usbip: fix stub_rx: get_pipe() to validate endpoint number

commit 635f545a7e8be7596b9b2b6a43cab6bbd5a88e43 upstream.

get_pipe() routine doesn't validate the input endpoint number
and uses to reference ep_in and ep_out arrays. Invalid endpoint
number can trigger BUG(). Range check the epnum and returning
error instead of calling BUG().

Change caller stub_recv_cmd_submit() to handle the get_pipe()
error return.

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

diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index 191b176ffedfdaa119df7f4d31b8941e388b2299..4f03c611c16d2c1264fa2c3e965ea81945add2c8 100644 (file)
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -342,15 +342,15 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
        struct usb_host_endpoint *ep;
        struct usb_endpoint_descriptor *epd = NULL;
 
+       if (epnum < 0 || epnum > 15)
+               goto err_ret;
+
        if (dir == USBIP_DIR_IN)
                ep = udev->ep_in[epnum & 0x7f];
        else
                ep = udev->ep_out[epnum & 0x7f];
-       if (!ep) {
-               dev_err(&sdev->udev->dev, "no such endpoint?, %d\n",
-                       epnum);
-               BUG();
-       }
+       if (!ep)
+               goto err_ret;
 
        epd = &ep->desc;
        if (usb_endpoint_xfer_control(epd)) {
@@ -381,9 +381,10 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
                        return usb_rcvisocpipe(udev, epnum);
        }
 
+err_ret:
        /* NOT REACHED */
-       dev_err(&sdev->udev->dev, "get pipe, epnum %d\n", epnum);
-       return 0;
+       dev_err(&sdev->udev->dev, "get pipe() invalid epnum %d\n", epnum);
+       return -1;
 }
 
 static void masking_bogus_flags(struct urb *urb)
@@ -449,6 +450,9 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
        struct usb_device *udev = sdev->udev;
        int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction);
 
+       if (pipe == -1)
+               return;
+
        priv = stub_priv_alloc(sdev, pdu);
        if (!priv)
                return;