On Wed, Feb 8, 2023 at 7:42 PM Marco Elver <elver@xxxxxxxxxx> wrote: > > Clang 15 will provide an option to prefix calls to memcpy/memset/memmove > with __asan_ in instrumented functions: https://reviews.llvm.org/D122724 Hi Marco, Does this option affect all functions or only the ones that are marked with no_sanitize? Based on the LLVM patch description, should we also change the normal memcpy/memset/memmove to be noninstrumented? These __asan_mem* functions are not defined in the kernel AFAICS. Should we add them? Or maybe we should just use "__" as the prefix, as right now __mem* functions are the ones that are not instrumented? Thanks! > GCC does not yet have similar support. > > 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> > --- > > The Fixes tag is just there to show the dependency, and that people > shouldn't apply this patch without 69d4c0d32186. > > --- > scripts/Makefile.kasan | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan > index b9e94c5e7097..78336b04c077 100644 > --- a/scripts/Makefile.kasan > +++ b/scripts/Makefile.kasan > @@ -38,6 +38,13 @@ endif > > CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable)) > > +ifdef CONFIG_GENERIC_ENTRY > +# 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. > +CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix) > +endif > + > endif # CONFIG_KASAN_GENERIC > > ifdef CONFIG_KASAN_SW_TAGS > -- > 2.39.1.519.gcb327c4b5f-goog >
