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 * 30 net_ctl_header_lookup(struct ctl_table_root *root) 31 { 32 return ¤t->nsproxy->net_ns->sysctls; 33 } 34 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. */ 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 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 55 static 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 72 static 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 78 static 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 84 static void __net_exit sysctl_net_exit(struct net *net) 85 { 86 retire_sysctl_set(&net->sysctls); 87 } 88 89 static struct pernet_operations sysctl_pernet_ops = { 90 .init = sysctl_net_init, 91 .exit = sysctl_net_exit, 92 }; 93 94 static 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 out: 110 return ret; 111 out1: 112 unregister_sysctl_table(net_header); 113 net_header = NULL; 114 goto out; 115 } 116 117 struct 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 } 122 EXPORT_SYMBOL_GPL(register_net_sysctl); 123 124 void unregister_net_sysctl_table(struct ctl_table_header *header) 125 { 126 unregister_sysctl_table(header); 127 } 128 EXPORT_SYMBOL_GPL(unregister_net_sysctl_table); 129