[134/140] iwlagn: verify flow id in compressed BA packet

From: Greg KH
Date: Fri Jul 30 2010 - 13:38:14 EST

2.6.33-stable review patch. If anyone has any objections, please let us know.


From: Shanyu Zhao <shanyu.zhao@xxxxxxxxx>

commit b561e8274f75831ee87e4ea378cbb1f9f050a51a upstream.

The flow id (scd_flow) in a compressed BA packet should match the txq_id
of the queue from which the aggregated packets were sent. However, in
some hardware like the 1000 series, sometimes the flow id is 0 for the
txq_id (10 to 19). This can cause the annoying message:
[ 2213.306191] iwlagn 0000:01:00.0: Received BA when not expected
[ 2213.310178] iwlagn 0000:01:00.0: Read index for DMA queue txq id (0),
index 5, is out of range [0-256] 7 7.

And even worse, if agg->wait_for_ba is true when the bad BA is arriving,
this can cause system hang due to NULL pointer dereference because the
code is operating in a wrong tx queue!

Signed-off-by: Shanyu Zhao <shanyu.zhao@xxxxxxxxx>
Signed-off-by: Pradeep Kulkarni <pradeepx.kulkarni@xxxxxxxxx>
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/net/wireless/iwlwifi/iwl-tx.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/net/wireless/iwlwifi/iwl-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-tx.c
@@ -1553,6 +1553,11 @@ void iwl_rx_reply_compressed_ba(struct i
sta_id = ba_resp->sta_id;
tid = ba_resp->tid;
agg = &priv->stations[sta_id].tid[tid].agg;
+ if (unlikely(agg->txq_id != scd_flow)) {
+ IWL_ERR(priv, "BA scd_flow %d does not match txq_id %d\n",
+ scd_flow, agg->txq_id);
+ return;
+ }

/* Find index just before block-ack window */
index = iwl_queue_dec_wrap(ba_resp_scd_ssn & 0xff, txq->q.n_bd);

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