[03/18] randstruct: Set designated_init attribute

Commit Message

Kees Cook April 6, 2017, 9:18 p.m. UTC

Since randomized structures need designated initializers, make
sure the designated_init attribute is set for GCC 5.1 and later's
-Werror=designated-init. Since this marking is needed for both manually
and automatically identified structures, have the plugin perform the
marking when active, otherwise fall back to just the manually marked
structures.

Signed-off-by: Kees Cook <[e-mail]>
---
 include/linux/compiler.h                      | 2 +-
 scripts/gcc-plugins/randomize_layout_plugin.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 40e584448605..105410d776a6 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -449,7 +449,7 @@  static __always_inline void __write_once_size(volatile void *p, void *res, int s
 #endif
 
 #ifndef __randomize_layout
-# define __randomize_layout
+# define __randomize_layout __designated_init
 #endif
 
 #ifndef __no_randomize_layout
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index eb8ac6cc315e..6e5dccc4f221 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -377,6 +377,7 @@  static int relayout_struct(tree type)
 		TYPE_FIELDS(variant) = list;
 		TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
 		TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
+		TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant));
 		if (has_flexarray)
 			TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type));
 	}