[RFC PATCH v1 1/3] kasan: move memset/memmove/memcpy interceptors in a dedicated file

[Christophe Leroy]

In preparation of the addition of interceptors for other string functions,
this patch moves memset/memmove/memcpy interceptions in string.c

Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
 mm/kasan/Makefile |  5 ++++-
 mm/kasan/common.c | 26 --------------------------
 mm/kasan/string.c | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 27 deletions(-)
 create mode 100644 mm/kasan/string.c

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 5d1065efbd47..85e91e301404 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -1,11 +1,13 @@
 # SPDX-License-Identifier: GPL-2.0
 KASAN_SANITIZE := n
 UBSAN_SANITIZE_common.o := n
+UBSAN_SANITIZE_string.o := n
 UBSAN_SANITIZE_generic.o := n
 UBSAN_SANITIZE_tags.o := n
 KCOV_INSTRUMENT := n
 
 CFLAGS_REMOVE_common.o = -pg
+CFLAGS_REMOVE_string.o = -pg
 CFLAGS_REMOVE_generic.o = -pg
 CFLAGS_REMOVE_tags.o = -pg
 
@@ -13,9 +15,10 @@ CFLAGS_REMOVE_tags.o = -pg
 # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
 
 CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
+CFLAGS_string.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
 CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
 CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
 
-obj-$(CONFIG_KASAN) := common.o init.o report.o
+obj-$(CONFIG_KASAN) := common.o init.o report.o string.o
 obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o
 obj-$(CONFIG_KASAN_SW_TAGS) += tags.o tags_report.o
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 80bbe62b16cd..3b94f484bf78 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -109,32 +109,6 @@ void kasan_check_write(const volatile void *p, unsigned int size)
 }
 EXPORT_SYMBOL(kasan_check_write);
 
-#undef memset
-void *memset(void *addr, int c, size_t len)
-{
-	check_memory_region((unsigned long)addr, len, true, _RET_IP_);
-
-	return __memset(addr, c, len);
-}
-
-#undef memmove
-void *memmove(void *dest, const void *src, size_t len)
-{
-	check_memory_region((unsigned long)src, len, false, _RET_IP_);
-	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
-
-	return __memmove(dest, src, len);
-}
-
-#undef memcpy
-void *memcpy(void *dest, const void *src, size_t len)
-{
-	check_memory_region((unsigned long)src, len, false, _RET_IP_);
-	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
-
-	return __memcpy(dest, src, len);
-}
-
 /*
  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
diff --git a/mm/kasan/string.c b/mm/kasan/string.c
new file mode 100644
index 000000000000..f23a740ff985
--- /dev/null
+++ b/mm/kasan/string.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains strings functions for KASAN
+ *
+ */
+
+#include <linux/string.h>
+
+#include "kasan.h"
+
+#undef memset
+void *memset(void *addr, int c, size_t len)
+{
+	check_memory_region((unsigned long)addr, len, true, _RET_IP_);
+
+	return __memset(addr, c, len);
+}
+
+#undef memmove
+void *memmove(void *dest, const void *src, size_t len)
+{
+	check_memory_region((unsigned long)src, len, false, _RET_IP_);
+	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
+
+	return __memmove(dest, src, len);
+}
+
+#undef memcpy
+void *memcpy(void *dest, const void *src, size_t len)
+{
+	check_memory_region((unsigned long)src, len, false, _RET_IP_);
+	check_memory_region((unsigned long)dest, len, true, _RET_IP_);
+
+	return __memcpy(dest, src, len);
+}
-- 
2.13.3