linux-stable.git/drivers/vhost, branch v4.14.166

vhost/vsock: accept only packets with the right dst_cid

2020-01-04T13:00:14+00:00

[ Upstream commit 8a3cc29c316c17de590e3ff8b59f3d6cbfd37b0a ]

When we receive a new packet from the guest, we check if the
src_cid is correct, but we forgot to check the dst_cid.

The host should accept only packets where dst_cid is
equal to the host CID.

Signed-off-by: Stefano Garzarella 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

vhost/vsock: split packets to send using multiple buffers

2019-12-01T08:13:11+00:00

commit 6dbd3e66e7785a2f055bf84d98de9b8fd31ff3f5 upstream.

If the packets to sent to the guest are bigger than the buffer
available, we can split them, using multiple buffers and fixing
the length in the packet header.
This is safe since virtio-vsock supports only stream sockets.

Signed-off-by: Stefano Garzarella 
Reviewed-by: Stefan Hajnoczi 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

vhost: make sure log_num < in_num

2019-09-16T06:20:46+00:00

commit 060423bfdee3f8bc6e2c1bac97de24d5415e2bc4 upstream.

The code assumes log_num < in_num everywhere, and that is true as long as
in_num is incremented by descriptor iov count, and log_num by 1. However
this breaks if there's a zero sized descriptor.

As a result, if a malicious guest creates a vring desc with desc.len = 0,
it may cause the host kernel to crash by overflowing the log array. This
bug can be triggered during the VM migration.

There's no need to log when desc.len = 0, so just don't increment log_num
in this case.

Fixes: 3a4d5c94e959 ("vhost_net: a kernel-level virtio server")
Cc: stable@vger.kernel.org
Reviewed-by: Lidong Chen 
Signed-off-by: ruippan 
Signed-off-by: yongduan 
Acked-by: Michael S. Tsirkin 
Reviewed-by: Tyler Hicks 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Greg Kroah-Hartman

vhost/test: fix build for vhost test

2019-09-16T06:20:45+00:00

commit 264b563b8675771834419057cbe076c1a41fb666 upstream.

Since vhost_exceeds_weight() was introduced, callers need to specify
the packet weight and byte weight in vhost_dev_init(). Note that, the
packet weight isn't counted in this patch to keep the original behavior
unchanged.

Fixes: e82b9b0727ff ("vhost: introduce vhost_exceeds_weight()")
Cc: stable@vger.kernel.org
Signed-off-by: Tiwei Bie 
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Signed-off-by: Greg Kroah-Hartman

vhost_net: disable zerocopy by default

2019-07-31T05:28:26+00:00

[ Upstream commit 098eadce3c622c07b328d0a43dda379b38cf7c5e ]

Vhost_net was known to suffer from HOL[1] issues which is not easy to
fix. Several downstream disable the feature by default. What's more,
the datapath was split and datacopy path got the support of batching
and XDP support recently which makes it faster than zerocopy part for
small packets transmission.

It looks to me that disable zerocopy by default is more
appropriate. It cold be enabled by default again in the future if we
fix the above issues.

[1] https://patchwork.kernel.org/patch/3787671/

Signed-off-by: Jason Wang 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

vhost: scsi: add weight support

2019-07-10T07:54:42+00:00

commit c1ea02f15ab5efb3e93fc3144d895410bf79fcf2 upstream.

This patch will check the weight and exit the loop if we exceeds the
weight. This is useful for preventing scsi kthread from hogging cpu
which is guest triggerable.

This addresses CVE-2019-3900.

Cc: Paolo Bonzini 
Cc: Stefan Hajnoczi 
Fixes: 057cbf49a1f0 ("tcm_vhost: Initial merge for vhost level target fabric driver")
Signed-off-by: Jason Wang 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

vhost: vsock: add weight support

2019-07-10T07:54:42+00:00

commit e79b431fb901ba1106670bcc80b9b617b25def7d upstream.

This patch will check the weight and exit the loop if we exceeds the
weight. This is useful for preventing vsock kthread from hogging cpu
which is guest triggerable. The weight can help to avoid starving the
request from on direction while another direction is being processed.

The value of weight is picked from vhost-net.

This addresses CVE-2019-3900.

Cc: Stefan Hajnoczi 
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko")
Signed-off-by: Jason Wang 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

vhost_net: fix possible infinite loop

2019-07-10T07:54:42+00:00

commit e2412c07f8f3040593dfb88207865a3cd58680c0 upstream.

When the rx buffer is too small for a packet, we will discard the vq
descriptor and retry it for the next packet:

while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
					      &busyloop_intr))) {
...
	/* On overrun, truncate and discard */
	if (unlikely(headcount > UIO_MAXIOV)) {
		iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
		err = sock->ops->recvmsg(sock, &msg,
					 1, MSG_DONTWAIT | MSG_TRUNC);
		pr_debug("Discarded rx packet: len %zd\n", sock_len);
		continue;
	}
...
}

This makes it possible to trigger a infinite while..continue loop
through the co-opreation of two VMs like:

1) Malicious VM1 allocate 1 byte rx buffer and try to slow down the
   vhost process as much as possible e.g using indirect descriptors or
   other.
2) Malicious VM2 generate packets to VM1 as fast as possible

Fixing this by checking against weight at the end of RX and TX
loop. This also eliminate other similar cases when:

- userspace is consuming the packets in the meanwhile
- theoretical TOCTOU attack if guest moving avail index back and forth
  to hit the continue after vhost find guest just add new buffers

This addresses CVE-2019-3900.

Fixes: d8316f3991d20 ("vhost: fix total length when packets are too short")
Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
Signed-off-by: Jason Wang 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Balbir Singh

vhost: introduce vhost_exceeds_weight()

2019-07-10T07:54:42+00:00

commit e82b9b0727ff6d665fff2d326162b460dded554d upstream.

We used to have vhost_exceeds_weight() for vhost-net to:

- prevent vhost kthread from hogging the cpu
- balance the time spent between TX and RX

This function could be useful for vsock and scsi as well. So move it
to vhost.c. Device must specify a weight which counts the number of
requests, or it can also specific a byte_weight which counts the
number of bytes that has been processed.

Signed-off-by: Jason Wang 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

vhost_net: introduce vhost_exceeds_weight()

2019-07-10T07:54:41+00:00

commit 272f35cba53d088085e5952fd81d7a133ab90789 upstream.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman