Ensure that KMSAN builds replace memset/memcpy/memmove calls with the respective __msan_XXX functions, and that none of the macros are redefined twice. This should allow building kernel with both CONFIG_KMSAN and CONFIG_FORTIFY_SOURCE. Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Nathan Chancellor <nathan@xxxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Reported-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxxxxx> Link: https://github.com/google/kmsan/issues/89 Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> --- arch/x86/include/asm/string_64.h | 11 +++++++---- include/linux/fortify-string.h | 17 +++++++++++++++-- include/linux/kmsan_string.h | 21 +++++++++++++++++++++ mm/kmsan/instrumentation.c | 1 + 4 files changed, 44 insertions(+), 6 deletions(-) create mode 100644 include/linux/kmsan_string.h diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h index 3b87d889b6e16..888731ccf1f67 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -10,10 +10,13 @@ /* Even with __builtin_ the compiler may decide to use the out of line function. */ +#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY) +#include <linux/kmsan_string.h> +#endif + #define __HAVE_ARCH_MEMCPY 1 -#if defined(__SANITIZE_MEMORY__) +#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY) #undef memcpy -void *__msan_memcpy(void *dst, const void *src, size_t size); #define memcpy __msan_memcpy #else extern void *memcpy(void *to, const void *from, size_t len); @@ -21,7 +24,7 @@ extern void *memcpy(void *to, const void *from, size_t len); extern void *__memcpy(void *to, const void *from, size_t len); #define __HAVE_ARCH_MEMSET -#if defined(__SANITIZE_MEMORY__) +#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY) extern void *__msan_memset(void *s, int c, size_t n); #undef memset #define memset __msan_memset @@ -67,7 +70,7 @@ static inline void *memset64(uint64_t *s, uint64_t v, size_t n) } #define __HAVE_ARCH_MEMMOVE -#if defined(__SANITIZE_MEMORY__) +#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY) #undef memmove void *__msan_memmove(void *dest, const void *src, size_t len); #define memmove __msan_memmove diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index 4029fe368a4f6..18a31b125f9d6 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -43,11 +43,24 @@ extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen); extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat); extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy); #else -#define __underlying_memchr __builtin_memchr -#define __underlying_memcmp __builtin_memcmp + +#if defined(__SANITIZE_MEMORY__) +/* + * For KMSAN builds all memcpy/memset/memmove calls should be replaced by the + * corresponding __msan_XXX functions. + */ +#include <linux/kmsan_string.h> +#define __underlying_memcpy __msan_memcpy +#define __underlying_memmove __msan_memmove +#define __underlying_memset __msan_memset +#else #define __underlying_memcpy __builtin_memcpy #define __underlying_memmove __builtin_memmove #define __underlying_memset __builtin_memset +#endif + +#define __underlying_memchr __builtin_memchr +#define __underlying_memcmp __builtin_memcmp #define __underlying_strcat __builtin_strcat #define __underlying_strcpy __builtin_strcpy #define __underlying_strlen __builtin_strlen diff --git a/include/linux/kmsan_string.h b/include/linux/kmsan_string.h new file mode 100644 index 0000000000000..7287da6f52eff --- /dev/null +++ b/include/linux/kmsan_string.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KMSAN string functions API used in other headers. + * + * Copyright (C) 2022 Google LLC + * Author: Alexander Potapenko <glider@xxxxxxxxxx> + * + */ +#ifndef _LINUX_KMSAN_STRING_H +#define _LINUX_KMSAN_STRING_H + +/* + * KMSAN overrides the default memcpy/memset/memmove implementations in the + * kernel, which requires having __msan_XXX function prototypes in several other + * headers. Keep them in one place instead of open-coding. + */ +void *__msan_memcpy(void *dst, const void *src, size_t size); +void *__msan_memset(void *s, int c, size_t n); +void *__msan_memmove(void *dest, const void *src, size_t len); + +#endif /* _LINUX_KMSAN_STRING_H */ diff --git a/mm/kmsan/instrumentation.c b/mm/kmsan/instrumentation.c index 280d154132684..271f135f97a16 100644 --- a/mm/kmsan/instrumentation.c +++ b/mm/kmsan/instrumentation.c @@ -14,6 +14,7 @@ #include "kmsan.h" #include <linux/gfp.h> +#include <linux/kmsan_string.h> #include <linux/mm.h> #include <linux/uaccess.h> -- 2.38.0.135.g90850a2211-goog
