[PATCH net 2/2] vsock/virtio: add WARN_ON check on virtio_transport_get_ops()

From: Stefano Garzarella
Date: Fri Dec 13 2019 - 13:48:38 EST


virtio_transport_get_ops() and virtio_transport_send_pkt_info()
can only be used on connecting/connected sockets, since a socket
assigned to a transport is required.

This patch adds a WARN_ON() on virtio_transport_get_ops() to check
this requirement, a comment and a returned error on
virtio_transport_send_pkt_info(),

Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
net/vmw_vsock/virtio_transport_common.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index f5991006190e..6abec3fc81d1 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -34,6 +34,9 @@ virtio_transport_get_ops(struct vsock_sock *vsk)
{
const struct vsock_transport *t = vsock_core_get_transport(vsk);

+ if (WARN_ON(!t))
+ return NULL;
+
return container_of(t, struct virtio_transport, transport);
}

@@ -161,15 +164,25 @@ void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
}
EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);

+/* This function can only be used on connecting/connected sockets,
+ * since a socket assigned to a transport is required.
+ *
+ * Do not use on listener sockets!
+ */
static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
struct virtio_vsock_pkt_info *info)
{
u32 src_cid, src_port, dst_cid, dst_port;
+ const struct virtio_transport *t_ops;
struct virtio_vsock_sock *vvs;
struct virtio_vsock_pkt *pkt;
u32 pkt_len = info->pkt_len;

- src_cid = virtio_transport_get_ops(vsk)->transport.get_local_cid();
+ t_ops = virtio_transport_get_ops(vsk);
+ if (unlikely(!t_ops))
+ return -EFAULT;
+
+ src_cid = t_ops->transport.get_local_cid();
src_port = vsk->local_addr.svm_port;
if (!info->remote_cid) {
dst_cid = vsk->remote_addr.svm_cid;
@@ -202,7 +215,7 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,

virtio_transport_inc_tx_pkt(vvs, pkt);

- return virtio_transport_get_ops(vsk)->send_pkt(pkt);
+ return t_ops->send_pkt(pkt);
}

static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
--
2.23.0