Commit fbdeaed4 authored by Tyler Hicks's avatar Tyler Hicks Committed by David S. Miller
Browse files

net: create reusable function for getting ownership info of sysfs inodes 



Make net_ns_get_ownership() reusable by networking code outside of core.
This is useful, for example, to allow bridge related sysfs files to be
owned by container root.

Add a function comment since this is a potentially dangerous function to
use given the way that kobject_get_ownership() works by initializing uid
and gid before calling .get_ownership().

Signed-off-by: default avatarTyler Hicks <tyhicks@canonical.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b0e37c0d

include/net/net_namespace.h

+10 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/workqueue.h>

#include <linux/list.h>

#include <linux/sysctl.h>

#include <linux/uidgid.h>



#include <net/flow.h>

#include <net/netns/core.h>
@@ -170,6 +171,8 @@ extern struct net init_net; 
struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,

			struct net *old_net);



void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid);



void net_ns_barrier(void);

#else /* CONFIG_NET_NS */

#include <linux/sched.h>
@@ -182,6 +185,13 @@ static inline struct net *copy_net_ns(unsigned long flags, 
	return old_net;

}



static inline void net_ns_get_ownership(const struct net *net,

					kuid_t *uid, kgid_t *gid)

{

	*uid = GLOBAL_ROOT_UID;

	*gid = GLOBAL_ROOT_GID;

}



static inline void net_ns_barrier(void) {}

#endif /* CONFIG_NET_NS */

net/core/net-sysfs.c

+0 −18
Original line number Diff line number Diff line
@@ -656,24 +656,6 @@ static const struct attribute_group wireless_group = { 
#define net_class_groups	NULL

#endif /* CONFIG_SYSFS */



static void net_ns_get_ownership(const struct net *net,

				 kuid_t *uid, kgid_t *gid)

{

	if (net) {

		kuid_t ns_root_uid = make_kuid(net->user_ns, 0);

		kgid_t ns_root_gid = make_kgid(net->user_ns, 0);



		if (uid_valid(ns_root_uid))

			*uid = ns_root_uid;



		if (gid_valid(ns_root_gid))

			*gid = ns_root_gid;

	} else {

		*uid = GLOBAL_ROOT_UID;

		*gid = GLOBAL_ROOT_GID;

	}

}



#ifdef CONFIG_SYSFS

#define to_rx_queue_attr(_attr) \

	container_of(_attr, struct rx_queue_attribute, attr)

net/core/net_namespace.c

+28 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/user_namespace.h>

#include <linux/net_namespace.h>

#include <linux/sched/task.h>

#include <linux/uidgid.h>



#include <net/sock.h>

#include <net/netlink.h>
@@ -448,6 +449,33 @@ dec_ucounts: 
	return net;

}



/**

 * net_ns_get_ownership - get sysfs ownership data for @net

 * @net: network namespace in question (can be NULL)

 * @uid: kernel user ID for sysfs objects

 * @gid: kernel group ID for sysfs objects

 *

 * Returns the uid/gid pair of root in the user namespace associated with the

 * given network namespace.

 */

void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)

{

	if (net) {

		kuid_t ns_root_uid = make_kuid(net->user_ns, 0);

		kgid_t ns_root_gid = make_kgid(net->user_ns, 0);



		if (uid_valid(ns_root_uid))

			*uid = ns_root_uid;



		if (gid_valid(ns_root_gid))

			*gid = ns_root_gid;

	} else {

		*uid = GLOBAL_ROOT_UID;

		*gid = GLOBAL_ROOT_GID;

	}

}

EXPORT_SYMBOL_GPL(net_ns_get_ownership);



static void unhash_nsid(struct net *net, struct net *last)

{

	struct net *tmp;

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