From 51287dcb00cc715c27bf6a6b4dbd431621c5b65a Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Fri, 24 Feb 2023 09:59:39 +0100 Subject: [PATCH] kasan: emit different calls for instrumentable memintrinsics Clang 15 provides an option to prefix memcpy/memset/memmove calls with __asan_/__hwasan_ in instrumented functions: https://reviews.llvm.org/D122724 GCC will add support in future: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108777 Use it to regain KASAN instrumentation of memcpy/memset/memmove on architectures that require noinstr to be really free from instrumented mem*() functions (all GENERIC_ENTRY architectures). Link: https://lkml.kernel.org/r/20230224085942.1791837-1-elver@google.com Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Signed-off-by: Marco Elver Acked-by: Peter Zijlstra (Intel) Reviewed-by: Andrey Konovalov Tested-by: Linux Kernel Functional Testing Tested-by: Naresh Kamboju Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Borislav Petkov (AMD) Cc: Dave Hansen Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Jakub Jelinek Cc: kasan-dev@googlegroups.com Cc: Kees Cook Cc: Linux Kernel Functional Testing Cc: Nathan Chancellor # build only Cc: Nick Desaulniers Cc: Nicolas Schier Cc: Thomas Gleixner Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- mm/kasan/kasan.h | 4 ++++ mm/kasan/shadow.c | 11 +++++++++++ scripts/Makefile.kasan | 8 ++++++++ 3 files changed, 23 insertions(+) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 9377b0789edc..a61eeee3095a 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -666,4 +666,8 @@ void __hwasan_storeN_noabort(unsigned long addr, size_t size); void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size); +void *__hwasan_memset(void *addr, int c, size_t len); +void *__hwasan_memmove(void *dest, const void *src, size_t len); +void *__hwasan_memcpy(void *dest, const void *src, size_t len); + #endif /* __MM_KASAN_KASAN_H */ diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index 3703983a8e55..90186122b21b 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -107,6 +107,17 @@ void *__asan_memcpy(void *dest, const void *src, size_t len) } EXPORT_SYMBOL(__asan_memcpy); +#ifdef CONFIG_KASAN_SW_TAGS +void *__hwasan_memset(void *addr, int c, size_t len) __alias(__asan_memset); +EXPORT_SYMBOL(__hwasan_memset); +#ifdef __HAVE_ARCH_MEMMOVE +void *__hwasan_memmove(void *dest, const void *src, size_t len) __alias(__asan_memmove); +EXPORT_SYMBOL(__hwasan_memmove); +#endif +void *__hwasan_memcpy(void *dest, const void *src, size_t len) __alias(__asan_memcpy); +EXPORT_SYMBOL(__hwasan_memcpy); +#endif + void kasan_poison(const void *addr, size_t size, u8 value, bool init) { void *shadow_start, *shadow_end; diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index b9e94c5e7097..fa9f836f8039 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -38,6 +38,11 @@ endif CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable)) +# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*() +# instead. With compilers that don't support this option, compiler-inserted +# memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures. +CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1) + endif # CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_SW_TAGS @@ -54,6 +59,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \ $(call cc-param,hwasan-inline-all-checks=0) \ $(instrumentation_flags) +# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*(). +CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1) + endif # CONFIG_KASAN_SW_TAGS export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE