[PATCH v2] wifi: ath9k: fix OOB access from firmware tx status queue ID

[Tristan Madani <tristmd@gmail.com>]

From: Tristan Madani <tristan@talencesecurity.com>

ath_tx_edma_tasklet() accesses sc->tx.txq[ts.qid] where ts.qid is a
4-bit hardware field (0-15), but the txq array only has
ATH9K_NUM_TX_QUEUES (10) entries. A qid >= 10 causes an OOB array
access.

Add a bounds check on ts.qid before using it as an array index.

Fixes: fce041beb03f ("ath9k: unify edma and non-edma tx code, improve tx fifo handling")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
Note: v2 resubmission -- original sent via Gmail had HTML rendering
issues. This version uses git send-email for plain-text formatting.

drivers/net/wireless/ath/ath9k/xmit.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index XXXXXXX..XXXXXXX 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -2755,6 +2755,11 @@ static void ath_tx_edma_tasklet(struct ath_softc *sc)
 			continue;
 		}

+		if (ts.qid >= ATH9K_NUM_TX_QUEUES) {
+			ath_dbg(common, XMIT, "invalid qid %d\n", ts.qid);
+			continue;
+		}
+
 		txq = &sc->tx.txq[ts.qid];

 		ath_txq_lock(sc, txq);
--
2.43.0