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 *
net_ctl_header_lookup(struct ctl_table_root * root,struct nsproxy * namespaces)30 net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
31 {
32 return &namespaces->net_ns->sysctls;
33 }
34
is_seen(struct ctl_table_set * set)35 static int is_seen(struct ctl_table_set *set)
36 {
37 return ¤t->nsproxy->net_ns->sysctls == set;
38 }
39
40 /* Return standard mode bits for table entry. */
net_ctl_permissions(struct ctl_table_header * head,struct ctl_table * table)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 kuid_t root_uid = make_kuid(net->user_ns, 0);
46 kgid_t root_gid = make_kgid(net->user_ns, 0);
47
48 /* Allow network administrator to have same access as root. */
49 if (ns_capable(net->user_ns, CAP_NET_ADMIN) ||
50 uid_eq(root_uid, current_euid())) {
51 int mode = (table->mode >> 6) & 7;
52 return (mode << 6) | (mode << 3) | mode;
53 }
54 /* Allow netns root group to have the same access as the root group */
55 if (in_egroup_p(root_gid)) {
56 int mode = (table->mode >> 3) & 7;
57 return (mode << 3) | mode;
58 }
59 return table->mode;
60 }
61
62 static struct ctl_table_root net_sysctl_root = {
63 .lookup = net_ctl_header_lookup,
64 .permissions = net_ctl_permissions,
65 };
66
sysctl_net_init(struct net * net)67 static int __net_init sysctl_net_init(struct net *net)
68 {
69 setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
70 return 0;
71 }
72
sysctl_net_exit(struct net * net)73 static void __net_exit sysctl_net_exit(struct net *net)
74 {
75 retire_sysctl_set(&net->sysctls);
76 }
77
78 static struct pernet_operations sysctl_pernet_ops = {
79 .init = sysctl_net_init,
80 .exit = sysctl_net_exit,
81 };
82
83 static struct ctl_table_header *net_header;
net_sysctl_init(void)84 __init int net_sysctl_init(void)
85 {
86 static struct ctl_table empty[1];
87 int ret = -ENOMEM;
88 /* Avoid limitations in the sysctl implementation by
89 * registering "/proc/sys/net" as an empty directory not in a
90 * network namespace.
91 */
92 net_header = register_sysctl("net", empty);
93 if (!net_header)
94 goto out;
95 ret = register_pernet_subsys(&sysctl_pernet_ops);
96 if (ret)
97 goto out;
98 register_sysctl_root(&net_sysctl_root);
99 out:
100 return ret;
101 }
102
register_net_sysctl(struct net * net,const char * path,struct ctl_table * table)103 struct ctl_table_header *register_net_sysctl(struct net *net,
104 const char *path, struct ctl_table *table)
105 {
106 return __register_sysctl_table(&net->sysctls, path, table);
107 }
108 EXPORT_SYMBOL_GPL(register_net_sysctl);
109
unregister_net_sysctl_table(struct ctl_table_header * header)110 void unregister_net_sysctl_table(struct ctl_table_header *header)
111 {
112 unregister_sysctl_table(header);
113 }
114 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
115