From: Andrey Ryabinin <[email protected]> Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly.
KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Cc: Andrey Ryabinin <[email protected]> Signed-off-by: Abbott Liu <[email protected]> --- arch/arm/include/asm/string.h | 18 +++++++++++++++++- arch/arm/lib/memcpy.S | 3 +++ arch/arm/lib/memmove.S | 5 ++++- arch/arm/lib/memset.S | 3 +++ 4 files changed, 27 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/string.h b/arch/arm/include/asm/string.h index fe1c6af..43325f8 100644 --- a/arch/arm/include/asm/string.h +++ b/arch/arm/include/asm/string.h @@ -14,15 +14,18 @@ extern char * strchr(const char * s, int c); #define __HAVE_ARCH_MEMCPY extern void * memcpy(void *, const void *, __kernel_size_t); +extern void * __memcpy(void *, const void *, __kernel_size_t); #define __HAVE_ARCH_MEMMOVE 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_MEMSET32 extern void *__memset32(uint32_t *, uint32_t v, __kernel_size_t); @@ -39,7 +42,7 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n) } extern void __memzero(void *ptr, __kernel_size_t n); - +#ifndef CONFIG_KASAN #define memset(p,v,n) \ ({ \ void *__p = (p); size_t __n = n; \ @@ -51,5 +54,18 @@ extern void __memzero(void *ptr, __kernel_size_t n); } \ (__p); \ }) +#endif + +#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. + */ + +#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 diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S index 64111bd..79a83f8 100644 --- a/arch/arm/lib/memcpy.S +++ b/arch/arm/lib/memcpy.S @@ -61,6 +61,8 @@ /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */ +.weak memcpy +ENTRY(__memcpy) ENTRY(mmiocpy) ENTRY(memcpy) @@ -68,3 +70,4 @@ ENTRY(memcpy) ENDPROC(memcpy) ENDPROC(mmiocpy) +ENDPROC(__memcpy) diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S index 69a9d47..313db6c 100644 --- a/arch/arm/lib/memmove.S +++ b/arch/arm/lib/memmove.S @@ -27,12 +27,14 @@ * occurring in the opposite direction. */ +.weak memmove +ENTRY(__memmove) ENTRY(memmove) UNWIND( .fnstart ) subs ip, r0, r1 cmphi r2, ip - bls memcpy + bls __memcpy stmfd sp!, {r0, r4, lr} UNWIND( .fnend ) @@ -225,3 +227,4 @@ ENTRY(memmove) 18: backward_copy_shift push=24 pull=8 ENDPROC(memmove) +ENDPROC(__memmove) diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index ed6d35d..64aa06a 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -16,6 +16,8 @@ .text .align 5 +.weak memset +ENTRY(__memset) ENTRY(mmioset) ENTRY(memset) UNWIND( .fnstart ) @@ -135,6 +137,7 @@ UNWIND( .fnstart ) UNWIND( .fnend ) ENDPROC(memset) ENDPROC(mmioset) +ENDPROC(__memset) ENTRY(__memset32) UNWIND( .fnstart ) -- 2.9.0
