[PATCH 9/9] ARM: Add KASan support
Sascha Hauer
s.hauer at pengutronix.de
Fri Sep 18 04:45:32 EDT 2020
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 at pengutronix.de>
---
arch/arm/Kconfig | 1 +
arch/arm/cpu/Makefile | 2 ++
arch/arm/cpu/common.c | 2 +-
arch/arm/cpu/setupc.S | 6 +++---
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);
--
2.28.0
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