[PATCH v6 3/6] powerpc: prepare string/mem functions for KASAN
Christophe Leroy
christophe.leroy at c-s.fr
Wed Feb 20 04:23:12 AEDT 2019
CONFIG_KASAN implements wrappers for memcpy() memmove() and memset()
Those wrappers are doing the verification then call respectively
__memcpy() __memmove() and __memset(). The arches are therefore
expected to rename their optimised functions that way.
For files on which KASAN is inhibited, #defines are used to allow
them to directly call optimised versions of the functions without
going through the KASAN wrappers.
See 393f203f5fd5 ("x86_64: kasan: add interceptors for
memset/memmove/memcpy functions") for details.
Other string / mem functions do not (yet) have kasan wrappers,
we therefore have to fallback to the generic versions when
KASAN is active, otherwise KASAN checks will be skipped.
Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
arch/powerpc/include/asm/kasan.h | 15 +++++++++++++++
arch/powerpc/include/asm/string.h | 26 ++++++++++++++++++++++++--
arch/powerpc/kernel/prom_init_check.sh | 10 +++++++++-
arch/powerpc/lib/Makefile | 8 ++++++--
arch/powerpc/lib/copy_32.S | 13 +++++++------
arch/powerpc/lib/mem_64.S | 8 ++++----
arch/powerpc/lib/memcpy_64.S | 4 ++--
7 files changed, 67 insertions(+), 17 deletions(-)
create mode 100644 arch/powerpc/include/asm/kasan.h
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
new file mode 100644
index 000000000000..2efd0e42cfc9
--- /dev/null
+++ b/arch/powerpc/include/asm/kasan.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_KASAN_H
+#define __ASM_KASAN_H
+
+#ifdef CONFIG_KASAN
+#define _GLOBAL_KASAN(fn) .weak fn ; _GLOBAL(__##fn) ; _GLOBAL(fn)
+#define _GLOBAL_KASAN_TOC(fn) .weak fn ; _GLOBAL_TOC(__##fn) ; _GLOBAL_TOC(fn)
+#define EXPORT_SYMBOL_KASAN(fn) EXPORT_SYMBOL(__##fn) ; EXPORT_SYMBOL(fn)
+#else
+#define _GLOBAL_KASAN(fn) _GLOBAL(fn)
+#define _GLOBAL_KASAN_TOC(fn) _GLOBAL_TOC(fn)
+#define EXPORT_SYMBOL_KASAN(fn) EXPORT_SYMBOL(fn)
+#endif
+
+#endif
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index 1647de15a31e..2aa9ea6751cd 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -4,13 +4,16 @@
#ifdef __KERNEL__
+#ifndef CONFIG_KASAN
#define __HAVE_ARCH_STRNCPY
#define __HAVE_ARCH_STRNCMP
+#define __HAVE_ARCH_MEMCHR
+#define __HAVE_ARCH_MEMCMP
+#endif
+
#define __HAVE_ARCH_MEMSET
#define __HAVE_ARCH_MEMCPY
#define __HAVE_ARCH_MEMMOVE
-#define __HAVE_ARCH_MEMCMP
-#define __HAVE_ARCH_MEMCHR
#define __HAVE_ARCH_MEMSET16
#define __HAVE_ARCH_MEMCPY_FLUSHCACHE
@@ -27,6 +30,25 @@ extern int memcmp(const void *,const void *,__kernel_size_t);
extern void * memchr(const void *,int,__kernel_size_t);
extern void * memcpy_flushcache(void *,const void *,__kernel_size_t);
+void *__memset(void *s, int c, __kernel_size_t count);
+void *__memcpy(void *to, const void *from, __kernel_size_t n);
+void *__memmove(void *to, const void *from, __kernel_size_t n);
+
+#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
+/*
+ * For files that are 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)
+
+#ifndef __NO_FORTIFY
+#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
+#endif
+
+#endif
+
#ifdef CONFIG_PPC64
#define __HAVE_ARCH_MEMSET32
#define __HAVE_ARCH_MEMSET64
diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 667df97d2595..da6bb16e0876 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -16,8 +16,16 @@
# If you really need to reference something from prom_init.o add
# it to the list below:
+grep CONFIG_KASAN=y .config >/dev/null
+if [ $? -eq 0 ]
+then
+ MEMFCT="__memcpy __memset"
+else
+ MEMFCT="memcpy memset"
+fi
+
WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
-_end enter_prom memcpy memset reloc_offset __secondary_hold
+_end enter_prom $MEMFCT reloc_offset __secondary_hold
__secondary_hold_acknowledge __secondary_hold_spinloop __start
strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224
reloc_got2 kernstart_addr memstart_addr linux_banner _stext
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 3bf9fc6fd36c..ee08a7e1bcdf 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -8,7 +8,11 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)
-obj-y += string.o alloc.o code-patching.o feature-fixups.o
+obj-y += alloc.o code-patching.o feature-fixups.o
+
+ifndef CONFIG_KASAN
+obj-y += string.o memcmp_$(BITS).o
+endif
obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o strlen_32.o
@@ -33,7 +37,7 @@ obj64-$(CONFIG_ALTIVEC) += vmx-helper.o
obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o
obj-y += checksum_$(BITS).o checksum_wrappers.o \
- string_$(BITS).o memcmp_$(BITS).o
+ string_$(BITS).o
obj-y += sstep.o ldstfp.o quad.o
obj64-y += quad.o
diff --git a/arch/powerpc/lib/copy_32.S b/arch/powerpc/lib/copy_32.S
index ba66846fe973..57f48d99fbe3 100644
--- a/arch/powerpc/lib/copy_32.S
+++ b/arch/powerpc/lib/copy_32.S
@@ -14,6 +14,7 @@
#include <asm/ppc_asm.h>
#include <asm/export.h>
#include <asm/code-patching-asm.h>
+#include <asm/kasan.h>
#define COPY_16_BYTES \
lwz r7,4(r4); \
@@ -91,7 +92,7 @@ EXPORT_SYMBOL(memset16)
* We therefore skip the optimised bloc that uses dcbz. This jump is
* replaced by a nop once cache is active. This is done in machine_init()
*/
-_GLOBAL(memset)
+_GLOBAL_KASAN(memset)
cmplwi 0,r5,4
blt 7f
@@ -150,7 +151,7 @@ _GLOBAL(memset)
9: stbu r4,1(r6)
bdnz 9b
blr
-EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL_KASAN(memset)
/*
* This version uses dcbz on the complete cache lines in the
@@ -163,12 +164,12 @@ EXPORT_SYMBOL(memset)
* We therefore jump to generic_memcpy which doesn't use dcbz. This jump is
* replaced by a nop once cache is active. This is done in machine_init()
*/
-_GLOBAL(memmove)
+_GLOBAL_KASAN(memmove)
cmplw 0,r3,r4
bgt backwards_memcpy
/* fall through */
-_GLOBAL(memcpy)
+_GLOBAL_KASAN(memcpy)
1: b generic_memcpy
patch_site 1b, patch__memcpy_nocache
@@ -242,8 +243,8 @@ _GLOBAL(memcpy)
stbu r0,1(r6)
bdnz 40b
65: blr
-EXPORT_SYMBOL(memcpy)
-EXPORT_SYMBOL(memmove)
+EXPORT_SYMBOL_KASAN(memcpy)
+EXPORT_SYMBOL_KASAN(memmove)
generic_memcpy:
srwi. r7,r5,3
diff --git a/arch/powerpc/lib/mem_64.S b/arch/powerpc/lib/mem_64.S
index 3c3be02f33b7..57c8a940c29c 100644
--- a/arch/powerpc/lib/mem_64.S
+++ b/arch/powerpc/lib/mem_64.S
@@ -30,7 +30,7 @@ EXPORT_SYMBOL(__memset16)
EXPORT_SYMBOL(__memset32)
EXPORT_SYMBOL(__memset64)
-_GLOBAL(memset)
+_GLOBAL_KASAN(memset)
neg r0,r3
rlwimi r4,r4,8,16,23
andi. r0,r0,7 /* # bytes to be 8-byte aligned */
@@ -95,9 +95,9 @@ _GLOBAL(memset)
10: bflr 31
stb r4,0(r6)
blr
-EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL_KASAN(memset)
-_GLOBAL_TOC(memmove)
+_GLOBAL_TOC_KASAN(memmove)
cmplw 0,r3,r4
bgt backwards_memcpy
b memcpy
@@ -138,4 +138,4 @@ _GLOBAL(backwards_memcpy)
beq 2b
mtctr r7
b 1b
-EXPORT_SYMBOL(memmove)
+EXPORT_SYMBOL_KASAN(memmove)
diff --git a/arch/powerpc/lib/memcpy_64.S b/arch/powerpc/lib/memcpy_64.S
index 273ea67e60a1..2d5358cee711 100644
--- a/arch/powerpc/lib/memcpy_64.S
+++ b/arch/powerpc/lib/memcpy_64.S
@@ -18,7 +18,7 @@
#endif
.align 7
-_GLOBAL_TOC(memcpy)
+_GLOBAL_TOC_KASAN(memcpy)
BEGIN_FTR_SECTION
#ifdef __LITTLE_ENDIAN__
cmpdi cr7,r5,0
@@ -229,4 +229,4 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
4: ld r3,-STACKFRAMESIZE+STK_REG(R31)(r1) /* return dest pointer */
blr
#endif
-EXPORT_SYMBOL(memcpy)
+EXPORT_SYMBOL_KASAN(memcpy)
--
2.13.3
More information about the Linuxppc-dev
mailing list