(Fformat): Validate number and type of arguments.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/editfns.c b/src/editfns.c
index 037c00d3c8b..e3863c5f117 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -1463,7 +1463,7 @@ Use %% to put a single % into the output.")
         if (*format == '%')
           format++;
         else if (++n >= nargs)
-          ;
+          error ("format string wants too many arguments");
         else if (*format == 'S')
           {
             /* For `S', prin1 the argument and then treat like a string.  */
@@ -1480,6 +1480,8 @@ Use %% to put a single % into the output.")
         else if (XTYPE (args[n]) == Lisp_String)
           {
           string:
+            if (*format != 's' && *format != 'S')
+              error ("format specifier doesn't match argument type");
             total += XSTRING (args[n])->size;
           }
         /* Would get MPV otherwise, since Lisp_Int's `point' to low memory.  */