cfg80211/mac80211: fix BSS leaks when abandoning assoc attempts

When mac80211 abandons an association attempt, it may free
all the data structures, but inform cfg80211 and userspace
about it only by sending the deauth frame it received, in
which case cfg80211 has no link to the BSS struct that was
used and will not cfg80211_unhold_bss() it.

Fix this by providing a way to inform cfg80211 of this with
the BSS entry passed, so that it can clean up properly, and
use this ability in the appropriate places in mac80211.

This isn't ideal: some code is more or less duplicated and
tracing is missing. However, it's a fairly small change and
it's thus easier to backport - cleanups can come later.

Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d157b250ff77..098ce9b179ee 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2518,7 +2518,7 @@ static void ieee80211_destroy_auth_data(struct ieee80211_sub_if_data *sdata,
 }
 
 static void ieee80211_destroy_assoc_data(struct ieee80211_sub_if_data *sdata,
-                                         bool assoc)
+                                         bool assoc, bool abandon)
 {
         struct ieee80211_mgd_assoc_data *assoc_data = sdata->u.mgd.assoc_data;
 
@@ -2541,6 +2541,9 @@ static void ieee80211_destroy_assoc_data(struct ieee80211_sub_if_data *sdata,
                 mutex_lock(&sdata->local->mtx);
                 ieee80211_vif_release_channel(sdata);
                 mutex_unlock(&sdata->local->mtx);
+
+                if (abandon)
+                        cfg80211_abandon_assoc(sdata->dev, assoc_data->bss);
         }
 
         kfree(assoc_data);
@@ -2773,7 +2776,7 @@ static void ieee80211_rx_mgmt_deauth(struct ieee80211_sub_if_data *sdata,
                            bssid, reason_code,
                            ieee80211_get_reason_code_string(reason_code));
 
-                ieee80211_destroy_assoc_data(sdata, false);
+                ieee80211_destroy_assoc_data(sdata, false, true);
 
                 cfg80211_rx_mlme_mgmt(sdata->dev, (u8 *)mgmt, len);
                 return;
@@ -3182,14 +3185,14 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
         if (status_code != WLAN_STATUS_SUCCESS) {
                 sdata_info(sdata, "%pM denied association (code=%d)\n",
                            mgmt->sa, status_code);
-                ieee80211_destroy_assoc_data(sdata, false);
+                ieee80211_destroy_assoc_data(sdata, false, false);
                 event.u.mlme.status = MLME_DENIED;
                 event.u.mlme.reason = status_code;
                 drv_event_callback(sdata->local, sdata, &event);
         } else {
                 if (!ieee80211_assoc_success(sdata, bss, mgmt, len)) {
                         /* oops -- internal error -- send timeout for now */
-                        ieee80211_destroy_assoc_data(sdata, false);
+                        ieee80211_destroy_assoc_data(sdata, false, false);
                         cfg80211_assoc_timeout(sdata->dev, bss);
                         return;
                 }
@@ -3202,7 +3205,7 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
                  * recalc after assoc_data is NULL but before associated
                  * is set can cause the interface to go idle
                  */
-                ieee80211_destroy_assoc_data(sdata, true);
+                ieee80211_destroy_assoc_data(sdata, true, false);
 
                 /* get uapsd queues configuration */
                 uapsd_queues = 0;
@@ -3901,7 +3904,7 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
                                 .u.mlme.status = MLME_TIMEOUT,
                         };
 
-                        ieee80211_destroy_assoc_data(sdata, false);
+                        ieee80211_destroy_assoc_data(sdata, false, false);
                         cfg80211_assoc_timeout(sdata->dev, bss);
                         drv_event_callback(sdata->local, sdata, &event);
                 }
@@ -4040,7 +4043,7 @@ void ieee80211_mgd_quiesce(struct ieee80211_sub_if_data *sdata)
                                                WLAN_REASON_DEAUTH_LEAVING,
                                                false, frame_buf);
                 if (ifmgd->assoc_data)
-                        ieee80211_destroy_assoc_data(sdata, false);
+                        ieee80211_destroy_assoc_data(sdata, false, true);
                 if (ifmgd->auth_data)
                         ieee80211_destroy_auth_data(sdata, false);
                 cfg80211_tx_mlme_mgmt(sdata->dev, frame_buf,
@@ -4949,7 +4952,7 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
                                                IEEE80211_STYPE_DEAUTH,
                                                req->reason_code, tx,
                                                frame_buf);
-                ieee80211_destroy_assoc_data(sdata, false);
+                ieee80211_destroy_assoc_data(sdata, false, true);
                 ieee80211_report_disconnect(sdata, frame_buf,
                                             sizeof(frame_buf), true,
                                             req->reason_code);
@@ -5024,7 +5027,7 @@ void ieee80211_mgd_stop(struct ieee80211_sub_if_data *sdata)
         sdata_lock(sdata);
         if (ifmgd->assoc_data) {
                 struct cfg80211_bss *bss = ifmgd->assoc_data->bss;
-                ieee80211_destroy_assoc_data(sdata, false);
+                ieee80211_destroy_assoc_data(sdata, false, false);
                 cfg80211_assoc_timeout(sdata->dev, bss);
         }
         if (ifmgd->auth_data)