diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2014-03-27 12:00:26 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-03-28 16:07:31 -0400 |
| commit | d8316f3991d207fe32881a9ac20241be8fa2bad0 (patch) | |
| tree | 76802d9368e0115d9c53ac7cf0477b53011a4486 /drivers/vhost/net.c | |
| parent | 05efa8c943b1d5d90fa8c8147571837573338bb6 (diff) | |
| download | lwn-d8316f3991d207fe32881a9ac20241be8fa2bad0.tar.gz lwn-d8316f3991d207fe32881a9ac20241be8fa2bad0.zip | |
vhost: fix total length when packets are too short
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>
Diffstat (limited to 'drivers/vhost/net.c')
| -rw-r--r-- | drivers/vhost/net.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index a0fa5de210cf..026be580d318 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -532,6 +532,12 @@ 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); @@ -587,6 +593,14 @@ 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))) { |