Commit b348d7dd authored Mar 17, 2016 by Ignat Korchagin Committed by Greg Kroah-Hartman Mar 30, 2016

USB: usbip: fix potential out-of-bounds write

Fix potential out-of-bounds write to urb->transfer_buffer
usbip handles network communication directly in the kernel. When receiving a
packet from its peer, usbip code parses headers according to protocol. As
part of this parsing urb->actual_length is filled. Since the input for
urb->actual_length comes from the network, it should be treated as untrusted.
Any entity controlling the network may put any value in the input and the
preallocated urb->transfer_buffer may not be large enough to hold the data.
Thus, the malicious entity is able to write arbitrary data to kernel memory.

Signed-off-by: Ignat Korchagin <ignat.korchagin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 8ef34aa5

drivers/usb/usbip/usbip_common.c

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device ud, struct urb urb)
	if (!(size > 0))		if (!(size > 0))
	return 0;		return 0;

			if (size > urb->transfer_buffer_length) {
			/* should not happen, probably malicious packet */
			if (ud->side == USBIP_STUB) {
			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
			return 0;
			} else {
			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
			return -EPIPE;
			}
			}

	ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);		ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
	if (ret != size) {		if (ret != size) {
	dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);