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 static void genl_lock_all(void)
  44 {
  45         down_write(&cb_lock);
  46         genl_lock();
  47 }
  48
  49 static void genl_unlock_all(void)
  50 {
  51         genl_unlock();
  52         up_write(&cb_lock);
  53 }
  54
  55 static DEFINE_IDR(genl_fam_idr);
  56
  57 /*
  58  * Bitmap of multicast groups that are currently in use.
  59  *
  60  * To avoid an allocation at boot of just one unsigned long,
  61  * declare it global instead.
  62  * Bit 0 is marked as already used since group 0 is invalid.
  63  * Bit 1 is marked as already used since the drop-monitor code
  64  * abuses the API and thinks it can statically use group 1.
  65  * That group will typically conflict with other groups that
  66  * any proper users use.
  67  * Bit 16 is marked as used since it's used for generic netlink
  68  * and the code no longer marks pre-reserved IDs as used.
  69  * Bit 17 is marked as already used since the VFS quota code
  70  * also abused this API and relied on family == group ID, we
  71  * cater to that by giving it a static family and group ID.
  72  * Bit 18 is marked as already used since the PMCRAID driver
  73  * did the same thing as the VFS quota code (maybe copied?)
  74  */
  75 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
  76                                       BIT(GENL_ID_VFS_DQUOT) |
  77                                       BIT(GENL_ID_PMCRAID);
  78 static unsigned long *mc_groups = &mc_group_start;
  79 static unsigned long mc_groups_longs = 1;
  80
  81 static int genl_ctrl_event(int event, const struct genl_family *family,
  82                            const struct genl_multicast_group *grp,
  83                            int grp_id);
  84
  85 static const struct genl_family *genl_family_find_byid(unsigned int id)
  86 {
  87         return idr_find(&genl_fam_idr, id);
  88 }
  89
  90 static const struct genl_family *genl_family_find_byname(char *name)
  91 {
  92         const struct genl_family *family;
  93         unsigned int id;
  94
  95         idr_for_each_entry(&genl_fam_idr, family, id)
  96                 if (strcmp(family->name, name) == 0)
  97                         return family;
  98
  99         return NULL;
 100 }
 101
 102 static int genl_get_cmd_cnt(const struct genl_family *family)
 103 {
 104         return family->n_ops + family->n_small_ops;
 105 }
 106
 107 static void genl_op_from_full(const struct genl_family *family,
 108                               unsigned int i, struct genl_ops *op)
 109 {
 110         *op = family->ops[i];
 111
 112         if (!op->maxattr)
 113                 op->maxattr = family->maxattr;
 114         if (!op->policy)
 115                 op->policy = family->policy;
 116 }
 117
 118 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
 119                              struct genl_ops *op)
 120 {
 121         int i;
 122
 123         for (i = 0; i < family->n_ops; i++)
 124                 if (family->ops[i].cmd == cmd) {
 125                         genl_op_from_full(family, i, op);
 126                         return 0;
 127                 }
 128
 129         return -ENOENT;
 130 }
 131
 132 static void genl_op_from_small(const struct genl_family *family,
 133                                unsigned int i, struct genl_ops *op)
 134 {
 135         memset(op, 0, sizeof(*op));
 136         op->doit        = family->small_ops[i].doit;
 137         op->dumpit      = family->small_ops[i].dumpit;
 138         op->cmd         = family->small_ops[i].cmd;
 139         op->internal_flags = family->small_ops[i].internal_flags;
 140         op->flags       = family->small_ops[i].flags;
 141         op->validate    = family->small_ops[i].validate;
 142
 143         op->maxattr = family->maxattr;
 144         op->policy = family->policy;
 145 }
 146
 147 static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
 148                               struct genl_ops *op)
 149 {
 150         int i;
 151
 152         for (i = 0; i < family->n_small_ops; i++)
 153                 if (family->small_ops[i].cmd == cmd) {
 154                         genl_op_from_small(family, i, op);
 155                         return 0;
 156                 }
 157
 158         return -ENOENT;
 159 }
 160
 161 static int genl_get_cmd(u32 cmd, const struct genl_family *family,
 162                         struct genl_ops *op)
 163 {
 164         if (!genl_get_cmd_full(cmd, family, op))
 165                 return 0;
 166         return genl_get_cmd_small(cmd, family, op);
 167 }
 168
 169 static void genl_get_cmd_by_index(unsigned int i,
 170                                   const struct genl_family *family,
 171                                   struct genl_ops *op)
 172 {
 173         if (i < family->n_ops)
 174                 genl_op_from_full(family, i, op);
 175         else if (i < family->n_ops + family->n_small_ops)
 176                 genl_op_from_small(family, i - family->n_ops, op);
 177         else
 178                 WARN_ON_ONCE(1);
 179 }
 180
 181 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 182 {
 183         unsigned long *new_groups;
 184         int start = 0;
 185         int i;
 186         int id;
 187         bool fits;
 188
 189         do {
 190                 if (start == 0)
 191                         id = find_first_zero_bit(mc_groups,
 192                                                  mc_groups_longs *
 193                                                  BITS_PER_LONG);
 194                 else
 195                         id = find_next_zero_bit(mc_groups,
 196                                                 mc_groups_longs * BITS_PER_LONG,
 197                                                 start);
 198
 199                 fits = true;
 200                 for (i = id;
 201                      i < min_t(int, id + n_groups,
 202                                mc_groups_longs * BITS_PER_LONG);
 203                      i++) {
 204                         if (test_bit(i, mc_groups)) {
 205                                 start = i;
 206                                 fits = false;
 207                                 break;
 208                         }
 209                 }
 210
 211                 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
 212                         unsigned long new_longs = mc_groups_longs +
 213                                                   BITS_TO_LONGS(n_groups);
 214                         size_t nlen = new_longs * sizeof(unsigned long);
 215
 216                         if (mc_groups == &mc_group_start) {
 217                                 new_groups = kzalloc(nlen, GFP_KERNEL);
 218                                 if (!new_groups)
 219                                         return -ENOMEM;
 220                                 mc_groups = new_groups;
 221                                 *mc_groups = mc_group_start;
 222                         } else {
 223                                 new_groups = krealloc(mc_groups, nlen,
 224                                                       GFP_KERNEL);
 225                                 if (!new_groups)
 226                                         return -ENOMEM;
 227                                 mc_groups = new_groups;
 228                                 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
 229                                         mc_groups[mc_groups_longs + i] = 0;
 230                         }
 231                         mc_groups_longs = new_longs;
 232                 }
 233         } while (!fits);
 234
 235         for (i = id; i < id + n_groups; i++)
 236                 set_bit(i, mc_groups);
 237         *first_id = id;
 238         return 0;
 239 }
 240
 241 static struct genl_family genl_ctrl;
 242
 243 static int genl_validate_assign_mc_groups(struct genl_family *family)
 244 {
 245         int first_id;
 246         int n_groups = family->n_mcgrps;
 247         int err = 0, i;
 248         bool groups_allocated = false;
 249
 250         if (!n_groups)
 251                 return 0;
 252
 253         for (i = 0; i < n_groups; i++) {
 254                 const struct genl_multicast_group *grp = &family->mcgrps[i];
 255
 256                 if (WARN_ON(grp->name[0] == '\0'))
 257                         return -EINVAL;
 258                 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
 259                         return -EINVAL;
 260         }
 261
 262         /* special-case our own group and hacks */
 263         if (family == &genl_ctrl) {
 264                 first_id = GENL_ID_CTRL;
 265                 BUG_ON(n_groups != 1);
 266         } else if (strcmp(family->name, "NET_DM") == 0) {
 267                 first_id = 1;
 268                 BUG_ON(n_groups != 1);
 269         } else if (family->id == GENL_ID_VFS_DQUOT) {
 270                 first_id = GENL_ID_VFS_DQUOT;
 271                 BUG_ON(n_groups != 1);
 272         } else if (family->id == GENL_ID_PMCRAID) {
 273                 first_id = GENL_ID_PMCRAID;
 274                 BUG_ON(n_groups != 1);
 275         } else {
 276                 groups_allocated = true;
 277                 err = genl_allocate_reserve_groups(n_groups, &first_id);
 278                 if (err)
 279                         return err;
 280         }
 281
 282         family->mcgrp_offset = first_id;
 283
 284         /* if still initializing, can't and don't need to realloc bitmaps */
 285         if (!init_net.genl_sock)
 286                 return 0;
 287
 288         if (family->netnsok) {
 289                 struct net *net;
 290
 291                 netlink_table_grab();
 292                 rcu_read_lock();
 293                 for_each_net_rcu(net) {
 294                         err = __netlink_change_ngroups(net->genl_sock,
 295                                         mc_groups_longs * BITS_PER_LONG);
 296                         if (err) {
 297                                 /*
 298                                  * No need to roll back, can only fail if
 299                                  * memory allocation fails and then the
 300                                  * number of _possible_ groups has been
 301                                  * increased on some sockets which is ok.
 302                                  */
 303                                 break;
 304                         }
 305                 }
 306                 rcu_read_unlock();
 307                 netlink_table_ungrab();
 308         } else {
 309                 err = netlink_change_ngroups(init_net.genl_sock,
 310                                              mc_groups_longs * BITS_PER_LONG);
 311         }
 312
 313         if (groups_allocated && err) {
 314                 for (i = 0; i < family->n_mcgrps; i++)
 315                         clear_bit(family->mcgrp_offset + i, mc_groups);
 316         }
 317
 318         return err;
 319 }
 320
 321 static void genl_unregister_mc_groups(const struct genl_family *family)
 322 {
 323         struct net *net;
 324         int i;
 325
 326         netlink_table_grab();
 327         rcu_read_lock();
 328         for_each_net_rcu(net) {
 329                 for (i = 0; i < family->n_mcgrps; i++)
 330                         __netlink_clear_multicast_users(
 331                                 net->genl_sock, family->mcgrp_offset + i);
 332         }
 333         rcu_read_unlock();
 334         netlink_table_ungrab();
 335
 336         for (i = 0; i < family->n_mcgrps; i++) {
 337                 int grp_id = family->mcgrp_offset + i;
 338
 339                 if (grp_id != 1)
 340                         clear_bit(grp_id, mc_groups);
 341                 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
 342                                 &family->mcgrps[i], grp_id);
 343         }
 344 }
 345
 346 static int genl_validate_ops(const struct genl_family *family)
 347 {
 348         int i, j;
 349
 350         if (WARN_ON(family->n_ops && !family->ops) ||
 351             WARN_ON(family->n_small_ops && !family->small_ops))
 352                 return -EINVAL;
 353
 354         for (i = 0; i < genl_get_cmd_cnt(family); i++) {
 355                 struct genl_ops op;
 356
 357                 genl_get_cmd_by_index(i, family, &op);
 358                 if (op.dumpit == NULL && op.doit == NULL)
 359                         return -EINVAL;
 360                 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
 361                         struct genl_ops op2;
 362
 363                         genl_get_cmd_by_index(j, family, &op2);
 364                         if (op.cmd == op2.cmd)
 365                                 return -EINVAL;
 366                 }
 367         }
 368
 369         return 0;
 370 }
 371
 372 /**
 373  * genl_register_family - register a generic netlink family
 374  * @family: generic netlink family
 375  *
 376  * Registers the specified family after validating it first. Only one
 377  * family may be registered with the same family name or identifier.
 378  *
 379  * The family's ops, multicast groups and module pointer must already
 380  * be assigned.
 381  *
 382  * Return 0 on success or a negative error code.
 383  */
 384 int genl_register_family(struct genl_family *family)
 385 {
 386         int err, i;
 387         int start = GENL_START_ALLOC, end = GENL_MAX_ID;
 388
 389         err = genl_validate_ops(family);
 390         if (err)
 391                 return err;
 392
 393         genl_lock_all();
 394
 395         if (genl_family_find_byname(family->name)) {
 396                 err = -EEXIST;
 397                 goto errout_locked;
 398         }
 399
 400         /*
 401          * Sadly, a few cases need to be special-cased
 402          * due to them having previously abused the API
 403          * and having used their family ID also as their
 404          * multicast group ID, so we use reserved IDs
 405          * for both to be sure we can do that mapping.
 406          */
 407         if (family == &genl_ctrl) {
 408                 /* and this needs to be special for initial family lookups */
 409                 start = end = GENL_ID_CTRL;
 410         } else if (strcmp(family->name, "pmcraid") == 0) {
 411                 start = end = GENL_ID_PMCRAID;
 412         } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
 413                 start = end = GENL_ID_VFS_DQUOT;
 414         }
 415
 416         family->id = idr_alloc_cyclic(&genl_fam_idr, family,
 417                                       start, end + 1, GFP_KERNEL);
 418         if (family->id < 0) {
 419                 err = family->id;
 420                 goto errout_locked;
 421         }
 422
 423         err = genl_validate_assign_mc_groups(family);
 424         if (err)
 425                 goto errout_remove;
 426
 427         genl_unlock_all();
 428
 429         /* send all events */
 430         genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
 431         for (i = 0; i < family->n_mcgrps; i++)
 432                 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
 433                                 &family->mcgrps[i], family->mcgrp_offset + i);
 434
 435         return 0;
 436
 437 errout_remove:
 438         idr_remove(&genl_fam_idr, family->id);
 439 errout_locked:
 440         genl_unlock_all();
 441         return err;
 442 }
 443 EXPORT_SYMBOL(genl_register_family);
 444
 445 /**
 446  * genl_unregister_family - unregister generic netlink family
 447  * @family: generic netlink family
 448  *
 449  * Unregisters the specified family.
 450  *
 451  * Returns 0 on success or a negative error code.
 452  */
 453 int genl_unregister_family(const struct genl_family *family)
 454 {
 455         genl_lock_all();
 456
 457         if (!genl_family_find_byid(family->id)) {
 458                 genl_unlock_all();
 459                 return -ENOENT;
 460         }
 461
 462         genl_unregister_mc_groups(family);
 463
 464         idr_remove(&genl_fam_idr, family->id);
 465
 466         up_write(&cb_lock);
 467         wait_event(genl_sk_destructing_waitq,
 468                    atomic_read(&genl_sk_destructing_cnt) == 0);
 469         genl_unlock();
 470
 471         genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 472
 473         return 0;
 474 }
 475 EXPORT_SYMBOL(genl_unregister_family);
 476
 477 /**
 478  * genlmsg_put - Add generic netlink header to netlink message
 479  * @skb: socket buffer holding the message
 480  * @portid: netlink portid the message is addressed to
 481  * @seq: sequence number (usually the one of the sender)
 482  * @family: generic netlink family
 483  * @flags: netlink message flags
 484  * @cmd: generic netlink command
 485  *
 486  * Returns pointer to user specific header
 487  */
 488 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 489                   const struct genl_family *family, int flags, u8 cmd)
 490 {
 491         struct nlmsghdr *nlh;
 492         struct genlmsghdr *hdr;
 493
 494         nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 495                         family->hdrsize, flags);
 496         if (nlh == NULL)
 497                 return NULL;
 498
 499         hdr = nlmsg_data(nlh);
 500         hdr->cmd = cmd;
 501         hdr->version = family->version;
 502         hdr->reserved = 0;
 503
 504         return (char *) hdr + GENL_HDRLEN;
 505 }
 506 EXPORT_SYMBOL(genlmsg_put);
 507
 508 static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
 509 {
 510         return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
 511 }
 512
 513 static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
 514 {
 515         kfree(info);
 516 }
 517
 518 static struct nlattr **
 519 genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
 520                                 struct nlmsghdr *nlh,
 521                                 struct netlink_ext_ack *extack,
 522                                 const struct genl_ops *ops,
 523                                 int hdrlen,
 524                                 enum genl_validate_flags no_strict_flag)
 525 {
 526         enum netlink_validation validate = ops->validate & no_strict_flag ?
 527                                            NL_VALIDATE_LIBERAL :
 528                                            NL_VALIDATE_STRICT;
 529         struct nlattr **attrbuf;
 530         int err;
 531
 532         if (!ops->maxattr)
 533                 return NULL;
 534
 535         attrbuf = kmalloc_array(ops->maxattr + 1,
 536                                 sizeof(struct nlattr *), GFP_KERNEL);
 537         if (!attrbuf)
 538                 return ERR_PTR(-ENOMEM);
 539
 540         err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
 541                             validate, extack);
 542         if (err) {
 543                 kfree(attrbuf);
 544                 return ERR_PTR(err);
 545         }
 546         return attrbuf;
 547 }
 548
 549 static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
 550 {
 551         kfree(attrbuf);
 552 }
 553
 554 struct genl_start_context {
 555         const struct genl_family *family;
 556         struct nlmsghdr *nlh;
 557         struct netlink_ext_ack *extack;
 558         const struct genl_ops *ops;
 559         int hdrlen;
 560 };
 561
 562 static int genl_start(struct netlink_callback *cb)
 563 {
 564         struct genl_start_context *ctx = cb->data;
 565         const struct genl_ops *ops = ctx->ops;
 566         struct genl_dumpit_info *info;
 567         struct nlattr **attrs = NULL;
 568         int rc = 0;
 569
 570         if (ops->validate & GENL_DONT_VALIDATE_DUMP)
 571                 goto no_attrs;
 572
 573         if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
 574                 return -EINVAL;
 575
 576         attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
 577                                                 ops, ctx->hdrlen,
 578                                                 GENL_DONT_VALIDATE_DUMP_STRICT);
 579         if (IS_ERR(attrs))
 580                 return PTR_ERR(attrs);
 581
 582 no_attrs:
 583         info = genl_dumpit_info_alloc();
 584         if (!info) {
 585                 genl_family_rcv_msg_attrs_free(attrs);
 586                 return -ENOMEM;
 587         }
 588         info->family = ctx->family;
 589         info->op = *ops;
 590         info->attrs = attrs;
 591
 592         cb->data = info;
 593         if (ops->start) {
 594                 if (!ctx->family->parallel_ops)
 595                         genl_lock();
 596                 rc = ops->start(cb);
 597                 if (!ctx->family->parallel_ops)
 598                         genl_unlock();
 599         }
 600
 601         if (rc) {
 602                 genl_family_rcv_msg_attrs_free(info->attrs);
 603                 genl_dumpit_info_free(info);
 604                 cb->data = NULL;
 605         }
 606         return rc;
 607 }
 608
 609 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 610 {
 611         const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
 612         int rc;
 613
 614         genl_lock();
 615         rc = ops->dumpit(skb, cb);
 616         genl_unlock();
 617         return rc;
 618 }
 619
 620 static int genl_lock_done(struct netlink_callback *cb)
 621 {
 622         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 623         const struct genl_ops *ops = &info->op;
 624         int rc = 0;
 625
 626         if (ops->done) {
 627                 genl_lock();
 628                 rc = ops->done(cb);
 629                 genl_unlock();
 630         }
 631         genl_family_rcv_msg_attrs_free(info->attrs);
 632         genl_dumpit_info_free(info);
 633         return rc;
 634 }
 635
 636 static int genl_parallel_done(struct netlink_callback *cb)
 637 {
 638         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 639         const struct genl_ops *ops = &info->op;
 640         int rc = 0;
 641
 642         if (ops->done)
 643                 rc = ops->done(cb);
 644         genl_family_rcv_msg_attrs_free(info->attrs);
 645         genl_dumpit_info_free(info);
 646         return rc;
 647 }
 648
 649 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
 650                                       struct sk_buff *skb,
 651                                       struct nlmsghdr *nlh,
 652                                       struct netlink_ext_ack *extack,
 653                                       const struct genl_ops *ops,
 654                                       int hdrlen, struct net *net)
 655 {
 656         struct genl_start_context ctx;
 657         int err;
 658
 659         if (!ops->dumpit)
 660                 return -EOPNOTSUPP;
 661
 662         ctx.family = family;
 663         ctx.nlh = nlh;
 664         ctx.extack = extack;
 665         ctx.ops = ops;
 666         ctx.hdrlen = hdrlen;
 667
 668         if (!family->parallel_ops) {
 669                 struct netlink_dump_control c = {
 670                         .module = family->module,
 671                         .data = &ctx,
 672                         .start = genl_start,
 673                         .dump = genl_lock_dumpit,
 674                         .done = genl_lock_done,
 675                 };
 676
 677                 genl_unlock();
 678                 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 679                 genl_lock();
 680         } else {
 681                 struct netlink_dump_control c = {
 682                         .module = family->module,
 683                         .data = &ctx,
 684                         .start = genl_start,
 685                         .dump = ops->dumpit,
 686                         .done = genl_parallel_done,
 687                 };
 688
 689                 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 690         }
 691
 692         return err;
 693 }
 694
 695 static int genl_family_rcv_msg_doit(const struct genl_family *family,
 696                                     struct sk_buff *skb,
 697                                     struct nlmsghdr *nlh,
 698                                     struct netlink_ext_ack *extack,
 699                                     const struct genl_ops *ops,
 700                                     int hdrlen, struct net *net)
 701 {
 702         struct nlattr **attrbuf;
 703         struct genl_info info;
 704         int err;
 705
 706         if (!ops->doit)
 707                 return -EOPNOTSUPP;
 708
 709         attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
 710                                                   ops, hdrlen,
 711                                                   GENL_DONT_VALIDATE_STRICT);
 712         if (IS_ERR(attrbuf))
 713                 return PTR_ERR(attrbuf);
 714
 715         info.snd_seq = nlh->nlmsg_seq;
 716         info.snd_portid = NETLINK_CB(skb).portid;
 717         info.nlhdr = nlh;
 718         info.genlhdr = nlmsg_data(nlh);
 719         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 720         info.attrs = attrbuf;
 721         info.extack = extack;
 722         genl_info_net_set(&info, net);
 723         memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 724
 725         if (family->pre_doit) {
 726                 err = family->pre_doit(ops, skb, &info);
 727                 if (err)
 728                         goto out;
 729         }
 730
 731         err = ops->doit(skb, &info);
 732
 733         if (family->post_doit)
 734                 family->post_doit(ops, skb, &info);
 735
 736 out:
 737         genl_family_rcv_msg_attrs_free(attrbuf);
 738
 739         return err;
 740 }
 741
 742 static int genl_family_rcv_msg(const struct genl_family *family,
 743                                struct sk_buff *skb,
 744                                struct nlmsghdr *nlh,
 745                                struct netlink_ext_ack *extack)
 746 {
 747         struct net *net = sock_net(skb->sk);
 748         struct genlmsghdr *hdr = nlmsg_data(nlh);
 749         struct genl_ops op;
 750         int hdrlen;
 751
 752         /* this family doesn't exist in this netns */
 753         if (!family->netnsok && !net_eq(net, &init_net))
 754                 return -ENOENT;
 755
 756         hdrlen = GENL_HDRLEN + family->hdrsize;
 757         if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 758                 return -EINVAL;
 759
 760         if (genl_get_cmd(hdr->cmd, family, &op))
 761                 return -EOPNOTSUPP;
 762
 763         if ((op.flags & GENL_ADMIN_PERM) &&
 764             !netlink_capable(skb, CAP_NET_ADMIN))
 765                 return -EPERM;
 766
 767         if ((op.flags & GENL_UNS_ADMIN_PERM) &&
 768             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 769                 return -EPERM;
 770
 771         if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
 772                 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
 773                                                   &op, hdrlen, net);
 774         else
 775                 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
 776                                                 &op, hdrlen, net);
 777 }
 778
 779 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 780                         struct netlink_ext_ack *extack)
 781 {
 782         const struct genl_family *family;
 783         int err;
 784
 785         family = genl_family_find_byid(nlh->nlmsg_type);
 786         if (family == NULL)
 787                 return -ENOENT;
 788
 789         if (!family->parallel_ops)
 790                 genl_lock();
 791
 792         err = genl_family_rcv_msg(family, skb, nlh, extack);
 793
 794         if (!family->parallel_ops)
 795                 genl_unlock();
 796
 797         return err;
 798 }
 799
 800 static void genl_rcv(struct sk_buff *skb)
 801 {
 802         down_read(&cb_lock);
 803         netlink_rcv_skb(skb, &genl_rcv_msg);
 804         up_read(&cb_lock);
 805 }
 806
 807 /**************************************************************************
 808  * Controller
 809  **************************************************************************/
 810
 811 static struct genl_family genl_ctrl;
 812
 813 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
 814                           u32 flags, struct sk_buff *skb, u8 cmd)
 815 {
 816         void *hdr;
 817
 818         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 819         if (hdr == NULL)
 820                 return -1;
 821
 822         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 823             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 824             nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 825             nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 826             nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 827                 goto nla_put_failure;
 828
 829         if (genl_get_cmd_cnt(family)) {
 830                 struct nlattr *nla_ops;
 831                 int i;
 832
 833                 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
 834                 if (nla_ops == NULL)
 835                         goto nla_put_failure;
 836
 837                 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
 838                         struct nlattr *nest;
 839                         struct genl_ops op;
 840                         u32 op_flags;
 841
 842                         genl_get_cmd_by_index(i, family, &op);
 843                         op_flags = op.flags;
 844                         if (op.dumpit)
 845                                 op_flags |= GENL_CMD_CAP_DUMP;
 846                         if (op.doit)
 847                                 op_flags |= GENL_CMD_CAP_DO;
 848                         if (op.policy)
 849                                 op_flags |= GENL_CMD_CAP_HASPOL;
 850
 851                         nest = nla_nest_start_noflag(skb, i + 1);
 852                         if (nest == NULL)
 853                                 goto nla_put_failure;
 854
 855                         if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
 856                             nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 857                                 goto nla_put_failure;
 858
 859                         nla_nest_end(skb, nest);
 860                 }
 861
 862                 nla_nest_end(skb, nla_ops);
 863         }
 864
 865         if (family->n_mcgrps) {
 866                 struct nlattr *nla_grps;
 867                 int i;
 868
 869                 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
 870                 if (nla_grps == NULL)
 871                         goto nla_put_failure;
 872
 873                 for (i = 0; i < family->n_mcgrps; i++) {
 874                         struct nlattr *nest;
 875                         const struct genl_multicast_group *grp;
 876
 877                         grp = &family->mcgrps[i];
 878
 879                         nest = nla_nest_start_noflag(skb, i + 1);
 880                         if (nest == NULL)
 881                                 goto nla_put_failure;
 882
 883                         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
 884                                         family->mcgrp_offset + i) ||
 885                             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 886                                            grp->name))
 887                                 goto nla_put_failure;
 888
 889                         nla_nest_end(skb, nest);
 890                 }
 891                 nla_nest_end(skb, nla_grps);
 892         }
 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_fill_mcgrp_info(const struct genl_family *family,
 903                                 const struct genl_multicast_group *grp,
 904                                 int grp_id, u32 portid, u32 seq, u32 flags,
 905                                 struct sk_buff *skb, u8 cmd)
 906 {
 907         void *hdr;
 908         struct nlattr *nla_grps;
 909         struct nlattr *nest;
 910
 911         hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 912         if (hdr == NULL)
 913                 return -1;
 914
 915         if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 916             nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 917                 goto nla_put_failure;
 918
 919         nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
 920         if (nla_grps == NULL)
 921                 goto nla_put_failure;
 922
 923         nest = nla_nest_start_noflag(skb, 1);
 924         if (nest == NULL)
 925                 goto nla_put_failure;
 926
 927         if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
 928             nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 929                            grp->name))
 930                 goto nla_put_failure;
 931
 932         nla_nest_end(skb, nest);
 933         nla_nest_end(skb, nla_grps);
 934
 935         genlmsg_end(skb, hdr);
 936         return 0;
 937
 938 nla_put_failure:
 939         genlmsg_cancel(skb, hdr);
 940         return -EMSGSIZE;
 941 }
 942
 943 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 944 {
 945         int n = 0;
 946         struct genl_family *rt;
 947         struct net *net = sock_net(skb->sk);
 948         int fams_to_skip = cb->args[0];
 949         unsigned int id;
 950
 951         idr_for_each_entry(&genl_fam_idr, rt, id) {
 952                 if (!rt->netnsok && !net_eq(net, &init_net))
 953                         continue;
 954
 955                 if (n++ < fams_to_skip)
 956                         continue;
 957
 958                 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 959                                    cb->nlh->nlmsg_seq, NLM_F_MULTI,
 960                                    skb, CTRL_CMD_NEWFAMILY) < 0) {
 961                         n--;
 962                         break;
 963                 }
 964         }
 965
 966         cb->args[0] = n;
 967         return skb->len;
 968 }
 969
 970 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
 971                                              u32 portid, int seq, u8 cmd)
 972 {
 973         struct sk_buff *skb;
 974         int err;
 975
 976         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 977         if (skb == NULL)
 978                 return ERR_PTR(-ENOBUFS);
 979
 980         err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 981         if (err < 0) {
 982                 nlmsg_free(skb);
 983                 return ERR_PTR(err);
 984         }
 985
 986         return skb;
 987 }
 988
 989 static struct sk_buff *
 990 ctrl_build_mcgrp_msg(const struct genl_family *family,
 991                      const struct genl_multicast_group *grp,
 992                      int grp_id, u32 portid, int seq, u8 cmd)
 993 {
 994         struct sk_buff *skb;
 995         int err;
 996
 997         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 998         if (skb == NULL)
 999                 return ERR_PTR(-ENOBUFS);
1000
1001         err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1002                                    seq, 0, skb, cmd);
1003         if (err < 0) {
1004                 nlmsg_free(skb);
1005                 return ERR_PTR(err);
1006         }
1007
1008         return skb;
1009 }
1010
1011 static const struct nla_policy ctrl_policy_family[] = {
1012         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
1013         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1014                                     .len = GENL_NAMSIZ - 1 },
1015 };
1016
1017 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1018 {
1019         struct sk_buff *msg;
1020         const struct genl_family *res = NULL;
1021         int err = -EINVAL;
1022
1023         if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1024                 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1025                 res = genl_family_find_byid(id);
1026                 err = -ENOENT;
1027         }
1028
1029         if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1030                 char *name;
1031
1032                 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1033                 res = genl_family_find_byname(name);
1034 #ifdef CONFIG_MODULES
1035                 if (res == NULL) {
1036                         genl_unlock();
1037                         up_read(&cb_lock);
1038                         request_module("net-pf-%d-proto-%d-family-%s",
1039                                        PF_NETLINK, NETLINK_GENERIC, name);
1040                         down_read(&cb_lock);
1041                         genl_lock();
1042                         res = genl_family_find_byname(name);
1043                 }
1044 #endif
1045                 err = -ENOENT;
1046         }
1047
1048         if (res == NULL)
1049                 return err;
1050
1051         if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1052                 /* family doesn't exist here */
1053                 return -ENOENT;
1054         }
1055
1056         msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1057                                     CTRL_CMD_NEWFAMILY);
1058         if (IS_ERR(msg))
1059                 return PTR_ERR(msg);
1060
1061         return genlmsg_reply(msg, info);
1062 }
1063
1064 static int genl_ctrl_event(int event, const struct genl_family *family,
1065                            const struct genl_multicast_group *grp,
1066                            int grp_id)
1067 {
1068         struct sk_buff *msg;
1069
1070         /* genl is still initialising */
1071         if (!init_net.genl_sock)
1072                 return 0;
1073
1074         switch (event) {
1075         case CTRL_CMD_NEWFAMILY:
1076         case CTRL_CMD_DELFAMILY:
1077                 WARN_ON(grp);
1078                 msg = ctrl_build_family_msg(family, 0, 0, event);
1079                 break;
1080         case CTRL_CMD_NEWMCAST_GRP:
1081         case CTRL_CMD_DELMCAST_GRP:
1082                 BUG_ON(!grp);
1083                 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1084                 break;
1085         default:
1086                 return -EINVAL;
1087         }
1088
1089         if (IS_ERR(msg))
1090                 return PTR_ERR(msg);
1091
1092         if (!family->netnsok) {
1093                 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1094                                         0, GFP_KERNEL);
1095         } else {
1096                 rcu_read_lock();
1097                 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1098                                         0, GFP_ATOMIC);
1099                 rcu_read_unlock();
1100         }
1101
1102         return 0;
1103 }
1104
1105 struct ctrl_dump_policy_ctx {
1106         struct netlink_policy_dump_state *state;
1107         const struct genl_family *rt;
1108         unsigned int opidx;
1109         u32 op;
1110         u16 fam_id;
1111         u8 policies:1,
1112            single_op:1;
1113 };
1114
1115 static const struct nla_policy ctrl_policy_policy[] = {
1116         [CTRL_ATTR_FAMILY_ID]   = { .type = NLA_U16 },
1117         [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1118                                     .len = GENL_NAMSIZ - 1 },
1119         [CTRL_ATTR_OP]          = { .type = NLA_U32 },
1120 };
1121
1122 static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1123 {
1124         const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1125         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1126         struct nlattr **tb = info->attrs;
1127         const struct genl_family *rt;
1128         struct genl_ops op;
1129         int err, i;
1130
1131         BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1132
1133         if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1134                 return -EINVAL;
1135
1136         if (tb[CTRL_ATTR_FAMILY_ID]) {
1137                 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1138         } else {
1139                 rt = genl_family_find_byname(
1140                         nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1141                 if (!rt)
1142                         return -ENOENT;
1143                 ctx->fam_id = rt->id;
1144         }
1145
1146         rt = genl_family_find_byid(ctx->fam_id);
1147         if (!rt)
1148                 return -ENOENT;
1149
1150         ctx->rt = rt;
1151
1152         if (tb[CTRL_ATTR_OP]) {
1153                 ctx->single_op = true;
1154                 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1155
1156                 err = genl_get_cmd(ctx->op, rt, &op);
1157                 if (err) {
1158                         NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1159                         return err;
1160                 }
1161
1162                 if (!op.policy)
1163                         return -ENODATA;
1164
1165                 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1166                                                       op.maxattr);
1167         }
1168
1169         for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1170                 genl_get_cmd_by_index(i, rt, &op);
1171
1172                 if (op.policy) {
1173                         err = netlink_policy_dump_add_policy(&ctx->state,
1174                                                              op.policy,
1175                                                              op.maxattr);
1176                         if (err)
1177                                 return err;
1178                 }
1179         }
1180
1181         if (!ctx->state)
1182                 return -ENODATA;
1183         return 0;
1184 }
1185
1186 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1187                                   struct netlink_callback *cb)
1188 {
1189         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1190         void *hdr;
1191
1192         hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1193                           cb->nlh->nlmsg_seq, &genl_ctrl,
1194                           NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1195         if (!hdr)
1196                 return NULL;
1197
1198         if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1199                 return NULL;
1200
1201         return hdr;
1202 }
1203
1204 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1205                                   struct netlink_callback *cb,
1206                                   struct genl_ops *op)
1207 {
1208         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1209         struct nlattr *nest_pol, *nest_op;
1210         void *hdr;
1211         int idx;
1212
1213         /* skip if we have nothing to show */
1214         if (!op->policy)
1215                 return 0;
1216         if (!op->doit &&
1217             (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1218                 return 0;
1219
1220         hdr = ctrl_dumppolicy_prep(skb, cb);
1221         if (!hdr)
1222                 return -ENOBUFS;
1223
1224         nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1225         if (!nest_pol)
1226                 goto err;
1227
1228         nest_op = nla_nest_start(skb, op->cmd);
1229         if (!nest_op)
1230                 goto err;
1231
1232         /* for now both do/dump are always the same */
1233         idx = netlink_policy_dump_get_policy_idx(ctx->state,
1234                                                  op->policy,
1235                                                  op->maxattr);
1236
1237         if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1238                 goto err;
1239
1240         if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1241             nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1242                 goto err;
1243
1244         nla_nest_end(skb, nest_op);
1245         nla_nest_end(skb, nest_pol);
1246         genlmsg_end(skb, hdr);
1247
1248         return 0;
1249 err:
1250         genlmsg_cancel(skb, hdr);
1251         return -ENOBUFS;
1252 }
1253
1254 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1255 {
1256         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1257         void *hdr;
1258
1259         if (!ctx->policies) {
1260                 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1261                         struct genl_ops op;
1262
1263                         if (ctx->single_op) {
1264                                 int err;
1265
1266                                 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1267                                 if (WARN_ON(err))
1268                                         return skb->len;
1269
1270                                 /* break out of the loop after this one */
1271                                 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1272                         } else {
1273                                 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1274                         }
1275
1276                         if (ctrl_dumppolicy_put_op(skb, cb, &op))
1277                                 return skb->len;
1278
1279                         ctx->opidx++;
1280                 }
1281
1282                 /* completed with the per-op policy index list */
1283                 ctx->policies = true;
1284         }
1285
1286         while (netlink_policy_dump_loop(ctx->state)) {
1287                 struct nlattr *nest;
1288
1289                 hdr = ctrl_dumppolicy_prep(skb, cb);
1290                 if (!hdr)
1291                         goto nla_put_failure;
1292
1293                 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1294                 if (!nest)
1295                         goto nla_put_failure;
1296
1297                 if (netlink_policy_dump_write(skb, ctx->state))
1298                         goto nla_put_failure;
1299
1300                 nla_nest_end(skb, nest);
1301
1302                 genlmsg_end(skb, hdr);
1303         }
1304
1305         return skb->len;
1306
1307 nla_put_failure:
1308         genlmsg_cancel(skb, hdr);
1309         return skb->len;
1310 }
1311
1312 static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1313 {
1314         struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1315
1316         netlink_policy_dump_free(ctx->state);
1317         return 0;
1318 }
1319
1320 static const struct genl_ops genl_ctrl_ops[] = {
1321         {
1322                 .cmd            = CTRL_CMD_GETFAMILY,
1323                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1324                 .policy         = ctrl_policy_family,
1325                 .maxattr        = ARRAY_SIZE(ctrl_policy_family) - 1,
1326                 .doit           = ctrl_getfamily,
1327                 .dumpit         = ctrl_dumpfamily,
1328         },
1329         {
1330                 .cmd            = CTRL_CMD_GETPOLICY,
1331                 .policy         = ctrl_policy_policy,
1332                 .maxattr        = ARRAY_SIZE(ctrl_policy_policy) - 1,
1333                 .start          = ctrl_dumppolicy_start,
1334                 .dumpit         = ctrl_dumppolicy,
1335                 .done           = ctrl_dumppolicy_done,
1336         },
1337 };
1338
1339 static const struct genl_multicast_group genl_ctrl_groups[] = {
1340         { .name = "notify", },
1341 };
1342
1343 static struct genl_family genl_ctrl __ro_after_init = {
1344         .module = THIS_MODULE,
1345         .ops = genl_ctrl_ops,
1346         .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1347         .mcgrps = genl_ctrl_groups,
1348         .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1349         .id = GENL_ID_CTRL,
1350         .name = "nlctrl",
1351         .version = 0x2,
1352         .netnsok = true,
1353 };
1354
1355 static int genl_bind(struct net *net, int group)
1356 {
1357         const struct genl_family *family;
1358         unsigned int id;
1359         int ret = 0;
1360
1361         genl_lock_all();
1362
1363         idr_for_each_entry(&genl_fam_idr, family, id) {
1364                 const struct genl_multicast_group *grp;
1365                 int i;
1366
1367                 if (family->n_mcgrps == 0)
1368                         continue;
1369
1370                 i = group - family->mcgrp_offset;
1371                 if (i < 0 || i >= family->n_mcgrps)
1372                         continue;
1373
1374                 grp = &family->mcgrps[i];
1375                 if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
1376                     !ns_capable(net->user_ns, CAP_NET_ADMIN))
1377                         ret = -EPERM;
1378
1379                 break;
1380         }
1381
1382         genl_unlock_all();
1383         return ret;
1384 }
1385
1386 static int __net_init genl_pernet_init(struct net *net)
1387 {
1388         struct netlink_kernel_cfg cfg = {
1389                 .input          = genl_rcv,
1390                 .flags          = NL_CFG_F_NONROOT_RECV,
1391                 .bind           = genl_bind,
1392         };
1393
1394         /* we'll bump the group number right afterwards */
1395         net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1396
1397         if (!net->genl_sock && net_eq(net, &init_net))
1398                 panic("GENL: Cannot initialize generic netlink\n");
1399
1400         if (!net->genl_sock)
1401                 return -ENOMEM;
1402
1403         return 0;
1404 }
1405
1406 static void __net_exit genl_pernet_exit(struct net *net)
1407 {
1408         netlink_kernel_release(net->genl_sock);
1409         net->genl_sock = NULL;
1410 }
1411
1412 static struct pernet_operations genl_pernet_ops = {
1413         .init = genl_pernet_init,
1414         .exit = genl_pernet_exit,
1415 };
1416
1417 static int __init genl_init(void)
1418 {
1419         int err;
1420
1421         err = genl_register_family(&genl_ctrl);
1422         if (err < 0)
1423                 goto problem;
1424
1425         err = register_pernet_subsys(&genl_pernet_ops);
1426         if (err)
1427                 goto problem;
1428
1429         return 0;
1430
1431 problem:
1432         panic("GENL: Cannot register controller: %d\n", err);
1433 }
1434
1435 core_initcall(genl_init);
1436
1437 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1438                          gfp_t flags)
1439 {
1440         struct sk_buff *tmp;
1441         struct net *net, *prev = NULL;
1442         bool delivered = false;
1443         int err;
1444
1445         for_each_net_rcu(net) {
1446                 if (prev) {
1447                         tmp = skb_clone(skb, flags);
1448                         if (!tmp) {
1449                                 err = -ENOMEM;
1450                                 goto error;
1451                         }
1452                         err = nlmsg_multicast(prev->genl_sock, tmp,
1453                                               portid, group, flags);
1454                         if (!err)
1455                                 delivered = true;
1456                         else if (err != -ESRCH)
1457                                 goto error;
1458                 }
1459
1460                 prev = net;
1461         }
1462
1463         err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1464         if (!err)
1465                 delivered = true;
1466         else if (err != -ESRCH)
1467                 return err;
1468         return delivered ? 0 : -ESRCH;
1469  error:
1470         kfree_skb(skb);
1471         return err;
1472 }
1473
1474 int genlmsg_multicast_allns(const struct genl_family *family,
1475                             struct sk_buff *skb, u32 portid,
1476                             unsigned int group, gfp_t flags)
1477 {
1478         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1479                 return -EINVAL;
1480
1481         group = family->mcgrp_offset + group;
1482         return genlmsg_mcast(skb, portid, group, flags);
1483 }
1484 EXPORT_SYMBOL(genlmsg_multicast_allns);
1485
1486 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1487                  struct genl_info *info, u32 group, gfp_t flags)
1488 {
1489         struct net *net = genl_info_net(info);
1490         struct sock *sk = net->genl_sock;
1491
1492         if (WARN_ON_ONCE(group >= family->n_mcgrps))
1493                 return;
1494
1495         group = family->mcgrp_offset + group;
1496         nlmsg_notify(sk, skb, info->snd_portid, group,
1497                      nlmsg_report(info->nlhdr), flags);
1498 }
1499 EXPORT_SYMBOL(genl_notify);