3 files changed, 19 insertions, 2 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 4ada3209146a..596f0e66e69f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -458,6 +458,13 @@ config GCC_PLUGIN_STRUCTLEAK
            * https://grsecurity.net/
            * https://pax.grsecurity.net/
 
+config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
+        bool "Force initialize all struct type variables passed by reference"
+        depends on GCC_PLUGIN_STRUCTLEAK
+        help
+          Zero initialize any struct type local variable that may be passed by
+          reference without having been initialized.
+
 config GCC_PLUGIN_STRUCTLEAK_VERBOSE
         bool "Report forcefully initialized variables"
         depends on GCC_PLUGIN_STRUCTLEAK
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 2e0e2eaa397f..d1f7b0d6be66 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -27,6 +27,7 @@ ifdef CONFIG_GCC_PLUGINS
 
   gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)    += structleak_plugin.so
   gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE)     += -fplugin-arg-structleak_plugin-verbose
+  gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL)   += -fplugin-arg-structleak_plugin-byref-all
   gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK)     += -DSTRUCTLEAK_PLUGIN
 
   gcc-plugin-$(CONFIG_GCC_PLUGIN_RANDSTRUCT)    += randomize_layout_plugin.so
diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c
index fa3d7a4b26f2..3f8dd4868178 100644
--- a/scripts/gcc-plugins/structleak_plugin.c
+++ b/scripts/gcc-plugins/structleak_plugin.c
@@ -16,6 +16,7 @@
  * Options:
  * -fplugin-arg-structleak_plugin-disable
  * -fplugin-arg-structleak_plugin-verbose
+ * -fplugin-arg-structleak_plugin-byref-all
  *
  * Usage:
  * $ # for 4.5/4.6/C based 4.7
@@ -42,6 +43,7 @@ static struct plugin_info structleak_plugin_info = {
 };
 
 static bool verbose;
+static bool byref_all;
 
 static tree handle_user_attribute(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
 {
@@ -150,7 +152,9 @@ static void initialize(tree var)
         /* these aren't the 0days you're looking for */
         if (verbose)
                 inform(DECL_SOURCE_LOCATION(var),
-                        "userspace variable will be forcibly initialized");
+                        "%s variable will be forcibly initialized",
+                        (byref_all && TREE_ADDRESSABLE(var)) ? "byref"
+                                                             : "userspace");
 
         /* build the initializer expression */
         initializer = build_constructor(TREE_TYPE(var), NULL);
@@ -190,7 +194,8 @@ static unsigned int structleak_execute(void)
                         continue;
 
                 /* if the type is of interest, examine the variable */
-                if (TYPE_USERSPACE(type))
+                if (TYPE_USERSPACE(type) ||
+                    (byref_all && TREE_ADDRESSABLE(var)))
                         initialize(var);
         }
 
@@ -232,6 +237,10 @@ __visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gc
                         verbose = true;
                         continue;
                 }
+                if (!strcmp(argv[i].key, "byref-all")) {
+                        byref_all = true;
+                        continue;
+                }
                 error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
         }