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| author | Michael S. Tsirkin <mst@redhat.com> | 2014-03-27 12:00:26 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-14 06:42:18 -0700 |
| commit | f78f1512ec2a6fca1ffd98c5b95757ec62be1389 (patch) | |
| tree | 7003dbca27b640d897c772670b2a64ffdac9c05d | |
| parent | 48f77355b32ab30456a0d6fda1ee2d367b9a3d25 (diff) | |
| download | lwn-f78f1512ec2a6fca1ffd98c5b95757ec62be1389.tar.gz lwn-f78f1512ec2a6fca1ffd98c5b95757ec62be1389.zip | |
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 d6a518ce4d6d..262842fd6635 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -540,6 +540,12 @@ 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); @@ -595,6 +601,14 @@ 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))) { |