[PATCH] lkdtm: cfi: Fix type width for masking PAC bits

From: Kees Cook
Date: Tue Apr 26 2022 - 20:12:43 EST


The masking for PAC bits wasn't handling 32-bit architectures correctly.
Replace the u64 cast with uintptr_t.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/CAMuHMdVz-J-1ZQ08u0bsQihDkcRmEPrtX5B_oRJ+Ns5jrasnUw@xxxxxxxxxxxxxx
Fixes: 2e53b877dc12 ("lkdtm: Add CFI_BACKWARD to test ROP mitigations")
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/misc/lkdtm/cfi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/lkdtm/cfi.c b/drivers/misc/lkdtm/cfi.c
index 804965a480b7..666a7f4bc137 100644
--- a/drivers/misc/lkdtm/cfi.c
+++ b/drivers/misc/lkdtm/cfi.c
@@ -59,7 +59,7 @@ static void lkdtm_CFI_FORWARD_PROTO(void)
#endif

#define no_pac_addr(addr) \
- ((__force __typeof__(addr))((__force u64)(addr) | PAGE_OFFSET))
+ ((__force __typeof__(addr))((uintptr_t)(addr) | PAGE_OFFSET))

/* The ultimate ROP gadget. */
static noinline __no_ret_protection
--
2.32.0