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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
25static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26static DECLARE_RWSEM(cb_lock);
27
28atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31void genl_lock(void)
32{
33 mutex_lock(&genl_mutex);
34}
35EXPORT_SYMBOL(genl_lock);
36
37void genl_unlock(void)
38{
39 mutex_unlock(&genl_mutex);
40}
41EXPORT_SYMBOL(genl_unlock);
42
43#ifdef CONFIG_LOCKDEP
44bool lockdep_genl_is_held(void)
45{
46 return lockdep_is_held(&genl_mutex);
47}
48EXPORT_SYMBOL(lockdep_genl_is_held);
49#endif
50
51static void genl_lock_all(void)
52{
53 down_write(&cb_lock);
54 genl_lock();
55}
56
57static void genl_unlock_all(void)
58{
59 genl_unlock();
60 up_write(&cb_lock);
61}
62
63static 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 */
83static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86static unsigned long *mc_groups = &mc_group_start;
87static unsigned long mc_groups_longs = 1;
88
89static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static const struct genl_family *genl_family_find_byid(unsigned int id)
94{
95 return idr_find(&genl_fam_idr, id);
96}
97
98static 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
110static int genl_get_cmd_cnt(const struct genl_family *family)
111{
112 return family->n_ops + family->n_small_ops;
113}
114
115static 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
126static 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
140static 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
155static 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
169static 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
177static 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
189static 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
249static struct genl_family genl_ctrl;
250
251static 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
329static 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
354static 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 */
392int 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
445errout_remove:
446 idr_remove(&genl_fam_idr, family->id);
447errout_locked:
448 genl_unlock_all();
449 return err;
450}
451EXPORT_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 */
461int 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}
483EXPORT_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 */
496void *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}
514EXPORT_SYMBOL(genlmsg_put);
515
516static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
517{
518 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
519}
520
521static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
522{
523 kfree(info);
524}
525
526static struct nlattr **
527genl_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
557static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
558{
559 kfree(attrbuf);
560}
561
562struct 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
570static 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
590no_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
617static 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
628static 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
644static 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
657static 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
703static 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
744out:
745 genl_family_rcv_msg_attrs_free(attrbuf);
746
747 return err;
748}
749
750static 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
787static 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
808static 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
819static struct genl_family genl_ctrl;
820
821static 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
905nla_put_failure:
906 genlmsg_cancel(skb, hdr);
907 return -EMSGSIZE;
908}
909
910static 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
946nla_put_failure:
947 genlmsg_cancel(skb, hdr);
948 return -EMSGSIZE;
949}
950
951static 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
978static 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
997static struct sk_buff *
998ctrl_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
1019static 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
1025static 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
1072static 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
1113struct 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
1123static 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
1130static 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
1194static 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
1212static 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;
1257err:
1258 genlmsg_cancel(skb, hdr);
1259 return -ENOBUFS;
1260}
1261
1262static 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
1315nla_put_failure:
1316 genlmsg_cancel(skb, hdr);
1317 return skb->len;
1318}
1319
1320static 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
1328static 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
1347static const struct genl_multicast_group genl_ctrl_groups[] = {
1348 { .name = "notify", },
1349};
1350
1351static 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
1363static 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
1394static 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
1414static void __net_exit genl_pernet_exit(struct net *net)
1415{
1416 netlink_kernel_release(net->genl_sock);
1417 net->genl_sock = NULL;
1418}
1419
1420static struct pernet_operations genl_pernet_ops = {
1421 .init = genl_pernet_init,
1422 .exit = genl_pernet_exit,
1423};
1424
1425static 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
1439problem:
1440 panic("GENL: Cannot register controller: %d\n", err);
1441}
1442
1443core_initcall(genl_init);
1444
1445static 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
1482int 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}
1491EXPORT_SYMBOL(genlmsg_multicast_allns);
1492
1493void 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}
1508EXPORT_SYMBOL(genl_notify);
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
25static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26static DECLARE_RWSEM(cb_lock);
27
28atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31void genl_lock(void)
32{
33 mutex_lock(&genl_mutex);
34}
35EXPORT_SYMBOL(genl_lock);
36
37void genl_unlock(void)
38{
39 mutex_unlock(&genl_mutex);
40}
41EXPORT_SYMBOL(genl_unlock);
42
43#ifdef CONFIG_LOCKDEP
44bool lockdep_genl_is_held(void)
45{
46 return lockdep_is_held(&genl_mutex);
47}
48EXPORT_SYMBOL(lockdep_genl_is_held);
49#endif
50
51static void genl_lock_all(void)
52{
53 down_write(&cb_lock);
54 genl_lock();
55}
56
57static void genl_unlock_all(void)
58{
59 genl_unlock();
60 up_write(&cb_lock);
61}
62
63static 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 */
83static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86static unsigned long *mc_groups = &mc_group_start;
87static unsigned long mc_groups_longs = 1;
88
89static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static const struct genl_family *genl_family_find_byid(unsigned int id)
94{
95 return idr_find(&genl_fam_idr, id);
96}
97
98static 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
110static const struct genl_ops *genl_get_cmd(u8 cmd,
111 const struct genl_family *family)
112{
113 int i;
114
115 for (i = 0; i < family->n_ops; i++)
116 if (family->ops[i].cmd == cmd)
117 return &family->ops[i];
118
119 return NULL;
120}
121
122static int genl_allocate_reserve_groups(int n_groups, int *first_id)
123{
124 unsigned long *new_groups;
125 int start = 0;
126 int i;
127 int id;
128 bool fits;
129
130 do {
131 if (start == 0)
132 id = find_first_zero_bit(mc_groups,
133 mc_groups_longs *
134 BITS_PER_LONG);
135 else
136 id = find_next_zero_bit(mc_groups,
137 mc_groups_longs * BITS_PER_LONG,
138 start);
139
140 fits = true;
141 for (i = id;
142 i < min_t(int, id + n_groups,
143 mc_groups_longs * BITS_PER_LONG);
144 i++) {
145 if (test_bit(i, mc_groups)) {
146 start = i;
147 fits = false;
148 break;
149 }
150 }
151
152 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
153 unsigned long new_longs = mc_groups_longs +
154 BITS_TO_LONGS(n_groups);
155 size_t nlen = new_longs * sizeof(unsigned long);
156
157 if (mc_groups == &mc_group_start) {
158 new_groups = kzalloc(nlen, GFP_KERNEL);
159 if (!new_groups)
160 return -ENOMEM;
161 mc_groups = new_groups;
162 *mc_groups = mc_group_start;
163 } else {
164 new_groups = krealloc(mc_groups, nlen,
165 GFP_KERNEL);
166 if (!new_groups)
167 return -ENOMEM;
168 mc_groups = new_groups;
169 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
170 mc_groups[mc_groups_longs + i] = 0;
171 }
172 mc_groups_longs = new_longs;
173 }
174 } while (!fits);
175
176 for (i = id; i < id + n_groups; i++)
177 set_bit(i, mc_groups);
178 *first_id = id;
179 return 0;
180}
181
182static struct genl_family genl_ctrl;
183
184static int genl_validate_assign_mc_groups(struct genl_family *family)
185{
186 int first_id;
187 int n_groups = family->n_mcgrps;
188 int err = 0, i;
189 bool groups_allocated = false;
190
191 if (!n_groups)
192 return 0;
193
194 for (i = 0; i < n_groups; i++) {
195 const struct genl_multicast_group *grp = &family->mcgrps[i];
196
197 if (WARN_ON(grp->name[0] == '\0'))
198 return -EINVAL;
199 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
200 return -EINVAL;
201 }
202
203 /* special-case our own group and hacks */
204 if (family == &genl_ctrl) {
205 first_id = GENL_ID_CTRL;
206 BUG_ON(n_groups != 1);
207 } else if (strcmp(family->name, "NET_DM") == 0) {
208 first_id = 1;
209 BUG_ON(n_groups != 1);
210 } else if (family->id == GENL_ID_VFS_DQUOT) {
211 first_id = GENL_ID_VFS_DQUOT;
212 BUG_ON(n_groups != 1);
213 } else if (family->id == GENL_ID_PMCRAID) {
214 first_id = GENL_ID_PMCRAID;
215 BUG_ON(n_groups != 1);
216 } else {
217 groups_allocated = true;
218 err = genl_allocate_reserve_groups(n_groups, &first_id);
219 if (err)
220 return err;
221 }
222
223 family->mcgrp_offset = first_id;
224
225 /* if still initializing, can't and don't need to to realloc bitmaps */
226 if (!init_net.genl_sock)
227 return 0;
228
229 if (family->netnsok) {
230 struct net *net;
231
232 netlink_table_grab();
233 rcu_read_lock();
234 for_each_net_rcu(net) {
235 err = __netlink_change_ngroups(net->genl_sock,
236 mc_groups_longs * BITS_PER_LONG);
237 if (err) {
238 /*
239 * No need to roll back, can only fail if
240 * memory allocation fails and then the
241 * number of _possible_ groups has been
242 * increased on some sockets which is ok.
243 */
244 break;
245 }
246 }
247 rcu_read_unlock();
248 netlink_table_ungrab();
249 } else {
250 err = netlink_change_ngroups(init_net.genl_sock,
251 mc_groups_longs * BITS_PER_LONG);
252 }
253
254 if (groups_allocated && err) {
255 for (i = 0; i < family->n_mcgrps; i++)
256 clear_bit(family->mcgrp_offset + i, mc_groups);
257 }
258
259 return err;
260}
261
262static void genl_unregister_mc_groups(const struct genl_family *family)
263{
264 struct net *net;
265 int i;
266
267 netlink_table_grab();
268 rcu_read_lock();
269 for_each_net_rcu(net) {
270 for (i = 0; i < family->n_mcgrps; i++)
271 __netlink_clear_multicast_users(
272 net->genl_sock, family->mcgrp_offset + i);
273 }
274 rcu_read_unlock();
275 netlink_table_ungrab();
276
277 for (i = 0; i < family->n_mcgrps; i++) {
278 int grp_id = family->mcgrp_offset + i;
279
280 if (grp_id != 1)
281 clear_bit(grp_id, mc_groups);
282 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
283 &family->mcgrps[i], grp_id);
284 }
285}
286
287static int genl_validate_ops(const struct genl_family *family)
288{
289 const struct genl_ops *ops = family->ops;
290 unsigned int n_ops = family->n_ops;
291 int i, j;
292
293 if (WARN_ON(n_ops && !ops))
294 return -EINVAL;
295
296 if (!n_ops)
297 return 0;
298
299 for (i = 0; i < n_ops; i++) {
300 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
301 return -EINVAL;
302 for (j = i + 1; j < n_ops; j++)
303 if (ops[i].cmd == ops[j].cmd)
304 return -EINVAL;
305 }
306
307 return 0;
308}
309
310/**
311 * genl_register_family - register a generic netlink family
312 * @family: generic netlink family
313 *
314 * Registers the specified family after validating it first. Only one
315 * family may be registered with the same family name or identifier.
316 *
317 * The family's ops, multicast groups and module pointer must already
318 * be assigned.
319 *
320 * Return 0 on success or a negative error code.
321 */
322int genl_register_family(struct genl_family *family)
323{
324 int err, i;
325 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
326
327 err = genl_validate_ops(family);
328 if (err)
329 return err;
330
331 genl_lock_all();
332
333 if (genl_family_find_byname(family->name)) {
334 err = -EEXIST;
335 goto errout_locked;
336 }
337
338 /*
339 * Sadly, a few cases need to be special-cased
340 * due to them having previously abused the API
341 * and having used their family ID also as their
342 * multicast group ID, so we use reserved IDs
343 * for both to be sure we can do that mapping.
344 */
345 if (family == &genl_ctrl) {
346 /* and this needs to be special for initial family lookups */
347 start = end = GENL_ID_CTRL;
348 } else if (strcmp(family->name, "pmcraid") == 0) {
349 start = end = GENL_ID_PMCRAID;
350 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
351 start = end = GENL_ID_VFS_DQUOT;
352 }
353
354 if (family->maxattr && !family->parallel_ops) {
355 family->attrbuf = kmalloc((family->maxattr+1) *
356 sizeof(struct nlattr *), GFP_KERNEL);
357 if (family->attrbuf == NULL) {
358 err = -ENOMEM;
359 goto errout_locked;
360 }
361 } else
362 family->attrbuf = NULL;
363
364 family->id = idr_alloc(&genl_fam_idr, family,
365 start, end + 1, GFP_KERNEL);
366 if (family->id < 0) {
367 err = family->id;
368 goto errout_locked;
369 }
370
371 err = genl_validate_assign_mc_groups(family);
372 if (err)
373 goto errout_remove;
374
375 genl_unlock_all();
376
377 /* send all events */
378 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
379 for (i = 0; i < family->n_mcgrps; i++)
380 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
381 &family->mcgrps[i], family->mcgrp_offset + i);
382
383 return 0;
384
385errout_remove:
386 idr_remove(&genl_fam_idr, family->id);
387 kfree(family->attrbuf);
388errout_locked:
389 genl_unlock_all();
390 return err;
391}
392EXPORT_SYMBOL(genl_register_family);
393
394/**
395 * genl_unregister_family - unregister generic netlink family
396 * @family: generic netlink family
397 *
398 * Unregisters the specified family.
399 *
400 * Returns 0 on success or a negative error code.
401 */
402int genl_unregister_family(const struct genl_family *family)
403{
404 genl_lock_all();
405
406 if (!genl_family_find_byid(family->id)) {
407 genl_unlock_all();
408 return -ENOENT;
409 }
410
411 genl_unregister_mc_groups(family);
412
413 idr_remove(&genl_fam_idr, family->id);
414
415 up_write(&cb_lock);
416 wait_event(genl_sk_destructing_waitq,
417 atomic_read(&genl_sk_destructing_cnt) == 0);
418 genl_unlock();
419
420 kfree(family->attrbuf);
421
422 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
423
424 return 0;
425}
426EXPORT_SYMBOL(genl_unregister_family);
427
428/**
429 * genlmsg_put - Add generic netlink header to netlink message
430 * @skb: socket buffer holding the message
431 * @portid: netlink portid the message is addressed to
432 * @seq: sequence number (usually the one of the sender)
433 * @family: generic netlink family
434 * @flags: netlink message flags
435 * @cmd: generic netlink command
436 *
437 * Returns pointer to user specific header
438 */
439void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
440 const struct genl_family *family, int flags, u8 cmd)
441{
442 struct nlmsghdr *nlh;
443 struct genlmsghdr *hdr;
444
445 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
446 family->hdrsize, flags);
447 if (nlh == NULL)
448 return NULL;
449
450 hdr = nlmsg_data(nlh);
451 hdr->cmd = cmd;
452 hdr->version = family->version;
453 hdr->reserved = 0;
454
455 return (char *) hdr + GENL_HDRLEN;
456}
457EXPORT_SYMBOL(genlmsg_put);
458
459static int genl_lock_start(struct netlink_callback *cb)
460{
461 /* our ops are always const - netlink API doesn't propagate that */
462 const struct genl_ops *ops = cb->data;
463 int rc = 0;
464
465 if (ops->start) {
466 genl_lock();
467 rc = ops->start(cb);
468 genl_unlock();
469 }
470 return rc;
471}
472
473static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
474{
475 /* our ops are always const - netlink API doesn't propagate that */
476 const struct genl_ops *ops = cb->data;
477 int rc;
478
479 genl_lock();
480 rc = ops->dumpit(skb, cb);
481 genl_unlock();
482 return rc;
483}
484
485static int genl_lock_done(struct netlink_callback *cb)
486{
487 /* our ops are always const - netlink API doesn't propagate that */
488 const struct genl_ops *ops = cb->data;
489 int rc = 0;
490
491 if (ops->done) {
492 genl_lock();
493 rc = ops->done(cb);
494 genl_unlock();
495 }
496 return rc;
497}
498
499static int genl_family_rcv_msg(const struct genl_family *family,
500 struct sk_buff *skb,
501 struct nlmsghdr *nlh,
502 struct netlink_ext_ack *extack)
503{
504 const struct genl_ops *ops;
505 struct net *net = sock_net(skb->sk);
506 struct genl_info info;
507 struct genlmsghdr *hdr = nlmsg_data(nlh);
508 struct nlattr **attrbuf;
509 int hdrlen, err;
510
511 /* this family doesn't exist in this netns */
512 if (!family->netnsok && !net_eq(net, &init_net))
513 return -ENOENT;
514
515 hdrlen = GENL_HDRLEN + family->hdrsize;
516 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
517 return -EINVAL;
518
519 ops = genl_get_cmd(hdr->cmd, family);
520 if (ops == NULL)
521 return -EOPNOTSUPP;
522
523 if ((ops->flags & GENL_ADMIN_PERM) &&
524 !netlink_capable(skb, CAP_NET_ADMIN))
525 return -EPERM;
526
527 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
528 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
529 return -EPERM;
530
531 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
532 int rc;
533
534 if (ops->dumpit == NULL)
535 return -EOPNOTSUPP;
536
537 if (!family->parallel_ops) {
538 struct netlink_dump_control c = {
539 .module = family->module,
540 /* we have const, but the netlink API doesn't */
541 .data = (void *)ops,
542 .start = genl_lock_start,
543 .dump = genl_lock_dumpit,
544 .done = genl_lock_done,
545 };
546
547 genl_unlock();
548 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
549 genl_lock();
550
551 } else {
552 struct netlink_dump_control c = {
553 .module = family->module,
554 .start = ops->start,
555 .dump = ops->dumpit,
556 .done = ops->done,
557 };
558
559 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
560 }
561
562 return rc;
563 }
564
565 if (ops->doit == NULL)
566 return -EOPNOTSUPP;
567
568 if (family->maxattr && family->parallel_ops) {
569 attrbuf = kmalloc((family->maxattr+1) *
570 sizeof(struct nlattr *), GFP_KERNEL);
571 if (attrbuf == NULL)
572 return -ENOMEM;
573 } else
574 attrbuf = family->attrbuf;
575
576 if (attrbuf) {
577 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
578 ops->policy, extack);
579 if (err < 0)
580 goto out;
581 }
582
583 info.snd_seq = nlh->nlmsg_seq;
584 info.snd_portid = NETLINK_CB(skb).portid;
585 info.nlhdr = nlh;
586 info.genlhdr = nlmsg_data(nlh);
587 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
588 info.attrs = attrbuf;
589 info.extack = extack;
590 genl_info_net_set(&info, net);
591 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
592
593 if (family->pre_doit) {
594 err = family->pre_doit(ops, skb, &info);
595 if (err)
596 goto out;
597 }
598
599 err = ops->doit(skb, &info);
600
601 if (family->post_doit)
602 family->post_doit(ops, skb, &info);
603
604out:
605 if (family->parallel_ops)
606 kfree(attrbuf);
607
608 return err;
609}
610
611static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
612 struct netlink_ext_ack *extack)
613{
614 const struct genl_family *family;
615 int err;
616
617 family = genl_family_find_byid(nlh->nlmsg_type);
618 if (family == NULL)
619 return -ENOENT;
620
621 if (!family->parallel_ops)
622 genl_lock();
623
624 err = genl_family_rcv_msg(family, skb, nlh, extack);
625
626 if (!family->parallel_ops)
627 genl_unlock();
628
629 return err;
630}
631
632static void genl_rcv(struct sk_buff *skb)
633{
634 down_read(&cb_lock);
635 netlink_rcv_skb(skb, &genl_rcv_msg);
636 up_read(&cb_lock);
637}
638
639/**************************************************************************
640 * Controller
641 **************************************************************************/
642
643static struct genl_family genl_ctrl;
644
645static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
646 u32 flags, struct sk_buff *skb, u8 cmd)
647{
648 void *hdr;
649
650 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
651 if (hdr == NULL)
652 return -1;
653
654 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
655 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
656 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
657 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
658 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
659 goto nla_put_failure;
660
661 if (family->n_ops) {
662 struct nlattr *nla_ops;
663 int i;
664
665 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
666 if (nla_ops == NULL)
667 goto nla_put_failure;
668
669 for (i = 0; i < family->n_ops; i++) {
670 struct nlattr *nest;
671 const struct genl_ops *ops = &family->ops[i];
672 u32 op_flags = ops->flags;
673
674 if (ops->dumpit)
675 op_flags |= GENL_CMD_CAP_DUMP;
676 if (ops->doit)
677 op_flags |= GENL_CMD_CAP_DO;
678 if (ops->policy)
679 op_flags |= GENL_CMD_CAP_HASPOL;
680
681 nest = nla_nest_start(skb, i + 1);
682 if (nest == NULL)
683 goto nla_put_failure;
684
685 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
686 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
687 goto nla_put_failure;
688
689 nla_nest_end(skb, nest);
690 }
691
692 nla_nest_end(skb, nla_ops);
693 }
694
695 if (family->n_mcgrps) {
696 struct nlattr *nla_grps;
697 int i;
698
699 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
700 if (nla_grps == NULL)
701 goto nla_put_failure;
702
703 for (i = 0; i < family->n_mcgrps; i++) {
704 struct nlattr *nest;
705 const struct genl_multicast_group *grp;
706
707 grp = &family->mcgrps[i];
708
709 nest = nla_nest_start(skb, i + 1);
710 if (nest == NULL)
711 goto nla_put_failure;
712
713 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
714 family->mcgrp_offset + i) ||
715 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
716 grp->name))
717 goto nla_put_failure;
718
719 nla_nest_end(skb, nest);
720 }
721 nla_nest_end(skb, nla_grps);
722 }
723
724 genlmsg_end(skb, hdr);
725 return 0;
726
727nla_put_failure:
728 genlmsg_cancel(skb, hdr);
729 return -EMSGSIZE;
730}
731
732static int ctrl_fill_mcgrp_info(const struct genl_family *family,
733 const struct genl_multicast_group *grp,
734 int grp_id, u32 portid, u32 seq, u32 flags,
735 struct sk_buff *skb, u8 cmd)
736{
737 void *hdr;
738 struct nlattr *nla_grps;
739 struct nlattr *nest;
740
741 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
742 if (hdr == NULL)
743 return -1;
744
745 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
746 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
747 goto nla_put_failure;
748
749 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
750 if (nla_grps == NULL)
751 goto nla_put_failure;
752
753 nest = nla_nest_start(skb, 1);
754 if (nest == NULL)
755 goto nla_put_failure;
756
757 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
758 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
759 grp->name))
760 goto nla_put_failure;
761
762 nla_nest_end(skb, nest);
763 nla_nest_end(skb, nla_grps);
764
765 genlmsg_end(skb, hdr);
766 return 0;
767
768nla_put_failure:
769 genlmsg_cancel(skb, hdr);
770 return -EMSGSIZE;
771}
772
773static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
774{
775 int n = 0;
776 struct genl_family *rt;
777 struct net *net = sock_net(skb->sk);
778 int fams_to_skip = cb->args[0];
779 unsigned int id;
780
781 idr_for_each_entry(&genl_fam_idr, rt, id) {
782 if (!rt->netnsok && !net_eq(net, &init_net))
783 continue;
784
785 if (n++ < fams_to_skip)
786 continue;
787
788 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
789 cb->nlh->nlmsg_seq, NLM_F_MULTI,
790 skb, CTRL_CMD_NEWFAMILY) < 0) {
791 n--;
792 break;
793 }
794 }
795
796 cb->args[0] = n;
797 return skb->len;
798}
799
800static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
801 u32 portid, int seq, u8 cmd)
802{
803 struct sk_buff *skb;
804 int err;
805
806 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
807 if (skb == NULL)
808 return ERR_PTR(-ENOBUFS);
809
810 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
811 if (err < 0) {
812 nlmsg_free(skb);
813 return ERR_PTR(err);
814 }
815
816 return skb;
817}
818
819static struct sk_buff *
820ctrl_build_mcgrp_msg(const struct genl_family *family,
821 const struct genl_multicast_group *grp,
822 int grp_id, u32 portid, int seq, u8 cmd)
823{
824 struct sk_buff *skb;
825 int err;
826
827 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
828 if (skb == NULL)
829 return ERR_PTR(-ENOBUFS);
830
831 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
832 seq, 0, skb, cmd);
833 if (err < 0) {
834 nlmsg_free(skb);
835 return ERR_PTR(err);
836 }
837
838 return skb;
839}
840
841static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
842 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
843 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
844 .len = GENL_NAMSIZ - 1 },
845};
846
847static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
848{
849 struct sk_buff *msg;
850 const struct genl_family *res = NULL;
851 int err = -EINVAL;
852
853 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
854 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
855 res = genl_family_find_byid(id);
856 err = -ENOENT;
857 }
858
859 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
860 char *name;
861
862 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
863 res = genl_family_find_byname(name);
864#ifdef CONFIG_MODULES
865 if (res == NULL) {
866 genl_unlock();
867 up_read(&cb_lock);
868 request_module("net-pf-%d-proto-%d-family-%s",
869 PF_NETLINK, NETLINK_GENERIC, name);
870 down_read(&cb_lock);
871 genl_lock();
872 res = genl_family_find_byname(name);
873 }
874#endif
875 err = -ENOENT;
876 }
877
878 if (res == NULL)
879 return err;
880
881 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
882 /* family doesn't exist here */
883 return -ENOENT;
884 }
885
886 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
887 CTRL_CMD_NEWFAMILY);
888 if (IS_ERR(msg))
889 return PTR_ERR(msg);
890
891 return genlmsg_reply(msg, info);
892}
893
894static int genl_ctrl_event(int event, const struct genl_family *family,
895 const struct genl_multicast_group *grp,
896 int grp_id)
897{
898 struct sk_buff *msg;
899
900 /* genl is still initialising */
901 if (!init_net.genl_sock)
902 return 0;
903
904 switch (event) {
905 case CTRL_CMD_NEWFAMILY:
906 case CTRL_CMD_DELFAMILY:
907 WARN_ON(grp);
908 msg = ctrl_build_family_msg(family, 0, 0, event);
909 break;
910 case CTRL_CMD_NEWMCAST_GRP:
911 case CTRL_CMD_DELMCAST_GRP:
912 BUG_ON(!grp);
913 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
914 break;
915 default:
916 return -EINVAL;
917 }
918
919 if (IS_ERR(msg))
920 return PTR_ERR(msg);
921
922 if (!family->netnsok) {
923 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
924 0, GFP_KERNEL);
925 } else {
926 rcu_read_lock();
927 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
928 0, GFP_ATOMIC);
929 rcu_read_unlock();
930 }
931
932 return 0;
933}
934
935static const struct genl_ops genl_ctrl_ops[] = {
936 {
937 .cmd = CTRL_CMD_GETFAMILY,
938 .doit = ctrl_getfamily,
939 .dumpit = ctrl_dumpfamily,
940 .policy = ctrl_policy,
941 },
942};
943
944static const struct genl_multicast_group genl_ctrl_groups[] = {
945 { .name = "notify", },
946};
947
948static struct genl_family genl_ctrl __ro_after_init = {
949 .module = THIS_MODULE,
950 .ops = genl_ctrl_ops,
951 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
952 .mcgrps = genl_ctrl_groups,
953 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
954 .id = GENL_ID_CTRL,
955 .name = "nlctrl",
956 .version = 0x2,
957 .maxattr = CTRL_ATTR_MAX,
958 .netnsok = true,
959};
960
961static int genl_bind(struct net *net, int group)
962{
963 struct genl_family *f;
964 int err = -ENOENT;
965 unsigned int id;
966
967 down_read(&cb_lock);
968
969 idr_for_each_entry(&genl_fam_idr, f, id) {
970 if (group >= f->mcgrp_offset &&
971 group < f->mcgrp_offset + f->n_mcgrps) {
972 int fam_grp = group - f->mcgrp_offset;
973
974 if (!f->netnsok && net != &init_net)
975 err = -ENOENT;
976 else if (f->mcast_bind)
977 err = f->mcast_bind(net, fam_grp);
978 else
979 err = 0;
980 break;
981 }
982 }
983 up_read(&cb_lock);
984
985 return err;
986}
987
988static void genl_unbind(struct net *net, int group)
989{
990 struct genl_family *f;
991 unsigned int id;
992
993 down_read(&cb_lock);
994
995 idr_for_each_entry(&genl_fam_idr, f, id) {
996 if (group >= f->mcgrp_offset &&
997 group < f->mcgrp_offset + f->n_mcgrps) {
998 int fam_grp = group - f->mcgrp_offset;
999
1000 if (f->mcast_unbind)
1001 f->mcast_unbind(net, fam_grp);
1002 break;
1003 }
1004 }
1005 up_read(&cb_lock);
1006}
1007
1008static int __net_init genl_pernet_init(struct net *net)
1009{
1010 struct netlink_kernel_cfg cfg = {
1011 .input = genl_rcv,
1012 .flags = NL_CFG_F_NONROOT_RECV,
1013 .bind = genl_bind,
1014 .unbind = genl_unbind,
1015 };
1016
1017 /* we'll bump the group number right afterwards */
1018 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1019
1020 if (!net->genl_sock && net_eq(net, &init_net))
1021 panic("GENL: Cannot initialize generic netlink\n");
1022
1023 if (!net->genl_sock)
1024 return -ENOMEM;
1025
1026 return 0;
1027}
1028
1029static void __net_exit genl_pernet_exit(struct net *net)
1030{
1031 netlink_kernel_release(net->genl_sock);
1032 net->genl_sock = NULL;
1033}
1034
1035static struct pernet_operations genl_pernet_ops = {
1036 .init = genl_pernet_init,
1037 .exit = genl_pernet_exit,
1038};
1039
1040static int __init genl_init(void)
1041{
1042 int err;
1043
1044 err = genl_register_family(&genl_ctrl);
1045 if (err < 0)
1046 goto problem;
1047
1048 err = register_pernet_subsys(&genl_pernet_ops);
1049 if (err)
1050 goto problem;
1051
1052 return 0;
1053
1054problem:
1055 panic("GENL: Cannot register controller: %d\n", err);
1056}
1057
1058subsys_initcall(genl_init);
1059
1060/**
1061 * genl_family_attrbuf - return family's attrbuf
1062 * @family: the family
1063 *
1064 * Return the family's attrbuf, while validating that it's
1065 * actually valid to access it.
1066 *
1067 * You cannot use this function with a family that has parallel_ops
1068 * and you can only use it within (pre/post) doit/dumpit callbacks.
1069 */
1070struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1071{
1072 if (!WARN_ON(family->parallel_ops))
1073 lockdep_assert_held(&genl_mutex);
1074
1075 return family->attrbuf;
1076}
1077EXPORT_SYMBOL(genl_family_attrbuf);
1078
1079static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1080 gfp_t flags)
1081{
1082 struct sk_buff *tmp;
1083 struct net *net, *prev = NULL;
1084 bool delivered = false;
1085 int err;
1086
1087 for_each_net_rcu(net) {
1088 if (prev) {
1089 tmp = skb_clone(skb, flags);
1090 if (!tmp) {
1091 err = -ENOMEM;
1092 goto error;
1093 }
1094 err = nlmsg_multicast(prev->genl_sock, tmp,
1095 portid, group, flags);
1096 if (!err)
1097 delivered = true;
1098 else if (err != -ESRCH)
1099 goto error;
1100 }
1101
1102 prev = net;
1103 }
1104
1105 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1106 if (!err)
1107 delivered = true;
1108 else if (err != -ESRCH)
1109 return err;
1110 return delivered ? 0 : -ESRCH;
1111 error:
1112 kfree_skb(skb);
1113 return err;
1114}
1115
1116int genlmsg_multicast_allns(const struct genl_family *family,
1117 struct sk_buff *skb, u32 portid,
1118 unsigned int group, gfp_t flags)
1119{
1120 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1121 return -EINVAL;
1122 group = family->mcgrp_offset + group;
1123 return genlmsg_mcast(skb, portid, group, flags);
1124}
1125EXPORT_SYMBOL(genlmsg_multicast_allns);
1126
1127void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1128 struct genl_info *info, u32 group, gfp_t flags)
1129{
1130 struct net *net = genl_info_net(info);
1131 struct sock *sk = net->genl_sock;
1132 int report = 0;
1133
1134 if (info->nlhdr)
1135 report = nlmsg_report(info->nlhdr);
1136
1137 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1138 return;
1139 group = family->mcgrp_offset + group;
1140 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1141}
1142EXPORT_SYMBOL(genl_notify);