On Fri, Feb 17, 2023 at 12:45 AM Marco Elver <elver@xxxxxxxxxx> wrote: > > 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 > Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
