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 <[email protected]> know about it.
>From foo@baz Mon Apr 14 15:32:12 PDT 2014
From: "Michael S. Tsirkin" <[email protected]>
Date: Thu, 27 Mar 2014 12:00:26 +0200
Subject: vhost: fix total length when packets are too short
From: "Michael S. Tsirkin" <[email protected]>
[ 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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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 [email protected] 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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