powerpc: prepare string/mem functions for KASAN

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 commit 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@c-s.fr>
[mpe: Fixups to keep selftests working]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
new file mode 100644 (file)
index 0000000..2c179a3
--- /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)      _GLOBAL(__##fn)
+#define _GLOBAL_TOC_KASAN(fn)  _GLOBAL_TOC(__##fn)
+#define EXPORT_SYMBOL_KASAN(fn)        EXPORT_SYMBOL(__##fn)
+#else
+#define _GLOBAL_KASAN(fn)      _GLOBAL(fn)
+#define _GLOBAL_TOC_KASAN(fn)  _GLOBAL_TOC(fn)
+#define EXPORT_SYMBOL_KASAN(fn)
+#endif
+
+#endif

diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index 1647de15a31e7186e438054f99197cf38233a9f9..9bf6dffb40900aeafeeccb3236c26f81519d451e 100644 (file)
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -4,14 +4,17 @@
 
 #ifdef __KERNEL__
 
+#ifndef CONFIG_KASAN
 #define __HAVE_ARCH_STRNCPY
 #define __HAVE_ARCH_STRNCMP
+#define __HAVE_ARCH_MEMCHR
+#define __HAVE_ARCH_MEMCMP
+#define __HAVE_ARCH_MEMSET16
+#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
 
 extern char * strcpy(char *,const char *);
@@ -27,7 +30,27 @@ 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
+#ifndef CONFIG_KASAN
 #define __HAVE_ARCH_MEMSET32
 #define __HAVE_ARCH_MEMSET64
 
@@ -49,8 +72,11 @@ static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n)
 {
        return __memset64(p, v, n * 8);
 }
+#endif
 #else
+#ifndef CONFIG_KASAN
 #define __HAVE_ARCH_STRLEN
+#endif
 
 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
 #endif

diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 667df97d259548fdb600ed4cb116f5517208ed0a..181fd10008efbf2b6ef0033f85558174689f644a 100644 (file)
--- 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
+       MEM_FUNCS="__memcpy __memset"
+else
+       MEM_FUNCS="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 $MEM_FUNCS 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 79396e184bcaaac71f120e0a88058bc7a3d2c182..47a4de434c22a4197ee4afd36bee253d1ff0a39c 100644 (file)
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -8,9 +8,14 @@ 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
 
-obj-$(CONFIG_PPC32)    += div64.o copy_32.o crtsavres.o strlen_32.o
+ifndef CONFIG_KASAN
+obj-y  +=      string.o memcmp_$(BITS).o
+obj-$(CONFIG_PPC32)    += strlen_32.o
+endif
+
+obj-$(CONFIG_PPC32)    += div64.o copy_32.o crtsavres.o
 
 obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
 
@@ -34,7 +39,7 @@ obj64-$(CONFIG_KPROBES_SANITY_TEST)   += test_emulate_step.o \
                                           test_emulate_step_exec_instr.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 ba66846fe973f674fc67a1faec9d83a4e5740beb..d5642481fb9858f94e53da1c28a84320d11fe769 100644 (file)
--- 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);       \
@@ -68,6 +69,7 @@ CACHELINE_BYTES = L1_CACHE_BYTES
 LG_CACHELINE_BYTES = L1_CACHE_SHIFT
 CACHELINE_MASK = (L1_CACHE_BYTES-1)
 
+#ifndef CONFIG_KASAN
 _GLOBAL(memset16)
        rlwinm. r0 ,r5, 31, 1, 31
        addi    r6, r3, -4
@@ -81,6 +83,7 @@ _GLOBAL(memset16)
        sth     r4, 4(r6)
        blr
 EXPORT_SYMBOL(memset16)
+#endif
 
 /*
  * Use dcbz on the complete cache lines in the destination
@@ -91,7 +94,7 @@ 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
 
@@ -151,6 +154,7 @@ _GLOBAL(memset)
        bdnz    9b
        blr
 EXPORT_SYMBOL(memset)
+EXPORT_SYMBOL_KASAN(memset)
 
 /*
  * This version uses dcbz on the complete cache lines in the
@@ -163,12 +167,12 @@ 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
 
@@ -244,6 +248,8 @@ _GLOBAL(memcpy)
 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 3c3be02f33b7cb12bf14e7bbe5b554b1967c1eb9..7f6bd031c3062041c8f89877098414d198b3e20e 100644 (file)
--- a/arch/powerpc/lib/mem_64.S
+++ b/arch/powerpc/lib/mem_64.S
@@ -12,7 +12,9 @@
 #include <asm/errno.h>
 #include <asm/ppc_asm.h>
 #include <asm/export.h>
+#include <asm/kasan.h>
 
+#ifndef CONFIG_KASAN
 _GLOBAL(__memset16)
        rlwimi  r4,r4,16,0,15
        /* fall through */
@@ -29,8 +31,9 @@ _GLOBAL(__memset64)
 EXPORT_SYMBOL(__memset16)
 EXPORT_SYMBOL(__memset32)
 EXPORT_SYMBOL(__memset64)
+#endif
 
-_GLOBAL(memset)
+_GLOBAL_KASAN(memset)
        neg     r0,r3
        rlwimi  r4,r4,8,16,23
        andi.   r0,r0,7                 /* # bytes to be 8-byte aligned */
@@ -96,8 +99,9 @@ _GLOBAL(memset)
        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
@@ -139,3 +143,4 @@ _GLOBAL(backwards_memcpy)
        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 273ea67e60a131b9d8cb9472d835e2867c02d6fc..25c3772c1dfbca34703bcd1fb9984d3cf47d6e3b 100644 (file)
--- a/arch/powerpc/lib/memcpy_64.S
+++ b/arch/powerpc/lib/memcpy_64.S
@@ -11,6 +11,7 @@
 #include <asm/export.h>
 #include <asm/asm-compat.h>
 #include <asm/feature-fixups.h>
+#include <asm/kasan.h>
 
 #ifndef SELFTEST_CASE
 /* For big-endian, 0 == most CPUs, 1 == POWER6, 2 == Cell */
@@ -18,7 +19,7 @@
 #endif
 
        .align  7
-_GLOBAL_TOC(memcpy)
+_GLOBAL_TOC_KASAN(memcpy)
 BEGIN_FTR_SECTION
 #ifdef __LITTLE_ENDIAN__
        cmpdi   cr7,r5,0
@@ -230,3 +231,4 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
        blr
 #endif
 EXPORT_SYMBOL(memcpy)
+EXPORT_SYMBOL_KASAN(memcpy)

diff --git a/tools/testing/selftests/powerpc/copyloops/asm/export.h b/tools/testing/selftests/powerpc/copyloops/asm/export.h
index 0bab35f6777a204ef2fc1e85a1e5eb4eb62e349d..05c1663c89b03717f2aed15534d0d2a023216c82 100644 (file)
--- a/tools/testing/selftests/powerpc/copyloops/asm/export.h
+++ b/tools/testing/selftests/powerpc/copyloops/asm/export.h
@@ -1,2 +1,3 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #define EXPORT_SYMBOL(x)
+#define EXPORT_SYMBOL_KASAN(x)

diff --git a/tools/testing/selftests/powerpc/copyloops/asm/kasan.h b/tools/testing/selftests/powerpc/copyloops/asm/kasan.h
new file mode 100644 (file)
index 0000000..e69de29

diff --git a/tools/testing/selftests/powerpc/copyloops/asm/ppc_asm.h b/tools/testing/selftests/powerpc/copyloops/asm/ppc_asm.h
index 0605df80759329b6865ffc1382fa13f18933db65..58c1cef3e399d5afd17fa11f2f9c8236de59a7df 100644 (file)
--- a/tools/testing/selftests/powerpc/copyloops/asm/ppc_asm.h
+++ b/tools/testing/selftests/powerpc/copyloops/asm/ppc_asm.h
@@ -25,6 +25,7 @@
 
 #define _GLOBAL(A) FUNC_START(test_ ## A)
 #define _GLOBAL_TOC(A) _GLOBAL(A)
+#define _GLOBAL_TOC_KASAN(A) _GLOBAL(A)
 
 #define PPC_MTOCRF(A, B)       mtocrf A, B