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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* -*- 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 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/mm.h>
Paul Gortmakerbc3b2d72011-07-15 11:47:34 -040015#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/sysctl.h>
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110017#include <linux/nsproxy.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Russell King496a22b2005-10-03 14:16:34 -070019#include <net/sock.h>
20
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#ifdef CONFIG_INET
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -030022#include <net/ip.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#endif
24
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#ifdef CONFIG_NET
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -030026#include <linux/if_ether.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#endif
28
Al Viro73455092008-07-14 21:22:20 -040029static struct ctl_table_set *
Eric W. Biederman13bcc6a2016-07-16 15:22:55 -050030net_ctl_header_lookup(struct ctl_table_root *root)
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110031{
Eric W. Biederman13bcc6a2016-07-16 15:22:55 -050032 return &current->nsproxy->net_ns->sysctls;
Al Viro73455092008-07-14 21:22:20 -040033}
34
35static int is_seen(struct ctl_table_set *set)
36{
37 return &current->nsproxy->net_ns->sysctls == set;
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110038}
39
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070040/* Return standard mode bits for table entry. */
Eric W. Biederman73f7ef42012-11-16 03:02:58 +000041static int net_ctl_permissions(struct ctl_table_header *head,
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070042 struct ctl_table *table)
43{
Eric W. Biedermancff10972012-11-16 03:03:01 +000044 struct net *net = container_of(head->set, struct net, sysctls);
Eric W. Biedermancff10972012-11-16 03:03:01 +000045
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070046 /* Allow network administrator to have same access as root. */
Tyler Hicksd6169b02016-09-30 15:24:31 -070047 if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070048 int mode = (table->mode >> 6) & 7;
49 return (mode << 6) | (mode << 3) | mode;
50 }
Dmitry Torokhove79c6a42016-08-10 14:36:02 -070051
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070052 return table->mode;
53}
54
Dmitry Torokhove79c6a42016-08-10 14:36:02 -070055static 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
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110072static struct ctl_table_root net_sysctl_root = {
73 .lookup = net_ctl_header_lookup,
Stephen Hemminger4ecb9002008-07-25 01:48:32 -070074 .permissions = net_ctl_permissions,
Dmitry Torokhove79c6a42016-08-10 14:36:02 -070075 .set_ownership = net_ctl_set_ownership,
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110076};
77
Alexey Dobriyan2c8c1e72010-01-17 03:35:32 +000078static int __net_init sysctl_net_init(struct net *net)
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110079{
Eric W. Biederman9eb47c22012-01-22 21:26:00 -080080 setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110081 return 0;
82}
83
Alexey Dobriyan2c8c1e72010-01-17 03:35:32 +000084static void __net_exit sysctl_net_exit(struct net *net)
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110085{
Eric W. Biederman97324cd82012-01-09 22:19:13 -080086 retire_sysctl_set(&net->sysctls);
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110087}
88
89static struct pernet_operations sysctl_pernet_ops = {
90 .init = sysctl_net_init,
91 .exit = sysctl_net_exit,
92};
93
Eric W. Biedermanbc8a3692012-04-19 13:19:46 +000094static struct ctl_table_header *net_header;
Eric W. Biederman2ca794e2012-04-19 13:20:32 +000095__init int net_sysctl_init(void)
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +110096{
Eric W. Biedermanbc8a3692012-04-19 13:19:46 +000097 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;
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100106 ret = register_pernet_subsys(&sysctl_pernet_ops);
107 if (ret)
Li RongQingce9d9b82015-10-23 20:59:49 +0800108 goto out1;
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100109out:
110 return ret;
Li RongQingce9d9b82015-10-23 20:59:49 +0800111out1:
112 unregister_sysctl_table(net_header);
113 net_header = NULL;
114 goto out;
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100115}
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100116
Eric W. Biedermanab41a2c2012-04-19 13:18:47 +0000117struct ctl_table_header *register_net_sysctl(struct net *net,
118 const char *path, struct ctl_table *table)
119{
120 return __register_sysctl_table(&net->sysctls, path, table);
121}
122EXPORT_SYMBOL_GPL(register_net_sysctl);
123
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100124void unregister_net_sysctl_table(struct ctl_table_header *header)
125{
Harvey Harrisonab598592008-05-01 02:47:38 -0700126 unregister_sysctl_table(header);
Eric W. Biederman95bdfcc2007-11-30 23:55:42 +1100127}
128EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);