--- if_sl.c.orig
+++ if_sl.c
@@ -214,8 +214,14 @@
 		ifq_set_ready(&sc->sc_if.if_snd);
 		sc->sc_fastq.ifq_maxlen = 32;
+		/*
+		 * Do NOT register the raw softc as the link MIB:
+		 * net.link.generic.ifdata.<idx>.linkspecific is
+		 * world-readable and sizeof(struct sl_softc) bytes of
+		 * it (embedded struct ifnet with function pointers,
+		 * tty/buffer pointers, callout c_func pointers) would
+		 * be disclosed to any local user.  DF-3469.
+		 */
+		sc->sc_if.if_linkmib = NULL;
+		sc->sc_if.if_linkmiblen = 0;
-		sc->sc_if.if_linkmib = sc;
-		sc->sc_if.if_linkmiblen = sizeof *sc;
 		callout_init_mp(&sc->sc_oftimeout);
 		callout_init_mp(&sc->sc_katimeout);
 		if_attach(&sc->sc_if, NULL);