Patch "vhost: fix total length when packets are too short" has been added to the 3.4-stable tree

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

    vhost: fix total length when packets are too short

to the 3.4-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:
     vhost-fix-total-length-when-packets-are-too-short.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From foo@baz Mon Apr 14 15:32:12 PDT 2014
From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Date: Thu, 27 Mar 2014 12:00:26 +0200
Subject: vhost: fix total length when packets are too short

From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>

[ Upstream commit d8316f3991d207fe32881a9ac20241be8fa2bad0 ]

When mergeable buffers are disabled, and the
incoming packet is too large for the rx buffer,
get_rx_bufs returns success.

This was intentional in order for make recvmsg
truncate the packet and then handle_rx would
detect err != sock_len and drop it.

Unfortunately we pass the original sock_len to
recvmsg - which means we use parts of iov not fully
validated.

Fix this up by detecting this overrun and doing packet drop
immediately.

CVE-2014-0077

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/vhost/net.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -351,6 +351,12 @@ static int get_rx_bufs(struct vhost_virt
 	*iovcount = seg;
 	if (unlikely(log))
 		*log_num = nlogs;
+
+	/* Detect overrun */
+	if (unlikely(datalen > 0)) {
+		r = UIO_MAXIOV + 1;
+		goto err;
+	}
 	return headcount;
 err:
 	vhost_discard_vq_desc(vq, headcount);
@@ -405,6 +411,14 @@ static void handle_rx(struct vhost_net *
 		/* On error, stop handling until the next kick. */
 		if (unlikely(headcount < 0))
 			break;
+		/* On overrun, truncate and discard */
+		if (unlikely(headcount > UIO_MAXIOV)) {
+			msg.msg_iovlen = 1;
+			err = sock->ops->recvmsg(NULL, sock, &msg,
+						 1, MSG_DONTWAIT | MSG_TRUNC);
+			pr_debug("Discarded rx packet: len %zd\n", sock_len);
+			continue;
+		}
 		/* OK, now we need to know about added descriptors. */
 		if (!headcount) {
 			if (unlikely(vhost_enable_notify(&net->dev, vq))) {


Patches currently in stable-queue which might be from mst@xxxxxxxxxx are

queue-3.4/vhost-fix-total-length-when-packets-are-too-short.patch
queue-3.4/vhost-validate-vhost_get_vq_desc-return-value.patch
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