1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * NETLINK Generic Netlink Family 4 * 5 * Authors: Jamal Hadi Salim 6 * Thomas Graf <tgraf@suug.ch> 7 * Johannes Berg <johannes@sipsolutions.net> 8 */ 9 10 #include <linux/module.h> 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/errno.h> 14 #include <linux/types.h> 15 #include <linux/socket.h> 16 #include <linux/string.h> 17 #include <linux/skbuff.h> 18 #include <linux/mutex.h> 19 #include <linux/bitmap.h> 20 #include <linux/rwsem.h> 21 #include <linux/idr.h> 22 #include <net/sock.h> 23 #include <net/genetlink.h> 24 25 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ 26 static DECLARE_RWSEM(cb_lock); 27 28 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); 29 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); 30 31 void genl_lock(void) 32 { 33 mutex_lock(&genl_mutex); 34 } 35 EXPORT_SYMBOL(genl_lock); 36 37 void genl_unlock(void) 38 { 39 mutex_unlock(&genl_mutex); 40 } 41 EXPORT_SYMBOL(genl_unlock); 42 43 #ifdef CONFIG_LOCKDEP 44 bool lockdep_genl_is_held(void) 45 { 46 return lockdep_is_held(&genl_mutex); 47 } 48 EXPORT_SYMBOL(lockdep_genl_is_held); 49 #endif 50 51 static void genl_lock_all(void) 52 { 53 down_write(&cb_lock); 54 genl_lock(); 55 } 56 57 static void genl_unlock_all(void) 58 { 59 genl_unlock(); 60 up_write(&cb_lock); 61 } 62 63 static DEFINE_IDR(genl_fam_idr); 64 65 /* 66 * Bitmap of multicast groups that are currently in use. 67 * 68 * To avoid an allocation at boot of just one unsigned long, 69 * declare it global instead. 70 * Bit 0 is marked as already used since group 0 is invalid. 71 * Bit 1 is marked as already used since the drop-monitor code 72 * abuses the API and thinks it can statically use group 1. 73 * That group will typically conflict with other groups that 74 * any proper users use. 75 * Bit 16 is marked as used since it's used for generic netlink 76 * and the code no longer marks pre-reserved IDs as used. 77 * Bit 17 is marked as already used since the VFS quota code 78 * also abused this API and relied on family == group ID, we 79 * cater to that by giving it a static family and group ID. 80 * Bit 18 is marked as already used since the PMCRAID driver 81 * did the same thing as the VFS quota code (maybe copied?) 82 */ 83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | 84 BIT(GENL_ID_VFS_DQUOT) | 85 BIT(GENL_ID_PMCRAID); 86 static unsigned long *mc_groups = &mc_group_start; 87 static unsigned long mc_groups_longs = 1; 88 89 static int genl_ctrl_event(int event, const struct genl_family *family, 90 const struct genl_multicast_group *grp, 91 int grp_id); 92 93 static const struct genl_family *genl_family_find_byid(unsigned int id) 94 { 95 return idr_find(&genl_fam_idr, id); 96 } 97 98 static const struct genl_family *genl_family_find_byname(char *name) 99 { 100 const struct genl_family *family; 101 unsigned int id; 102 103 idr_for_each_entry(&genl_fam_idr, family, id) 104 if (strcmp(family->name, name) == 0) 105 return family; 106 107 return NULL; 108 } 109 110 static const struct genl_ops *genl_get_cmd(u8 cmd, 111 const struct genl_family *family) 112 { 113 int i; 114 115 for (i = 0; i < family->n_ops; i++) 116 if (family->ops[i].cmd == cmd) 117 return &family->ops[i]; 118 119 return NULL; 120 } 121 122 static int genl_allocate_reserve_groups(int n_groups, int *first_id) 123 { 124 unsigned long *new_groups; 125 int start = 0; 126 int i; 127 int id; 128 bool fits; 129 130 do { 131 if (start == 0) 132 id = find_first_zero_bit(mc_groups, 133 mc_groups_longs * 134 BITS_PER_LONG); 135 else 136 id = find_next_zero_bit(mc_groups, 137 mc_groups_longs * BITS_PER_LONG, 138 start); 139 140 fits = true; 141 for (i = id; 142 i < min_t(int, id + n_groups, 143 mc_groups_longs * BITS_PER_LONG); 144 i++) { 145 if (test_bit(i, mc_groups)) { 146 start = i; 147 fits = false; 148 break; 149 } 150 } 151 152 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { 153 unsigned long new_longs = mc_groups_longs + 154 BITS_TO_LONGS(n_groups); 155 size_t nlen = new_longs * sizeof(unsigned long); 156 157 if (mc_groups == &mc_group_start) { 158 new_groups = kzalloc(nlen, GFP_KERNEL); 159 if (!new_groups) 160 return -ENOMEM; 161 mc_groups = new_groups; 162 *mc_groups = mc_group_start; 163 } else { 164 new_groups = krealloc(mc_groups, nlen, 165 GFP_KERNEL); 166 if (!new_groups) 167 return -ENOMEM; 168 mc_groups = new_groups; 169 for (i = 0; i < BITS_TO_LONGS(n_groups); i++) 170 mc_groups[mc_groups_longs + i] = 0; 171 } 172 mc_groups_longs = new_longs; 173 } 174 } while (!fits); 175 176 for (i = id; i < id + n_groups; i++) 177 set_bit(i, mc_groups); 178 *first_id = id; 179 return 0; 180 } 181 182 static struct genl_family genl_ctrl; 183 184 static int genl_validate_assign_mc_groups(struct genl_family *family) 185 { 186 int first_id; 187 int n_groups = family->n_mcgrps; 188 int err = 0, i; 189 bool groups_allocated = false; 190 191 if (!n_groups) 192 return 0; 193 194 for (i = 0; i < n_groups; i++) { 195 const struct genl_multicast_group *grp = &family->mcgrps[i]; 196 197 if (WARN_ON(grp->name[0] == '\0')) 198 return -EINVAL; 199 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) 200 return -EINVAL; 201 } 202 203 /* special-case our own group and hacks */ 204 if (family == &genl_ctrl) { 205 first_id = GENL_ID_CTRL; 206 BUG_ON(n_groups != 1); 207 } else if (strcmp(family->name, "NET_DM") == 0) { 208 first_id = 1; 209 BUG_ON(n_groups != 1); 210 } else if (family->id == GENL_ID_VFS_DQUOT) { 211 first_id = GENL_ID_VFS_DQUOT; 212 BUG_ON(n_groups != 1); 213 } else if (family->id == GENL_ID_PMCRAID) { 214 first_id = GENL_ID_PMCRAID; 215 BUG_ON(n_groups != 1); 216 } else { 217 groups_allocated = true; 218 err = genl_allocate_reserve_groups(n_groups, &first_id); 219 if (err) 220 return err; 221 } 222 223 family->mcgrp_offset = first_id; 224 225 /* if still initializing, can't and don't need to to realloc bitmaps */ 226 if (!init_net.genl_sock) 227 return 0; 228 229 if (family->netnsok) { 230 struct net *net; 231 232 netlink_table_grab(); 233 rcu_read_lock(); 234 for_each_net_rcu(net) { 235 err = __netlink_change_ngroups(net->genl_sock, 236 mc_groups_longs * BITS_PER_LONG); 237 if (err) { 238 /* 239 * No need to roll back, can only fail if 240 * memory allocation fails and then the 241 * number of _possible_ groups has been 242 * increased on some sockets which is ok. 243 */ 244 break; 245 } 246 } 247 rcu_read_unlock(); 248 netlink_table_ungrab(); 249 } else { 250 err = netlink_change_ngroups(init_net.genl_sock, 251 mc_groups_longs * BITS_PER_LONG); 252 } 253 254 if (groups_allocated && err) { 255 for (i = 0; i < family->n_mcgrps; i++) 256 clear_bit(family->mcgrp_offset + i, mc_groups); 257 } 258 259 return err; 260 } 261 262 static void genl_unregister_mc_groups(const struct genl_family *family) 263 { 264 struct net *net; 265 int i; 266 267 netlink_table_grab(); 268 rcu_read_lock(); 269 for_each_net_rcu(net) { 270 for (i = 0; i < family->n_mcgrps; i++) 271 __netlink_clear_multicast_users( 272 net->genl_sock, family->mcgrp_offset + i); 273 } 274 rcu_read_unlock(); 275 netlink_table_ungrab(); 276 277 for (i = 0; i < family->n_mcgrps; i++) { 278 int grp_id = family->mcgrp_offset + i; 279 280 if (grp_id != 1) 281 clear_bit(grp_id, mc_groups); 282 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, 283 &family->mcgrps[i], grp_id); 284 } 285 } 286 287 static int genl_validate_ops(const struct genl_family *family) 288 { 289 const struct genl_ops *ops = family->ops; 290 unsigned int n_ops = family->n_ops; 291 int i, j; 292 293 if (WARN_ON(n_ops && !ops)) 294 return -EINVAL; 295 296 if (!n_ops) 297 return 0; 298 299 for (i = 0; i < n_ops; i++) { 300 if (ops[i].dumpit == NULL && ops[i].doit == NULL) 301 return -EINVAL; 302 for (j = i + 1; j < n_ops; j++) 303 if (ops[i].cmd == ops[j].cmd) 304 return -EINVAL; 305 } 306 307 return 0; 308 } 309 310 /** 311 * genl_register_family - register a generic netlink family 312 * @family: generic netlink family 313 * 314 * Registers the specified family after validating it first. Only one 315 * family may be registered with the same family name or identifier. 316 * 317 * The family's ops, multicast groups and module pointer must already 318 * be assigned. 319 * 320 * Return 0 on success or a negative error code. 321 */ 322 int genl_register_family(struct genl_family *family) 323 { 324 int err, i; 325 int start = GENL_START_ALLOC, end = GENL_MAX_ID; 326 327 err = genl_validate_ops(family); 328 if (err) 329 return err; 330 331 genl_lock_all(); 332 333 if (genl_family_find_byname(family->name)) { 334 err = -EEXIST; 335 goto errout_locked; 336 } 337 338 /* 339 * Sadly, a few cases need to be special-cased 340 * due to them having previously abused the API 341 * and having used their family ID also as their 342 * multicast group ID, so we use reserved IDs 343 * for both to be sure we can do that mapping. 344 */ 345 if (family == &genl_ctrl) { 346 /* and this needs to be special for initial family lookups */ 347 start = end = GENL_ID_CTRL; 348 } else if (strcmp(family->name, "pmcraid") == 0) { 349 start = end = GENL_ID_PMCRAID; 350 } else if (strcmp(family->name, "VFS_DQUOT") == 0) { 351 start = end = GENL_ID_VFS_DQUOT; 352 } 353 354 if (family->maxattr && !family->parallel_ops) { 355 family->attrbuf = kmalloc_array(family->maxattr + 1, 356 sizeof(struct nlattr *), 357 GFP_KERNEL); 358 if (family->attrbuf == NULL) { 359 err = -ENOMEM; 360 goto errout_locked; 361 } 362 } else 363 family->attrbuf = NULL; 364 365 family->id = idr_alloc_cyclic(&genl_fam_idr, family, 366 start, end + 1, GFP_KERNEL); 367 if (family->id < 0) { 368 err = family->id; 369 goto errout_free; 370 } 371 372 err = genl_validate_assign_mc_groups(family); 373 if (err) 374 goto errout_remove; 375 376 genl_unlock_all(); 377 378 /* send all events */ 379 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); 380 for (i = 0; i < family->n_mcgrps; i++) 381 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, 382 &family->mcgrps[i], family->mcgrp_offset + i); 383 384 return 0; 385 386 errout_remove: 387 idr_remove(&genl_fam_idr, family->id); 388 errout_free: 389 kfree(family->attrbuf); 390 errout_locked: 391 genl_unlock_all(); 392 return err; 393 } 394 EXPORT_SYMBOL(genl_register_family); 395 396 /** 397 * genl_unregister_family - unregister generic netlink family 398 * @family: generic netlink family 399 * 400 * Unregisters the specified family. 401 * 402 * Returns 0 on success or a negative error code. 403 */ 404 int genl_unregister_family(const struct genl_family *family) 405 { 406 genl_lock_all(); 407 408 if (!genl_family_find_byid(family->id)) { 409 genl_unlock_all(); 410 return -ENOENT; 411 } 412 413 genl_unregister_mc_groups(family); 414 415 idr_remove(&genl_fam_idr, family->id); 416 417 up_write(&cb_lock); 418 wait_event(genl_sk_destructing_waitq, 419 atomic_read(&genl_sk_destructing_cnt) == 0); 420 genl_unlock(); 421 422 kfree(family->attrbuf); 423 424 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); 425 426 return 0; 427 } 428 EXPORT_SYMBOL(genl_unregister_family); 429 430 /** 431 * genlmsg_put - Add generic netlink header to netlink message 432 * @skb: socket buffer holding the message 433 * @portid: netlink portid the message is addressed to 434 * @seq: sequence number (usually the one of the sender) 435 * @family: generic netlink family 436 * @flags: netlink message flags 437 * @cmd: generic netlink command 438 * 439 * Returns pointer to user specific header 440 */ 441 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 442 const struct genl_family *family, int flags, u8 cmd) 443 { 444 struct nlmsghdr *nlh; 445 struct genlmsghdr *hdr; 446 447 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 448 family->hdrsize, flags); 449 if (nlh == NULL) 450 return NULL; 451 452 hdr = nlmsg_data(nlh); 453 hdr->cmd = cmd; 454 hdr->version = family->version; 455 hdr->reserved = 0; 456 457 return (char *) hdr + GENL_HDRLEN; 458 } 459 EXPORT_SYMBOL(genlmsg_put); 460 461 static struct genl_dumpit_info *genl_dumpit_info_alloc(void) 462 { 463 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL); 464 } 465 466 static void genl_dumpit_info_free(const struct genl_dumpit_info *info) 467 { 468 kfree(info); 469 } 470 471 static struct nlattr ** 472 genl_family_rcv_msg_attrs_parse(const struct genl_family *family, 473 struct nlmsghdr *nlh, 474 struct netlink_ext_ack *extack, 475 const struct genl_ops *ops, 476 int hdrlen, 477 enum genl_validate_flags no_strict_flag, 478 bool parallel) 479 { 480 enum netlink_validation validate = ops->validate & no_strict_flag ? 481 NL_VALIDATE_LIBERAL : 482 NL_VALIDATE_STRICT; 483 struct nlattr **attrbuf; 484 int err; 485 486 if (!family->maxattr) 487 return NULL; 488 489 if (parallel) { 490 attrbuf = kmalloc_array(family->maxattr + 1, 491 sizeof(struct nlattr *), GFP_KERNEL); 492 if (!attrbuf) 493 return ERR_PTR(-ENOMEM); 494 } else { 495 attrbuf = family->attrbuf; 496 } 497 498 err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, 499 family->policy, validate, extack); 500 if (err && parallel) { 501 kfree(attrbuf); 502 return ERR_PTR(err); 503 } 504 return attrbuf; 505 } 506 507 static void genl_family_rcv_msg_attrs_free(const struct genl_family *family, 508 struct nlattr **attrbuf, 509 bool parallel) 510 { 511 if (parallel) 512 kfree(attrbuf); 513 } 514 515 static int genl_lock_start(struct netlink_callback *cb) 516 { 517 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 518 int rc = 0; 519 520 if (ops->start) { 521 genl_lock(); 522 rc = ops->start(cb); 523 genl_unlock(); 524 } 525 return rc; 526 } 527 528 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 529 { 530 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 531 int rc; 532 533 genl_lock(); 534 rc = ops->dumpit(skb, cb); 535 genl_unlock(); 536 return rc; 537 } 538 539 static int genl_lock_done(struct netlink_callback *cb) 540 { 541 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 542 const struct genl_ops *ops = info->ops; 543 int rc = 0; 544 545 if (ops->done) { 546 genl_lock(); 547 rc = ops->done(cb); 548 genl_unlock(); 549 } 550 genl_family_rcv_msg_attrs_free(info->family, info->attrs, true); 551 genl_dumpit_info_free(info); 552 return rc; 553 } 554 555 static int genl_parallel_done(struct netlink_callback *cb) 556 { 557 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 558 const struct genl_ops *ops = info->ops; 559 int rc = 0; 560 561 if (ops->done) 562 rc = ops->done(cb); 563 genl_family_rcv_msg_attrs_free(info->family, info->attrs, true); 564 genl_dumpit_info_free(info); 565 return rc; 566 } 567 568 static int genl_family_rcv_msg_dumpit(const struct genl_family *family, 569 struct sk_buff *skb, 570 struct nlmsghdr *nlh, 571 struct netlink_ext_ack *extack, 572 const struct genl_ops *ops, 573 int hdrlen, struct net *net) 574 { 575 struct genl_dumpit_info *info; 576 struct nlattr **attrs = NULL; 577 int err; 578 579 if (!ops->dumpit) 580 return -EOPNOTSUPP; 581 582 if (ops->validate & GENL_DONT_VALIDATE_DUMP) 583 goto no_attrs; 584 585 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 586 return -EINVAL; 587 588 attrs = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 589 ops, hdrlen, 590 GENL_DONT_VALIDATE_DUMP_STRICT, 591 true); 592 if (IS_ERR(attrs)) 593 return PTR_ERR(attrs); 594 595 no_attrs: 596 /* Allocate dumpit info. It is going to be freed by done() callback. */ 597 info = genl_dumpit_info_alloc(); 598 if (!info) { 599 genl_family_rcv_msg_attrs_free(family, attrs, true); 600 return -ENOMEM; 601 } 602 603 info->family = family; 604 info->ops = ops; 605 info->attrs = attrs; 606 607 if (!family->parallel_ops) { 608 struct netlink_dump_control c = { 609 .module = family->module, 610 .data = info, 611 .start = genl_lock_start, 612 .dump = genl_lock_dumpit, 613 .done = genl_lock_done, 614 }; 615 616 genl_unlock(); 617 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 618 genl_lock(); 619 620 } else { 621 struct netlink_dump_control c = { 622 .module = family->module, 623 .data = info, 624 .start = ops->start, 625 .dump = ops->dumpit, 626 .done = genl_parallel_done, 627 }; 628 629 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 630 } 631 632 return err; 633 } 634 635 static int genl_family_rcv_msg_doit(const struct genl_family *family, 636 struct sk_buff *skb, 637 struct nlmsghdr *nlh, 638 struct netlink_ext_ack *extack, 639 const struct genl_ops *ops, 640 int hdrlen, struct net *net) 641 { 642 struct nlattr **attrbuf; 643 struct genl_info info; 644 int err; 645 646 if (!ops->doit) 647 return -EOPNOTSUPP; 648 649 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 650 ops, hdrlen, 651 GENL_DONT_VALIDATE_STRICT, 652 family->parallel_ops); 653 if (IS_ERR(attrbuf)) 654 return PTR_ERR(attrbuf); 655 656 info.snd_seq = nlh->nlmsg_seq; 657 info.snd_portid = NETLINK_CB(skb).portid; 658 info.nlhdr = nlh; 659 info.genlhdr = nlmsg_data(nlh); 660 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 661 info.attrs = attrbuf; 662 info.extack = extack; 663 genl_info_net_set(&info, net); 664 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 665 666 if (family->pre_doit) { 667 err = family->pre_doit(ops, skb, &info); 668 if (err) 669 goto out; 670 } 671 672 err = ops->doit(skb, &info); 673 674 if (family->post_doit) 675 family->post_doit(ops, skb, &info); 676 677 out: 678 genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops); 679 680 return err; 681 } 682 683 static int genl_family_rcv_msg(const struct genl_family *family, 684 struct sk_buff *skb, 685 struct nlmsghdr *nlh, 686 struct netlink_ext_ack *extack) 687 { 688 const struct genl_ops *ops; 689 struct net *net = sock_net(skb->sk); 690 struct genlmsghdr *hdr = nlmsg_data(nlh); 691 int hdrlen; 692 693 /* this family doesn't exist in this netns */ 694 if (!family->netnsok && !net_eq(net, &init_net)) 695 return -ENOENT; 696 697 hdrlen = GENL_HDRLEN + family->hdrsize; 698 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 699 return -EINVAL; 700 701 ops = genl_get_cmd(hdr->cmd, family); 702 if (ops == NULL) 703 return -EOPNOTSUPP; 704 705 if ((ops->flags & GENL_ADMIN_PERM) && 706 !netlink_capable(skb, CAP_NET_ADMIN)) 707 return -EPERM; 708 709 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 710 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 711 return -EPERM; 712 713 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) 714 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, 715 ops, hdrlen, net); 716 else 717 return genl_family_rcv_msg_doit(family, skb, nlh, extack, 718 ops, hdrlen, net); 719 } 720 721 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 722 struct netlink_ext_ack *extack) 723 { 724 const struct genl_family *family; 725 int err; 726 727 family = genl_family_find_byid(nlh->nlmsg_type); 728 if (family == NULL) 729 return -ENOENT; 730 731 if (!family->parallel_ops) 732 genl_lock(); 733 734 err = genl_family_rcv_msg(family, skb, nlh, extack); 735 736 if (!family->parallel_ops) 737 genl_unlock(); 738 739 return err; 740 } 741 742 static void genl_rcv(struct sk_buff *skb) 743 { 744 down_read(&cb_lock); 745 netlink_rcv_skb(skb, &genl_rcv_msg); 746 up_read(&cb_lock); 747 } 748 749 /************************************************************************** 750 * Controller 751 **************************************************************************/ 752 753 static struct genl_family genl_ctrl; 754 755 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 756 u32 flags, struct sk_buff *skb, u8 cmd) 757 { 758 void *hdr; 759 760 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 761 if (hdr == NULL) 762 return -1; 763 764 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 765 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 766 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 767 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 768 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 769 goto nla_put_failure; 770 771 if (family->n_ops) { 772 struct nlattr *nla_ops; 773 int i; 774 775 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS); 776 if (nla_ops == NULL) 777 goto nla_put_failure; 778 779 for (i = 0; i < family->n_ops; i++) { 780 struct nlattr *nest; 781 const struct genl_ops *ops = &family->ops[i]; 782 u32 op_flags = ops->flags; 783 784 if (ops->dumpit) 785 op_flags |= GENL_CMD_CAP_DUMP; 786 if (ops->doit) 787 op_flags |= GENL_CMD_CAP_DO; 788 if (family->policy) 789 op_flags |= GENL_CMD_CAP_HASPOL; 790 791 nest = nla_nest_start_noflag(skb, i + 1); 792 if (nest == NULL) 793 goto nla_put_failure; 794 795 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 796 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 797 goto nla_put_failure; 798 799 nla_nest_end(skb, nest); 800 } 801 802 nla_nest_end(skb, nla_ops); 803 } 804 805 if (family->n_mcgrps) { 806 struct nlattr *nla_grps; 807 int i; 808 809 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 810 if (nla_grps == NULL) 811 goto nla_put_failure; 812 813 for (i = 0; i < family->n_mcgrps; i++) { 814 struct nlattr *nest; 815 const struct genl_multicast_group *grp; 816 817 grp = &family->mcgrps[i]; 818 819 nest = nla_nest_start_noflag(skb, i + 1); 820 if (nest == NULL) 821 goto nla_put_failure; 822 823 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 824 family->mcgrp_offset + i) || 825 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 826 grp->name)) 827 goto nla_put_failure; 828 829 nla_nest_end(skb, nest); 830 } 831 nla_nest_end(skb, nla_grps); 832 } 833 834 genlmsg_end(skb, hdr); 835 return 0; 836 837 nla_put_failure: 838 genlmsg_cancel(skb, hdr); 839 return -EMSGSIZE; 840 } 841 842 static int ctrl_fill_mcgrp_info(const struct genl_family *family, 843 const struct genl_multicast_group *grp, 844 int grp_id, u32 portid, u32 seq, u32 flags, 845 struct sk_buff *skb, u8 cmd) 846 { 847 void *hdr; 848 struct nlattr *nla_grps; 849 struct nlattr *nest; 850 851 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 852 if (hdr == NULL) 853 return -1; 854 855 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 856 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 857 goto nla_put_failure; 858 859 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 860 if (nla_grps == NULL) 861 goto nla_put_failure; 862 863 nest = nla_nest_start_noflag(skb, 1); 864 if (nest == NULL) 865 goto nla_put_failure; 866 867 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 868 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 869 grp->name)) 870 goto nla_put_failure; 871 872 nla_nest_end(skb, nest); 873 nla_nest_end(skb, nla_grps); 874 875 genlmsg_end(skb, hdr); 876 return 0; 877 878 nla_put_failure: 879 genlmsg_cancel(skb, hdr); 880 return -EMSGSIZE; 881 } 882 883 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 884 { 885 int n = 0; 886 struct genl_family *rt; 887 struct net *net = sock_net(skb->sk); 888 int fams_to_skip = cb->args[0]; 889 unsigned int id; 890 891 idr_for_each_entry(&genl_fam_idr, rt, id) { 892 if (!rt->netnsok && !net_eq(net, &init_net)) 893 continue; 894 895 if (n++ < fams_to_skip) 896 continue; 897 898 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 899 cb->nlh->nlmsg_seq, NLM_F_MULTI, 900 skb, CTRL_CMD_NEWFAMILY) < 0) { 901 n--; 902 break; 903 } 904 } 905 906 cb->args[0] = n; 907 return skb->len; 908 } 909 910 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, 911 u32 portid, int seq, u8 cmd) 912 { 913 struct sk_buff *skb; 914 int err; 915 916 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 917 if (skb == NULL) 918 return ERR_PTR(-ENOBUFS); 919 920 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 921 if (err < 0) { 922 nlmsg_free(skb); 923 return ERR_PTR(err); 924 } 925 926 return skb; 927 } 928 929 static struct sk_buff * 930 ctrl_build_mcgrp_msg(const struct genl_family *family, 931 const struct genl_multicast_group *grp, 932 int grp_id, u32 portid, int seq, u8 cmd) 933 { 934 struct sk_buff *skb; 935 int err; 936 937 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 938 if (skb == NULL) 939 return ERR_PTR(-ENOBUFS); 940 941 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 942 seq, 0, skb, cmd); 943 if (err < 0) { 944 nlmsg_free(skb); 945 return ERR_PTR(err); 946 } 947 948 return skb; 949 } 950 951 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 952 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 953 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 954 .len = GENL_NAMSIZ - 1 }, 955 }; 956 957 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 958 { 959 struct sk_buff *msg; 960 const struct genl_family *res = NULL; 961 int err = -EINVAL; 962 963 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 964 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 965 res = genl_family_find_byid(id); 966 err = -ENOENT; 967 } 968 969 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 970 char *name; 971 972 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 973 res = genl_family_find_byname(name); 974 #ifdef CONFIG_MODULES 975 if (res == NULL) { 976 genl_unlock(); 977 up_read(&cb_lock); 978 request_module("net-pf-%d-proto-%d-family-%s", 979 PF_NETLINK, NETLINK_GENERIC, name); 980 down_read(&cb_lock); 981 genl_lock(); 982 res = genl_family_find_byname(name); 983 } 984 #endif 985 err = -ENOENT; 986 } 987 988 if (res == NULL) 989 return err; 990 991 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 992 /* family doesn't exist here */ 993 return -ENOENT; 994 } 995 996 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 997 CTRL_CMD_NEWFAMILY); 998 if (IS_ERR(msg)) 999 return PTR_ERR(msg); 1000 1001 return genlmsg_reply(msg, info); 1002 } 1003 1004 static int genl_ctrl_event(int event, const struct genl_family *family, 1005 const struct genl_multicast_group *grp, 1006 int grp_id) 1007 { 1008 struct sk_buff *msg; 1009 1010 /* genl is still initialising */ 1011 if (!init_net.genl_sock) 1012 return 0; 1013 1014 switch (event) { 1015 case CTRL_CMD_NEWFAMILY: 1016 case CTRL_CMD_DELFAMILY: 1017 WARN_ON(grp); 1018 msg = ctrl_build_family_msg(family, 0, 0, event); 1019 break; 1020 case CTRL_CMD_NEWMCAST_GRP: 1021 case CTRL_CMD_DELMCAST_GRP: 1022 BUG_ON(!grp); 1023 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 1024 break; 1025 default: 1026 return -EINVAL; 1027 } 1028 1029 if (IS_ERR(msg)) 1030 return PTR_ERR(msg); 1031 1032 if (!family->netnsok) { 1033 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 1034 0, GFP_KERNEL); 1035 } else { 1036 rcu_read_lock(); 1037 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 1038 0, GFP_ATOMIC); 1039 rcu_read_unlock(); 1040 } 1041 1042 return 0; 1043 } 1044 1045 static const struct genl_ops genl_ctrl_ops[] = { 1046 { 1047 .cmd = CTRL_CMD_GETFAMILY, 1048 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1049 .doit = ctrl_getfamily, 1050 .dumpit = ctrl_dumpfamily, 1051 }, 1052 }; 1053 1054 static const struct genl_multicast_group genl_ctrl_groups[] = { 1055 { .name = "notify", }, 1056 }; 1057 1058 static struct genl_family genl_ctrl __ro_after_init = { 1059 .module = THIS_MODULE, 1060 .ops = genl_ctrl_ops, 1061 .n_ops = ARRAY_SIZE(genl_ctrl_ops), 1062 .mcgrps = genl_ctrl_groups, 1063 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), 1064 .id = GENL_ID_CTRL, 1065 .name = "nlctrl", 1066 .version = 0x2, 1067 .maxattr = CTRL_ATTR_MAX, 1068 .policy = ctrl_policy, 1069 .netnsok = true, 1070 }; 1071 1072 static int genl_bind(struct net *net, int group) 1073 { 1074 struct genl_family *f; 1075 int err = -ENOENT; 1076 unsigned int id; 1077 1078 down_read(&cb_lock); 1079 1080 idr_for_each_entry(&genl_fam_idr, f, id) { 1081 if (group >= f->mcgrp_offset && 1082 group < f->mcgrp_offset + f->n_mcgrps) { 1083 int fam_grp = group - f->mcgrp_offset; 1084 1085 if (!f->netnsok && net != &init_net) 1086 err = -ENOENT; 1087 else if (f->mcast_bind) 1088 err = f->mcast_bind(net, fam_grp); 1089 else 1090 err = 0; 1091 break; 1092 } 1093 } 1094 up_read(&cb_lock); 1095 1096 return err; 1097 } 1098 1099 static void genl_unbind(struct net *net, int group) 1100 { 1101 struct genl_family *f; 1102 unsigned int id; 1103 1104 down_read(&cb_lock); 1105 1106 idr_for_each_entry(&genl_fam_idr, f, id) { 1107 if (group >= f->mcgrp_offset && 1108 group < f->mcgrp_offset + f->n_mcgrps) { 1109 int fam_grp = group - f->mcgrp_offset; 1110 1111 if (f->mcast_unbind) 1112 f->mcast_unbind(net, fam_grp); 1113 break; 1114 } 1115 } 1116 up_read(&cb_lock); 1117 } 1118 1119 static int __net_init genl_pernet_init(struct net *net) 1120 { 1121 struct netlink_kernel_cfg cfg = { 1122 .input = genl_rcv, 1123 .flags = NL_CFG_F_NONROOT_RECV, 1124 .bind = genl_bind, 1125 .unbind = genl_unbind, 1126 }; 1127 1128 /* we'll bump the group number right afterwards */ 1129 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1130 1131 if (!net->genl_sock && net_eq(net, &init_net)) 1132 panic("GENL: Cannot initialize generic netlink\n"); 1133 1134 if (!net->genl_sock) 1135 return -ENOMEM; 1136 1137 return 0; 1138 } 1139 1140 static void __net_exit genl_pernet_exit(struct net *net) 1141 { 1142 netlink_kernel_release(net->genl_sock); 1143 net->genl_sock = NULL; 1144 } 1145 1146 static struct pernet_operations genl_pernet_ops = { 1147 .init = genl_pernet_init, 1148 .exit = genl_pernet_exit, 1149 }; 1150 1151 static int __init genl_init(void) 1152 { 1153 int err; 1154 1155 err = genl_register_family(&genl_ctrl); 1156 if (err < 0) 1157 goto problem; 1158 1159 err = register_pernet_subsys(&genl_pernet_ops); 1160 if (err) 1161 goto problem; 1162 1163 return 0; 1164 1165 problem: 1166 panic("GENL: Cannot register controller: %d\n", err); 1167 } 1168 1169 subsys_initcall(genl_init); 1170 1171 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1172 gfp_t flags) 1173 { 1174 struct sk_buff *tmp; 1175 struct net *net, *prev = NULL; 1176 bool delivered = false; 1177 int err; 1178 1179 for_each_net_rcu(net) { 1180 if (prev) { 1181 tmp = skb_clone(skb, flags); 1182 if (!tmp) { 1183 err = -ENOMEM; 1184 goto error; 1185 } 1186 err = nlmsg_multicast(prev->genl_sock, tmp, 1187 portid, group, flags); 1188 if (!err) 1189 delivered = true; 1190 else if (err != -ESRCH) 1191 goto error; 1192 } 1193 1194 prev = net; 1195 } 1196 1197 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1198 if (!err) 1199 delivered = true; 1200 else if (err != -ESRCH) 1201 return err; 1202 return delivered ? 0 : -ESRCH; 1203 error: 1204 kfree_skb(skb); 1205 return err; 1206 } 1207 1208 int genlmsg_multicast_allns(const struct genl_family *family, 1209 struct sk_buff *skb, u32 portid, 1210 unsigned int group, gfp_t flags) 1211 { 1212 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1213 return -EINVAL; 1214 group = family->mcgrp_offset + group; 1215 return genlmsg_mcast(skb, portid, group, flags); 1216 } 1217 EXPORT_SYMBOL(genlmsg_multicast_allns); 1218 1219 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 1220 struct genl_info *info, u32 group, gfp_t flags) 1221 { 1222 struct net *net = genl_info_net(info); 1223 struct sock *sk = net->genl_sock; 1224 int report = 0; 1225 1226 if (info->nlhdr) 1227 report = nlmsg_report(info->nlhdr); 1228 1229 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1230 return; 1231 group = family->mcgrp_offset + group; 1232 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1233 } 1234 EXPORT_SYMBOL(genl_notify); 1235