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, struct nsproxy *namespaces) 31 { 32 return &namespaces->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 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 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 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; 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 } 102 103 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); 109 110 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