path: root/net/sysctl_net.c (plain)
blob: 919981324171bd2028ed3a8662d16bf77f520c1a

1	/* -*- linux-c -*-
2	* sysctl_net.c: sysctl interface to net subsystem.
3	*
4	* Begun April 1, 1996, Mike Shaver.
5	* Added /proc/sys/net directories for each protocol family. [MS]
6	*
7	* Revision 1.2 1996/05/08 20:24:40 shaver
8	* Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
9	* NET_IPV4_IP_FORWARD.
10	*
11	*
12	*/
13
14	#include <linux/mm.h>
15	#include <linux/export.h>
16	#include <linux/sysctl.h>
17	#include <linux/nsproxy.h>
18
19	#include <net/sock.h>
20
21	#ifdef CONFIG_INET
22	#include <net/ip.h>
23	#endif
24
25	#ifdef CONFIG_NET
26	#include <linux/if_ether.h>
27	#endif
28
29	static struct ctl_table_set *
30	net_ctl_header_lookup(struct ctl_table_root *root)
31	{
32	return &current->nsproxy->net_ns->sysctls;
33	}
34
35	static int is_seen(struct ctl_table_set *set)
36	{
37	return &current->nsproxy->net_ns->sysctls == set;
38	}
39
40	/* Return standard mode bits for table entry. */
41	static int net_ctl_permissions(struct ctl_table_header *head,
42	struct ctl_table *table)
43	{
44	struct net *net = container_of(head->set, struct net, sysctls);
45
46	/* Allow network administrator to have same access as root. */
47	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
48	int mode = (table->mode >> 6) & 7;
49	return (mode << 6) | (mode << 3) | mode;
50	}
51
52	return table->mode;
53	}
54
55	static void net_ctl_set_ownership(struct ctl_table_header *head,
56	struct ctl_table *table,
57	kuid_t *uid, kgid_t *gid)
58	{
59	struct net *net = container_of(head->set, struct net, sysctls);
60	kuid_t ns_root_uid;
61	kgid_t ns_root_gid;
62
63	ns_root_uid = make_kuid(net->user_ns, 0);
64	if (uid_valid(ns_root_uid))
65	*uid = ns_root_uid;
66
67	ns_root_gid = make_kgid(net->user_ns, 0);
68	if (gid_valid(ns_root_gid))
69	*gid = ns_root_gid;
70	}
71
72	static struct ctl_table_root net_sysctl_root = {
73	.lookup = net_ctl_header_lookup,
74	.permissions = net_ctl_permissions,
75	.set_ownership = net_ctl_set_ownership,
76	};
77
78	static int __net_init sysctl_net_init(struct net *net)
79	{
80	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
81	return 0;
82	}
83
84	static void __net_exit sysctl_net_exit(struct net *net)
85	{
86	retire_sysctl_set(&net->sysctls);
87	}
88
89	static struct pernet_operations sysctl_pernet_ops = {
90	.init = sysctl_net_init,
91	.exit = sysctl_net_exit,
92	};
93
94	static struct ctl_table_header *net_header;
95	__init int net_sysctl_init(void)
96	{
97	static struct ctl_table empty[1];
98	int ret = -ENOMEM;
99	/* Avoid limitations in the sysctl implementation by
100	* registering "/proc/sys/net" as an empty directory not in a
101	* network namespace.
102	*/
103	net_header = register_sysctl("net", empty);
104	if (!net_header)
105	goto out;
106	ret = register_pernet_subsys(&sysctl_pernet_ops);
107	if (ret)
108	goto out1;
109	register_sysctl_root(&net_sysctl_root);
110	out:
111	return ret;
112	out1:
113	unregister_sysctl_table(net_header);
114	net_header = NULL;
115	goto out;
116	}
117
118	struct ctl_table_header *register_net_sysctl(struct net *net,
119	const char *path, struct ctl_table *table)
120	{
121	return __register_sysctl_table(&net->sysctls, path, table);
122	}
123	EXPORT_SYMBOL_GPL(register_net_sysctl);
124
125	void unregister_net_sysctl_table(struct ctl_table_header *header)
126	{
127	unregister_sysctl_table(header);
128	}
129	EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
130