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 { 479 enum netlink_validation validate = ops->validate & no_strict_flag ? 480 NL_VALIDATE_LIBERAL : 481 NL_VALIDATE_STRICT; 482 struct nlattr **attrbuf; 483 int err; 484 485 if (!family->maxattr) 486 return NULL; 487 488 if (family->parallel_ops) { 489 attrbuf = kmalloc_array(family->maxattr + 1, 490 sizeof(struct nlattr *), GFP_KERNEL); 491 if (!attrbuf) 492 return ERR_PTR(-ENOMEM); 493 } else { 494 attrbuf = family->attrbuf; 495 } 496 497 err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, 498 family->policy, validate, extack); 499 if (err) { 500 if (family->parallel_ops) 501 kfree(attrbuf); 502 return ERR_PTR(err); 503 } 504 return attrbuf; 505 } 506 507 static void genl_family_rcv_msg_attrs_free(const struct genl_family *family, 508 struct nlattr **attrbuf) 509 { 510 if (family->parallel_ops) 511 kfree(attrbuf); 512 } 513 514 struct genl_start_context { 515 const struct genl_family *family; 516 struct nlmsghdr *nlh; 517 struct netlink_ext_ack *extack; 518 const struct genl_ops *ops; 519 int hdrlen; 520 }; 521 522 static int genl_start(struct netlink_callback *cb) 523 { 524 struct genl_start_context *ctx = cb->data; 525 const struct genl_ops *ops = ctx->ops; 526 struct genl_dumpit_info *info; 527 struct nlattr **attrs = NULL; 528 int rc = 0; 529 530 if (ops->validate & GENL_DONT_VALIDATE_DUMP) 531 goto no_attrs; 532 533 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen)) 534 return -EINVAL; 535 536 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack, 537 ops, ctx->hdrlen, 538 GENL_DONT_VALIDATE_DUMP_STRICT); 539 if (IS_ERR(attrs)) 540 return PTR_ERR(attrs); 541 542 no_attrs: 543 info = genl_dumpit_info_alloc(); 544 if (!info) { 545 genl_family_rcv_msg_attrs_free(ctx->family, attrs); 546 return -ENOMEM; 547 } 548 info->family = ctx->family; 549 info->ops = ops; 550 info->attrs = attrs; 551 552 cb->data = info; 553 if (ops->start) { 554 if (!ctx->family->parallel_ops) 555 genl_lock(); 556 rc = ops->start(cb); 557 if (!ctx->family->parallel_ops) 558 genl_unlock(); 559 } 560 561 if (rc) { 562 genl_family_rcv_msg_attrs_free(info->family, info->attrs); 563 genl_dumpit_info_free(info); 564 cb->data = NULL; 565 } 566 return rc; 567 } 568 569 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 570 { 571 const struct genl_ops *ops = genl_dumpit_info(cb)->ops; 572 int rc; 573 574 genl_lock(); 575 rc = ops->dumpit(skb, cb); 576 genl_unlock(); 577 return rc; 578 } 579 580 static int genl_lock_done(struct netlink_callback *cb) 581 { 582 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 583 const struct genl_ops *ops = info->ops; 584 int rc = 0; 585 586 if (ops->done) { 587 genl_lock(); 588 rc = ops->done(cb); 589 genl_unlock(); 590 } 591 genl_family_rcv_msg_attrs_free(info->family, info->attrs); 592 genl_dumpit_info_free(info); 593 return rc; 594 } 595 596 static int genl_parallel_done(struct netlink_callback *cb) 597 { 598 const struct genl_dumpit_info *info = genl_dumpit_info(cb); 599 const struct genl_ops *ops = info->ops; 600 int rc = 0; 601 602 if (ops->done) 603 rc = ops->done(cb); 604 genl_family_rcv_msg_attrs_free(info->family, info->attrs); 605 genl_dumpit_info_free(info); 606 return rc; 607 } 608 609 static int genl_family_rcv_msg_dumpit(const struct genl_family *family, 610 struct sk_buff *skb, 611 struct nlmsghdr *nlh, 612 struct netlink_ext_ack *extack, 613 const struct genl_ops *ops, 614 int hdrlen, struct net *net) 615 { 616 struct genl_start_context ctx; 617 int err; 618 619 if (!ops->dumpit) 620 return -EOPNOTSUPP; 621 622 ctx.family = family; 623 ctx.nlh = nlh; 624 ctx.extack = extack; 625 ctx.ops = ops; 626 ctx.hdrlen = hdrlen; 627 628 if (!family->parallel_ops) { 629 struct netlink_dump_control c = { 630 .module = family->module, 631 .data = &ctx, 632 .start = genl_start, 633 .dump = genl_lock_dumpit, 634 .done = genl_lock_done, 635 }; 636 637 genl_unlock(); 638 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 639 genl_lock(); 640 } else { 641 struct netlink_dump_control c = { 642 .module = family->module, 643 .data = &ctx, 644 .start = genl_start, 645 .dump = ops->dumpit, 646 .done = genl_parallel_done, 647 }; 648 649 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); 650 } 651 652 return err; 653 } 654 655 static int genl_family_rcv_msg_doit(const struct genl_family *family, 656 struct sk_buff *skb, 657 struct nlmsghdr *nlh, 658 struct netlink_ext_ack *extack, 659 const struct genl_ops *ops, 660 int hdrlen, struct net *net) 661 { 662 struct nlattr **attrbuf; 663 struct genl_info info; 664 int err; 665 666 if (!ops->doit) 667 return -EOPNOTSUPP; 668 669 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, 670 ops, hdrlen, 671 GENL_DONT_VALIDATE_STRICT); 672 if (IS_ERR(attrbuf)) 673 return PTR_ERR(attrbuf); 674 675 info.snd_seq = nlh->nlmsg_seq; 676 info.snd_portid = NETLINK_CB(skb).portid; 677 info.nlhdr = nlh; 678 info.genlhdr = nlmsg_data(nlh); 679 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; 680 info.attrs = attrbuf; 681 info.extack = extack; 682 genl_info_net_set(&info, net); 683 memset(&info.user_ptr, 0, sizeof(info.user_ptr)); 684 685 if (family->pre_doit) { 686 err = family->pre_doit(ops, skb, &info); 687 if (err) 688 goto out; 689 } 690 691 err = ops->doit(skb, &info); 692 693 if (family->post_doit) 694 family->post_doit(ops, skb, &info); 695 696 out: 697 genl_family_rcv_msg_attrs_free(family, attrbuf); 698 699 return err; 700 } 701 702 static int genl_family_rcv_msg(const struct genl_family *family, 703 struct sk_buff *skb, 704 struct nlmsghdr *nlh, 705 struct netlink_ext_ack *extack) 706 { 707 const struct genl_ops *ops; 708 struct net *net = sock_net(skb->sk); 709 struct genlmsghdr *hdr = nlmsg_data(nlh); 710 int hdrlen; 711 712 /* this family doesn't exist in this netns */ 713 if (!family->netnsok && !net_eq(net, &init_net)) 714 return -ENOENT; 715 716 hdrlen = GENL_HDRLEN + family->hdrsize; 717 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) 718 return -EINVAL; 719 720 ops = genl_get_cmd(hdr->cmd, family); 721 if (ops == NULL) 722 return -EOPNOTSUPP; 723 724 if ((ops->flags & GENL_ADMIN_PERM) && 725 !netlink_capable(skb, CAP_NET_ADMIN)) 726 return -EPERM; 727 728 if ((ops->flags & GENL_UNS_ADMIN_PERM) && 729 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 730 return -EPERM; 731 732 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) 733 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, 734 ops, hdrlen, net); 735 else 736 return genl_family_rcv_msg_doit(family, skb, nlh, extack, 737 ops, hdrlen, net); 738 } 739 740 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, 741 struct netlink_ext_ack *extack) 742 { 743 const struct genl_family *family; 744 int err; 745 746 family = genl_family_find_byid(nlh->nlmsg_type); 747 if (family == NULL) 748 return -ENOENT; 749 750 if (!family->parallel_ops) 751 genl_lock(); 752 753 err = genl_family_rcv_msg(family, skb, nlh, extack); 754 755 if (!family->parallel_ops) 756 genl_unlock(); 757 758 return err; 759 } 760 761 static void genl_rcv(struct sk_buff *skb) 762 { 763 down_read(&cb_lock); 764 netlink_rcv_skb(skb, &genl_rcv_msg); 765 up_read(&cb_lock); 766 } 767 768 /************************************************************************** 769 * Controller 770 **************************************************************************/ 771 772 static struct genl_family genl_ctrl; 773 774 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 775 u32 flags, struct sk_buff *skb, u8 cmd) 776 { 777 void *hdr; 778 779 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 780 if (hdr == NULL) 781 return -1; 782 783 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 784 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || 785 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || 786 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || 787 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) 788 goto nla_put_failure; 789 790 if (family->n_ops) { 791 struct nlattr *nla_ops; 792 int i; 793 794 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS); 795 if (nla_ops == NULL) 796 goto nla_put_failure; 797 798 for (i = 0; i < family->n_ops; i++) { 799 struct nlattr *nest; 800 const struct genl_ops *ops = &family->ops[i]; 801 u32 op_flags = ops->flags; 802 803 if (ops->dumpit) 804 op_flags |= GENL_CMD_CAP_DUMP; 805 if (ops->doit) 806 op_flags |= GENL_CMD_CAP_DO; 807 if (family->policy) 808 op_flags |= GENL_CMD_CAP_HASPOL; 809 810 nest = nla_nest_start_noflag(skb, i + 1); 811 if (nest == NULL) 812 goto nla_put_failure; 813 814 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || 815 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) 816 goto nla_put_failure; 817 818 nla_nest_end(skb, nest); 819 } 820 821 nla_nest_end(skb, nla_ops); 822 } 823 824 if (family->n_mcgrps) { 825 struct nlattr *nla_grps; 826 int i; 827 828 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 829 if (nla_grps == NULL) 830 goto nla_put_failure; 831 832 for (i = 0; i < family->n_mcgrps; i++) { 833 struct nlattr *nest; 834 const struct genl_multicast_group *grp; 835 836 grp = &family->mcgrps[i]; 837 838 nest = nla_nest_start_noflag(skb, i + 1); 839 if (nest == NULL) 840 goto nla_put_failure; 841 842 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, 843 family->mcgrp_offset + i) || 844 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 845 grp->name)) 846 goto nla_put_failure; 847 848 nla_nest_end(skb, nest); 849 } 850 nla_nest_end(skb, nla_grps); 851 } 852 853 genlmsg_end(skb, hdr); 854 return 0; 855 856 nla_put_failure: 857 genlmsg_cancel(skb, hdr); 858 return -EMSGSIZE; 859 } 860 861 static int ctrl_fill_mcgrp_info(const struct genl_family *family, 862 const struct genl_multicast_group *grp, 863 int grp_id, u32 portid, u32 seq, u32 flags, 864 struct sk_buff *skb, u8 cmd) 865 { 866 void *hdr; 867 struct nlattr *nla_grps; 868 struct nlattr *nest; 869 870 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); 871 if (hdr == NULL) 872 return -1; 873 874 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || 875 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) 876 goto nla_put_failure; 877 878 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS); 879 if (nla_grps == NULL) 880 goto nla_put_failure; 881 882 nest = nla_nest_start_noflag(skb, 1); 883 if (nest == NULL) 884 goto nla_put_failure; 885 886 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || 887 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, 888 grp->name)) 889 goto nla_put_failure; 890 891 nla_nest_end(skb, nest); 892 nla_nest_end(skb, nla_grps); 893 894 genlmsg_end(skb, hdr); 895 return 0; 896 897 nla_put_failure: 898 genlmsg_cancel(skb, hdr); 899 return -EMSGSIZE; 900 } 901 902 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 903 { 904 int n = 0; 905 struct genl_family *rt; 906 struct net *net = sock_net(skb->sk); 907 int fams_to_skip = cb->args[0]; 908 unsigned int id; 909 910 idr_for_each_entry(&genl_fam_idr, rt, id) { 911 if (!rt->netnsok && !net_eq(net, &init_net)) 912 continue; 913 914 if (n++ < fams_to_skip) 915 continue; 916 917 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, 918 cb->nlh->nlmsg_seq, NLM_F_MULTI, 919 skb, CTRL_CMD_NEWFAMILY) < 0) { 920 n--; 921 break; 922 } 923 } 924 925 cb->args[0] = n; 926 return skb->len; 927 } 928 929 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, 930 u32 portid, int seq, u8 cmd) 931 { 932 struct sk_buff *skb; 933 int err; 934 935 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 936 if (skb == NULL) 937 return ERR_PTR(-ENOBUFS); 938 939 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); 940 if (err < 0) { 941 nlmsg_free(skb); 942 return ERR_PTR(err); 943 } 944 945 return skb; 946 } 947 948 static struct sk_buff * 949 ctrl_build_mcgrp_msg(const struct genl_family *family, 950 const struct genl_multicast_group *grp, 951 int grp_id, u32 portid, int seq, u8 cmd) 952 { 953 struct sk_buff *skb; 954 int err; 955 956 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 957 if (skb == NULL) 958 return ERR_PTR(-ENOBUFS); 959 960 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, 961 seq, 0, skb, cmd); 962 if (err < 0) { 963 nlmsg_free(skb); 964 return ERR_PTR(err); 965 } 966 967 return skb; 968 } 969 970 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { 971 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, 972 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, 973 .len = GENL_NAMSIZ - 1 }, 974 }; 975 976 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) 977 { 978 struct sk_buff *msg; 979 const struct genl_family *res = NULL; 980 int err = -EINVAL; 981 982 if (info->attrs[CTRL_ATTR_FAMILY_ID]) { 983 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); 984 res = genl_family_find_byid(id); 985 err = -ENOENT; 986 } 987 988 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { 989 char *name; 990 991 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); 992 res = genl_family_find_byname(name); 993 #ifdef CONFIG_MODULES 994 if (res == NULL) { 995 genl_unlock(); 996 up_read(&cb_lock); 997 request_module("net-pf-%d-proto-%d-family-%s", 998 PF_NETLINK, NETLINK_GENERIC, name); 999 down_read(&cb_lock); 1000 genl_lock(); 1001 res = genl_family_find_byname(name); 1002 } 1003 #endif 1004 err = -ENOENT; 1005 } 1006 1007 if (res == NULL) 1008 return err; 1009 1010 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { 1011 /* family doesn't exist here */ 1012 return -ENOENT; 1013 } 1014 1015 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, 1016 CTRL_CMD_NEWFAMILY); 1017 if (IS_ERR(msg)) 1018 return PTR_ERR(msg); 1019 1020 return genlmsg_reply(msg, info); 1021 } 1022 1023 static int genl_ctrl_event(int event, const struct genl_family *family, 1024 const struct genl_multicast_group *grp, 1025 int grp_id) 1026 { 1027 struct sk_buff *msg; 1028 1029 /* genl is still initialising */ 1030 if (!init_net.genl_sock) 1031 return 0; 1032 1033 switch (event) { 1034 case CTRL_CMD_NEWFAMILY: 1035 case CTRL_CMD_DELFAMILY: 1036 WARN_ON(grp); 1037 msg = ctrl_build_family_msg(family, 0, 0, event); 1038 break; 1039 case CTRL_CMD_NEWMCAST_GRP: 1040 case CTRL_CMD_DELMCAST_GRP: 1041 BUG_ON(!grp); 1042 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); 1043 break; 1044 default: 1045 return -EINVAL; 1046 } 1047 1048 if (IS_ERR(msg)) 1049 return PTR_ERR(msg); 1050 1051 if (!family->netnsok) { 1052 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, 1053 0, GFP_KERNEL); 1054 } else { 1055 rcu_read_lock(); 1056 genlmsg_multicast_allns(&genl_ctrl, msg, 0, 1057 0, GFP_ATOMIC); 1058 rcu_read_unlock(); 1059 } 1060 1061 return 0; 1062 } 1063 1064 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) 1065 { 1066 const struct genl_family *rt; 1067 unsigned int fam_id = cb->args[0]; 1068 int err; 1069 1070 if (!fam_id) { 1071 struct nlattr *tb[CTRL_ATTR_MAX + 1]; 1072 1073 err = genlmsg_parse(cb->nlh, &genl_ctrl, tb, 1074 genl_ctrl.maxattr, 1075 genl_ctrl.policy, cb->extack); 1076 if (err) 1077 return err; 1078 1079 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME]) 1080 return -EINVAL; 1081 1082 if (tb[CTRL_ATTR_FAMILY_ID]) { 1083 fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); 1084 } else { 1085 rt = genl_family_find_byname( 1086 nla_data(tb[CTRL_ATTR_FAMILY_NAME])); 1087 if (!rt) 1088 return -ENOENT; 1089 fam_id = rt->id; 1090 } 1091 } 1092 1093 rt = genl_family_find_byid(fam_id); 1094 if (!rt) 1095 return -ENOENT; 1096 1097 if (!rt->policy) 1098 return -ENODATA; 1099 1100 err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]); 1101 if (err) 1102 return err; 1103 1104 while (netlink_policy_dump_loop(&cb->args[1])) { 1105 void *hdr; 1106 struct nlattr *nest; 1107 1108 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, 1109 cb->nlh->nlmsg_seq, &genl_ctrl, 1110 NLM_F_MULTI, CTRL_CMD_GETPOLICY); 1111 if (!hdr) 1112 goto nla_put_failure; 1113 1114 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id)) 1115 goto nla_put_failure; 1116 1117 nest = nla_nest_start(skb, CTRL_ATTR_POLICY); 1118 if (!nest) 1119 goto nla_put_failure; 1120 1121 if (netlink_policy_dump_write(skb, cb->args[1])) 1122 goto nla_put_failure; 1123 1124 nla_nest_end(skb, nest); 1125 1126 genlmsg_end(skb, hdr); 1127 continue; 1128 1129 nla_put_failure: 1130 genlmsg_cancel(skb, hdr); 1131 break; 1132 } 1133 1134 cb->args[0] = fam_id; 1135 return skb->len; 1136 } 1137 1138 static const struct genl_ops genl_ctrl_ops[] = { 1139 { 1140 .cmd = CTRL_CMD_GETFAMILY, 1141 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1142 .doit = ctrl_getfamily, 1143 .dumpit = ctrl_dumpfamily, 1144 }, 1145 { 1146 .cmd = CTRL_CMD_GETPOLICY, 1147 .dumpit = ctrl_dumppolicy, 1148 }, 1149 }; 1150 1151 static const struct genl_multicast_group genl_ctrl_groups[] = { 1152 { .name = "notify", }, 1153 }; 1154 1155 static struct genl_family genl_ctrl __ro_after_init = { 1156 .module = THIS_MODULE, 1157 .ops = genl_ctrl_ops, 1158 .n_ops = ARRAY_SIZE(genl_ctrl_ops), 1159 .mcgrps = genl_ctrl_groups, 1160 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), 1161 .id = GENL_ID_CTRL, 1162 .name = "nlctrl", 1163 .version = 0x2, 1164 .maxattr = CTRL_ATTR_MAX, 1165 .policy = ctrl_policy, 1166 .netnsok = true, 1167 }; 1168 1169 static int genl_bind(struct net *net, int group) 1170 { 1171 struct genl_family *f; 1172 int err = -ENOENT; 1173 unsigned int id; 1174 1175 down_read(&cb_lock); 1176 1177 idr_for_each_entry(&genl_fam_idr, f, id) { 1178 if (group >= f->mcgrp_offset && 1179 group < f->mcgrp_offset + f->n_mcgrps) { 1180 int fam_grp = group - f->mcgrp_offset; 1181 1182 if (!f->netnsok && net != &init_net) 1183 err = -ENOENT; 1184 else if (f->mcast_bind) 1185 err = f->mcast_bind(net, fam_grp); 1186 else 1187 err = 0; 1188 break; 1189 } 1190 } 1191 up_read(&cb_lock); 1192 1193 return err; 1194 } 1195 1196 static void genl_unbind(struct net *net, int group) 1197 { 1198 struct genl_family *f; 1199 unsigned int id; 1200 1201 down_read(&cb_lock); 1202 1203 idr_for_each_entry(&genl_fam_idr, f, id) { 1204 if (group >= f->mcgrp_offset && 1205 group < f->mcgrp_offset + f->n_mcgrps) { 1206 int fam_grp = group - f->mcgrp_offset; 1207 1208 if (f->mcast_unbind) 1209 f->mcast_unbind(net, fam_grp); 1210 break; 1211 } 1212 } 1213 up_read(&cb_lock); 1214 } 1215 1216 static int __net_init genl_pernet_init(struct net *net) 1217 { 1218 struct netlink_kernel_cfg cfg = { 1219 .input = genl_rcv, 1220 .flags = NL_CFG_F_NONROOT_RECV, 1221 .bind = genl_bind, 1222 .unbind = genl_unbind, 1223 }; 1224 1225 /* we'll bump the group number right afterwards */ 1226 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); 1227 1228 if (!net->genl_sock && net_eq(net, &init_net)) 1229 panic("GENL: Cannot initialize generic netlink\n"); 1230 1231 if (!net->genl_sock) 1232 return -ENOMEM; 1233 1234 return 0; 1235 } 1236 1237 static void __net_exit genl_pernet_exit(struct net *net) 1238 { 1239 netlink_kernel_release(net->genl_sock); 1240 net->genl_sock = NULL; 1241 } 1242 1243 static struct pernet_operations genl_pernet_ops = { 1244 .init = genl_pernet_init, 1245 .exit = genl_pernet_exit, 1246 }; 1247 1248 static int __init genl_init(void) 1249 { 1250 int err; 1251 1252 err = genl_register_family(&genl_ctrl); 1253 if (err < 0) 1254 goto problem; 1255 1256 err = register_pernet_subsys(&genl_pernet_ops); 1257 if (err) 1258 goto problem; 1259 1260 return 0; 1261 1262 problem: 1263 panic("GENL: Cannot register controller: %d\n", err); 1264 } 1265 1266 subsys_initcall(genl_init); 1267 1268 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, 1269 gfp_t flags) 1270 { 1271 struct sk_buff *tmp; 1272 struct net *net, *prev = NULL; 1273 bool delivered = false; 1274 int err; 1275 1276 for_each_net_rcu(net) { 1277 if (prev) { 1278 tmp = skb_clone(skb, flags); 1279 if (!tmp) { 1280 err = -ENOMEM; 1281 goto error; 1282 } 1283 err = nlmsg_multicast(prev->genl_sock, tmp, 1284 portid, group, flags); 1285 if (!err) 1286 delivered = true; 1287 else if (err != -ESRCH) 1288 goto error; 1289 } 1290 1291 prev = net; 1292 } 1293 1294 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); 1295 if (!err) 1296 delivered = true; 1297 else if (err != -ESRCH) 1298 return err; 1299 return delivered ? 0 : -ESRCH; 1300 error: 1301 kfree_skb(skb); 1302 return err; 1303 } 1304 1305 int genlmsg_multicast_allns(const struct genl_family *family, 1306 struct sk_buff *skb, u32 portid, 1307 unsigned int group, gfp_t flags) 1308 { 1309 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1310 return -EINVAL; 1311 group = family->mcgrp_offset + group; 1312 return genlmsg_mcast(skb, portid, group, flags); 1313 } 1314 EXPORT_SYMBOL(genlmsg_multicast_allns); 1315 1316 void genl_notify(const struct genl_family *family, struct sk_buff *skb, 1317 struct genl_info *info, u32 group, gfp_t flags) 1318 { 1319 struct net *net = genl_info_net(info); 1320 struct sock *sk = net->genl_sock; 1321 int report = 0; 1322 1323 if (info->nlhdr) 1324 report = nlmsg_report(info->nlhdr); 1325 1326 if (WARN_ON_ONCE(group >= family->n_mcgrps)) 1327 return; 1328 group = family->mcgrp_offset + group; 1329 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); 1330 } 1331 EXPORT_SYMBOL(genl_notify); 1332