {start!r}")
+    end_idx = source.find(end, start_idx)
+    if end_idx == -1:
+        raise AssertionError(f"Expected section end not found: {end!r}")
+    return source[start_idx:end_idx]
+
+
+class RdpModuleBootSetupTests(unittest.TestCase):
+    def setUp(self):
+        self.source = RDP_NIX.read_text()
+        self.gnome_service = _section(
+            self.source,
+            "systemd.services.gnome-remote-desktop = {",
+            "systemd.tmpfiles.rules = [",
+        )
+        self.setup_service = _section(
+            self.source,
+            "systemd.services.gnome-remote-desktop-setup = {",
+            "};\n}",
+        )
+
+    def test_does_not_redeclare_gnome_remote_desktop_user(self):
+        self.assertNotIn("users.users.gnome-remote-desktop", self.source)
+        self.assertNotIn("createHome = true;", self.source)
+
+    def test_main_service_requires_setup_before_starting(self):
+        self.assertIn('wantedBy = [ "graphical.target" ];', self.gnome_service)
+        self.assertIn('after = [ "gnome-remote-desktop-setup.service" ];', self.gnome_service)
+        self.assertIn('requires = [ "gnome-remote-desktop-setup.service" ];', self.gnome_service)
+
+    def test_setup_waits_for_configuration_service_and_bounded_timeout(self):
+        self.assertIn('wantedBy = [ "graphical.target" ];', self.setup_service)
+        self.assertIn('before = [ "gnome-remote-desktop.service" ];', self.setup_service)
+        self.assertIn('"dbus.service"', self.setup_service)
+        self.assertIn('"gnome-remote-desktop-configuration.service"', self.setup_service)
+        self.assertNotIn("RemainAfterExit", self.setup_service)
+        self.assertIn('TimeoutStartSec = "2min";', self.setup_service)
+        self.assertIn('timeout --kill-after=5s 10s', self.setup_service)
+        self.assertIn('echo "grdctl command timed out: $*" >&2', self.setup_service)
+        self.assertIn('echo "grdctl command failed (exit $rc): $*" >&2', self.setup_service)
+
+    def test_setup_runs_grdctl_directly_as_root(self):
+        # The oneshot service runs as root; grdctl --system is called directly.
+        # GRD 50.x invokes pkexec internally, but the call itself is plain
+        # grdctl --system, not a manual pkexec invocation.
+        self.assertIn('grdctl --system "$@"', self.setup_service)
+        self.assertNotIn("runuser", self.setup_service)
+        self.assertNotIn("sudo", self.setup_service)
+        # No direct Nix-store pkexec invocation (pkgs.polkit}/bin/pkexec).
+        self.assertNotIn("pkgs.polkit}/bin/pkexec", self.setup_service)
+
+    def test_privilege_escalation_packages_absent_from_setup_path(self):
+        self.assertNotIn("pkgs.polkit", self.setup_service)
+        self.assertNotIn("pkgs.util-linux", self.setup_service)
+
+    def test_run_wrappers_bin_prepended_to_path(self):
+        # /run/wrappers/bin must be prepended to PATH before any grdctl_system
+        # invocation so that grdctl --system resolves the NixOS setuid pkexec.
+        path_export = 'export PATH="/run/wrappers/bin:$PATH"'
+        grdctl_marker = "grdctl_system"
+        script = self.setup_service
+        path_idx = script.find(path_export)
+        grdctl_idx = script.find(grdctl_marker)
+        self.assertGreater(path_idx, -1, f"{path_export!r} not found in setup script")
+        self.assertGreater(
+            grdctl_idx, path_idx,
+            "PATH export must appear before the first grdctl_system usage",
+        )
+
+    def test_pkexec_preflight_check(self):
+        # A preflight must confirm /run/wrappers/bin/pkexec is executable
+        # with a clear error message before any GRD configuration changes.
+        self.assertIn("test -x /run/wrappers/bin/pkexec", self.setup_service)
+        self.assertIn(
+            "/run/wrappers/bin/pkexec is absent or not executable",
+            self.setup_service,
+        )
+
+    def test_hub_files_are_the_source_of_truth_for_username_and_password(self):
+        self.assertIn('DEFAULT_USERNAME="sovran"', self.setup_service)
+        self.assertIn('if [ ! -f "$USERNAME_FILE" ]; then', self.setup_service)
+        self.assertIn(USERNAME_READ, self.setup_service)
+        self.assertIn(USERNAME_LENGTH_GUARD, self.setup_service)
+        self.assertIn('case "$USERNAME" in', self.setup_service)
+        self.assertIn('[A-Za-z_][A-Za-z0-9_-]*)', self.setup_service)
+        self.assertIn("RDP username is too long (''${#USERNAME} characters, maximum 32)", self.setup_service)
+        self.assertIn("RDP username must start with a letter or underscore and contain only letters, numbers, underscores, and hyphens", self.setup_service)
+        self.assertIn('if [ ! -f "$PASSWORD_FILE" ]; then', self.setup_service)
+        self.assertIn("tr -d '\\n'", self.setup_service)
+        self.assertIn('"$PASSWORD_FILE"', self.setup_service)
+        self.assertIn(SHORT_PASSWORD_GUARD, self.setup_service)
+        self.assertIn("RDP password is too short (''${#PASSWORD} characters, minimum 8)", self.setup_service)
+        self.assertIn('grdctl_system rdp set-credentials "$USERNAME" "$PASSWORD"', self.setup_service)
+        self.assertNotIn('grdctl --system rdp set-credentials sovran "$PASSWORD"', self.setup_service)
+
+    def test_secure_permissions_are_enforced_for_state_and_secret_files(self):
+        self.assertIn('"d /var/lib/gnome-remote-desktop/tls 0700', self.source)
+        self.assertIn("chmod 700", self.setup_service)
+        self.assertIn('chmod 600 "$USERNAME_FILE"', self.setup_service)
+        self.assertIn('chmod 600 "$PASSWORD_FILE"', self.setup_service)
+        self.assertIn('chmod 600 "$CRED_FILE"', self.setup_service)
+        self.assertIn('chmod 600 "$TLS_DIR/rdp-tls.key"', self.setup_service)
+        self.assertIn('chmod 644 "$TLS_DIR/rdp-tls.crt"', self.setup_service)
+        self.assertIn('LOCAL_IP="$(hostname -I | awk \'{print $1}\')"', self.setup_service)
+        self.assertIn('LOCAL_IP="127.0.0.1"', self.setup_service)
+
+
+if __name__ == "__main__":
+    unittest.main()

modules/rdp.nix

@@ -2,70 +2,104 @@
 
 lib.mkIf config.sovran_systemsOS.features.rdp {
 
-  users.users.gnome-remote-desktop = {
-    isSystemUser = true;
-    group = "gnome-remote-desktop";
-    home = "/var/lib/gnome-remote-desktop";
-    createHome = true;
-  };
-  users.groups.gnome-remote-desktop = {};
-
   # Enable the GNOME Remote Desktop service at the system level
   services.gnome.gnome-remote-desktop.enable = true;
 
   # Open RDP port in the firewall
   networking.firewall.allowedTCPPorts = [ 3389 ];
 
-  # Ensure the service actually starts and waits for setup to complete
+  # Ensure the service only starts after setup succeeds
   systemd.services.gnome-remote-desktop = {
     wantedBy = [ "graphical.target" ];
     after = [ "gnome-remote-desktop-setup.service" ];
-    wants = [ "gnome-remote-desktop-setup.service" ];
+    requires = [ "gnome-remote-desktop-setup.service" ];
   };
 
   systemd.tmpfiles.rules = [
-    "d /var/lib/gnome-remote-desktop 0750 gnome-remote-desktop gnome-remote-desktop -"
-    "d /var/lib/gnome-remote-desktop/.local 0750 gnome-remote-desktop gnome-remote-desktop -"
-    "d /var/lib/gnome-remote-desktop/.local/share 0750 gnome-remote-desktop gnome-remote-desktop -"
-    "d /var/lib/gnome-remote-desktop/.local/share/gnome-remote-desktop 0750 gnome-remote-desktop gnome-remote-desktop -"
+    "d /var/lib/gnome-remote-desktop/.local 0700 gnome-remote-desktop gnome-remote-desktop -"
+    "d /var/lib/gnome-remote-desktop/.local/share 0700 gnome-remote-desktop gnome-remote-desktop -"
+    "d /var/lib/gnome-remote-desktop/.local/share/gnome-remote-desktop 0700 gnome-remote-desktop gnome-remote-desktop -"
+    "d /var/lib/gnome-remote-desktop/tls 0700 gnome-remote-desktop gnome-remote-desktop -"
   ];
 
   systemd.services.gnome-remote-desktop-setup = {
     description = "Configure GNOME Remote Desktop RDP";
-    wantedBy = [ "multi-user.target" ];
+    wantedBy = [ "graphical.target" ];
     before = [ "gnome-remote-desktop.service" ];
-    after = [ "systemd-tmpfiles-setup.service" "network-online.target" ];
-    wants = [ "network-online.target" ];
+    after = [
+      "dbus.service"
+      "systemd-tmpfiles-setup.service"
+      "network-online.target"
+      "gnome-remote-desktop-configuration.service"
+    ];
+    wants = [
+      "network-online.target"
+      "gnome-remote-desktop-configuration.service"
+    ];
     serviceConfig = {
       Type = "oneshot";
-      RemainAfterExit = true;
+      TimeoutStartSec = "2min";
     };
     path = [
-      pkgs.gnome-remote-desktop
-      pkgs.polkit
-      pkgs.openssl
-      pkgs.hostname
+      pkgs.coreutils
       pkgs.gawk
+      pkgs.gnome-remote-desktop
+      pkgs.hostname
+      pkgs.openssl
+      pkgs.systemd
     ];
     script = ''
-      # Ensure directory structure exists
-      mkdir -p /var/lib/gnome-remote-desktop/.local/share/gnome-remote-desktop
-      chown -R gnome-remote-desktop:gnome-remote-desktop /var/lib/gnome-remote-desktop
+      set -euo pipefail
 
-      TLS_DIR="/var/lib/gnome-remote-desktop/tls"
-      CRED_FILE="/var/lib/gnome-remote-desktop/rdp-credentials"
+      # GRD 50.x invokes pkexec internally for every grdctl --system call, even
+      # when the caller is root.  NixOS exposes the required setuid wrapper at
+      # /run/wrappers/bin/pkexec; the Nix-store polkit binary is not setuid and
+      # must not shadow it.  Prepend the wrapper directory so every subsequent
+      # grdctl --system resolves the correct binary.
+      export PATH="/run/wrappers/bin:$PATH"
+
+      STATE_DIR="/var/lib/gnome-remote-desktop"
+      TLS_DIR="$STATE_DIR/tls"
+      USERNAME_FILE="$STATE_DIR/rdp-username"
+      PASSWORD_FILE="$STATE_DIR/rdp-password"
+      CRED_FILE="$STATE_DIR/rdp-credentials"
+      DEFAULT_USERNAME="sovran"
+
+      grdctl_system() {
+        local rc=0
+
+        if timeout --kill-after=5s 10s \
+          grdctl --system "$@"; then
+          return 0
+        else
+          rc=$?
+        fi
+
+        if [ "$rc" -eq 124 ] || [ "$rc" -eq 137 ]; then
+          echo "grdctl command timed out: $*" >&2
+        fi
+        echo "grdctl command failed (exit $rc): $*" >&2
+
+        return "$rc"
+      }
+
+      mkdir -p "$STATE_DIR/.local/share/gnome-remote-desktop" "$TLS_DIR"
+      chown -R gnome-remote-desktop:gnome-remote-desktop "$STATE_DIR"
+      chmod 700 \
+        "$STATE_DIR" \
+        "$STATE_DIR/.local" \
+        "$STATE_DIR/.local/share" \
+        "$STATE_DIR/.local/share/gnome-remote-desktop" \
+        "$TLS_DIR"
 
-      # Regenerate TLS certificate if missing OR if ownership is wrong
-      # (disable/re-enable cycle can break ownership or grdctl state)
       NEED_REGEN=0
       if [ ! -f "$TLS_DIR/rdp-tls.crt" ] || [ ! -f "$TLS_DIR/rdp-tls.key" ]; then
         NEED_REGEN=1
-      elif [ "$(stat -c '%U' "$TLS_DIR/rdp-tls.key" 2>/dev/null)" != "gnome-remote-desktop" ]; then
+      elif [ "$(stat -c '%U:%G' "$TLS_DIR/rdp-tls.key" 2>/dev/null)" != "gnome-remote-desktop:gnome-remote-desktop" ]; then
         NEED_REGEN=1
       fi
 
       if [ "$NEED_REGEN" = "1" ]; then
-        mkdir -p "$TLS_DIR"
         rm -f "$TLS_DIR/rdp-tls.key" "$TLS_DIR/rdp-tls.crt"
         openssl req -x509 -newkey ec -pkeyopt ec_paramgen_curve:prime256v1 \
           -sha256 -nodes -days 3650 \
@@ -75,39 +109,59 @@ lib.mkIf config.sovran_systemsOS.features.rdp {
         echo "Generated new RDP TLS certificate"
       fi
 
-      # Always fix ownership and permissions (handles re-enable after disable)
-      chown -R gnome-remote-desktop:gnome-remote-desktop "$TLS_DIR"
+      chown gnome-remote-desktop:gnome-remote-desktop "$TLS_DIR/rdp-tls.key" "$TLS_DIR/rdp-tls.crt"
       chmod 600 "$TLS_DIR/rdp-tls.key"
       chmod 644 "$TLS_DIR/rdp-tls.crt"
 
-      # Configure TLS certificate
-      grdctl --system rdp set-tls-cert "$TLS_DIR/rdp-tls.crt"
-      grdctl --system rdp set-tls-key "$TLS_DIR/rdp-tls.key"
+      if [ ! -f "$USERNAME_FILE" ]; then
+        printf '%s\n' "$DEFAULT_USERNAME" > "$USERNAME_FILE"
+      fi
+      USERNAME="$(tr -d '\n' < "$USERNAME_FILE")"
+      if [ -z "$USERNAME" ]; then
+        USERNAME="$DEFAULT_USERNAME"
+        printf '%s\n' "$USERNAME" > "$USERNAME_FILE"
+      fi
+      if [ "''${#USERNAME}" -gt 32 ]; then
+        echo "RDP username is too long (''${#USERNAME} characters, maximum 32): $USERNAME from $USERNAME_FILE" >&2
+        exit 1
+      fi
+      case "$USERNAME" in
+        [A-Za-z_][A-Za-z0-9_-]*)
+          ;;
+        *)
+          echo "RDP username must start with a letter or underscore and contain only letters, numbers, underscores, and hyphens: $USERNAME from $USERNAME_FILE" >&2
+          exit 1
+          ;;
+      esac
+      chown gnome-remote-desktop:gnome-remote-desktop "$USERNAME_FILE"
+      chmod 600 "$USERNAME_FILE"
 
-      # Generate password on first boot only
-      PASSWORD=""
-      if [ ! -f /var/lib/gnome-remote-desktop/rdp-password ]; then
-        PASSWORD=$(openssl rand -base64 16)
-        echo "$PASSWORD" > /var/lib/gnome-remote-desktop/rdp-password
-        chmod 600 /var/lib/gnome-remote-desktop/rdp-password
-      else
-        PASSWORD=$(cat /var/lib/gnome-remote-desktop/rdp-password)
+      if [ ! -f "$PASSWORD_FILE" ]; then
+        openssl rand -base64 16 > "$PASSWORD_FILE"
+      fi
+      PASSWORD="$(tr -d '\n' < "$PASSWORD_FILE")"
+      if [ -z "$PASSWORD" ]; then
+        echo "RDP password file is empty: $PASSWORD_FILE" >&2
+        exit 1
+      fi
+      if [ "''${#PASSWORD}" -lt 8 ]; then
+        echo "RDP password is too short (''${#PASSWORD} characters, minimum 8): $PASSWORD_FILE" >&2
+        exit 1
+      fi
+      chown gnome-remote-desktop:gnome-remote-desktop "$PASSWORD_FILE"
+      chmod 600 "$PASSWORD_FILE"
+
+      LOCAL_IP="$(hostname -I | awk '{print $1}')"
+      if [ -z "$LOCAL_IP" ]; then
+        LOCAL_IP="127.0.0.1"
       fi
 
-      # Write username to a separate file for the hub
-      echo "sovran" > /var/lib/gnome-remote-desktop/rdp-username
-      chmod 600 /var/lib/gnome-remote-desktop/rdp-username
-
-      # Get current IP address
-      LOCAL_IP=$(hostname -I | awk '{print $1}')
-
-      # Always rewrite the credentials file with the current IP
       cat > "$CRED_FILE" <<EOF
       ========================================
        GNOME Remote Desktop (RDP) Credentials
       ========================================
 
-       Username: sovran
+       Username: $USERNAME
        Password: $PASSWORD
 
        Connect from any RDP client to:
@@ -116,11 +170,22 @@ lib.mkIf config.sovran_systemsOS.features.rdp {
       ========================================
       EOF
 
+      chown gnome-remote-desktop:gnome-remote-desktop "$CRED_FILE"
       chmod 600 "$CRED_FILE"
 
-      # Enable RDP backend and set credentials
-      grdctl --system rdp enable
-      grdctl --system rdp set-credentials sovran "$PASSWORD"
+      # Preflight: the NixOS setuid pkexec wrapper must be present and executable
+      # before any grdctl --system call.  Absence means the system was booted
+      # without security.wrappers or the wrapper directory is not mounted yet.
+      if ! test -x /run/wrappers/bin/pkexec; then
+        echo "Preflight check failed: /run/wrappers/bin/pkexec is absent or not executable." >&2
+        echo "GNOME Remote Desktop system configuration requires the NixOS setuid pkexec wrapper at /run/wrappers/bin/pkexec." >&2
+        exit 1
+      fi
+
+      grdctl_system rdp enable
+      grdctl_system rdp set-tls-cert "$TLS_DIR/rdp-tls.crt"
+      grdctl_system rdp set-tls-key "$TLS_DIR/rdp-tls.key"
+      grdctl_system rdp set-credentials "$USERNAME" "$PASSWORD"
 
       echo "GNOME Remote Desktop RDP configured successfully"
     '';