RDMA: Check net namespace access for uverbs, umad, cma and nldev

Introduce an API rdma_dev_access_netns() to check whether a rdma device
can be accessed from the specified net namespace or not.
Use rdma_dev_access_netns() while opening character uverbs, umad network
device and also check while rdma cm_id binds to rdma device.
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/cma.c

@@ -616,6 +616,9 @@ cma_validate_port(struct ib_device *device, u8 port,
 	int dev_type = dev_addr->dev_type;
 	struct net_device *ndev = NULL;
 
+	if (!rdma_dev_access_netns(device, id_priv->id.route.addr.dev_addr.net))
+		return ERR_PTR(-ENODEV);
+
 	if ((dev_type == ARPHRD_INFINIBAND) && !rdma_protocol_ib(device, port))
 		return ERR_PTR(-ENODEV);
 

drivers/infiniband/core/device.c

@@ -131,6 +131,26 @@ static bool ib_devices_shared_netns = true;
 module_param_named(netns_mode, ib_devices_shared_netns, bool, 0444);
 MODULE_PARM_DESC(netns_mode,
 		 "Share device among net namespaces; default=1 (shared)");
+/**
+ * rdma_dev_access_netns() - Return whether a rdma device can be accessed
+ *			     from a specified net namespace or not.
+ * @device:	Pointer to rdma device which needs to be checked
+ * @net:	Pointer to net namesapce for which access to be checked
+ *
+ * rdma_dev_access_netns() - Return whether a rdma device can be accessed
+ *			     from a specified net namespace or not. When
+ *			     rdma device is in shared mode, it ignores the
+ *			     net namespace. When rdma device is exclusive
+ *			     to a net namespace, rdma device net namespace is
+ *			     checked against the specified one.
+ */
+bool rdma_dev_access_netns(const struct ib_device *dev, const struct net *net)
+{
+	return (ib_devices_shared_netns ||
+		net_eq(read_pnet(&dev->coredev.rdma_net), net));
+}
+EXPORT_SYMBOL(rdma_dev_access_netns);
+
 /*
  * xarray has this behavior where it won't iterate over NULL values stored in
  * allocated arrays.  So we need our own iterator to see all values stored in

drivers/infiniband/core/user_mad.c

@@ -980,6 +980,11 @@ static int ib_umad_open(struct inode *inode, struct file *filp)
 		goto out;
 	}
 
+	if (!rdma_dev_access_netns(port->ib_dev, current->nsproxy->net_ns)) {
+		ret = -EPERM;
+		goto out;
+	}
+
 	file = kzalloc(sizeof(*file), GFP_KERNEL);
 	if (!file) {
 		ret = -ENOMEM;
@@ -1073,6 +1078,11 @@ static int ib_umad_sm_open(struct inode *inode, struct file *filp)
 		}
 	}
 
+	if (!rdma_dev_access_netns(port->ib_dev, current->nsproxy->net_ns)) {
+		ret = -EPERM;
+		goto err_up_sem;
+	}
+
 	ret = ib_modify_port(port->ib_dev, port->port_num, 0, &props);
 	if (ret)
 		goto err_up_sem;

drivers/infiniband/core/uverbs_main.c

@@ -1045,6 +1045,11 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
 		goto err;
 	}
 
+	if (!rdma_dev_access_netns(ib_dev, current->nsproxy->net_ns)) {
+		ret = -EPERM;
+		goto err;
+	}
+
 	/* In case IB device supports disassociate ucontext, there is no hard
 	 * dependency between uverbs device and its low level device.
 	 */

include/rdma/ib_verbs.h

@@ -4381,4 +4381,7 @@ static inline struct ib_device *rdma_device_to_ibdev(struct device *device)
  */
 #define rdma_device_to_drv_device(dev, drv_dev_struct, ibdev_member)           \
 	container_of(rdma_device_to_ibdev(dev), drv_dev_struct, ibdev_member)
+
+bool rdma_dev_access_netns(const struct ib_device *device,
+			   const struct net *net);
 #endif /* IB_VERBS_H */