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). Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- v4: * Also enable it for KASAN_SW_TAGS (__hwasan_mem*). v3: * No change. v2: * Use asan-kernel-mem-intrinsic-prefix=1, so that once GCC supports the param, it also works there (it needs the =1). The Fixes tag is just there to show the dependency, and that people shouldn't apply this patch without 69d4c0d32186. --- 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 71c15438afcf..172713b87556 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -637,4 +637,8 @@ 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 98269936a5e4..f8a47cb299cb 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 -- 2.39.2.637.g21b0678d19-goog
