Commit ffd603f2 authored by Kuen-Han Tsai's avatar Kuen-Han Tsai Committed by Greg Kroah-Hartman
Browse files

usb: gadget: u_serial: Add null pointer check in gs_start_io 



If gs_close has cleared port->port.tty and gs_start_io is called
afterwards, then the function tty_wakeup will attempt to access the value
of the pointer port->port.tty which will cause a null pointer
dereference error.

To avoid this, add a null pointer check to gs_start_io before attempting
to access the value of the pointer port->port.tty.

Signed-off-by: default avatarKuen-Han Tsai <khtsai@google.com>
Message-ID: <20230602070009.1353946-1-khtsai@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0a453dc9

drivers/usb/gadget/function/u_serial.c

+5 −1
Original line number Diff line number Diff line
@@ -539,16 +539,20 @@ static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, 
static int gs_start_io(struct gs_port *port)

{

	struct list_head	*head = &port->read_pool;

	struct usb_ep		*ep = port->port_usb->out;

	struct usb_ep		*ep;

	int			status;

	unsigned		started;



	if (!port->port_usb || !port->port.tty)

		return -EIO;



	/* Allocate RX and TX I/O buffers.  We can't easily do this much

	 * earlier (with GFP_KERNEL) because the requests are coupled to

	 * endpoints, as are the packet sizes we'll be using.  Different

	 * configurations may use different endpoints with a given port;

	 * and high speed vs full speed changes packet sizes too.

	 */

	ep = port->port_usb->out;

	status = gs_alloc_requests(ep, head, gs_read_complete,

		&port->read_allocated);

	if (status)