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