s390/kasan: improve string/memory functions checks

Avoid using arch specific implementations of string/memory functions
with KASAN since gcc cannot instrument asm code memory accesses and
many bugs could be missed.
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/string.c

@@ -2,6 +2,7 @@
 #include <linux/ctype.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
+#undef CONFIG_KASAN
 #include "../lib/string.c"
 
 int strncmp(const char *cs, const char *ct, size_t count)

arch/s390/include/asm/string.h

@@ -12,15 +12,21 @@
 #include <linux/types.h>
 #endif
 
-#define __HAVE_ARCH_MEMCHR	/* inline & arch function */
-#define __HAVE_ARCH_MEMCMP	/* arch function */
 #define __HAVE_ARCH_MEMCPY	/* gcc builtin & arch function */
 #define __HAVE_ARCH_MEMMOVE	/* gcc builtin & arch function */
-#define __HAVE_ARCH_MEMSCAN	/* inline & arch function */
 #define __HAVE_ARCH_MEMSET	/* gcc builtin & arch function */
 #define __HAVE_ARCH_MEMSET16	/* arch function */
 #define __HAVE_ARCH_MEMSET32	/* arch function */
 #define __HAVE_ARCH_MEMSET64	/* arch function */
+
+void *memcpy(void *dest, const void *src, size_t n);
+void *memset(void *s, int c, size_t n);
+void *memmove(void *dest, const void *src, size_t n);
+
+#ifndef CONFIG_KASAN
+#define __HAVE_ARCH_MEMCHR	/* inline & arch function */
+#define __HAVE_ARCH_MEMCMP	/* arch function */
+#define __HAVE_ARCH_MEMSCAN	/* inline & arch function */
 #define __HAVE_ARCH_STRCAT	/* inline & arch function */
 #define __HAVE_ARCH_STRCMP	/* arch function */
 #define __HAVE_ARCH_STRCPY	/* inline & arch function */
@@ -35,9 +41,6 @@
 
 /* Prototypes for non-inlined arch strings functions. */
 int memcmp(const void *s1, const void *s2, size_t n);
-void *memcpy(void *dest, const void *src, size_t n);
-void *memset(void *s, int c, size_t n);
-void *memmove(void *dest, const void *src, size_t n);
 int strcmp(const char *s1, const char *s2);
 size_t strlcat(char *dest, const char *src, size_t n);
 size_t strlcpy(char *dest, const char *src, size_t size);
@@ -45,6 +48,7 @@ char *strncat(char *dest, const char *src, size_t n);
 char *strncpy(char *dest, const char *src, size_t n);
 char *strrchr(const char *s, int c);
 char *strstr(const char *s1, const char *s2);
+#endif /* !CONFIG_KASAN */
 
 #undef __HAVE_ARCH_STRCHR
 #undef __HAVE_ARCH_STRNCHR
@@ -95,6 +99,7 @@ static inline void *memset64(uint64_t *s, uint64_t v, size_t count)
 
 #if !defined(IN_ARCH_STRING_C) && (!defined(CONFIG_FORTIFY_SOURCE) || defined(__NO_FORTIFY))
 
+#ifdef __HAVE_ARCH_MEMCHR
 static inline void *memchr(const void * s, int c, size_t n)
 {
 	register int r0 asm("0") = (char) c;
@@ -109,7 +114,9 @@ static inline void *memchr(const void * s, int c, size_t n)
 		: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
 	return (void *) ret;
 }
+#endif
 
+#ifdef __HAVE_ARCH_MEMSCAN
 static inline void *memscan(void *s, int c, size_t n)
 {
 	register int r0 asm("0") = (char) c;
@@ -121,7 +128,9 @@ static inline void *memscan(void *s, int c, size_t n)
 		: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
 	return (void *) ret;
 }
+#endif
 
+#ifdef __HAVE_ARCH_STRCAT
 static inline char *strcat(char *dst, const char *src)
 {
 	register int r0 asm("0") = 0;
@@ -137,7 +146,9 @@ static inline char *strcat(char *dst, const char *src)
 		: "d" (r0), "0" (0) : "cc", "memory" );
 	return ret;
 }
+#endif
 
+#ifdef __HAVE_ARCH_STRCPY
 static inline char *strcpy(char *dst, const char *src)
 {
 	register int r0 asm("0") = 0;
@@ -150,7 +161,9 @@ static inline char *strcpy(char *dst, const char *src)
 		: "cc", "memory");
 	return ret;
 }
+#endif
 
+#ifdef __HAVE_ARCH_STRLEN
 static inline size_t strlen(const char *s)
 {
 	register unsigned long r0 asm("0") = 0;
@@ -162,7 +175,9 @@ static inline size_t strlen(const char *s)
 		: "+d" (r0), "+a" (tmp) :  : "cc", "memory");
 	return r0 - (unsigned long) s;
 }
+#endif
 
+#ifdef __HAVE_ARCH_STRNLEN
 static inline size_t strnlen(const char * s, size_t n)
 {
 	register int r0 asm("0") = 0;
@@ -175,6 +190,7 @@ static inline size_t strnlen(const char * s, size_t n)
 		: "+a" (end), "+a" (tmp) : "d" (r0)  : "cc", "memory");
 	return end - s;
 }
+#endif
 #else /* IN_ARCH_STRING_C */
 void *memchr(const void * s, int c, size_t n);
 void *memscan(void *s, int c, size_t n);

arch/s390/lib/string.c

@@ -43,11 +43,13 @@ static inline char *__strnend(const char *s, size_t n)
  *
  * returns the length of @s
  */
+#ifdef __HAVE_ARCH_STRLEN
 size_t strlen(const char *s)
 {
 	return __strend(s) - s;
 }
 EXPORT_SYMBOL(strlen);
+#endif
 
 /**
  * strnlen - Find the length of a length-limited string
@@ -56,11 +58,13 @@ EXPORT_SYMBOL(strlen);
  *
  * returns the minimum of the length of @s and @n
  */
+#ifdef __HAVE_ARCH_STRNLEN
 size_t strnlen(const char *s, size_t n)
 {
 	return __strnend(s, n) - s;
 }
 EXPORT_SYMBOL(strnlen);
+#endif
 
 /**
  * strcpy - Copy a %NUL terminated string
@@ -69,6 +73,7 @@ EXPORT_SYMBOL(strnlen);
  *
  * returns a pointer to @dest
  */
+#ifdef __HAVE_ARCH_STRCPY
 char *strcpy(char *dest, const char *src)
 {
 	register int r0 asm("0") = 0;
@@ -81,6 +86,7 @@ char *strcpy(char *dest, const char *src)
 	return ret;
 }
 EXPORT_SYMBOL(strcpy);
+#endif
 
 /**
  * strlcpy - Copy a %NUL terminated string into a sized buffer
@@ -93,6 +99,7 @@ EXPORT_SYMBOL(strcpy);
  * of course, the buffer size is zero). It does not pad
  * out the result like strncpy() does.
  */
+#ifdef __HAVE_ARCH_STRLCPY
 size_t strlcpy(char *dest, const char *src, size_t size)
 {
 	size_t ret = __strend(src) - src;
@@ -105,6 +112,7 @@ size_t strlcpy(char *dest, const char *src, size_t size)
 	return ret;
 }
 EXPORT_SYMBOL(strlcpy);
+#endif
 
 /**
  * strncpy - Copy a length-limited, %NUL-terminated string
@@ -115,6 +123,7 @@ EXPORT_SYMBOL(strlcpy);
  * The result is not %NUL-terminated if the source exceeds
  * @n bytes.
  */
+#ifdef __HAVE_ARCH_STRNCPY
 char *strncpy(char *dest, const char *src, size_t n)
 {
 	size_t len = __strnend(src, n) - src;
@@ -123,6 +132,7 @@ char *strncpy(char *dest, const char *src, size_t n)
 	return dest;
 }
 EXPORT_SYMBOL(strncpy);
+#endif
 
 /**
  * strcat - Append one %NUL-terminated string to another
@@ -131,6 +141,7 @@ EXPORT_SYMBOL(strncpy);
  *
  * returns a pointer to @dest
  */
+#ifdef __HAVE_ARCH_STRCAT
 char *strcat(char *dest, const char *src)
 {
 	register int r0 asm("0") = 0;
@@ -146,6 +157,7 @@ char *strcat(char *dest, const char *src)
 	return ret;
 }
 EXPORT_SYMBOL(strcat);
+#endif
 
 /**
  * strlcat - Append a length-limited, %NUL-terminated string to another
@@ -153,6 +165,7 @@ EXPORT_SYMBOL(strcat);
  * @src: The string to append to it
  * @n: The size of the destination buffer.
  */
+#ifdef __HAVE_ARCH_STRLCAT
 size_t strlcat(char *dest, const char *src, size_t n)
 {
 	size_t dsize = __strend(dest) - dest;
@@ -170,6 +183,7 @@ size_t strlcat(char *dest, const char *src, size_t n)
 	return res;
 }
 EXPORT_SYMBOL(strlcat);
+#endif
 
 /**
  * strncat - Append a length-limited, %NUL-terminated string to another
@@ -182,6 +196,7 @@ EXPORT_SYMBOL(strlcat);
  * Note that in contrast to strncpy, strncat ensures the result is
  * terminated.
  */
+#ifdef __HAVE_ARCH_STRNCAT
 char *strncat(char *dest, const char *src, size_t n)
 {
 	size_t len = __strnend(src, n) - src;
@@ -192,6 +207,7 @@ char *strncat(char *dest, const char *src, size_t n)
 	return dest;
 }
 EXPORT_SYMBOL(strncat);
+#endif
 
 /**
  * strcmp - Compare two strings
@@ -202,6 +218,7 @@ EXPORT_SYMBOL(strncat);
  *	   < 0 if @s1 is less than @s2
  *	   > 0 if @s1 is greater than @s2
  */
+#ifdef __HAVE_ARCH_STRCMP
 int strcmp(const char *s1, const char *s2)
 {
 	register int r0 asm("0") = 0;
@@ -219,12 +236,14 @@ int strcmp(const char *s1, const char *s2)
 	return ret;
 }
 EXPORT_SYMBOL(strcmp);
+#endif
 
 /**
  * strrchr - Find the last occurrence of a character in a string
  * @s: The string to be searched
  * @c: The character to search for
  */
+#ifdef __HAVE_ARCH_STRRCHR
 char *strrchr(const char *s, int c)
 {
        size_t len = __strend(s) - s;
@@ -237,6 +256,7 @@ char *strrchr(const char *s, int c)
        return NULL;
 }
 EXPORT_SYMBOL(strrchr);
+#endif
 
 static inline int clcle(const char *s1, unsigned long l1,
 			const char *s2, unsigned long l2)
@@ -261,6 +281,7 @@ static inline int clcle(const char *s1, unsigned long l1,
  * @s1: The string to be searched
  * @s2: The string to search for
  */
+#ifdef __HAVE_ARCH_STRSTR
 char *strstr(const char *s1, const char *s2)
 {
 	int l1, l2;
@@ -280,6 +301,7 @@ char *strstr(const char *s1, const char *s2)
 	return NULL;
 }
 EXPORT_SYMBOL(strstr);
+#endif
 
 /**
  * memchr - Find a character in an area of memory.
@@ -290,6 +312,7 @@ EXPORT_SYMBOL(strstr);
  * returns the address of the first occurrence of @c, or %NULL
  * if @c is not found
  */
+#ifdef __HAVE_ARCH_MEMCHR
 void *memchr(const void *s, int c, size_t n)
 {
 	register int r0 asm("0") = (char) c;
@@ -304,6 +327,7 @@ void *memchr(const void *s, int c, size_t n)
 	return (void *) ret;
 }
 EXPORT_SYMBOL(memchr);
+#endif
 
 /**
  * memcmp - Compare two areas of memory
@@ -311,6 +335,7 @@ EXPORT_SYMBOL(memchr);
  * @s2: Another area of memory
  * @count: The size of the area.
  */
+#ifdef __HAVE_ARCH_MEMCMP
 int memcmp(const void *s1, const void *s2, size_t n)
 {
 	int ret;
@@ -321,6 +346,7 @@ int memcmp(const void *s1, const void *s2, size_t n)
 	return ret;
 }
 EXPORT_SYMBOL(memcmp);
+#endif
 
 /**
  * memscan - Find a character in an area of memory.
@@ -331,6 +357,7 @@ EXPORT_SYMBOL(memcmp);
  * returns the address of the first occurrence of @c, or 1 byte past
  * the area if @c is not found
  */
+#ifdef __HAVE_ARCH_MEMSCAN
 void *memscan(void *s, int c, size_t n)
 {
 	register int r0 asm("0") = (char) c;
@@ -342,3 +369,4 @@ void *memscan(void *s, int c, size_t n)
 	return (void *) ret;
 }
 EXPORT_SYMBOL(memscan);
+#endif