x86: kmsan: use __msan_ string functions where possible.

Unless stated otherwise (by explicitly calling __memcpy(), __memset() or
__memmove()) we want all string functions to call their __msan_ versions
(e.g.  __msan_memcpy() instead of memcpy()), so that shadow and origin
values are updated accordingly.

Bootloader must still use the default string functions to avoid crashes.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ilya Leoshkevich <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vegard Nossum <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

2 files changed, 23 insertions, 2 deletions

diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 6e450827f677..3b87d889b6e1 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -11,11 +11,23 @@
    function. */
 
 #define __HAVE_ARCH_MEMCPY 1
+#if defined(__SANITIZE_MEMORY__)
+#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);
+#endif
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #define __HAVE_ARCH_MEMSET
+#if defined(__SANITIZE_MEMORY__)
+extern void *__msan_memset(void *s, int c, size_t n);
+#undef memset
+#define memset __msan_memset
+#else
 void *memset(void *s, int c, size_t n);
+#endif
 void *__memset(void *s, int c, size_t n);
 
 #define __HAVE_ARCH_MEMSET16
@@ -55,7 +67,13 @@ static inline void *memset64(uint64_t *s, uint64_t v, size_t n)
 }
 
 #define __HAVE_ARCH_MEMMOVE
+#if defined(__SANITIZE_MEMORY__)
+#undef memmove
+void *__msan_memmove(void *dest, const void *src, size_t len);
+#define memmove __msan_memmove
+#else
 void *memmove(void *dest, const void *src, size_t count);
+#endif
 void *__memmove(void *dest, const void *src, size_t count);
 
 int memcmp(const void *cs, const void *ct, size_t count);
@@ -64,8 +82,7 @@ char *strcpy(char *dest, const char *src);
 char *strcat(char *dest, const char *src);
 int strcmp(const char *cs, const char *ct);
 
-#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
-
+#if (defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__))
 /*
  * For files that not instrumented (e.g. mm/slub.c) we
  * should use not instrumented version of mem* functions.
@@ -73,7 +90,9 @@ int strcmp(const char *cs, const char *ct);
 
 #undef memcpy
 #define memcpy(dst, src, len) __memcpy(dst, src, len)
+#undef memmove
 #define memmove(dst, src, len) __memmove(dst, src, len)
+#undef memset
 #define memset(s, c, n) __memset(s, c, n)
 
 #ifndef __NO_FORTIFY
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index 3b401fa0f374..6c8a1a29d0b6 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -285,8 +285,10 @@ __FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size,
  * __builtin_object_size() must be captured here to avoid evaluating argument
  * side-effects further into the macro layers.
  */
+#ifndef CONFIG_KMSAN
 #define memset(p, c, s) __fortify_memset_chk(p, c, s,			\
 		__builtin_object_size(p, 0), __builtin_object_size(p, 1))
+#endif
 
 /*
  * To make sure the compiler can enforce protection against buffer overflows,