bridge: make sure objects belong to container's owner

When creating various bridge objects in /sys/class/net/... make sure
that they belong to the container's owner instead of global root (if
they belong to a container/namespace).
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -26,6 +26,7 @@
 #include <net/sock.h>
 #include <linux/if_vlan.h>
 #include <net/switchdev.h>
+#include <net/net_namespace.h>
 
 #include "br_private.h"
 
@@ -204,11 +205,19 @@ static void release_nbp(struct kobject *kobj)
 	kfree(p);
 }
 
+static void brport_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	struct net_bridge_port *p = kobj_to_brport(kobj);
+
+	net_ns_get_ownership(dev_net(p->dev), uid, gid);
+}
+
 static struct kobj_type brport_ktype = {
 #ifdef CONFIG_SYSFS
 	.sysfs_ops = &brport_sysfs_ops,
 #endif
 	.release = release_nbp,
+	.get_ownership = brport_get_ownership,
 };
 
 static void destroy_nbp(struct net_bridge_port *p)

net/bridge/br_private.h

@@ -283,6 +283,8 @@ struct net_bridge_port {
 	u16				group_fwd_mask;
 };
 
+#define kobj_to_brport(obj)	container_of(obj, struct net_bridge_port, kobj)
+
 #define br_auto_port(p) ((p)->flags & BR_AUTO_MASK)
 #define br_promisc_port(p) ((p)->flags & BR_PROMISC)
 

net/bridge/br_sysfs_if.c

@@ -249,13 +249,12 @@ static const struct brport_attribute *brport_attrs[] = {
 };
 
 #define to_brport_attr(_at) container_of(_at, struct brport_attribute, attr)
-#define to_brport(obj)	container_of(obj, struct net_bridge_port, kobj)
 
 static ssize_t brport_show(struct kobject *kobj,
 			   struct attribute *attr, char *buf)
 {
 	struct brport_attribute *brport_attr = to_brport_attr(attr);
-	struct net_bridge_port *p = to_brport(kobj);
+	struct net_bridge_port *p = kobj_to_brport(kobj);
 
 	if (!brport_attr->show)
 		return -EINVAL;
@@ -268,7 +267,7 @@ static ssize_t brport_store(struct kobject *kobj,
 			    const char *buf, size_t count)
 {
 	struct brport_attribute *brport_attr = to_brport_attr(attr);
-	struct net_bridge_port *p = to_brport(kobj);
+	struct net_bridge_port *p = kobj_to_brport(kobj);
 	ssize_t ret = -EINVAL;
 	char *endp;
 	unsigned long val;