xref: /openbmc/linux/net/sysctl_net.c (revision 25985edc)
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/sysctl.h>
16 #include <linux/nsproxy.h>
17 
18 #include <net/sock.h>
19 
20 #ifdef CONFIG_INET
21 #include <net/ip.h>
22 #endif
23 
24 #ifdef CONFIG_NET
25 #include <linux/if_ether.h>
26 #endif
27 
28 #ifdef CONFIG_TR
29 #include <linux/if_tr.h>
30 #endif
31 
32 static struct ctl_table_set *
33 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
34 {
35 	return &namespaces->net_ns->sysctls;
36 }
37 
38 static int is_seen(struct ctl_table_set *set)
39 {
40 	return &current->nsproxy->net_ns->sysctls == set;
41 }
42 
43 /* Return standard mode bits for table entry. */
44 static int net_ctl_permissions(struct ctl_table_root *root,
45 			       struct nsproxy *nsproxy,
46 			       struct ctl_table *table)
47 {
48 	/* Allow network administrator to have same access as root. */
49 	if (capable(CAP_NET_ADMIN)) {
50 		int mode = (table->mode >> 6) & 7;
51 		return (mode << 6) | (mode << 3) | mode;
52 	}
53 	return table->mode;
54 }
55 
56 static struct ctl_table_root net_sysctl_root = {
57 	.lookup = net_ctl_header_lookup,
58 	.permissions = net_ctl_permissions,
59 };
60 
61 static int net_ctl_ro_header_perms(struct ctl_table_root *root,
62 		struct nsproxy *namespaces, struct ctl_table *table)
63 {
64 	if (net_eq(namespaces->net_ns, &init_net))
65 		return table->mode;
66 	else
67 		return table->mode & ~0222;
68 }
69 
70 static struct ctl_table_root net_sysctl_ro_root = {
71 	.permissions = net_ctl_ro_header_perms,
72 };
73 
74 static int __net_init sysctl_net_init(struct net *net)
75 {
76 	setup_sysctl_set(&net->sysctls,
77 			 &net_sysctl_ro_root.default_set,
78 			 is_seen);
79 	return 0;
80 }
81 
82 static void __net_exit sysctl_net_exit(struct net *net)
83 {
84 	WARN_ON(!list_empty(&net->sysctls.list));
85 }
86 
87 static struct pernet_operations sysctl_pernet_ops = {
88 	.init = sysctl_net_init,
89 	.exit = sysctl_net_exit,
90 };
91 
92 static __init int sysctl_init(void)
93 {
94 	int ret;
95 	ret = register_pernet_subsys(&sysctl_pernet_ops);
96 	if (ret)
97 		goto out;
98 	register_sysctl_root(&net_sysctl_root);
99 	setup_sysctl_set(&net_sysctl_ro_root.default_set, NULL, NULL);
100 	register_sysctl_root(&net_sysctl_ro_root);
101 out:
102 	return ret;
103 }
104 subsys_initcall(sysctl_init);
105 
106 struct ctl_table_header *register_net_sysctl_table(struct net *net,
107 	const struct ctl_path *path, struct ctl_table *table)
108 {
109 	struct nsproxy namespaces;
110 	namespaces = *current->nsproxy;
111 	namespaces.net_ns = net;
112 	return __register_sysctl_paths(&net_sysctl_root,
113 					&namespaces, path, table);
114 }
115 EXPORT_SYMBOL_GPL(register_net_sysctl_table);
116 
117 struct ctl_table_header *register_net_sysctl_rotable(const
118 		struct ctl_path *path, struct ctl_table *table)
119 {
120 	return __register_sysctl_paths(&net_sysctl_ro_root,
121 			&init_nsproxy, path, table);
122 }
123 EXPORT_SYMBOL_GPL(register_net_sysctl_rotable);
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