From 8fc31e80652b073dfad49a57f925663db8d618eb Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Tue, 1 Mar 2022 17:36:12 +0000 Subject: [PATCH] cheri: don't use dl_random for pointer mangling Pointer mangling cannot be supported on capability architectures. And there is not enough bytes in dl_random for 128 bit pointers. Stack guard is still loaded from dl_random: stack protection is unlikely to be useful on a capability architecture, but it works. --- sysdeps/unix/sysv/linux/dl-osinfo.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/sysdeps/unix/sysv/linux/dl-osinfo.h b/sysdeps/unix/sysv/linux/dl-osinfo.h index 49d8f973c81..c5d864f5ba9 100644 --- a/sysdeps/unix/sysv/linux/dl-osinfo.h +++ b/sysdeps/unix/sysv/linux/dl-osinfo.h @@ -52,7 +52,12 @@ _dl_setup_stack_chk_guard (void *dl_random) static inline uintptr_t __attribute__ ((always_inline)) _dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard) { +#ifdef __CHERI_PURE_CAPABILITY__ + /* Pointer mangling is not supported on capability architectures. */ + return 0; +#else uintptr_t ret; memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret)); return ret; +#endif } -- 2.47.2