@@ -462,6 +462,12 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
*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);
@@ -516,6 +522,14 @@ static void handle_rx(struct vhost_net *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))) {
This is a note to let you know that I have just added a patch titled vhost: fix total length when packets are too short to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.22. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From f936659d48b1ade14510df2b3c8ef19086578483 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" <mst@redhat.com> Date: Thu, 27 Mar 2014 12:00:26 +0200 Subject: vhost: fix total length when packets are too short [ 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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/vhost/net.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) -- 1.8.3.2