mac80211: fix RX skb leaks

In mac80211's RX path some of the warnings that
warn about drivers passing invalid status values
leak the skb, fix that by refactoring the code.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 15 insertions, 19 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b98f1afbfebf..c01588f9d453 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2447,17 +2447,13 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
         struct ieee80211_supported_band *sband;
         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 
-        if (status->band < 0 ||
-            status->band >= IEEE80211_NUM_BANDS) {
-                WARN_ON(1);
-                return;
-        }
+        if (WARN_ON(status->band < 0 ||
+                    status->band >= IEEE80211_NUM_BANDS))
+                goto drop;
 
         sband = local->hw.wiphy->bands[status->band];
-        if (!sband) {
-                WARN_ON(1);
-                return;
-        }
+        if (WARN_ON(!sband))
+                goto drop;
 
         /*
          * If we're suspending, it is possible although not too likely
@@ -2466,25 +2462,21 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
          * that might, for example, cause stations to be added or other
          * driver callbacks be invoked.
          */
-        if (unlikely(local->quiescing || local->suspended)) {
-                kfree_skb(skb);
-                return;
-        }
+        if (unlikely(local->quiescing || local->suspended))
+                goto drop;
 
         /*
          * The same happens when we're not even started,
          * but that's worth a warning.
          */
-        if (WARN_ON(!local->started)) {
-                kfree_skb(skb);
-                return;
-        }
+        if (WARN_ON(!local->started))
+                goto drop;
 
         if (status->flag & RX_FLAG_HT) {
                 /* rate_idx is MCS index */
                 if (WARN_ON(status->rate_idx < 0 ||
                             status->rate_idx >= 76))
-                        return;
+                        goto drop;
                 /* HT rates are not in the table - use the highest legacy rate
                  * for now since other parts of mac80211 may not yet be fully
                  * MCS aware. */
@@ -2492,7 +2484,7 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
         } else {
                 if (WARN_ON(status->rate_idx < 0 ||
                             status->rate_idx >= sband->n_bitrates))
-                        return;
+                        goto drop;
                 rate = &sband->bitrates[status->rate_idx];
         }
 
@@ -2531,6 +2523,10 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
                 __ieee80211_rx_handle_packet(hw, skb, rate);
 
         rcu_read_unlock();
+
+        return;
+ drop:
+        kfree_skb(skb);
 }
 EXPORT_SYMBOL(ieee80211_rx);