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authorAlexander Potapenko <glider@google.com>2022-10-25 00:21:44 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-10-28 23:37:23 +0300
commit78a498c3a227f2ac773a8234b2ce092a4403f2c3 (patch)
treed7efd152160584209dfcbde2aa4cfaa65f728425
parent59c8a02e24894e75639bcecc3cb1e768a2792220 (diff)
downloadlinux-78a498c3a227f2ac773a8234b2ce092a4403f2c3.tar.xz
x86: fortify: kmsan: fix KMSAN fortify builds
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. Link: https://lkml.kernel.org/r/20221024212144.2852069-5-glider@google.com Link: https://github.com/google/kmsan/issues/89 Signed-off-by: Alexander Potapenko <glider@google.com> Reported-by: Tamas K Lengyel <tamas.lengyel@zentific.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--arch/x86/include/asm/string_64.h11
-rw-r--r--include/linux/fortify-string.h17
-rw-r--r--include/linux/kmsan_string.h21
-rw-r--r--mm/kmsan/instrumentation.c1
4 files changed, 44 insertions, 6 deletions
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 3b87d889b6e1..888731ccf1f6 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 4029fe368a4f..18a31b125f9d 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 000000000000..7287da6f52ef
--- /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@google.com>
+ *
+ */
+#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 280d15413268..271f135f97a1 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>