libeos-parental-controls: Add support for flatpak refs

As well as handling paths on the file system, we should allow flatpak
refs to be explicitly handled in the app filter.

Both refs and paths can be stored safely in the same app filter GStrv
because paths are always absolute and refs always start with ‘app/’ or
‘runtime/’.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://phabricator.endlessm.com/T24020

eos-parental-controls-client/eos-parental-controls-client.py

@@ -171,20 +171,28 @@ def command_get(user, quiet=False, interactive=True):
 
 
 def command_check(user, path, quiet=False, interactive=True):
-    """Check the given path is runnable by the given user, according to their
+    """Check the given path or flatpak ref is runnable by the given user,
-    app filter."""
+    according to their app filter."""
     user_id = __lookup_user_id_or_error(user)
     app_filter = __get_app_filter_or_error(user_id, interactive)
 
+    if path.startswith('app/') or path.startswith('runtime/'):
+        # Flatpak ref
+        is_allowed = app_filter.is_flatpak_ref_allowed(path)
+        noun = 'Flatpak ref'
+    else:
+        # File system path
         path = os.path.abspath(path)
+        is_allowed = app_filter.is_path_allowed(path)
+        noun = 'Path'
 
-    if app_filter.is_path_allowed(path):
+    if is_allowed:
-        print('Path {} is allowed by app filter for user {}'.format(
+        print('{} {} is allowed by app filter for user {}'.format(
-            path, user_id))
+            noun, path, user_id))
         return
     else:
-        print('Path {} is not allowed by app filter for user {}'.format(
+        print('{} {} is not allowed by app filter for user {}'.format(
-            path, user_id))
+            noun, path, user_id))
         raise SystemExit(EXIT_PATH_NOT_ALLOWED)
 
 
@@ -214,6 +222,8 @@ def command_set(user, app_filter_args=None, quiet=False, interactive=True):
                       file=sys.stderr)
                 raise SystemExit(EXIT_INVALID_OPTION)
             builder.set_oars_value(section, value)
+        elif arg.startswith('app/') or arg.startswith('runtime/'):
+            builder.blacklist_flatpak_ref(arg)
         else:
             builder.blacklist_path(arg)
     app_filter = builder.end()

libeos-parental-controls/app-filter.c

@@ -162,6 +162,40 @@ epc_app_filter_is_path_allowed (EpcAppFilter *filter,
     }
 }
 
+/**
+ * epc_app_filter_is_flatpak_ref_allowed:
+ * @filter: an #EpcAppFilter
+ * @app_ref: flatpak ref for the app
+ *
+ * Check whether the flatpak app with the given @app_ref is allowed to be run
+ * according to this app filter.
+ *
+ * Returns: %TRUE if the user this @filter corresponds to is allowed to run the
+ *    flatpak called @app_ref according to the @filter policy; %FALSE otherwise
+ * Since: 0.1.0
+ */
+gboolean
+epc_app_filter_is_flatpak_ref_allowed (EpcAppFilter *filter,
+                                       const gchar  *app_ref)
+{
+  g_return_val_if_fail (filter != NULL, FALSE);
+  g_return_val_if_fail (filter->ref_count >= 1, FALSE);
+  g_return_val_if_fail (app_ref != NULL, FALSE);
+
+  gboolean ref_in_list = g_strv_contains ((const gchar * const *) filter->app_list,
+                                          app_ref);
+
+  switch (filter->app_list_type)
+    {
+    case EPC_APP_FILTER_LIST_BLACKLIST:
+      return !ref_in_list;
+    case EPC_APP_FILTER_LIST_WHITELIST:
+      return ref_in_list;
+    default:
+      g_assert_not_reached ();
+    }
+}
+
 /**
  * epc_app_filter_get_oars_value:
  * @filter: an #EpcAppFilter
@@ -977,6 +1011,32 @@ epc_app_filter_builder_blacklist_path (EpcAppFilterBuilder *builder,
     g_ptr_array_add (_builder->paths_blacklist, g_steal_pointer (&canonical_path));
 }
 
+/**
+ * epc_app_filter_builder_blacklist_flatpak_ref:
+ * @builder: an initialised #EpcAppFilterBuilder
+ * @app_ref: a flatpak app ref to blacklist
+ *
+ * Add @app_ref to the blacklist of flatpak refs in the filter under
+ * construction. The @app_ref will not be added again if it’s already been
+ * added.
+ *
+ * Since: 0.1.0
+ */
+void
+epc_app_filter_builder_blacklist_flatpak_ref (EpcAppFilterBuilder *builder,
+                                              const gchar         *app_ref)
+{
+  EpcAppFilterBuilderReal *_builder = (EpcAppFilterBuilderReal *) builder;
+
+  g_return_if_fail (_builder != NULL);
+  g_return_if_fail (_builder->paths_blacklist != NULL);
+  g_return_if_fail (app_ref != NULL);
+
+  if (!g_ptr_array_find_with_equal_func (_builder->paths_blacklist,
+                                         app_ref, g_str_equal, NULL))
+    g_ptr_array_add (_builder->paths_blacklist, g_strdup (app_ref));
+}
+
 /**
  * epc_app_filter_builder_set_oars_value:
  * @builder: an initialised #EpcAppFilterBuilder

libeos-parental-controls/app-filter.h

@@ -100,6 +100,8 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC (EpcAppFilter, epc_app_filter_unref)
 uid_t    epc_app_filter_get_user_id            (EpcAppFilter *filter);
 gboolean epc_app_filter_is_path_allowed        (EpcAppFilter *filter,
                                                 const gchar  *path);
+gboolean epc_app_filter_is_flatpak_ref_allowed (EpcAppFilter *filter,
+                                                const gchar  *flatpak_ref);
 
 EpcAppFilterOarsValue epc_app_filter_get_oars_value (EpcAppFilter *filter,
                                                      const gchar  *oars_section);
@@ -179,6 +181,8 @@ EpcAppFilter *epc_app_filter_builder_end (EpcAppFilterBuilder *builder);
 
 void epc_app_filter_builder_blacklist_path        (EpcAppFilterBuilder   *builder,
                                                    const gchar           *path);
+void epc_app_filter_builder_blacklist_flatpak_ref (EpcAppFilterBuilder *builder,
+                                                   const gchar         *app_ref);
 void epc_app_filter_builder_set_oars_value        (EpcAppFilterBuilder   *builder,
                                                    const gchar           *oars_section,
                                                    EpcAppFilterOarsValue  value);

libeos-parental-controls/tests/app-filter.c

@@ -102,6 +102,9 @@ test_app_filter_builder_non_empty (BuilderFixture *fixture,
   epc_app_filter_builder_blacklist_path (fixture->builder, "/bin/true");
   epc_app_filter_builder_blacklist_path (fixture->builder, "/usr/bin/gnome-software");
 
+  epc_app_filter_builder_blacklist_flatpak_ref (fixture->builder,
+                                                "app/org.doom.Doom/x86_64/master");
+
   epc_app_filter_builder_set_oars_value (fixture->builder, "drugs-alcohol",
                                          EPC_APP_FILTER_OARS_VALUE_MILD);
   epc_app_filter_builder_set_oars_value (fixture->builder, "language-humor",
@@ -113,6 +116,11 @@ test_app_filter_builder_non_empty (BuilderFixture *fixture,
   g_assert_false (epc_app_filter_is_path_allowed (filter,
                                                   "/usr/bin/gnome-software"));
 
+  g_assert_true (epc_app_filter_is_flatpak_ref_allowed (filter,
+                                                        "app/org.gnome.Ponies/x86_64/master"));
+  g_assert_false (epc_app_filter_is_flatpak_ref_allowed (filter,
+                                                         "app/org.doom.Doom/x86_64/master"));
+
   g_assert_cmpint (epc_app_filter_get_oars_value (filter, "drugs-alcohol"), ==,
                    EPC_APP_FILTER_OARS_VALUE_MILD);
   g_assert_cmpint (epc_app_filter_get_oars_value (filter, "language-humor"), ==,
@@ -134,6 +142,11 @@ test_app_filter_builder_empty (BuilderFixture *fixture,
   g_assert_true (epc_app_filter_is_path_allowed (filter,
                                                  "/usr/bin/gnome-software"));
 
+  g_assert_true (epc_app_filter_is_flatpak_ref_allowed (filter,
+                                                        "app/org.gnome.Ponies/x86_64/master"));
+  g_assert_true (epc_app_filter_is_flatpak_ref_allowed (filter,
+                                                        "app/org.doom.Doom/x86_64/master"));
+
   g_assert_cmpint (epc_app_filter_get_oars_value (filter, "drugs-alcohol"), ==,
                    EPC_APP_FILTER_OARS_VALUE_UNKNOWN);
   g_assert_cmpint (epc_app_filter_get_oars_value (filter, "language-humor"), ==,