[PATCH 3.2 73/79] usbip: fix stub_rx: get_pipe() to validate endpoint number

Ben Hutchings
2018-02-11T04:33:41Z

From: Shuah Khan <shuahkh@osg.samsung.com>

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>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/staging/usbip/stub_rx.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

--- a/drivers/staging/usbip/stub_rx.c
+++ b/drivers/staging/usbip/stub_rx.c
@@ -356,15 +356,15 @@ static int get_pipe(struct stub_device *
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->interface->dev, "no such endpoint?, %d\n",
- epnum);
- BUG();
- }
+ if (!ep)
+ goto err_ret;

epd = &ep->desc;
if (usb_endpoint_xfer_control(epd)) {
@@ -395,9 +395,10 @@ static int get_pipe(struct stub_device *
return usb_rcvisocpipe(udev, epnum);
}

+err_ret:
/* NOT REACHED */
- dev_err(&sdev->interface->dev, "get pipe, epnum %d\n", epnum);
- return 0;
+ dev_err(&sdev->interface->dev, "get pipe() invalid epnum %d\n", epnum);
+ return -1;
}

static void masking_bogus_flags(struct urb *urb)
@@ -463,6 +464,9 @@ static void stub_recv_cmd_submit(struct
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;