Patch "USB: usbip: fix potential out-of-bounds write" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-usbip-fix-potential-out-of-bounds-write.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ignat Korchagin <[email protected]>
Date: Thu, 17 Mar 2016 18:00:29 +0000
Subject: USB: usbip: fix potential out-of-bounds write

From: Ignat Korchagin <[email protected]>

commit b348d7dddb6c4fbfc810b7a0626e8ec9e29f7cbb upstream.

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.

---
 drivers/usb/usbip/usbip_common.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

@@ -741,6 +741,17 @@ int usbip_recv_xbuff(struct usbip_device
 	if (!(size > 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);
 	if (ret != size) {
 		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/usb-usbip-fix-potential-out-of-bounds-write.patch