Commit 1c3d185a authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: fix tid_agg_rx NULL dereference 



On drivers setting the SUPPORTS_REORDERING_BUFFER hardware flag,
we crash when the peer sends an AddBA request while we already
have a session open on the seame TID; this is because on those
drivers, the tid_agg_rx is left NULL even though the session is
valid, and the agg_session_valid bit is set.

To fix this, store the dialog tokens outside the tid_agg_rx to
be able to compare them to the received AddBA request.

Fixes: f89e07d4 ("mac80211: agg-rx: refuse ADDBA Request with timeout update")
Reported-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent a1264c3d

net/mac80211/agg-rx.c

+2 −6
Original line number Diff line number Diff line
@@ -315,11 +315,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, 
	mutex_lock(&sta->ampdu_mlme.mtx);



	if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {

		tid_agg_rx = rcu_dereference_protected(

				sta->ampdu_mlme.tid_rx[tid],

				lockdep_is_held(&sta->ampdu_mlme.mtx));



		if (tid_agg_rx->dialog_token == dialog_token) {

		if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {

			ht_dbg_ratelimited(sta->sdata,

					   "updated AddBA Req from %pM on tid %u\n",

					   sta->sta.addr, tid);
@@ -396,7 +392,6 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, 
	}



	/* update data */

	tid_agg_rx->dialog_token = dialog_token;

	tid_agg_rx->ssn = start_seq_num;

	tid_agg_rx->head_seq_num = start_seq_num;

	tid_agg_rx->buf_size = buf_size;
@@ -418,6 +413,7 @@ end: 
	if (status == WLAN_STATUS_SUCCESS) {

		__set_bit(tid, sta->ampdu_mlme.agg_session_valid);

		__clear_bit(tid, sta->ampdu_mlme.unexpected_agg);

		sta->ampdu_mlme.tid_rx_token[tid] = dialog_token;

	}

	mutex_unlock(&sta->ampdu_mlme.mtx);

net/mac80211/debugfs_sta.c

+1 −1
Original line number Diff line number Diff line
@@ -205,7 +205,7 @@ static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf, 
		p += scnprintf(p, sizeof(buf) + buf - p, "%02d", i);

		p += scnprintf(p, sizeof(buf) + buf - p, "\t\t%x", !!tid_rx);

		p += scnprintf(p, sizeof(buf) + buf - p, "\t%#.2x",

				tid_rx ? tid_rx->dialog_token : 0);

				tid_rx ? sta->ampdu_mlme.tid_rx_token[i] : 0);

		p += scnprintf(p, sizeof(buf) + buf - p, "\t%#.3x",

				tid_rx ? tid_rx->ssn : 0);

net/mac80211/sta_info.h

+2 −2
Original line number Diff line number Diff line
@@ -184,7 +184,6 @@ struct tid_ampdu_tx { 
 * @ssn: Starting Sequence Number expected to be aggregated.

 * @buf_size: buffer size for incoming A-MPDUs

 * @timeout: reset timer value (in TUs).

 * @dialog_token: dialog token for aggregation session

 * @rcu_head: RCU head used for freeing this struct

 * @reorder_lock: serializes access to reorder buffer, see below.

 * @auto_seq: used for offloaded BA sessions to automatically pick head_seq_and
@@ -213,7 +212,6 @@ struct tid_ampdu_rx { 
	u16 ssn;

	u16 buf_size;

	u16 timeout;

	u8 dialog_token;

	bool auto_seq;

	bool removed;

};
@@ -225,6 +223,7 @@ struct tid_ampdu_rx { 
 *	to tid_tx[idx], which are protected by the sta spinlock)

 *	tid_start_tx is also protected by sta->lock.

 * @tid_rx: aggregation info for Rx per TID -- RCU protected

 * @tid_rx_token: dialog tokens for valid aggregation sessions

 * @tid_rx_timer_expired: bitmap indicating on which TIDs the

 *	RX timer expired until the work for it runs

 * @tid_rx_stop_requested:  bitmap indicating which BA sessions per TID the
@@ -243,6 +242,7 @@ struct sta_ampdu_mlme { 
	struct mutex mtx;

	/* rx */

	struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];

	u8 tid_rx_token[IEEE80211_NUM_TIDS];

	unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];

	unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];

	unsigned long agg_session_valid[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];

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