Fix stray null write: replace sizeof(buf) with *buf = '\0' in var_subst()

Agent-Logs-Url: https://github.com/tbamud/tbamud/sessions/339cbdde-5de4-4f33-aea6-82df3efbd9c4

Co-authored-by: welcor <357770+welcor@users.noreply.github.com>

src/dg_variables.c

@@ -1636,13 +1636,6 @@ void var_subst(void *go, struct script_data *sc, trig_data *trig,
   int paren_count = 0;
   int dots = 0;
 
-  /* reject lines that would overflow our fixed-size buffers */
-  if (strnlen(line, MAX_INPUT_LENGTH) >= MAX_INPUT_LENGTH) {
-    script_log("Trigger VNum %d: variable substitution line too long, ignoring.", GET_TRIG_VNUM(trig));
-    *buf = '\0';
-    return;
-  }
-
   /* skip out if no %'s */
   if (!strchr(line, '%')) {
     strcpy(buf, line);
@@ -1729,5 +1722,5 @@ void var_subst(void *go, struct script_data *sc, trig_data *trig,
       left -= len;
     } /* else if *p .. */
   } /* while *p .. */
-  buf[sizeof(buf) - 1] = '\0';
+  *buf = '\0';
 }