diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index 47ff5c4..b8e3cb1 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -167,51 +167,9 @@
 int mknod(const char*, mode_t, dev_t);
 mode_t umask(mode_t) __overloadable __RENAME_CLANG(umask);
 
-mode_t __umask_chk(mode_t) __INTRODUCED_IN(18);
-
-#if defined(__BIONIC_FORTIFY)
-#define __umask_invalid_mode_str "umask called with invalid mode"
-
-#if defined(__clang__)
-
-#if __ANDROID_API__ >= __ANDROID_API_J_MR2__
-/*
- * Abuse enable_if to make these be seen as overloads of umask, rather than
- * definitions.
- */
-__BIONIC_ERROR_FUNCTION_VISIBILITY
-mode_t umask(mode_t mode) __overloadable
-        __enable_if(1, "")
-        __enable_if(mode & ~0777, __umask_invalid_mode_str)
-        __errorattr(__umask_invalid_mode_str);
-
-__BIONIC_FORTIFY_INLINE
-mode_t umask(mode_t mode) __enable_if(1, "") __overloadable {
-  return __umask_chk(mode);
-}
-#endif /* __ANDROID_API__ >= __ANDROID_API_J_MR2__ */
-
-#else /* defined(__clang__) */
-__errordecl(__umask_invalid_mode, __umask_invalid_mode_str);
-extern mode_t __umask_real(mode_t) __RENAME(umask);
-
-#if __ANDROID_API__ >= __ANDROID_API_J_MR2__
-__BIONIC_FORTIFY_INLINE
-mode_t umask(mode_t mode) {
-  if (__builtin_constant_p(mode)) {
-    if ((mode & 0777) != mode) {
-      __umask_invalid_mode();
-    }
-    return __umask_real(mode);
-  }
-  return __umask_chk(mode);
-}
-#endif /* __ANDROID_API__ >= __ANDROID_API_J_MR2__ */
-
-#endif /* defined(__clang__) */
-#undef __umask_invalid_mode_str
-
-#endif /* defined(__BIONIC_FORTIFY) */
+#if defined(__BIONIC_INCLUDE_FORTIFY_HEADERS)
+#include <bits/fortify/stat.h>
+#endif
 
 #if __ANDROID_API__ >= __ANDROID_API_L__
 int mkfifo(const char*, mode_t) __INTRODUCED_IN(21);