MIPS: Enable hardened usercopy

Enable CONFIG_HARDENED_USERCOPY checks for MIPS, calling check_object
size in all of copy_{to,from}_user(), __copy_{to,from}_user() &
__copy_{to,from}_user_inatomic().
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14371/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -66,6 +66,7 @@ config MIPS
 	select HANDLE_DOMAIN_IRQ
 	select HAVE_EXIT_THREAD
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_ARCH_HARDENED_USERCOPY
 
 menu "Machine selection"
 

arch/mips/include/asm/uaccess.h

@@ -858,7 +858,10 @@ extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_from, __cu_len, true);			\
 	might_fault();							\
+									\
 	if (eva_kernel_access())					\
 		__cu_len = __invoke_copy_to_kernel(__cu_to, __cu_from,	\
 						   __cu_len);		\
@@ -879,6 +882,9 @@ extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_from, __cu_len, true);			\
+									\
 	if (eva_kernel_access())					\
 		__cu_len = __invoke_copy_to_kernel(__cu_to, __cu_from,	\
 						   __cu_len);		\
@@ -897,6 +903,9 @@ extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_to, __cu_len, false);			\
+									\
 	if (eva_kernel_access())					\
 		__cu_len = __invoke_copy_from_kernel_inatomic(__cu_to,	\
 							      __cu_from,\
@@ -931,6 +940,9 @@ extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_from, __cu_len, true);			\
+									\
 	if (eva_kernel_access()) {					\
 		__cu_len = __invoke_copy_to_kernel(__cu_to,		\
 						   __cu_from,		\
@@ -1123,6 +1135,9 @@ extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_to, __cu_len, false);			\
+									\
 	if (eva_kernel_access()) {					\
 		__cu_len = __invoke_copy_from_kernel(__cu_to,		\
 						     __cu_from,		\
@@ -1161,6 +1176,9 @@ extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
 	__cu_to = (to);							\
 	__cu_from = (from);						\
 	__cu_len = (n);							\
+									\
+	check_object_size(__cu_to, __cu_len, false);			\
+									\
 	if (eva_kernel_access()) {					\
 		__cu_len = __invoke_copy_from_kernel(__cu_to,		\
 						     __cu_from,		\