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

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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: Kuen-Han Tsai <khtsai@google.com>
Message-ID: <20230602070009.1353946-1-khtsai@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kuen-Han Tsai 2023-06-02 15:00:06 +08:00 committed by Greg Kroah-Hartman
parent 0a453dc9f2
commit ffd603f214
1 changed files with 5 additions and 1 deletions
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6
drivers/usb/gadget/function/u_serial.c
View file

@ -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)