1/*
   2 * NETLINK      Generic Netlink Family
   3 *
   4 * 		Authors:	Jamal Hadi Salim
   5 * 				Thomas Graf <tgraf@suug.ch>
   6 *				Johannes Berg <johannes@sipsolutions.net>
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/kernel.h>
  11#include <linux/slab.h>
  12#include <linux/errno.h>
  13#include <linux/types.h>
  14#include <linux/socket.h>
  15#include <linux/string.h>
  16#include <linux/skbuff.h>
  17#include <linux/mutex.h>
  18#include <linux/bitmap.h>
  19#include <linux/rwsem.h>
  20#include <linux/idr.h>
  21#include <net/sock.h>
  22#include <net/genetlink.h>
  23
  24static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
  25static DECLARE_RWSEM(cb_lock);
  26
  27atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
  28DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
  29
  30void genl_lock(void)
  31{
  32	mutex_lock(&genl_mutex);
  33}
  34EXPORT_SYMBOL(genl_lock);
  35
  36void genl_unlock(void)
  37{
  38	mutex_unlock(&genl_mutex);
  39}
  40EXPORT_SYMBOL(genl_unlock);
  41
  42#ifdef CONFIG_LOCKDEP
  43bool lockdep_genl_is_held(void)
  44{
  45	return lockdep_is_held(&genl_mutex);
  46}
  47EXPORT_SYMBOL(lockdep_genl_is_held);
  48#endif
  49
  50static void genl_lock_all(void)
  51{
  52	down_write(&cb_lock);
  53	genl_lock();
  54}
  55
  56static void genl_unlock_all(void)
  57{
  58	genl_unlock();
  59	up_write(&cb_lock);
  60}
  61
  62static DEFINE_IDR(genl_fam_idr);
  63
  64/*
  65 * Bitmap of multicast groups that are currently in use.
  66 *
  67 * To avoid an allocation at boot of just one unsigned long,
  68 * declare it global instead.
  69 * Bit 0 is marked as already used since group 0 is invalid.
  70 * Bit 1 is marked as already used since the drop-monitor code
  71 * abuses the API and thinks it can statically use group 1.
  72 * That group will typically conflict with other groups that
  73 * any proper users use.
  74 * Bit 16 is marked as used since it's used for generic netlink
  75 * and the code no longer marks pre-reserved IDs as used.
  76 * Bit 17 is marked as already used since the VFS quota code
  77 * also abused this API and relied on family == group ID, we
  78 * cater to that by giving it a static family and group ID.
  79 * Bit 18 is marked as already used since the PMCRAID driver
  80 * did the same thing as the VFS quota code (maybe copied?)
  81 */
  82static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
  83				      BIT(GENL_ID_VFS_DQUOT) |
  84				      BIT(GENL_ID_PMCRAID);
  85static unsigned long *mc_groups = &mc_group_start;
  86static unsigned long mc_groups_longs = 1;
  87
 
 
 
 
 
 
  88static int genl_ctrl_event(int event, const struct genl_family *family,
  89			   const struct genl_multicast_group *grp,
  90			   int grp_id);
  91
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  92static const struct genl_family *genl_family_find_byid(unsigned int id)
  93{
  94	return idr_find(&genl_fam_idr, id);
  95}
  96
  97static const struct genl_family *genl_family_find_byname(char *name)
  98{
  99	const struct genl_family *family;
 100	unsigned int id;
 101
 102	idr_for_each_entry(&genl_fam_idr, family, id)
 103		if (strcmp(family->name, name) == 0)
 104			return family;
 105
 106	return NULL;
 107}
 108
 109static const struct genl_ops *genl_get_cmd(u8 cmd,
 110					   const struct genl_family *family)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 111{
 112	int i;
 113
 114	for (i = 0; i < family->n_ops; i++)
 115		if (family->ops[i].cmd == cmd)
 116			return &family->ops[i];
 
 
 117
 118	return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 119}
 120
 121static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 122{
 123	unsigned long *new_groups;
 124	int start = 0;
 125	int i;
 126	int id;
 127	bool fits;
 128
 129	do {
 130		if (start == 0)
 131			id = find_first_zero_bit(mc_groups,
 132						 mc_groups_longs *
 133						 BITS_PER_LONG);
 134		else
 135			id = find_next_zero_bit(mc_groups,
 136						mc_groups_longs * BITS_PER_LONG,
 137						start);
 138
 139		fits = true;
 140		for (i = id;
 141		     i < min_t(int, id + n_groups,
 142			       mc_groups_longs * BITS_PER_LONG);
 143		     i++) {
 144			if (test_bit(i, mc_groups)) {
 145				start = i;
 146				fits = false;
 147				break;
 148			}
 149		}
 150
 151		if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
 152			unsigned long new_longs = mc_groups_longs +
 153						  BITS_TO_LONGS(n_groups);
 154			size_t nlen = new_longs * sizeof(unsigned long);
 155
 156			if (mc_groups == &mc_group_start) {
 157				new_groups = kzalloc(nlen, GFP_KERNEL);
 158				if (!new_groups)
 159					return -ENOMEM;
 160				mc_groups = new_groups;
 161				*mc_groups = mc_group_start;
 162			} else {
 163				new_groups = krealloc(mc_groups, nlen,
 164						      GFP_KERNEL);
 165				if (!new_groups)
 166					return -ENOMEM;
 167				mc_groups = new_groups;
 168				for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
 169					mc_groups[mc_groups_longs + i] = 0;
 170			}
 171			mc_groups_longs = new_longs;
 172		}
 173	} while (!fits);
 174
 175	for (i = id; i < id + n_groups; i++)
 176		set_bit(i, mc_groups);
 177	*first_id = id;
 178	return 0;
 179}
 180
 181static struct genl_family genl_ctrl;
 182
 183static int genl_validate_assign_mc_groups(struct genl_family *family)
 184{
 185	int first_id;
 186	int n_groups = family->n_mcgrps;
 187	int err = 0, i;
 188	bool groups_allocated = false;
 189
 190	if (!n_groups)
 191		return 0;
 192
 193	for (i = 0; i < n_groups; i++) {
 194		const struct genl_multicast_group *grp = &family->mcgrps[i];
 195
 196		if (WARN_ON(grp->name[0] == '\0'))
 197			return -EINVAL;
 198		if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
 199			return -EINVAL;
 200	}
 201
 202	/* special-case our own group and hacks */
 203	if (family == &genl_ctrl) {
 204		first_id = GENL_ID_CTRL;
 205		BUG_ON(n_groups != 1);
 206	} else if (strcmp(family->name, "NET_DM") == 0) {
 207		first_id = 1;
 208		BUG_ON(n_groups != 1);
 209	} else if (family->id == GENL_ID_VFS_DQUOT) {
 210		first_id = GENL_ID_VFS_DQUOT;
 211		BUG_ON(n_groups != 1);
 212	} else if (family->id == GENL_ID_PMCRAID) {
 213		first_id = GENL_ID_PMCRAID;
 214		BUG_ON(n_groups != 1);
 215	} else {
 216		groups_allocated = true;
 217		err = genl_allocate_reserve_groups(n_groups, &first_id);
 218		if (err)
 219			return err;
 220	}
 221
 222	family->mcgrp_offset = first_id;
 223
 224	/* if still initializing, can't and don't need to to realloc bitmaps */
 225	if (!init_net.genl_sock)
 226		return 0;
 227
 228	if (family->netnsok) {
 229		struct net *net;
 230
 231		netlink_table_grab();
 232		rcu_read_lock();
 233		for_each_net_rcu(net) {
 234			err = __netlink_change_ngroups(net->genl_sock,
 235					mc_groups_longs * BITS_PER_LONG);
 236			if (err) {
 237				/*
 238				 * No need to roll back, can only fail if
 239				 * memory allocation fails and then the
 240				 * number of _possible_ groups has been
 241				 * increased on some sockets which is ok.
 242				 */
 243				break;
 244			}
 245		}
 246		rcu_read_unlock();
 247		netlink_table_ungrab();
 248	} else {
 249		err = netlink_change_ngroups(init_net.genl_sock,
 250					     mc_groups_longs * BITS_PER_LONG);
 251	}
 252
 253	if (groups_allocated && err) {
 254		for (i = 0; i < family->n_mcgrps; i++)
 255			clear_bit(family->mcgrp_offset + i, mc_groups);
 256	}
 257
 258	return err;
 259}
 260
 261static void genl_unregister_mc_groups(const struct genl_family *family)
 262{
 263	struct net *net;
 264	int i;
 265
 266	netlink_table_grab();
 267	rcu_read_lock();
 268	for_each_net_rcu(net) {
 269		for (i = 0; i < family->n_mcgrps; i++)
 270			__netlink_clear_multicast_users(
 271				net->genl_sock, family->mcgrp_offset + i);
 272	}
 273	rcu_read_unlock();
 274	netlink_table_ungrab();
 275
 276	for (i = 0; i < family->n_mcgrps; i++) {
 277		int grp_id = family->mcgrp_offset + i;
 278
 279		if (grp_id != 1)
 280			clear_bit(grp_id, mc_groups);
 281		genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
 282				&family->mcgrps[i], grp_id);
 283	}
 284}
 285
 
 
 
 
 
 
 
 
 286static int genl_validate_ops(const struct genl_family *family)
 287{
 288	const struct genl_ops *ops = family->ops;
 289	unsigned int n_ops = family->n_ops;
 290	int i, j;
 291
 292	if (WARN_ON(n_ops && !ops))
 
 
 293		return -EINVAL;
 294
 295	if (!n_ops)
 296		return 0;
 
 297
 298	for (i = 0; i < n_ops; i++) {
 299		if (ops[i].dumpit == NULL && ops[i].doit == NULL)
 300			return -EINVAL;
 301		for (j = i + 1; j < n_ops; j++)
 302			if (ops[i].cmd == ops[j].cmd)
 
 
 303				return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 304	}
 305
 306	return 0;
 307}
 308
 309/**
 310 * genl_register_family - register a generic netlink family
 311 * @family: generic netlink family
 312 *
 313 * Registers the specified family after validating it first. Only one
 314 * family may be registered with the same family name or identifier.
 315 *
 316 * The family's ops, multicast groups and module pointer must already
 317 * be assigned.
 318 *
 319 * Return 0 on success or a negative error code.
 320 */
 321int genl_register_family(struct genl_family *family)
 322{
 323	int err, i;
 324	int start = GENL_START_ALLOC, end = GENL_MAX_ID;
 325
 326	err = genl_validate_ops(family);
 327	if (err)
 328		return err;
 329
 330	genl_lock_all();
 331
 332	if (genl_family_find_byname(family->name)) {
 333		err = -EEXIST;
 334		goto errout_locked;
 335	}
 336
 337	/*
 338	 * Sadly, a few cases need to be special-cased
 339	 * due to them having previously abused the API
 340	 * and having used their family ID also as their
 341	 * multicast group ID, so we use reserved IDs
 342	 * for both to be sure we can do that mapping.
 343	 */
 344	if (family == &genl_ctrl) {
 345		/* and this needs to be special for initial family lookups */
 346		start = end = GENL_ID_CTRL;
 347	} else if (strcmp(family->name, "pmcraid") == 0) {
 348		start = end = GENL_ID_PMCRAID;
 349	} else if (strcmp(family->name, "VFS_DQUOT") == 0) {
 350		start = end = GENL_ID_VFS_DQUOT;
 351	}
 352
 353	if (family->maxattr && !family->parallel_ops) {
 354		family->attrbuf = kmalloc((family->maxattr+1) *
 355					sizeof(struct nlattr *), GFP_KERNEL);
 356		if (family->attrbuf == NULL) {
 357			err = -ENOMEM;
 358			goto errout_locked;
 359		}
 360	} else
 361		family->attrbuf = NULL;
 362
 363	family->id = idr_alloc(&genl_fam_idr, family,
 364			       start, end + 1, GFP_KERNEL);
 365	if (family->id < 0) {
 366		err = family->id;
 367		goto errout_locked;
 368	}
 369
 370	err = genl_validate_assign_mc_groups(family);
 371	if (err)
 372		goto errout_remove;
 373
 374	genl_unlock_all();
 375
 376	/* send all events */
 377	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
 378	for (i = 0; i < family->n_mcgrps; i++)
 379		genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
 380				&family->mcgrps[i], family->mcgrp_offset + i);
 381
 382	return 0;
 383
 384errout_remove:
 385	idr_remove(&genl_fam_idr, family->id);
 386	kfree(family->attrbuf);
 387errout_locked:
 388	genl_unlock_all();
 389	return err;
 390}
 391EXPORT_SYMBOL(genl_register_family);
 392
 393/**
 394 * genl_unregister_family - unregister generic netlink family
 395 * @family: generic netlink family
 396 *
 397 * Unregisters the specified family.
 398 *
 399 * Returns 0 on success or a negative error code.
 400 */
 401int genl_unregister_family(const struct genl_family *family)
 402{
 403	genl_lock_all();
 404
 405	if (!genl_family_find_byid(family->id)) {
 406		genl_unlock_all();
 407		return -ENOENT;
 408	}
 409
 410	genl_unregister_mc_groups(family);
 411
 412	idr_remove(&genl_fam_idr, family->id);
 413
 414	up_write(&cb_lock);
 415	wait_event(genl_sk_destructing_waitq,
 416		   atomic_read(&genl_sk_destructing_cnt) == 0);
 417	genl_unlock();
 418
 419	kfree(family->attrbuf);
 420
 421	genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 422
 423	return 0;
 424}
 425EXPORT_SYMBOL(genl_unregister_family);
 426
 427/**
 428 * genlmsg_put - Add generic netlink header to netlink message
 429 * @skb: socket buffer holding the message
 430 * @portid: netlink portid the message is addressed to
 431 * @seq: sequence number (usually the one of the sender)
 432 * @family: generic netlink family
 433 * @flags: netlink message flags
 434 * @cmd: generic netlink command
 435 *
 436 * Returns pointer to user specific header
 437 */
 438void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 439		  const struct genl_family *family, int flags, u8 cmd)
 440{
 441	struct nlmsghdr *nlh;
 442	struct genlmsghdr *hdr;
 443
 444	nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
 445			family->hdrsize, flags);
 446	if (nlh == NULL)
 447		return NULL;
 448
 449	hdr = nlmsg_data(nlh);
 450	hdr->cmd = cmd;
 451	hdr->version = family->version;
 452	hdr->reserved = 0;
 453
 454	return (char *) hdr + GENL_HDRLEN;
 455}
 456EXPORT_SYMBOL(genlmsg_put);
 457
 458static int genl_lock_start(struct netlink_callback *cb)
 
 
 
 
 
 459{
 460	/* our ops are always const - netlink API doesn't propagate that */
 461	const struct genl_ops *ops = cb->data;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 462	int rc = 0;
 463
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 464	if (ops->start) {
 465		genl_lock();
 
 466		rc = ops->start(cb);
 467		genl_unlock();
 
 
 
 
 
 
 
 468	}
 469	return rc;
 470}
 471
 472static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 473{
 474	/* our ops are always const - netlink API doesn't propagate that */
 475	const struct genl_ops *ops = cb->data;
 476	int rc;
 477
 478	genl_lock();
 479	rc = ops->dumpit(skb, cb);
 480	genl_unlock();
 481	return rc;
 482}
 483
 484static int genl_lock_done(struct netlink_callback *cb)
 485{
 486	/* our ops are always const - netlink API doesn't propagate that */
 487	const struct genl_ops *ops = cb->data;
 488	int rc = 0;
 489
 490	if (ops->done) {
 491		genl_lock();
 492		rc = ops->done(cb);
 493		genl_unlock();
 494	}
 
 
 495	return rc;
 496}
 497
 498static int genl_family_rcv_msg(const struct genl_family *family,
 499			       struct sk_buff *skb,
 500			       struct nlmsghdr *nlh)
 501{
 502	const struct genl_ops *ops;
 503	struct net *net = sock_net(skb->sk);
 504	struct genl_info info;
 505	struct genlmsghdr *hdr = nlmsg_data(nlh);
 506	struct nlattr **attrbuf;
 507	int hdrlen, err;
 508
 509	/* this family doesn't exist in this netns */
 510	if (!family->netnsok && !net_eq(net, &init_net))
 511		return -ENOENT;
 512
 513	hdrlen = GENL_HDRLEN + family->hdrsize;
 514	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 515		return -EINVAL;
 516
 517	ops = genl_get_cmd(hdr->cmd, family);
 518	if (ops == NULL)
 519		return -EOPNOTSUPP;
 520
 521	if ((ops->flags & GENL_ADMIN_PERM) &&
 522	    !netlink_capable(skb, CAP_NET_ADMIN))
 523		return -EPERM;
 524
 525	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
 526	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 527		return -EPERM;
 528
 529	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
 530		int rc;
 531
 532		if (ops->dumpit == NULL)
 533			return -EOPNOTSUPP;
 534
 535		if (!family->parallel_ops) {
 536			struct netlink_dump_control c = {
 537				.module = family->module,
 538				/* we have const, but the netlink API doesn't */
 539				.data = (void *)ops,
 540				.start = genl_lock_start,
 541				.dump = genl_lock_dumpit,
 542				.done = genl_lock_done,
 543			};
 544
 545			genl_unlock();
 546			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 547			genl_lock();
 
 
 
 
 
 
 548
 549		} else {
 550			struct netlink_dump_control c = {
 551				.module = family->module,
 552				.start = ops->start,
 553				.dump = ops->dumpit,
 554				.done = ops->done,
 555			};
 
 
 
 
 
 
 
 556
 557			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 558		}
 
 
 
 
 
 
 
 
 
 559
 560		return rc;
 561	}
 562
 563	if (ops->doit == NULL)
 564		return -EOPNOTSUPP;
 565
 566	if (family->maxattr && family->parallel_ops) {
 567		attrbuf = kmalloc((family->maxattr+1) *
 568					sizeof(struct nlattr *), GFP_KERNEL);
 569		if (attrbuf == NULL)
 570			return -ENOMEM;
 571	} else
 572		attrbuf = family->attrbuf;
 573
 574	if (attrbuf) {
 575		err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
 576				  ops->policy);
 577		if (err < 0)
 578			goto out;
 579	}
 
 
 580
 581	info.snd_seq = nlh->nlmsg_seq;
 582	info.snd_portid = NETLINK_CB(skb).portid;
 583	info.nlhdr = nlh;
 584	info.genlhdr = nlmsg_data(nlh);
 585	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
 586	info.attrs = attrbuf;
 
 587	genl_info_net_set(&info, net);
 588	memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 589
 590	if (family->pre_doit) {
 591		err = family->pre_doit(ops, skb, &info);
 592		if (err)
 593			goto out;
 594	}
 595
 596	err = ops->doit(skb, &info);
 597
 598	if (family->post_doit)
 599		family->post_doit(ops, skb, &info);
 600
 601out:
 602	if (family->parallel_ops)
 603		kfree(attrbuf);
 604
 605	return err;
 606}
 607
 608static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 609{
 610	const struct genl_family *family;
 611	int err;
 612
 613	family = genl_family_find_byid(nlh->nlmsg_type);
 614	if (family == NULL)
 615		return -ENOENT;
 616
 617	if (!family->parallel_ops)
 618		genl_lock();
 619
 620	err = genl_family_rcv_msg(family, skb, nlh);
 621
 622	if (!family->parallel_ops)
 623		genl_unlock();
 624
 625	return err;
 626}
 627
 628static void genl_rcv(struct sk_buff *skb)
 629{
 630	down_read(&cb_lock);
 631	netlink_rcv_skb(skb, &genl_rcv_msg);
 632	up_read(&cb_lock);
 633}
 634
 635/**************************************************************************
 636 * Controller
 637 **************************************************************************/
 638
 639static struct genl_family genl_ctrl;
 640
 641static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
 642			  u32 flags, struct sk_buff *skb, u8 cmd)
 643{
 
 644	void *hdr;
 645
 646	hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 647	if (hdr == NULL)
 648		return -1;
 649
 650	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 651	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
 652	    nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
 653	    nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
 654	    nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 655		goto nla_put_failure;
 656
 657	if (family->n_ops) {
 658		struct nlattr *nla_ops;
 659		int i;
 660
 661		nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
 662		if (nla_ops == NULL)
 663			goto nla_put_failure;
 664
 665		for (i = 0; i < family->n_ops; i++) {
 666			struct nlattr *nest;
 667			const struct genl_ops *ops = &family->ops[i];
 668			u32 op_flags = ops->flags;
 669
 670			if (ops->dumpit)
 671				op_flags |= GENL_CMD_CAP_DUMP;
 672			if (ops->doit)
 673				op_flags |= GENL_CMD_CAP_DO;
 674			if (ops->policy)
 675				op_flags |= GENL_CMD_CAP_HASPOL;
 676
 677			nest = nla_nest_start(skb, i + 1);
 678			if (nest == NULL)
 679				goto nla_put_failure;
 680
 681			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
 682			    nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 683				goto nla_put_failure;
 684
 685			nla_nest_end(skb, nest);
 686		}
 687
 688		nla_nest_end(skb, nla_ops);
 689	}
 690
 691	if (family->n_mcgrps) {
 692		struct nlattr *nla_grps;
 693		int i;
 694
 695		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 696		if (nla_grps == NULL)
 697			goto nla_put_failure;
 698
 699		for (i = 0; i < family->n_mcgrps; i++) {
 700			struct nlattr *nest;
 701			const struct genl_multicast_group *grp;
 702
 703			grp = &family->mcgrps[i];
 704
 705			nest = nla_nest_start(skb, i + 1);
 706			if (nest == NULL)
 707				goto nla_put_failure;
 708
 709			if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
 710					family->mcgrp_offset + i) ||
 711			    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 712					   grp->name))
 713				goto nla_put_failure;
 714
 715			nla_nest_end(skb, nest);
 716		}
 717		nla_nest_end(skb, nla_grps);
 718	}
 719
 720	genlmsg_end(skb, hdr);
 721	return 0;
 722
 723nla_put_failure:
 724	genlmsg_cancel(skb, hdr);
 725	return -EMSGSIZE;
 726}
 727
 728static int ctrl_fill_mcgrp_info(const struct genl_family *family,
 729				const struct genl_multicast_group *grp,
 730				int grp_id, u32 portid, u32 seq, u32 flags,
 731				struct sk_buff *skb, u8 cmd)
 732{
 733	void *hdr;
 734	struct nlattr *nla_grps;
 735	struct nlattr *nest;
 736
 737	hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 738	if (hdr == NULL)
 739		return -1;
 740
 741	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 742	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
 743		goto nla_put_failure;
 744
 745	nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 746	if (nla_grps == NULL)
 747		goto nla_put_failure;
 748
 749	nest = nla_nest_start(skb, 1);
 750	if (nest == NULL)
 751		goto nla_put_failure;
 752
 753	if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
 754	    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
 755			   grp->name))
 756		goto nla_put_failure;
 757
 758	nla_nest_end(skb, nest);
 759	nla_nest_end(skb, nla_grps);
 760
 761	genlmsg_end(skb, hdr);
 762	return 0;
 763
 764nla_put_failure:
 765	genlmsg_cancel(skb, hdr);
 766	return -EMSGSIZE;
 767}
 768
 769static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 770{
 771	int n = 0;
 772	struct genl_family *rt;
 773	struct net *net = sock_net(skb->sk);
 774	int fams_to_skip = cb->args[0];
 775	unsigned int id;
 776
 777	idr_for_each_entry(&genl_fam_idr, rt, id) {
 778		if (!rt->netnsok && !net_eq(net, &init_net))
 779			continue;
 780
 781		if (n++ < fams_to_skip)
 782			continue;
 783
 784		if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
 785				   cb->nlh->nlmsg_seq, NLM_F_MULTI,
 786				   skb, CTRL_CMD_NEWFAMILY) < 0) {
 787			n--;
 788			break;
 789		}
 790	}
 791
 792	cb->args[0] = n;
 793	return skb->len;
 794}
 795
 796static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
 797					     u32 portid, int seq, u8 cmd)
 798{
 799	struct sk_buff *skb;
 800	int err;
 801
 802	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 803	if (skb == NULL)
 804		return ERR_PTR(-ENOBUFS);
 805
 806	err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
 807	if (err < 0) {
 808		nlmsg_free(skb);
 809		return ERR_PTR(err);
 810	}
 811
 812	return skb;
 813}
 814
 815static struct sk_buff *
 816ctrl_build_mcgrp_msg(const struct genl_family *family,
 817		     const struct genl_multicast_group *grp,
 818		     int grp_id, u32 portid, int seq, u8 cmd)
 819{
 820	struct sk_buff *skb;
 821	int err;
 822
 823	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 824	if (skb == NULL)
 825		return ERR_PTR(-ENOBUFS);
 826
 827	err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
 828				   seq, 0, skb, cmd);
 829	if (err < 0) {
 830		nlmsg_free(skb);
 831		return ERR_PTR(err);
 832	}
 833
 834	return skb;
 835}
 836
 837static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
 838	[CTRL_ATTR_FAMILY_ID]	= { .type = NLA_U16 },
 839	[CTRL_ATTR_FAMILY_NAME]	= { .type = NLA_NUL_STRING,
 840				    .len = GENL_NAMSIZ - 1 },
 841};
 842
 843static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 844{
 845	struct sk_buff *msg;
 846	const struct genl_family *res = NULL;
 847	int err = -EINVAL;
 848
 849	if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
 850		u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
 851		res = genl_family_find_byid(id);
 852		err = -ENOENT;
 853	}
 854
 855	if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
 856		char *name;
 857
 858		name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
 859		res = genl_family_find_byname(name);
 860#ifdef CONFIG_MODULES
 861		if (res == NULL) {
 862			genl_unlock();
 863			up_read(&cb_lock);
 864			request_module("net-pf-%d-proto-%d-family-%s",
 865				       PF_NETLINK, NETLINK_GENERIC, name);
 866			down_read(&cb_lock);
 867			genl_lock();
 868			res = genl_family_find_byname(name);
 869		}
 870#endif
 871		err = -ENOENT;
 872	}
 873
 874	if (res == NULL)
 875		return err;
 876
 877	if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
 878		/* family doesn't exist here */
 879		return -ENOENT;
 880	}
 881
 882	msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
 883				    CTRL_CMD_NEWFAMILY);
 884	if (IS_ERR(msg))
 885		return PTR_ERR(msg);
 886
 887	return genlmsg_reply(msg, info);
 888}
 889
 890static int genl_ctrl_event(int event, const struct genl_family *family,
 891			   const struct genl_multicast_group *grp,
 892			   int grp_id)
 893{
 894	struct sk_buff *msg;
 895
 896	/* genl is still initialising */
 897	if (!init_net.genl_sock)
 898		return 0;
 899
 900	switch (event) {
 901	case CTRL_CMD_NEWFAMILY:
 902	case CTRL_CMD_DELFAMILY:
 903		WARN_ON(grp);
 904		msg = ctrl_build_family_msg(family, 0, 0, event);
 905		break;
 906	case CTRL_CMD_NEWMCAST_GRP:
 907	case CTRL_CMD_DELMCAST_GRP:
 908		BUG_ON(!grp);
 909		msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
 910		break;
 911	default:
 912		return -EINVAL;
 913	}
 914
 915	if (IS_ERR(msg))
 916		return PTR_ERR(msg);
 917
 918	if (!family->netnsok) {
 919		genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
 920					0, GFP_KERNEL);
 921	} else {
 922		rcu_read_lock();
 923		genlmsg_multicast_allns(&genl_ctrl, msg, 0,
 924					0, GFP_ATOMIC);
 925		rcu_read_unlock();
 926	}
 927
 928	return 0;
 929}
 930
 931static const struct genl_ops genl_ctrl_ops[] = {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 932	{
 933		.cmd		= CTRL_CMD_GETFAMILY,
 
 
 
 934		.doit		= ctrl_getfamily,
 
 
 
 
 
 
 
 935		.dumpit		= ctrl_dumpfamily,
 936		.policy		= ctrl_policy,
 
 
 
 
 
 
 
 
 
 937	},
 938};
 939
 940static const struct genl_multicast_group genl_ctrl_groups[] = {
 941	{ .name = "notify", },
 942};
 943
 944static struct genl_family genl_ctrl __ro_after_init = {
 945	.module = THIS_MODULE,
 946	.ops = genl_ctrl_ops,
 947	.n_ops = ARRAY_SIZE(genl_ctrl_ops),
 
 948	.mcgrps = genl_ctrl_groups,
 949	.n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
 950	.id = GENL_ID_CTRL,
 951	.name = "nlctrl",
 952	.version = 0x2,
 953	.maxattr = CTRL_ATTR_MAX,
 954	.netnsok = true,
 955};
 956
 957static int genl_bind(struct net *net, int group)
 958{
 959	struct genl_family *f;
 960	int err = -ENOENT;
 961	unsigned int id;
 
 962
 963	down_read(&cb_lock);
 964
 965	idr_for_each_entry(&genl_fam_idr, f, id) {
 966		if (group >= f->mcgrp_offset &&
 967		    group < f->mcgrp_offset + f->n_mcgrps) {
 968			int fam_grp = group - f->mcgrp_offset;
 969
 970			if (!f->netnsok && net != &init_net)
 971				err = -ENOENT;
 972			else if (f->mcast_bind)
 973				err = f->mcast_bind(net, fam_grp);
 974			else
 975				err = 0;
 976			break;
 977		}
 978	}
 979	up_read(&cb_lock);
 980
 981	return err;
 982}
 983
 984static void genl_unbind(struct net *net, int group)
 985{
 986	struct genl_family *f;
 987	unsigned int id;
 988
 989	down_read(&cb_lock);
 
 
 990
 991	idr_for_each_entry(&genl_fam_idr, f, id) {
 992		if (group >= f->mcgrp_offset &&
 993		    group < f->mcgrp_offset + f->n_mcgrps) {
 994			int fam_grp = group - f->mcgrp_offset;
 995
 996			if (f->mcast_unbind)
 997				f->mcast_unbind(net, fam_grp);
 998			break;
 999		}
1000	}
 
1001	up_read(&cb_lock);
 
1002}
1003
1004static int __net_init genl_pernet_init(struct net *net)
1005{
1006	struct netlink_kernel_cfg cfg = {
1007		.input		= genl_rcv,
1008		.flags		= NL_CFG_F_NONROOT_RECV,
1009		.bind		= genl_bind,
1010		.unbind		= genl_unbind,
1011	};
1012
1013	/* we'll bump the group number right afterwards */
1014	net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1015
1016	if (!net->genl_sock && net_eq(net, &init_net))
1017		panic("GENL: Cannot initialize generic netlink\n");
1018
1019	if (!net->genl_sock)
1020		return -ENOMEM;
1021
1022	return 0;
1023}
1024
1025static void __net_exit genl_pernet_exit(struct net *net)
1026{
1027	netlink_kernel_release(net->genl_sock);
1028	net->genl_sock = NULL;
1029}
1030
1031static struct pernet_operations genl_pernet_ops = {
1032	.init = genl_pernet_init,
1033	.exit = genl_pernet_exit,
1034};
1035
1036static int __init genl_init(void)
1037{
1038	int err;
1039
1040	err = genl_register_family(&genl_ctrl);
1041	if (err < 0)
1042		goto problem;
1043
1044	err = register_pernet_subsys(&genl_pernet_ops);
1045	if (err)
1046		goto problem;
1047
1048	return 0;
1049
1050problem:
1051	panic("GENL: Cannot register controller: %d\n", err);
1052}
1053
1054subsys_initcall(genl_init);
1055
1056/**
1057 * genl_family_attrbuf - return family's attrbuf
1058 * @family: the family
1059 *
1060 * Return the family's attrbuf, while validating that it's
1061 * actually valid to access it.
1062 *
1063 * You cannot use this function with a family that has parallel_ops
1064 * and you can only use it within (pre/post) doit/dumpit callbacks.
1065 */
1066struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1067{
1068	if (!WARN_ON(family->parallel_ops))
1069		lockdep_assert_held(&genl_mutex);
1070
1071	return family->attrbuf;
1072}
1073EXPORT_SYMBOL(genl_family_attrbuf);
1074
1075static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1076			 gfp_t flags)
1077{
1078	struct sk_buff *tmp;
1079	struct net *net, *prev = NULL;
 
1080	int err;
1081
1082	for_each_net_rcu(net) {
1083		if (prev) {
1084			tmp = skb_clone(skb, flags);
1085			if (!tmp) {
1086				err = -ENOMEM;
1087				goto error;
1088			}
1089			err = nlmsg_multicast(prev->genl_sock, tmp,
1090					      portid, group, flags);
1091			if (err)
 
 
1092				goto error;
1093		}
1094
1095		prev = net;
1096	}
1097
1098	return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
 
 
 
 
 
1099 error:
1100	kfree_skb(skb);
1101	return err;
1102}
1103
1104int genlmsg_multicast_allns(const struct genl_family *family,
1105			    struct sk_buff *skb, u32 portid,
1106			    unsigned int group, gfp_t flags)
1107{
1108	if (WARN_ON_ONCE(group >= family->n_mcgrps))
1109		return -EINVAL;
 
1110	group = family->mcgrp_offset + group;
1111	return genlmsg_mcast(skb, portid, group, flags);
1112}
1113EXPORT_SYMBOL(genlmsg_multicast_allns);
1114
1115void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1116		 struct genl_info *info, u32 group, gfp_t flags)
1117{
1118	struct net *net = genl_info_net(info);
1119	struct sock *sk = net->genl_sock;
1120	int report = 0;
1121
1122	if (info->nlhdr)
1123		report = nlmsg_report(info->nlhdr);
1124
1125	if (WARN_ON_ONCE(group >= family->n_mcgrps))
1126		return;
 
1127	group = family->mcgrp_offset + group;
1128	nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
 
1129}
1130EXPORT_SYMBOL(genl_notify);