arm64/uaccess: Enable hardened usercopy
Enables CONFIG_HARDENED_USERCOPY checks on arm64. As done by KASAN in -next,
renames the low-level functions to __arch_copy_*_user() so a static inline
can do additional work before the copy.
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 9e397a5..92848b0 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -256,24 +256,39 @@
-EFAULT; \
})
-extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
-extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
+extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
+extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
+static inline unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ check_object_size(to, n, false);
+ return __arch_copy_from_user(to, from, n);
+}
+
+static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ check_object_size(from, n, true);
+ return __arch_copy_to_user(to, from, n);
+}
+
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
- if (access_ok(VERIFY_READ, from, n))
- n = __copy_from_user(to, from, n);
- else /* security hole - plug it */
+ if (access_ok(VERIFY_READ, from, n)) {
+ check_object_size(to, n, false);
+ n = __arch_copy_from_user(to, from, n);
+ } else /* security hole - plug it */
memset(to, 0, n);
return n;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
{
- if (access_ok(VERIFY_WRITE, to, n))
- n = __copy_to_user(to, from, n);
+ if (access_ok(VERIFY_WRITE, to, n)) {
+ check_object_size(from, n, true);
+ n = __arch_copy_to_user(to, from, n);
+ }
return n;
}