2 files changed, 8 insertions, 1 deletions
diff --git a/newlib/libc/stdlib/wctomb.c b/newlib/libc/stdlib/wctomb.c
index f2c62496f..2ab7b0339 100644
--- a/newlib/libc/stdlib/wctomb.c
+++ b/newlib/libc/stdlib/wctomb.c
@@ -48,6 +48,7 @@ effects vary with the locale.
 
 #include <newlib.h>
 #include <stdlib.h>
+#include <errno.h>
 
 int
 _DEFUN (wctomb, (s, wchar),
@@ -62,6 +63,12 @@ _DEFUN (wctomb, (s, wchar),
         if (s == NULL)
                 return 0;
 
+	/* Verify that wchar is a valid single-byte character.  */
+	if ((size_t)wchar >= 0x100) {
+		errno = EILSEQ;
+		return -1;
+	}
+
         *s = (char) wchar;
         return 1;
 #endif /* not _MB_CAPABLE */
diff --git a/newlib/libc/stdlib/wctomb_r.c b/newlib/libc/stdlib/wctomb_r.c
index 11418b564..b5205fcaa 100644
--- a/newlib/libc/stdlib/wctomb_r.c
+++ b/newlib/libc/stdlib/wctomb_r.c
@@ -207,7 +207,7 @@ _DEFUN (_wctomb_r, (r, s, wchar, state),
     return 0;
  
   /* otherwise we are dealing with a single byte character */
-  if (wchar >= 0x100)
+  if ((size_t)wchar >= 0x100)
     {
       r->_errno = EILSEQ;
       return -1;