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/comm.c

@@ -415,7 +415,7 @@ void copyover_recover()
 
   for (;;) {
     fOld = TRUE;
-    if (fscanf(fp, "%d %ld %511s %1023s %1023s\n", &desc, &pref, name, host, guiopt) != 5) {
+    if (fscanf(fp, "%d %ld %s %s %s\n", &desc, &pref, name, host, guiopt) != 5) {
       if(!feof(fp)) {
         if(ferror(fp))
           log("SYSERR: error reading copyover file %s: %s", COPYOVER_FILE, strerror(errno));

src/dg_variables.c

@@ -1722,5 +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';
 }