This enables the automatic structure selection logic in the randstruct
GCC plugin. The selection logic randomizes all structures that contain
only function pointers, unless marked with __no_randomize_layout.
Signed-off-by: Kees Cook <keesc...@chromium.org>
---
arch/Kconfig | 12 +++++++-----
scripts/gcc-plugins/randomize_layout_plugin.c | 3 ---
2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 3eac97a4c7b3..f4597dbd0631 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -448,11 +448,13 @@ config GCC_PLUGIN_RANDSTRUCT
depends on GCC_PLUGINS
select MODVERSIONS if MODULES
help
- If you say Y here, the layouts of structures explicitly
- marked by __randomize_layout will be randomized at
- compile-time. This can introduce the requirement of an
- additional information exposure vulnerability for exploits
- targeting these structure types.
+ If you say Y here, the layouts of structures that are entirely
+ function pointers (and have not been manually annotated with
+ __no_randomize_layout), or structures that have been explicitly
+ marked with __randomize_layout, will be randomized at compile-time.
+ This can introduce the requirement of an additional information
+ exposure vulnerability for exploits targeting these structure
+ types.
Enabling this feature will introduce some performance impact,
slightly increase memory usage, and prevent the use of forensic
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c
b/scripts/gcc-plugins/randomize_layout_plugin.c
index e6e02a40d522..bb2c6789c4b7 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -437,9 +437,6 @@ static int is_pure_ops_struct(const_tree node)
gcc_assert(TREE_CODE(node) == RECORD_TYPE || TREE_CODE(node) ==
UNION_TYPE);
- /* XXX: Do not apply randomization to all-ftpr structs yet. */
- return 0;
-
for (field = TYPE_FIELDS(node); field; field = TREE_CHAIN(field)) {
const_tree fieldtype = get_field_type(field);
enum tree_code code = TREE_CODE(fieldtype);
--
2.7.4
