mac80211: fix offchannel TX cookie matching

When I introduced in-kernel off-channel TX I
introduced a bug -- the work can't be canceled
again because the code clear the skb pointer.
Fix this by keeping track separately of whether
TX status has already been reported.

Cc: stable@kernel.org [2.6.38+]
Reported-by: Jouni Malinen <j@w1.fi>
Tested-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 4 insertions, 3 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1309bb9c97be..d0705f260178 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1886,7 +1886,7 @@ ieee80211_offchan_tx_done(struct ieee80211_work *wk, struct sk_buff *skb)
          * so in that case userspace will have to deal with it.
          */
 
-        if (wk->offchan_tx.wait && wk->offchan_tx.frame)
+        if (wk->offchan_tx.wait && !wk->offchan_tx.status)
                 cfg80211_mgmt_tx_status(wk->sdata->dev,
                                         (unsigned long) wk->offchan_tx.frame,
                                         wk->ie, wk->ie_len, false, GFP_KERNEL);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9fa5f8a674bc..810d7b6a5567 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -346,6 +346,7 @@ struct ieee80211_work {
                 struct {
                         struct sk_buff *frame;
                         u32 wait;
+                        bool status;
                 } offchan_tx;
         };
 
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 864a9c3bcf46..f3d710705e76 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -429,7 +429,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                                 continue;
                         if (wk->offchan_tx.frame != skb)
                                 continue;
-                        wk->offchan_tx.frame = NULL;
+                        wk->offchan_tx.status = true;
                         break;
                 }
                 rcu_read_unlock();
diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index af374fab1a12..94472eb34d76 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -577,7 +577,7 @@ ieee80211_offchannel_tx(struct ieee80211_work *wk)
                 /*
                  * After this, offchan_tx.frame remains but now is no
                  * longer a valid pointer -- we still need it as the
-                 * cookie for canceling this work.
+                 * cookie for canceling this work/status matching.
                  */
                 ieee80211_tx_skb(wk->sdata, wk->offchan_tx.frame);