On 2018-09-05 오전 1:24, Andrey Ryabinin wrote:
On 09/04/2018 01:10 PM, Andrey Ryabinin wrote:
>
>
> On 09/04/2018 09:59 AM, Kyeongdon Kim wrote:
>
>>>> +#undef strncmp
>>>> +int strncmp(const char *cs, const char *ct, size_t len)
>>>> +{
>>>> + check_memory_region((unsigned long)cs, len, false, _RET_IP_);
>>>> + check_memory_region((unsigned long)ct, len, false, _RET_IP_);
>>>
>>> This will cause false positives. Both 'cs', and 'ct' could be less
than len bytes.
>>>
>>> There is no need in these interceptors, just use the C
implementations from lib/string.c
>>> like you did in your first patch.
>>> The only thing that was wrong in the first patch is that assembly
implementations
>>> were compiled out instead of being declared week.
>>>
>> Well, at first I thought so..
>> I would remove diff code in /mm/kasan/kasan.c then use C
implementations in lib/string.c
>> w/ assem implementations as weak :
>>
>> diff --git a/lib/string.c b/lib/string.c
>> index 2c0900a..a18b18f 100644
>> --- a/lib/string.c
>> +++ b/lib/string.c
>> @@ -312,7 +312,7 @@ size_t strlcat(char *dest, const char *src,
size_t count)
>> EXPORT_SYMBOL(strlcat);
>> #endif
>>
>> -#ifndef __HAVE_ARCH_STRCMP
>> +#if (defined(CONFIG_ARM64) && defined(CONFIG_KASAN)) ||
!defined(__HAVE_ARCH_STRCMP)
>
> No. What part of "like you did in your first patch" is unclear to you?
Just to be absolutely clear, I meant #ifdef out __HAVE_ARCH_* defines
like it has been done in this patch
http://lkml.kernel.org/r/<1534233322-106271-1-git-send-email-kyeongdon.kim@xxxxxxx>
I understood what you're saying, but I might think the wrong patch.
So, thinking about the other way as below:
can pick up assem variant or c one, declare them as weak.
---
diff --git a/arch/arm64/include/asm/string.h
b/arch/arm64/include/asm/string.h
index dd95d33..53a2ae0 100644
--- a/arch/arm64/include/asm/string.h
+++ b/arch/arm64/include/asm/string.h
@@ -22,11 +22,22 @@ extern char *strrchr(const char *, int c);
#define __HAVE_ARCH_STRCHR
extern char *strchr(const char *, int c);
+#ifdef CONFIG_KASAN
+extern int __strcmp(const char *, const char *);
+extern int __strncmp(const char *, const char *, __kernel_size_t);
+
+#ifndef __SANITIZE_ADDRESS__
+#define strcmp(cs, ct) __strcmp(cs, ct)
+#define strncmp(cs, ct, n) __strncmp(cs, ct, n)
+#endif
+
+#else
#define __HAVE_ARCH_STRCMP
extern int strcmp(const char *, const char *);
#define __HAVE_ARCH_STRNCMP
extern int strncmp(const char *, const char *, __kernel_size_t);
+#endif
#define __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c
index d894a20..9aeffd5 100644
--- a/arch/arm64/kernel/arm64ksyms.c
+++ b/arch/arm64/kernel/arm64ksyms.c
@@ -50,6 +50,10 @@ EXPORT_SYMBOL(strcmp);
EXPORT_SYMBOL(strncmp);
EXPORT_SYMBOL(strlen);
EXPORT_SYMBOL(strnlen);
+#ifdef CONFIG_KASAN
+EXPORT_SYMBOL(__strcmp);
+EXPORT_SYMBOL(__strncmp);
+#endif
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memmove);
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index a820ed0..5ef7a57 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -110,6 +110,8 @@ __efistub___flush_dcache_area =
KALLSYMS_HIDE(__pi___flush_dcache_area);
__efistub___memcpy = KALLSYMS_HIDE(__pi_memcpy);
__efistub___memmove = KALLSYMS_HIDE(__pi_memmove);
__efistub___memset = KALLSYMS_HIDE(__pi_memset);
+__efistub___strcmp = KALLSYMS_HIDE(__pi_strcmp);
+__efistub___strncmp = KALLSYMS_HIDE(__pi_strncmp);
#endif
__efistub__text = KALLSYMS_HIDE(_text);
diff --git a/arch/arm64/lib/strcmp.S b/arch/arm64/lib/strcmp.S
index 471fe61..0dffef7 100644
--- a/arch/arm64/lib/strcmp.S
+++ b/arch/arm64/lib/strcmp.S
@@ -60,6 +60,8 @@ tmp3 .req x9
zeroones .req x10
pos .req x11
+.weak strcmp
+ENTRY(__strcmp)
ENTRY(strcmp)
eor tmp1, src1, src2
mov zeroones, #REP8_01
@@ -232,3 +234,4 @@ CPU_BE( orr syndrome, diff, has_nul )
sub result, data1, data2, lsr #56
ret
ENDPIPROC(strcmp)
+ENDPROC(__strcmp)
diff --git a/arch/arm64/lib/strncmp.S b/arch/arm64/lib/strncmp.S
index e267044..b2648c7 100644
--- a/arch/arm64/lib/strncmp.S
+++ b/arch/arm64/lib/strncmp.S
@@ -64,6 +64,8 @@ limit_wd .req x13
mask .req x14
endloop .req x15
+.weak strncmp
+ENTRY(__strncmp)
ENTRY(strncmp)
cbz limit, .Lret0
eor tmp1, src1, src2
@@ -308,3 +310,4 @@ CPU_BE( orr syndrome, diff, has_nul )
mov result, #0
ret
ENDPIPROC(strncmp)
+ENDPROC(__strncmp)
--
Could you review this diff?
