UPSTREAM: 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: Kuen-Han Tsai <khtsai@google.com>
Message-ID: <20230602070009.1353946-1-khtsai@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 283247551
Bug: 301257472
Bug: 308355601
(cherry picked from commit ffd603f214237e250271162a5b325c6199a65382)
Change-Id: I782ef328b0d49810d3fb23c002a86439e6728542
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
(cherry picked from commit ca0cd377615866a0253c6e495f99fad57bbaab86)
(cherry picked from commit 2a75568a6b9d1a9bfcaa4298485d9e662732454e)
(cherry picked from commit 3c5c00dc8f42af0d829a087155b14da307560cdb)
diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 948eabf..a2c8499 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -538,16 +538,20 @@
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)
