mac80211: fix use after free

roc is destroyed then roc->started is referenced. Keep a local cache.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 8c047fc..635c325 100644 (file)
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -324,6 +324,7 @@ void ieee80211_sw_roc_work(struct work_struct *work)
                container_of(work, struct ieee80211_roc_work, work.work);
        struct ieee80211_sub_if_data *sdata = roc->sdata;
        struct ieee80211_local *local = sdata->local;
+       bool started;
 
        mutex_lock(&local->mtx);
 
@@ -366,9 +367,10 @@ void ieee80211_sw_roc_work(struct work_struct *work)
                /* finish this ROC */
  finish:
                list_del(&roc->list);
+               started = roc->started;
                ieee80211_roc_notify_destroy(roc);
 
-               if (roc->started) {
+               if (started) {
                        drv_flush(local, false);
 
                        local->tmp_channel = NULL;
@@ -379,7 +381,7 @@ void ieee80211_sw_roc_work(struct work_struct *work)
 
                ieee80211_recalc_idle(local);
 
-               if (roc->started)
+               if (started)
                        ieee80211_start_next_roc(local);
        }