From: Andrey Ryabinin <aryabi...@virtuozzo.com>
Functions like memset/memmove/memcpy do a lot of memory accesses. If a
bad pointer pis assed to one of these function it is important to catch
this. Compiler 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.
We must use __memcpy/__memset to replace memcpy/memset when we copy
.data to RAM and when we clear .bss, because kasan_early_init cannot be
called before the initialization of .data and .bss.
Reported-by: Russell King - ARM Linux <li...@armlinux.org.uk>
Tested-by: Linus Walleij <linus.wall...@linaro.org>
Signed-off-by: Abbott Liu <liuwenli...@huawei.com>
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
---
arch/arm/include/asm/string.h | 17 +++++++++++++++++
arch/arm/kernel/head-common.S | 4 ++--
arch/arm/lib/memcpy.S | 3 +++
arch/arm/lib/memmove.S | 5 ++++-
arch/arm/lib/memset.S | 3 +++
5 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/string.h b/arch/arm/include/asm/string.h
index 111a1d8a41dd..1f9016bbf153 100644
--- a/arch/arm/include/asm/string.h
+++ b/arch/arm/include/asm/string.h
@@ -15,15 +15,18 @@ 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 *dest, const void *src, __kernel_size_t n);
#define __HAVE_ARCH_MEMMOVE
extern void * memmove(void *, const void *, __kernel_size_t);
+extern void *__memmove(void *dest, const void *src, __kernel_size_t n);
#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 *s, int c, __kernel_size_t n);
#define __HAVE_ARCH_MEMSET32
extern void *__memset32(uint32_t *, uint32_t v, __kernel_size_t);
@@ -39,4 +42,18 @@ static inline void *memset64(uint64_t *p, uint64_t v,
__kernel_size_t n)
return __memset64(p, v, n * 8, v >> 32);
}
+
+
+#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/kernel/head-common.S b/arch/arm/kernel/head-common.S
index 4a3982812a40..6840c7c60a85 100644
--- a/arch/arm/kernel/head-common.S
+++ b/arch/arm/kernel/head-common.S
@@ -95,7 +95,7 @@ __mmap_switched:
THUMB( ldmia r4!, {r0, r1, r2, r3} )
THUMB( mov sp, r3 )
sub r2, r2, r1
- bl memcpy @ copy .data to RAM
+ bl __memcpy @ copy .data to RAM
#endif
ARM( ldmia r4!, {r0, r1, sp} )
@@ -103,7 +103,7 @@ __mmap_switched:
THUMB( mov sp, r3 )
sub r2, r1, r0
mov r1, #0
- bl memset @ clear .bss
+ bl __memset @ clear .bss
ldmia r4, {r0, r1, r2, r3}
str r9, [r0] @ Save processor ID
diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S
index 09a333153dc6..ad4625d16e11 100644
--- a/arch/arm/lib/memcpy.S
+++ b/arch/arm/lib/memcpy.S
@@ -58,6 +58,8 @@
/* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
+.weak memcpy
+ENTRY(__memcpy)
ENTRY(mmiocpy)
ENTRY(memcpy)
@@ -65,3 +67,4 @@ ENTRY(memcpy)
ENDPROC(memcpy)
ENDPROC(mmiocpy)
+ENDPROC(__memcpy)
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S
index b50e5770fb44..fd123ea5a5a4 100644
--- a/arch/arm/lib/memmove.S
+++ b/arch/arm/lib/memmove.S
@@ -24,12 +24,14 @@
* 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 )
@@ -222,3 +224,4 @@ 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 6ca4535c47fb..0e7ff0423f50 100644
--- a/arch/arm/lib/memset.S
+++ b/arch/arm/lib/memset.S
@@ -13,6 +13,8 @@
.text
.align 5
+.weak memset
+ENTRY(__memset)
ENTRY(mmioset)
ENTRY(memset)
UNWIND( .fnstart )
@@ -132,6 +134,7 @@ UNWIND( .fnstart )
UNWIND( .fnend )
ENDPROC(memset)
ENDPROC(mmioset)
+ENDPROC(__memset)
ENTRY(__memset32)
UNWIND( .fnstart )
--
2.17.1
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