[PATCH] Bluetooth: btintel_pcie: validate completion ring indices

[Pengpeng Hou]

The MSI-X RX and TX completion handlers trust the shared ring indices
read from data->ia.cr_tia[] and data->ia.cr_hia[] before using cr_tia as
an index into the fixed urbd ring arrays. If the device reports a stale
or malformed completion index, the driver can step past rxq->urbd1s[] or
txq->urbd0s[] before it gets a chance to recover.

Validate both completion ring indices against the queue depth before
walking the descriptor arrays.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/bluetooth/btintel_pcie.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 37b744e35bc4..06c2b81f2b6e 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -1008,6 +1008,13 @@ static void btintel_pcie_msix_tx_handle(struct btintel_pcie_data *data)
 
 	txq = &data->txq;
 
+	if (cr_tia >= txq->count || cr_hia >= txq->count) {
+		bt_dev_err(data->hdev,
+			   "TXQ: invalid ring indices tia=%u hia=%u",
+			   cr_tia, cr_hia);
+		return;
+	}
+
 	while (cr_tia != cr_hia) {
 		data->tx_wait_done = true;
 		wake_up(&data->tx_wait_q);
@@ -1403,6 +1410,12 @@ static void btintel_pcie_msix_rx_handle(struct btintel_pcie_data *data)
 
 	rxq = &data->rxq;
 
+	if (cr_tia >= rxq->count || cr_hia >= rxq->count) {
+		bt_dev_err(hdev, "RXQ: invalid ring indices tia=%u hia=%u",
+			   cr_tia, cr_hia);
+		return;
+	}
+
 	/* The firmware sends multiple CD in a single MSI-X and it needs to
 	 * process all received CDs in this interrupt.
 	 */
-- 
2.50.1 (Apple Git-155)