vhost: fix potential fd leak

Vhost will create temporary file when receiving VHOST_USER_GET_INFLIGHT_FD
message. Malicious guest can send endless this message to drain out the
resource of host.

When receiving VHOST_USER_GET_INFLIGHT_FD message repeatedly, closing the
file created during the last handling of this message.

CVE-2020-10726
Fixes: d87f1a1cb7b666550 ("vhost: support inflight info sharing")
Cc: stable@dpdk.org
Signed-off-by: Xuan Ding <xuan.ding@intel.com>
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 9d25490..84bebad 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -206,7 +206,7 @@ vhost_backend_cleanup(struct virtio_net *dev)
                        dev->inflight_info->addr = NULL;
                }
 
-               if (dev->inflight_info->fd > 0) {
+               if (dev->inflight_info->fd >= 0) {
                        close(dev->inflight_info->fd);
                        dev->inflight_info->fd = -1;
                }
@@ -1417,6 +1417,7 @@ vhost_user_get_inflight_fd(struct virtio_net **pdev,
                                "failed to alloc dev inflight area\n");
                        return RTE_VHOST_MSG_RESULT_ERR;
                }
+               dev->inflight_info->fd = -1;
        }
 
        num_queues = msg->payload.inflight.num_queues;
@@ -1447,6 +1448,11 @@ vhost_user_get_inflight_fd(struct virtio_net **pdev,
                dev->inflight_info->addr = NULL;
        }
 
+       if (dev->inflight_info->fd >= 0) {
+               close(dev->inflight_info->fd);
+               dev->inflight_info->fd = -1;
+       }
+
        dev->inflight_info->addr = addr;
        dev->inflight_info->size = msg->payload.inflight.mmap_size = mmap_size;
        dev->inflight_info->fd = msg->fds[0] = fd;
@@ -1529,6 +1535,7 @@ vhost_user_set_inflight_fd(struct virtio_net **pdev, VhostUserMsg *msg,
                                "failed to alloc dev inflight area\n");
                        return RTE_VHOST_MSG_RESULT_ERR;
                }
+               dev->inflight_info->fd = -1;
        }
 
        if (dev->inflight_info->addr) {
@@ -1543,8 +1550,10 @@ vhost_user_set_inflight_fd(struct virtio_net **pdev, VhostUserMsg *msg,
                return RTE_VHOST_MSG_RESULT_ERR;
        }
 
-       if (dev->inflight_info->fd)
+       if (dev->inflight_info->fd >= 0) {
                close(dev->inflight_info->fd);
+               dev->inflight_info->fd = -1;
+       }
 
        dev->inflight_info->fd = fd;
        dev->inflight_info->addr = addr;