The -fstack-protector compiler flag will only build stack protections if
a character array is seen. Additionally, the offset to the saved
instruction pointer changes based on architecture, so stomp much harder
(64 bytes) when corrupting the stack.
Signed-off-by: Kees Cook <keesc...@chromium.org>
---
drivers/misc/lkdtm.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 08aad69..adb6bde 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -295,10 +295,10 @@ static void lkdtm_do_action(enum ctype which)
(void) recursive_loop(0);
break;
case CT_CORRUPT_STACK: {
- volatile u32 data[8];
- volatile u32 *p = data;
+ /* Make sure the compiler creates and uses an 8 char array. */
+ volatile char data[8];
- p[12] = 0x12345678;
+ memset((void *)data, 0, 64);
break;
}
case CT_UNALIGNED_LOAD_STORE_WRITE: {
--
1.7.9.5
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