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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: Sascha Hauer <s.hauer@pengutronix.de>,
	Barebox List <barebox@lists.infradead.org>
Subject: Re: [PATCH 9/9] ARM: Add KASan support
Date: Tue, 9 Feb 2021 10:25:57 +0100	[thread overview]
Message-ID: <c513bdd8-dda7-956d-b237-5f960878fa02@pengutronix.de> (raw)
In-Reply-To: <20200918084532.2794-10-s.hauer@pengutronix.de>

Hello Sascha,

On 18.09.20 10:45, Sascha Hauer wrote:
> This adds KASan support to the ARM architecture. What we are doing is:
> 
> * Add __no_sanitize_address attribute to various lowlevel functions
>   which do not run in a proper C environment
> * Add non-instrumented variants of memset/memcpy (prefixed with '__')
> * make original memcpy/memset weak symbols so strong definitions in
>   lib/kasan/common.c can replace them
> * Use non-instrumented memcpy in early functions
> * call kasan_init()
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  arch/arm/Kconfig              |  1 +
>  arch/arm/cpu/Makefile         |  2 ++
>  arch/arm/cpu/common.c         |  2 +-
>  arch/arm/cpu/setupc.S         |  6 +++---

Shouldn't you've touched setupc_64.S here as well?

>  arch/arm/cpu/start.c          |  7 +++++--
>  arch/arm/include/asm/string.h |  2 ++
>  arch/arm/lib32/barebox.lds.S  |  4 +++-
>  arch/arm/lib32/memcpy.S       |  3 +++
>  arch/arm/lib32/memset.S       |  4 +++-
>  arch/arm/lib64/string.c       | 26 +++++++++++++++++++++-----
>  10 files changed, 44 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 95fd8ecfe7..57ead9a783 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -4,6 +4,7 @@ config ARM
>  	select HAS_CACHE
>  	select HAVE_CONFIGURABLE_TEXT_BASE if !RELOCATABLE
>  	select HAVE_IMAGE_COMPRESSION
> +	select HAVE_ARCH_KASAN
>  	default y
>  
>  config ARM_LINUX
> diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
> index f7f9c30415..e7a6e3e6fb 100644
> --- a/arch/arm/cpu/Makefile
> +++ b/arch/arm/cpu/Makefile
> @@ -9,6 +9,7 @@ AFLAGS_hyp.o :=-Wa,-march=armv7-a -Wa,-mcpu=all
>  AFLAGS_hyp.pbl.o :=-Wa,-march=armv7-a -Wa,-mcpu=all
>  
>  obj-y += start.o entry.o entry_ll$(S64).o
> +KASAN_SANITIZE_start.o := n
>  
>  pbl-$(CONFIG_BOARD_ARM_GENERIC_DT) += board-dt-2nd.o
>  pbl-$(CONFIG_BOARD_ARM_GENERIC_DT_AARCH64) += board-dt-2nd-aarch64.o
> @@ -51,3 +52,4 @@ pbl-y += entry.o entry_ll$(S64).o
>  pbl-y += uncompress.o
>  
>  obj-pbl-y += common.o sections.o
> +KASAN_SANITIZE_common.o := n
> diff --git a/arch/arm/cpu/common.c b/arch/arm/cpu/common.c
> index 33f148fc0e..8cfcc8f6ce 100644
> --- a/arch/arm/cpu/common.c
> +++ b/arch/arm/cpu/common.c
> @@ -120,7 +120,7 @@ void relocate_to_current_adr(void)
>  		dstart += sizeof(*rel);
>  	}
>  
> -	memset(dynsym, 0, (unsigned long)dynend - (unsigned long)dynsym);
> +	__memset(dynsym, 0, (unsigned long)dynend - (unsigned long)dynsym);
>  #else
>  #error "Architecture not specified"
>  #endif
> diff --git a/arch/arm/cpu/setupc.S b/arch/arm/cpu/setupc.S
> index 8ae7c89a2c..55aa105b21 100644
> --- a/arch/arm/cpu/setupc.S
> +++ b/arch/arm/cpu/setupc.S
> @@ -21,12 +21,12 @@ ENTRY(setup_c)
>  	ldr	r2,=__bss_start
>  	sub	r2, r2, r0
>  	add	r1, r0, r4
> -	bl	memcpy			/* memcpy(_text, _text + offset, __bss_start - _text) */
> +	bl	__memcpy			/* memcpy(_text, _text + offset, __bss_start - _text) */
>  1:	ldr	r0, =__bss_start
>  	mov	r1, #0
>  	ldr	r2, =__bss_stop
>  	sub	r2, r2, r0
> -	bl	memset			/* clear bss */
> +	bl	__memset			/* clear bss */
>  	bl	sync_caches_for_execution
>  	sub	lr, r5, r4		/* adjust return address to new location */
>  	pop	{r4, r5}
> @@ -67,7 +67,7 @@ ENTRY(relocate_to_adr)
>  	sub	r7, r7, r1		/* sub address where we are actually running */
>  	add	r7, r7, r0		/* add address where we are going to run */
>  
> -	bl	memcpy			/* copy binary */
> +	bl	__memcpy			/* copy binary */
>  
>  	bl	sync_caches_for_execution
>  
> diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> index aeca459cb1..f48f5beea8 100644
> --- a/arch/arm/cpu/start.c
> +++ b/arch/arm/cpu/start.c
> @@ -15,6 +15,7 @@
>  #include <asm/unaligned.h>
>  #include <asm/cache.h>
>  #include <asm/mmu.h>
> +#include <linux/kasan.h>
>  #include <memory.h>
>  #include <uncompress.h>
>  #include <malloc.h>
> @@ -135,7 +136,7 @@ static int barebox_memory_areas_init(void)
>  }
>  device_initcall(barebox_memory_areas_init);
>  
> -__noreturn void barebox_non_pbl_start(unsigned long membase,
> +__noreturn __no_sanitize_address void barebox_non_pbl_start(unsigned long membase,
>  		unsigned long memsize, void *boarddata)
>  {
>  	unsigned long endmem = membase + memsize;
> @@ -233,6 +234,8 @@ __noreturn void barebox_non_pbl_start(unsigned long membase,
>  	pr_debug("initializing malloc pool at 0x%08lx (size 0x%08lx)\n",
>  			malloc_start, malloc_end - malloc_start);
>  
> +	kasan_init(membase, memsize, malloc_start - (memsize >> KASAN_SHADOW_SCALE_SHIFT));
> +
>  	mem_malloc_init((void *)malloc_start, (void *)malloc_end - 1);
>  
>  	if (IS_ENABLED(CONFIG_BOOTM_OPTEE))
> @@ -259,7 +262,7 @@ void start(unsigned long membase, unsigned long memsize, void *boarddata);
>   * First function in the uncompressed image. We get here from
>   * the pbl. The stack already has been set up by the pbl.
>   */
> -void NAKED __section(.text_entry) start(unsigned long membase,
> +void NAKED __no_sanitize_address __section(.text_entry) start(unsigned long membase,
>  		unsigned long memsize, void *boarddata)
>  {
>  	barebox_non_pbl_start(membase, memsize, boarddata);
> diff --git a/arch/arm/include/asm/string.h b/arch/arm/include/asm/string.h
> index 435647abda..fb577cfcd5 100644
> --- a/arch/arm/include/asm/string.h
> +++ b/arch/arm/include/asm/string.h
> @@ -5,8 +5,10 @@
>  
>  #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_MEMSET
>  extern void *memset(void *, int, __kernel_size_t);
> +extern void *__memset(void *, int, __kernel_size_t);
>  
>  #endif
>  
> diff --git a/arch/arm/lib32/barebox.lds.S b/arch/arm/lib32/barebox.lds.S
> index ed279279a2..54d9b3e381 100644
> --- a/arch/arm/lib32/barebox.lds.S
> +++ b/arch/arm/lib32/barebox.lds.S
> @@ -77,7 +77,9 @@ SECTIONS
>  	_sdata = .;
>  
>  	. = ALIGN(4);
> -	.data : { *(.data*) }
> +	.data : { *(.data*)
> +		CONSTRUCTORS
> +	}
>  
>  	.barebox_imd : { BAREBOX_IMD }
>  
> diff --git a/arch/arm/lib32/memcpy.S b/arch/arm/lib32/memcpy.S
> index 5123691ca9..0fcdaa88e6 100644
> --- a/arch/arm/lib32/memcpy.S
> +++ b/arch/arm/lib32/memcpy.S
> @@ -56,9 +56,12 @@
>  
>  /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
>  
> +.weak memcpy
>  ENTRY(memcpy)
> +ENTRY(__memcpy)
>  
>  #include "copy_template.S"
>  
> +ENDPROC(__memcpy)
>  ENDPROC(memcpy)
>  
> diff --git a/arch/arm/lib32/memset.S b/arch/arm/lib32/memset.S
> index c4d2672038..6079dd89f6 100644
> --- a/arch/arm/lib32/memset.S
> +++ b/arch/arm/lib32/memset.S
> @@ -15,6 +15,8 @@
>  	.text
>  	.align	5
>  
> +.weak memset
> +ENTRY(__memset)
>  ENTRY(memset)
>  	ands	r3, r0, #3		@ 1 unaligned?
>  	mov	ip, r0			@ preserve r0 as return value
> @@ -121,4 +123,4 @@ ENTRY(memset)
>  	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
>  	b	1b
>  ENDPROC(memset)
> -
> +ENDPROC(__memset)
> diff --git a/arch/arm/lib64/string.c b/arch/arm/lib64/string.c
> index cb26331527..a2cf09e58e 100644
> --- a/arch/arm/lib64/string.c
> +++ b/arch/arm/lib64/string.c
> @@ -5,18 +5,34 @@
>  void *__arch_memset(void *dst, int c, __kernel_size_t size);
>  void *__arch_memcpy(void * dest, const void *src, size_t count);
>  
> -void *memset(void *dst, int c, __kernel_size_t size)
> +static void *_memset(void *dst, int c, __kernel_size_t size)
>  {
>  	if (likely(get_cr() & CR_M))
>  		return __arch_memset(dst, c, size);
>  
> -	return __default_memset(dst, c, size);
> +	return __nokasan_default_memset(dst, c, size);
>  }
>  
> -void *memcpy(void * dest, const void *src, size_t count)
> +void __weak *memset(void *dst, int c, __kernel_size_t size)
> +{
> +	return _memset(dst, c, size);
> +}
> +
> +void *__memset(void *dst, int c, __kernel_size_t size)
> +	__alias(_memset);
> +
> +static void *_memcpy(void * dest, const void *src, size_t count)
>  {
>  	if (likely(get_cr() & CR_M))
>  		return __arch_memcpy(dest, src, count);
>  
> -	return __default_memcpy(dest, src, count);
> -}
> \ No newline at end of file
> +	return __nokasan_default_memcpy(dest, src, count);
> +}
> +
> +void __weak *memcpy(void * dest, const void *src, size_t count)
> +{
> +	return _memcpy(dest, src, count);
> +}
> +
> +void *__memcpy(void * dest, const void *src, size_t count)
> +	__alias(_memcpy);
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
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  reply	other threads:[~2021-02-09  9:26 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18  8:45 [PATCH 0/9] barebox " Sascha Hauer
2020-09-18  8:45 ` [PATCH 1/9] Add print_hex_dump kernel implementation Sascha Hauer
2020-09-18  8:45 ` [PATCH 2/9] Add _RET_IP_ macro Sascha Hauer
2020-09-18  8:45 ` [PATCH 3/9] Kallsyms: Also resolve global variables Sascha Hauer
2020-09-22 16:17   ` Michael Grzeschik
2020-09-28  8:30     ` Sascha Hauer
2020-09-18  8:45 ` [PATCH 4/9] Add constructor support Sascha Hauer
2020-09-18  8:45 ` [PATCH 5/9] pbl: Alias memcpy and memset Sascha Hauer
2020-09-18  8:45 ` [PATCH 6/9] string: Add nokasan variants of default memcpy/memset Sascha Hauer
2020-09-18  8:45 ` [PATCH 7/9] sandbox: rename KASan to ASan Sascha Hauer
2020-09-18  8:45 ` [PATCH 8/9] Add KASan support Sascha Hauer
2020-09-18 10:15   ` Ahmad Fatoum
2020-09-21  6:24     ` Sascha Hauer
2020-09-18  8:45 ` [PATCH 9/9] ARM: " Sascha Hauer
2021-02-09  9:25   ` Ahmad Fatoum [this message]
2021-02-10  9:26     ` Sascha Hauer
2021-02-10  9:27       ` Ahmad Fatoum
2020-09-28 14:33 ` [PATCH 0/9] barebox " Ahmad Fatoum
2020-09-28 15:06   ` Sascha Hauer

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