path: root/net/mac80211
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authorJohannes Berg <johannes@sipsolutions.net>2009-11-22 12:28:41 +0100
committerJohn W. Linville <linville@tuxdriver.com>2009-11-30 13:55:51 -0500
commit827d42c9ac91ddd728e4f4a31fefb906ef2ceff7 (patch)
treee29371d79d63d0a3ec2cb6d010b71147853fc771 /net/mac80211
parentmac80211: fix two remote exploits (diff)
mac80211: fix spurious delBA handling
Lennert Buytenhek noticed that delBA handling in mac80211 was broken and has remotely triggerable problems, some of which are due to some code shuffling I did that ended up changing the order in which things were done -- this was commit d75636ef9c1af224f1097941879d5a8db7cd04e5 Author: Johannes Berg <johannes@sipsolutions.net> Date: Tue Feb 10 21:25:53 2009 +0100 mac80211: RX aggregation: clean up stop session and other parts were already present in the original commit d92684e66091c0f0101819619b315b4bb8b5bcc5 Author: Ron Rindjunsky <ron.rindjunsky@intel.com> Date: Mon Jan 28 14:07:22 2008 +0200 mac80211: A-MPDU Tx add delBA from recipient support The first problem is that I moved a BUG_ON before various checks -- thereby making it possible to hit. As the comment indicates, the BUG_ON can be removed since the ampdu_action callback must already exist when the state is != IDLE. The second problem isn't easily exploitable but there's a race condition due to unconditionally setting the state to OPERATIONAL when a delBA frame is received, even when no aggregation session was ever initiated. All the drivers accept stopping the session even then, but that opens a race window where crashes could happen before the driver accepts it. Right now, a WARN_ON may happen with non-HT drivers, while the race opens only for HT drivers. For this case, there are two things necessary to fix it: 1) don't process spurious delBA frames, and be more careful about the session state; don't drop the lock 2) HT drivers need to be prepared to handle a session stop even before the session was really started -- this is true for all drivers (that support aggregation) but iwlwifi which can be fixed easily. The other HT drivers (ath9k and ar9170) are behaving properly already. Reported-by: Lennert Buytenhek <buytenh@marvell.com> Cc: stable@kernel.org Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/mac80211')
3 files changed, 12 insertions, 13 deletions
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 63224d1ee8dd..89e238b001de 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -123,13 +123,18 @@ void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u1
ieee80211_tx_skb(sdata, skb, 0);
-static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
- enum ieee80211_back_parties initiator)
+int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
+ enum ieee80211_back_parties initiator)
struct ieee80211_local *local = sta->local;
int ret;
u8 *state;
+#ifdef CONFIG_MAC80211_HT_DEBUG
+ printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
+ sta->sta.addr, tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
state = &sta->ampdu_mlme.tid_state_tx[tid];
@@ -143,7 +148,6 @@ static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
/* HW shall not deny going back to legacy */
if (WARN_ON(ret)) {
* We may have pending packets get stuck in this case...
* Not bothering with a workaround for now.
@@ -525,11 +529,6 @@ int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
goto unlock;
-#ifdef CONFIG_MAC80211_HT_DEBUG
- printk(KERN_DEBUG "Tx BA session stop requested for %pM tid %u\n",
- sta->sta.addr, tid);
-#endif /* CONFIG_MAC80211_HT_DEBUG */
ret = ___ieee80211_stop_tx_ba_session(sta, tid, initiator);
diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index 48ef1a282b91..cdc58e61d921 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c
@@ -141,7 +141,6 @@ void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_mgmt *mgmt, size_t len)
- struct ieee80211_local *local = sdata->local;
u16 tid, params;
u16 initiator;
@@ -161,10 +160,9 @@ void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
- sta->ampdu_mlme.tid_state_tx[tid] =
+ if (sta->ampdu_mlme.tid_state_tx[tid] & HT_ADDBA_REQUESTED_MSK)
+ ___ieee80211_stop_tx_ba_session(sta, tid,
- ieee80211_stop_tx_ba_session(&local->hw, sta->sta.addr, tid,
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a910bf1f092f..10d316e455de 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1091,6 +1091,8 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
enum ieee80211_back_parties initiator);
+int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
+ enum ieee80211_back_parties initiator);
/* Spectrum management */
void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,