hostapd: Make sure hapd->drv_priv gets cleared on driver deinit

Couple of code paths in hostapd.c could have left hapd->drv_priv
pointing to memory that was freed in driver_nl80211.c when a secondary
BSS interface is removed. This could result in use of freed memory and
segfault when the next driver operation (likely during interface
deinit/removal). Fix this by clearing hapd->drv_priv when there is
reason to believe that the old value is not valid within the driver
wrapper anymore.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index a4467cf0b255dd70fe820d60fa3a444f416c032c..ed7330193e792cb20312774a67fd4def997d7ade 100644 (file)
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -284,6 +284,13 @@ static void hostapd_free_hapd_data(struct hostapd_data *hapd)
                                   "Failed to remove BSS interface %s",
                                   hapd->conf->iface);
                        hapd->interface_added = 1;
+               } else {
+                       /*
+                        * Since this was a dynamically added interface, the
+                        * driver wrapper may have removed its internal instance
+                        * and hapd->drv_priv is not valid anymore.
+                        */
+                       hapd->drv_priv = NULL;
                }
        }
 
@@ -1617,8 +1624,10 @@ void hostapd_interface_deinit_free(struct hostapd_iface *iface)
        hostapd_interface_deinit(iface);
        wpa_printf(MSG_DEBUG, "%s: driver=%p drv_priv=%p -> hapd_deinit",
                   __func__, driver, drv_priv);
-       if (driver && driver->hapd_deinit && drv_priv)
+       if (driver && driver->hapd_deinit && drv_priv) {
                driver->hapd_deinit(drv_priv);
+               iface->bss[0]->drv_priv = NULL;
+       }
        hostapd_interface_free(iface);
 }