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 struct genl_start_context { 517 const struct genl_family *family; 518 struct nlmsghdr *nlh; 519 struct netlink_ext_ack *extack; 520 const struct genl_ops *ops; 521 int hdrlen; 522 }; 523 524 static int genl_start(struct netlink_callback *cb) 525 { 526 struct genl_start_context *ctx = cb->data; 527 const struct genl_ops *ops = ctx->ops; 528 struct genl_dumpit_info *info; 529 struct nlattr **attrs = NULL; 530 int rc = 0; 531 532 if (ops->validate & GENL_DONT_VALIDATE_DUMP) 533 goto no_attrs; 534 535 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen)) 536 return -EINVAL; 537 538 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack, 539 ops, ctx->hdrlen, 540 GENL_DONT_VALIDATE_DUMP_STRICT, 541 true); 542 if (IS_ERR(attrs)) 543 return PTR_ERR(attrs); 544 545 no_attrs: 546 info = genl_dumpit_info_alloc(); 547 if (!info) { 548 kfree(attrs); 549 return -ENOMEM; 550 } 551 info->family = ctx->family; 552 info->ops = ops; 553 info->attrs = attrs; 554 555 cb->data = info; 556 if (ops->start) { 557 if (!ctx->family->parallel_ops) 558 genl_lock(); 559 rc = ops->start(cb); 560 if (!ctx->family->parallel_ops) 561 genl_unlock(); 562 } 563 564 if (rc) { 565 kfree(attrs); 566 genl_dumpit_info_free(info); 567 cb->data = NULL; 568 } 569 return rc; 570 } 571 572 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 573 { 574 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 575 int rc; 576 577 genl_lock(); 578 rc = ops->dumpit(skb, cb); 579 genl_unlock(); 580 return rc; 581 } 582 583 static int genl_lock_done(struct netlink_callback *cb) 584 { 585 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 586 const struct genl_ops *ops = info->ops; 587 int rc = 0; 588 589 if (ops->done) { 590 genl_lock(); 591 rc = ops->done(cb); 592 genl_unlock(); 593 } 594 genl_family_rcv_msg_attrs_free(info->family, info->attrs, false); 595 genl_dumpit_info_free(info); 596 return rc; 597 } 598 599 static int genl_parallel_done(struct netlink_callback *cb) 600 { 601 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 602 const struct genl_ops *ops = info->ops; 603 int rc = 0; 604 605 if (ops->done) 606 rc = ops->done(cb); 607 genl_family_rcv_msg_attrs_free(info->family, info->attrs, true); 608 genl_dumpit_info_free(info); 609 return rc; 610 } 611 612 static int genl_family_rcv_msg_dumpit(const struct genl_family *family, 613 struct sk_buff *skb, 614 struct nlmsghdr *nlh, 615 struct netlink_ext_ack *extack, 616 const struct genl_ops *ops, 617 int hdrlen, struct net *net) 618 { 619 struct genl_start_context ctx; 620 int err; 621 622 if (!ops->dumpit) 623 return -EOPNOTSUPP; 624 625 ctx.family = family; 626 ctx.nlh = nlh; 627 ctx.extack = extack; 628 ctx.ops = ops; 629 ctx.hdrlen = hdrlen; 630 631 if (!family->parallel_ops) { 632 struct netlink_dump_control c = { 633 .module = family->module, 634 .data = &ctx, 635 .start = genl_start, 636 .dump = genl_lock_dumpit, 637 .done = genl_lock_done, 638 }; 639 640 genl_unlock(); 641 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 642 genl_lock(); 643 } else { 644 struct netlink_dump_control c = { 645 .module = family->module, 646 .data = &ctx, 647 .start = genl_start, 648 .dump = ops->dumpit, 649 .done = genl_parallel_done, 650 }; 651 652 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 653 } 654 655 return err; 656 } 657 658 static int genl_family_rcv_msg_doit(const struct genl_family *family, 659 struct sk_buff *skb, 660 struct nlmsghdr *nlh, 661 struct netlink_ext_ack *extack, 662 const struct genl_ops *ops, 663 int hdrlen, struct net *net) 664 { 665 struct nlattr **attrbuf; 666 struct genl_info info; 667 int err; 668 669 if (!ops->doit) 670 return -EOPNOTSUPP; 671 672 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 673 ops, hdrlen, 674 GENL_DONT_VALIDATE_STRICT, 675 family->parallel_ops); 676 if (IS_ERR(attrbuf)) 677 return PTR_ERR(attrbuf); 678 679 info.snd_seq = nlh->nlmsg_seq; 680 info.snd_portid = NETLINK_CB(skb).portid; 681 info.nlhdr = nlh; 682 info.genlhdr = nlmsg_data(nlh); 683 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 684 info.attrs = attrbuf; 685 info.extack = extack; 686 genl_info_net_set(&info, net); 687 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 688 689 if (family->pre_doit) { 690 err = family->pre_doit(ops, skb, &info); 691 if (err) 692 goto out; 693 } 694 695 err = ops->doit(skb, &info); 696 697 if (family->post_doit) 698 family->post_doit(ops, skb, &info); 699 700 out: 701 genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops); 702 703 return err; 704 } 705 706 static int genl_family_rcv_msg(const struct genl_family *family, 707 struct sk_buff *skb, 708 struct nlmsghdr *nlh, 709 struct netlink_ext_ack *extack) 710 { 711 const struct genl_ops *ops; 712 struct net *net = sock_net(skb->sk); 713 struct genlmsghdr *hdr = nlmsg_data(nlh); 714 int hdrlen; 715 716 /* this family doesn't exist in this netns */ 717 if (!family->netnsok && !net_eq(net, &init_net)) 718 return -ENOENT; 719 720 hdrlen = GENL_HDRLEN + family->hdrsize; 721 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 722 return -EINVAL; 723 724 ops = genl_get_cmd(hdr->cmd, family); 725 if (ops == NULL) 726 return -EOPNOTSUPP; 727 728 if ((ops->flags & GENL_ADMIN_PERM) && 729 !netlink_capable(skb, CAP_NET_ADMIN)) 730 return -EPERM; 731 732 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 733 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 734 return -EPERM; 735 736 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) 737 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, 738 ops, hdrlen, net); 739 else 740 return genl_family_rcv_msg_doit(family, skb, nlh, extack, 741 ops, hdrlen, net); 742 } 743 744 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 745 struct netlink_ext_ack *extack) 746 { 747 const struct genl_family *family; 748 int err; 749 750 family = genl_family_find_byid(nlh->nlmsg_type); 751 if (family == NULL) 752 return -ENOENT; 753 754 if (!family->parallel_ops) 755 genl_lock(); 756 757 err = genl_family_rcv_msg(family, skb, nlh, extack); 758 759 if (!family->parallel_ops) 760 genl_unlock(); 761 762 return err; 763 } 764 765 static void genl_rcv(struct sk_buff *skb) 766 { 767 down_read(&cb_lock); 768 netlink_rcv_skb(skb, &genl_rcv_msg); 769 up_read(&cb_lock); 770 } 771 772 /************************************************************************** 773 * Controller 774 **************************************************************************/ 775 776 static struct genl_family genl_ctrl; 777 778 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 779 u32 flags, struct sk_buff *skb, u8 cmd) 780 { 781 void *hdr; 782 783 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 784 if (hdr == NULL) 785 return -1; 786 787 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 788 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 789 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 790 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 791 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 792 goto nla_put_failure; 793 794 if (family->n_ops) { 795 struct nlattr *nla_ops; 796 int i; 797 798 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS); 799 if (nla_ops == NULL) 800 goto nla_put_failure; 801 802 for (i = 0; i < family->n_ops; i++) { 803 struct nlattr *nest; 804 const struct genl_ops *ops = &family->ops[i]; 805 u32 op_flags = ops->flags; 806 807 if (ops->dumpit) 808 op_flags |= GENL_CMD_CAP_DUMP; 809 if (ops->doit) 810 op_flags |= GENL_CMD_CAP_DO; 811 if (family->policy) 812 op_flags |= GENL_CMD_CAP_HASPOL; 813 814 nest = nla_nest_start_noflag(skb, i + 1); 815 if (nest == NULL) 816 goto nla_put_failure; 817 818 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 819 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 820 goto nla_put_failure; 821 822 nla_nest_end(skb, nest); 823 } 824 825 nla_nest_end(skb, nla_ops); 826 } 827 828 if (family->n_mcgrps) { 829 struct nlattr *nla_grps; 830 int i; 831 832 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 833 if (nla_grps == NULL) 834 goto nla_put_failure; 835 836 for (i = 0; i < family->n_mcgrps; i++) { 837 struct nlattr *nest; 838 const struct genl_multicast_group *grp; 839 840 grp = &family->mcgrps[i]; 841 842 nest = nla_nest_start_noflag(skb, i + 1); 843 if (nest == NULL) 844 goto nla_put_failure; 845 846 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 847 family->mcgrp_offset + i) || 848 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 849 grp->name)) 850 goto nla_put_failure; 851 852 nla_nest_end(skb, nest); 853 } 854 nla_nest_end(skb, nla_grps); 855 } 856 857 genlmsg_end(skb, hdr); 858 return 0; 859 860 nla_put_failure: 861 genlmsg_cancel(skb, hdr); 862 return -EMSGSIZE; 863 } 864 865 static int ctrl_fill_mcgrp_info(const struct genl_family *family, 866 const struct genl_multicast_group *grp, 867 int grp_id, u32 portid, u32 seq, u32 flags, 868 struct sk_buff *skb, u8 cmd) 869 { 870 void *hdr; 871 struct nlattr *nla_grps; 872 struct nlattr *nest; 873 874 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 875 if (hdr == NULL) 876 return -1; 877 878 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 879 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 880 goto nla_put_failure; 881 882 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 883 if (nla_grps == NULL) 884 goto nla_put_failure; 885 886 nest = nla_nest_start_noflag(skb, 1); 887 if (nest == NULL) 888 goto nla_put_failure; 889 890 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 891 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 892 grp->name)) 893 goto nla_put_failure; 894 895 nla_nest_end(skb, nest); 896 nla_nest_end(skb, nla_grps); 897 898 genlmsg_end(skb, hdr); 899 return 0; 900 901 nla_put_failure: 902 genlmsg_cancel(skb, hdr); 903 return -EMSGSIZE; 904 } 905 906 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 907 { 908 int n = 0; 909 struct genl_family *rt; 910 struct net *net = sock_net(skb->sk); 911 int fams_to_skip = cb->args[0]; 912 unsigned int id; 913 914 idr_for_each_entry(&genl_fam_idr, rt, id) { 915 if (!rt->netnsok && !net_eq(net, &init_net)) 916 continue; 917 918 if (n++ < fams_to_skip) 919 continue; 920 921 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 922 cb->nlh->nlmsg_seq, NLM_F_MULTI, 923 skb, CTRL_CMD_NEWFAMILY) < 0) { 924 n--; 925 break; 926 } 927 } 928 929 cb->args[0] = n; 930 return skb->len; 931 } 932 933 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, 934 u32 portid, int seq, u8 cmd) 935 { 936 struct sk_buff *skb; 937 int err; 938 939 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 940 if (skb == NULL) 941 return ERR_PTR(-ENOBUFS); 942 943 err = ctrl_fill_info(family, portid, 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 struct sk_buff * 953 ctrl_build_mcgrp_msg(const struct genl_family *family, 954 const struct genl_multicast_group *grp, 955 int grp_id, u32 portid, int seq, u8 cmd) 956 { 957 struct sk_buff *skb; 958 int err; 959 960 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 961 if (skb == NULL) 962 return ERR_PTR(-ENOBUFS); 963 964 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 965 seq, 0, skb, cmd); 966 if (err < 0) { 967 nlmsg_free(skb); 968 return ERR_PTR(err); 969 } 970 971 return skb; 972 } 973 974 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 975 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 976 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 977 .len = GENL_NAMSIZ - 1 }, 978 }; 979 980 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 981 { 982 struct sk_buff *msg; 983 const struct genl_family *res = NULL; 984 int err = -EINVAL; 985 986 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 987 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 988 res = genl_family_find_byid(id); 989 err = -ENOENT; 990 } 991 992 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 993 char *name; 994 995 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 996 res = genl_family_find_byname(name); 997 #ifdef CONFIG_MODULES 998 if (res == NULL) { 999 genl_unlock(); 1000 up_read(&cb_lock); 1001 request_module("net-pf-%d-proto-%d-family-%s", 1002 PF_NETLINK, NETLINK_GENERIC, name); 1003 down_read(&cb_lock); 1004 genl_lock(); 1005 res = genl_family_find_byname(name); 1006 } 1007 #endif 1008 err = -ENOENT; 1009 } 1010 1011 if (res == NULL) 1012 return err; 1013 1014 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 1015 /* family doesn't exist here */ 1016 return -ENOENT; 1017 } 1018 1019 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 1020 CTRL_CMD_NEWFAMILY); 1021 if (IS_ERR(msg)) 1022 return PTR_ERR(msg); 1023 1024 return genlmsg_reply(msg, info); 1025 } 1026 1027 static int genl_ctrl_event(int event, const struct genl_family *family, 1028 const struct genl_multicast_group *grp, 1029 int grp_id) 1030 { 1031 struct sk_buff *msg; 1032 1033 /* genl is still initialising */ 1034 if (!init_net.genl_sock) 1035 return 0; 1036 1037 switch (event) { 1038 case CTRL_CMD_NEWFAMILY: 1039 case CTRL_CMD_DELFAMILY: 1040 WARN_ON(grp); 1041 msg = ctrl_build_family_msg(family, 0, 0, event); 1042 break; 1043 case CTRL_CMD_NEWMCAST_GRP: 1044 case CTRL_CMD_DELMCAST_GRP: 1045 BUG_ON(!grp); 1046 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 1047 break; 1048 default: 1049 return -EINVAL; 1050 } 1051 1052 if (IS_ERR(msg)) 1053 return PTR_ERR(msg); 1054 1055 if (!family->netnsok) { 1056 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 1057 0, GFP_KERNEL); 1058 } else { 1059 rcu_read_lock(); 1060 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 1061 0, GFP_ATOMIC); 1062 rcu_read_unlock(); 1063 } 1064 1065 return 0; 1066 } 1067 1068 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 1069 { 1070 const struct genl_family *rt; 1071 unsigned int fam_id = cb->args[0]; 1072 int err; 1073 1074 if (!fam_id) { 1075 struct nlattr *tb[CTRL_ATTR_MAX + 1]; 1076 1077 err = genlmsg_parse(cb->nlh, &genl_ctrl, tb, 1078 genl_ctrl.maxattr, 1079 genl_ctrl.policy, cb->extack); 1080 if (err) 1081 return err; 1082 1083 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME]) 1084 return -EINVAL; 1085 1086 if (tb[CTRL_ATTR_FAMILY_ID]) { 1087 fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); 1088 } else { 1089 rt = genl_family_find_byname( 1090 nla_data(tb[CTRL_ATTR_FAMILY_NAME])); 1091 if (!rt) 1092 return -ENOENT; 1093 fam_id = rt->id; 1094 } 1095 } 1096 1097 rt = genl_family_find_byid(fam_id); 1098 if (!rt) 1099 return -ENOENT; 1100 1101 if (!rt->policy) 1102 return -ENODATA; 1103 1104 err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]); 1105 if (err) 1106 return err; 1107 1108 while (netlink_policy_dump_loop(&cb->args[1])) { 1109 void *hdr; 1110 struct nlattr *nest; 1111 1112 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, 1113 cb->nlh->nlmsg_seq, &genl_ctrl, 1114 NLM_F_MULTI, CTRL_CMD_GETPOLICY); 1115 if (!hdr) 1116 goto nla_put_failure; 1117 1118 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id)) 1119 goto nla_put_failure; 1120 1121 nest = nla_nest_start(skb, CTRL_ATTR_POLICY); 1122 if (!nest) 1123 goto nla_put_failure; 1124 1125 if (netlink_policy_dump_write(skb, cb->args[1])) 1126 goto nla_put_failure; 1127 1128 nla_nest_end(skb, nest); 1129 1130 genlmsg_end(skb, hdr); 1131 continue; 1132 1133 nla_put_failure: 1134 genlmsg_cancel(skb, hdr); 1135 break; 1136 } 1137 1138 cb->args[0] = fam_id; 1139 return skb->len; 1140 } 1141 1142 static const struct genl_ops genl_ctrl_ops[] = { 1143 { 1144 .cmd = CTRL_CMD_GETFAMILY, 1145 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1146 .doit = ctrl_getfamily, 1147 .dumpit = ctrl_dumpfamily, 1148 }, 1149 { 1150 .cmd = CTRL_CMD_GETPOLICY, 1151 .dumpit = ctrl_dumppolicy, 1152 }, 1153 }; 1154 1155 static const struct genl_multicast_group genl_ctrl_groups[] = { 1156 { .name = "notify", }, 1157 }; 1158 1159 static struct genl_family genl_ctrl __ro_after_init = { 1160 .module = THIS_MODULE, 1161 .ops = genl_ctrl_ops, 1162 .n_ops = ARRAY_SIZE(genl_ctrl_ops), 1163 .mcgrps = genl_ctrl_groups, 1164 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), 1165 .id = GENL_ID_CTRL, 1166 .name = "nlctrl", 1167 .version = 0x2, 1168 .maxattr = CTRL_ATTR_MAX, 1169 .policy = ctrl_policy, 1170 .netnsok = true, 1171 }; 1172 1173 static int genl_bind(struct net *net, int group) 1174 { 1175 struct genl_family *f; 1176 int err = -ENOENT; 1177 unsigned int id; 1178 1179 down_read(&cb_lock); 1180 1181 idr_for_each_entry(&genl_fam_idr, f, id) { 1182 if (group >= f->mcgrp_offset && 1183 group < f->mcgrp_offset + f->n_mcgrps) { 1184 int fam_grp = group - f->mcgrp_offset; 1185 1186 if (!f->netnsok && net != &init_net) 1187 err = -ENOENT; 1188 else if (f->mcast_bind) 1189 err = f->mcast_bind(net, fam_grp); 1190 else 1191 err = 0; 1192 break; 1193 } 1194 } 1195 up_read(&cb_lock); 1196 1197 return err; 1198 } 1199 1200 static void genl_unbind(struct net *net, int group) 1201 { 1202 struct genl_family *f; 1203 unsigned int id; 1204 1205 down_read(&cb_lock); 1206 1207 idr_for_each_entry(&genl_fam_idr, f, id) { 1208 if (group >= f->mcgrp_offset && 1209 group < f->mcgrp_offset + f->n_mcgrps) { 1210 int fam_grp = group - f->mcgrp_offset; 1211 1212 if (f->mcast_unbind) 1213 f->mcast_unbind(net, fam_grp); 1214 break; 1215 } 1216 } 1217 up_read(&cb_lock); 1218 } 1219 1220 static int __net_init genl_pernet_init(struct net *net) 1221 { 1222 struct netlink_kernel_cfg cfg = { 1223 .input = genl_rcv, 1224 .flags = NL_CFG_F_NONROOT_RECV, 1225 .bind = genl_bind, 1226 .unbind = genl_unbind, 1227 }; 1228 1229 /* we'll bump the group number right afterwards */ 1230 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1231 1232 if (!net->genl_sock && net_eq(net, &init_net)) 1233 panic("GENL: Cannot initialize generic netlink\n"); 1234 1235 if (!net->genl_sock) 1236 return -ENOMEM; 1237 1238 return 0; 1239 } 1240 1241 static void __net_exit genl_pernet_exit(struct net *net) 1242 { 1243 netlink_kernel_release(net->genl_sock); 1244 net->genl_sock = NULL; 1245 } 1246 1247 static struct pernet_operations genl_pernet_ops = { 1248 .init = genl_pernet_init, 1249 .exit = genl_pernet_exit, 1250 }; 1251 1252 static int __init genl_init(void) 1253 { 1254 int err; 1255 1256 err = genl_register_family(&genl_ctrl); 1257 if (err < 0) 1258 goto problem; 1259 1260 err = register_pernet_subsys(&genl_pernet_ops); 1261 if (err) 1262 goto problem; 1263 1264 return 0; 1265 1266 problem: 1267 panic("GENL: Cannot register controller: %d\n", err); 1268 } 1269 1270 subsys_initcall(genl_init); 1271 1272 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1273 gfp_t flags) 1274 { 1275 struct sk_buff *tmp; 1276 struct net *net, *prev = NULL; 1277 bool delivered = false; 1278 int err; 1279 1280 for_each_net_rcu(net) { 1281 if (prev) { 1282 tmp = skb_clone(skb, flags); 1283 if (!tmp) { 1284 err = -ENOMEM; 1285 goto error; 1286 } 1287 err = nlmsg_multicast(prev->genl_sock, tmp, 1288 portid, group, flags); 1289 if (!err) 1290 delivered = true; 1291 else if (err != -ESRCH) 1292 goto error; 1293 } 1294 1295 prev = net; 1296 } 1297 1298 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1299 if (!err) 1300 delivered = true; 1301 else if (err != -ESRCH) 1302 return err; 1303 return delivered ? 0 : -ESRCH; 1304 error: 1305 kfree_skb(skb); 1306 return err; 1307 } 1308 1309 int genlmsg_multicast_allns(const struct genl_family *family, 1310 struct sk_buff *skb, u32 portid, 1311 unsigned int group, gfp_t flags) 1312 { 1313 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1314 return -EINVAL; 1315 group = family->mcgrp_offset + group; 1316 return genlmsg_mcast(skb, portid, group, flags); 1317 } 1318 EXPORT_SYMBOL(genlmsg_multicast_allns); 1319 1320 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 1321 struct genl_info *info, u32 group, gfp_t flags) 1322 { 1323 struct net *net = genl_info_net(info); 1324 struct sock *sk = net->genl_sock; 1325 int report = 0; 1326 1327 if (info->nlhdr) 1328 report = nlmsg_report(info->nlhdr); 1329 1330 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1331 return; 1332 group = family->mcgrp_offset + group; 1333 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1334 } 1335 EXPORT_SYMBOL(genl_notify); 1336