net/netfilter/nfnetlink.c

   1 /* Netfilter messages via netlink socket. Allows for user space
   2  * protocol helpers and general trouble making from userspace.
   3  *
   4  * (C) 2001 by Jay Schulist <jschlst@samba.org>,
   5  * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
   6  * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
   7  *
   8  * Initial netfilter messages via netlink development funded and
   9  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
  10  *
  11  * Further development of this code funded by Astaro AG (http://www.astaro.com)
  12  *
  13  * This software may be used and distributed according to the terms
  14  * of the GNU General Public License, incorporated herein by reference.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/socket.h>
  20 #include <linux/kernel.h>
  21 #include <linux/string.h>
  22 #include <linux/sockios.h>
  23 #include <linux/net.h>
  24 #include <linux/skbuff.h>
  25 #include <linux/uaccess.h>
  26 #include <net/sock.h>
  27 #include <linux/init.h>
  28 #include <linux/sched/signal.h>
  29
  30 #include <net/netlink.h>
  31 #include <net/netns/generic.h>
  32 #include <linux/netfilter/nfnetlink.h>
  33
  34 MODULE_LICENSE("GPL");
  35 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  36 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
  37 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
  38
  39 #define nfnl_dereference_protected(id) \
  40         rcu_dereference_protected(table[(id)].subsys, \
  41                                   lockdep_nfnl_is_held((id)))
  42
  43 #define NFNL_MAX_ATTR_COUNT     32
  44
  45 static unsigned int nfnetlink_pernet_id __read_mostly;
  46
  47 struct nfnl_net {
  48         struct sock *nfnl;
  49 };
  50
  51 static struct {
  52         struct mutex                            mutex;
  53         const struct nfnetlink_subsystem __rcu  *subsys;
  54 } table[NFNL_SUBSYS_COUNT];
  55
  56 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
  57
  58 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
  59         [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
  60         [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
  61         [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
  62         [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
  63         [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
  64         [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
  65         [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
  66         [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
  67         [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
  68         [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
  69         [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
  70         [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
  71         [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook",
  72 };
  73
  74 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
  75         [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
  76         [NFNLGRP_CONNTRACK_UPDATE]      = NFNL_SUBSYS_CTNETLINK,
  77         [NFNLGRP_CONNTRACK_DESTROY]     = NFNL_SUBSYS_CTNETLINK,
  78         [NFNLGRP_CONNTRACK_EXP_NEW]     = NFNL_SUBSYS_CTNETLINK_EXP,
  79         [NFNLGRP_CONNTRACK_EXP_UPDATE]  = NFNL_SUBSYS_CTNETLINK_EXP,
  80         [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
  81         [NFNLGRP_NFTABLES]              = NFNL_SUBSYS_NFTABLES,
  82         [NFNLGRP_ACCT_QUOTA]            = NFNL_SUBSYS_ACCT,
  83         [NFNLGRP_NFTRACE]               = NFNL_SUBSYS_NFTABLES,
  84 };
  85
  86 static struct nfnl_net *nfnl_pernet(struct net *net)
  87 {
  88         return net_generic(net, nfnetlink_pernet_id);
  89 }
  90
  91 void nfnl_lock(__u8 subsys_id)
  92 {
  93         mutex_lock(&table[subsys_id].mutex);
  94 }
  95 EXPORT_SYMBOL_GPL(nfnl_lock);
  96
  97 void nfnl_unlock(__u8 subsys_id)
  98 {
  99         mutex_unlock(&table[subsys_id].mutex);
 100 }
 101 EXPORT_SYMBOL_GPL(nfnl_unlock);
 102
 103 #ifdef CONFIG_PROVE_LOCKING
 104 bool lockdep_nfnl_is_held(u8 subsys_id)
 105 {
 106         return lockdep_is_held(&table[subsys_id].mutex);
 107 }
 108 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
 109 #endif
 110
 111 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
 112 {
 113         u8 cb_id;
 114
 115         /* Sanity-check attr_count size to avoid stack buffer overflow. */
 116         for (cb_id = 0; cb_id < n->cb_count; cb_id++)
 117                 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
 118                         return -EINVAL;
 119
 120         nfnl_lock(n->subsys_id);
 121         if (table[n->subsys_id].subsys) {
 122                 nfnl_unlock(n->subsys_id);
 123                 return -EBUSY;
 124         }
 125         rcu_assign_pointer(table[n->subsys_id].subsys, n);
 126         nfnl_unlock(n->subsys_id);
 127
 128         return 0;
 129 }
 130 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
 131
 132 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
 133 {
 134         nfnl_lock(n->subsys_id);
 135         table[n->subsys_id].subsys = NULL;
 136         nfnl_unlock(n->subsys_id);
 137         synchronize_rcu();
 138         return 0;
 139 }
 140 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
 141
 142 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
 143 {
 144         u8 subsys_id = NFNL_SUBSYS_ID(type);
 145
 146         if (subsys_id >= NFNL_SUBSYS_COUNT)
 147                 return NULL;
 148
 149         return rcu_dereference(table[subsys_id].subsys);
 150 }
 151
 152 static inline const struct nfnl_callback *
 153 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
 154 {
 155         u8 cb_id = NFNL_MSG_TYPE(type);
 156
 157         if (cb_id >= ss->cb_count)
 158                 return NULL;
 159
 160         return &ss->cb[cb_id];
 161 }
 162
 163 int nfnetlink_has_listeners(struct net *net, unsigned int group)
 164 {
 165         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 166
 167         return netlink_has_listeners(nfnlnet->nfnl, group);
 168 }
 169 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
 170
 171 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
 172                    unsigned int group, int echo, gfp_t flags)
 173 {
 174         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 175
 176         return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags);
 177 }
 178 EXPORT_SYMBOL_GPL(nfnetlink_send);
 179
 180 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
 181 {
 182         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 183
 184         return netlink_set_err(nfnlnet->nfnl, portid, group, error);
 185 }
 186 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
 187
 188 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
 189 {
 190         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 191         int err;
 192
 193         err = nlmsg_unicast(nfnlnet->nfnl, skb, portid);
 194         if (err == -EAGAIN)
 195                 err = -ENOBUFS;
 196
 197         return err;
 198 }
 199 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
 200
 201 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
 202                          __u32 group, gfp_t allocation)
 203 {
 204         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 205
 206         netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation);
 207 }
 208 EXPORT_SYMBOL_GPL(nfnetlink_broadcast);
 209
 210 /* Process one complete nfnetlink message. */
 211 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 212                              struct netlink_ext_ack *extack)
 213 {
 214         struct net *net = sock_net(skb->sk);
 215         const struct nfnl_callback *nc;
 216         const struct nfnetlink_subsystem *ss;
 217         int type, err;
 218
 219         /* All the messages must at least contain nfgenmsg */
 220         if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
 221                 return 0;
 222
 223         type = nlh->nlmsg_type;
 224 replay:
 225         rcu_read_lock();
 226
 227         ss = nfnetlink_get_subsys(type);
 228         if (!ss) {
 229 #ifdef CONFIG_MODULES
 230                 rcu_read_unlock();
 231                 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
 232                 rcu_read_lock();
 233                 ss = nfnetlink_get_subsys(type);
 234                 if (!ss)
 235 #endif
 236                 {
 237                         rcu_read_unlock();
 238                         return -EINVAL;
 239                 }
 240         }
 241
 242         nc = nfnetlink_find_client(type, ss);
 243         if (!nc) {
 244                 rcu_read_unlock();
 245                 return -EINVAL;
 246         }
 247
 248         {
 249                 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 250                 struct nfnl_net *nfnlnet = nfnl_pernet(net);
 251                 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 252                 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 253                 struct nlattr *attr = (void *)nlh + min_len;
 254                 int attrlen = nlh->nlmsg_len - min_len;
 255                 __u8 subsys_id = NFNL_SUBSYS_ID(type);
 256                 struct nfnl_info info = {
 257                         .net    = net,
 258                         .sk     = nfnlnet->nfnl,
 259                         .nlh    = nlh,
 260                         .nfmsg  = nlmsg_data(nlh),
 261                         .extack = extack,
 262                 };
 263
 264                 /* Sanity-check NFNL_MAX_ATTR_COUNT */
 265                 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 266                         rcu_read_unlock();
 267                         return -ENOMEM;
 268                 }
 269
 270                 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
 271                                            attr, attrlen,
 272                                            ss->cb[cb_id].policy, extack);
 273                 if (err < 0) {
 274                         rcu_read_unlock();
 275                         return err;
 276                 }
 277
 278                 if (!nc->call) {
 279                         rcu_read_unlock();
 280                         return -EINVAL;
 281                 }
 282
 283                 switch (nc->type) {
 284                 case NFNL_CB_RCU:
 285                         err = nc->call(skb, &info, (const struct nlattr **)cda);
 286                         rcu_read_unlock();
 287                         break;
 288                 case NFNL_CB_MUTEX:
 289                         rcu_read_unlock();
 290                         nfnl_lock(subsys_id);
 291                         if (nfnl_dereference_protected(subsys_id) != ss ||
 292                             nfnetlink_find_client(type, ss) != nc) {
 293                                 nfnl_unlock(subsys_id);
 294                                 err = -EAGAIN;
 295                                 break;
 296                         }
 297                         err = nc->call(skb, &info, (const struct nlattr **)cda);
 298                         nfnl_unlock(subsys_id);
 299                         break;
 300                 default:
 301                         rcu_read_unlock();
 302                         err = -EINVAL;
 303                         break;
 304                 }
 305                 if (err == -EAGAIN)
 306                         goto replay;
 307                 return err;
 308         }
 309 }
 310
 311 struct nfnl_err {
 312         struct list_head        head;
 313         struct nlmsghdr         *nlh;
 314         int                     err;
 315         struct netlink_ext_ack  extack;
 316 };
 317
 318 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
 319                         const struct netlink_ext_ack *extack)
 320 {
 321         struct nfnl_err *nfnl_err;
 322
 323         nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
 324         if (nfnl_err == NULL)
 325                 return -ENOMEM;
 326
 327         nfnl_err->nlh = nlh;
 328         nfnl_err->err = err;
 329         nfnl_err->extack = *extack;
 330         list_add_tail(&nfnl_err->head, list);
 331
 332         return 0;
 333 }
 334
 335 static void nfnl_err_del(struct nfnl_err *nfnl_err)
 336 {
 337         list_del(&nfnl_err->head);
 338         kfree(nfnl_err);
 339 }
 340
 341 static void nfnl_err_reset(struct list_head *err_list)
 342 {
 343         struct nfnl_err *nfnl_err, *next;
 344
 345         list_for_each_entry_safe(nfnl_err, next, err_list, head)
 346                 nfnl_err_del(nfnl_err);
 347 }
 348
 349 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
 350 {
 351         struct nfnl_err *nfnl_err, *next;
 352
 353         list_for_each_entry_safe(nfnl_err, next, err_list, head) {
 354                 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
 355                             &nfnl_err->extack);
 356                 nfnl_err_del(nfnl_err);
 357         }
 358 }
 359
 360 enum {
 361         NFNL_BATCH_FAILURE      = (1 << 0),
 362         NFNL_BATCH_DONE         = (1 << 1),
 363         NFNL_BATCH_REPLAY       = (1 << 2),
 364 };
 365
 366 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 367                                 u16 subsys_id, u32 genid)
 368 {
 369         struct sk_buff *oskb = skb;
 370         struct net *net = sock_net(skb->sk);
 371         const struct nfnetlink_subsystem *ss;
 372         const struct nfnl_callback *nc;
 373         struct netlink_ext_ack extack;
 374         LIST_HEAD(err_list);
 375         u32 status;
 376         int err;
 377
 378         if (subsys_id >= NFNL_SUBSYS_COUNT)
 379                 return netlink_ack(skb, nlh, -EINVAL, NULL);
 380 replay:
 381         status = 0;
 382 replay_abort:
 383         skb = netlink_skb_clone(oskb, GFP_KERNEL);
 384         if (!skb)
 385                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
 386
 387         nfnl_lock(subsys_id);
 388         ss = nfnl_dereference_protected(subsys_id);
 389         if (!ss) {
 390 #ifdef CONFIG_MODULES
 391                 nfnl_unlock(subsys_id);
 392                 request_module("nfnetlink-subsys-%d", subsys_id);
 393                 nfnl_lock(subsys_id);
 394                 ss = nfnl_dereference_protected(subsys_id);
 395                 if (!ss)
 396 #endif
 397                 {
 398                         nfnl_unlock(subsys_id);
 399                         netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 400                         return kfree_skb(skb);
 401                 }
 402         }
 403
 404         if (!ss->valid_genid || !ss->commit || !ss->abort) {
 405                 nfnl_unlock(subsys_id);
 406                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 407                 return kfree_skb(skb);
 408         }
 409
 410         if (!try_module_get(ss->owner)) {
 411                 nfnl_unlock(subsys_id);
 412                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 413                 return kfree_skb(skb);
 414         }
 415
 416         if (!ss->valid_genid(net, genid)) {
 417                 module_put(ss->owner);
 418                 nfnl_unlock(subsys_id);
 419                 netlink_ack(oskb, nlh, -ERESTART, NULL);
 420                 return kfree_skb(skb);
 421         }
 422
 423         nfnl_unlock(subsys_id);
 424
 425         while (skb->len >= nlmsg_total_size(0)) {
 426                 int msglen, type;
 427
 428                 if (fatal_signal_pending(current)) {
 429                         nfnl_err_reset(&err_list);
 430                         err = -EINTR;
 431                         status = NFNL_BATCH_FAILURE;
 432                         goto done;
 433                 }
 434
 435                 memset(&extack, 0, sizeof(extack));
 436                 nlh = nlmsg_hdr(skb);
 437                 err = 0;
 438
 439                 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
 440                     skb->len < nlh->nlmsg_len ||
 441                     nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
 442                         nfnl_err_reset(&err_list);
 443                         status |= NFNL_BATCH_FAILURE;
 444                         goto done;
 445                 }
 446
 447                 /* Only requests are handled by the kernel */
 448                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
 449                         err = -EINVAL;
 450                         goto ack;
 451                 }
 452
 453                 type = nlh->nlmsg_type;
 454                 if (type == NFNL_MSG_BATCH_BEGIN) {
 455                         /* Malformed: Batch begin twice */
 456                         nfnl_err_reset(&err_list);
 457                         status |= NFNL_BATCH_FAILURE;
 458                         goto done;
 459                 } else if (type == NFNL_MSG_BATCH_END) {
 460                         status |= NFNL_BATCH_DONE;
 461                         goto done;
 462                 } else if (type < NLMSG_MIN_TYPE) {
 463                         err = -EINVAL;
 464                         goto ack;
 465                 }
 466
 467                 /* We only accept a batch with messages for the same
 468                  * subsystem.
 469                  */
 470                 if (NFNL_SUBSYS_ID(type) != subsys_id) {
 471                         err = -EINVAL;
 472                         goto ack;
 473                 }
 474
 475                 nc = nfnetlink_find_client(type, ss);
 476                 if (!nc) {
 477                         err = -EINVAL;
 478                         goto ack;
 479                 }
 480
 481                 if (nc->type != NFNL_CB_BATCH) {
 482                         err = -EINVAL;
 483                         goto ack;
 484                 }
 485
 486                 {
 487                         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 488                         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 489                         struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 490                         struct nlattr *attr = (void *)nlh + min_len;
 491                         u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 492                         int attrlen = nlh->nlmsg_len - min_len;
 493                         struct nfnl_info info = {
 494                                 .net    = net,
 495                                 .sk     = nfnlnet->nfnl,
 496                                 .nlh    = nlh,
 497                                 .nfmsg  = nlmsg_data(nlh),
 498                                 .extack = &extack,
 499                         };
 500
 501                         /* Sanity-check NFTA_MAX_ATTR */
 502                         if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 503                                 err = -ENOMEM;
 504                                 goto ack;
 505                         }
 506
 507                         err = nla_parse_deprecated(cda,
 508                                                    ss->cb[cb_id].attr_count,
 509                                                    attr, attrlen,
 510                                                    ss->cb[cb_id].policy, NULL);
 511                         if (err < 0)
 512                                 goto ack;
 513
 514                         err = nc->call(skb, &info, (const struct nlattr **)cda);
 515
 516                         /* The lock was released to autoload some module, we
 517                          * have to abort and start from scratch using the
 518                          * original skb.
 519                          */
 520                         if (err == -EAGAIN) {
 521                                 status |= NFNL_BATCH_REPLAY;
 522                                 goto done;
 523                         }
 524                 }
 525 ack:
 526                 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
 527                         /* Errors are delivered once the full batch has been
 528                          * processed, this avoids that the same error is
 529                          * reported several times when replaying the batch.
 530                          */
 531                         if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
 532                                 /* We failed to enqueue an error, reset the
 533                                  * list of errors and send OOM to userspace
 534                                  * pointing to the batch header.
 535                                  */
 536                                 nfnl_err_reset(&err_list);
 537                                 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
 538                                             NULL);
 539                                 status |= NFNL_BATCH_FAILURE;
 540                                 goto done;
 541                         }
 542                         /* We don't stop processing the batch on errors, thus,
 543                          * userspace gets all the errors that the batch
 544                          * triggers.
 545                          */
 546                         if (err)
 547                                 status |= NFNL_BATCH_FAILURE;
 548                 }
 549
 550                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 551                 if (msglen > skb->len)
 552                         msglen = skb->len;
 553                 skb_pull(skb, msglen);
 554         }
 555 done:
 556         if (status & NFNL_BATCH_REPLAY) {
 557                 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
 558                 nfnl_err_reset(&err_list);
 559                 kfree_skb(skb);
 560                 module_put(ss->owner);
 561                 goto replay;
 562         } else if (status == NFNL_BATCH_DONE) {
 563                 err = ss->commit(net, oskb);
 564                 if (err == -EAGAIN) {
 565                         status |= NFNL_BATCH_REPLAY;
 566                         goto done;
 567                 } else if (err) {
 568                         ss->abort(net, oskb, NFNL_ABORT_NONE);
 569                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
 570                 }
 571         } else {
 572                 enum nfnl_abort_action abort_action;
 573
 574                 if (status & NFNL_BATCH_FAILURE)
 575                         abort_action = NFNL_ABORT_NONE;
 576                 else
 577                         abort_action = NFNL_ABORT_VALIDATE;
 578
 579                 err = ss->abort(net, oskb, abort_action);
 580                 if (err == -EAGAIN) {
 581                         nfnl_err_reset(&err_list);
 582                         kfree_skb(skb);
 583                         module_put(ss->owner);
 584                         status |= NFNL_BATCH_FAILURE;
 585                         goto replay_abort;
 586                 }
 587         }
 588         if (ss->cleanup)
 589                 ss->cleanup(net);
 590
 591         nfnl_err_deliver(&err_list, oskb);
 592         kfree_skb(skb);
 593         module_put(ss->owner);
 594 }
 595
 596 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
 597         [NFNL_BATCH_GENID]      = { .type = NLA_U32 },
 598 };
 599
 600 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
 601 {
 602         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 603         struct nlattr *attr = (void *)nlh + min_len;
 604         struct nlattr *cda[NFNL_BATCH_MAX + 1];
 605         int attrlen = nlh->nlmsg_len - min_len;
 606         struct nfgenmsg *nfgenmsg;
 607         int msglen, err;
 608         u32 gen_id = 0;
 609         u16 res_id;
 610
 611         msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 612         if (msglen > skb->len)
 613                 msglen = skb->len;
 614
 615         if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
 616                 return;
 617
 618         err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
 619                                    nfnl_batch_policy, NULL);
 620         if (err < 0) {
 621                 netlink_ack(skb, nlh, err, NULL);
 622                 return;
 623         }
 624         if (cda[NFNL_BATCH_GENID])
 625                 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
 626
 627         nfgenmsg = nlmsg_data(nlh);
 628         skb_pull(skb, msglen);
 629         /* Work around old nft using host byte order */
 630         if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
 631                 res_id = NFNL_SUBSYS_NFTABLES;
 632         else
 633                 res_id = ntohs(nfgenmsg->res_id);
 634
 635         nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
 636 }
 637
 638 static void nfnetlink_rcv(struct sk_buff *skb)
 639 {
 640         struct nlmsghdr *nlh = nlmsg_hdr(skb);
 641
 642         if (skb->len < NLMSG_HDRLEN ||
 643             nlh->nlmsg_len < NLMSG_HDRLEN ||
 644             skb->len < nlh->nlmsg_len)
 645                 return;
 646
 647         if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
 648                 netlink_ack(skb, nlh, -EPERM, NULL);
 649                 return;
 650         }
 651
 652         if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
 653                 nfnetlink_rcv_skb_batch(skb, nlh);
 654         else
 655                 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
 656 }
 657
 658 #ifdef CONFIG_MODULES
 659 static int nfnetlink_bind(struct net *net, int group)
 660 {
 661         const struct nfnetlink_subsystem *ss;
 662         int type;
 663
 664         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
 665                 return 0;
 666
 667         type = nfnl_group2type[group];
 668
 669         rcu_read_lock();
 670         ss = nfnetlink_get_subsys(type << 8);
 671         rcu_read_unlock();
 672         if (!ss)
 673                 request_module_nowait("nfnetlink-subsys-%d", type);
 674         return 0;
 675 }
 676 #endif
 677
 678 static int __net_init nfnetlink_net_init(struct net *net)
 679 {
 680         struct nfnl_net *nfnlnet = nfnl_pernet(net);
 681         struct netlink_kernel_cfg cfg = {
 682                 .groups = NFNLGRP_MAX,
 683                 .input  = nfnetlink_rcv,
 684 #ifdef CONFIG_MODULES
 685                 .bind   = nfnetlink_bind,
 686 #endif
 687         };
 688
 689         nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
 690         if (!nfnlnet->nfnl)
 691                 return -ENOMEM;
 692         return 0;
 693 }
 694
 695 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
 696 {
 697         struct nfnl_net *nfnlnet;
 698         struct net *net;
 699
 700         list_for_each_entry(net, net_exit_list, exit_list) {
 701                 nfnlnet = nfnl_pernet(net);
 702
 703                 netlink_kernel_release(nfnlnet->nfnl);
 704         }
 705 }
 706
 707 static struct pernet_operations nfnetlink_net_ops = {
 708         .init           = nfnetlink_net_init,
 709         .exit_batch     = nfnetlink_net_exit_batch,
 710         .id             = &nfnetlink_pernet_id,
 711         .size           = sizeof(struct nfnl_net),
 712 };
 713
 714 static int __init nfnetlink_init(void)
 715 {
 716         int i;
 717
 718         for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
 719                 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
 720
 721         for (i=0; i<NFNL_SUBSYS_COUNT; i++)
 722                 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
 723
 724         return register_pernet_subsys(&nfnetlink_net_ops);
 725 }
 726
 727 static void __exit nfnetlink_exit(void)
 728 {
 729         unregister_pernet_subsys(&nfnetlink_net_ops);
 730 }
 731 module_init(nfnetlink_init);
 732 module_exit(nfnetlink_exit);