Add compile-time checks as well

1 files changed, 10 insertions, 0 deletions

diff --git a/include/strings.h b/include/strings.h
index c2f3bcd..4086fe4 100644
--- a/include/strings.h
+++ b/include/strings.h
@@ -6,26 +6,36 @@
 
 #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0
 
+#define __errordecl(name, msg) extern void name(void) __attribute__((__error__(msg)))
+
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) || defined(_POSIX_SOURCE) \
  || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE+0 < 200809L) \
  || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE+0 < 700)
+__errordecl(__bcopy_error, "bcopy: buffer overflow detected");
 static inline __attribute__ ((always_inline))
 void
 __fortify_bcopy(const void *__restrict src, void *__restrict dest, size_t n)
 {
         size_t bos = __builtin_object_size(dest, 0);
 
+        if (__builtin_constant_p(n) && n > bos)
+                __bcopy_error();
+
         if (n > bos)
                 __builtin_trap();
         return bcopy(src, dest, n);
 }
 
+__errordecl(__bzero_error, "bzero: buffer overflow detected");
 static inline __attribute__ ((always_inline))
 void
 __fortify_bzero(void *src, size_t n)
 {
         size_t bos = __builtin_object_size(src, 0);
 
+        if (__builtin_constant_p(n) && n > bos)
+                __bzero_error();
+
         if (n > bos)
                 __builtin_trap();
         return bzero(src, n);