| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <alpine.DEB.2.10.1705161358480.6833@sstabellini-ThinkPad-X260>
Date: Tue, 16 May 2017 14:02:36 -0700 (PDT)
From: Stefano Stabellini <sstabellini@...nel.org>
To: Boris Ostrovsky <boris.ostrovsky@...cle.com>
cc: Stefano Stabellini <sstabellini@...nel.org>,
xen-devel@...ts.xen.org, linux-kernel@...r.kernel.org,
jgross@...e.com, Stefano Stabellini <stefano@...reto.com>
Subject: Re: [PATCH 08/18] xen/pvcalls: implement connect command
On Mon, 15 May 2017, Boris Ostrovsky wrote:
> On 05/15/2017 04:36 PM, Stefano Stabellini wrote:
> > Allocate a socket. Keep track of socket <-> ring mappings with a new data
> > structure, called sock_mapping. Implement the connect command by calling
> > inet_stream_connect, and mapping the new indexes page and data ring.
> > Associate the socket to an ioworker randomly.
> >
> > When an active socket is closed (sk_state_change), set in_error to
> > -ENOTCONN and notify the other end, as specified by the protocol.
> >
> > sk_data_ready will be implemented later.
> >
> > Signed-off-by: Stefano Stabellini <stefano@...reto.com>
> > CC: boris.ostrovsky@...cle.com
> > CC: jgross@...e.com
> > ---
> > drivers/xen/pvcalls-back.c | 145
> > +++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 145 insertions(+)
> >
> > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> > index 2eae096..9ac1cf2 100644
> > --- a/drivers/xen/pvcalls-back.c
> > +++ b/drivers/xen/pvcalls-back.c
> > @@ -63,6 +63,29 @@ struct pvcalls_back_priv {
> > struct work_struct register_work;
> > };
> >
> > +struct sock_mapping {
> > + struct list_head list;
> > + struct list_head queue;
>
> Since you have two lists it would be helpful if names were a bit more
> descriptive.
>
> (and comments for at least some fields would be welcome too)
Yeah, you are right. list is used to add sock_mapping to
priv->socket_mappings, the per frontend list of active sockets. queue is
used to add sock_mapping to the ioworker list. I'll add a comment.
> > + struct pvcalls_back_priv *priv;
> > + struct socket *sock;
> > + int data_worker;
> > + uint64_t id;
> > + grant_ref_t ref;
> > + struct pvcalls_data_intf *ring;
> > + void *bytes;
> > + struct pvcalls_data data;
> > + uint32_t ring_order;
> > + int irq;
> > + atomic_t read;
> > + atomic_t write;
> > + atomic_t release;
> > + void (*saved_data_ready)(struct sock *sk);
> > +};
> > +
> > +static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
> > +static int pvcalls_back_release_active(struct xenbus_device *dev,
> > + struct pvcalls_back_priv *priv,
> > + struct sock_mapping *map);
> > static void pvcalls_back_ioworker(struct work_struct *work)
> > {
> > }
> > @@ -97,9 +120,126 @@ static int pvcalls_back_socket(struct xenbus_device
> > *dev,
> > return 1;
> > }
> >
> > +static void pvcalls_sk_state_change(struct sock *sock)
> > +{
> > + struct sock_mapping *map = sock->sk_user_data;
> > + struct pvcalls_data_intf *intf;
> > +
> > + if (map == NULL)
> > + return;
> > +
> > + intf = map->ring;
> > + intf->in_error = -ENOTCONN;
> > + notify_remote_via_irq(map->irq);
> > +}
> > +
> > +static void pvcalls_sk_data_ready(struct sock *sock)
> > +{
> > +}
> > +
> > static int pvcalls_back_connect(struct xenbus_device *dev,
> > struct xen_pvcalls_request *req)
> > {
> > + struct pvcalls_back_priv *priv;
> > + int ret;
> > + struct socket *sock;
> > + struct sock_mapping *map = NULL;
> > + void *page;
> > + struct xen_pvcalls_response *rsp;
> > +
> > + if (dev == NULL)
> > + return 0;
> > + priv = dev_get_drvdata(&dev->dev);
> > +
> > + map = kzalloc(sizeof(*map), GFP_KERNEL);
> > + if (map == NULL) {
> > + ret = -ENOMEM;
> > + goto out;
> > + }
> > + ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
> > + if (ret < 0) {
> > + kfree(map);
> > + goto out;
> > + }
> > + INIT_LIST_HEAD(&map->queue);
> > + map->data_worker = get_random_int() %
> > pvcalls_back_global.nr_ioworkers;
> > +
> > + map->priv = priv;
> > + map->sock = sock;
> > + map->id = req->u.connect.id;
> > + map->ref = req->u.connect.ref;
> > +
> > + ret = xenbus_map_ring_valloc(dev, &req->u.connect.ref, 1, &page);
> > + if (ret < 0) {
> > + sock_release(map->sock);
> > + kfree(map);
> > + goto out;
> > + }
> > + map->ring = page;
> > + map->ring_order = map->ring->ring_order;
> > + /* first read the order, then map the data ring */
> > + virt_rmb();
>
>
> Not sure I understand what the barrier is for here. I don't think compiler
> will reorder ring_order access with the call.
It's to avoid using the live version of ring_order to map the data ring
pages (the other end could be changing that value at any time). We want
to be sure that the compiler doesn't optimize out map->ring_order and
use map->ring->ring_order instead.
> > + if (map->ring_order > MAX_RING_ORDER) {
> > + ret = -EFAULT;
> > + goto out;
> > + }
>
> If the barrier is indeed needed this check belongs before it.
I don't think so, see above.
>
>
> > + ret = xenbus_map_ring_valloc(dev, map->ring->ref,
> > + (1 << map->ring_order), &page);
> > + if (ret < 0) {
> > + sock_release(map->sock);
> > + xenbus_unmap_ring_vfree(dev, map->ring);
> > + kfree(map);
> > + goto out;
> > + }
> > + map->bytes = page;
> > +
> > + ret = bind_interdomain_evtchn_to_irqhandler(priv->dev->otherend_id,
> > + req->u.connect.evtchn,
> > + pvcalls_back_conn_event,
> > + 0,
> > + "pvcalls-backend",
> > + map);
> > + if (ret < 0) {
> > + sock_release(map->sock);
> > + kfree(map);
> > + goto out;
> > + }
> > + map->irq = ret;
> > +
> > + map->data.in = map->bytes;
> > + map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
> > +
> > + down_write(&priv->pvcallss_lock);
> > + list_add_tail(&map->list, &priv->socket_mappings);
> > + up_write(&priv->pvcallss_lock);
> > +
> > + ret = inet_stream_connect(sock, (struct sockaddr
> > *)&req->u.connect.addr,
> > + req->u.connect.len, req->u.connect.flags);
> > + if (ret < 0) {
> > + pvcalls_back_release_active(dev, priv, map);
> > + } else {
> > + lock_sock(sock->sk);
> > + map->saved_data_ready = sock->sk->sk_data_ready;
> > + sock->sk->sk_user_data = map;
> > + sock->sk->sk_data_ready = pvcalls_sk_data_ready;
> > + sock->sk->sk_state_change = pvcalls_sk_state_change;
> > + release_sock(sock->sk);
> > + }
> > +
> > +out:
> > + rsp = RING_GET_RESPONSE(&priv->ring, priv->ring.rsp_prod_pvt++);
> > + rsp->req_id = req->req_id;
> > + rsp->cmd = req->cmd;
> > + rsp->u.connect.id = req->u.connect.id;
> > + rsp->ret = ret;
> > +
> > + return 1;
> > +}
> > +
> > +static int pvcalls_back_release_active(struct xenbus_device *dev,
> > + struct pvcalls_back_priv *priv,
> > + struct sock_mapping *map)
> > +{
> > return 0;
> > }
> >
> > @@ -215,6 +355,11 @@ static irqreturn_t pvcalls_back_event(int irq, void
> > *dev_id)
> > return IRQ_HANDLED;
> > }
> >
> > +static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
> > +{
> > + return IRQ_HANDLED;
> > +}
> > +
> > static int backend_connect(struct xenbus_device *dev)
> > {
> > int err, evtchn;
> >
>
Powered by blists - more mailing lists