net/core/sock_diag.c

   1 /* License: GPL */
   2
   3 #include <linux/mutex.h>
   4 #include <linux/socket.h>
   5 #include <linux/skbuff.h>
   6 #include <net/netlink.h>
   7 #include <net/net_namespace.h>
   8 #include <linux/module.h>
   9 #include <net/sock.h>
  10 #include <linux/kernel.h>
  11 #include <linux/tcp.h>
  12 #include <linux/workqueue.h>
  13
  14 #include <linux/inet_diag.h>
  15 #include <linux/sock_diag.h>
  16
  17 static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
  18 static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
  19 static DEFINE_MUTEX(sock_diag_table_mutex);
  20 static struct workqueue_struct *broadcast_wq;
  21
  22 static u64 sock_gen_cookie(struct sock *sk)
  23 {
  24         while (1) {
  25                 u64 res = atomic64_read(&sk->sk_cookie);
  26
  27                 if (res)
  28                         return res;
  29                 res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
  30                 atomic64_cmpxchg(&sk->sk_cookie, 0, res);
  31         }
  32 }
  33
  34 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
  35 {
  36         u64 res;
  37
  38         if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
  39                 return 0;
  40
  41         res = sock_gen_cookie(sk);
  42         if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
  43                 return -ESTALE;
  44
  45         return 0;
  46 }
  47 EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
  48
  49 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
  50 {
  51         u64 res = sock_gen_cookie(sk);
  52
  53         cookie[0] = (u32)res;
  54         cookie[1] = (u32)(res >> 32);
  55 }
  56 EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
  57
  58 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
  59 {
  60         u32 mem[SK_MEMINFO_VARS];
  61
  62         mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
  63         mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
  64         mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
  65         mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
  66         mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
  67         mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
  68         mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
  69         mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len;
  70         mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops);
  71
  72         return nla_put(skb, attrtype, sizeof(mem), &mem);
  73 }
  74 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
  75
  76 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
  77                              struct sk_buff *skb, int attrtype)
  78 {
  79         struct sock_fprog_kern *fprog;
  80         struct sk_filter *filter;
  81         struct nlattr *attr;
  82         unsigned int flen;
  83         int err = 0;
  84
  85         if (!may_report_filterinfo) {
  86                 nla_reserve(skb, attrtype, 0);
  87                 return 0;
  88         }
  89
  90         rcu_read_lock();
  91         filter = rcu_dereference(sk->sk_filter);
  92         if (!filter)
  93                 goto out;
  94
  95         fprog = filter->prog->orig_prog;
  96         if (!fprog)
  97                 goto out;
  98
  99         flen = bpf_classic_proglen(fprog);
 100
 101         attr = nla_reserve(skb, attrtype, flen);
 102         if (attr == NULL) {
 103                 err = -EMSGSIZE;
 104                 goto out;
 105         }
 106
 107         memcpy(nla_data(attr), fprog->filter, flen);
 108 out:
 109         rcu_read_unlock();
 110         return err;
 111 }
 112 EXPORT_SYMBOL(sock_diag_put_filterinfo);
 113
 114 struct broadcast_sk {
 115         struct sock *sk;
 116         struct work_struct work;
 117 };
 118
 119 static size_t sock_diag_nlmsg_size(void)
 120 {
 121         return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
 122                + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
 123                + nla_total_size_64bit(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
 124 }
 125
 126 static void sock_diag_broadcast_destroy_work(struct work_struct *work)
 127 {
 128         struct broadcast_sk *bsk =
 129                 container_of(work, struct broadcast_sk, work);
 130         struct sock *sk = bsk->sk;
 131         const struct sock_diag_handler *hndl;
 132         struct sk_buff *skb;
 133         const enum sknetlink_groups group = sock_diag_destroy_group(sk);
 134         int err = -1;
 135
 136         WARN_ON(group == SKNLGRP_NONE);
 137
 138         skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
 139         if (!skb)
 140                 goto out;
 141
 142         mutex_lock(&sock_diag_table_mutex);
 143         hndl = sock_diag_handlers[sk->sk_family];
 144         if (hndl && hndl->get_info)
 145                 err = hndl->get_info(skb, sk);
 146         mutex_unlock(&sock_diag_table_mutex);
 147
 148         if (!err)
 149                 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
 150                                 GFP_KERNEL);
 151         else
 152                 kfree_skb(skb);
 153 out:
 154         sk_destruct(sk);
 155         kfree(bsk);
 156 }
 157
 158 void sock_diag_broadcast_destroy(struct sock *sk)
 159 {
 160         /* Note, this function is often called from an interrupt context. */
 161         struct broadcast_sk *bsk =
 162                 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
 163         if (!bsk)
 164                 return sk_destruct(sk);
 165         bsk->sk = sk;
 166         INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
 167         queue_work(broadcast_wq, &bsk->work);
 168 }
 169
 170 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 171 {
 172         mutex_lock(&sock_diag_table_mutex);
 173         inet_rcv_compat = fn;
 174         mutex_unlock(&sock_diag_table_mutex);
 175 }
 176 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
 177
 178 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 179 {
 180         mutex_lock(&sock_diag_table_mutex);
 181         inet_rcv_compat = NULL;
 182         mutex_unlock(&sock_diag_table_mutex);
 183 }
 184 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
 185
 186 int sock_diag_register(const struct sock_diag_handler *hndl)
 187 {
 188         int err = 0;
 189
 190         if (hndl->family >= AF_MAX)
 191                 return -EINVAL;
 192
 193         mutex_lock(&sock_diag_table_mutex);
 194         if (sock_diag_handlers[hndl->family])
 195                 err = -EBUSY;
 196         else
 197                 sock_diag_handlers[hndl->family] = hndl;
 198         mutex_unlock(&sock_diag_table_mutex);
 199
 200         return err;
 201 }
 202 EXPORT_SYMBOL_GPL(sock_diag_register);
 203
 204 void sock_diag_unregister(const struct sock_diag_handler *hnld)
 205 {
 206         int family = hnld->family;
 207
 208         if (family >= AF_MAX)
 209                 return;
 210
 211         mutex_lock(&sock_diag_table_mutex);
 212         BUG_ON(sock_diag_handlers[family] != hnld);
 213         sock_diag_handlers[family] = NULL;
 214         mutex_unlock(&sock_diag_table_mutex);
 215 }
 216 EXPORT_SYMBOL_GPL(sock_diag_unregister);
 217
 218 static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
 219 {
 220         int err;
 221         struct sock_diag_req *req = nlmsg_data(nlh);
 222         const struct sock_diag_handler *hndl;
 223
 224         if (nlmsg_len(nlh) < sizeof(*req))
 225                 return -EINVAL;
 226
 227         if (req->sdiag_family >= AF_MAX)
 228                 return -EINVAL;
 229
 230         if (sock_diag_handlers[req->sdiag_family] == NULL)
 231                 request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 232                                 NETLINK_SOCK_DIAG, req->sdiag_family);
 233
 234         mutex_lock(&sock_diag_table_mutex);
 235         hndl = sock_diag_handlers[req->sdiag_family];
 236         if (hndl == NULL)
 237                 err = -ENOENT;
 238         else if (nlh->nlmsg_type == SOCK_DIAG_BY_FAMILY)
 239                 err = hndl->dump(skb, nlh);
 240         else if (nlh->nlmsg_type == SOCK_DESTROY && hndl->destroy)
 241                 err = hndl->destroy(skb, nlh);
 242         else
 243                 err = -EOPNOTSUPP;
 244         mutex_unlock(&sock_diag_table_mutex);
 245
 246         return err;
 247 }
 248
 249 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 250 {
 251         int ret;
 252
 253         switch (nlh->nlmsg_type) {
 254         case TCPDIAG_GETSOCK:
 255         case DCCPDIAG_GETSOCK:
 256                 if (inet_rcv_compat == NULL)
 257                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 258                                         NETLINK_SOCK_DIAG, AF_INET);
 259
 260                 mutex_lock(&sock_diag_table_mutex);
 261                 if (inet_rcv_compat != NULL)
 262                         ret = inet_rcv_compat(skb, nlh);
 263                 else
 264                         ret = -EOPNOTSUPP;
 265                 mutex_unlock(&sock_diag_table_mutex);
 266
 267                 return ret;
 268         case SOCK_DIAG_BY_FAMILY:
 269         case SOCK_DESTROY:
 270                 return __sock_diag_cmd(skb, nlh);
 271         default:
 272                 return -EINVAL;
 273         }
 274 }
 275
 276 static DEFINE_MUTEX(sock_diag_mutex);
 277
 278 static void sock_diag_rcv(struct sk_buff *skb)
 279 {
 280         mutex_lock(&sock_diag_mutex);
 281         netlink_rcv_skb(skb, &sock_diag_rcv_msg);
 282         mutex_unlock(&sock_diag_mutex);
 283 }
 284
 285 static int sock_diag_bind(struct net *net, int group)
 286 {
 287         switch (group) {
 288         case SKNLGRP_INET_TCP_DESTROY:
 289         case SKNLGRP_INET_UDP_DESTROY:
 290                 if (!sock_diag_handlers[AF_INET])
 291                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 292                                        NETLINK_SOCK_DIAG, AF_INET);
 293                 break;
 294         case SKNLGRP_INET6_TCP_DESTROY:
 295         case SKNLGRP_INET6_UDP_DESTROY:
 296                 if (!sock_diag_handlers[AF_INET6])
 297                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 298                                        NETLINK_SOCK_DIAG, AF_INET);
 299                 break;
 300         }
 301         return 0;
 302 }
 303
 304 int sock_diag_destroy(struct sock *sk, int err)
 305 {
 306         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
 307                 return -EPERM;
 308
 309         if (!sk->sk_prot->diag_destroy)
 310                 return -EOPNOTSUPP;
 311
 312         return sk->sk_prot->diag_destroy(sk, err);
 313 }
 314 EXPORT_SYMBOL_GPL(sock_diag_destroy);
 315
 316 static int __net_init diag_net_init(struct net *net)
 317 {
 318         struct netlink_kernel_cfg cfg = {
 319                 .groups = SKNLGRP_MAX,
 320                 .input  = sock_diag_rcv,
 321                 .bind   = sock_diag_bind,
 322                 .flags  = NL_CFG_F_NONROOT_RECV,
 323         };
 324
 325         net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
 326         return net->diag_nlsk == NULL ? -ENOMEM : 0;
 327 }
 328
 329 static void __net_exit diag_net_exit(struct net *net)
 330 {
 331         netlink_kernel_release(net->diag_nlsk);
 332         net->diag_nlsk = NULL;
 333 }
 334
 335 static struct pernet_operations diag_net_ops = {
 336         .init = diag_net_init,
 337         .exit = diag_net_exit,
 338 };
 339
 340 static int __init sock_diag_init(void)
 341 {
 342         broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
 343         BUG_ON(!broadcast_wq);
 344         return register_pernet_subsys(&diag_net_ops);
 345 }
 346 device_initcall(sock_diag_init);