Commit 393f203f authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Linus Torvalds
Browse files

x86_64: kasan: add interceptors for memset/memmove/memcpy functions 



Recently instrumentation of builtin functions calls was removed from GCC
5.0.  To check the memory accessed by such functions, userspace asan
always uses interceptors for them.

So now we should do this as well.  This patch declares
memset/memmove/memcpy as weak symbols.  In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.

Default memset/memmove/memcpy now now always have aliases with '__'
prefix.  For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.

Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3f15801c

arch/x86/boot/compressed/eboot.c

+1 −2
Original line number Diff line number Diff line
@@ -13,8 +13,7 @@ 
#include <asm/setup.h>

#include <asm/desc.h>



#undef memcpy			/* Use memcpy from misc.c */



#include "../string.h"

#include "eboot.h"



static efi_system_table_t *sys_table;

arch/x86/boot/compressed/misc.h

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 * we just keep it from happening

 */

#undef CONFIG_PARAVIRT

#undef CONFIG_KASAN

#ifdef CONFIG_X86_32

#define _ASM_X86_DESC_H 1

#endif

arch/x86/include/asm/string_64.h

+17 −1
Original line number Diff line number Diff line
@@ -27,11 +27,12 @@ static __always_inline void *__inline_memcpy(void *to, const void *from, size_t 
   function. */



#define __HAVE_ARCH_MEMCPY 1

extern void *__memcpy(void *to, const void *from, size_t len);



#ifndef CONFIG_KMEMCHECK

#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4

extern void *memcpy(void *to, const void *from, size_t len);

#else

extern void *__memcpy(void *to, const void *from, size_t len);

#define memcpy(dst, src, len)					\

({								\

	size_t __len = (len);					\
@@ -53,9 +54,11 @@ extern void *__memcpy(void *to, const void *from, size_t len); 


#define __HAVE_ARCH_MEMSET

void *memset(void *s, int c, size_t n);

void *__memset(void *s, int c, size_t n);



#define __HAVE_ARCH_MEMMOVE

void *memmove(void *dest, const void *src, size_t count);

void *__memmove(void *dest, const void *src, size_t count);



int memcmp(const void *cs, const void *ct, size_t count);

size_t strlen(const char *s);
@@ -63,6 +66,19 @@ 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__)



/*

 * For files that not instrumented (e.g. mm/slub.c) we

 * should use not instrumented version of mem* functions.

 */



#undef memcpy

#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)

#endif



#endif /* __KERNEL__ */



#endif /* _ASM_X86_STRING_64_H */

arch/x86/kernel/x8664_ksyms_64.c

+8 −2
Original line number Diff line number Diff line
@@ -50,13 +50,19 @@ EXPORT_SYMBOL(csum_partial); 
#undef memset

#undef memmove



extern void *__memset(void *, int, __kernel_size_t);

extern void *__memcpy(void *, const void *, __kernel_size_t);

extern void *__memmove(void *, const void *, __kernel_size_t);

extern void *memset(void *, int, __kernel_size_t);

extern void *memcpy(void *, const void *, __kernel_size_t);

extern void *__memcpy(void *, const void *, __kernel_size_t);

extern void *memmove(void *, const void *, __kernel_size_t);



EXPORT_SYMBOL(__memset);

EXPORT_SYMBOL(__memcpy);

EXPORT_SYMBOL(__memmove);



EXPORT_SYMBOL(memset);

EXPORT_SYMBOL(memcpy);

EXPORT_SYMBOL(__memcpy);

EXPORT_SYMBOL(memmove);



#ifndef CONFIG_DEBUG_VIRTUAL

arch/x86/lib/memcpy_64.S

+4 −2
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ 
.Lmemcpy_e_e:

	.previous



.weak memcpy



ENTRY(__memcpy)

ENTRY(memcpy)

	CFI_STARTPROC
@@ -199,8 +201,8 @@ ENDPROC(__memcpy) 
	 * only outcome...

	 */

	.section .altinstructions, "a"

	altinstruction_entry memcpy,.Lmemcpy_c,X86_FEATURE_REP_GOOD,\

	altinstruction_entry __memcpy,.Lmemcpy_c,X86_FEATURE_REP_GOOD,\

			     .Lmemcpy_e-.Lmemcpy_c,.Lmemcpy_e-.Lmemcpy_c

	altinstruction_entry memcpy,.Lmemcpy_c_e,X86_FEATURE_ERMS, \

	altinstruction_entry __memcpy,.Lmemcpy_c_e,X86_FEATURE_ERMS, \

			     .Lmemcpy_e_e-.Lmemcpy_c_e,.Lmemcpy_e_e-.Lmemcpy_c_e

	.previous

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