When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky.

Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().

Cc: stable@vger.kernel.org Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") Signed-off-by: Will Deacon will@kernel.org --- net/vmw_vsock/virtio_transport.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index f0e48e6911fc..bd2c6aaa1a93 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -624,8 +624,9 @@ static void virtio_transport_rx_work(struct work_struct *work) do { virtqueue_disable_cb(vq); for (;;) { + unsigned int len, payload_len; + struct virtio_vsock_hdr *hdr; struct sk_buff *skb; - unsigned int len;

if (!virtio_transport_more_replies(vsock)) { /* Stop rx until the device processes already @@ -642,12 +643,19 @@ static void virtio_transport_rx_work(struct work_struct *work) vsock->rx_buf_nr--;

/* Drop short/long packets */ - if (unlikely(len < sizeof(struct virtio_vsock_hdr) || + if (unlikely(len < sizeof(*hdr) || len > virtio_vsock_skb_len(skb))) { kfree_skb(skb); continue; }

+ hdr = virtio_vsock_hdr(skb); + payload_len = le32_to_cpu(hdr->len); + if (payload_len > len - sizeof(*hdr)) { + kfree_skb(skb); + continue; + } + virtio_vsock_skb_rx_put(skb); virtio_transport_deliver_tap_pkt(skb); virtio_transport_recv_pkt(&virtio_transport, skb);