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_helpers.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 #include "genetlink.h" 26 27 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ 28 static DECLARE_RWSEM(cb_lock); 29 30 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); 31 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); 32 33 void genl_lock(void) 34 { 35 mutex_lock(&genl_mutex); 36 } 37 EXPORT_SYMBOL(genl_lock); 38 39 void genl_unlock(void) 40 { 41 mutex_unlock(&genl_mutex); 42 } 43 EXPORT_SYMBOL(genl_unlock); 44 45 static void genl_lock_all(void) 46 { 47 down_write(&cb_lock); 48 genl_lock(); 49 } 50 51 static void genl_unlock_all(void) 52 { 53 genl_unlock(); 54 up_write(&cb_lock); 55 } 56 57 static void genl_op_lock(const struct genl_family *family) 58 { 59 if (!family->parallel_ops) 60 genl_lock(); 61 } 62 63 static void genl_op_unlock(const struct genl_family *family) 64 { 65 if (!family->parallel_ops) 66 genl_unlock(); 67 } 68 69 static DEFINE_IDR(genl_fam_idr); 70 71 /* 72 * Bitmap of multicast groups that are currently in use. 73 * 74 * To avoid an allocation at boot of just one unsigned long, 75 * declare it global instead. 76 * Bit 0 is marked as already used since group 0 is invalid. 77 * Bit 1 is marked as already used since the drop-monitor code 78 * abuses the API and thinks it can statically use group 1. 79 * That group will typically conflict with other groups that 80 * any proper users use. 81 * Bit 16 is marked as used since it's used for generic netlink 82 * and the code no longer marks pre-reserved IDs as used. 83 * Bit 17 is marked as already used since the VFS quota code 84 * also abused this API and relied on family == group ID, we 85 * cater to that by giving it a static family and group ID. 86 * Bit 18 is marked as already used since the PMCRAID driver 87 * did the same thing as the VFS quota code (maybe copied?) 88 */ 89 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | 90 BIT(GENL_ID_VFS_DQUOT) | 91 BIT(GENL_ID_PMCRAID); 92 static unsigned long *mc_groups = &mc_group_start; 93 static unsigned long mc_groups_longs = 1; 94 95 /* We need the last attribute with non-zero ID therefore a 2-entry array */ 96 static struct nla_policy genl_policy_reject_all[] = { 97 { .type = NLA_REJECT }, 98 { .type = NLA_REJECT }, 99 }; 100 101 static int genl_ctrl_event(int event, const struct genl_family *family, 102 const struct genl_multicast_group *grp, 103 int grp_id); 104 105 static void 106 genl_op_fill_in_reject_policy(const struct genl_family *family, 107 struct genl_ops *op) 108 { 109 BUILD_BUG_ON(ARRAY_SIZE(genl_policy_reject_all) - 1 != 1); 110 111 if (op->policy || op->cmd < family->resv_start_op) 112 return; 113 114 op->policy = genl_policy_reject_all; 115 op->maxattr = 1; 116 } 117 118 static void 119 genl_op_fill_in_reject_policy_split(const struct genl_family *family, 120 struct genl_split_ops *op) 121 { 122 if (op->policy) 123 return; 124 125 op->policy = genl_policy_reject_all; 126 op->maxattr = 1; 127 } 128 129 static const struct genl_family *genl_family_find_byid(unsigned int id) 130 { 131 return idr_find(&genl_fam_idr, id); 132 } 133 134 static const struct genl_family *genl_family_find_byname(char *name) 135 { 136 const struct genl_family *family; 137 unsigned int id; 138 139 idr_for_each_entry(&genl_fam_idr, family, id) 140 if (strcmp(family->name, name) == 0) 141 return family; 142 143 return NULL; 144 } 145 146 struct genl_op_iter { 147 const struct genl_family *family; 148 struct genl_split_ops doit; 149 struct genl_split_ops dumpit; 150 int cmd_idx; 151 int entry_idx; 152 u32 cmd; 153 u8 flags; 154 }; 155 156 static void genl_op_from_full(const struct genl_family *family, 157 unsigned int i, struct genl_ops *op) 158 { 159 *op = family->ops[i]; 160 161 if (!op->maxattr) 162 op->maxattr = family->maxattr; 163 if (!op->policy) 164 op->policy = family->policy; 165 166 genl_op_fill_in_reject_policy(family, op); 167 } 168 169 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family, 170 struct genl_ops *op) 171 { 172 int i; 173 174 for (i = 0; i < family->n_ops; i++) 175 if (family->ops[i].cmd == cmd) { 176 genl_op_from_full(family, i, op); 177 return 0; 178 } 179 180 return -ENOENT; 181 } 182 183 static void genl_op_from_small(const struct genl_family *family, 184 unsigned int i, struct genl_ops *op) 185 { 186 memset(op, 0, sizeof(*op)); 187 op->doit = family->small_ops[i].doit; 188 op->dumpit = family->small_ops[i].dumpit; 189 op->cmd = family->small_ops[i].cmd; 190 op->internal_flags = family->small_ops[i].internal_flags; 191 op->flags = family->small_ops[i].flags; 192 op->validate = family->small_ops[i].validate; 193 194 op->maxattr = family->maxattr; 195 op->policy = family->policy; 196 197 genl_op_fill_in_reject_policy(family, op); 198 } 199 200 static int genl_get_cmd_small(u32 cmd, const struct genl_family *family, 201 struct genl_ops *op) 202 { 203 int i; 204 205 for (i = 0; i < family->n_small_ops; i++) 206 if (family->small_ops[i].cmd == cmd) { 207 genl_op_from_small(family, i, op); 208 return 0; 209 } 210 211 return -ENOENT; 212 } 213 214 static void genl_op_from_split(struct genl_op_iter *iter) 215 { 216 const struct genl_family *family = iter->family; 217 int i, cnt = 0; 218 219 i = iter->entry_idx - family->n_ops - family->n_small_ops; 220 221 if (family->split_ops[i + cnt].flags & GENL_CMD_CAP_DO) { 222 iter->doit = family->split_ops[i + cnt]; 223 genl_op_fill_in_reject_policy_split(family, &iter->doit); 224 cnt++; 225 } else { 226 memset(&iter->doit, 0, sizeof(iter->doit)); 227 } 228 229 if (i + cnt < family->n_split_ops && 230 family->split_ops[i + cnt].flags & GENL_CMD_CAP_DUMP && 231 (!cnt || family->split_ops[i + cnt].cmd == iter->doit.cmd)) { 232 iter->dumpit = family->split_ops[i + cnt]; 233 genl_op_fill_in_reject_policy_split(family, &iter->dumpit); 234 cnt++; 235 } else { 236 memset(&iter->dumpit, 0, sizeof(iter->dumpit)); 237 } 238 239 WARN_ON(!cnt); 240 iter->entry_idx += cnt; 241 } 242 243 static int 244 genl_get_cmd_split(u32 cmd, u8 flag, const struct genl_family *family, 245 struct genl_split_ops *op) 246 { 247 int i; 248 249 for (i = 0; i < family->n_split_ops; i++) 250 if (family->split_ops[i].cmd == cmd && 251 family->split_ops[i].flags & flag) { 252 *op = family->split_ops[i]; 253 return 0; 254 } 255 256 return -ENOENT; 257 } 258 259 static int 260 genl_cmd_full_to_split(struct genl_split_ops *op, 261 const struct genl_family *family, 262 const struct genl_ops *full, u8 flags) 263 { 264 if ((flags & GENL_CMD_CAP_DO && !full->doit) || 265 (flags & GENL_CMD_CAP_DUMP && !full->dumpit)) { 266 memset(op, 0, sizeof(*op)); 267 return -ENOENT; 268 } 269 270 if (flags & GENL_CMD_CAP_DUMP) { 271 op->start = full->start; 272 op->dumpit = full->dumpit; 273 op->done = full->done; 274 } else { 275 op->pre_doit = family->pre_doit; 276 op->doit = full->doit; 277 op->post_doit = family->post_doit; 278 } 279 280 if (flags & GENL_CMD_CAP_DUMP && 281 full->validate & GENL_DONT_VALIDATE_DUMP) { 282 op->policy = NULL; 283 op->maxattr = 0; 284 } else { 285 op->policy = full->policy; 286 op->maxattr = full->maxattr; 287 } 288 289 op->cmd = full->cmd; 290 op->internal_flags = full->internal_flags; 291 op->flags = full->flags; 292 op->validate = full->validate; 293 294 /* Make sure flags include the GENL_CMD_CAP_DO / GENL_CMD_CAP_DUMP */ 295 op->flags |= flags; 296 297 return 0; 298 } 299 300 /* Must make sure that op is initialized to 0 on failure */ 301 static int 302 genl_get_cmd(u32 cmd, u8 flags, const struct genl_family *family, 303 struct genl_split_ops *op) 304 { 305 struct genl_ops full; 306 int err; 307 308 err = genl_get_cmd_full(cmd, family, &full); 309 if (err == -ENOENT) 310 err = genl_get_cmd_small(cmd, family, &full); 311 /* Found one of legacy forms */ 312 if (err == 0) 313 return genl_cmd_full_to_split(op, family, &full, flags); 314 315 err = genl_get_cmd_split(cmd, flags, family, op); 316 if (err) 317 memset(op, 0, sizeof(*op)); 318 return err; 319 } 320 321 /* For policy dumping only, get ops of both do and dump. 322 * Fail if both are missing, genl_get_cmd() will zero-init in case of failure. 323 */ 324 static int 325 genl_get_cmd_both(u32 cmd, const struct genl_family *family, 326 struct genl_split_ops *doit, struct genl_split_ops *dumpit) 327 { 328 int err1, err2; 329 330 err1 = genl_get_cmd(cmd, GENL_CMD_CAP_DO, family, doit); 331 err2 = genl_get_cmd(cmd, GENL_CMD_CAP_DUMP, family, dumpit); 332 333 return err1 && err2 ? -ENOENT : 0; 334 } 335 336 static bool 337 genl_op_iter_init(const struct genl_family *family, struct genl_op_iter *iter) 338 { 339 iter->family = family; 340 iter->cmd_idx = 0; 341 iter->entry_idx = 0; 342 343 iter->flags = 0; 344 345 return iter->family->n_ops + 346 iter->family->n_small_ops + 347 iter->family->n_split_ops; 348 } 349 350 static bool genl_op_iter_next(struct genl_op_iter *iter) 351 { 352 const struct genl_family *family = iter->family; 353 bool legacy_op = true; 354 struct genl_ops op; 355 356 if (iter->entry_idx < family->n_ops) { 357 genl_op_from_full(family, iter->entry_idx, &op); 358 } else if (iter->entry_idx < family->n_ops + family->n_small_ops) { 359 genl_op_from_small(family, iter->entry_idx - family->n_ops, 360 &op); 361 } else if (iter->entry_idx < 362 family->n_ops + family->n_small_ops + family->n_split_ops) { 363 legacy_op = false; 364 /* updates entry_idx */ 365 genl_op_from_split(iter); 366 } else { 367 return false; 368 } 369 370 iter->cmd_idx++; 371 372 if (legacy_op) { 373 iter->entry_idx++; 374 375 genl_cmd_full_to_split(&iter->doit, family, 376 &op, GENL_CMD_CAP_DO); 377 genl_cmd_full_to_split(&iter->dumpit, family, 378 &op, GENL_CMD_CAP_DUMP); 379 } 380 381 iter->cmd = iter->doit.cmd | iter->dumpit.cmd; 382 iter->flags = iter->doit.flags | iter->dumpit.flags; 383 384 return true; 385 } 386 387 static void 388 genl_op_iter_copy(struct genl_op_iter *dst, struct genl_op_iter *src) 389 { 390 *dst = *src; 391 } 392 393 static unsigned int genl_op_iter_idx(struct genl_op_iter *iter) 394 { 395 return iter->cmd_idx; 396 } 397 398 static int genl_allocate_reserve_groups(int n_groups, int *first_id) 399 { 400 unsigned long *new_groups; 401 int start = 0; 402 int i; 403 int id; 404 bool fits; 405 406 do { 407 if (start == 0) 408 id = find_first_zero_bit(mc_groups, 409 mc_groups_longs * 410 BITS_PER_LONG); 411 else 412 id = find_next_zero_bit(mc_groups, 413 mc_groups_longs * BITS_PER_LONG, 414 start); 415 416 fits = true; 417 for (i = id; 418 i < min_t(int, id + n_groups, 419 mc_groups_longs * BITS_PER_LONG); 420 i++) { 421 if (test_bit(i, mc_groups)) { 422 start = i; 423 fits = false; 424 break; 425 } 426 } 427 428 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { 429 unsigned long new_longs = mc_groups_longs + 430 BITS_TO_LONGS(n_groups); 431 size_t nlen = new_longs * sizeof(unsigned long); 432 433 if (mc_groups == &mc_group_start) { 434 new_groups = kzalloc(nlen, GFP_KERNEL); 435 if (!new_groups) 436 return -ENOMEM; 437 mc_groups = new_groups; 438 *mc_groups = mc_group_start; 439 } else { 440 new_groups = krealloc(mc_groups, nlen, 441 GFP_KERNEL); 442 if (!new_groups) 443 return -ENOMEM; 444 mc_groups = new_groups; 445 for (i = 0; i < BITS_TO_LONGS(n_groups); i++) 446 mc_groups[mc_groups_longs + i] = 0; 447 } 448 mc_groups_longs = new_longs; 449 } 450 } while (!fits); 451 452 for (i = id; i < id + n_groups; i++) 453 set_bit(i, mc_groups); 454 *first_id = id; 455 return 0; 456 } 457 458 static struct genl_family genl_ctrl; 459 460 static int genl_validate_assign_mc_groups(struct genl_family *family) 461 { 462 int first_id; 463 int n_groups = family->n_mcgrps; 464 int err = 0, i; 465 bool groups_allocated = false; 466 467 if (!n_groups) 468 return 0; 469 470 for (i = 0; i < n_groups; i++) { 471 const struct genl_multicast_group *grp = &family->mcgrps[i]; 472 473 if (WARN_ON(grp->name[0] == '\0')) 474 return -EINVAL; 475 if (WARN_ON(!string_is_terminated(grp->name, GENL_NAMSIZ))) 476 return -EINVAL; 477 } 478 479 /* special-case our own group and hacks */ 480 if (family == &genl_ctrl) { 481 first_id = GENL_ID_CTRL; 482 BUG_ON(n_groups != 1); 483 } else if (strcmp(family->name, "NET_DM") == 0) { 484 first_id = 1; 485 BUG_ON(n_groups != 1); 486 } else if (family->id == GENL_ID_VFS_DQUOT) { 487 first_id = GENL_ID_VFS_DQUOT; 488 BUG_ON(n_groups != 1); 489 } else if (family->id == GENL_ID_PMCRAID) { 490 first_id = GENL_ID_PMCRAID; 491 BUG_ON(n_groups != 1); 492 } else { 493 groups_allocated = true; 494 err = genl_allocate_reserve_groups(n_groups, &first_id); 495 if (err) 496 return err; 497 } 498 499 family->mcgrp_offset = first_id; 500 501 /* if still initializing, can't and don't need to realloc bitmaps */ 502 if (!init_net.genl_sock) 503 return 0; 504 505 if (family->netnsok) { 506 struct net *net; 507 508 netlink_table_grab(); 509 rcu_read_lock(); 510 for_each_net_rcu(net) { 511 err = __netlink_change_ngroups(net->genl_sock, 512 mc_groups_longs * BITS_PER_LONG); 513 if (err) { 514 /* 515 * No need to roll back, can only fail if 516 * memory allocation fails and then the 517 * number of _possible_ groups has been 518 * increased on some sockets which is ok. 519 */ 520 break; 521 } 522 } 523 rcu_read_unlock(); 524 netlink_table_ungrab(); 525 } else { 526 err = netlink_change_ngroups(init_net.genl_sock, 527 mc_groups_longs * BITS_PER_LONG); 528 } 529 530 if (groups_allocated && err) { 531 for (i = 0; i < family->n_mcgrps; i++) 532 clear_bit(family->mcgrp_offset + i, mc_groups); 533 } 534 535 return err; 536 } 537 538 static void genl_unregister_mc_groups(const struct genl_family *family) 539 { 540 struct net *net; 541 int i; 542 543 netlink_table_grab(); 544 rcu_read_lock(); 545 for_each_net_rcu(net) { 546 for (i = 0; i < family->n_mcgrps; i++) 547 __netlink_clear_multicast_users( 548 net->genl_sock, family->mcgrp_offset + i); 549 } 550 rcu_read_unlock(); 551 netlink_table_ungrab(); 552 553 for (i = 0; i < family->n_mcgrps; i++) { 554 int grp_id = family->mcgrp_offset + i; 555 556 if (grp_id != 1) 557 clear_bit(grp_id, mc_groups); 558 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, 559 &family->mcgrps[i], grp_id); 560 } 561 } 562 563 static bool genl_split_op_check(const struct genl_split_ops *op) 564 { 565 if (WARN_ON(hweight8(op->flags & (GENL_CMD_CAP_DO | 566 GENL_CMD_CAP_DUMP)) != 1)) 567 return true; 568 return false; 569 } 570 571 static int genl_validate_ops(const struct genl_family *family) 572 { 573 struct genl_op_iter i, j; 574 unsigned int s; 575 576 if (WARN_ON(family->n_ops && !family->ops) || 577 WARN_ON(family->n_small_ops && !family->small_ops) || 578 WARN_ON(family->n_split_ops && !family->split_ops)) 579 return -EINVAL; 580 581 for (genl_op_iter_init(family, &i); genl_op_iter_next(&i); ) { 582 if (!(i.flags & (GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP))) 583 return -EINVAL; 584 585 if (WARN_ON(i.cmd >= family->resv_start_op && 586 (i.doit.validate || i.dumpit.validate))) 587 return -EINVAL; 588 589 genl_op_iter_copy(&j, &i); 590 while (genl_op_iter_next(&j)) { 591 if (i.cmd == j.cmd) 592 return -EINVAL; 593 } 594 } 595 596 if (family->n_split_ops) { 597 if (genl_split_op_check(&family->split_ops[0])) 598 return -EINVAL; 599 } 600 601 for (s = 1; s < family->n_split_ops; s++) { 602 const struct genl_split_ops *a, *b; 603 604 a = &family->split_ops[s - 1]; 605 b = &family->split_ops[s]; 606 607 if (genl_split_op_check(b)) 608 return -EINVAL; 609 610 /* Check sort order */ 611 if (a->cmd < b->cmd) { 612 continue; 613 } else if (a->cmd > b->cmd) { 614 WARN_ON(1); 615 return -EINVAL; 616 } 617 618 if (a->internal_flags != b->internal_flags || 619 ((a->flags ^ b->flags) & ~(GENL_CMD_CAP_DO | 620 GENL_CMD_CAP_DUMP))) { 621 WARN_ON(1); 622 return -EINVAL; 623 } 624 625 if ((a->flags & GENL_CMD_CAP_DO) && 626 (b->flags & GENL_CMD_CAP_DUMP)) 627 continue; 628 629 WARN_ON(1); 630 return -EINVAL; 631 } 632 633 return 0; 634 } 635 636 static void *genl_sk_priv_alloc(struct genl_family *family) 637 { 638 void *priv; 639 640 priv = kzalloc(family->sock_priv_size, GFP_KERNEL); 641 if (!priv) 642 return ERR_PTR(-ENOMEM); 643 644 if (family->sock_priv_init) 645 family->sock_priv_init(priv); 646 647 return priv; 648 } 649 650 static void genl_sk_priv_free(const struct genl_family *family, void *priv) 651 { 652 if (family->sock_priv_destroy) 653 family->sock_priv_destroy(priv); 654 kfree(priv); 655 } 656 657 static int genl_sk_privs_alloc(struct genl_family *family) 658 { 659 if (!family->sock_priv_size) 660 return 0; 661 662 family->sock_privs = kzalloc(sizeof(*family->sock_privs), GFP_KERNEL); 663 if (!family->sock_privs) 664 return -ENOMEM; 665 xa_init(family->sock_privs); 666 return 0; 667 } 668 669 static void genl_sk_privs_free(const struct genl_family *family) 670 { 671 unsigned long id; 672 void *priv; 673 674 if (!family->sock_priv_size) 675 return; 676 677 xa_for_each(family->sock_privs, id, priv) 678 genl_sk_priv_free(family, priv); 679 680 xa_destroy(family->sock_privs); 681 kfree(family->sock_privs); 682 } 683 684 static void genl_sk_priv_free_by_sock(struct genl_family *family, 685 struct sock *sk) 686 { 687 void *priv; 688 689 if (!family->sock_priv_size) 690 return; 691 priv = xa_erase(family->sock_privs, (unsigned long) sk); 692 if (!priv) 693 return; 694 genl_sk_priv_free(family, priv); 695 } 696 697 static void genl_release(struct sock *sk, unsigned long *groups) 698 { 699 struct genl_family *family; 700 unsigned int id; 701 702 down_read(&cb_lock); 703 704 idr_for_each_entry(&genl_fam_idr, family, id) 705 genl_sk_priv_free_by_sock(family, sk); 706 707 up_read(&cb_lock); 708 } 709 710 /** 711 * __genl_sk_priv_get - Get family private pointer for socket, if exists 712 * 713 * @family: family 714 * @sk: socket 715 * 716 * Lookup a private memory for a Generic netlink family and specified socket. 717 * 718 * Caller should make sure this is called in RCU read locked section. 719 * 720 * Return: valid pointer on success, otherwise negative error value 721 * encoded by ERR_PTR(), NULL in case priv does not exist. 722 */ 723 void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk) 724 { 725 if (WARN_ON_ONCE(!family->sock_privs)) 726 return ERR_PTR(-EINVAL); 727 return xa_load(family->sock_privs, (unsigned long) sk); 728 } 729 730 /** 731 * genl_sk_priv_get - Get family private pointer for socket 732 * 733 * @family: family 734 * @sk: socket 735 * 736 * Lookup a private memory for a Generic netlink family and specified socket. 737 * Allocate the private memory in case it was not already done. 738 * 739 * Return: valid pointer on success, otherwise negative error value 740 * encoded by ERR_PTR(). 741 */ 742 void *genl_sk_priv_get(struct genl_family *family, struct sock *sk) 743 { 744 void *priv, *old_priv; 745 746 priv = __genl_sk_priv_get(family, sk); 747 if (priv) 748 return priv; 749 750 /* priv for the family does not exist so far, create it. */ 751 752 priv = genl_sk_priv_alloc(family); 753 if (IS_ERR(priv)) 754 return ERR_CAST(priv); 755 756 old_priv = xa_cmpxchg(family->sock_privs, (unsigned long) sk, NULL, 757 priv, GFP_KERNEL); 758 if (old_priv) { 759 genl_sk_priv_free(family, priv); 760 if (xa_is_err(old_priv)) 761 return ERR_PTR(xa_err(old_priv)); 762 /* Race happened, priv for the socket was already inserted. */ 763 return old_priv; 764 } 765 return priv; 766 } 767 768 /** 769 * genl_register_family - register a generic netlink family 770 * @family: generic netlink family 771 * 772 * Registers the specified family after validating it first. Only one 773 * family may be registered with the same family name or identifier. 774 * 775 * The family's ops, multicast groups and module pointer must already 776 * be assigned. 777 * 778 * Return 0 on success or a negative error code. 779 */ 780 int genl_register_family(struct genl_family *family) 781 { 782 int err, i; 783 int start = GENL_START_ALLOC, end = GENL_MAX_ID; 784 785 err = genl_validate_ops(family); 786 if (err) 787 return err; 788 789 genl_lock_all(); 790 791 if (genl_family_find_byname(family->name)) { 792 err = -EEXIST; 793 goto errout_locked; 794 } 795 796 err = genl_sk_privs_alloc(family); 797 if (err) 798 goto errout_locked; 799 800 /* 801 * Sadly, a few cases need to be special-cased 802 * due to them having previously abused the API 803 * and having used their family ID also as their 804 * multicast group ID, so we use reserved IDs 805 * for both to be sure we can do that mapping. 806 */ 807 if (family == &genl_ctrl) { 808 /* and this needs to be special for initial family lookups */ 809 start = end = GENL_ID_CTRL; 810 } else if (strcmp(family->name, "pmcraid") == 0) { 811 start = end = GENL_ID_PMCRAID; 812 } else if (strcmp(family->name, "VFS_DQUOT") == 0) { 813 start = end = GENL_ID_VFS_DQUOT; 814 } 815 816 family->id = idr_alloc_cyclic(&genl_fam_idr, family, 817 start, end + 1, GFP_KERNEL); 818 if (family->id < 0) { 819 err = family->id; 820 goto errout_sk_privs_free; 821 } 822 823 err = genl_validate_assign_mc_groups(family); 824 if (err) 825 goto errout_remove; 826 827 genl_unlock_all(); 828 829 /* send all events */ 830 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); 831 for (i = 0; i < family->n_mcgrps; i++) 832 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, 833 &family->mcgrps[i], family->mcgrp_offset + i); 834 835 return 0; 836 837 errout_remove: 838 idr_remove(&genl_fam_idr, family->id); 839 errout_sk_privs_free: 840 genl_sk_privs_free(family); 841 errout_locked: 842 genl_unlock_all(); 843 return err; 844 } 845 EXPORT_SYMBOL(genl_register_family); 846 847 /** 848 * genl_unregister_family - unregister generic netlink family 849 * @family: generic netlink family 850 * 851 * Unregisters the specified family. 852 * 853 * Returns 0 on success or a negative error code. 854 */ 855 int genl_unregister_family(const struct genl_family *family) 856 { 857 genl_lock_all(); 858 859 if (!genl_family_find_byid(family->id)) { 860 genl_unlock_all(); 861 return -ENOENT; 862 } 863 864 genl_unregister_mc_groups(family); 865 866 idr_remove(&genl_fam_idr, family->id); 867 868 up_write(&cb_lock); 869 wait_event(genl_sk_destructing_waitq, 870 atomic_read(&genl_sk_destructing_cnt) == 0); 871 872 genl_sk_privs_free(family); 873 874 genl_unlock(); 875 876 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); 877 878 return 0; 879 } 880 EXPORT_SYMBOL(genl_unregister_family); 881 882 /** 883 * genlmsg_put - Add generic netlink header to netlink message 884 * @skb: socket buffer holding the message 885 * @portid: netlink portid the message is addressed to 886 * @seq: sequence number (usually the one of the sender) 887 * @family: generic netlink family 888 * @flags: netlink message flags 889 * @cmd: generic netlink command 890 * 891 * Returns pointer to user specific header 892 */ 893 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, 894 const struct genl_family *family, int flags, u8 cmd) 895 { 896 struct nlmsghdr *nlh; 897 struct genlmsghdr *hdr; 898 899 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + 900 family->hdrsize, flags); 901 if (nlh == NULL) 902 return NULL; 903 904 hdr = nlmsg_data(nlh); 905 hdr->cmd = cmd; 906 hdr->version = family->version; 907 hdr->reserved = 0; 908 909 return (char *) hdr + GENL_HDRLEN; 910 } 911 EXPORT_SYMBOL(genlmsg_put); 912 913 static struct genl_dumpit_info *genl_dumpit_info_alloc(void) 914 { 915 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL); 916 } 917 918 static void genl_dumpit_info_free(const struct genl_dumpit_info *info) 919 { 920 kfree(info); 921 } 922 923 static struct nlattr ** 924 genl_family_rcv_msg_attrs_parse(const struct genl_family *family, 925 struct nlmsghdr *nlh, 926 struct netlink_ext_ack *extack, 927 const struct genl_split_ops *ops, 928 int hdrlen, 929 enum genl_validate_flags no_strict_flag) 930 { 931 enum netlink_validation validate = ops->validate & no_strict_flag ? 932 NL_VALIDATE_LIBERAL : 933 NL_VALIDATE_STRICT; 934 struct nlattr **attrbuf; 935 int err; 936 937 if (!ops->maxattr) 938 return NULL; 939 940 attrbuf = kmalloc_array(ops->maxattr + 1, 941 sizeof(struct nlattr *), GFP_KERNEL); 942 if (!attrbuf) 943 return ERR_PTR(-ENOMEM); 944 945 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy, 946 validate, extack); 947 if (err) { 948 kfree(attrbuf); 949 return ERR_PTR(err); 950 } 951 return attrbuf; 952 } 953 954 static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf) 955 { 956 kfree(attrbuf); 957 } 958 959 struct genl_start_context { 960 const struct genl_family *family; 961 struct nlmsghdr *nlh; 962 struct netlink_ext_ack *extack; 963 const struct genl_split_ops *ops; 964 int hdrlen; 965 }; 966 967 static int genl_start(struct netlink_callback *cb) 968 { 969 struct genl_start_context *ctx = cb->data; 970 const struct genl_split_ops *ops; 971 struct genl_dumpit_info *info; 972 struct nlattr **attrs = NULL; 973 int rc = 0; 974 975 ops = ctx->ops; 976 if (!(ops->validate & GENL_DONT_VALIDATE_DUMP) && 977 ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen)) 978 return -EINVAL; 979 980 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack, 981 ops, ctx->hdrlen, 982 GENL_DONT_VALIDATE_DUMP_STRICT); 983 if (IS_ERR(attrs)) 984 return PTR_ERR(attrs); 985 986 info = genl_dumpit_info_alloc(); 987 if (!info) { 988 genl_family_rcv_msg_attrs_free(attrs); 989 return -ENOMEM; 990 } 991 info->op = *ops; 992 info->info.family = ctx->family; 993 info->info.snd_seq = cb->nlh->nlmsg_seq; 994 info->info.snd_portid = NETLINK_CB(cb->skb).portid; 995 info->info.nlhdr = cb->nlh; 996 info->info.genlhdr = nlmsg_data(cb->nlh); 997 info->info.attrs = attrs; 998 genl_info_net_set(&info->info, sock_net(cb->skb->sk)); 999 info->info.extack = cb->extack; 1000 memset(&info->info.user_ptr, 0, sizeof(info->info.user_ptr)); 1001 1002 cb->data = info; 1003 if (ops->start) { 1004 genl_op_lock(ctx->family); 1005 rc = ops->start(cb); 1006 genl_op_unlock(ctx->family); 1007 } 1008 1009 if (rc) { 1010 genl_family_rcv_msg_attrs_free(info->info.attrs); 1011 genl_dumpit_info_free(info); 1012 cb->data = NULL; 1013 } 1014 return rc; 1015 } 1016 1017 static int genl_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 1018 { 1019 struct genl_dumpit_info *dump_info = cb->data; 1020 const struct genl_split_ops *ops = &dump_info->op; 1021 struct genl_info *info = &dump_info->info; 1022 int rc; 1023 1024 info->extack = cb->extack; 1025 1026 genl_op_lock(info->family); 1027 rc = ops->dumpit(skb, cb); 1028 genl_op_unlock(info->family); 1029 return rc; 1030 } 1031 1032 static int genl_done(struct netlink_callback *cb) 1033 { 1034 struct genl_dumpit_info *dump_info = cb->data; 1035 const struct genl_split_ops *ops = &dump_info->op; 1036 struct genl_info *info = &dump_info->info; 1037 int rc = 0; 1038 1039 info->extack = cb->extack; 1040 1041 if (ops->done) { 1042 genl_op_lock(info->family); 1043 rc = ops->done(cb); 1044 genl_op_unlock(info->family); 1045 } 1046 genl_family_rcv_msg_attrs_free(info->attrs); 1047 genl_dumpit_info_free(dump_info); 1048 return rc; 1049 } 1050 1051 static int genl_family_rcv_msg_dumpit(const struct genl_family *family, 1052 struct sk_buff *skb, 1053 struct nlmsghdr *nlh, 1054 struct netlink_ext_ack *extack, 1055 const struct genl_split_ops *ops, 1056 int hdrlen, struct net *net) 1057 { 1058 struct genl_start_context ctx; 1059 struct netlink_dump_control c = { 1060 .module = family->module, 1061 .data = &ctx, 1062 .start = genl_start, 1063 .dump = genl_dumpit, 1064 .done = genl_done, 1065 .extack = extack, 1066 }; 1067 int err; 1068 1069 ctx.family = family; 1070 ctx.nlh = nlh; 1071 ctx.extack = extack; 1072 ctx.ops = ops; 1073 ctx.hdrlen = hdrlen; 1074 1075 genl_op_unlock(family); 1076 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 1077 genl_op_lock(family); 1078 1079 return err; 1080 } 1081 1082 static int genl_family_rcv_msg_doit(const struct genl_family *family, 1083 struct sk_buff *skb, 1084 struct nlmsghdr *nlh, 1085 struct netlink_ext_ack *extack, 1086 const struct genl_split_ops *ops, 1087 int hdrlen, struct net *net) 1088 { 1089 struct nlattr **attrbuf; 1090 struct genl_info info; 1091 int err; 1092 1093 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 1094 ops, hdrlen, 1095 GENL_DONT_VALIDATE_STRICT); 1096 if (IS_ERR(attrbuf)) 1097 return PTR_ERR(attrbuf); 1098 1099 info.snd_seq = nlh->nlmsg_seq; 1100 info.snd_portid = NETLINK_CB(skb).portid; 1101 info.family = family; 1102 info.nlhdr = nlh; 1103 info.genlhdr = nlmsg_data(nlh); 1104 info.attrs = attrbuf; 1105 info.extack = extack; 1106 genl_info_net_set(&info, net); 1107 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 1108 1109 if (ops->pre_doit) { 1110 err = ops->pre_doit(ops, skb, &info); 1111 if (err) 1112 goto out; 1113 } 1114 1115 err = ops->doit(skb, &info); 1116 1117 if (ops->post_doit) 1118 ops->post_doit(ops, skb, &info); 1119 1120 out: 1121 genl_family_rcv_msg_attrs_free(attrbuf); 1122 1123 return err; 1124 } 1125 1126 static int genl_header_check(const struct genl_family *family, 1127 struct nlmsghdr *nlh, struct genlmsghdr *hdr, 1128 struct netlink_ext_ack *extack) 1129 { 1130 u16 flags; 1131 1132 /* Only for commands added after we started validating */ 1133 if (hdr->cmd < family->resv_start_op) 1134 return 0; 1135 1136 if (hdr->reserved) { 1137 NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0"); 1138 return -EINVAL; 1139 } 1140 1141 /* Old netlink flags have pretty loose semantics, allow only the flags 1142 * consumed by the core where we can enforce the meaning. 1143 */ 1144 flags = nlh->nlmsg_flags; 1145 if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */ 1146 flags &= ~NLM_F_DUMP; 1147 if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) { 1148 NL_SET_ERR_MSG(extack, 1149 "ambiguous or reserved bits set in nlmsg_flags"); 1150 return -EINVAL; 1151 } 1152 1153 return 0; 1154 } 1155 1156 static int genl_family_rcv_msg(const struct genl_family *family, 1157 struct sk_buff *skb, 1158 struct nlmsghdr *nlh, 1159 struct netlink_ext_ack *extack) 1160 { 1161 struct net *net = sock_net(skb->sk); 1162 struct genlmsghdr *hdr = nlmsg_data(nlh); 1163 struct genl_split_ops op; 1164 int hdrlen; 1165 u8 flags; 1166 1167 /* this family doesn't exist in this netns */ 1168 if (!family->netnsok && !net_eq(net, &init_net)) 1169 return -ENOENT; 1170 1171 hdrlen = GENL_HDRLEN + family->hdrsize; 1172 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 1173 return -EINVAL; 1174 1175 if (genl_header_check(family, nlh, hdr, extack)) 1176 return -EINVAL; 1177 1178 flags = (nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP ? 1179 GENL_CMD_CAP_DUMP : GENL_CMD_CAP_DO; 1180 if (genl_get_cmd(hdr->cmd, flags, family, &op)) 1181 return -EOPNOTSUPP; 1182 1183 if ((op.flags & GENL_ADMIN_PERM) && 1184 !netlink_capable(skb, CAP_NET_ADMIN)) 1185 return -EPERM; 1186 1187 if ((op.flags & GENL_UNS_ADMIN_PERM) && 1188 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 1189 return -EPERM; 1190 1191 if (flags & GENL_CMD_CAP_DUMP) 1192 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, 1193 &op, hdrlen, net); 1194 else 1195 return genl_family_rcv_msg_doit(family, skb, nlh, extack, 1196 &op, hdrlen, net); 1197 } 1198 1199 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 1200 struct netlink_ext_ack *extack) 1201 { 1202 const struct genl_family *family; 1203 int err; 1204 1205 family = genl_family_find_byid(nlh->nlmsg_type); 1206 if (family == NULL) 1207 return -ENOENT; 1208 1209 genl_op_lock(family); 1210 err = genl_family_rcv_msg(family, skb, nlh, extack); 1211 genl_op_unlock(family); 1212 1213 return err; 1214 } 1215 1216 static void genl_rcv(struct sk_buff *skb) 1217 { 1218 down_read(&cb_lock); 1219 netlink_rcv_skb(skb, &genl_rcv_msg); 1220 up_read(&cb_lock); 1221 } 1222 1223 /************************************************************************** 1224 * Controller 1225 **************************************************************************/ 1226 1227 static struct genl_family genl_ctrl; 1228 1229 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 1230 u32 flags, struct sk_buff *skb, u8 cmd) 1231 { 1232 struct genl_op_iter i; 1233 void *hdr; 1234 1235 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 1236 if (hdr == NULL) 1237 return -EMSGSIZE; 1238 1239 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 1240 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 1241 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 1242 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 1243 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 1244 goto nla_put_failure; 1245 1246 if (genl_op_iter_init(family, &i)) { 1247 struct nlattr *nla_ops; 1248 1249 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS); 1250 if (nla_ops == NULL) 1251 goto nla_put_failure; 1252 1253 while (genl_op_iter_next(&i)) { 1254 struct nlattr *nest; 1255 u32 op_flags; 1256 1257 op_flags = i.flags; 1258 if (i.doit.policy || i.dumpit.policy) 1259 op_flags |= GENL_CMD_CAP_HASPOL; 1260 1261 nest = nla_nest_start_noflag(skb, genl_op_iter_idx(&i)); 1262 if (nest == NULL) 1263 goto nla_put_failure; 1264 1265 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, i.cmd) || 1266 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 1267 goto nla_put_failure; 1268 1269 nla_nest_end(skb, nest); 1270 } 1271 1272 nla_nest_end(skb, nla_ops); 1273 } 1274 1275 if (family->n_mcgrps) { 1276 struct nlattr *nla_grps; 1277 int i; 1278 1279 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 1280 if (nla_grps == NULL) 1281 goto nla_put_failure; 1282 1283 for (i = 0; i < family->n_mcgrps; i++) { 1284 struct nlattr *nest; 1285 const struct genl_multicast_group *grp; 1286 1287 grp = &family->mcgrps[i]; 1288 1289 nest = nla_nest_start_noflag(skb, i + 1); 1290 if (nest == NULL) 1291 goto nla_put_failure; 1292 1293 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 1294 family->mcgrp_offset + i) || 1295 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 1296 grp->name)) 1297 goto nla_put_failure; 1298 1299 nla_nest_end(skb, nest); 1300 } 1301 nla_nest_end(skb, nla_grps); 1302 } 1303 1304 genlmsg_end(skb, hdr); 1305 return 0; 1306 1307 nla_put_failure: 1308 genlmsg_cancel(skb, hdr); 1309 return -EMSGSIZE; 1310 } 1311 1312 static int ctrl_fill_mcgrp_info(const struct genl_family *family, 1313 const struct genl_multicast_group *grp, 1314 int grp_id, u32 portid, u32 seq, u32 flags, 1315 struct sk_buff *skb, u8 cmd) 1316 { 1317 void *hdr; 1318 struct nlattr *nla_grps; 1319 struct nlattr *nest; 1320 1321 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 1322 if (hdr == NULL) 1323 return -1; 1324 1325 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 1326 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 1327 goto nla_put_failure; 1328 1329 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 1330 if (nla_grps == NULL) 1331 goto nla_put_failure; 1332 1333 nest = nla_nest_start_noflag(skb, 1); 1334 if (nest == NULL) 1335 goto nla_put_failure; 1336 1337 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 1338 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 1339 grp->name)) 1340 goto nla_put_failure; 1341 1342 nla_nest_end(skb, nest); 1343 nla_nest_end(skb, nla_grps); 1344 1345 genlmsg_end(skb, hdr); 1346 return 0; 1347 1348 nla_put_failure: 1349 genlmsg_cancel(skb, hdr); 1350 return -EMSGSIZE; 1351 } 1352 1353 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 1354 { 1355 int n = 0; 1356 struct genl_family *rt; 1357 struct net *net = sock_net(skb->sk); 1358 int fams_to_skip = cb->args[0]; 1359 unsigned int id; 1360 int err = 0; 1361 1362 idr_for_each_entry(&genl_fam_idr, rt, id) { 1363 if (!rt->netnsok && !net_eq(net, &init_net)) 1364 continue; 1365 1366 if (n++ < fams_to_skip) 1367 continue; 1368 1369 err = ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 1370 cb->nlh->nlmsg_seq, NLM_F_MULTI, 1371 skb, CTRL_CMD_NEWFAMILY); 1372 if (err) { 1373 n--; 1374 break; 1375 } 1376 } 1377 1378 cb->args[0] = n; 1379 return err; 1380 } 1381 1382 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, 1383 u32 portid, int seq, u8 cmd) 1384 { 1385 struct sk_buff *skb; 1386 int err; 1387 1388 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1389 if (skb == NULL) 1390 return ERR_PTR(-ENOBUFS); 1391 1392 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 1393 if (err < 0) { 1394 nlmsg_free(skb); 1395 return ERR_PTR(err); 1396 } 1397 1398 return skb; 1399 } 1400 1401 static struct sk_buff * 1402 ctrl_build_mcgrp_msg(const struct genl_family *family, 1403 const struct genl_multicast_group *grp, 1404 int grp_id, u32 portid, int seq, u8 cmd) 1405 { 1406 struct sk_buff *skb; 1407 int err; 1408 1409 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1410 if (skb == NULL) 1411 return ERR_PTR(-ENOBUFS); 1412 1413 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 1414 seq, 0, skb, cmd); 1415 if (err < 0) { 1416 nlmsg_free(skb); 1417 return ERR_PTR(err); 1418 } 1419 1420 return skb; 1421 } 1422 1423 static const struct nla_policy ctrl_policy_family[] = { 1424 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 1425 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 1426 .len = GENL_NAMSIZ - 1 }, 1427 }; 1428 1429 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 1430 { 1431 struct sk_buff *msg; 1432 const struct genl_family *res = NULL; 1433 int err = -EINVAL; 1434 1435 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 1436 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 1437 res = genl_family_find_byid(id); 1438 err = -ENOENT; 1439 } 1440 1441 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 1442 char *name; 1443 1444 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 1445 res = genl_family_find_byname(name); 1446 #ifdef CONFIG_MODULES 1447 if (res == NULL) { 1448 genl_unlock(); 1449 up_read(&cb_lock); 1450 request_module("net-pf-%d-proto-%d-family-%s", 1451 PF_NETLINK, NETLINK_GENERIC, name); 1452 down_read(&cb_lock); 1453 genl_lock(); 1454 res = genl_family_find_byname(name); 1455 } 1456 #endif 1457 err = -ENOENT; 1458 } 1459 1460 if (res == NULL) 1461 return err; 1462 1463 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 1464 /* family doesn't exist here */ 1465 return -ENOENT; 1466 } 1467 1468 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 1469 CTRL_CMD_NEWFAMILY); 1470 if (IS_ERR(msg)) 1471 return PTR_ERR(msg); 1472 1473 return genlmsg_reply(msg, info); 1474 } 1475 1476 static int genl_ctrl_event(int event, const struct genl_family *family, 1477 const struct genl_multicast_group *grp, 1478 int grp_id) 1479 { 1480 struct sk_buff *msg; 1481 1482 /* genl is still initialising */ 1483 if (!init_net.genl_sock) 1484 return 0; 1485 1486 switch (event) { 1487 case CTRL_CMD_NEWFAMILY: 1488 case CTRL_CMD_DELFAMILY: 1489 WARN_ON(grp); 1490 msg = ctrl_build_family_msg(family, 0, 0, event); 1491 break; 1492 case CTRL_CMD_NEWMCAST_GRP: 1493 case CTRL_CMD_DELMCAST_GRP: 1494 BUG_ON(!grp); 1495 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 1496 break; 1497 default: 1498 return -EINVAL; 1499 } 1500 1501 if (IS_ERR(msg)) 1502 return PTR_ERR(msg); 1503 1504 if (!family->netnsok) { 1505 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 1506 0, GFP_KERNEL); 1507 } else { 1508 rcu_read_lock(); 1509 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 1510 0, GFP_ATOMIC); 1511 rcu_read_unlock(); 1512 } 1513 1514 return 0; 1515 } 1516 1517 struct ctrl_dump_policy_ctx { 1518 struct netlink_policy_dump_state *state; 1519 const struct genl_family *rt; 1520 struct genl_op_iter *op_iter; 1521 u32 op; 1522 u16 fam_id; 1523 u8 dump_map:1, 1524 single_op:1; 1525 }; 1526 1527 static const struct nla_policy ctrl_policy_policy[] = { 1528 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 1529 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 1530 .len = GENL_NAMSIZ - 1 }, 1531 [CTRL_ATTR_OP] = { .type = NLA_U32 }, 1532 }; 1533 1534 static int ctrl_dumppolicy_start(struct netlink_callback *cb) 1535 { 1536 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 1537 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; 1538 struct nlattr **tb = info->info.attrs; 1539 const struct genl_family *rt; 1540 struct genl_op_iter i; 1541 int err; 1542 1543 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx)); 1544 1545 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME]) 1546 return -EINVAL; 1547 1548 if (tb[CTRL_ATTR_FAMILY_ID]) { 1549 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); 1550 } else { 1551 rt = genl_family_find_byname( 1552 nla_data(tb[CTRL_ATTR_FAMILY_NAME])); 1553 if (!rt) 1554 return -ENOENT; 1555 ctx->fam_id = rt->id; 1556 } 1557 1558 rt = genl_family_find_byid(ctx->fam_id); 1559 if (!rt) 1560 return -ENOENT; 1561 1562 ctx->rt = rt; 1563 1564 if (tb[CTRL_ATTR_OP]) { 1565 struct genl_split_ops doit, dump; 1566 1567 ctx->single_op = true; 1568 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]); 1569 1570 err = genl_get_cmd_both(ctx->op, rt, &doit, &dump); 1571 if (err) { 1572 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]); 1573 return err; 1574 } 1575 1576 if (doit.policy) { 1577 err = netlink_policy_dump_add_policy(&ctx->state, 1578 doit.policy, 1579 doit.maxattr); 1580 if (err) 1581 goto err_free_state; 1582 } 1583 if (dump.policy) { 1584 err = netlink_policy_dump_add_policy(&ctx->state, 1585 dump.policy, 1586 dump.maxattr); 1587 if (err) 1588 goto err_free_state; 1589 } 1590 1591 if (!ctx->state) 1592 return -ENODATA; 1593 1594 ctx->dump_map = 1; 1595 return 0; 1596 } 1597 1598 ctx->op_iter = kmalloc(sizeof(*ctx->op_iter), GFP_KERNEL); 1599 if (!ctx->op_iter) 1600 return -ENOMEM; 1601 1602 genl_op_iter_init(rt, ctx->op_iter); 1603 ctx->dump_map = genl_op_iter_next(ctx->op_iter); 1604 1605 for (genl_op_iter_init(rt, &i); genl_op_iter_next(&i); ) { 1606 if (i.doit.policy) { 1607 err = netlink_policy_dump_add_policy(&ctx->state, 1608 i.doit.policy, 1609 i.doit.maxattr); 1610 if (err) 1611 goto err_free_state; 1612 } 1613 if (i.dumpit.policy) { 1614 err = netlink_policy_dump_add_policy(&ctx->state, 1615 i.dumpit.policy, 1616 i.dumpit.maxattr); 1617 if (err) 1618 goto err_free_state; 1619 } 1620 } 1621 1622 if (!ctx->state) { 1623 err = -ENODATA; 1624 goto err_free_op_iter; 1625 } 1626 return 0; 1627 1628 err_free_state: 1629 netlink_policy_dump_free(ctx->state); 1630 err_free_op_iter: 1631 kfree(ctx->op_iter); 1632 return err; 1633 } 1634 1635 static void *ctrl_dumppolicy_prep(struct sk_buff *skb, 1636 struct netlink_callback *cb) 1637 { 1638 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; 1639 void *hdr; 1640 1641 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, 1642 cb->nlh->nlmsg_seq, &genl_ctrl, 1643 NLM_F_MULTI, CTRL_CMD_GETPOLICY); 1644 if (!hdr) 1645 return NULL; 1646 1647 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id)) 1648 return NULL; 1649 1650 return hdr; 1651 } 1652 1653 static int ctrl_dumppolicy_put_op(struct sk_buff *skb, 1654 struct netlink_callback *cb, 1655 struct genl_split_ops *doit, 1656 struct genl_split_ops *dumpit) 1657 { 1658 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; 1659 struct nlattr *nest_pol, *nest_op; 1660 void *hdr; 1661 int idx; 1662 1663 /* skip if we have nothing to show */ 1664 if (!doit->policy && !dumpit->policy) 1665 return 0; 1666 1667 hdr = ctrl_dumppolicy_prep(skb, cb); 1668 if (!hdr) 1669 return -ENOBUFS; 1670 1671 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY); 1672 if (!nest_pol) 1673 goto err; 1674 1675 nest_op = nla_nest_start(skb, doit->cmd); 1676 if (!nest_op) 1677 goto err; 1678 1679 if (doit->policy) { 1680 idx = netlink_policy_dump_get_policy_idx(ctx->state, 1681 doit->policy, 1682 doit->maxattr); 1683 1684 if (nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx)) 1685 goto err; 1686 } 1687 if (dumpit->policy) { 1688 idx = netlink_policy_dump_get_policy_idx(ctx->state, 1689 dumpit->policy, 1690 dumpit->maxattr); 1691 1692 if (nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx)) 1693 goto err; 1694 } 1695 1696 nla_nest_end(skb, nest_op); 1697 nla_nest_end(skb, nest_pol); 1698 genlmsg_end(skb, hdr); 1699 1700 return 0; 1701 err: 1702 genlmsg_cancel(skb, hdr); 1703 return -ENOBUFS; 1704 } 1705 1706 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 1707 { 1708 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; 1709 void *hdr; 1710 1711 if (ctx->dump_map) { 1712 if (ctx->single_op) { 1713 struct genl_split_ops doit, dumpit; 1714 1715 if (WARN_ON(genl_get_cmd_both(ctx->op, ctx->rt, 1716 &doit, &dumpit))) 1717 return -ENOENT; 1718 1719 if (ctrl_dumppolicy_put_op(skb, cb, &doit, &dumpit)) 1720 return skb->len; 1721 1722 /* done with the per-op policy index list */ 1723 ctx->dump_map = 0; 1724 } 1725 1726 while (ctx->dump_map) { 1727 if (ctrl_dumppolicy_put_op(skb, cb, 1728 &ctx->op_iter->doit, 1729 &ctx->op_iter->dumpit)) 1730 return skb->len; 1731 1732 ctx->dump_map = genl_op_iter_next(ctx->op_iter); 1733 } 1734 } 1735 1736 while (netlink_policy_dump_loop(ctx->state)) { 1737 struct nlattr *nest; 1738 1739 hdr = ctrl_dumppolicy_prep(skb, cb); 1740 if (!hdr) 1741 goto nla_put_failure; 1742 1743 nest = nla_nest_start(skb, CTRL_ATTR_POLICY); 1744 if (!nest) 1745 goto nla_put_failure; 1746 1747 if (netlink_policy_dump_write(skb, ctx->state)) 1748 goto nla_put_failure; 1749 1750 nla_nest_end(skb, nest); 1751 1752 genlmsg_end(skb, hdr); 1753 } 1754 1755 return skb->len; 1756 1757 nla_put_failure: 1758 genlmsg_cancel(skb, hdr); 1759 return skb->len; 1760 } 1761 1762 static int ctrl_dumppolicy_done(struct netlink_callback *cb) 1763 { 1764 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; 1765 1766 kfree(ctx->op_iter); 1767 netlink_policy_dump_free(ctx->state); 1768 return 0; 1769 } 1770 1771 static const struct genl_split_ops genl_ctrl_ops[] = { 1772 { 1773 .cmd = CTRL_CMD_GETFAMILY, 1774 .validate = GENL_DONT_VALIDATE_STRICT, 1775 .policy = ctrl_policy_family, 1776 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1, 1777 .doit = ctrl_getfamily, 1778 .flags = GENL_CMD_CAP_DO, 1779 }, 1780 { 1781 .cmd = CTRL_CMD_GETFAMILY, 1782 .validate = GENL_DONT_VALIDATE_DUMP, 1783 .policy = ctrl_policy_family, 1784 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1, 1785 .dumpit = ctrl_dumpfamily, 1786 .flags = GENL_CMD_CAP_DUMP, 1787 }, 1788 { 1789 .cmd = CTRL_CMD_GETPOLICY, 1790 .policy = ctrl_policy_policy, 1791 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1, 1792 .start = ctrl_dumppolicy_start, 1793 .dumpit = ctrl_dumppolicy, 1794 .done = ctrl_dumppolicy_done, 1795 .flags = GENL_CMD_CAP_DUMP, 1796 }, 1797 }; 1798 1799 static const struct genl_multicast_group genl_ctrl_groups[] = { 1800 { .name = "notify", }, 1801 }; 1802 1803 static struct genl_family genl_ctrl __ro_after_init = { 1804 .module = THIS_MODULE, 1805 .split_ops = genl_ctrl_ops, 1806 .n_split_ops = ARRAY_SIZE(genl_ctrl_ops), 1807 .resv_start_op = CTRL_CMD_GETPOLICY + 1, 1808 .mcgrps = genl_ctrl_groups, 1809 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), 1810 .id = GENL_ID_CTRL, 1811 .name = "nlctrl", 1812 .version = 0x2, 1813 .netnsok = true, 1814 }; 1815 1816 static int genl_bind(struct net *net, int group) 1817 { 1818 const struct genl_family *family; 1819 unsigned int id; 1820 int ret = 0; 1821 1822 down_read(&cb_lock); 1823 1824 idr_for_each_entry(&genl_fam_idr, family, id) { 1825 const struct genl_multicast_group *grp; 1826 int i; 1827 1828 if (family->n_mcgrps == 0) 1829 continue; 1830 1831 i = group - family->mcgrp_offset; 1832 if (i < 0 || i >= family->n_mcgrps) 1833 continue; 1834 1835 grp = &family->mcgrps[i]; 1836 if ((grp->flags & GENL_MCAST_CAP_NET_ADMIN) && 1837 !ns_capable(net->user_ns, CAP_NET_ADMIN)) 1838 ret = -EPERM; 1839 if ((grp->flags & GENL_MCAST_CAP_SYS_ADMIN) && 1840 !ns_capable(net->user_ns, CAP_SYS_ADMIN)) 1841 ret = -EPERM; 1842 1843 if (family->bind) 1844 family->bind(i); 1845 1846 break; 1847 } 1848 1849 up_read(&cb_lock); 1850 return ret; 1851 } 1852 1853 static void genl_unbind(struct net *net, int group) 1854 { 1855 const struct genl_family *family; 1856 unsigned int id; 1857 1858 down_read(&cb_lock); 1859 1860 idr_for_each_entry(&genl_fam_idr, family, id) { 1861 int i; 1862 1863 if (family->n_mcgrps == 0) 1864 continue; 1865 1866 i = group - family->mcgrp_offset; 1867 if (i < 0 || i >= family->n_mcgrps) 1868 continue; 1869 1870 if (family->unbind) 1871 family->unbind(i); 1872 1873 break; 1874 } 1875 1876 up_read(&cb_lock); 1877 } 1878 1879 static int __net_init genl_pernet_init(struct net *net) 1880 { 1881 struct netlink_kernel_cfg cfg = { 1882 .input = genl_rcv, 1883 .flags = NL_CFG_F_NONROOT_RECV, 1884 .bind = genl_bind, 1885 .unbind = genl_unbind, 1886 .release = genl_release, 1887 }; 1888 1889 /* we'll bump the group number right afterwards */ 1890 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1891 1892 if (!net->genl_sock && net_eq(net, &init_net)) 1893 panic("GENL: Cannot initialize generic netlink\n"); 1894 1895 if (!net->genl_sock) 1896 return -ENOMEM; 1897 1898 return 0; 1899 } 1900 1901 static void __net_exit genl_pernet_exit(struct net *net) 1902 { 1903 netlink_kernel_release(net->genl_sock); 1904 net->genl_sock = NULL; 1905 } 1906 1907 static struct pernet_operations genl_pernet_ops = { 1908 .init = genl_pernet_init, 1909 .exit = genl_pernet_exit, 1910 }; 1911 1912 static int __init genl_init(void) 1913 { 1914 int err; 1915 1916 err = genl_register_family(&genl_ctrl); 1917 if (err < 0) 1918 goto problem; 1919 1920 err = register_pernet_subsys(&genl_pernet_ops); 1921 if (err) 1922 goto problem; 1923 1924 return 0; 1925 1926 problem: 1927 panic("GENL: Cannot register controller: %d\n", err); 1928 } 1929 1930 core_initcall(genl_init); 1931 1932 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1933 gfp_t flags) 1934 { 1935 struct sk_buff *tmp; 1936 struct net *net, *prev = NULL; 1937 bool delivered = false; 1938 int err; 1939 1940 for_each_net_rcu(net) { 1941 if (prev) { 1942 tmp = skb_clone(skb, flags); 1943 if (!tmp) { 1944 err = -ENOMEM; 1945 goto error; 1946 } 1947 err = nlmsg_multicast(prev->genl_sock, tmp, 1948 portid, group, flags); 1949 if (!err) 1950 delivered = true; 1951 else if (err != -ESRCH) 1952 goto error; 1953 } 1954 1955 prev = net; 1956 } 1957 1958 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1959 if (!err) 1960 delivered = true; 1961 else if (err != -ESRCH) 1962 return err; 1963 return delivered ? 0 : -ESRCH; 1964 error: 1965 kfree_skb(skb); 1966 return err; 1967 } 1968 1969 int genlmsg_multicast_allns(const struct genl_family *family, 1970 struct sk_buff *skb, u32 portid, 1971 unsigned int group, gfp_t flags) 1972 { 1973 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1974 return -EINVAL; 1975 1976 group = family->mcgrp_offset + group; 1977 return genlmsg_mcast(skb, portid, group, flags); 1978 } 1979 EXPORT_SYMBOL(genlmsg_multicast_allns); 1980 1981 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 1982 struct genl_info *info, u32 group, gfp_t flags) 1983 { 1984 struct net *net = genl_info_net(info); 1985 struct sock *sk = net->genl_sock; 1986 1987 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1988 return; 1989 1990 group = family->mcgrp_offset + group; 1991 nlmsg_notify(sk, skb, info->snd_portid, group, 1992 nlmsg_report(info->nlhdr), flags); 1993 } 1994 EXPORT_SYMBOL(genl_notify); 1995