net/netlink/genetlink.c

   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 int genl_get_cmd_cnt(const struct genl_family *family)
 111 {
 112         return family->n_ops + family->n_small_ops;
 113 }
 114
 115 static void genl_op_from_full(const struct genl_family *family,
 116                               unsigned int i, struct genl_ops *op)
 117 {
 118         *op = family->ops[i];
 119
 120         if (!op->maxattr)
 121                 op->maxattr = family->maxattr;
 122         if (!op->policy)
 123                 op->policy = family->policy;
 124 }
 125
 126 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
 127                              struct genl_ops *op)
 128 {
 129         int i;
 130
 131         for (i = 0; i < family->n_ops; i++)
 132                 if (family->ops[i].cmd == cmd) {
 133                         genl_op_from_full(family, i, op);
 134                         return 0;
 135                 }
 136
 137         return -ENOENT;
 138 }
 139
 140 static void genl_op_from_small(const struct genl_family *family,
 141                                unsigned int i, struct genl_ops *op)
 142 {
 143         memset(op, 0, sizeof(*op));
 144         op->doit        = family->small_ops[i].doit;
 145         op->dumpit      = family->small_ops[i].dumpit;
 146         op->cmd         = family->small_ops[i].cmd;
 147         op->internal_flags = family->small_ops[i].internal_flags;
 148         op->flags       = family->small_ops[i].flags;
 149         op->validate    = family->small_ops[i].validate;
 150
 151         op->maxattr = family->maxattr;
 152         op->policy = family->policy;
 153 }
 154
 155 static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
 156                               struct genl_ops *op)
 157 {
 158         int i;
 159
 160         for (i = 0; i < family->n_small_ops; i++)
 161                 if (family->small_ops[i].cmd == cmd) {
 162                         genl_op_from_small(family, i, op);
 163                         return 0;
 164                 }
 165
 166         return -ENOENT;
 167 }
 168
 169 static int genl_get_cmd(u32 cmd, const struct genl_family *family,
 170                         struct genl_ops *op)
 171 {
 172         if (!genl_get_cmd_full(cmd, family, op))
 173                 return 0;
 174         return genl_get_cmd_small(cmd, family, op);
 175 }
 176
 177 static void genl_get_cmd_by_index(unsigned int i,
 178                                   const struct genl_family *family,
 179                                   struct genl_ops *op)
 180 {
 181         if (i < family->n_ops)
 182                 genl_op_from_full(family, i, op);
 183         else if (i < family->n_ops + family->n_small_ops)
 184                 genl_op_from_small(family, i - family->n_ops, op);
 185         else
 186                 WARN_ON_ONCE(1);
 187 }
 188
 189 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 190 {
 191         unsigned long *new_groups;
 192         int start = 0;
 193         int i;
 194         int id;
 195         bool fits;
 196
 197         do {
 198                 if (start == 0)
 199                         id = find_first_zero_bit(mc_groups,
 200                                                  mc_groups_longs *
 201                                                  BITS_PER_LONG);
 202                 else
 203                         id = find_next_zero_bit(mc_groups,
 204                                                 mc_groups_longs * BITS_PER_LONG,
 205                                                 start);
 206
 207                 fits = true;
 208                 for (i = id;
 209                      i < min_t(int, id + n_groups,
 210                                mc_groups_longs * BITS_PER_LONG);
 211                      i++) {
 212                         if (test_bit(i, mc_groups)) {
 213                                 start = i;
 214                                 fits = false;
 215                                 break;
 216                         }
 217                 }
 218
 219                 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
 220                         unsigned long new_longs = mc_groups_longs +
 221                                                   BITS_TO_LONGS(n_groups);
 222                         size_t nlen = new_longs * sizeof(unsigned long);
 223
 224                         if (mc_groups == &mc_group_start) {
 225                                 new_groups = kzalloc(nlen, GFP_KERNEL);
 226                                 if (!new_groups)
 227                                         return -ENOMEM;
 228                                 mc_groups = new_groups;
 229                                 *mc_groups = mc_group_start;
 230                         } else {
 231                                 new_groups = krealloc(mc_groups, nlen,
 232                                                       GFP_KERNEL);
 233                                 if (!new_groups)
 234                                         return -ENOMEM;
 235                                 mc_groups = new_groups;
 236                                 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
 237                                         mc_groups[mc_groups_longs + i] = 0;
 238                         }
 239                         mc_groups_longs = new_longs;
 240                 }
 241         } while (!fits);
 242
 243         for (i = id; i < id + n_groups; i++)
 244                 set_bit(i, mc_groups);
 245         *first_id = id;
 246         return 0;
 247 }
 248
 249 static struct genl_family genl_ctrl;
 250
 251 static int genl_validate_assign_mc_groups(struct genl_family *family)
 252 {
 253         int first_id;
 254         int n_groups = family->n_mcgrps;
 255         int err = 0, i;
 256         bool groups_allocated = false;
 257
 258         if (!n_groups)
 259                 return 0;
 260
 261         for (i = 0; i < n_groups; i++) {
 262                 const struct genl_multicast_group *grp = &family->mcgrps[i];
 263
 264                 if (WARN_ON(grp->name[0] == '\0'))
 265                         return -EINVAL;
 266                 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
 267                         return -EINVAL;
 268         }
 269
 270         /* special-case our own group and hacks */
 271         if (family == &genl_ctrl) {
 272                 first_id = GENL_ID_CTRL;
 273                 BUG_ON(n_groups != 1);
 274         } else if (strcmp(family->name, "NET_DM") == 0) {
 275                 first_id = 1;
 276                 BUG_ON(n_groups != 1);
 277         } else if (family->id == GENL_ID_VFS_DQUOT) {
 278                 first_id = GENL_ID_VFS_DQUOT;
 279                 BUG_ON(n_groups != 1);
 280         } else if (family->id == GENL_ID_PMCRAID) {
 281                 first_id = GENL_ID_PMCRAID;
 282                 BUG_ON(n_groups != 1);
 283         } else {
 284                 groups_allocated = true;
 285                 err = genl_allocate_reserve_groups(n_groups, &first_id);
 286                 if (err)
 287                         return err;
 288         }
 289
 290         family->mcgrp_offset = first_id;
 291
 292         /* if still initializing, can't and don't need to realloc bitmaps */
 293         if (!init_net.genl_sock)
 294                 return 0;
 295
 296         if (family->netnsok) {
 297                 struct net *net;
 298
 299                 netlink_table_grab();
 300                 rcu_read_lock();
 301                 for_each_net_rcu(net) {
 302                         err = __netlink_change_ngroups(net->genl_sock,
 303                                         mc_groups_longs * BITS_PER_LONG);
 304                         if (err) {
 305                                 /*
 306                                  * No need to roll back, can only fail if
 307                                  * memory allocation fails and then the
 308                                  * number of _possible_ groups has been
 309                                  * increased on some sockets which is ok.
 310                                  */
 311                                 break;
 312                         }
 313                 }
 314                 rcu_read_unlock();
 315                 netlink_table_ungrab();
 316         } else {
 317                 err = netlink_change_ngroups(init_net.genl_sock,
 318                                              mc_groups_longs * BITS_PER_LONG);
 319         }
 320
 321         if (groups_allocated && err) {
 322                 for (i = 0; i < family->n_mcgrps; i++)
 323                         clear_bit(family->mcgrp_offset + i, mc_groups);
 324         }
 325
 326         return err;
 327 }
 328
 329 static void genl_unregister_mc_groups(const struct genl_family *family)
 330 {
 331         struct net *net;
 332         int i;
 333
 334         netlink_table_grab();
 335         rcu_read_lock();
 336         for_each_net_rcu(net) {
 337                 for (i = 0; i < family->n_mcgrps; i++)
 338                         __netlink_clear_multicast_users(
 339                                 net->genl_sock, family->mcgrp_offset + i);
 340         }
 341         rcu_read_unlock();
 342         netlink_table_ungrab();
 343
 344         for (i = 0; i < family->n_mcgrps; i++) {
 345                 int grp_id = family->mcgrp_offset + i;
 346
 347                 if (grp_id != 1)
 348                         clear_bit(grp_id, mc_groups);
 349                 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
 350                                 &family->mcgrps[i], grp_id);
 351         }
 352 }
 353
 354 static int genl_validate_ops(const struct genl_family *family)
 355 {
 356         int i, j;
 357
 358         if (WARN_ON(family->n_ops && !family->ops) ||
 359             WARN_ON(family->n_small_ops && !family->small_ops))
 360                 return -EINVAL;
 361
 362         for (i = 0; i < genl_get_cmd_cnt(family); i++) {
 363                 struct genl_ops op;
 364
 365                 genl_get_cmd_by_index(i, family, &op);
 366                 if (op.dumpit == NULL && op.doit == NULL)
 367                         return -EINVAL;
 368                 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
 369                         struct genl_ops op2;
 370
 371                         genl_get_cmd_by_index(j, family, &op2);
 372                         if (op.cmd == op2.cmd)
 373                                 return -EINVAL;
 374                 }
 375         }
 376
 377         return 0;
 378 }
 379
 380 /**
 381  * genl_register_family - register a generic netlink family
 382  * @family: generic netlink family
 383  *
 384  * Registers the specified family after validating it first. Only one
 385  * family may be registered with the same family name or identifier.
 386  *
 387  * The family's ops, multicast groups and module pointer must already
 388  * be assigned.
 389  *
 390  * Return 0 on success or a negative error code.
 391  */
 392 int genl_register_family(struct genl_family *family)
 393 {
 394         int err, i;
 395         int start = GENL_START_ALLOC, end = GENL_MAX_ID;
 396
 397         err = genl_validate_ops(family);
 398         if (err)
 399                 return err;
 400
 401         genl_lock_all();
 402
 403         if (genl_family_find_byname(family->name)) {
 404                 err = -EEXIST;
 405                 goto errout_locked;
 406         }
 407
 408         /*
 409          * Sadly, a few cases need to be special-cased
 410          * due to them having previously abused the API
 411          * and having used their family ID also as their
 412          * multicast group ID, so we use reserved IDs
 413          * for both to be sure we can do that mapping.
 414          */
 415         if (family == &genl_ctrl) {
 416                 /* and this needs to be special for initial family lookups */
 417                 start = end = GENL_ID_CTRL;
 418         } else if (strcmp(family->name, "pmcraid") == 0) {
 419                 start = end = GENL_ID_PMCRAID;
 420         } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
 421                 start = end = GENL_ID_VFS_DQUOT;
 422         }
 423
 424         family->id = idr_alloc_cyclic(&genl_fam_idr, family,
 425                                       start, end + 1, GFP_KERNEL);
 426         if (family->id < 0) {
 427                 err = family->id;
 428                 goto errout_locked;
 429         }
 430
 431         err = genl_validate_assign_mc_groups(family);
 432         if (err)
 433                 goto errout_remove;
 434
 435         genl_unlock_all();
 436
 437         /* send all events */
 438         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
 439         for (i = 0; i < family->n_mcgrps; i++)
 440                 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
 441                                 &family->mcgrps[i], family->mcgrp_offset + i);
 442
 443         return 0;
 444
 445 errout_remove:
 446         idr_remove(&genl_fam_idr, family->id);
 447 errout_locked:
 448         genl_unlock_all();
 449         return err;
 450 }
 451 EXPORT_SYMBOL(genl_register_family);
 452
 453 /**
 454  * genl_unregister_family - unregister generic netlink family
 455  * @family: generic netlink family
 456  *
 457  * Unregisters the specified family.
 458  *
 459  * Returns 0 on success or a negative error code.
 460  */
 461 int genl_unregister_family(const struct genl_family *family)
 462 {
 463         genl_lock_all();
 464
 465         if (!genl_family_find_byid(family->id)) {
 466                 genl_unlock_all();
 467                 return -ENOENT;
 468         }
 469
 470         genl_unregister_mc_groups(family);
 471
 472         idr_remove(&genl_fam_idr, family->id);
 473
 474         up_write(&cb_lock);
 475         wait_event(genl_sk_destructing_waitq,
 476                    atomic_read(&genl_sk_destructing_cnt) == 0);
 477         genl_unlock();
 478
 479         genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 480
 481         return 0;
 482 }
 483 EXPORT_SYMBOL(genl_unregister_family);
 484
 485 /**
 486  * genlmsg_put - Add generic netlink header to netlink message
 487  * @skb: socket buffer holding the message
 488  * @portid: netlink portid the message is addressed to
 489  * @seq: sequence number (usually the one of the sender)
 490  * @family: generic netlink family
 491  * @flags: netlink message flags
 492  * @cmd: generic netlink command
 493  *
 494  * Returns pointer to user specific header
 495  */
 496 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 497                   const struct genl_family *family, int flags, u8 cmd)
 498 {
 499         struct nlmsghdr *nlh;
 500         struct genlmsghdr *hdr;
 501
 502         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 503                         family->hdrsize, flags);
 504         if (nlh == NULL)
 505                 return NULL;
 506
 507         hdr = nlmsg_data(nlh);
 508         hdr->cmd = cmd;
 509         hdr->version = family->version;
 510         hdr->reserved = 0;
 511
 512         return (char *) hdr + GENL_HDRLEN;
 513 }
 514 EXPORT_SYMBOL(genlmsg_put);
 515
 516 static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
 517 {
 518         return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
 519 }
 520
 521 static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
 522 {
 523         kfree(info);
 524 }
 525
 526 static struct nlattr **
 527 genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
 528                                 struct nlmsghdr *nlh,
 529                                 struct netlink_ext_ack *extack,
 530                                 const struct genl_ops *ops,
 531                                 int hdrlen,
 532                                 enum genl_validate_flags no_strict_flag)
 533 {
 534         enum netlink_validation validate = ops->validate & no_strict_flag ?
 535                                            NL_VALIDATE_LIBERAL :
 536                                            NL_VALIDATE_STRICT;
 537         struct nlattr **attrbuf;
 538         int err;
 539
 540         if (!ops->maxattr)
 541                 return NULL;
 542
 543         attrbuf = kmalloc_array(ops->maxattr + 1,
 544                                 sizeof(struct nlattr *), GFP_KERNEL);
 545         if (!attrbuf)
 546                 return ERR_PTR(-ENOMEM);
 547
 548         err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
 549                             validate, extack);
 550         if (err) {
 551                 kfree(attrbuf);
 552                 return ERR_PTR(err);
 553         }
 554         return attrbuf;
 555 }
 556
 557 static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
 558 {
 559         kfree(attrbuf);
 560 }
 561
 562 struct genl_start_context {
 563         const struct genl_family *family;
 564         struct nlmsghdr *nlh;
 565         struct netlink_ext_ack *extack;
 566         const struct genl_ops *ops;
 567         int hdrlen;
 568 };
 569
 570 static int genl_start(struct netlink_callback *cb)
 571 {
 572         struct genl_start_context *ctx = cb->data;
 573         const struct genl_ops *ops = ctx->ops;
 574         struct genl_dumpit_info *info;
 575         struct nlattr **attrs = NULL;
 576         int rc = 0;
 577
 578         if (ops->validate & GENL_DONT_VALIDATE_DUMP)
 579                 goto no_attrs;
 580
 581         if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
 582                 return -EINVAL;
 583
 584         attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
 585                                                 ops, ctx->hdrlen,
 586                                                 GENL_DONT_VALIDATE_DUMP_STRICT);
 587         if (IS_ERR(attrs))
 588                 return PTR_ERR(attrs);
 589
 590 no_attrs:
 591         info = genl_dumpit_info_alloc();
 592         if (!info) {
 593                 genl_family_rcv_msg_attrs_free(attrs);
 594                 return -ENOMEM;
 595         }
 596         info->family = ctx->family;
 597         info->op = *ops;
 598         info->attrs = attrs;
 599
 600         cb->data = info;
 601         if (ops->start) {
 602                 if (!ctx->family->parallel_ops)
 603                         genl_lock();
 604                 rc = ops->start(cb);
 605                 if (!ctx->family->parallel_ops)
 606                         genl_unlock();
 607         }
 608
 609         if (rc) {
 610                 genl_family_rcv_msg_attrs_free(info->attrs);
 611                 genl_dumpit_info_free(info);
 612                 cb->data = NULL;
 613         }
 614         return rc;
 615 }
 616
 617 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 618 {
 619         const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
 620         int rc;
 621
 622         genl_lock();
 623         rc = ops->dumpit(skb, cb);
 624         genl_unlock();
 625         return rc;
 626 }
 627
 628 static int genl_lock_done(struct netlink_callback *cb)
 629 {
 630         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 631         const struct genl_ops *ops = &info->op;
 632         int rc = 0;
 633
 634         if (ops->done) {
 635                 genl_lock();
 636                 rc = ops->done(cb);
 637                 genl_unlock();
 638         }
 639         genl_family_rcv_msg_attrs_free(info->attrs);
 640         genl_dumpit_info_free(info);
 641         return rc;
 642 }
 643
 644 static int genl_parallel_done(struct netlink_callback *cb)
 645 {
 646         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 647         const struct genl_ops *ops = &info->op;
 648         int rc = 0;
 649
 650         if (ops->done)
 651                 rc = ops->done(cb);
 652         genl_family_rcv_msg_attrs_free(info->attrs);
 653         genl_dumpit_info_free(info);
 654         return rc;
 655 }
 656
 657 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
 658                                       struct sk_buff *skb,
 659                                       struct nlmsghdr *nlh,
 660                                       struct netlink_ext_ack *extack,
 661                                       const struct genl_ops *ops,
 662                                       int hdrlen, struct net *net)
 663 {
 664         struct genl_start_context ctx;
 665         int err;
 666
 667         if (!ops->dumpit)
 668                 return -EOPNOTSUPP;
 669
 670         ctx.family = family;
 671         ctx.nlh = nlh;
 672         ctx.extack = extack;
 673         ctx.ops = ops;
 674         ctx.hdrlen = hdrlen;
 675
 676         if (!family->parallel_ops) {
 677                 struct netlink_dump_control c = {
 678                         .module = family->module,
 679                         .data = &ctx,
 680                         .start = genl_start,
 681                         .dump = genl_lock_dumpit,
 682                         .done = genl_lock_done,
 683                 };
 684
 685                 genl_unlock();
 686                 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 687                 genl_lock();
 688         } else {
 689                 struct netlink_dump_control c = {
 690                         .module = family->module,
 691                         .data = &ctx,
 692                         .start = genl_start,
 693                         .dump = ops->dumpit,
 694                         .done = genl_parallel_done,
 695                 };
 696
 697                 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 698         }
 699
 700         return err;
 701 }
 702
 703 static int genl_family_rcv_msg_doit(const struct genl_family *family,
 704                                     struct sk_buff *skb,
 705                                     struct nlmsghdr *nlh,
 706                                     struct netlink_ext_ack *extack,
 707                                     const struct genl_ops *ops,
 708                                     int hdrlen, struct net *net)
 709 {
 710         struct nlattr **attrbuf;
 711         struct genl_info info;
 712         int err;
 713
 714         if (!ops->doit)
 715                 return -EOPNOTSUPP;
 716
 717         attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
 718                                                   ops, hdrlen,
 719                                                   GENL_DONT_VALIDATE_STRICT);
 720         if (IS_ERR(attrbuf))
 721                 return PTR_ERR(attrbuf);
 722
 723         info.snd_seq = nlh->nlmsg_seq;
 724         info.snd_portid = NETLINK_CB(skb).portid;
 725         info.nlhdr = nlh;
 726         info.genlhdr = nlmsg_data(nlh);
 727         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 728         info.attrs = attrbuf;
 729         info.extack = extack;
 730         genl_info_net_set(&info, net);
 731         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 732
 733         if (family->pre_doit) {
 734                 err = family->pre_doit(ops, skb, &info);
 735                 if (err)
 736                         goto out;
 737         }
 738
 739         err = ops->doit(skb, &info);
 740
 741         if (family->post_doit)
 742                 family->post_doit(ops, skb, &info);
 743
 744 out:
 745         genl_family_rcv_msg_attrs_free(attrbuf);
 746
 747         return err;
 748 }
 749
 750 static int genl_family_rcv_msg(const struct genl_family *family,
 751                                struct sk_buff *skb,
 752                                struct nlmsghdr *nlh,
 753                                struct netlink_ext_ack *extack)
 754 {
 755         struct net *net = sock_net(skb->sk);
 756         struct genlmsghdr *hdr = nlmsg_data(nlh);
 757         struct genl_ops op;
 758         int hdrlen;
 759
 760         /* this family doesn't exist in this netns */
 761         if (!family->netnsok && !net_eq(net, &init_net))
 762                 return -ENOENT;
 763
 764         hdrlen = GENL_HDRLEN + family->hdrsize;
 765         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 766                 return -EINVAL;
 767
 768         if (genl_get_cmd(hdr->cmd, family, &op))
 769                 return -EOPNOTSUPP;
 770
 771         if ((op.flags & GENL_ADMIN_PERM) &&
 772             !netlink_capable(skb, CAP_NET_ADMIN))
 773                 return -EPERM;
 774
 775         if ((op.flags & GENL_UNS_ADMIN_PERM) &&
 776             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 777                 return -EPERM;
 778
 779         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
 780                 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
 781                                                   &op, hdrlen, net);
 782         else
 783                 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
 784                                                 &op, hdrlen, net);
 785 }
 786
 787 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 788                         struct netlink_ext_ack *extack)
 789 {
 790         const struct genl_family *family;
 791         int err;
 792
 793         family = genl_family_find_byid(nlh->nlmsg_type);
 794         if (family == NULL)
 795                 return -ENOENT;
 796
 797         if (!family->parallel_ops)
 798                 genl_lock();
 799
 800         err = genl_family_rcv_msg(family, skb, nlh, extack);
 801
 802         if (!family->parallel_ops)
 803                 genl_unlock();
 804
 805         return err;
 806 }
 807
 808 static void genl_rcv(struct sk_buff *skb)
 809 {
 810         down_read(&cb_lock);
 811         netlink_rcv_skb(skb, &genl_rcv_msg);
 812         up_read(&cb_lock);
 813 }
 814
 815 /**************************************************************************
 816  * Controller
 817  **************************************************************************/
 818
 819 static struct genl_family genl_ctrl;
 820
 821 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
 822                           u32 flags, struct sk_buff *skb, u8 cmd)
 823 {
 824         void *hdr;
 825
 826         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 827         if (hdr == NULL)
 828                 return -1;
 829
 830         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 831             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 832             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 833             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 834             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 835                 goto nla_put_failure;
 836
 837         if (genl_get_cmd_cnt(family)) {
 838                 struct nlattr *nla_ops;
 839                 int i;
 840
 841                 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
 842                 if (nla_ops == NULL)
 843                         goto nla_put_failure;
 844
 845                 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
 846                         struct nlattr *nest;
 847                         struct genl_ops op;
 848                         u32 op_flags;
 849
 850                         genl_get_cmd_by_index(i, family, &op);
 851                         op_flags = op.flags;
 852                         if (op.dumpit)
 853                                 op_flags |= GENL_CMD_CAP_DUMP;
 854                         if (op.doit)
 855                                 op_flags |= GENL_CMD_CAP_DO;
 856                         if (op.policy)
 857                                 op_flags |= GENL_CMD_CAP_HASPOL;
 858
 859                         nest = nla_nest_start_noflag(skb, i + 1);
 860                         if (nest == NULL)
 861                                 goto nla_put_failure;
 862
 863                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
 864                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 865                                 goto nla_put_failure;
 866
 867                         nla_nest_end(skb, nest);
 868                 }
 869
 870                 nla_nest_end(skb, nla_ops);
 871         }
 872
 873         if (family->n_mcgrps) {
 874                 struct nlattr *nla_grps;
 875                 int i;
 876
 877                 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
 878                 if (nla_grps == NULL)
 879                         goto nla_put_failure;
 880
 881                 for (i = 0; i < family->n_mcgrps; i++) {
 882                         struct nlattr *nest;
 883                         const struct genl_multicast_group *grp;
 884
 885                         grp = &family->mcgrps[i];
 886
 887                         nest = nla_nest_start_noflag(skb, i + 1);
 888                         if (nest == NULL)
 889                                 goto nla_put_failure;
 890
 891                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
 892                                         family->mcgrp_offset + i) ||
 893                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 894                                            grp->name))
 895                                 goto nla_put_failure;
 896
 897                         nla_nest_end(skb, nest);
 898                 }
 899                 nla_nest_end(skb, nla_grps);
 900         }
 901
 902         genlmsg_end(skb, hdr);
 903         return 0;
 904
 905 nla_put_failure:
 906         genlmsg_cancel(skb, hdr);
 907         return -EMSGSIZE;
 908 }
 909
 910 static int ctrl_fill_mcgrp_info(const struct genl_family *family,
 911                                 const struct genl_multicast_group *grp,
 912                                 int grp_id, u32 portid, u32 seq, u32 flags,
 913                                 struct sk_buff *skb, u8 cmd)
 914 {
 915         void *hdr;
 916         struct nlattr *nla_grps;
 917         struct nlattr *nest;
 918
 919         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 920         if (hdr == NULL)
 921                 return -1;
 922
 923         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 924             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 925                 goto nla_put_failure;
 926
 927         nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
 928         if (nla_grps == NULL)
 929                 goto nla_put_failure;
 930
 931         nest = nla_nest_start_noflag(skb, 1);
 932         if (nest == NULL)
 933                 goto nla_put_failure;
 934
 935         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
 936             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 937                            grp->name))
 938                 goto nla_put_failure;
 939
 940         nla_nest_end(skb, nest);
 941         nla_nest_end(skb, nla_grps);
 942
 943         genlmsg_end(skb, hdr);
 944         return 0;
 945
 946 nla_put_failure:
 947         genlmsg_cancel(skb, hdr);
 948         return -EMSGSIZE;
 949 }
 950
 951 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 952 {
 953         int n = 0;
 954         struct genl_family *rt;
 955         struct net *net = sock_net(skb->sk);
 956         int fams_to_skip = cb->args[0];
 957         unsigned int id;
 958
 959         idr_for_each_entry(&genl_fam_idr, rt, id) {
 960                 if (!rt->netnsok && !net_eq(net, &init_net))
 961                         continue;
 962
 963                 if (n++ < fams_to_skip)
 964                         continue;
 965
 966                 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 967                                    cb->nlh->nlmsg_seq, NLM_F_MULTI,
 968                                    skb, CTRL_CMD_NEWFAMILY) < 0) {
 969                         n--;
 970                         break;
 971                 }
 972         }
 973
 974         cb->args[0] = n;
 975         return skb->len;
 976 }
 977
 978 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
 979                                              u32 portid, int seq, u8 cmd)
 980 {
 981         struct sk_buff *skb;
 982         int err;
 983
 984         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 985         if (skb == NULL)
 986                 return ERR_PTR(-ENOBUFS);
 987
 988         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 989         if (err < 0) {
 990                 nlmsg_free(skb);
 991                 return ERR_PTR(err);
 992         }
 993
 994         return skb;
 995 }
 996
 997 static struct sk_buff *
 998 ctrl_build_mcgrp_msg(const struct genl_family *family,
 999                      const struct genl_multicast_group *grp,
1000                      int grp_id, u32 portid, int seq, u8 cmd)
1001 {
1002         struct sk_buff *skb;
1003         int err;
1004
1005         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1006         if (skb == NULL)
1007                 return ERR_PTR(-ENOBUFS);
1008
1009         err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1010                                    seq, 0, skb, cmd);
1011         if (err < 0) {
1012                 nlmsg_free(skb);
1013                 return ERR_PTR(err);
1014         }
1015
1016         return skb;
1017 }
1018
1019 static const struct nla_policy ctrl_policy_family[] = {
1020         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
1021         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1022                                     .len = GENL_NAMSIZ - 1 },
1023 };
1024
1025 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1026 {
1027         struct sk_buff *msg;
1028         const struct genl_family *res = NULL;
1029         int err = -EINVAL;
1030
1031         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1032                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1033                 res = genl_family_find_byid(id);
1034                 err = -ENOENT;
1035         }
1036
1037         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1038                 char *name;
1039
1040                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1041                 res = genl_family_find_byname(name);
1042 #ifdef CONFIG_MODULES
1043                 if (res == NULL) {
1044                         genl_unlock();
1045                         up_read(&cb_lock);
1046                         request_module("net-pf-%d-proto-%d-family-%s",
1047                                        PF_NETLINK, NETLINK_GENERIC, name);
1048                         down_read(&cb_lock);
1049                         genl_lock();
1050                         res = genl_family_find_byname(name);
1051                 }
1052 #endif
1053                 err = -ENOENT;
1054         }
1055
1056         if (res == NULL)
1057                 return err;
1058
1059         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1060                 /* family doesn't exist here */
1061                 return -ENOENT;
1062         }
1063
1064         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1065                                     CTRL_CMD_NEWFAMILY);
1066         if (IS_ERR(msg))
1067                 return PTR_ERR(msg);
1068
1069         return genlmsg_reply(msg, info);
1070 }
1071
1072 static int genl_ctrl_event(int event, const struct genl_family *family,
1073                            const struct genl_multicast_group *grp,
1074                            int grp_id)
1075 {
1076         struct sk_buff *msg;
1077
1078         /* genl is still initialising */
1079         if (!init_net.genl_sock)
1080                 return 0;
1081
1082         switch (event) {
1083         case CTRL_CMD_NEWFAMILY:
1084         case CTRL_CMD_DELFAMILY:
1085                 WARN_ON(grp);
1086                 msg = ctrl_build_family_msg(family, 0, 0, event);
1087                 break;
1088         case CTRL_CMD_NEWMCAST_GRP:
1089         case CTRL_CMD_DELMCAST_GRP:
1090                 BUG_ON(!grp);
1091                 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1092                 break;
1093         default:
1094                 return -EINVAL;
1095         }
1096
1097         if (IS_ERR(msg))
1098                 return PTR_ERR(msg);
1099
1100         if (!family->netnsok) {
1101                 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1102                                         0, GFP_KERNEL);
1103         } else {
1104                 rcu_read_lock();
1105                 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1106                                         0, GFP_ATOMIC);
1107                 rcu_read_unlock();
1108         }
1109
1110         return 0;
1111 }
1112
1113 struct ctrl_dump_policy_ctx {
1114         struct netlink_policy_dump_state *state;
1115         const struct genl_family *rt;
1116         unsigned int opidx;
1117         u32 op;
1118         u16 fam_id;
1119         u8 policies:1,
1120            single_op:1;
1121 };
1122
1123 static const struct nla_policy ctrl_policy_policy[] = {
1124         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
1125         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1126                                     .len = GENL_NAMSIZ - 1 },
1127         [CTRL_ATTR_OP]          = { .type = NLA_U32 },
1128 };
1129
1130 static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1131 {
1132         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1133         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1134         struct nlattr **tb = info->attrs;
1135         const struct genl_family *rt;
1136         struct genl_ops op;
1137         int err, i;
1138
1139         BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1140
1141         if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1142                 return -EINVAL;
1143
1144         if (tb[CTRL_ATTR_FAMILY_ID]) {
1145                 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1146         } else {
1147                 rt = genl_family_find_byname(
1148                         nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1149                 if (!rt)
1150                         return -ENOENT;
1151                 ctx->fam_id = rt->id;
1152         }
1153
1154         rt = genl_family_find_byid(ctx->fam_id);
1155         if (!rt)
1156                 return -ENOENT;
1157
1158         ctx->rt = rt;
1159
1160         if (tb[CTRL_ATTR_OP]) {
1161                 ctx->single_op = true;
1162                 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1163
1164                 err = genl_get_cmd(ctx->op, rt, &op);
1165                 if (err) {
1166                         NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1167                         return err;
1168                 }
1169
1170                 if (!op.policy)
1171                         return -ENODATA;
1172
1173                 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1174                                                       op.maxattr);
1175         }
1176
1177         for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1178                 genl_get_cmd_by_index(i, rt, &op);
1179
1180                 if (op.policy) {
1181                         err = netlink_policy_dump_add_policy(&ctx->state,
1182                                                              op.policy,
1183                                                              op.maxattr);
1184                         if (err)
1185                                 return err;
1186                 }
1187         }
1188
1189         if (!ctx->state)
1190                 return -ENODATA;
1191         return 0;
1192 }
1193
1194 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1195                                   struct netlink_callback *cb)
1196 {
1197         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1198         void *hdr;
1199
1200         hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1201                           cb->nlh->nlmsg_seq, &genl_ctrl,
1202                           NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1203         if (!hdr)
1204                 return NULL;
1205
1206         if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1207                 return NULL;
1208
1209         return hdr;
1210 }
1211
1212 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1213                                   struct netlink_callback *cb,
1214                                   struct genl_ops *op)
1215 {
1216         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1217         struct nlattr *nest_pol, *nest_op;
1218         void *hdr;
1219         int idx;
1220
1221         /* skip if we have nothing to show */
1222         if (!op->policy)
1223                 return 0;
1224         if (!op->doit &&
1225             (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1226                 return 0;
1227
1228         hdr = ctrl_dumppolicy_prep(skb, cb);
1229         if (!hdr)
1230                 return -ENOBUFS;
1231
1232         nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1233         if (!nest_pol)
1234                 goto err;
1235
1236         nest_op = nla_nest_start(skb, op->cmd);
1237         if (!nest_op)
1238                 goto err;
1239
1240         /* for now both do/dump are always the same */
1241         idx = netlink_policy_dump_get_policy_idx(ctx->state,
1242                                                  op->policy,
1243                                                  op->maxattr);
1244
1245         if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1246                 goto err;
1247
1248         if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1249             nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1250                 goto err;
1251
1252         nla_nest_end(skb, nest_op);
1253         nla_nest_end(skb, nest_pol);
1254         genlmsg_end(skb, hdr);
1255
1256         return 0;
1257 err:
1258         genlmsg_cancel(skb, hdr);
1259         return -ENOBUFS;
1260 }
1261
1262 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1263 {
1264         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1265         void *hdr;
1266
1267         if (!ctx->policies) {
1268                 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1269                         struct genl_ops op;
1270
1271                         if (ctx->single_op) {
1272                                 int err;
1273
1274                                 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1275                                 if (WARN_ON(err))
1276                                         return skb->len;
1277
1278                                 /* break out of the loop after this one */
1279                                 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1280                         } else {
1281                                 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1282                         }
1283
1284                         if (ctrl_dumppolicy_put_op(skb, cb, &op))
1285                                 return skb->len;
1286
1287                         ctx->opidx++;
1288                 }
1289
1290                 /* completed with the per-op policy index list */
1291                 ctx->policies = true;
1292         }
1293
1294         while (netlink_policy_dump_loop(ctx->state)) {
1295                 struct nlattr *nest;
1296
1297                 hdr = ctrl_dumppolicy_prep(skb, cb);
1298                 if (!hdr)
1299                         goto nla_put_failure;
1300
1301                 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1302                 if (!nest)
1303                         goto nla_put_failure;
1304
1305                 if (netlink_policy_dump_write(skb, ctx->state))
1306                         goto nla_put_failure;
1307
1308                 nla_nest_end(skb, nest);
1309
1310                 genlmsg_end(skb, hdr);
1311         }
1312
1313         return skb->len;
1314
1315 nla_put_failure:
1316         genlmsg_cancel(skb, hdr);
1317         return skb->len;
1318 }
1319
1320 static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1321 {
1322         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1323
1324         netlink_policy_dump_free(ctx->state);
1325         return 0;
1326 }
1327
1328 static const struct genl_ops genl_ctrl_ops[] = {
1329         {
1330                 .cmd            = CTRL_CMD_GETFAMILY,
1331                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1332                 .policy         = ctrl_policy_family,
1333                 .maxattr        = ARRAY_SIZE(ctrl_policy_family) - 1,
1334                 .doit           = ctrl_getfamily,
1335                 .dumpit         = ctrl_dumpfamily,
1336         },
1337         {
1338                 .cmd            = CTRL_CMD_GETPOLICY,
1339                 .policy         = ctrl_policy_policy,
1340                 .maxattr        = ARRAY_SIZE(ctrl_policy_policy) - 1,
1341                 .start          = ctrl_dumppolicy_start,
1342                 .dumpit         = ctrl_dumppolicy,
1343                 .done           = ctrl_dumppolicy_done,
1344         },
1345 };
1346
1347 static const struct genl_multicast_group genl_ctrl_groups[] = {
1348         { .name = "notify", },
1349 };
1350
1351 static struct genl_family genl_ctrl __ro_after_init = {
1352         .module = THIS_MODULE,
1353         .ops = genl_ctrl_ops,
1354         .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1355         .mcgrps = genl_ctrl_groups,
1356         .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1357         .id = GENL_ID_CTRL,
1358         .name = "nlctrl",
1359         .version = 0x2,
1360         .netnsok = true,
1361 };
1362
1363 static int genl_bind(struct net *net, int group)
1364 {
1365         const struct genl_family *family;
1366         unsigned int id;
1367         int ret = 0;
1368
1369         genl_lock_all();
1370
1371         idr_for_each_entry(&genl_fam_idr, family, id) {
1372                 const struct genl_multicast_group *grp;
1373                 int i;
1374
1375                 if (family->n_mcgrps == 0)
1376                         continue;
1377
1378                 i = group - family->mcgrp_offset;
1379                 if (i < 0 || i >= family->n_mcgrps)
1380                         continue;
1381
1382                 grp = &family->mcgrps[i];
1383                 if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
1384                     !ns_capable(net->user_ns, CAP_NET_ADMIN))
1385                         ret = -EPERM;
1386
1387                 break;
1388         }
1389
1390         genl_unlock_all();
1391         return ret;
1392 }
1393
1394 static int __net_init genl_pernet_init(struct net *net)
1395 {
1396         struct netlink_kernel_cfg cfg = {
1397                 .input          = genl_rcv,
1398                 .flags          = NL_CFG_F_NONROOT_RECV,
1399                 .bind           = genl_bind,
1400         };
1401
1402         /* we'll bump the group number right afterwards */
1403         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1404
1405         if (!net->genl_sock && net_eq(net, &init_net))
1406                 panic("GENL: Cannot initialize generic netlink\n");
1407
1408         if (!net->genl_sock)
1409                 return -ENOMEM;
1410
1411         return 0;
1412 }
1413
1414 static void __net_exit genl_pernet_exit(struct net *net)
1415 {
1416         netlink_kernel_release(net->genl_sock);
1417         net->genl_sock = NULL;
1418 }
1419
1420 static struct pernet_operations genl_pernet_ops = {
1421         .init = genl_pernet_init,
1422         .exit = genl_pernet_exit,
1423 };
1424
1425 static int __init genl_init(void)
1426 {
1427         int err;
1428
1429         err = genl_register_family(&genl_ctrl);
1430         if (err < 0)
1431                 goto problem;
1432
1433         err = register_pernet_subsys(&genl_pernet_ops);
1434         if (err)
1435                 goto problem;
1436
1437         return 0;
1438
1439 problem:
1440         panic("GENL: Cannot register controller: %d\n", err);
1441 }
1442
1443 core_initcall(genl_init);
1444
1445 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1446                          gfp_t flags)
1447 {
1448         struct sk_buff *tmp;
1449         struct net *net, *prev = NULL;
1450         bool delivered = false;
1451         int err;
1452
1453         for_each_net_rcu(net) {
1454                 if (prev) {
1455                         tmp = skb_clone(skb, flags);
1456                         if (!tmp) {
1457                                 err = -ENOMEM;
1458                                 goto error;
1459                         }
1460                         err = nlmsg_multicast(prev->genl_sock, tmp,
1461                                               portid, group, flags);
1462                         if (!err)
1463                                 delivered = true;
1464                         else if (err != -ESRCH)
1465                                 goto error;
1466                 }
1467
1468                 prev = net;
1469         }
1470
1471         err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1472         if (!err)
1473                 delivered = true;
1474         else if (err != -ESRCH)
1475                 return err;
1476         return delivered ? 0 : -ESRCH;
1477  error:
1478         kfree_skb(skb);
1479         return err;
1480 }
1481
1482 int genlmsg_multicast_allns(const struct genl_family *family,
1483                             struct sk_buff *skb, u32 portid,
1484                             unsigned int group, gfp_t flags)
1485 {
1486         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1487                 return -EINVAL;
1488         group = family->mcgrp_offset + group;
1489         return genlmsg_mcast(skb, portid, group, flags);
1490 }
1491 EXPORT_SYMBOL(genlmsg_multicast_allns);
1492
1493 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1494                  struct genl_info *info, u32 group, gfp_t flags)
1495 {
1496         struct net *net = genl_info_net(info);
1497         struct sock *sk = net->genl_sock;
1498         int report = 0;
1499
1500         if (info->nlhdr)
1501                 report = nlmsg_report(info->nlhdr);
1502
1503         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1504                 return;
1505         group = family->mcgrp_offset + group;
1506         nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1507 }
1508 EXPORT_SYMBOL(genl_notify);