Add generic static permissions to metadata

This allows you do do something like
  flatpak build-finish --add-policy=subsystem.key=v1 --add-policy=subsystem.key=v2

Which maps to this metadata keys:

[Policy subsystem]
key=v1;v2;

You can also --remove-policy to remove values from a key.

The policy values are parsed from the app and runtime metadata, and
are overridable by per-app overrides and on the command line, however
the values are never used by flatpak. They do end up in the flatpak-info
file for the running application though, so external agents can look
at them.

These

common/flatpak-run.c

@@ -130,6 +130,7 @@ struct FlatpakContext
   GHashTable           *filesystems;
   GHashTable           *session_bus_policy;
   GHashTable           *system_bus_policy;
+  GHashTable           *generic_policy;
 };
 
 FlatpakContext *
@@ -143,6 +144,8 @@ flatpak_context_new (void)
   context->filesystems = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
   context->session_bus_policy = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
   context->system_bus_policy = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+  context->generic_policy = g_hash_table_new_full (g_str_hash, g_str_equal,
+                                                   g_free, (GDestroyNotify)g_strfreev);
 
   return context;
 }
@@ -155,6 +158,7 @@ flatpak_context_free (FlatpakContext *context)
   g_hash_table_destroy (context->filesystems);
   g_hash_table_destroy (context->session_bus_policy);
   g_hash_table_destroy (context->system_bus_policy);
+  g_hash_table_destroy (context->generic_policy);
   g_slice_free (FlatpakContext, context);
 }
 
@@ -477,6 +481,38 @@ flatpak_context_set_system_bus_policy (FlatpakContext *context,
   g_hash_table_insert (context->system_bus_policy, g_strdup (name), GINT_TO_POINTER (policy));
 }
 
+void
+flatpak_context_apply_generic_policy (FlatpakContext *context,
+                                      const char     *key,
+                                      const char     *value)
+{
+  GPtrArray *new = g_ptr_array_new ();
+  const char **old_v;
+  int i;
+
+  g_assert (strchr (key, '.') != NULL);
+
+  old_v = g_hash_table_lookup (context->generic_policy, key);
+  for (i = 0; old_v != NULL && old_v[i] != NULL; i++)
+    {
+      const char *old = old_v[i];
+      const char *cmp1 = old;
+      const char *cmp2 = value;
+      if (*cmp1 == '!')
+        cmp1++;
+      if (*cmp2 == '!')
+        cmp2++;
+      if (strcmp (cmp1, cmp2) != 0)
+        g_ptr_array_add (new, g_strdup (old));
+    }
+
+  g_ptr_array_add (new, g_strdup (value));
+  g_ptr_array_add (new, NULL);
+
+  g_hash_table_insert (context->generic_policy, g_strdup (key),
+                       g_ptr_array_free (new, FALSE));
+}
+
 static void
 flatpak_context_set_persistent (FlatpakContext *context,
                                 const char     *path)
@@ -693,6 +729,21 @@ flatpak_context_merge (FlatpakContext *context,
   g_hash_table_iter_init (&iter, other->system_bus_policy);
   while (g_hash_table_iter_next (&iter, &key, &value))
     g_hash_table_insert (context->system_bus_policy, g_strdup (key), value);
+
+  g_hash_table_iter_init (&iter, other->system_bus_policy);
+  while (g_hash_table_iter_next (&iter, &key, &value))
+    g_hash_table_insert (context->system_bus_policy, g_strdup (key), value);
+
+  g_hash_table_iter_init (&iter, other->generic_policy);
+  while (g_hash_table_iter_next (&iter, &key, &value))
+    {
+      const char **policy_values = (const char **)value;
+      int i;
+
+      for (i = 0; policy_values[i] != NULL; i++)
+        flatpak_context_apply_generic_policy (context, (char *)key, policy_values[i]);
+    }
+
 }
 
 static gboolean
@@ -950,6 +1001,63 @@ option_system_talk_name_cb (const gchar *option_name,
   return TRUE;
 }
 
+static gboolean
+option_add_generic_policy_cb (const gchar *option_name,
+                              const gchar *value,
+                              gpointer     data,
+                              GError     **error)
+{
+  FlatpakContext *context = data;
+  char *t;
+  g_autofree char *key = NULL;
+  const char *policy_value;
+
+  t = strchr (value, '=');
+  if (t == NULL)
+    return flatpak_fail (error, "--policy arguments must be in the form SUBSYSTEM.KEY=[!]VALUE");
+  policy_value = t + 1;
+  key = g_strndup (value, t - value);
+  if (strchr (key, '.') == NULL)
+    return flatpak_fail (error, "--policy arguments must be in the form SUBSYSTEM.KEY=[!]VALUE");
+
+  if (policy_value[0] == '!')
+    return flatpak_fail (error, "--policy values can't start with \"!\"");
+
+  flatpak_context_apply_generic_policy (context, key, policy_value);
+
+  return TRUE;
+}
+
+static gboolean
+option_remove_generic_policy_cb (const gchar *option_name,
+                                 const gchar *value,
+                                 gpointer     data,
+                                 GError     **error)
+{
+  FlatpakContext *context = data;
+  char *t;
+  g_autofree char *key = NULL;
+  const char *policy_value;
+  g_autofree char *extended_value = NULL;
+
+  t = strchr (value, '=');
+  if (t == NULL)
+    return flatpak_fail (error, "--policy arguments must be in the form SUBSYSTEM.KEY=[!]VALUE");
+  policy_value = t + 1;
+  key = g_strndup (value, t - value);
+  if (strchr (key, '.') == NULL)
+    return flatpak_fail (error, "--policy arguments must be in the form SUBSYSTEM.KEY=[!]VALUE");
+
+  if (policy_value[0] == '!')
+    return flatpak_fail (error, "--policy values can't start with \"!\"");
+
+  extended_value = g_strconcat ("!", policy_value, NULL);
+
+  flatpak_context_apply_generic_policy (context, key, extended_value);
+
+  return TRUE;
+}
+
 static gboolean
 option_persist_cb (const gchar *option_name,
                    const gchar *value,
@@ -980,6 +1088,8 @@ static GOptionEntry context_options[] = {
   { "talk-name", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_talk_name_cb, N_("Allow app to talk to name on the session bus"), N_("DBUS_NAME") },
   { "system-own-name", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_system_own_name_cb, N_("Allow app to own name on the system bus"), N_("DBUS_NAME") },
   { "system-talk-name", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_system_talk_name_cb, N_("Allow app to talk to name on the system bus"), N_("DBUS_NAME") },
+  { "add-policy", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_add_generic_policy_cb, N_("Add generic policy option"), N_("SUBSYSTEM.KEY=VALUE") },
+  { "remove-policy", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_remove_generic_policy_cb, N_("Remove generic policy option"), N_("SUBSYSTEM.KEY=VALUE") },
   { "persist", 0, G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_CALLBACK, &option_persist_cb, N_("Persist home directory"), N_("FILENAME") },
   /* This is not needed/used anymore, so hidden, but we accept it for backwards compat */
   { "no-desktop", 0, G_OPTION_FLAG_IN_MAIN |  G_OPTION_FLAG_HIDDEN, G_OPTION_ARG_NONE, &option_no_desktop_deprecated, N_("Don't require a running session (no cgroups creation)"), NULL },
@@ -1031,6 +1141,7 @@ flatpak_context_load_metadata (FlatpakContext *context,
                                GError        **error)
 {
   gboolean remove;
+  g_auto(GStrv) groups = NULL;
   int i;
 
   if (g_key_file_has_key (metakey, FLATPAK_METADATA_GROUP_CONTEXT, FLATPAK_METADATA_KEY_SHARED, NULL))
@@ -1204,6 +1315,33 @@ flatpak_context_load_metadata (FlatpakContext *context,
         }
     }
 
+  groups = g_key_file_get_groups (metakey, NULL);
+  for (i = 0; groups[i] != NULL; i++)
+    {
+      const char *group = groups[i];
+      const char *subsystem;
+      int j;
+
+      if (g_str_has_prefix (group, FLATPAK_METADATA_GROUP_PREFIX_POLICY))
+        {
+          g_auto(GStrv) keys = NULL;
+          subsystem = group + strlen (FLATPAK_METADATA_GROUP_PREFIX_POLICY);
+          keys = g_key_file_get_keys (metakey, group, NULL, NULL);
+          for (j = 0; keys != NULL && keys[j] != NULL; j++)
+            {
+              const char *key = keys[j];
+              g_autofree char *policy_key = g_strdup_printf ("%s.%s", subsystem, key);
+              g_auto(GStrv) values = NULL;
+              int k;
+
+              values = g_key_file_get_string_list (metakey, group, key, NULL, NULL);
+              for (k = 0; values != NULL && values[k] != NULL; k++)
+                flatpak_context_apply_generic_policy (context, policy_key,
+                                                      values[k]);
+            }
+        }
+    }
+
   return TRUE;
 }
 
@@ -1226,6 +1364,8 @@ flatpak_context_save_metadata (FlatpakContext *context,
   FlatpakContextDevices devices_valid = context->devices_valid;
   FlatpakContextFeatures features_mask = context->features;
   FlatpakContextFeatures features_valid = context->features;
+  g_auto(GStrv) groups = NULL;
+  int i;
 
   if (flatten)
     {
@@ -1387,6 +1527,42 @@ flatpak_context_save_metadata (FlatpakContext *context,
                              FLATPAK_METADATA_GROUP_ENVIRONMENT,
                              (char *) key, (char *) value);
     }
+
+
+  groups = g_key_file_get_groups (metakey, NULL);
+  for (i = 0; groups[i] != NULL; i++)
+    {
+      const char *group = groups[i];
+      if (g_str_has_prefix (group, FLATPAK_METADATA_GROUP_PREFIX_POLICY))
+        g_key_file_remove_group (metakey, group, NULL);
+    }
+
+  g_hash_table_iter_init (&iter, context->generic_policy);
+  while (g_hash_table_iter_next (&iter, &key, &value))
+    {
+      g_auto(GStrv) parts = g_strsplit ((const char *)key, ".", 2);
+      g_autofree char *group = NULL;
+      g_assert (parts[1] != NULL);
+      const char **policy_values = (const char **)value;
+      g_autoptr(GPtrArray) new = g_ptr_array_new ();
+
+      for (i = 0; policy_values[i] != NULL; i++)
+        {
+          const char *policy_value = policy_values[i];
+
+          if (!flatten || policy_value[0] != '!')
+            g_ptr_array_add (new, (char *)policy_value);
+        }
+
+      if (new->len > 0)
+        {
+          group = g_strconcat (FLATPAK_METADATA_GROUP_PREFIX_POLICY,
+                               parts[0], NULL);
+          g_key_file_set_string_list (metakey, group, parts[1],
+                                      (const char * const*)new->pdata,
+                                      new->len);
+        }
+    }
 }
 
 void

common/flatpak-run.h

@@ -32,6 +32,7 @@ gboolean flatpak_run_in_transient_unit (const char *app_id,
 #define FLATPAK_METADATA_GROUP_CONTEXT "Context"
 #define FLATPAK_METADATA_GROUP_SESSION_BUS_POLICY "Session Bus Policy"
 #define FLATPAK_METADATA_GROUP_SYSTEM_BUS_POLICY "System Bus Policy"
+#define FLATPAK_METADATA_GROUP_PREFIX_POLICY "Policy "
 #define FLATPAK_METADATA_GROUP_ENVIRONMENT "Environment"
 #define FLATPAK_METADATA_KEY_SHARED "shared"
 #define FLATPAK_METADATA_KEY_SOCKETS "sockets"