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Commit 84cb3df0 authored by Loic Poulain's avatar Loic Poulain Committed by Marcel Holtmann
Browse files

Bluetooth: hci_ldisc: Fix null pointer derefence in case of early data 



HCI_UART_PROTO_SET flag is set before hci_uart_set_proto call. If we
receive data from tty layer during this procedure, proto pointer may
not be assigned yet, leading to null pointer dereference in rx method
hci_uart_tty_receive.

This patch fixes this issue by introducing HCI_UART_PROTO_READY flag in
order to avoid any proto operation before proto opening and assignment.

Signed-off-by: default avatarLoic Poulain <loic.poulain@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 1dbfc59a

drivers/bluetooth/hci_ldisc.c

+7 −4
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ static int hci_uart_flush(struct hci_dev *hdev) 
	tty_ldisc_flush(tty);

	tty_driver_flush_buffer(tty);



	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))

	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))

		hu->proto->flush(hu);



	return 0;
@@ -492,7 +492,7 @@ static void hci_uart_tty_close(struct tty_struct *tty) 


	cancel_work_sync(&hu->write_work);



	if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {

	if (test_and_clear_bit(HCI_UART_PROTO_READY, &hu->flags)) {

		if (hdev) {

			if (test_bit(HCI_UART_REGISTERED, &hu->flags))

				hci_unregister_dev(hdev);
@@ -500,6 +500,7 @@ static void hci_uart_tty_close(struct tty_struct *tty) 
		}

		hu->proto->close(hu);

	}

	clear_bit(HCI_UART_PROTO_SET, &hu->flags);



	kfree(hu);

}
@@ -526,7 +527,7 @@ static void hci_uart_tty_wakeup(struct tty_struct *tty) 
	if (tty != hu->tty)

		return;



	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))

	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))

		hci_uart_tx_wakeup(hu);

}
@@ -550,7 +551,7 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, 
	if (!hu || tty != hu->tty)

		return;



	if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))

	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))

		return;



	/* It does not need a lock here as it is already protected by a mutex in
@@ -638,9 +639,11 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id) 
		return err;



	hu->proto = p;

	set_bit(HCI_UART_PROTO_READY, &hu->flags);



	err = hci_uart_register_dev(hu);

	if (err) {

		clear_bit(HCI_UART_PROTO_READY, &hu->flags);

		p->close(hu);

		return err;

	}

drivers/bluetooth/hci_uart.h

+1 −0
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ struct hci_uart { 
/* HCI_UART proto flag bits */

#define HCI_UART_PROTO_SET	0

#define HCI_UART_REGISTERED	1

#define HCI_UART_PROTO_READY	2



/* TX states  */

#define HCI_UART_SENDING	1