On Mon, Feb 13, 2023 at 09:13:35PM +0100, Marco Elver wrote: > Clang 15 will provide an option to prefix calls to memcpy/memset/memmove > with __asan_ 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> Thanks! Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > --- > v3: > * Resend with actual fix. > > 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. > --- > scripts/Makefile.kasan | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan > index b9e94c5e7097..3b35a88af60d 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=1) > +endif > + > endif # CONFIG_KASAN_GENERIC > > ifdef CONFIG_KASAN_SW_TAGS > -- > 2.39.1.581.gbfd45094c4-goog >
