[PATCH 1/4] usbip: fix stub_rx: get_pipe() to validate endpoint number

[Shuah Khan]

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.

Signed-off-by: Shuah Khan <shua...@osg.samsung.com>
---
 drivers/usb/usbip/stub_rx.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index 536e037f541f..4d61063c259d 100644
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -328,15 +328,15 @@ 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)) {
@@ -367,9 +367,10 @@ 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)
@@ -435,6 +436,9 @@ 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;
-- 
2.14.1

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