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Message-Id: <1411478430-4989-2-git-send-email-nicolas.dichtel@6wind.com>
Date: Tue, 23 Sep 2014 15:20:26 +0200
From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
To: netdev@...r.kernel.org, containers@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org, linux-api@...r.kernel.org
Cc: davem@...emloft.net, ebiederm@...ssion.com,
stephen@...workplumber.org, akpm@...ux-foundation.org,
luto@...capital.net, Nicolas Dichtel <nicolas.dichtel@...nd.com>
Subject: [RFC PATCH net-next v2 1/5] netns: allocate netns ids
With this patch, an id is allocated for each netns. Id database is stored in the
user namespace. It's allowed to get an id of a peer netns only if they share the
same user ns.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
---
include/linux/user_namespace.h | 4 ++++
include/net/net_namespace.h | 11 +++++++++++
kernel/user_namespace.c | 6 ++++++
net/core/net_namespace.c | 20 +++++++++++++++++++-
4 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index e95372654f09..9d122b540422 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -5,6 +5,7 @@
#include <linux/nsproxy.h>
#include <linux/sched.h>
#include <linux/err.h>
+#include <linux/idr.h>
#define UID_GID_MAP_MAX_EXTENTS 5
@@ -33,6 +34,9 @@ struct user_namespace {
struct key *persistent_keyring_register;
struct rw_semaphore persistent_keyring_register_sem;
#endif
+#ifdef CONFIG_NET_NS
+ struct idr netns_ids;
+#endif
};
extern struct user_namespace init_user_ns;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 361d26077196..92b5f94e2842 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -59,6 +59,7 @@ struct net {
struct list_head exit_list; /* Use only net_mutex */
struct user_namespace *user_ns; /* Owning user namespace */
+ int netnsid;
unsigned int proc_inum;
@@ -289,6 +290,16 @@ static inline struct net *read_pnet(struct net * const *pnet)
#define __net_initconst __initconst
#endif
+static inline int peernet2id(struct net *net, struct net *peer)
+{
+ if (net->user_ns != peer->user_ns)
+ return -EPERM;
+
+ return peer->netnsid;
+}
+
+struct net *get_net_from_netnsid(struct net *net, int id);
+
struct pernet_operations {
struct list_head list;
int (*init)(struct net *net);
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index aa312b0dc3ec..30316a2eed49 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -104,6 +104,9 @@ int create_user_ns(struct cred *new)
#ifdef CONFIG_PERSISTENT_KEYRINGS
init_rwsem(&ns->persistent_keyring_register_sem);
#endif
+#ifdef CONFIG_NET_NS
+ idr_init(&ns->netns_ids);
+#endif
return 0;
}
@@ -133,6 +136,9 @@ void free_user_ns(struct user_namespace *ns)
do {
parent = ns->parent;
+#ifdef CONFIG_NET_NS
+ idr_destroy(&ns->netns_ids);
+#endif
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
#endif
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 7f155175bba8..f44378de7831 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -144,6 +144,19 @@ static void ops_free_list(const struct pernet_operations *ops,
}
}
+struct net *get_net_from_netnsid(struct net *net, int id)
+{
+ struct net *peer;
+
+ rcu_read_lock();
+ peer = idr_find(&net->user_ns->netns_ids, id);
+ if (peer)
+ get_net(peer);
+ rcu_read_unlock();
+
+ return peer;
+}
+
/*
* setup_net runs the initializers for the network namespace object.
*/
@@ -151,13 +164,16 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
{
/* Must be called with net_mutex held */
const struct pernet_operations *ops, *saved_ops;
- int error = 0;
+ int error = 0, id;
LIST_HEAD(net_exit_list);
atomic_set(&net->count, 1);
atomic_set(&net->passive, 1);
net->dev_base_seq = 1;
net->user_ns = user_ns;
+ id = idr_alloc_cyclic(&user_ns->netns_ids, net, 1, 0, GFP_KERNEL);
+ if (id > 0)
+ net->netnsid = id;
#ifdef NETNS_REFCNT_DEBUG
atomic_set(&net->use_count, 0);
@@ -288,6 +304,8 @@ static void cleanup_net(struct work_struct *work)
list_for_each_entry(net, &net_kill_list, cleanup_list) {
list_del_rcu(&net->list);
list_add_tail(&net->exit_list, &net_exit_list);
+ if (net->netnsid)
+ idr_remove(&net->user_ns->netns_ids, net->netnsid);
}
rtnl_unlock();
--
2.1.0
--
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