[PATCH 2/2] kasan: use fortified strings for hwaddress sanitizer

[Arnd Bergmann]

From: Arnd Bergmann <arnd@xxxxxxxx>

GCC has separate macros for -fsanitize=kernel-address and
-fsanitize=kernel-hwaddress, and the check in the arm64 string.h
gets this wrong, which leads to string functions not getting
fortified with gcc. The newly added tests find this:

warning: unsafe memchr() usage lacked '__read_overflow' warning in /git/arm-soc/lib/test_fortify/read_overflow-memchr.c
warning: unsafe memchr_inv() usage lacked '__read_overflow' symbol in /git/arm-soc/lib/test_fortify/read_overflow-memchr_inv.c
warning: unsafe memcmp() usage lacked '__read_overflow' warning in /git/arm-soc/lib/test_fortify/read_overflow-memcmp.c
warning: unsafe memscan() usage lacked '__read_overflow' symbol in /git/arm-soc/lib/test_fortify/read_overflow-memscan.c
warning: unsafe memcmp() usage lacked '__read_overflow2' warning in /git/arm-soc/lib/test_fortify/read_overflow2-memcmp.c
warning: unsafe memcpy() usage lacked '__read_overflow2' symbol in /git/arm-soc/lib/test_fortify/read_overflow2-memcpy.c
warning: unsafe memmove() usage lacked '__read_overflow2' symbol in /git/arm-soc/lib/test_fortify/read_overflow2-memmove.c
warning: unsafe memcpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-memcpy.c
warning: unsafe memmove() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-memmove.c
warning: unsafe memset() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-memset.c
warning: unsafe strcpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strcpy-lit.c
warning: unsafe strcpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strcpy.c
warning: unsafe strlcpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strlcpy-src.c
warning: unsafe strlcpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strlcpy.c
warning: unsafe strncpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strncpy-src.c
warning: unsafe strncpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strncpy.c
warning: unsafe strscpy() usage lacked '__write_overflow' symbol in /git/arm-soc/lib/test_fortify/write_overflow-strscpy.c

Add a workaround to include/linux/compiler_types.h so we always
define __SANITIZE_ADDRESS__ for either mode, as we already do
for clang.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 include/linux/compiler_types.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index aad6f6408bfa..2f2776fffefe 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -178,6 +178,13 @@ struct ftrace_likely_data {
  */
 #define noinline_for_stack noinline
 
+/*
+ * Treat __SANITIZE_HWADDRESS__ the same as __SANITIZE_ADDRESS__ in the kernel
+ */
+#ifdef __SANITIZE_HWADDRESS__
+#define __SANITIZE_ADDRESS__
+#endif
+
 /*
  * Sanitizer helper attributes: Because using __always_inline and
  * __no_sanitize_* conflict, provide helper attributes that will either expand
-- 
2.29.2