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

From: Shuah Khan
Date: Thu Dec 07 2017 - 16:19:17 EST


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 <shuahkh@xxxxxxxxxxxxxxx>
---
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