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 <[email protected]>
diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 605050c..187cd9b 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -52,6 +52,8 @@
#include <linux/ide.h>
#endif
+#include "lkdtm.h"
+
/*
* Make sure our attempts to over run the kernel stack doesn't trigger
* a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
@@ -103,6 +105,7 @@
CT_EXEC_STACK,
CT_EXEC_KMALLOC,
CT_EXEC_VMALLOC,
+ CT_EXEC_RODATA,
CT_EXEC_USERSPACE,
CT_ACCESS_USERSPACE,
CT_WRITE_RO,
@@ -145,6 +148,7 @@
"EXEC_STACK",
"EXEC_KMALLOC",
"EXEC_VMALLOC",
+ "EXEC_RODATA",
"EXEC_USERSPACE",
"ACCESS_USERSPACE",
"WRITE_RO",
@@ -346,15 +350,18 @@
memset((void *)data, 0, 64);
}
-static void noinline execute_location(void *dst)
+static noinline void execute_location(void *dst, bool write)
{
void (*func)(void) = dst;
pr_info("attempting ok execution at %p\n", do_nothing);
do_nothing();
- memcpy(dst, do_nothing, EXEC_SIZE);
- flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
+ if (write) {
+ memcpy(dst, do_nothing, EXEC_SIZE);
+ flush_icache_range((unsigned long)dst,
+ (unsigned long)dst + EXEC_SIZE);
+ }
pr_info("attempting bad execution at %p\n", func);
func();
}
@@ -551,25 +558,28 @@
schedule();
break;
case CT_EXEC_DATA:
- execute_location(data_area);
+ execute_location(data_area, true);
break;
case CT_EXEC_STACK: {
u8 stack_area[EXEC_SIZE];
- execute_location(stack_area);
+ execute_location(stack_area, true);
break;
}
case CT_EXEC_KMALLOC: {
u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
- execute_location(kmalloc_area);
+ execute_location(kmalloc_area, true);
kfree(kmalloc_area);
break;
}
case CT_EXEC_VMALLOC: {
u32 *vmalloc_area = vmalloc(EXEC_SIZE);
- execute_location(vmalloc_area);
+ execute_location(vmalloc_area, true);
vfree(vmalloc_area);
break;
}
+ case CT_EXEC_RODATA:
+ execute_location(lkdtm_rodata_do_nothing, false);
+ break;
case CT_EXEC_USERSPACE: {
unsigned long user_addr;
