LXR linux/net/sysctl

   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
  29static struct ctl_table_set *
  30net_ctl_header_lookup(struct ctl_table_root *root)
  31{
  32        return &current->nsproxy->net_ns->sysctls;
  33}
  34
  35static 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. */
  41static 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
  55static 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
  72static 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
  78static 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
  84static void __net_exit sysctl_net_exit(struct net *net)
  85{
  86        retire_sysctl_set(&net->sysctls);
  87}
  88
  89static struct pernet_operations sysctl_pernet_ops = {
  90        .init = sysctl_net_init,
  91        .exit = sysctl_net_exit,
  92};
  93
  94static 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);
 110out:
 111        return ret;
 112out1:
 113        unregister_sysctl_table(net_header);
 114        net_header = NULL;
 115        goto out;
 116}
 117
 118struct 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}
 123EXPORT_SYMBOL_GPL(register_net_sysctl);
 124
 125void unregister_net_sysctl_table(struct ctl_table_header *header)
 126{
 127        unregister_sysctl_table(header);
 128}
 129EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
 130