Merge v7.0.11linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 40 insertions, 8 deletions

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 275ea865bc29..47f4902b40b4 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -194,7 +194,15 @@ void hci_uart_init_work(struct work_struct *work)
 	err = hci_register_dev(hu->hdev);
 	if (err < 0) {
 		BT_ERR("Can't register HCI device");
+
+		percpu_down_write(&hu->proto_lock);
 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
+		percpu_up_write(&hu->proto_lock);
+
+		/* Safely cancel work after clearing flags */
+		cancel_work_sync(&hu->write_work);
+
+		/* Close protocol before freeing hdev */
 		hu->proto->close(hu);
 		hdev = hu->hdev;
 		hu->hdev = NULL;
@@ -263,8 +271,12 @@ static int hci_uart_open(struct hci_dev *hdev)
 /* Close device */
 static int hci_uart_close(struct hci_dev *hdev)
 {
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+
 	BT_DBG("hdev %p", hdev);
 
+	cancel_work_sync(&hu->write_work);
+
 	hci_uart_flush(hdev);
 	hdev->flush = NULL;
 	return 0;
@@ -531,6 +543,7 @@ static void hci_uart_tty_close(struct tty_struct *tty)
 {
 	struct hci_uart *hu = tty->disc_data;
 	struct hci_dev *hdev;
+	bool proto_ready;
 
 	BT_DBG("tty %p", tty);
 
@@ -540,24 +553,38 @@ static void hci_uart_tty_close(struct tty_struct *tty)
 	if (!hu)
 		return;
 
-	hdev = hu->hdev;
-	if (hdev)
-		hci_uart_close(hdev);
+	/* Wait for init_ready to finish to prevent registration races */
+	cancel_work_sync(&hu->init_ready);
 
-	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+	proto_ready = test_bit(HCI_UART_PROTO_READY, &hu->flags);
+	if (proto_ready) {
 		percpu_down_write(&hu->proto_lock);
 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 		percpu_up_write(&hu->proto_lock);
+	}
 
-		cancel_work_sync(&hu->init_ready);
-		cancel_work_sync(&hu->write_work);
+	/*
+	 * Unconditionally cancel write_work AFTER clearing PROTO_READY.
+	 * This ensures that concurrent protocol timers cannot requeue
+	 * write_work via hci_uart_tx_wakeup(), permanently preventing
+	 * double-free races and UAFs.
+	 */
+	cancel_work_sync(&hu->write_work);
+
+	hdev = hu->hdev;
+	if (hdev)
+		hci_uart_close(hdev); /* proto->flush is safely skipped */
 
+	if (proto_ready) {
 		if (hdev) {
 			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
 				hci_unregister_dev(hdev);
-			hci_free_dev(hdev);
 		}
+		/* Close protocol before freeing hdev (intrinsically purges queues) */
 		hu->proto->close(hu);
+
+		if (hdev)
+			hci_free_dev(hdev);
 	}
 	clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 
@@ -625,11 +652,12 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
 	 * tty caller
 	 */
 	hu->proto->recv(hu, data, count);
-	percpu_up_read(&hu->proto_lock);
 
 	if (hu->hdev)
 		hu->hdev->stat.byte_rx += count;
 
+	percpu_up_read(&hu->proto_lock);
+
 	tty_unthrottle(tty);
 }
 
@@ -695,6 +723,10 @@ static int hci_uart_register_dev(struct hci_uart *hu)
 		percpu_down_write(&hu->proto_lock);
 		clear_bit(HCI_UART_PROTO_INIT, &hu->flags);
 		percpu_up_write(&hu->proto_lock);
+		/* Cancel work after clearing flags */
+		cancel_work_sync(&hu->write_work);
+
+		/* Close protocol before freeing hdev */
 		hu->proto->close(hu);
 		hu->hdev = NULL;
 		hci_free_dev(hdev);