[PATCH] Bluetooth: btintel_pcie: Fix array bounds check bugs

[ZhaoJinming]

Fix four array bounds issues in the Intel BT PCIe driver:

1. btintel_pcie_send_sync(): bounds check for tfd_index uses '>' instead
   of '>='.  When tfd_index == txq->count (32), the check passes and
   btintel_pcie_prepare_tx() writes past the end of txq->tfds[] and
   txq->bufs[].

2. btintel_pcie_submit_rx(): same off-by-one on frbd_index.  When
   frbd_index == rxq->count (64), the check passes and
   btintel_pcie_prepare_rx() writes past the end of rxq->frbds[] and
   rxq->bufs[].

3. btintel_pcie_msix_tx_handle(): cr_tia (device-controlled, from
   shared DMA memory) is used to index txq->urbd0s[] before any bounds
   check, and the urbd0->tfd_index check uses '>' instead of '>='.

4. btintel_pcie_msix_rx_handle(): cr_tia (device-controlled) indexes
   rxq->urbd1s[] with no bounds check.  urbd1->frbd_tag is a 16-bit
   device-controlled field (0-65535) used directly as an index into
   rxq->bufs[] (64 elements).

Fix all four by correcting the comparison operators and adding explicit
bounds checks on device-controlled indices before array access.

Fixes: c2b636b3f788 ("Bluetooth: btintel_pcie: Add support for PCIe transport")
Signed-off-by: ZhaoJinming <zhaojinming@xxxxxxxxxxxxx>
---
 drivers/bluetooth/btintel_pcie.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 2b7231be5973..32cfa0f5af1c 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -401,7 +401,7 @@ static int btintel_pcie_send_sync(struct btintel_pcie_data *data,
 
 	tfd_index = data->ia.tr_hia[BTINTEL_PCIE_TXQ_NUM];
 
-	if (tfd_index > txq->count)
+	if (tfd_index >= txq->count)
 		return -ERANGE;
 
 	/* Firmware raises alive interrupt on HCI_OP_RESET or
@@ -502,7 +502,7 @@ static int btintel_pcie_submit_rx(struct btintel_pcie_data *data)
 
 	frbd_index = data->ia.tr_hia[BTINTEL_PCIE_RXQ_NUM];
 
-	if (frbd_index > rxq->count)
+	if (frbd_index >= rxq->count)
 		return -ERANGE;
 
 	/* Prepare for RX submit. It updates the FRBD with the address of DMA
@@ -1094,12 +1094,15 @@ static void btintel_pcie_msix_tx_handle(struct btintel_pcie_data *data)
 	txq = &data->txq;
 
 	while (cr_tia != cr_hia) {
+		if (cr_tia >= txq->count)
+			return;
+
 		data->tx_wait_done = true;
 		wake_up(&data->tx_wait_q);
 
 		urbd0 = &txq->urbd0s[cr_tia];
 
-		if (urbd0->tfd_index > txq->count)
+		if (urbd0->tfd_index >= txq->count)
 			return;
 
 		cr_tia = (cr_tia + 1) % txq->count;
@@ -1584,9 +1587,21 @@ static void btintel_pcie_msix_rx_handle(struct btintel_pcie_data *data)
 	 * process all received CDs in this interrupt.
 	 */
 	while (cr_tia != cr_hia) {
+		if (cr_tia >= rxq->count) {
+			bt_dev_err(hdev, "RXQ: invalid cr_tia %u (count %u)",
+				   cr_tia, rxq->count);
+			return;
+		}
+
 		urbd1 = &rxq->urbd1s[cr_tia];
 		ipc_print_urbd1(data->hdev, urbd1, cr_tia);
 
+		if (urbd1->frbd_tag >= rxq->count) {
+			bt_dev_err(hdev, "RXQ: invalid frbd_tag %u (count %u)",
+				   urbd1->frbd_tag, rxq->count);
+			return;
+		}
+
 		buf = &rxq->bufs[urbd1->frbd_tag];
 		if (!buf) {
 			bt_dev_err(hdev, "RXQ: failed to get the DMA buffer for %d",

base-commit: 3d6d817622b0a9721e3cc404df3469171582be13
-- 
2.51.0