usbip: vudc_tx: fix v_send_ret_submit() vulnerability to null xfer buffer

commit 5fd77a3a0e408c23ab4002a57db980e46bc16e72 upstream.

v_send_ret_submit() handles urb with a null transfer_buffer, when it
replays a packet with potential malicious data that could contain a
null buffer.

Add a check for the condition when actual_length > 0 and transfer_buffer
is null.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/usbip/vudc_tx.c b/drivers/usb/usbip/vudc_tx.c
index 2346617..3ab4c86 100644 (file)
--- a/drivers/usb/usbip/vudc_tx.c
+++ b/drivers/usb/usbip/vudc_tx.c
@@ -97,6 +97,13 @@ static int v_send_ret_submit(struct vudc *udc, struct urbp *urb_p)
        memset(&pdu_header, 0, sizeof(pdu_header));
        memset(&msg, 0, sizeof(msg));
 
+       if (urb->actual_length > 0 && !urb->transfer_buffer) {
+               dev_err(&udc->gadget.dev,
+                       "urb: actual_length %d transfer_buffer null\n",
+                       urb->actual_length);
+               return -1;
+       }
+
        if (urb_p->type == USB_ENDPOINT_XFER_ISOC)
                iovnum = 2 + urb->number_of_packets;
        else
@@ -112,8 +119,8 @@ static int v_send_ret_submit(struct vudc *udc, struct urbp *urb_p)
 
        /* 1. setup usbip_header */
        setup_ret_submit_pdu(&pdu_header, urb_p);
-       usbip_dbg_stub_tx("setup txdata seqnum: %d urb: %p\n",
-                         pdu_header.base.seqnum, urb);
+       usbip_dbg_stub_tx("setup txdata seqnum: %d\n",
+                         pdu_header.base.seqnum);
        usbip_header_correct_endian(&pdu_header, 1);
 
        iov[iovnum].iov_base = &pdu_header;