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Date:   Tue, 26 Apr 2022 18:43:10 +0200
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Subject: [PATCH v3 41/46] x86: kmsan: use __msan_ string functions where possible.
From:   Alexander Potapenko <glider@google.com>
To:     glider@google.com
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Christoph Hellwig <hch@lst.de>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Eric Dumazet <edumazet@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Kees Cook <keescook@chromium.org>,
        Marco Elver <elver@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Pekka Enberg <penberg@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vegard Nossum <vegard.nossum@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Precedence: bulk

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>
---

Link: https://linux-review.googlesource.com/id/I7ca9bd6b4f5c9b9816404862ae87ca7984395f33
---
 arch/x86/include/asm/string_64.h | 23 +++++++++++++++++++++--
 include/linux/fortify-string.h   |  2 ++
 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 6e450827f677a..3b87d889b6e16 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 295637a66c46b..fe48f77599e04 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -269,8 +269,10 @@ __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,
-- 
2.36.0.rc2.479.g8af0fa9b8e-goog