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.h> 33 #include <linux/netfilter/nfnetlink.h> 34 35 MODULE_LICENSE("GPL"); 36 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 37 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); 38 MODULE_DESCRIPTION("Netfilter messages via netlink socket"); 39 40 #define nfnl_dereference_protected(id) \ 41 rcu_dereference_protected(table[(id)].subsys, \ 42 lockdep_nfnl_is_held((id))) 43 44 #define NFNL_MAX_ATTR_COUNT 32 45 46 static unsigned int nfnetlink_pernet_id __read_mostly; 47 48 #ifdef CONFIG_NF_CONNTRACK_EVENTS 49 static DEFINE_SPINLOCK(nfnl_grp_active_lock); 50 #endif 51 52 struct nfnl_net { 53 struct sock *nfnl; 54 }; 55 56 static struct { 57 struct mutex mutex; 58 const struct nfnetlink_subsystem __rcu *subsys; 59 } table[NFNL_SUBSYS_COUNT]; 60 61 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT]; 62 63 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = { 64 [NFNL_SUBSYS_NONE] = "nfnl_subsys_none", 65 [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink", 66 [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp", 67 [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue", 68 [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog", 69 [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf", 70 [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset", 71 [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct", 72 [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout", 73 [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper", 74 [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables", 75 [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat", 76 [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook", 77 }; 78 79 static const int nfnl_group2type[NFNLGRP_MAX+1] = { 80 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, 81 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, 82 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, 83 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, 84 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, 85 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, 86 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES, 87 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT, 88 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES, 89 }; 90 91 static struct nfnl_net *nfnl_pernet(struct net *net) 92 { 93 return net_generic(net, nfnetlink_pernet_id); 94 } 95 96 void nfnl_lock(__u8 subsys_id) 97 { 98 mutex_lock(&table[subsys_id].mutex); 99 } 100 EXPORT_SYMBOL_GPL(nfnl_lock); 101 102 void nfnl_unlock(__u8 subsys_id) 103 { 104 mutex_unlock(&table[subsys_id].mutex); 105 } 106 EXPORT_SYMBOL_GPL(nfnl_unlock); 107 108 #ifdef CONFIG_PROVE_LOCKING 109 bool lockdep_nfnl_is_held(u8 subsys_id) 110 { 111 return lockdep_is_held(&table[subsys_id].mutex); 112 } 113 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); 114 #endif 115 116 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) 117 { 118 u8 cb_id; 119 120 /* Sanity-check attr_count size to avoid stack buffer overflow. */ 121 for (cb_id = 0; cb_id < n->cb_count; cb_id++) 122 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT)) 123 return -EINVAL; 124 125 nfnl_lock(n->subsys_id); 126 if (table[n->subsys_id].subsys) { 127 nfnl_unlock(n->subsys_id); 128 return -EBUSY; 129 } 130 rcu_assign_pointer(table[n->subsys_id].subsys, n); 131 nfnl_unlock(n->subsys_id); 132 133 return 0; 134 } 135 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); 136 137 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) 138 { 139 nfnl_lock(n->subsys_id); 140 table[n->subsys_id].subsys = NULL; 141 nfnl_unlock(n->subsys_id); 142 synchronize_rcu(); 143 return 0; 144 } 145 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); 146 147 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type) 148 { 149 u8 subsys_id = NFNL_SUBSYS_ID(type); 150 151 if (subsys_id >= NFNL_SUBSYS_COUNT) 152 return NULL; 153 154 return rcu_dereference(table[subsys_id].subsys); 155 } 156 157 static inline const struct nfnl_callback * 158 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss) 159 { 160 u8 cb_id = NFNL_MSG_TYPE(type); 161 162 if (cb_id >= ss->cb_count) 163 return NULL; 164 165 return &ss->cb[cb_id]; 166 } 167 168 int nfnetlink_has_listeners(struct net *net, unsigned int group) 169 { 170 struct nfnl_net *nfnlnet = nfnl_pernet(net); 171 172 return netlink_has_listeners(nfnlnet->nfnl, group); 173 } 174 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); 175 176 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, 177 unsigned int group, int echo, gfp_t flags) 178 { 179 struct nfnl_net *nfnlnet = nfnl_pernet(net); 180 181 return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags); 182 } 183 EXPORT_SYMBOL_GPL(nfnetlink_send); 184 185 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) 186 { 187 struct nfnl_net *nfnlnet = nfnl_pernet(net); 188 189 return netlink_set_err(nfnlnet->nfnl, portid, group, error); 190 } 191 EXPORT_SYMBOL_GPL(nfnetlink_set_err); 192 193 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid) 194 { 195 struct nfnl_net *nfnlnet = nfnl_pernet(net); 196 int err; 197 198 err = nlmsg_unicast(nfnlnet->nfnl, skb, portid); 199 if (err == -EAGAIN) 200 err = -ENOBUFS; 201 202 return err; 203 } 204 EXPORT_SYMBOL_GPL(nfnetlink_unicast); 205 206 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid, 207 __u32 group, gfp_t allocation) 208 { 209 struct nfnl_net *nfnlnet = nfnl_pernet(net); 210 211 netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation); 212 } 213 EXPORT_SYMBOL_GPL(nfnetlink_broadcast); 214 215 /* Process one complete nfnetlink message. */ 216 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 217 struct netlink_ext_ack *extack) 218 { 219 struct net *net = sock_net(skb->sk); 220 const struct nfnl_callback *nc; 221 const struct nfnetlink_subsystem *ss; 222 int type, err; 223 224 /* All the messages must at least contain nfgenmsg */ 225 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) 226 return 0; 227 228 type = nlh->nlmsg_type; 229 replay: 230 rcu_read_lock(); 231 232 ss = nfnetlink_get_subsys(type); 233 if (!ss) { 234 #ifdef CONFIG_MODULES 235 rcu_read_unlock(); 236 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); 237 rcu_read_lock(); 238 ss = nfnetlink_get_subsys(type); 239 if (!ss) 240 #endif 241 { 242 rcu_read_unlock(); 243 return -EINVAL; 244 } 245 } 246 247 nc = nfnetlink_find_client(type, ss); 248 if (!nc) { 249 rcu_read_unlock(); 250 return -EINVAL; 251 } 252 253 { 254 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); 255 struct nfnl_net *nfnlnet = nfnl_pernet(net); 256 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); 257 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; 258 struct nlattr *attr = (void *)nlh + min_len; 259 int attrlen = nlh->nlmsg_len - min_len; 260 __u8 subsys_id = NFNL_SUBSYS_ID(type); 261 struct nfnl_info info = { 262 .net = net, 263 .sk = nfnlnet->nfnl, 264 .nlh = nlh, 265 .nfmsg = nlmsg_data(nlh), 266 .extack = extack, 267 }; 268 269 /* Sanity-check NFNL_MAX_ATTR_COUNT */ 270 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { 271 rcu_read_unlock(); 272 return -ENOMEM; 273 } 274 275 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count, 276 attr, attrlen, 277 ss->cb[cb_id].policy, extack); 278 if (err < 0) { 279 rcu_read_unlock(); 280 return err; 281 } 282 283 if (!nc->call) { 284 rcu_read_unlock(); 285 return -EINVAL; 286 } 287 288 switch (nc->type) { 289 case NFNL_CB_RCU: 290 err = nc->call(skb, &info, (const struct nlattr **)cda); 291 rcu_read_unlock(); 292 break; 293 case NFNL_CB_MUTEX: 294 rcu_read_unlock(); 295 nfnl_lock(subsys_id); 296 if (nfnl_dereference_protected(subsys_id) != ss || 297 nfnetlink_find_client(type, ss) != nc) { 298 nfnl_unlock(subsys_id); 299 err = -EAGAIN; 300 break; 301 } 302 err = nc->call(skb, &info, (const struct nlattr **)cda); 303 nfnl_unlock(subsys_id); 304 break; 305 default: 306 rcu_read_unlock(); 307 err = -EINVAL; 308 break; 309 } 310 if (err == -EAGAIN) 311 goto replay; 312 return err; 313 } 314 } 315 316 struct nfnl_err { 317 struct list_head head; 318 struct nlmsghdr *nlh; 319 int err; 320 struct netlink_ext_ack extack; 321 }; 322 323 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err, 324 const struct netlink_ext_ack *extack) 325 { 326 struct nfnl_err *nfnl_err; 327 328 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL); 329 if (nfnl_err == NULL) 330 return -ENOMEM; 331 332 nfnl_err->nlh = nlh; 333 nfnl_err->err = err; 334 nfnl_err->extack = *extack; 335 list_add_tail(&nfnl_err->head, list); 336 337 return 0; 338 } 339 340 static void nfnl_err_del(struct nfnl_err *nfnl_err) 341 { 342 list_del(&nfnl_err->head); 343 kfree(nfnl_err); 344 } 345 346 static void nfnl_err_reset(struct list_head *err_list) 347 { 348 struct nfnl_err *nfnl_err, *next; 349 350 list_for_each_entry_safe(nfnl_err, next, err_list, head) 351 nfnl_err_del(nfnl_err); 352 } 353 354 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb) 355 { 356 struct nfnl_err *nfnl_err, *next; 357 358 list_for_each_entry_safe(nfnl_err, next, err_list, head) { 359 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err, 360 &nfnl_err->extack); 361 nfnl_err_del(nfnl_err); 362 } 363 } 364 365 enum { 366 NFNL_BATCH_FAILURE = (1 << 0), 367 NFNL_BATCH_DONE = (1 << 1), 368 NFNL_BATCH_REPLAY = (1 << 2), 369 }; 370 371 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, 372 u16 subsys_id, u32 genid) 373 { 374 struct sk_buff *oskb = skb; 375 struct net *net = sock_net(skb->sk); 376 const struct nfnetlink_subsystem *ss; 377 const struct nfnl_callback *nc; 378 struct netlink_ext_ack extack; 379 struct nlmsghdr *onlh = nlh; 380 LIST_HEAD(err_list); 381 u32 status; 382 int err; 383 384 if (subsys_id >= NFNL_SUBSYS_COUNT) 385 return netlink_ack(skb, nlh, -EINVAL, NULL); 386 replay: 387 status = 0; 388 replay_abort: 389 skb = netlink_skb_clone(oskb, GFP_KERNEL); 390 nlh = onlh; 391 if (!skb) 392 return netlink_ack(oskb, nlh, -ENOMEM, NULL); 393 394 nfnl_lock(subsys_id); 395 ss = nfnl_dereference_protected(subsys_id); 396 if (!ss) { 397 #ifdef CONFIG_MODULES 398 nfnl_unlock(subsys_id); 399 request_module("nfnetlink-subsys-%d", subsys_id); 400 nfnl_lock(subsys_id); 401 ss = nfnl_dereference_protected(subsys_id); 402 if (!ss) 403 #endif 404 { 405 nfnl_unlock(subsys_id); 406 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 407 return consume_skb(skb); 408 } 409 } 410 411 if (!ss->valid_genid || !ss->commit || !ss->abort) { 412 nfnl_unlock(subsys_id); 413 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 414 return consume_skb(skb); 415 } 416 417 if (!try_module_get(ss->owner)) { 418 nfnl_unlock(subsys_id); 419 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL); 420 return consume_skb(skb); 421 } 422 423 if (!ss->valid_genid(net, genid)) { 424 module_put(ss->owner); 425 nfnl_unlock(subsys_id); 426 netlink_ack(oskb, nlh, -ERESTART, NULL); 427 return consume_skb(skb); 428 } 429 430 nfnl_unlock(subsys_id); 431 432 if (nlh->nlmsg_flags & NLM_F_ACK) { 433 memset(&extack, 0, sizeof(extack)); 434 nfnl_err_add(&err_list, nlh, 0, &extack); 435 } 436 437 while (skb->len >= nlmsg_total_size(0)) { 438 int msglen, type; 439 440 if (fatal_signal_pending(current)) { 441 nfnl_err_reset(&err_list); 442 err = -EINTR; 443 status = NFNL_BATCH_FAILURE; 444 goto done; 445 } 446 447 memset(&extack, 0, sizeof(extack)); 448 nlh = nlmsg_hdr(skb); 449 err = 0; 450 451 if (nlh->nlmsg_len < NLMSG_HDRLEN || 452 skb->len < nlh->nlmsg_len || 453 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) { 454 nfnl_err_reset(&err_list); 455 status |= NFNL_BATCH_FAILURE; 456 goto done; 457 } 458 459 /* Only requests are handled by the kernel */ 460 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { 461 err = -EINVAL; 462 goto ack; 463 } 464 465 type = nlh->nlmsg_type; 466 if (type == NFNL_MSG_BATCH_BEGIN) { 467 /* Malformed: Batch begin twice */ 468 nfnl_err_reset(&err_list); 469 status |= NFNL_BATCH_FAILURE; 470 goto done; 471 } else if (type == NFNL_MSG_BATCH_END) { 472 status |= NFNL_BATCH_DONE; 473 goto done; 474 } else if (type < NLMSG_MIN_TYPE) { 475 err = -EINVAL; 476 goto ack; 477 } 478 479 /* We only accept a batch with messages for the same 480 * subsystem. 481 */ 482 if (NFNL_SUBSYS_ID(type) != subsys_id) { 483 err = -EINVAL; 484 goto ack; 485 } 486 487 nc = nfnetlink_find_client(type, ss); 488 if (!nc) { 489 err = -EINVAL; 490 goto ack; 491 } 492 493 if (nc->type != NFNL_CB_BATCH) { 494 err = -EINVAL; 495 goto ack; 496 } 497 498 { 499 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); 500 struct nfnl_net *nfnlnet = nfnl_pernet(net); 501 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; 502 struct nlattr *attr = (void *)nlh + min_len; 503 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); 504 int attrlen = nlh->nlmsg_len - min_len; 505 struct nfnl_info info = { 506 .net = net, 507 .sk = nfnlnet->nfnl, 508 .nlh = nlh, 509 .nfmsg = nlmsg_data(nlh), 510 .extack = &extack, 511 }; 512 513 /* Sanity-check NFTA_MAX_ATTR */ 514 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { 515 err = -ENOMEM; 516 goto ack; 517 } 518 519 err = nla_parse_deprecated(cda, 520 ss->cb[cb_id].attr_count, 521 attr, attrlen, 522 ss->cb[cb_id].policy, &extack); 523 if (err < 0) 524 goto ack; 525 526 err = nc->call(skb, &info, (const struct nlattr **)cda); 527 528 /* The lock was released to autoload some module, we 529 * have to abort and start from scratch using the 530 * original skb. 531 */ 532 if (err == -EAGAIN) { 533 status |= NFNL_BATCH_REPLAY; 534 goto done; 535 } 536 } 537 ack: 538 if (nlh->nlmsg_flags & NLM_F_ACK || err) { 539 /* Errors are delivered once the full batch has been 540 * processed, this avoids that the same error is 541 * reported several times when replaying the batch. 542 */ 543 if (err == -ENOMEM || 544 nfnl_err_add(&err_list, nlh, err, &extack) < 0) { 545 /* We failed to enqueue an error, reset the 546 * list of errors and send OOM to userspace 547 * pointing to the batch header. 548 */ 549 nfnl_err_reset(&err_list); 550 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM, 551 NULL); 552 status |= NFNL_BATCH_FAILURE; 553 goto done; 554 } 555 /* We don't stop processing the batch on errors, thus, 556 * userspace gets all the errors that the batch 557 * triggers. 558 */ 559 if (err) 560 status |= NFNL_BATCH_FAILURE; 561 } 562 563 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 564 if (msglen > skb->len) 565 msglen = skb->len; 566 skb_pull(skb, msglen); 567 } 568 done: 569 if (status & NFNL_BATCH_REPLAY) { 570 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD); 571 nfnl_err_reset(&err_list); 572 consume_skb(skb); 573 module_put(ss->owner); 574 goto replay; 575 } else if (status == NFNL_BATCH_DONE) { 576 err = ss->commit(net, oskb); 577 if (err == -EAGAIN) { 578 status |= NFNL_BATCH_REPLAY; 579 goto done; 580 } else if (err) { 581 ss->abort(net, oskb, NFNL_ABORT_NONE); 582 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL); 583 } else if (nlh->nlmsg_flags & NLM_F_ACK) { 584 memset(&extack, 0, sizeof(extack)); 585 nfnl_err_add(&err_list, nlh, 0, &extack); 586 } 587 } else { 588 enum nfnl_abort_action abort_action; 589 590 if (status & NFNL_BATCH_FAILURE) 591 abort_action = NFNL_ABORT_NONE; 592 else 593 abort_action = NFNL_ABORT_VALIDATE; 594 595 err = ss->abort(net, oskb, abort_action); 596 if (err == -EAGAIN) { 597 nfnl_err_reset(&err_list); 598 consume_skb(skb); 599 module_put(ss->owner); 600 status |= NFNL_BATCH_FAILURE; 601 goto replay_abort; 602 } 603 } 604 605 nfnl_err_deliver(&err_list, oskb); 606 consume_skb(skb); 607 module_put(ss->owner); 608 } 609 610 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = { 611 [NFNL_BATCH_GENID] = { .type = NLA_U32 }, 612 }; 613 614 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) 615 { 616 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); 617 struct nlattr *attr = (void *)nlh + min_len; 618 struct nlattr *cda[NFNL_BATCH_MAX + 1]; 619 int attrlen = nlh->nlmsg_len - min_len; 620 struct nfgenmsg *nfgenmsg; 621 int msglen, err; 622 u32 gen_id = 0; 623 u16 res_id; 624 625 msglen = NLMSG_ALIGN(nlh->nlmsg_len); 626 if (msglen > skb->len) 627 msglen = skb->len; 628 629 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) 630 return; 631 632 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen, 633 nfnl_batch_policy, NULL); 634 if (err < 0) { 635 netlink_ack(skb, nlh, err, NULL); 636 return; 637 } 638 if (cda[NFNL_BATCH_GENID]) 639 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID])); 640 641 nfgenmsg = nlmsg_data(nlh); 642 skb_pull(skb, msglen); 643 /* Work around old nft using host byte order */ 644 if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES) 645 res_id = NFNL_SUBSYS_NFTABLES; 646 else 647 res_id = ntohs(nfgenmsg->res_id); 648 649 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id); 650 } 651 652 static void nfnetlink_rcv(struct sk_buff *skb) 653 { 654 struct nlmsghdr *nlh = nlmsg_hdr(skb); 655 656 if (skb->len < NLMSG_HDRLEN || 657 nlh->nlmsg_len < NLMSG_HDRLEN || 658 skb->len < nlh->nlmsg_len) 659 return; 660 661 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { 662 netlink_ack(skb, nlh, -EPERM, NULL); 663 return; 664 } 665 666 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) 667 nfnetlink_rcv_skb_batch(skb, nlh); 668 else 669 netlink_rcv_skb(skb, nfnetlink_rcv_msg); 670 } 671 672 static void nfnetlink_bind_event(struct net *net, unsigned int group) 673 { 674 #ifdef CONFIG_NF_CONNTRACK_EVENTS 675 int type, group_bit; 676 u8 v; 677 678 /* All NFNLGRP_CONNTRACK_* group bits fit into u8. 679 * The other groups are not relevant and can be ignored. 680 */ 681 if (group >= 8) 682 return; 683 684 type = nfnl_group2type[group]; 685 686 switch (type) { 687 case NFNL_SUBSYS_CTNETLINK: 688 break; 689 case NFNL_SUBSYS_CTNETLINK_EXP: 690 break; 691 default: 692 return; 693 } 694 695 group_bit = (1 << group); 696 697 spin_lock(&nfnl_grp_active_lock); 698 v = READ_ONCE(nf_ctnetlink_has_listener); 699 if ((v & group_bit) == 0) { 700 v |= group_bit; 701 702 /* read concurrently without nfnl_grp_active_lock held. */ 703 WRITE_ONCE(nf_ctnetlink_has_listener, v); 704 } 705 706 spin_unlock(&nfnl_grp_active_lock); 707 #endif 708 } 709 710 static int nfnetlink_bind(struct net *net, int group) 711 { 712 const struct nfnetlink_subsystem *ss; 713 int type; 714 715 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) 716 return 0; 717 718 type = nfnl_group2type[group]; 719 720 rcu_read_lock(); 721 ss = nfnetlink_get_subsys(type << 8); 722 rcu_read_unlock(); 723 if (!ss) 724 request_module_nowait("nfnetlink-subsys-%d", type); 725 726 nfnetlink_bind_event(net, group); 727 return 0; 728 } 729 730 static void nfnetlink_unbind(struct net *net, int group) 731 { 732 #ifdef CONFIG_NF_CONNTRACK_EVENTS 733 int type, group_bit; 734 735 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) 736 return; 737 738 type = nfnl_group2type[group]; 739 740 switch (type) { 741 case NFNL_SUBSYS_CTNETLINK: 742 break; 743 case NFNL_SUBSYS_CTNETLINK_EXP: 744 break; 745 default: 746 return; 747 } 748 749 /* ctnetlink_has_listener is u8 */ 750 if (group >= 8) 751 return; 752 753 group_bit = (1 << group); 754 755 spin_lock(&nfnl_grp_active_lock); 756 if (!nfnetlink_has_listeners(net, group)) { 757 u8 v = READ_ONCE(nf_ctnetlink_has_listener); 758 759 v &= ~group_bit; 760 761 /* read concurrently without nfnl_grp_active_lock held. */ 762 WRITE_ONCE(nf_ctnetlink_has_listener, v); 763 } 764 spin_unlock(&nfnl_grp_active_lock); 765 #endif 766 } 767 768 static int __net_init nfnetlink_net_init(struct net *net) 769 { 770 struct nfnl_net *nfnlnet = nfnl_pernet(net); 771 struct netlink_kernel_cfg cfg = { 772 .groups = NFNLGRP_MAX, 773 .input = nfnetlink_rcv, 774 .bind = nfnetlink_bind, 775 .unbind = nfnetlink_unbind, 776 }; 777 778 nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); 779 if (!nfnlnet->nfnl) 780 return -ENOMEM; 781 return 0; 782 } 783 784 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) 785 { 786 struct nfnl_net *nfnlnet; 787 struct net *net; 788 789 list_for_each_entry(net, net_exit_list, exit_list) { 790 nfnlnet = nfnl_pernet(net); 791 792 netlink_kernel_release(nfnlnet->nfnl); 793 } 794 } 795 796 static struct pernet_operations nfnetlink_net_ops = { 797 .init = nfnetlink_net_init, 798 .exit_batch = nfnetlink_net_exit_batch, 799 .id = &nfnetlink_pernet_id, 800 .size = sizeof(struct nfnl_net), 801 }; 802 803 static int __init nfnetlink_init(void) 804 { 805 int i; 806 807 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++) 808 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE); 809 810 for (i=0; i<NFNL_SUBSYS_COUNT; i++) 811 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]); 812 813 return register_pernet_subsys(&nfnetlink_net_ops); 814 } 815 816 static void __exit nfnetlink_exit(void) 817 { 818 unregister_pernet_subsys(&nfnetlink_net_ops); 819 } 820 module_init(nfnetlink_init); 821 module_exit(nfnetlink_exit); 822