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 err = -EAGAIN; 294 break; 295 } 296 err = nc->call(skb, &info, (const struct nlattr **)cda); 297 nfnl_unlock(subsys_id); 298 break; 299 default: 300 rcu_read_unlock(); 301 err = -EINVAL; 302 break; 303 } 304 if (err == -EAGAIN) 305 goto replay; 306 return err; 307 } 308 } 309 310 struct nfnl_err { 311 struct list_head head; 312 struct nlmsghdr *nlh; 313 int err; 314 struct netlink_ext_ack extack; 315 }; 316 317 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err, 318 const struct netlink_ext_ack *extack) 319 { 320 struct nfnl_err *nfnl_err; 321 322 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL); 323 if (nfnl_err == NULL) 324 return -ENOMEM; 325 326 nfnl_err->nlh = nlh; 327 nfnl_err->err = err; 328 nfnl_err->extack = *extack; 329 list_add_tail(&nfnl_err->head, list); 330 331 return 0; 332 } 333 334 static void nfnl_err_del(struct nfnl_err *nfnl_err) 335 { 336 list_del(&nfnl_err->head); 337 kfree(nfnl_err); 338 } 339 340 static void nfnl_err_reset(struct list_head *err_list) 341 { 342 struct nfnl_err *nfnl_err, *next; 343 344 list_for_each_entry_safe(nfnl_err, next, err_list, head) 345 nfnl_err_del(nfnl_err); 346 } 347 348 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb) 349 { 350 struct nfnl_err *nfnl_err, *next; 351 352 list_for_each_entry_safe(nfnl_err, next, err_list, head) { 353 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err, 354 &nfnl_err->extack); 355 nfnl_err_del(nfnl_err); 356 } 357 } 358 359 enum { 360 NFNL_BATCH_FAILURE = (1 << 0), 361 NFNL_BATCH_DONE = (1 << 1), 362 NFNL_BATCH_REPLAY = (1 << 2), 363 }; 364 365 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, 366 u16 subsys_id, u32 genid) 367 { 368 struct sk_buff *oskb = skb; 369 struct net *net = sock_net(skb->sk); 370 const struct nfnetlink_subsystem *ss; 371 const struct nfnl_callback *nc; 372 struct netlink_ext_ack extack; 373 LIST_HEAD(err_list); 374 u32 status; 375 int err; 376 377 if (subsys_id >= NFNL_SUBSYS_COUNT) 378 return netlink_ack(skb, nlh, -EINVAL, NULL); 379 replay: 380 status = 0; 381 replay_abort: 382 skb = netlink_skb_clone(oskb, GFP_KERNEL); 383 if (!skb) 384 return netlink_ack(oskb, nlh, -ENOMEM, NULL); 385 386 nfnl_lock(subsys_id); 387 ss = nfnl_dereference_protected(subsys_id); 388 if (!ss) { 389 #ifdef CONFIG_MODULES 390 nfnl_unlock(subsys_id); 391 request_module("nfnetlink-subsys-%d", subsys_id); 392 nfnl_lock(subsys_id); 393 ss = nfnl_dereference_protected(subsys_id); 394 if (!ss) 395 #endif 396 { 397 nfnl_unlock(subsys_id); 398 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 399 return kfree_skb(skb); 400 } 401 } 402 403 if (!ss->valid_genid || !ss->commit || !ss->abort) { 404 nfnl_unlock(subsys_id); 405 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 406 return kfree_skb(skb); 407 } 408 409 if (!try_module_get(ss->owner)) { 410 nfnl_unlock(subsys_id); 411 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 412 return kfree_skb(skb); 413 } 414 415 if (!ss->valid_genid(net, genid)) { 416 module_put(ss->owner); 417 nfnl_unlock(subsys_id); 418 netlink_ack(oskb, nlh, -ERESTART, NULL); 419 return kfree_skb(skb); 420 } 421 422 nfnl_unlock(subsys_id); 423 424 while (skb->len >= nlmsg_total_size(0)) { 425 int msglen, type; 426 427 if (fatal_signal_pending(current)) { 428 nfnl_err_reset(&err_list); 429 err = -EINTR; 430 status = NFNL_BATCH_FAILURE; 431 goto done; 432 } 433 434 memset(&extack, 0, sizeof(extack)); 435 nlh = nlmsg_hdr(skb); 436 err = 0; 437 438 if (nlh->nlmsg_len < NLMSG_HDRLEN || 439 skb->len < nlh->nlmsg_len || 440 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) { 441 nfnl_err_reset(&err_list); 442 status |= NFNL_BATCH_FAILURE; 443 goto done; 444 } 445 446 /* Only requests are handled by the kernel */ 447 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { 448 err = -EINVAL; 449 goto ack; 450 } 451 452 type = nlh->nlmsg_type; 453 if (type == NFNL_MSG_BATCH_BEGIN) { 454 /* Malformed: Batch begin twice */ 455 nfnl_err_reset(&err_list); 456 status |= NFNL_BATCH_FAILURE; 457 goto done; 458 } else if (type == NFNL_MSG_BATCH_END) { 459 status |= NFNL_BATCH_DONE; 460 goto done; 461 } else if (type < NLMSG_MIN_TYPE) { 462 err = -EINVAL; 463 goto ack; 464 } 465 466 /* We only accept a batch with messages for the same 467 * subsystem. 468 */ 469 if (NFNL_SUBSYS_ID(type) != subsys_id) { 470 err = -EINVAL; 471 goto ack; 472 } 473 474 nc = nfnetlink_find_client(type, ss); 475 if (!nc) { 476 err = -EINVAL; 477 goto ack; 478 } 479 480 if (nc->type != NFNL_CB_BATCH) { 481 err = -EINVAL; 482 goto ack; 483 } 484 485 { 486 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); 487 struct nfnl_net *nfnlnet = nfnl_pernet(net); 488 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; 489 struct nlattr *attr = (void *)nlh + min_len; 490 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); 491 int attrlen = nlh->nlmsg_len - min_len; 492 struct nfnl_info info = { 493 .net = net, 494 .sk = nfnlnet->nfnl, 495 .nlh = nlh, 496 .nfmsg = nlmsg_data(nlh), 497 .extack = &extack, 498 }; 499 500 /* Sanity-check NFTA_MAX_ATTR */ 501 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { 502 err = -ENOMEM; 503 goto ack; 504 } 505 506 err = nla_parse_deprecated(cda, 507 ss->cb[cb_id].attr_count, 508 attr, attrlen, 509 ss->cb[cb_id].policy, NULL); 510 if (err < 0) 511 goto ack; 512 513 err = nc->call(skb, &info, (const struct nlattr **)cda); 514 515 /* The lock was released to autoload some module, we 516 * have to abort and start from scratch using the 517 * original skb. 518 */ 519 if (err == -EAGAIN) { 520 status |= NFNL_BATCH_REPLAY; 521 goto done; 522 } 523 } 524 ack: 525 if (nlh->nlmsg_flags & NLM_F_ACK || err) { 526 /* Errors are delivered once the full batch has been 527 * processed, this avoids that the same error is 528 * reported several times when replaying the batch. 529 */ 530 if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) { 531 /* We failed to enqueue an error, reset the 532 * list of errors and send OOM to userspace 533 * pointing to the batch header. 534 */ 535 nfnl_err_reset(&err_list); 536 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM, 537 NULL); 538 status |= NFNL_BATCH_FAILURE; 539 goto done; 540 } 541 /* We don't stop processing the batch on errors, thus, 542 * userspace gets all the errors that the batch 543 * triggers. 544 */ 545 if (err) 546 status |= NFNL_BATCH_FAILURE; 547 } 548 549 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 550 if (msglen > skb->len) 551 msglen = skb->len; 552 skb_pull(skb, msglen); 553 } 554 done: 555 if (status & NFNL_BATCH_REPLAY) { 556 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD); 557 nfnl_err_reset(&err_list); 558 kfree_skb(skb); 559 module_put(ss->owner); 560 goto replay; 561 } else if (status == NFNL_BATCH_DONE) { 562 err = ss->commit(net, oskb); 563 if (err == -EAGAIN) { 564 status |= NFNL_BATCH_REPLAY; 565 goto done; 566 } else if (err) { 567 ss->abort(net, oskb, NFNL_ABORT_NONE); 568 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL); 569 } 570 } else { 571 enum nfnl_abort_action abort_action; 572 573 if (status & NFNL_BATCH_FAILURE) 574 abort_action = NFNL_ABORT_NONE; 575 else 576 abort_action = NFNL_ABORT_VALIDATE; 577 578 err = ss->abort(net, oskb, abort_action); 579 if (err == -EAGAIN) { 580 nfnl_err_reset(&err_list); 581 kfree_skb(skb); 582 module_put(ss->owner); 583 status |= NFNL_BATCH_FAILURE; 584 goto replay_abort; 585 } 586 } 587 if (ss->cleanup) 588 ss->cleanup(net); 589 590 nfnl_err_deliver(&err_list, oskb); 591 kfree_skb(skb); 592 module_put(ss->owner); 593 } 594 595 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = { 596 [NFNL_BATCH_GENID] = { .type = NLA_U32 }, 597 }; 598 599 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) 600 { 601 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); 602 struct nlattr *attr = (void *)nlh + min_len; 603 struct nlattr *cda[NFNL_BATCH_MAX + 1]; 604 int attrlen = nlh->nlmsg_len - min_len; 605 struct nfgenmsg *nfgenmsg; 606 int msglen, err; 607 u32 gen_id = 0; 608 u16 res_id; 609 610 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 611 if (msglen > skb->len) 612 msglen = skb->len; 613 614 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) 615 return; 616 617 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen, 618 nfnl_batch_policy, NULL); 619 if (err < 0) { 620 netlink_ack(skb, nlh, err, NULL); 621 return; 622 } 623 if (cda[NFNL_BATCH_GENID]) 624 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID])); 625 626 nfgenmsg = nlmsg_data(nlh); 627 skb_pull(skb, msglen); 628 /* Work around old nft using host byte order */ 629 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES) 630 res_id = NFNL_SUBSYS_NFTABLES; 631 else 632 res_id = ntohs(nfgenmsg->res_id); 633 634 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id); 635 } 636 637 static void nfnetlink_rcv(struct sk_buff *skb) 638 { 639 struct nlmsghdr *nlh = nlmsg_hdr(skb); 640 641 if (skb->len < NLMSG_HDRLEN || 642 nlh->nlmsg_len < NLMSG_HDRLEN || 643 skb->len < nlh->nlmsg_len) 644 return; 645 646 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { 647 netlink_ack(skb, nlh, -EPERM, NULL); 648 return; 649 } 650 651 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) 652 nfnetlink_rcv_skb_batch(skb, nlh); 653 else 654 netlink_rcv_skb(skb, nfnetlink_rcv_msg); 655 } 656 657 static int nfnetlink_bind(struct net *net, int group) 658 { 659 const struct nfnetlink_subsystem *ss; 660 int type; 661 662 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) 663 return 0; 664 665 type = nfnl_group2type[group]; 666 667 rcu_read_lock(); 668 ss = nfnetlink_get_subsys(type << 8); 669 rcu_read_unlock(); 670 if (!ss) 671 request_module_nowait("nfnetlink-subsys-%d", type); 672 673 #ifdef CONFIG_NF_CONNTRACK_EVENTS 674 if (type == NFNL_SUBSYS_CTNETLINK) { 675 nfnl_lock(NFNL_SUBSYS_CTNETLINK); 676 WRITE_ONCE(net->ct.ctnetlink_has_listener, true); 677 nfnl_unlock(NFNL_SUBSYS_CTNETLINK); 678 } 679 #endif 680 return 0; 681 } 682 683 static void nfnetlink_unbind(struct net *net, int group) 684 { 685 #ifdef CONFIG_NF_CONNTRACK_EVENTS 686 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) 687 return; 688 689 if (nfnl_group2type[group] == NFNL_SUBSYS_CTNETLINK) { 690 nfnl_lock(NFNL_SUBSYS_CTNETLINK); 691 if (!nfnetlink_has_listeners(net, group)) 692 WRITE_ONCE(net->ct.ctnetlink_has_listener, false); 693 nfnl_unlock(NFNL_SUBSYS_CTNETLINK); 694 } 695 #endif 696 } 697 698 static int __net_init nfnetlink_net_init(struct net *net) 699 { 700 struct nfnl_net *nfnlnet = nfnl_pernet(net); 701 struct netlink_kernel_cfg cfg = { 702 .groups = NFNLGRP_MAX, 703 .input = nfnetlink_rcv, 704 .bind = nfnetlink_bind, 705 .unbind = nfnetlink_unbind, 706 }; 707 708 nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); 709 if (!nfnlnet->nfnl) 710 return -ENOMEM; 711 return 0; 712 } 713 714 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) 715 { 716 struct nfnl_net *nfnlnet; 717 struct net *net; 718 719 list_for_each_entry(net, net_exit_list, exit_list) { 720 nfnlnet = nfnl_pernet(net); 721 722 netlink_kernel_release(nfnlnet->nfnl); 723 } 724 } 725 726 static struct pernet_operations nfnetlink_net_ops = { 727 .init = nfnetlink_net_init, 728 .exit_batch = nfnetlink_net_exit_batch, 729 .id = &nfnetlink_pernet_id, 730 .size = sizeof(struct nfnl_net), 731 }; 732 733 static int __init nfnetlink_init(void) 734 { 735 int i; 736 737 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++) 738 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE); 739 740 for (i=0; i<NFNL_SUBSYS_COUNT; i++) 741 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]); 742 743 return register_pernet_subsys(&nfnetlink_net_ops); 744 } 745 746 static void __exit nfnetlink_exit(void) 747 { 748 unregister_pernet_subsys(&nfnetlink_net_ops); 749 } 750 module_init(nfnetlink_init); 751 module_exit(nfnetlink_exit); 752