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Commit f45f7b5b authored by Vasily Gorbik's avatar Vasily Gorbik
Browse files

s390/kasan: provide uninstrumented __strlen 



s390 kasan code uses sclp_early_printk to report initialization
failures. The code doing that should not be instrumented, because kasan
shadow memory has not been set up yet. Even though sclp_early_core.c is
compiled with instrumentation disabled it uses strlen function, which
is instrumented and would produce shadow memory access if used. To
avoid that, introduce uninstrumented __strlen function to be used
instead.

Before commit 7e0d92f0 ("s390/kasan: improve string/memory functions
checks") few string functions (including strlen) were escaping kasan
instrumentation due to usage of platform specific versions which are
implemented in inline assembly.

Fixes: 7e0d92f0 ("s390/kasan: improve string/memory functions checks")
Acked-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 2e83e0eb

arch/s390/include/asm/string.h

+7 −2
Original line number Diff line number Diff line
@@ -71,11 +71,16 @@ extern void *__memmove(void *dest, const void *src, size_t n); 
#define memcpy(dst, src, len) __memcpy(dst, src, len)

#define memmove(dst, src, len) __memmove(dst, src, len)

#define memset(s, c, n) __memset(s, c, n)

#define strlen(s) __strlen(s)



#define __no_sanitize_prefix_strfunc(x) __##x



#ifndef __NO_FORTIFY

#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */

#endif



#else

#define __no_sanitize_prefix_strfunc(x) x

#endif /* defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) */



void *__memset16(uint16_t *s, uint16_t v, size_t count);
@@ -163,8 +168,8 @@ static inline char *strcpy(char *dst, const char *src) 
}

#endif



#ifdef __HAVE_ARCH_STRLEN

static inline size_t strlen(const char *s)

#if defined(__HAVE_ARCH_STRLEN) || (defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__))

static inline size_t __no_sanitize_prefix_strfunc(strlen)(const char *s)

{

	register unsigned long r0 asm("0") = 0;

	const char *tmp = s;