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Commit 99b2e2c1 authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Alistair Delva
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UPSTREAM: arm64: lib: use C string functions with KASAN enabled 

(Upstream commit 19a2ca0fb560fd7be7b5293c6b652c6d6078dcde).

ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len().  KASAN don't see memory accesses in asm code,
thus it can potentially miss many bugs.

Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled,
so the generic implementations from lib/string.c will be used.

We can't just remove the asm functions because efistub uses them.  And we
can't have two non-weak functions either, so declare the asm functions as
weak.

Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com


Signed-off-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: default avatarKyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Bug: 128674696
Change-Id: If91aebb7d79172e5a712a5830414aada04dce4b7
parent e18e6f7e

arch/arm64/include/asm/string.h

+8 −6
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#ifndef __ASM_STRING_H

#define __ASM_STRING_H



#ifndef CONFIG_KASAN

#define __HAVE_ARCH_STRRCHR

extern char *strrchr(const char *, int c);
@@ -34,6 +35,13 @@ extern __kernel_size_t strlen(const char *); 
#define __HAVE_ARCH_STRNLEN

extern __kernel_size_t strnlen(const char *, __kernel_size_t);



#define __HAVE_ARCH_MEMCMP

extern int memcmp(const void *, const void *, size_t);



#define __HAVE_ARCH_MEMCHR

extern void *memchr(const void *, int, __kernel_size_t);

#endif



#define __HAVE_ARCH_MEMCPY

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

extern void *__memcpy(void *, const void *, __kernel_size_t);
@@ -42,16 +50,10 @@ extern void *__memcpy(void *, const void *, __kernel_size_t); 
extern void *memmove(void *, const void *, __kernel_size_t);

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



#define __HAVE_ARCH_MEMCHR

extern void *memchr(const void *, int, __kernel_size_t);



#define __HAVE_ARCH_MEMSET

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

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



#define __HAVE_ARCH_MEMCMP

extern int memcmp(const void *, const void *, size_t);



#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE

#define __HAVE_ARCH_MEMCPY_FLUSHCACHE

void memcpy_flushcache(void *dst, const void *src, size_t cnt);

arch/arm64/kernel/arm64ksyms.c

+5 −2
Original line number Diff line number Diff line
@@ -44,20 +44,23 @@ EXPORT_SYMBOL(__arch_copy_in_user); 
EXPORT_SYMBOL(memstart_addr);



	/* string / mem functions */

#ifndef CONFIG_KASAN

EXPORT_SYMBOL(strchr);

EXPORT_SYMBOL(strrchr);

EXPORT_SYMBOL(strcmp);

EXPORT_SYMBOL(strncmp);

EXPORT_SYMBOL(strlen);

EXPORT_SYMBOL(strnlen);

EXPORT_SYMBOL(memcmp);

EXPORT_SYMBOL(memchr);

#endif



EXPORT_SYMBOL(memset);

EXPORT_SYMBOL(memcpy);

EXPORT_SYMBOL(memmove);

EXPORT_SYMBOL(__memset);

EXPORT_SYMBOL(__memcpy);

EXPORT_SYMBOL(__memmove);

EXPORT_SYMBOL(memchr);

EXPORT_SYMBOL(memcmp);



	/* atomic bitops */

EXPORT_SYMBOL(set_bit);

arch/arm64/lib/memchr.S

+1 −1
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ 
 * Returns:

 *	x0 - address of first occurrence of 'c' or 0

 */

ENTRY(memchr)

WEAK(memchr)

	and	w1, w1, #0xff

1:	subs	x2, x2, #1

	b.mi	2f

arch/arm64/lib/memcmp.S

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ pos .req x11 
limit_wd	.req	x12

mask		.req	x13



ENTRY(memcmp)

WEAK(memcmp)

	cbz	limit, .Lret0

	eor	tmp1, src1, src2

	tst	tmp1, #7

arch/arm64/lib/strchr.S

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ 
 * Returns:

 *	x0 - address of first occurrence of 'c' or 0

 */

ENTRY(strchr)

WEAK(strchr)

	and	w1, w1, #0xff

1:	ldrb	w2, [x0], #1

	cmp	w2, w1