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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stefano Garzarella 2019-11-14 10:57:48 +01:00 committed by David S. Miller
parent b1bba80a43
commit 6a2c096210
6 changed files with 25 additions and 4 deletions

View File

@ -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,

View File

@ -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 *);

View File

@ -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.

View File

@ -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,

View File

@ -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,

View File

@ -2020,6 +2020,7 @@ static u32 vmci_transport_get_local_cid(void)
}
static struct vsock_transport vmci_transport = {
.module = THIS_MODULE,
.init = vmci_transport_socket_init,
.destruct = vmci_transport_destruct,
.release = vmci_transport_release,