Commit 6a2c0962 authored by Stefano Garzarella's avatar Stefano Garzarella Committed by David S. Miller
Browse files

vsock: prevent transport modules unloading 



This patch adds 'module' member in the 'struct vsock_transport'
in order to get/put the transport module. This prevents the
module unloading while sockets are assigned to it.

We increase the module refcnt when a socket is assigned to a
transport, and we decrease the module refcnt when the socket
is destructed.

Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarJorgen Hansen <jhansen@vmware.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b1bba80a

drivers/vhost/vsock.c

+2 −0
Original line number Diff line number Diff line
@@ -386,6 +386,8 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) 


static struct virtio_transport vhost_transport = {

	.transport = {

		.module                   = THIS_MODULE,



		.get_local_cid            = vhost_transport_get_local_cid,



		.init                     = virtio_transport_do_socket_init,

include/net/af_vsock.h

+2 −0
Original line number Diff line number Diff line
@@ -100,6 +100,8 @@ struct vsock_transport_send_notify_data { 
#define VSOCK_TRANSPORT_F_DGRAM		0x00000004



struct vsock_transport {

	struct module *module;



	/* Initialize/tear-down socket. */

	int (*init)(struct vsock_sock *, struct vsock_sock *);

	void (*destruct)(struct vsock_sock *);

net/vmw_vsock/af_vsock.c

+16 −4
Original line number Diff line number Diff line
@@ -380,6 +380,16 @@ void vsock_enqueue_accept(struct sock *listener, struct sock *connected) 
}

EXPORT_SYMBOL_GPL(vsock_enqueue_accept);



static void vsock_deassign_transport(struct vsock_sock *vsk)

{

	if (!vsk->transport)

		return;



	vsk->transport->destruct(vsk);

	module_put(vsk->transport->module);

	vsk->transport = NULL;

}



/* Assign a transport to a socket and call the .init transport callback.

 *

 * Note: for stream socket this must be called when vsk->remote_addr is set
@@ -418,10 +428,13 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) 
			return 0;



		vsk->transport->release(vsk);

		vsk->transport->destruct(vsk);

		vsock_deassign_transport(vsk);

	}



	if (!new_transport)

	/* We increase the module refcnt to prevent the transport unloading

	 * while there are open sockets assigned to it.

	 */

	if (!new_transport || !try_module_get(new_transport->module))

		return -ENODEV;



	vsk->transport = new_transport;
@@ -741,8 +754,7 @@ static void vsock_sk_destruct(struct sock *sk) 
{

	struct vsock_sock *vsk = vsock_sk(sk);



	if (vsk->transport)

		vsk->transport->destruct(vsk);

	vsock_deassign_transport(vsk);



	/* When clearing these addresses, there's no need to set the family and

	 * possibly register the address family with the kernel.

net/vmw_vsock/hyperv_transport.c

+2 −0
Original line number Diff line number Diff line
@@ -857,6 +857,8 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written, 
}



static struct vsock_transport hvs_transport = {

	.module                   = THIS_MODULE,



	.get_local_cid            = hvs_get_local_cid,



	.init                     = hvs_sock_init,

net/vmw_vsock/virtio_transport.c

+2 −0
Original line number Diff line number Diff line
@@ -462,6 +462,8 @@ static void virtio_vsock_rx_done(struct virtqueue *vq) 


static struct virtio_transport virtio_transport = {

	.transport = {

		.module                   = THIS_MODULE,



		.get_local_cid            = virtio_transport_get_local_cid,



		.init                     = virtio_transport_do_socket_init,

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