Re: [PATCH v3] add the option of fortified string.h functions

From: Kees Cook
Date: Thu May 25 2017 - 23:40:34 EST


On Mon, May 22, 2017 at 4:10 PM, Daniel Micay <danielmicay@xxxxxxxxx> wrote:
> diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
> index 733bae07fb29..3c5b26e07b85 100644
> --- a/arch/x86/include/asm/string_64.h
> +++ b/arch/x86/include/asm/string_64.h
> @@ -77,6 +77,11 @@ int strcmp(const char *cs, const char *ct);
> #define memcpy(dst, src, len) __memcpy(dst, src, len)
> #define memmove(dst, src, len) __memmove(dst, src, len)
> #define memset(s, c, n) __memset(s, c, n)
> +
> +#ifndef __NO_FORTIFY
> +#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
> +#endif
> +
> #endif
>
> #define __HAVE_ARCH_MEMCPY_MCSAFE 1

Ah-ha, this same KASAN exclusion is missing for string_32.h, which is
what I think akpm tripped over in build tests.

-Kees

--
Kees Cook
Pixel Security