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) { 501 if (parallel) 502 kfree(attrbuf); 503 return ERR_PTR(err); 504 } 505 return attrbuf; 506 } 507 508 static void genl_family_rcv_msg_attrs_free(const struct genl_family *family, 509 struct nlattr **attrbuf, 510 bool parallel) 511 { 512 if (parallel) 513 kfree(attrbuf); 514 } 515 516 static int genl_lock_start(struct netlink_callback *cb) 517 { 518 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 519 int rc = 0; 520 521 if (ops->start) { 522 genl_lock(); 523 rc = ops->start(cb); 524 genl_unlock(); 525 } 526 return rc; 527 } 528 529 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 530 { 531 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 532 int rc; 533 534 genl_lock(); 535 rc = ops->dumpit(skb, cb); 536 genl_unlock(); 537 return rc; 538 } 539 540 static int genl_lock_done(struct netlink_callback *cb) 541 { 542 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 543 const struct genl_ops *ops = info->ops; 544 int rc = 0; 545 546 if (ops->done) { 547 genl_lock(); 548 rc = ops->done(cb); 549 genl_unlock(); 550 } 551 genl_family_rcv_msg_attrs_free(info->family, info->attrs, true); 552 genl_dumpit_info_free(info); 553 return rc; 554 } 555 556 static int genl_parallel_done(struct netlink_callback *cb) 557 { 558 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 559 const struct genl_ops *ops = info->ops; 560 int rc = 0; 561 562 if (ops->done) 563 rc = ops->done(cb); 564 genl_family_rcv_msg_attrs_free(info->family, info->attrs, true); 565 genl_dumpit_info_free(info); 566 return rc; 567 } 568 569 static int genl_family_rcv_msg_dumpit(const struct genl_family *family, 570 struct sk_buff *skb, 571 struct nlmsghdr *nlh, 572 struct netlink_ext_ack *extack, 573 const struct genl_ops *ops, 574 int hdrlen, struct net *net) 575 { 576 struct genl_dumpit_info *info; 577 struct nlattr **attrs = NULL; 578 int err; 579 580 if (!ops->dumpit) 581 return -EOPNOTSUPP; 582 583 if (ops->validate & GENL_DONT_VALIDATE_DUMP) 584 goto no_attrs; 585 586 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 587 return -EINVAL; 588 589 attrs = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 590 ops, hdrlen, 591 GENL_DONT_VALIDATE_DUMP_STRICT, 592 true); 593 if (IS_ERR(attrs)) 594 return PTR_ERR(attrs); 595 596 no_attrs: 597 /* Allocate dumpit info. It is going to be freed by done() callback. */ 598 info = genl_dumpit_info_alloc(); 599 if (!info) { 600 genl_family_rcv_msg_attrs_free(family, attrs, true); 601 return -ENOMEM; 602 } 603 604 info->family = family; 605 info->ops = ops; 606 info->attrs = attrs; 607 608 if (!family->parallel_ops) { 609 struct netlink_dump_control c = { 610 .module = family->module, 611 .data = info, 612 .start = genl_lock_start, 613 .dump = genl_lock_dumpit, 614 .done = genl_lock_done, 615 }; 616 617 genl_unlock(); 618 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 619 genl_lock(); 620 621 } else { 622 struct netlink_dump_control c = { 623 .module = family->module, 624 .data = info, 625 .start = ops->start, 626 .dump = ops->dumpit, 627 .done = genl_parallel_done, 628 }; 629 630 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 631 } 632 633 return err; 634 } 635 636 static int genl_family_rcv_msg_doit(const struct genl_family *family, 637 struct sk_buff *skb, 638 struct nlmsghdr *nlh, 639 struct netlink_ext_ack *extack, 640 const struct genl_ops *ops, 641 int hdrlen, struct net *net) 642 { 643 struct nlattr **attrbuf; 644 struct genl_info info; 645 int err; 646 647 if (!ops->doit) 648 return -EOPNOTSUPP; 649 650 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 651 ops, hdrlen, 652 GENL_DONT_VALIDATE_STRICT, 653 family->parallel_ops); 654 if (IS_ERR(attrbuf)) 655 return PTR_ERR(attrbuf); 656 657 info.snd_seq = nlh->nlmsg_seq; 658 info.snd_portid = NETLINK_CB(skb).portid; 659 info.nlhdr = nlh; 660 info.genlhdr = nlmsg_data(nlh); 661 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 662 info.attrs = attrbuf; 663 info.extack = extack; 664 genl_info_net_set(&info, net); 665 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 666 667 if (family->pre_doit) { 668 err = family->pre_doit(ops, skb, &info); 669 if (err) 670 goto out; 671 } 672 673 err = ops->doit(skb, &info); 674 675 if (family->post_doit) 676 family->post_doit(ops, skb, &info); 677 678 out: 679 genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops); 680 681 return err; 682 } 683 684 static int genl_family_rcv_msg(const struct genl_family *family, 685 struct sk_buff *skb, 686 struct nlmsghdr *nlh, 687 struct netlink_ext_ack *extack) 688 { 689 const struct genl_ops *ops; 690 struct net *net = sock_net(skb->sk); 691 struct genlmsghdr *hdr = nlmsg_data(nlh); 692 int hdrlen; 693 694 /* this family doesn't exist in this netns */ 695 if (!family->netnsok && !net_eq(net, &init_net)) 696 return -ENOENT; 697 698 hdrlen = GENL_HDRLEN + family->hdrsize; 699 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 700 return -EINVAL; 701 702 ops = genl_get_cmd(hdr->cmd, family); 703 if (ops == NULL) 704 return -EOPNOTSUPP; 705 706 if ((ops->flags & GENL_ADMIN_PERM) && 707 !netlink_capable(skb, CAP_NET_ADMIN)) 708 return -EPERM; 709 710 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 711 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 712 return -EPERM; 713 714 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) 715 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, 716 ops, hdrlen, net); 717 else 718 return genl_family_rcv_msg_doit(family, skb, nlh, extack, 719 ops, hdrlen, net); 720 } 721 722 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 723 struct netlink_ext_ack *extack) 724 { 725 const struct genl_family *family; 726 int err; 727 728 family = genl_family_find_byid(nlh->nlmsg_type); 729 if (family == NULL) 730 return -ENOENT; 731 732 if (!family->parallel_ops) 733 genl_lock(); 734 735 err = genl_family_rcv_msg(family, skb, nlh, extack); 736 737 if (!family->parallel_ops) 738 genl_unlock(); 739 740 return err; 741 } 742 743 static void genl_rcv(struct sk_buff *skb) 744 { 745 down_read(&cb_lock); 746 netlink_rcv_skb(skb, &genl_rcv_msg); 747 up_read(&cb_lock); 748 } 749 750 /************************************************************************** 751 * Controller 752 **************************************************************************/ 753 754 static struct genl_family genl_ctrl; 755 756 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 757 u32 flags, struct sk_buff *skb, u8 cmd) 758 { 759 void *hdr; 760 761 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 762 if (hdr == NULL) 763 return -1; 764 765 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 766 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 767 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 768 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 769 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 770 goto nla_put_failure; 771 772 if (family->n_ops) { 773 struct nlattr *nla_ops; 774 int i; 775 776 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS); 777 if (nla_ops == NULL) 778 goto nla_put_failure; 779 780 for (i = 0; i < family->n_ops; i++) { 781 struct nlattr *nest; 782 const struct genl_ops *ops = &family->ops[i]; 783 u32 op_flags = ops->flags; 784 785 if (ops->dumpit) 786 op_flags |= GENL_CMD_CAP_DUMP; 787 if (ops->doit) 788 op_flags |= GENL_CMD_CAP_DO; 789 if (family->policy) 790 op_flags |= GENL_CMD_CAP_HASPOL; 791 792 nest = nla_nest_start_noflag(skb, i + 1); 793 if (nest == NULL) 794 goto nla_put_failure; 795 796 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 797 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 798 goto nla_put_failure; 799 800 nla_nest_end(skb, nest); 801 } 802 803 nla_nest_end(skb, nla_ops); 804 } 805 806 if (family->n_mcgrps) { 807 struct nlattr *nla_grps; 808 int i; 809 810 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 811 if (nla_grps == NULL) 812 goto nla_put_failure; 813 814 for (i = 0; i < family->n_mcgrps; i++) { 815 struct nlattr *nest; 816 const struct genl_multicast_group *grp; 817 818 grp = &family->mcgrps[i]; 819 820 nest = nla_nest_start_noflag(skb, i + 1); 821 if (nest == NULL) 822 goto nla_put_failure; 823 824 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 825 family->mcgrp_offset + i) || 826 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 827 grp->name)) 828 goto nla_put_failure; 829 830 nla_nest_end(skb, nest); 831 } 832 nla_nest_end(skb, nla_grps); 833 } 834 835 genlmsg_end(skb, hdr); 836 return 0; 837 838 nla_put_failure: 839 genlmsg_cancel(skb, hdr); 840 return -EMSGSIZE; 841 } 842 843 static int ctrl_fill_mcgrp_info(const struct genl_family *family, 844 const struct genl_multicast_group *grp, 845 int grp_id, u32 portid, u32 seq, u32 flags, 846 struct sk_buff *skb, u8 cmd) 847 { 848 void *hdr; 849 struct nlattr *nla_grps; 850 struct nlattr *nest; 851 852 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 853 if (hdr == NULL) 854 return -1; 855 856 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 857 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 858 goto nla_put_failure; 859 860 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 861 if (nla_grps == NULL) 862 goto nla_put_failure; 863 864 nest = nla_nest_start_noflag(skb, 1); 865 if (nest == NULL) 866 goto nla_put_failure; 867 868 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 869 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 870 grp->name)) 871 goto nla_put_failure; 872 873 nla_nest_end(skb, nest); 874 nla_nest_end(skb, nla_grps); 875 876 genlmsg_end(skb, hdr); 877 return 0; 878 879 nla_put_failure: 880 genlmsg_cancel(skb, hdr); 881 return -EMSGSIZE; 882 } 883 884 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 885 { 886 int n = 0; 887 struct genl_family *rt; 888 struct net *net = sock_net(skb->sk); 889 int fams_to_skip = cb->args[0]; 890 unsigned int id; 891 892 idr_for_each_entry(&genl_fam_idr, rt, id) { 893 if (!rt->netnsok && !net_eq(net, &init_net)) 894 continue; 895 896 if (n++ < fams_to_skip) 897 continue; 898 899 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 900 cb->nlh->nlmsg_seq, NLM_F_MULTI, 901 skb, CTRL_CMD_NEWFAMILY) < 0) { 902 n--; 903 break; 904 } 905 } 906 907 cb->args[0] = n; 908 return skb->len; 909 } 910 911 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, 912 u32 portid, int seq, u8 cmd) 913 { 914 struct sk_buff *skb; 915 int err; 916 917 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 918 if (skb == NULL) 919 return ERR_PTR(-ENOBUFS); 920 921 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 922 if (err < 0) { 923 nlmsg_free(skb); 924 return ERR_PTR(err); 925 } 926 927 return skb; 928 } 929 930 static struct sk_buff * 931 ctrl_build_mcgrp_msg(const struct genl_family *family, 932 const struct genl_multicast_group *grp, 933 int grp_id, u32 portid, int seq, u8 cmd) 934 { 935 struct sk_buff *skb; 936 int err; 937 938 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 939 if (skb == NULL) 940 return ERR_PTR(-ENOBUFS); 941 942 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 943 seq, 0, skb, cmd); 944 if (err < 0) { 945 nlmsg_free(skb); 946 return ERR_PTR(err); 947 } 948 949 return skb; 950 } 951 952 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 953 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 954 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 955 .len = GENL_NAMSIZ - 1 }, 956 }; 957 958 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 959 { 960 struct sk_buff *msg; 961 const struct genl_family *res = NULL; 962 int err = -EINVAL; 963 964 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 965 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 966 res = genl_family_find_byid(id); 967 err = -ENOENT; 968 } 969 970 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 971 char *name; 972 973 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 974 res = genl_family_find_byname(name); 975 #ifdef CONFIG_MODULES 976 if (res == NULL) { 977 genl_unlock(); 978 up_read(&cb_lock); 979 request_module("net-pf-%d-proto-%d-family-%s", 980 PF_NETLINK, NETLINK_GENERIC, name); 981 down_read(&cb_lock); 982 genl_lock(); 983 res = genl_family_find_byname(name); 984 } 985 #endif 986 err = -ENOENT; 987 } 988 989 if (res == NULL) 990 return err; 991 992 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 993 /* family doesn't exist here */ 994 return -ENOENT; 995 } 996 997 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 998 CTRL_CMD_NEWFAMILY); 999 if (IS_ERR(msg)) 1000 return PTR_ERR(msg); 1001 1002 return genlmsg_reply(msg, info); 1003 } 1004 1005 static int genl_ctrl_event(int event, const struct genl_family *family, 1006 const struct genl_multicast_group *grp, 1007 int grp_id) 1008 { 1009 struct sk_buff *msg; 1010 1011 /* genl is still initialising */ 1012 if (!init_net.genl_sock) 1013 return 0; 1014 1015 switch (event) { 1016 case CTRL_CMD_NEWFAMILY: 1017 case CTRL_CMD_DELFAMILY: 1018 WARN_ON(grp); 1019 msg = ctrl_build_family_msg(family, 0, 0, event); 1020 break; 1021 case CTRL_CMD_NEWMCAST_GRP: 1022 case CTRL_CMD_DELMCAST_GRP: 1023 BUG_ON(!grp); 1024 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 1025 break; 1026 default: 1027 return -EINVAL; 1028 } 1029 1030 if (IS_ERR(msg)) 1031 return PTR_ERR(msg); 1032 1033 if (!family->netnsok) { 1034 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 1035 0, GFP_KERNEL); 1036 } else { 1037 rcu_read_lock(); 1038 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 1039 0, GFP_ATOMIC); 1040 rcu_read_unlock(); 1041 } 1042 1043 return 0; 1044 } 1045 1046 static const struct genl_ops genl_ctrl_ops[] = { 1047 { 1048 .cmd = CTRL_CMD_GETFAMILY, 1049 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1050 .doit = ctrl_getfamily, 1051 .dumpit = ctrl_dumpfamily, 1052 }, 1053 }; 1054 1055 static const struct genl_multicast_group genl_ctrl_groups[] = { 1056 { .name = "notify", }, 1057 }; 1058 1059 static struct genl_family genl_ctrl __ro_after_init = { 1060 .module = THIS_MODULE, 1061 .ops = genl_ctrl_ops, 1062 .n_ops = ARRAY_SIZE(genl_ctrl_ops), 1063 .mcgrps = genl_ctrl_groups, 1064 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), 1065 .id = GENL_ID_CTRL, 1066 .name = "nlctrl", 1067 .version = 0x2, 1068 .maxattr = CTRL_ATTR_MAX, 1069 .policy = ctrl_policy, 1070 .netnsok = true, 1071 }; 1072 1073 static int genl_bind(struct net *net, int group) 1074 { 1075 struct genl_family *f; 1076 int err = -ENOENT; 1077 unsigned int id; 1078 1079 down_read(&cb_lock); 1080 1081 idr_for_each_entry(&genl_fam_idr, f, id) { 1082 if (group >= f->mcgrp_offset && 1083 group < f->mcgrp_offset + f->n_mcgrps) { 1084 int fam_grp = group - f->mcgrp_offset; 1085 1086 if (!f->netnsok && net != &init_net) 1087 err = -ENOENT; 1088 else if (f->mcast_bind) 1089 err = f->mcast_bind(net, fam_grp); 1090 else 1091 err = 0; 1092 break; 1093 } 1094 } 1095 up_read(&cb_lock); 1096 1097 return err; 1098 } 1099 1100 static void genl_unbind(struct net *net, int group) 1101 { 1102 struct genl_family *f; 1103 unsigned int id; 1104 1105 down_read(&cb_lock); 1106 1107 idr_for_each_entry(&genl_fam_idr, f, id) { 1108 if (group >= f->mcgrp_offset && 1109 group < f->mcgrp_offset + f->n_mcgrps) { 1110 int fam_grp = group - f->mcgrp_offset; 1111 1112 if (f->mcast_unbind) 1113 f->mcast_unbind(net, fam_grp); 1114 break; 1115 } 1116 } 1117 up_read(&cb_lock); 1118 } 1119 1120 static int __net_init genl_pernet_init(struct net *net) 1121 { 1122 struct netlink_kernel_cfg cfg = { 1123 .input = genl_rcv, 1124 .flags = NL_CFG_F_NONROOT_RECV, 1125 .bind = genl_bind, 1126 .unbind = genl_unbind, 1127 }; 1128 1129 /* we'll bump the group number right afterwards */ 1130 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1131 1132 if (!net->genl_sock && net_eq(net, &init_net)) 1133 panic("GENL: Cannot initialize generic netlink\n"); 1134 1135 if (!net->genl_sock) 1136 return -ENOMEM; 1137 1138 return 0; 1139 } 1140 1141 static void __net_exit genl_pernet_exit(struct net *net) 1142 { 1143 netlink_kernel_release(net->genl_sock); 1144 net->genl_sock = NULL; 1145 } 1146 1147 static struct pernet_operations genl_pernet_ops = { 1148 .init = genl_pernet_init, 1149 .exit = genl_pernet_exit, 1150 }; 1151 1152 static int __init genl_init(void) 1153 { 1154 int err; 1155 1156 err = genl_register_family(&genl_ctrl); 1157 if (err < 0) 1158 goto problem; 1159 1160 err = register_pernet_subsys(&genl_pernet_ops); 1161 if (err) 1162 goto problem; 1163 1164 return 0; 1165 1166 problem: 1167 panic("GENL: Cannot register controller: %d\n", err); 1168 } 1169 1170 subsys_initcall(genl_init); 1171 1172 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1173 gfp_t flags) 1174 { 1175 struct sk_buff *tmp; 1176 struct net *net, *prev = NULL; 1177 bool delivered = false; 1178 int err; 1179 1180 for_each_net_rcu(net) { 1181 if (prev) { 1182 tmp = skb_clone(skb, flags); 1183 if (!tmp) { 1184 err = -ENOMEM; 1185 goto error; 1186 } 1187 err = nlmsg_multicast(prev->genl_sock, tmp, 1188 portid, group, flags); 1189 if (!err) 1190 delivered = true; 1191 else if (err != -ESRCH) 1192 goto error; 1193 } 1194 1195 prev = net; 1196 } 1197 1198 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1199 if (!err) 1200 delivered = true; 1201 else if (err != -ESRCH) 1202 return err; 1203 return delivered ? 0 : -ESRCH; 1204 error: 1205 kfree_skb(skb); 1206 return err; 1207 } 1208 1209 int genlmsg_multicast_allns(const struct genl_family *family, 1210 struct sk_buff *skb, u32 portid, 1211 unsigned int group, gfp_t flags) 1212 { 1213 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1214 return -EINVAL; 1215 group = family->mcgrp_offset + group; 1216 return genlmsg_mcast(skb, portid, group, flags); 1217 } 1218 EXPORT_SYMBOL(genlmsg_multicast_allns); 1219 1220 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 1221 struct genl_info *info, u32 group, gfp_t flags) 1222 { 1223 struct net *net = genl_info_net(info); 1224 struct sock *sk = net->genl_sock; 1225 int report = 0; 1226 1227 if (info->nlhdr) 1228 report = nlmsg_report(info->nlhdr); 1229 1230 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1231 return; 1232 group = family->mcgrp_offset + group; 1233 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1234 } 1235 EXPORT_SYMBOL(genl_notify); 1236