lkdtm: add function for testing .rodata section

This adds a function that lives in the .rodata section. The section
flags are corrected using objcopy since there is no way with gcc to
declare section flags in an architecture-agnostic way.

Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm_rodata.c b/drivers/misc/lkdtm_rodata.c
new file mode 100644
index 000000000000..4d0d851f02b9
--- /dev/null
+++ b/drivers/misc/lkdtm_rodata.c
@@ -0,0 +1,10 @@
+/*
+ * This includes functions that are meant to live entirely in .rodata
+ * (via objcopy tricks), to validate the non-executability of .rodata.
+ */
+#include <linux/kernel.h>
+
+void lkdtm_rodata_do_nothing(void)
+{
+	/* Does nothing. We just want an architecture agnostic "return". */
+}