usbip: fix vudc_rx: harden CMD_SUBMIT path to handle malicious input

Harden CMD_SUBMIT path to handle malicious input that could trigger
large memory allocations. Add checks to validate transfer_buffer_length
and number_of_packets to protect against bad input requesting for
unbounded memory allocations.

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

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/usb/usbip/vudc_rx.c b/drivers/usb/usbip/vudc_rx.c
index df1e30989148..1e8a23d92cb4 100644
--- a/drivers/usb/usbip/vudc_rx.c
+++ b/drivers/usb/usbip/vudc_rx.c
@@ -120,6 +120,25 @@ static int v_recv_cmd_submit(struct vudc *udc,
         urb_p->new = 1;
         urb_p->seqnum = pdu->base.seqnum;
 
+        if (urb_p->ep->type == USB_ENDPOINT_XFER_ISOC) {
+                /* validate packet size and number of packets */
+                unsigned int maxp, packets, bytes;
+
+                maxp = usb_endpoint_maxp(urb_p->ep->desc);
+                maxp *= usb_endpoint_maxp_mult(urb_p->ep->desc);
+                bytes = pdu->u.cmd_submit.transfer_buffer_length;
+                packets = DIV_ROUND_UP(bytes, maxp);
+
+                if (pdu->u.cmd_submit.number_of_packets < 0 ||
+                    pdu->u.cmd_submit.number_of_packets > packets) {
+                        dev_err(&udc->gadget.dev,
+                                "CMD_SUBMIT: isoc invalid num packets %d\n",
+                                pdu->u.cmd_submit.number_of_packets);
+                        ret = -EMSGSIZE;
+                        goto free_urbp;
+                }
+        }
+
         ret = alloc_urb_from_cmd(&urb_p->urb, pdu, urb_p->ep->type);
         if (ret) {
                 usbip_event_add(&udc->ud, VUDC_EVENT_ERROR_MALLOC);