wext: Filter unexpected interface added/up events

It looks like a RTM_NEWLINK event claiming the interface to be UP is
delivered just before removing an interface after having first indicated
that the interface was going down/removed. Ignore this event if the
interface is not present anymore at the moment the event is processed.
This fixes issues where an interface that was re-added after being
removed did not get reconfigured properly.

Signed-hostap: Jouni Malinen <j@w1.fi>
intended-for: hostap-1

src/drivers/driver_wext.c

@@ -569,10 +569,28 @@ static void wpa_driver_wext_event_link(struct wpa_driver_wext_data *drv,
 		   del ? "removed" : "added");
 
 	if (os_strcmp(drv->ifname, event.interface_status.ifname) == 0) {
-		if (del)
+		if (del) {
+			if (drv->if_removed) {
+				wpa_printf(MSG_DEBUG, "WEXT: if_removed "
+					   "already set - ignore event");
+				return;
+			}
 			drv->if_removed = 1;
-		else
+		} else {
+			if (if_nametoindex(drv->ifname) == 0) {
+				wpa_printf(MSG_DEBUG, "WEXT: Interface %s "
+					   "does not exist - ignore "
+					   "RTM_NEWLINK",
+					   drv->ifname);
+				return;
+			}
+			if (!drv->if_removed) {
+				wpa_printf(MSG_DEBUG, "WEXT: if_removed "
+					   "already cleared - ignore event");
+				return;
+			}
 			drv->if_removed = 0;
+		}
 	}
 
 	wpa_supplicant_event(drv->ctx, EVENT_INTERFACE_STATUS, &event);
@@ -628,6 +646,7 @@ static void wpa_driver_wext_event_rtm_newlink(void *ctx, struct ifinfomsg *ifi,
 	struct wpa_driver_wext_data *drv = ctx;
 	int attrlen, rta_len;
 	struct rtattr *attr;
+	char namebuf[IFNAMSIZ];
 
 	if (!wpa_driver_wext_own_ifindex(drv, ifi->ifi_index, buf, len)) {
 		wpa_printf(MSG_DEBUG, "Ignore event for foreign ifindex %d",
@@ -650,9 +669,25 @@ static void wpa_driver_wext_event_rtm_newlink(void *ctx, struct ifinfomsg *ifi,
 	}
 
 	if (drv->if_disabled && (ifi->ifi_flags & IFF_UP)) {
-		wpa_printf(MSG_DEBUG, "WEXT: Interface up");
-		drv->if_disabled = 0;
-		wpa_supplicant_event(drv->ctx, EVENT_INTERFACE_ENABLED, NULL);
+		if (if_indextoname(ifi->ifi_index, namebuf) &&
+		    linux_iface_up(drv->ioctl_sock, drv->ifname) == 0) {
+			wpa_printf(MSG_DEBUG, "WEXT: Ignore interface up "
+				   "event since interface %s is down",
+				   namebuf);
+		} else if (if_nametoindex(drv->ifname) == 0) {
+			wpa_printf(MSG_DEBUG, "WEXT: Ignore interface up "
+				   "event since interface %s does not exist",
+				   drv->ifname);
+		} else if (drv->if_removed) {
+			wpa_printf(MSG_DEBUG, "WEXT: Ignore interface up "
+				   "event since interface %s is marked "
+				   "removed", drv->ifname);
+		} else {
+			wpa_printf(MSG_DEBUG, "WEXT: Interface up");
+			drv->if_disabled = 0;
+			wpa_supplicant_event(drv->ctx, EVENT_INTERFACE_ENABLED,
+					     NULL);
+		}
 	}
 
 	/*