On Fri, 28 Aug, at 02:09:59PM, Andrey Ryabinin wrote: > In not-instrumented code KASAN replaces instrumented > memset/memcpy/memmove with not-instrumented analogues > __memset/__memcpy/__memove. > However, on x86 the EFI stub is not linked with the kernel. > It uses not-instrumented mem*() functions from > arch/x86/boot/compressed/string.c > So we don't replace them with __mem*() variants in EFI stub. > > On ARM64 the EFI stub is linked with the kernel, so we should > replace mem*() functions with __mem*(), because the EFI stub > runs before KASAN sets up early shadow. > > So let's move these #undef mem* into arch's asm/efi.h which is > also included by the EFI stub. > > Signed-off-by: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> > --- > arch/x86/include/asm/efi.h | 11 +++++++++++ > drivers/firmware/efi/libstub/efistub.h | 4 ---- > 2 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h > index 155162e..6862f11 100644 > --- a/arch/x86/include/asm/efi.h > +++ b/arch/x86/include/asm/efi.h > @@ -25,6 +25,17 @@ > #define EFI32_LOADER_SIGNATURE "EL32" > #define EFI64_LOADER_SIGNATURE "EL64" > > +/* > + * Sometimes we may redefine memset to __memset. > + * The EFI stub doesn't have __memset() because it's not > + * linked with the kernel. So we should use standard > + * memset from arch/x86/boot/compressed/string.c > + * The same applies to memcpy and memmove. > + */ > +#undef memcpy > +#undef memset > +#undef memmove > + I think the key piece of information missing in this comment is that it's redefined for KASAN, right? > #ifdef CONFIG_X86_32 > > > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h > index e334a01..6b6548f 100644 > --- a/drivers/firmware/efi/libstub/efistub.h > +++ b/drivers/firmware/efi/libstub/efistub.h > @@ -5,10 +5,6 @@ > /* error code which can't be mistaken for valid address */ > #define EFI_ERROR (~0UL) > > -#undef memcpy > -#undef memset > -#undef memmove > - > void efi_char16_printk(efi_system_table_t *, efi_char16_t *); > > efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg, void *__image, Does this patch have any negative consequences for arm64? Can we safely remove these #undefs without breaking the arm64 EFI stub? -- Matt Fleming, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
