check name offset

diff --git a/util/led/extract.c b/util/led/extract.c
index b03380b..38aba4b 100644 (file)
--- a/util/led/extract.c
+++ b/util/led/extract.c
@@ -72,8 +72,12 @@ get_names(head)
                 * area, so we don't have to be afraid to confuse "no name"
                 * with "the first name".
                 */
-               if (name.on_foff)
+               if (name.on_foff) {
+                       if (name.on_foff < 0 || name.on_foff >= charoff) {
+                               fatal("illegal offset in name");
+                       }
                        name.on_foff += charindex - charoff;
+               }
                namerelocate(&name);
                if (name.on_type & S_EXT) {
                        getexternal(&name);