From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by kanga.kvack.org (Postfix) with ESMTP id 5AD3A6B71E2 for ; Wed, 5 Sep 2018 03:45:01 -0400 (EDT) Received: by mail-pg1-f200.google.com with SMTP id d132-v6so3187164pgc.22 for ; Wed, 05 Sep 2018 00:45:01 -0700 (PDT) Received: from lgeamrelo11.lge.com (lgeamrelo11.lge.com. [156.147.23.51]) by mx.google.com with ESMTP id 97-v6si1251115plm.290.2018.09.05.00.44.59 for ; Wed, 05 Sep 2018 00:44:59 -0700 (PDT) Subject: Re: Re: [PATCH v2] arm64: kasan: add interceptors for strcmp/strncmp functions References: <1535014606-176525-1-git-send-email-kyeongdon.kim@lge.com> <12d4e435-e229-b4af-4286-a53fa77cb09d@virtuozzo.com> From: Kyeongdon Kim Message-ID: <0bde837e-2804-c6d6-4bda-8b166bdcfc6b@lge.com> Date: Wed, 5 Sep 2018 16:44:54 +0900 MIME-Version: 1.0 In-Reply-To: <12d4e435-e229-b4af-4286-a53fa77cb09d@virtuozzo.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Ryabinin Cc: catalin.marinas@arm.com, will.deacon@arm.com, glider@google.com, dvyukov@google.com, Jason@zx2c4.com, robh@kernel.org, ard.biesheuvel@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org On 2018-09-05 i??i ? 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) > >> A EXPORT_SYMBOL(strlcat); > >> A #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@lge.com> > 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); A #define __HAVE_ARCH_STRCHR A 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 A #define __HAVE_ARCH_STRCMP A extern int strcmp(const char *, const char *); A #define __HAVE_ARCH_STRNCMP A extern int strncmp(const char *, const char *, __kernel_size_t); +#endif A #define __HAVE_ARCH_STRLEN A 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); A EXPORT_SYMBOL(strncmp); A EXPORT_SYMBOL(strlen); A EXPORT_SYMBOL(strnlen); +#ifdef CONFIG_KASAN +EXPORT_SYMBOL(__strcmp); +EXPORT_SYMBOL(__strncmp); +#endif A EXPORT_SYMBOL(memset); A EXPORT_SYMBOL(memcpy); A 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_areaA A A = KALLSYMS_HIDE(__pi___flush_dcache_area); A __efistub___memcpyA A A A A A = KALLSYMS_HIDE(__pi_memcpy); A __efistub___memmoveA A A A A A = KALLSYMS_HIDE(__pi_memmove); A __efistub___memsetA A A A A A = KALLSYMS_HIDE(__pi_memset); +__efistub___strcmpA A A A A A = KALLSYMS_HIDE(__pi_strcmp); +__efistub___strncmpA A A A A A = KALLSYMS_HIDE(__pi_strncmp); A #endif A __efistub__textA A A A A A A A A = 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 @@ tmp3A A A A A A .reqA A A x9 A zeroonesA A A .reqA A A x10 A posA A A A A A .reqA A A x11 +.weak strcmp +ENTRY(__strcmp) A ENTRY(strcmp) A A A A eorA A A tmp1, src1, src2 A A A A movA A A zeroones, #REP8_01 @@ -232,3 +234,4 @@ CPU_BE(A A A orrA A A syndrome, diff, has_nul ) A A A A subA A A result, data1, data2, lsr #56 A A A A ret A 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_wdA A A .reqA A A x13 A maskA A A A A A .reqA A A x14 A endloopA A A A A A .reqA A A x15 +.weak strncmp +ENTRY(__strncmp) A ENTRY(strncmp) A A A A cbzA A A limit, .Lret0 A A A A eorA A A tmp1, src1, src2 @@ -308,3 +310,4 @@ CPU_BE( orrA A A syndrome, diff, has_nul ) A A A A movA A A result, #0 A A A A ret A ENDPIPROC(strncmp) +ENDPROC(__strncmp) -- Could you review this diff?