sysctl_net.c 3.0 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /* -*- linux-c -*-
  3. * sysctl_net.c: sysctl interface to net subsystem.
  4. *
  5. * Begun April 1, 1996, Mike Shaver.
  6. * Added /proc/sys/net directories for each protocol family. [MS]
  7. *
  8. * Revision 1.2 1996/05/08 20:24:40 shaver
  9. * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
  10. * NET_IPV4_IP_FORWARD.
  11. *
  12. *
  13. */
  14. #include <linux/mm.h>
  15. #include <linux/export.h>
  16. #include <linux/sysctl.h>
  17. #include <linux/nsproxy.h>
  18. #include <net/sock.h>
  19. #ifdef CONFIG_INET
  20. #include <net/ip.h>
  21. #endif
  22. #ifdef CONFIG_NET
  23. #include <linux/if_ether.h>
  24. #endif
  25. static struct ctl_table_set *
  26. net_ctl_header_lookup(struct ctl_table_root *root)
  27. {
  28. return &current->nsproxy->net_ns->sysctls;
  29. }
  30. static int is_seen(struct ctl_table_set *set)
  31. {
  32. return &current->nsproxy->net_ns->sysctls == set;
  33. }
  34. /* Return standard mode bits for table entry. */
  35. static int net_ctl_permissions(struct ctl_table_header *head,
  36. struct ctl_table *table)
  37. {
  38. struct net *net = container_of(head->set, struct net, sysctls);
  39. /* Allow network administrator to have same access as root. */
  40. if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
  41. int mode = (table->mode >> 6) & 7;
  42. return (mode << 6) | (mode << 3) | mode;
  43. }
  44. return table->mode;
  45. }
  46. static void net_ctl_set_ownership(struct ctl_table_header *head,
  47. struct ctl_table *table,
  48. kuid_t *uid, kgid_t *gid)
  49. {
  50. struct net *net = container_of(head->set, struct net, sysctls);
  51. kuid_t ns_root_uid;
  52. kgid_t ns_root_gid;
  53. ns_root_uid = make_kuid(net->user_ns, 0);
  54. if (uid_valid(ns_root_uid))
  55. *uid = ns_root_uid;
  56. ns_root_gid = make_kgid(net->user_ns, 0);
  57. if (gid_valid(ns_root_gid))
  58. *gid = ns_root_gid;
  59. }
  60. static struct ctl_table_root net_sysctl_root = {
  61. .lookup = net_ctl_header_lookup,
  62. .permissions = net_ctl_permissions,
  63. .set_ownership = net_ctl_set_ownership,
  64. };
  65. static int __net_init sysctl_net_init(struct net *net)
  66. {
  67. setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  68. return 0;
  69. }
  70. static void __net_exit sysctl_net_exit(struct net *net)
  71. {
  72. retire_sysctl_set(&net->sysctls);
  73. }
  74. static struct pernet_operations sysctl_pernet_ops = {
  75. .init = sysctl_net_init,
  76. .exit = sysctl_net_exit,
  77. };
  78. static struct ctl_table_header *net_header;
  79. __init int net_sysctl_init(void)
  80. {
  81. static struct ctl_table empty[1];
  82. int ret = -ENOMEM;
  83. /* Avoid limitations in the sysctl implementation by
  84. * registering "/proc/sys/net" as an empty directory not in a
  85. * network namespace.
  86. */
  87. net_header = register_sysctl("net", empty);
  88. if (!net_header)
  89. goto out;
  90. ret = register_pernet_subsys(&sysctl_pernet_ops);
  91. if (ret)
  92. goto out1;
  93. out:
  94. return ret;
  95. out1:
  96. unregister_sysctl_table(net_header);
  97. net_header = NULL;
  98. goto out;
  99. }
  100. struct ctl_table_header *register_net_sysctl(struct net *net,
  101. const char *path, struct ctl_table *table)
  102. {
  103. return __register_sysctl_table(&net->sysctls, path, table);
  104. }
  105. EXPORT_SYMBOL_GPL(register_net_sysctl);
  106. void unregister_net_sysctl_table(struct ctl_table_header *header)
  107. {
  108. unregister_sysctl_table(header);
  109. }
  110. EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);