[PATCH v5 26/38] kmsan: use __msan_ string functions where possible.

[glider@google.com]

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.

Signed-off-by: Alexander Potapenko <glider@google.com>
To: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-mm@kvack.org
---
v3:
 - use default string functions in the bootloader
v4:
 - include kmsan-checks.h into compiler.h
 - also handle memset() and memmove()
 - fix https://github.com/google/kmsan/issues/64
v5:
 - don't compile memset() and memmove() under KMSAN

Change-Id: Ib2512ce5aa8d457453dd38caa12f58f002166813
---
 arch/x86/boot/compressed/misc.h               |  1 +
 arch/x86/include/asm/string_64.h              | 23 ++++++++++++++++++-
 .../firmware/efi/libstub/efi-stub-helper.c    |  5 ++++
 drivers/firmware/efi/libstub/tpm.c            |  5 ++++
 include/linux/compiler.h                      |  9 +++++++-
 include/linux/string.h                        |  2 ++
 6 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index c8181392f70d7..dd4bd8c5d97a1 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -12,6 +12,7 @@
 #undef CONFIG_PARAVIRT_XXL
 #undef CONFIG_PARAVIRT_SPINLOCKS
 #undef CONFIG_KASAN
+#undef CONFIG_KMSAN
 
 /* cpu_feature_enabled() cannot be used this early */
 #define USE_EARLY_PGTABLE_L5
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 75314c3dbe471..0442e679b3079 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(CONFIG_KMSAN)
+#undef memcpy
+/* __msan_memcpy() is defined in compiler.h */
+#define memcpy(dst, src, len) __msan_memcpy(dst, src, len)
+#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(CONFIG_KMSAN)
+extern void *__msan_memset(void *s, int c, size_t n);
+#undef memset
+#define memset(dst, c, len) __msan_memset(dst, c, len)
+#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(CONFIG_KMSAN)
+#undef memmove
+void *__msan_memmove(void *dest, const void *src, size_t len);
+#define memmove(dst, src, len) __msan_memmove(dst, src, len)
+#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);
@@ -64,7 +82,8 @@ 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__)) || \
+	(defined(CONFIG_KMSAN) && !defined(__SANITIZE_MEMORY__))
 
 /*
  * For files that not instrumented (e.g. mm/slub.c) we
@@ -73,7 +92,9 @@ 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/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 9f34c72429397..610f791c2493e 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -5,7 +5,12 @@
  * implementation files.
  *
  * Copyright 2011 Intel Corporation; author Matt Fleming
+ *
+ *
+ * This file is not linked with KMSAN runtime.
+ * Do not replace memcpy with __memcpy.
  */
+#undef CONFIG_KMSAN
 
 #include <linux/efi.h>
 #include <asm/efi.h>
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
index 1d59e103a2e3a..7e8906b1c1c98 100644
--- a/drivers/firmware/efi/libstub/tpm.c
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -6,7 +6,12 @@
  * Copyright (C) 2017 Google, Inc.
  *     Matthew Garrett <mjg59@google.com>
  *     Thiebaud Weksteen <tweek@google.com>
+ *
+ *
+ * This file is not linked with KMSAN runtime.
+ * Do not replace memcpy with __memcpy.
  */
+#undef CONFIG_KMSAN
 #include <linux/efi.h>
 #include <linux/tpm_eventlog.h>
 #include <asm/efi.h>
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c6c67729729e3..f2b97241fe2d4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -180,6 +180,13 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #include <uapi/linux/types.h>
 #include <linux/kcsan-checks.h>
 
+#ifdef CONFIG_KMSAN
+void *__msan_memcpy(void *dst, const void *src, u64 size);
+#define __DO_MEMCPY(res, p, size) __msan_memcpy(res, p, size)
+#else
+#define __DO_MEMCPY(res, p, size) __builtin_memcpy(res, p, size)
+#endif
+
 #define __READ_ONCE_SIZE						\
 ({									\
 	switch (size) {							\
@@ -189,7 +196,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 	case 8: *(__u64 *)res = *(volatile __u64 *)p; break;		\
 	default:							\
 		barrier();						\
-		__builtin_memcpy((void *)res, (const void *)p, size);	\
+		__DO_MEMCPY((void *)res, (const void *)p, size);	\
 		barrier();						\
 	}								\
 })
diff --git a/include/linux/string.h b/include/linux/string.h
index 6dfbb2efa8157..7ef92817c082f 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -356,6 +356,7 @@ __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 	return p;
 }
 
+#ifndef CONFIG_KMSAN
 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 {
 	size_t p_size = __builtin_object_size(p, 0);
@@ -395,6 +396,7 @@ __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
 		fortify_panic(__func__);
 	return __builtin_memmove(p, q, size);
 }
+#endif
 
 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
-- 
2.25.1.696.g5e7596f4ac-goog