[glib: 4/5] Add a test for GDBusServer authentication

[Philip Withnall <pwithnall src gnome org>]

commit 9f962ebeac1d67223579ad0d261c4c8215f7c427
Author: Simon McVittie <smcv collabora com>
Date:   Fri Oct 11 19:02:55 2019 +0100

    Add a test for GDBusServer authentication
    
    In particular, if libbdus is available, we test interoperability with
    a libdbus client: see GNOME/glib#1831. Because that issue describes a
    race condition, we do each test repeatedly to try to hit the failing
    case.
    
    Signed-off-by: Simon McVittie <smcv collabora com>

 gio/tests/gdbus-server-auth.c | 491 ++++++++++++++++++++++++++++++++++++++++++
 gio/tests/meson.build         |  10 +-
 2 files changed, 500 insertions(+), 1 deletion(-)
---
diff --git a/gio/tests/gdbus-server-auth.c b/gio/tests/gdbus-server-auth.c
new file mode 100644
index 000000000..6a72ba6c1
--- /dev/null
+++ b/gio/tests/gdbus-server-auth.c
@@ -0,0 +1,491 @@
+/*
+ * Copyright 2019 Collabora Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gio/gio.h>
+
+#ifdef HAVE_DBUS1
+#include <dbus/dbus.h>
+#endif
+
+typedef enum
+{
+  INTEROP_FLAGS_EXTERNAL = (1 << 0),
+  INTEROP_FLAGS_ANONYMOUS = (1 << 1),
+  INTEROP_FLAGS_SHA1 = (1 << 2),
+  INTEROP_FLAGS_TCP = (1 << 3),
+  INTEROP_FLAGS_LIBDBUS = (1 << 4),
+  INTEROP_FLAGS_NONE = 0
+} InteropFlags;
+
+static gboolean
+allow_external_cb (G_GNUC_UNUSED GDBusAuthObserver *observer,
+                   const char *mechanism,
+                   G_GNUC_UNUSED gpointer user_data)
+{
+  if (g_strcmp0 (mechanism, "EXTERNAL") == 0)
+    {
+      g_debug ("Accepting EXTERNAL authentication");
+      return TRUE;
+    }
+  else
+    {
+      g_debug ("Rejecting \"%s\" authentication: not EXTERNAL", mechanism);
+      return FALSE;
+    }
+}
+
+static gboolean
+allow_anonymous_cb (G_GNUC_UNUSED GDBusAuthObserver *observer,
+                    const char *mechanism,
+                    G_GNUC_UNUSED gpointer user_data)
+{
+  if (g_strcmp0 (mechanism, "ANONYMOUS") == 0)
+    {
+      g_debug ("Accepting ANONYMOUS authentication");
+      return TRUE;
+    }
+  else
+    {
+      g_debug ("Rejecting \"%s\" authentication: not ANONYMOUS", mechanism);
+      return FALSE;
+    }
+}
+
+static gboolean
+allow_sha1_cb (G_GNUC_UNUSED GDBusAuthObserver *observer,
+               const char *mechanism,
+               G_GNUC_UNUSED gpointer user_data)
+{
+  if (g_strcmp0 (mechanism, "DBUS_COOKIE_SHA1") == 0)
+    {
+      g_debug ("Accepting DBUS_COOKIE_SHA1 authentication");
+      return TRUE;
+    }
+  else
+    {
+      g_debug ("Rejecting \"%s\" authentication: not DBUS_COOKIE_SHA1",
+               mechanism);
+      return FALSE;
+    }
+}
+
+static gboolean
+allow_any_mechanism_cb (G_GNUC_UNUSED GDBusAuthObserver *observer,
+                        const char *mechanism,
+                        G_GNUC_UNUSED gpointer user_data)
+{
+  g_debug ("Accepting \"%s\" authentication", mechanism);
+  return TRUE;
+}
+
+static gboolean
+authorize_any_authenticated_peer_cb (G_GNUC_UNUSED GDBusAuthObserver *observer,
+                                     G_GNUC_UNUSED GIOStream *stream,
+                                     GCredentials *credentials,
+                                     G_GNUC_UNUSED gpointer user_data)
+{
+  if (credentials == NULL)
+    {
+      g_debug ("Authorizing peer with no credentials");
+    }
+  else
+    {
+      gchar *str = g_credentials_to_string (credentials);
+
+      g_debug ("Authorizing peer with credentials: %s", str);
+      g_free (str);
+    }
+
+  return TRUE;
+}
+
+static GDBusMessage *
+whoami_filter_cb (GDBusConnection *connection,
+                  GDBusMessage *message,
+                  gboolean incoming,
+                  G_GNUC_UNUSED gpointer user_data)
+{
+  if (!incoming)
+    return message;
+
+  if (g_dbus_message_get_message_type (message) == G_DBUS_MESSAGE_TYPE_METHOD_CALL &&
+      g_strcmp0 (g_dbus_message_get_member (message), "WhoAmI") == 0)
+    {
+      GDBusMessage *reply = g_dbus_message_new_method_reply (message);
+      gint64 uid = -1;
+      gint64 pid = -1;
+#ifdef G_OS_UNIX
+      GCredentials *credentials = g_dbus_connection_get_peer_credentials (connection);
+
+      if (credentials != NULL)
+        {
+          uid = (gint64) g_credentials_get_unix_user (credentials, NULL);
+          pid = (gint64) g_credentials_get_unix_pid (credentials, NULL);
+        }
+#endif
+
+      g_dbus_message_set_body (reply,
+                               g_variant_new ("(xx)", uid, pid));
+      g_dbus_connection_send_message (connection, reply,
+                                      G_DBUS_SEND_MESSAGE_FLAGS_NONE,
+                                      NULL, NULL);
+
+      /* handled */
+      g_object_unref (message);
+      return NULL;
+    }
+
+  return message;
+}
+
+static gboolean
+new_connection_cb (G_GNUC_UNUSED GDBusServer *server,
+                   GDBusConnection *connection,
+                   G_GNUC_UNUSED gpointer user_data)
+{
+  GCredentials *credentials = g_dbus_connection_get_peer_credentials (connection);
+
+  if (credentials == NULL)
+    {
+      g_debug ("New connection from peer with no credentials");
+    }
+  else
+    {
+      gchar *str = g_credentials_to_string (credentials);
+
+      g_debug ("New connection from peer with credentials: %s", str);
+      g_free (str);
+    }
+
+  g_object_ref (connection);
+  g_dbus_connection_add_filter (connection, whoami_filter_cb, NULL, NULL);
+  return TRUE;
+}
+
+#ifdef HAVE_DBUS1
+typedef struct
+{
+  DBusError error;
+  DBusConnection *conn;
+  DBusMessage *call;
+  DBusMessage *reply;
+} LibdbusCall;
+
+static void
+libdbus_call_task_cb (GTask *task,
+                      G_GNUC_UNUSED gpointer source_object,
+                      gpointer task_data,
+                      G_GNUC_UNUSED GCancellable *cancellable)
+{
+  LibdbusCall *libdbus_call = task_data;
+
+  libdbus_call->reply = dbus_connection_send_with_reply_and_block (libdbus_call->conn,
+                                                                   libdbus_call->call,
+                                                                   -1,
+                                                                   &libdbus_call->error);
+}
+#endif /* HAVE_DBUS1 */
+
+static void
+store_result_cb (G_GNUC_UNUSED GObject *source_object,
+                 GAsyncResult *res,
+                 gpointer user_data)
+{
+  GAsyncResult **result = user_data;
+
+  g_assert_nonnull (result);
+  g_assert_null (*result);
+  *result = g_object_ref (res);
+}
+
+static void
+assert_expected_uid_pid (InteropFlags flags,
+                         gint64 uid,
+                         gint64 pid)
+{
+#ifdef G_OS_UNIX
+  if (flags & (INTEROP_FLAGS_ANONYMOUS | INTEROP_FLAGS_SHA1 | INTEROP_FLAGS_TCP))
+    {
+      /* No assertion. There is no guarantee whether credentials will be
+       * passed even though we didn't send them. Conversely, if
+       * credentials were not passed,
+       * g_dbus_connection_get_peer_credentials() always returns the
+       * credentials of the socket, and not the uid that a
+       * client might have proved it has by using DBUS_COOKIE_SHA1. */
+    }
+  else    /* We should prefer EXTERNAL whenever it is allowed. */
+    {
+#ifdef __linux__
+      /* We know that both GDBus and libdbus support full credentials-passing
+       * on Linux. */
+      g_assert_cmpint (uid, ==, getuid ());
+      g_assert_cmpint (pid, ==, getpid ());
+#else
+      g_test_message ("Please open a merge request to add appropriate "
+                      "assertions for your platform");
+#endif
+    }
+#endif /* G_OS_UNIX */
+}
+
+static void
+do_test_server_auth (const char *listenable_address,
+                     InteropFlags flags)
+{
+  GError *error = NULL;
+  GDBusServer *server;
+  GDBusAuthObserver *observer;
+  GDBusServerFlags server_flags = G_DBUS_SERVER_FLAGS_RUN_IN_THREAD;
+  gchar *guid;
+  const char *connectable_address;
+  GDBusConnection *client;
+  GAsyncResult *result = NULL;
+  GVariant *tuple;
+  gint64 uid, pid;
+#ifdef HAVE_DBUS1
+  /* GNOME/glib#1831 seems to involve a race condition, so try a few times
+   * to see if we can trigger it. */
+  gsize i;
+  gsize n = 20;
+#endif
+
+  if (g_str_has_prefix (listenable_address, "tcp:") ||
+      g_str_has_prefix (listenable_address, "nonce-tcp:"))
+    g_assert_cmpint (flags & INTEROP_FLAGS_TCP, !=, 0);
+  else
+    g_assert_cmpint (flags & INTEROP_FLAGS_TCP, ==, 0);
+
+  g_test_message ("Testing GDBus server at %s / libdbus client, with flags: "
+                  "external:%s "
+                  "anonymous:%s "
+                  "sha1:%s "
+                  "tcp:%s",
+                  listenable_address,
+                  (flags & INTEROP_FLAGS_EXTERNAL) ? "true" : "false",
+                  (flags & INTEROP_FLAGS_ANONYMOUS) ? "true" : "false",
+                  (flags & INTEROP_FLAGS_SHA1) ? "true" : "false",
+                  (flags & INTEROP_FLAGS_TCP) ? "true" : "false");
+
+#ifndef G_OS_UNIX
+  if (g_str_has_prefix (listenable_address, "unix:"))
+    {
+      g_test_skip ("unix: addresses only work on Unix");
+      return;
+    }
+#endif
+
+#if !defined(G_CREDENTIALS_UNIX_CREDENTIALS_MESSAGE_SUPPORTED) \
+  && !defined(G_CREDENTIALS_SOCKET_GET_CREDENTIALS_SUPPORTED)
+  if (flags & INTEROP_FLAGS_EXTERNAL)
+    {
+      g_test_skip ("EXTERNAL authentication not implemented on this platform");
+      return;
+    }
+#endif
+
+  if (flags & INTEROP_FLAGS_ANONYMOUS)
+    server_flags |= G_DBUS_SERVER_FLAGS_AUTHENTICATION_ALLOW_ANONYMOUS;
+
+  observer = g_dbus_auth_observer_new ();
+
+  if (flags & INTEROP_FLAGS_EXTERNAL)
+    g_signal_connect (observer, "allow-mechanism",
+                      G_CALLBACK (allow_external_cb), NULL);
+  else if (flags & INTEROP_FLAGS_ANONYMOUS)
+    g_signal_connect (observer, "allow-mechanism",
+                      G_CALLBACK (allow_anonymous_cb), NULL);
+  else if (flags & INTEROP_FLAGS_SHA1)
+    g_signal_connect (observer, "allow-mechanism",
+                      G_CALLBACK (allow_sha1_cb), NULL);
+  else
+    g_signal_connect (observer, "allow-mechanism",
+                      G_CALLBACK (allow_any_mechanism_cb), NULL);
+
+  g_signal_connect (observer, "authorize-authenticated-peer",
+                    G_CALLBACK (authorize_any_authenticated_peer_cb),
+                    NULL);
+
+  guid = g_dbus_generate_guid ();
+  server = g_dbus_server_new_sync (listenable_address,
+                                   server_flags,
+                                   guid,
+                                   observer,
+                                   NULL,
+                                   &error);
+  g_assert_no_error (error);
+  g_assert_nonnull (server);
+  g_signal_connect (server, "new-connection", G_CALLBACK (new_connection_cb), NULL);
+  g_dbus_server_start (server);
+  connectable_address = g_dbus_server_get_client_address (server);
+
+  result = NULL;
+  g_dbus_connection_new_for_address (connectable_address,
+                                     G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT,
+                                     NULL, NULL, store_result_cb, &result);
+
+  while (result == NULL)
+    g_main_context_iteration (NULL, TRUE);
+
+  client = g_dbus_connection_new_for_address_finish (result, &error);
+  g_assert_no_error (error);
+  g_assert_nonnull (client);
+  g_clear_object (&result);
+
+  g_dbus_connection_call (client, NULL, "/", "com.example.Test", "WhoAmI",
+                          NULL, G_VARIANT_TYPE ("(xx)"),
+                          G_DBUS_CALL_FLAGS_NONE, -1, NULL, store_result_cb,
+                          &result);
+
+  while (result == NULL)
+    g_main_context_iteration (NULL, TRUE);
+
+  tuple = g_dbus_connection_call_finish (client, result, &error);
+  g_assert_no_error (error);
+  g_assert_nonnull (tuple);
+  g_clear_object (&result);
+  g_clear_object (&client);
+
+  uid = -2;
+  pid = -2;
+  g_variant_get (tuple, "(xx)", &uid, &pid);
+
+  g_debug ("Server says GDBus client is uid %" G_GINT64_FORMAT ", pid %" G_GINT64_FORMAT,
+           uid, pid);
+
+  assert_expected_uid_pid (flags, uid, pid);
+
+  g_clear_pointer (&tuple, g_variant_unref);
+
+#ifdef HAVE_DBUS1
+  for (i = 0; i < n; i++)
+    {
+      LibdbusCall libdbus_call = { DBUS_ERROR_INIT, NULL, NULL, NULL };
+      GTask *task;
+
+      libdbus_call.conn = dbus_connection_open_private (connectable_address,
+                                                        &libdbus_call.error);
+      g_assert_cmpstr (libdbus_call.error.name, ==, NULL);
+      g_assert_nonnull (libdbus_call.conn);
+
+      libdbus_call.call = dbus_message_new_method_call (NULL, "/",
+                                                        "com.example.Test",
+                                                        "WhoAmI");
+
+      if (libdbus_call.call == NULL)
+        g_error ("Out of memory");
+
+      result = NULL;
+      task = g_task_new (NULL, NULL, store_result_cb, &result);
+      g_task_set_task_data (task, &libdbus_call, NULL);
+      g_task_run_in_thread (task, libdbus_call_task_cb);
+
+      while (result == NULL)
+        g_main_context_iteration (NULL, TRUE);
+
+      g_clear_object (&result);
+
+      g_assert_cmpstr (libdbus_call.error.name, ==, NULL);
+      g_assert_nonnull (libdbus_call.reply);
+
+      uid = -2;
+      pid = -2;
+      dbus_message_get_args (libdbus_call.reply, &libdbus_call.error,
+                             DBUS_TYPE_INT64, &uid,
+                             DBUS_TYPE_INT64, &pid,
+                             DBUS_TYPE_INVALID);
+      g_assert_cmpstr (libdbus_call.error.name, ==, NULL);
+
+      g_debug ("Server says libdbus client %" G_GSIZE_FORMAT " is uid %" G_GINT64_FORMAT ", pid %" 
G_GINT64_FORMAT,
+               i, uid, pid);
+      assert_expected_uid_pid (flags | INTEROP_FLAGS_LIBDBUS, uid, pid);
+
+      dbus_connection_close (libdbus_call.conn);
+      dbus_connection_unref (libdbus_call.conn);
+      dbus_message_unref (libdbus_call.call);
+      dbus_message_unref (libdbus_call.reply);
+      g_clear_object (&task);
+    }
+#else /* !HAVE_DBUS1 */
+  g_test_skip ("Testing interop with libdbus not supported");
+#endif /* !HAVE_DBUS1 */
+
+  g_dbus_server_stop (server);
+  g_clear_object (&server);
+  g_clear_object (&observer);
+  g_free (guid);
+}
+
+static void
+test_server_auth (void)
+{
+  do_test_server_auth ("unix:tmpdir=/tmp/gdbus-test", INTEROP_FLAGS_NONE);
+}
+
+static void
+test_server_auth_tcp (void)
+{
+  do_test_server_auth ("tcp:host=127.0.0.1", INTEROP_FLAGS_TCP);
+}
+
+static void
+test_server_auth_anonymous (void)
+{
+  do_test_server_auth ("unix:tmpdir=/tmp/gdbus-test", INTEROP_FLAGS_ANONYMOUS);
+}
+
+static void
+test_server_auth_anonymous_tcp (void)
+{
+  do_test_server_auth ("tcp:host=127.0.0.1", INTEROP_FLAGS_ANONYMOUS | INTEROP_FLAGS_TCP);
+}
+
+static void
+test_server_auth_external (void)
+{
+  do_test_server_auth ("unix:tmpdir=/tmp/gdbus-test", INTEROP_FLAGS_EXTERNAL);
+}
+
+static void
+test_server_auth_sha1 (void)
+{
+  do_test_server_auth ("unix:tmpdir=/tmp/gdbus-test", INTEROP_FLAGS_SHA1);
+}
+
+static void
+test_server_auth_sha1_tcp (void)
+{
+  do_test_server_auth ("tcp:host=127.0.0.1", INTEROP_FLAGS_SHA1 | INTEROP_FLAGS_TCP);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/gdbus/server-auth", test_server_auth);
+  g_test_add_func ("/gdbus/server-auth/tcp", test_server_auth_tcp);
+  g_test_add_func ("/gdbus/server-auth/anonymous", test_server_auth_anonymous);
+  g_test_add_func ("/gdbus/server-auth/anonymous/tcp", test_server_auth_anonymous_tcp);
+  g_test_add_func ("/gdbus/server-auth/external", test_server_auth_external);
+  g_test_add_func ("/gdbus/server-auth/sha1", test_server_auth_sha1);
+  g_test_add_func ("/gdbus/server-auth/sha1/tcp", test_server_auth_sha1_tcp);
+
+  return g_test_run();
+}
diff --git a/gio/tests/meson.build b/gio/tests/meson.build
index b5593a4ec..8ad02f5c0 100644
--- a/gio/tests/meson.build
+++ b/gio/tests/meson.build
@@ -115,7 +115,15 @@ if dbus1_dep.found()
     'gdbus-serialization' : {
       'extra_sources' : ['gdbus-tests.c'],
       'dependencies' : [dbus1_dep],
-    }
+    },
+    'gdbus-server-auth' : {
+      'dependencies' : [dbus1_dep],
+    },
+  }
+else
+  # We can build a cut-down version of this test without libdbus
+  gio_tests += {
+    'gdbus-server-auth' : {},
   }
 endif