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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_helpers.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
43static void genl_lock_all(void)
44{
45 down_write(&cb_lock);
46 genl_lock();
47}
48
49static void genl_unlock_all(void)
50{
51 genl_unlock();
52 up_write(&cb_lock);
53}
54
55static void genl_op_lock(const struct genl_family *family)
56{
57 if (!family->parallel_ops)
58 genl_lock();
59}
60
61static void genl_op_unlock(const struct genl_family *family)
62{
63 if (!family->parallel_ops)
64 genl_unlock();
65}
66
67static DEFINE_IDR(genl_fam_idr);
68
69/*
70 * Bitmap of multicast groups that are currently in use.
71 *
72 * To avoid an allocation at boot of just one unsigned long,
73 * declare it global instead.
74 * Bit 0 is marked as already used since group 0 is invalid.
75 * Bit 1 is marked as already used since the drop-monitor code
76 * abuses the API and thinks it can statically use group 1.
77 * That group will typically conflict with other groups that
78 * any proper users use.
79 * Bit 16 is marked as used since it's used for generic netlink
80 * and the code no longer marks pre-reserved IDs as used.
81 * Bit 17 is marked as already used since the VFS quota code
82 * also abused this API and relied on family == group ID, we
83 * cater to that by giving it a static family and group ID.
84 * Bit 18 is marked as already used since the PMCRAID driver
85 * did the same thing as the VFS quota code (maybe copied?)
86 */
87static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
88 BIT(GENL_ID_VFS_DQUOT) |
89 BIT(GENL_ID_PMCRAID);
90static unsigned long *mc_groups = &mc_group_start;
91static unsigned long mc_groups_longs = 1;
92
93/* We need the last attribute with non-zero ID therefore a 2-entry array */
94static struct nla_policy genl_policy_reject_all[] = {
95 { .type = NLA_REJECT },
96 { .type = NLA_REJECT },
97};
98
99static int genl_ctrl_event(int event, const struct genl_family *family,
100 const struct genl_multicast_group *grp,
101 int grp_id);
102
103static void
104genl_op_fill_in_reject_policy(const struct genl_family *family,
105 struct genl_ops *op)
106{
107 BUILD_BUG_ON(ARRAY_SIZE(genl_policy_reject_all) - 1 != 1);
108
109 if (op->policy || op->cmd < family->resv_start_op)
110 return;
111
112 op->policy = genl_policy_reject_all;
113 op->maxattr = 1;
114}
115
116static void
117genl_op_fill_in_reject_policy_split(const struct genl_family *family,
118 struct genl_split_ops *op)
119{
120 if (op->policy)
121 return;
122
123 op->policy = genl_policy_reject_all;
124 op->maxattr = 1;
125}
126
127static const struct genl_family *genl_family_find_byid(unsigned int id)
128{
129 return idr_find(&genl_fam_idr, id);
130}
131
132static const struct genl_family *genl_family_find_byname(char *name)
133{
134 const struct genl_family *family;
135 unsigned int id;
136
137 idr_for_each_entry(&genl_fam_idr, family, id)
138 if (strcmp(family->name, name) == 0)
139 return family;
140
141 return NULL;
142}
143
144struct genl_op_iter {
145 const struct genl_family *family;
146 struct genl_split_ops doit;
147 struct genl_split_ops dumpit;
148 int cmd_idx;
149 int entry_idx;
150 u32 cmd;
151 u8 flags;
152};
153
154static void genl_op_from_full(const struct genl_family *family,
155 unsigned int i, struct genl_ops *op)
156{
157 *op = family->ops[i];
158
159 if (!op->maxattr)
160 op->maxattr = family->maxattr;
161 if (!op->policy)
162 op->policy = family->policy;
163
164 genl_op_fill_in_reject_policy(family, op);
165}
166
167static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
168 struct genl_ops *op)
169{
170 int i;
171
172 for (i = 0; i < family->n_ops; i++)
173 if (family->ops[i].cmd == cmd) {
174 genl_op_from_full(family, i, op);
175 return 0;
176 }
177
178 return -ENOENT;
179}
180
181static void genl_op_from_small(const struct genl_family *family,
182 unsigned int i, struct genl_ops *op)
183{
184 memset(op, 0, sizeof(*op));
185 op->doit = family->small_ops[i].doit;
186 op->dumpit = family->small_ops[i].dumpit;
187 op->cmd = family->small_ops[i].cmd;
188 op->internal_flags = family->small_ops[i].internal_flags;
189 op->flags = family->small_ops[i].flags;
190 op->validate = family->small_ops[i].validate;
191
192 op->maxattr = family->maxattr;
193 op->policy = family->policy;
194
195 genl_op_fill_in_reject_policy(family, op);
196}
197
198static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
199 struct genl_ops *op)
200{
201 int i;
202
203 for (i = 0; i < family->n_small_ops; i++)
204 if (family->small_ops[i].cmd == cmd) {
205 genl_op_from_small(family, i, op);
206 return 0;
207 }
208
209 return -ENOENT;
210}
211
212static void genl_op_from_split(struct genl_op_iter *iter)
213{
214 const struct genl_family *family = iter->family;
215 int i, cnt = 0;
216
217 i = iter->entry_idx - family->n_ops - family->n_small_ops;
218
219 if (family->split_ops[i + cnt].flags & GENL_CMD_CAP_DO) {
220 iter->doit = family->split_ops[i + cnt];
221 genl_op_fill_in_reject_policy_split(family, &iter->doit);
222 cnt++;
223 } else {
224 memset(&iter->doit, 0, sizeof(iter->doit));
225 }
226
227 if (i + cnt < family->n_split_ops &&
228 family->split_ops[i + cnt].flags & GENL_CMD_CAP_DUMP &&
229 (!cnt || family->split_ops[i + cnt].cmd == iter->doit.cmd)) {
230 iter->dumpit = family->split_ops[i + cnt];
231 genl_op_fill_in_reject_policy_split(family, &iter->dumpit);
232 cnt++;
233 } else {
234 memset(&iter->dumpit, 0, sizeof(iter->dumpit));
235 }
236
237 WARN_ON(!cnt);
238 iter->entry_idx += cnt;
239}
240
241static int
242genl_get_cmd_split(u32 cmd, u8 flag, const struct genl_family *family,
243 struct genl_split_ops *op)
244{
245 int i;
246
247 for (i = 0; i < family->n_split_ops; i++)
248 if (family->split_ops[i].cmd == cmd &&
249 family->split_ops[i].flags & flag) {
250 *op = family->split_ops[i];
251 return 0;
252 }
253
254 return -ENOENT;
255}
256
257static int
258genl_cmd_full_to_split(struct genl_split_ops *op,
259 const struct genl_family *family,
260 const struct genl_ops *full, u8 flags)
261{
262 if ((flags & GENL_CMD_CAP_DO && !full->doit) ||
263 (flags & GENL_CMD_CAP_DUMP && !full->dumpit)) {
264 memset(op, 0, sizeof(*op));
265 return -ENOENT;
266 }
267
268 if (flags & GENL_CMD_CAP_DUMP) {
269 op->start = full->start;
270 op->dumpit = full->dumpit;
271 op->done = full->done;
272 } else {
273 op->pre_doit = family->pre_doit;
274 op->doit = full->doit;
275 op->post_doit = family->post_doit;
276 }
277
278 if (flags & GENL_CMD_CAP_DUMP &&
279 full->validate & GENL_DONT_VALIDATE_DUMP) {
280 op->policy = NULL;
281 op->maxattr = 0;
282 } else {
283 op->policy = full->policy;
284 op->maxattr = full->maxattr;
285 }
286
287 op->cmd = full->cmd;
288 op->internal_flags = full->internal_flags;
289 op->flags = full->flags;
290 op->validate = full->validate;
291
292 /* Make sure flags include the GENL_CMD_CAP_DO / GENL_CMD_CAP_DUMP */
293 op->flags |= flags;
294
295 return 0;
296}
297
298/* Must make sure that op is initialized to 0 on failure */
299static int
300genl_get_cmd(u32 cmd, u8 flags, const struct genl_family *family,
301 struct genl_split_ops *op)
302{
303 struct genl_ops full;
304 int err;
305
306 err = genl_get_cmd_full(cmd, family, &full);
307 if (err == -ENOENT)
308 err = genl_get_cmd_small(cmd, family, &full);
309 /* Found one of legacy forms */
310 if (err == 0)
311 return genl_cmd_full_to_split(op, family, &full, flags);
312
313 err = genl_get_cmd_split(cmd, flags, family, op);
314 if (err)
315 memset(op, 0, sizeof(*op));
316 return err;
317}
318
319/* For policy dumping only, get ops of both do and dump.
320 * Fail if both are missing, genl_get_cmd() will zero-init in case of failure.
321 */
322static int
323genl_get_cmd_both(u32 cmd, const struct genl_family *family,
324 struct genl_split_ops *doit, struct genl_split_ops *dumpit)
325{
326 int err1, err2;
327
328 err1 = genl_get_cmd(cmd, GENL_CMD_CAP_DO, family, doit);
329 err2 = genl_get_cmd(cmd, GENL_CMD_CAP_DUMP, family, dumpit);
330
331 return err1 && err2 ? -ENOENT : 0;
332}
333
334static bool
335genl_op_iter_init(const struct genl_family *family, struct genl_op_iter *iter)
336{
337 iter->family = family;
338 iter->cmd_idx = 0;
339 iter->entry_idx = 0;
340
341 iter->flags = 0;
342
343 return iter->family->n_ops +
344 iter->family->n_small_ops +
345 iter->family->n_split_ops;
346}
347
348static bool genl_op_iter_next(struct genl_op_iter *iter)
349{
350 const struct genl_family *family = iter->family;
351 bool legacy_op = true;
352 struct genl_ops op;
353
354 if (iter->entry_idx < family->n_ops) {
355 genl_op_from_full(family, iter->entry_idx, &op);
356 } else if (iter->entry_idx < family->n_ops + family->n_small_ops) {
357 genl_op_from_small(family, iter->entry_idx - family->n_ops,
358 &op);
359 } else if (iter->entry_idx <
360 family->n_ops + family->n_small_ops + family->n_split_ops) {
361 legacy_op = false;
362 /* updates entry_idx */
363 genl_op_from_split(iter);
364 } else {
365 return false;
366 }
367
368 iter->cmd_idx++;
369
370 if (legacy_op) {
371 iter->entry_idx++;
372
373 genl_cmd_full_to_split(&iter->doit, family,
374 &op, GENL_CMD_CAP_DO);
375 genl_cmd_full_to_split(&iter->dumpit, family,
376 &op, GENL_CMD_CAP_DUMP);
377 }
378
379 iter->cmd = iter->doit.cmd | iter->dumpit.cmd;
380 iter->flags = iter->doit.flags | iter->dumpit.flags;
381
382 return true;
383}
384
385static void
386genl_op_iter_copy(struct genl_op_iter *dst, struct genl_op_iter *src)
387{
388 *dst = *src;
389}
390
391static unsigned int genl_op_iter_idx(struct genl_op_iter *iter)
392{
393 return iter->cmd_idx;
394}
395
396static int genl_allocate_reserve_groups(int n_groups, int *first_id)
397{
398 unsigned long *new_groups;
399 int start = 0;
400 int i;
401 int id;
402 bool fits;
403
404 do {
405 if (start == 0)
406 id = find_first_zero_bit(mc_groups,
407 mc_groups_longs *
408 BITS_PER_LONG);
409 else
410 id = find_next_zero_bit(mc_groups,
411 mc_groups_longs * BITS_PER_LONG,
412 start);
413
414 fits = true;
415 for (i = id;
416 i < min_t(int, id + n_groups,
417 mc_groups_longs * BITS_PER_LONG);
418 i++) {
419 if (test_bit(i, mc_groups)) {
420 start = i;
421 fits = false;
422 break;
423 }
424 }
425
426 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
427 unsigned long new_longs = mc_groups_longs +
428 BITS_TO_LONGS(n_groups);
429 size_t nlen = new_longs * sizeof(unsigned long);
430
431 if (mc_groups == &mc_group_start) {
432 new_groups = kzalloc(nlen, GFP_KERNEL);
433 if (!new_groups)
434 return -ENOMEM;
435 mc_groups = new_groups;
436 *mc_groups = mc_group_start;
437 } else {
438 new_groups = krealloc(mc_groups, nlen,
439 GFP_KERNEL);
440 if (!new_groups)
441 return -ENOMEM;
442 mc_groups = new_groups;
443 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
444 mc_groups[mc_groups_longs + i] = 0;
445 }
446 mc_groups_longs = new_longs;
447 }
448 } while (!fits);
449
450 for (i = id; i < id + n_groups; i++)
451 set_bit(i, mc_groups);
452 *first_id = id;
453 return 0;
454}
455
456static struct genl_family genl_ctrl;
457
458static int genl_validate_assign_mc_groups(struct genl_family *family)
459{
460 int first_id;
461 int n_groups = family->n_mcgrps;
462 int err = 0, i;
463 bool groups_allocated = false;
464
465 if (!n_groups)
466 return 0;
467
468 for (i = 0; i < n_groups; i++) {
469 const struct genl_multicast_group *grp = &family->mcgrps[i];
470
471 if (WARN_ON(grp->name[0] == '\0'))
472 return -EINVAL;
473 if (WARN_ON(!string_is_terminated(grp->name, GENL_NAMSIZ)))
474 return -EINVAL;
475 }
476
477 /* special-case our own group and hacks */
478 if (family == &genl_ctrl) {
479 first_id = GENL_ID_CTRL;
480 BUG_ON(n_groups != 1);
481 } else if (strcmp(family->name, "NET_DM") == 0) {
482 first_id = 1;
483 BUG_ON(n_groups != 1);
484 } else if (family->id == GENL_ID_VFS_DQUOT) {
485 first_id = GENL_ID_VFS_DQUOT;
486 BUG_ON(n_groups != 1);
487 } else if (family->id == GENL_ID_PMCRAID) {
488 first_id = GENL_ID_PMCRAID;
489 BUG_ON(n_groups != 1);
490 } else {
491 groups_allocated = true;
492 err = genl_allocate_reserve_groups(n_groups, &first_id);
493 if (err)
494 return err;
495 }
496
497 family->mcgrp_offset = first_id;
498
499 /* if still initializing, can't and don't need to realloc bitmaps */
500 if (!init_net.genl_sock)
501 return 0;
502
503 if (family->netnsok) {
504 struct net *net;
505
506 netlink_table_grab();
507 rcu_read_lock();
508 for_each_net_rcu(net) {
509 err = __netlink_change_ngroups(net->genl_sock,
510 mc_groups_longs * BITS_PER_LONG);
511 if (err) {
512 /*
513 * No need to roll back, can only fail if
514 * memory allocation fails and then the
515 * number of _possible_ groups has been
516 * increased on some sockets which is ok.
517 */
518 break;
519 }
520 }
521 rcu_read_unlock();
522 netlink_table_ungrab();
523 } else {
524 err = netlink_change_ngroups(init_net.genl_sock,
525 mc_groups_longs * BITS_PER_LONG);
526 }
527
528 if (groups_allocated && err) {
529 for (i = 0; i < family->n_mcgrps; i++)
530 clear_bit(family->mcgrp_offset + i, mc_groups);
531 }
532
533 return err;
534}
535
536static void genl_unregister_mc_groups(const struct genl_family *family)
537{
538 struct net *net;
539 int i;
540
541 netlink_table_grab();
542 rcu_read_lock();
543 for_each_net_rcu(net) {
544 for (i = 0; i < family->n_mcgrps; i++)
545 __netlink_clear_multicast_users(
546 net->genl_sock, family->mcgrp_offset + i);
547 }
548 rcu_read_unlock();
549 netlink_table_ungrab();
550
551 for (i = 0; i < family->n_mcgrps; i++) {
552 int grp_id = family->mcgrp_offset + i;
553
554 if (grp_id != 1)
555 clear_bit(grp_id, mc_groups);
556 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
557 &family->mcgrps[i], grp_id);
558 }
559}
560
561static bool genl_split_op_check(const struct genl_split_ops *op)
562{
563 if (WARN_ON(hweight8(op->flags & (GENL_CMD_CAP_DO |
564 GENL_CMD_CAP_DUMP)) != 1))
565 return true;
566 return false;
567}
568
569static int genl_validate_ops(const struct genl_family *family)
570{
571 struct genl_op_iter i, j;
572 unsigned int s;
573
574 if (WARN_ON(family->n_ops && !family->ops) ||
575 WARN_ON(family->n_small_ops && !family->small_ops) ||
576 WARN_ON(family->n_split_ops && !family->split_ops))
577 return -EINVAL;
578
579 for (genl_op_iter_init(family, &i); genl_op_iter_next(&i); ) {
580 if (!(i.flags & (GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP)))
581 return -EINVAL;
582
583 if (WARN_ON(i.cmd >= family->resv_start_op &&
584 (i.doit.validate || i.dumpit.validate)))
585 return -EINVAL;
586
587 genl_op_iter_copy(&j, &i);
588 while (genl_op_iter_next(&j)) {
589 if (i.cmd == j.cmd)
590 return -EINVAL;
591 }
592 }
593
594 if (family->n_split_ops) {
595 if (genl_split_op_check(&family->split_ops[0]))
596 return -EINVAL;
597 }
598
599 for (s = 1; s < family->n_split_ops; s++) {
600 const struct genl_split_ops *a, *b;
601
602 a = &family->split_ops[s - 1];
603 b = &family->split_ops[s];
604
605 if (genl_split_op_check(b))
606 return -EINVAL;
607
608 /* Check sort order */
609 if (a->cmd < b->cmd) {
610 continue;
611 } else if (a->cmd > b->cmd) {
612 WARN_ON(1);
613 return -EINVAL;
614 }
615
616 if (a->internal_flags != b->internal_flags ||
617 ((a->flags ^ b->flags) & ~(GENL_CMD_CAP_DO |
618 GENL_CMD_CAP_DUMP))) {
619 WARN_ON(1);
620 return -EINVAL;
621 }
622
623 if ((a->flags & GENL_CMD_CAP_DO) &&
624 (b->flags & GENL_CMD_CAP_DUMP))
625 continue;
626
627 WARN_ON(1);
628 return -EINVAL;
629 }
630
631 return 0;
632}
633
634static void *genl_sk_priv_alloc(struct genl_family *family)
635{
636 void *priv;
637
638 priv = kzalloc(family->sock_priv_size, GFP_KERNEL);
639 if (!priv)
640 return ERR_PTR(-ENOMEM);
641
642 if (family->sock_priv_init)
643 family->sock_priv_init(priv);
644
645 return priv;
646}
647
648static void genl_sk_priv_free(const struct genl_family *family, void *priv)
649{
650 if (family->sock_priv_destroy)
651 family->sock_priv_destroy(priv);
652 kfree(priv);
653}
654
655static int genl_sk_privs_alloc(struct genl_family *family)
656{
657 if (!family->sock_priv_size)
658 return 0;
659
660 family->sock_privs = kzalloc(sizeof(*family->sock_privs), GFP_KERNEL);
661 if (!family->sock_privs)
662 return -ENOMEM;
663 xa_init(family->sock_privs);
664 return 0;
665}
666
667static void genl_sk_privs_free(const struct genl_family *family)
668{
669 unsigned long id;
670 void *priv;
671
672 if (!family->sock_priv_size)
673 return;
674
675 xa_for_each(family->sock_privs, id, priv)
676 genl_sk_priv_free(family, priv);
677
678 xa_destroy(family->sock_privs);
679 kfree(family->sock_privs);
680}
681
682static void genl_sk_priv_free_by_sock(struct genl_family *family,
683 struct sock *sk)
684{
685 void *priv;
686
687 if (!family->sock_priv_size)
688 return;
689 priv = xa_erase(family->sock_privs, (unsigned long) sk);
690 if (!priv)
691 return;
692 genl_sk_priv_free(family, priv);
693}
694
695static void genl_release(struct sock *sk, unsigned long *groups)
696{
697 struct genl_family *family;
698 unsigned int id;
699
700 down_read(&cb_lock);
701
702 idr_for_each_entry(&genl_fam_idr, family, id)
703 genl_sk_priv_free_by_sock(family, sk);
704
705 up_read(&cb_lock);
706}
707
708/**
709 * __genl_sk_priv_get - Get family private pointer for socket, if exists
710 *
711 * @family: family
712 * @sk: socket
713 *
714 * Lookup a private memory for a Generic netlink family and specified socket.
715 *
716 * Caller should make sure this is called in RCU read locked section.
717 *
718 * Return: valid pointer on success, otherwise negative error value
719 * encoded by ERR_PTR(), NULL in case priv does not exist.
720 */
721void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk)
722{
723 if (WARN_ON_ONCE(!family->sock_privs))
724 return ERR_PTR(-EINVAL);
725 return xa_load(family->sock_privs, (unsigned long) sk);
726}
727
728/**
729 * genl_sk_priv_get - Get family private pointer for socket
730 *
731 * @family: family
732 * @sk: socket
733 *
734 * Lookup a private memory for a Generic netlink family and specified socket.
735 * Allocate the private memory in case it was not already done.
736 *
737 * Return: valid pointer on success, otherwise negative error value
738 * encoded by ERR_PTR().
739 */
740void *genl_sk_priv_get(struct genl_family *family, struct sock *sk)
741{
742 void *priv, *old_priv;
743
744 priv = __genl_sk_priv_get(family, sk);
745 if (priv)
746 return priv;
747
748 /* priv for the family does not exist so far, create it. */
749
750 priv = genl_sk_priv_alloc(family);
751 if (IS_ERR(priv))
752 return ERR_CAST(priv);
753
754 old_priv = xa_cmpxchg(family->sock_privs, (unsigned long) sk, NULL,
755 priv, GFP_KERNEL);
756 if (old_priv) {
757 genl_sk_priv_free(family, priv);
758 if (xa_is_err(old_priv))
759 return ERR_PTR(xa_err(old_priv));
760 /* Race happened, priv for the socket was already inserted. */
761 return old_priv;
762 }
763 return priv;
764}
765
766/**
767 * genl_register_family - register a generic netlink family
768 * @family: generic netlink family
769 *
770 * Registers the specified family after validating it first. Only one
771 * family may be registered with the same family name or identifier.
772 *
773 * The family's ops, multicast groups and module pointer must already
774 * be assigned.
775 *
776 * Return 0 on success or a negative error code.
777 */
778int genl_register_family(struct genl_family *family)
779{
780 int err, i;
781 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
782
783 err = genl_validate_ops(family);
784 if (err)
785 return err;
786
787 genl_lock_all();
788
789 if (genl_family_find_byname(family->name)) {
790 err = -EEXIST;
791 goto errout_locked;
792 }
793
794 err = genl_sk_privs_alloc(family);
795 if (err)
796 goto errout_locked;
797
798 /*
799 * Sadly, a few cases need to be special-cased
800 * due to them having previously abused the API
801 * and having used their family ID also as their
802 * multicast group ID, so we use reserved IDs
803 * for both to be sure we can do that mapping.
804 */
805 if (family == &genl_ctrl) {
806 /* and this needs to be special for initial family lookups */
807 start = end = GENL_ID_CTRL;
808 } else if (strcmp(family->name, "pmcraid") == 0) {
809 start = end = GENL_ID_PMCRAID;
810 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
811 start = end = GENL_ID_VFS_DQUOT;
812 }
813
814 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
815 start, end + 1, GFP_KERNEL);
816 if (family->id < 0) {
817 err = family->id;
818 goto errout_sk_privs_free;
819 }
820
821 err = genl_validate_assign_mc_groups(family);
822 if (err)
823 goto errout_remove;
824
825 genl_unlock_all();
826
827 /* send all events */
828 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
829 for (i = 0; i < family->n_mcgrps; i++)
830 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
831 &family->mcgrps[i], family->mcgrp_offset + i);
832
833 return 0;
834
835errout_remove:
836 idr_remove(&genl_fam_idr, family->id);
837errout_sk_privs_free:
838 genl_sk_privs_free(family);
839errout_locked:
840 genl_unlock_all();
841 return err;
842}
843EXPORT_SYMBOL(genl_register_family);
844
845/**
846 * genl_unregister_family - unregister generic netlink family
847 * @family: generic netlink family
848 *
849 * Unregisters the specified family.
850 *
851 * Returns 0 on success or a negative error code.
852 */
853int genl_unregister_family(const struct genl_family *family)
854{
855 genl_lock_all();
856
857 if (!genl_family_find_byid(family->id)) {
858 genl_unlock_all();
859 return -ENOENT;
860 }
861
862 genl_unregister_mc_groups(family);
863
864 idr_remove(&genl_fam_idr, family->id);
865
866 up_write(&cb_lock);
867 wait_event(genl_sk_destructing_waitq,
868 atomic_read(&genl_sk_destructing_cnt) == 0);
869
870 genl_sk_privs_free(family);
871
872 genl_unlock();
873
874 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
875
876 return 0;
877}
878EXPORT_SYMBOL(genl_unregister_family);
879
880/**
881 * genlmsg_put - Add generic netlink header to netlink message
882 * @skb: socket buffer holding the message
883 * @portid: netlink portid the message is addressed to
884 * @seq: sequence number (usually the one of the sender)
885 * @family: generic netlink family
886 * @flags: netlink message flags
887 * @cmd: generic netlink command
888 *
889 * Returns pointer to user specific header
890 */
891void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
892 const struct genl_family *family, int flags, u8 cmd)
893{
894 struct nlmsghdr *nlh;
895 struct genlmsghdr *hdr;
896
897 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
898 family->hdrsize, flags);
899 if (nlh == NULL)
900 return NULL;
901
902 hdr = nlmsg_data(nlh);
903 hdr->cmd = cmd;
904 hdr->version = family->version;
905 hdr->reserved = 0;
906
907 return (char *) hdr + GENL_HDRLEN;
908}
909EXPORT_SYMBOL(genlmsg_put);
910
911static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
912{
913 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
914}
915
916static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
917{
918 kfree(info);
919}
920
921static struct nlattr **
922genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
923 struct nlmsghdr *nlh,
924 struct netlink_ext_ack *extack,
925 const struct genl_split_ops *ops,
926 int hdrlen,
927 enum genl_validate_flags no_strict_flag)
928{
929 enum netlink_validation validate = ops->validate & no_strict_flag ?
930 NL_VALIDATE_LIBERAL :
931 NL_VALIDATE_STRICT;
932 struct nlattr **attrbuf;
933 int err;
934
935 if (!ops->maxattr)
936 return NULL;
937
938 attrbuf = kmalloc_array(ops->maxattr + 1,
939 sizeof(struct nlattr *), GFP_KERNEL);
940 if (!attrbuf)
941 return ERR_PTR(-ENOMEM);
942
943 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
944 validate, extack);
945 if (err) {
946 kfree(attrbuf);
947 return ERR_PTR(err);
948 }
949 return attrbuf;
950}
951
952static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
953{
954 kfree(attrbuf);
955}
956
957struct genl_start_context {
958 const struct genl_family *family;
959 struct nlmsghdr *nlh;
960 struct netlink_ext_ack *extack;
961 const struct genl_split_ops *ops;
962 int hdrlen;
963};
964
965static int genl_start(struct netlink_callback *cb)
966{
967 struct genl_start_context *ctx = cb->data;
968 const struct genl_split_ops *ops;
969 struct genl_dumpit_info *info;
970 struct nlattr **attrs = NULL;
971 int rc = 0;
972
973 ops = ctx->ops;
974 if (!(ops->validate & GENL_DONT_VALIDATE_DUMP) &&
975 ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
976 return -EINVAL;
977
978 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
979 ops, ctx->hdrlen,
980 GENL_DONT_VALIDATE_DUMP_STRICT);
981 if (IS_ERR(attrs))
982 return PTR_ERR(attrs);
983
984 info = genl_dumpit_info_alloc();
985 if (!info) {
986 genl_family_rcv_msg_attrs_free(attrs);
987 return -ENOMEM;
988 }
989 info->op = *ops;
990 info->info.family = ctx->family;
991 info->info.snd_seq = cb->nlh->nlmsg_seq;
992 info->info.snd_portid = NETLINK_CB(cb->skb).portid;
993 info->info.nlhdr = cb->nlh;
994 info->info.genlhdr = nlmsg_data(cb->nlh);
995 info->info.attrs = attrs;
996 genl_info_net_set(&info->info, sock_net(cb->skb->sk));
997 info->info.extack = cb->extack;
998 memset(&info->info.user_ptr, 0, sizeof(info->info.user_ptr));
999
1000 cb->data = info;
1001 if (ops->start) {
1002 genl_op_lock(ctx->family);
1003 rc = ops->start(cb);
1004 genl_op_unlock(ctx->family);
1005 }
1006
1007 if (rc) {
1008 genl_family_rcv_msg_attrs_free(info->info.attrs);
1009 genl_dumpit_info_free(info);
1010 cb->data = NULL;
1011 }
1012 return rc;
1013}
1014
1015static int genl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
1016{
1017 struct genl_dumpit_info *dump_info = cb->data;
1018 const struct genl_split_ops *ops = &dump_info->op;
1019 struct genl_info *info = &dump_info->info;
1020 int rc;
1021
1022 info->extack = cb->extack;
1023
1024 genl_op_lock(info->family);
1025 rc = ops->dumpit(skb, cb);
1026 genl_op_unlock(info->family);
1027 return rc;
1028}
1029
1030static int genl_done(struct netlink_callback *cb)
1031{
1032 struct genl_dumpit_info *dump_info = cb->data;
1033 const struct genl_split_ops *ops = &dump_info->op;
1034 struct genl_info *info = &dump_info->info;
1035 int rc = 0;
1036
1037 info->extack = cb->extack;
1038
1039 if (ops->done) {
1040 genl_op_lock(info->family);
1041 rc = ops->done(cb);
1042 genl_op_unlock(info->family);
1043 }
1044 genl_family_rcv_msg_attrs_free(info->attrs);
1045 genl_dumpit_info_free(dump_info);
1046 return rc;
1047}
1048
1049static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
1050 struct sk_buff *skb,
1051 struct nlmsghdr *nlh,
1052 struct netlink_ext_ack *extack,
1053 const struct genl_split_ops *ops,
1054 int hdrlen, struct net *net)
1055{
1056 struct genl_start_context ctx;
1057 struct netlink_dump_control c = {
1058 .module = family->module,
1059 .data = &ctx,
1060 .start = genl_start,
1061 .dump = genl_dumpit,
1062 .done = genl_done,
1063 .extack = extack,
1064 };
1065 int err;
1066
1067 ctx.family = family;
1068 ctx.nlh = nlh;
1069 ctx.extack = extack;
1070 ctx.ops = ops;
1071 ctx.hdrlen = hdrlen;
1072
1073 genl_op_unlock(family);
1074 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
1075 genl_op_lock(family);
1076
1077 return err;
1078}
1079
1080static int genl_family_rcv_msg_doit(const struct genl_family *family,
1081 struct sk_buff *skb,
1082 struct nlmsghdr *nlh,
1083 struct netlink_ext_ack *extack,
1084 const struct genl_split_ops *ops,
1085 int hdrlen, struct net *net)
1086{
1087 struct nlattr **attrbuf;
1088 struct genl_info info;
1089 int err;
1090
1091 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
1092 ops, hdrlen,
1093 GENL_DONT_VALIDATE_STRICT);
1094 if (IS_ERR(attrbuf))
1095 return PTR_ERR(attrbuf);
1096
1097 info.snd_seq = nlh->nlmsg_seq;
1098 info.snd_portid = NETLINK_CB(skb).portid;
1099 info.family = family;
1100 info.nlhdr = nlh;
1101 info.genlhdr = nlmsg_data(nlh);
1102 info.attrs = attrbuf;
1103 info.extack = extack;
1104 genl_info_net_set(&info, net);
1105 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
1106
1107 if (ops->pre_doit) {
1108 err = ops->pre_doit(ops, skb, &info);
1109 if (err)
1110 goto out;
1111 }
1112
1113 err = ops->doit(skb, &info);
1114
1115 if (ops->post_doit)
1116 ops->post_doit(ops, skb, &info);
1117
1118out:
1119 genl_family_rcv_msg_attrs_free(attrbuf);
1120
1121 return err;
1122}
1123
1124static int genl_header_check(const struct genl_family *family,
1125 struct nlmsghdr *nlh, struct genlmsghdr *hdr,
1126 struct netlink_ext_ack *extack)
1127{
1128 u16 flags;
1129
1130 /* Only for commands added after we started validating */
1131 if (hdr->cmd < family->resv_start_op)
1132 return 0;
1133
1134 if (hdr->reserved) {
1135 NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0");
1136 return -EINVAL;
1137 }
1138
1139 /* Old netlink flags have pretty loose semantics, allow only the flags
1140 * consumed by the core where we can enforce the meaning.
1141 */
1142 flags = nlh->nlmsg_flags;
1143 if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */
1144 flags &= ~NLM_F_DUMP;
1145 if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) {
1146 NL_SET_ERR_MSG(extack,
1147 "ambiguous or reserved bits set in nlmsg_flags");
1148 return -EINVAL;
1149 }
1150
1151 return 0;
1152}
1153
1154static int genl_family_rcv_msg(const struct genl_family *family,
1155 struct sk_buff *skb,
1156 struct nlmsghdr *nlh,
1157 struct netlink_ext_ack *extack)
1158{
1159 struct net *net = sock_net(skb->sk);
1160 struct genlmsghdr *hdr = nlmsg_data(nlh);
1161 struct genl_split_ops op;
1162 int hdrlen;
1163 u8 flags;
1164
1165 /* this family doesn't exist in this netns */
1166 if (!family->netnsok && !net_eq(net, &init_net))
1167 return -ENOENT;
1168
1169 hdrlen = GENL_HDRLEN + family->hdrsize;
1170 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
1171 return -EINVAL;
1172
1173 if (genl_header_check(family, nlh, hdr, extack))
1174 return -EINVAL;
1175
1176 flags = (nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP ?
1177 GENL_CMD_CAP_DUMP : GENL_CMD_CAP_DO;
1178 if (genl_get_cmd(hdr->cmd, flags, family, &op))
1179 return -EOPNOTSUPP;
1180
1181 if ((op.flags & GENL_ADMIN_PERM) &&
1182 !netlink_capable(skb, CAP_NET_ADMIN))
1183 return -EPERM;
1184
1185 if ((op.flags & GENL_UNS_ADMIN_PERM) &&
1186 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
1187 return -EPERM;
1188
1189 if (flags & GENL_CMD_CAP_DUMP)
1190 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
1191 &op, hdrlen, net);
1192 else
1193 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
1194 &op, hdrlen, net);
1195}
1196
1197static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
1198 struct netlink_ext_ack *extack)
1199{
1200 const struct genl_family *family;
1201 int err;
1202
1203 family = genl_family_find_byid(nlh->nlmsg_type);
1204 if (family == NULL)
1205 return -ENOENT;
1206
1207 genl_op_lock(family);
1208 err = genl_family_rcv_msg(family, skb, nlh, extack);
1209 genl_op_unlock(family);
1210
1211 return err;
1212}
1213
1214static void genl_rcv(struct sk_buff *skb)
1215{
1216 down_read(&cb_lock);
1217 netlink_rcv_skb(skb, &genl_rcv_msg);
1218 up_read(&cb_lock);
1219}
1220
1221/**************************************************************************
1222 * Controller
1223 **************************************************************************/
1224
1225static struct genl_family genl_ctrl;
1226
1227static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
1228 u32 flags, struct sk_buff *skb, u8 cmd)
1229{
1230 struct genl_op_iter i;
1231 void *hdr;
1232
1233 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
1234 if (hdr == NULL)
1235 return -1;
1236
1237 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
1238 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
1239 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
1240 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
1241 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
1242 goto nla_put_failure;
1243
1244 if (genl_op_iter_init(family, &i)) {
1245 struct nlattr *nla_ops;
1246
1247 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
1248 if (nla_ops == NULL)
1249 goto nla_put_failure;
1250
1251 while (genl_op_iter_next(&i)) {
1252 struct nlattr *nest;
1253 u32 op_flags;
1254
1255 op_flags = i.flags;
1256 if (i.doit.policy || i.dumpit.policy)
1257 op_flags |= GENL_CMD_CAP_HASPOL;
1258
1259 nest = nla_nest_start_noflag(skb, genl_op_iter_idx(&i));
1260 if (nest == NULL)
1261 goto nla_put_failure;
1262
1263 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, i.cmd) ||
1264 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
1265 goto nla_put_failure;
1266
1267 nla_nest_end(skb, nest);
1268 }
1269
1270 nla_nest_end(skb, nla_ops);
1271 }
1272
1273 if (family->n_mcgrps) {
1274 struct nlattr *nla_grps;
1275 int i;
1276
1277 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
1278 if (nla_grps == NULL)
1279 goto nla_put_failure;
1280
1281 for (i = 0; i < family->n_mcgrps; i++) {
1282 struct nlattr *nest;
1283 const struct genl_multicast_group *grp;
1284
1285 grp = &family->mcgrps[i];
1286
1287 nest = nla_nest_start_noflag(skb, i + 1);
1288 if (nest == NULL)
1289 goto nla_put_failure;
1290
1291 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
1292 family->mcgrp_offset + i) ||
1293 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
1294 grp->name))
1295 goto nla_put_failure;
1296
1297 nla_nest_end(skb, nest);
1298 }
1299 nla_nest_end(skb, nla_grps);
1300 }
1301
1302 genlmsg_end(skb, hdr);
1303 return 0;
1304
1305nla_put_failure:
1306 genlmsg_cancel(skb, hdr);
1307 return -EMSGSIZE;
1308}
1309
1310static int ctrl_fill_mcgrp_info(const struct genl_family *family,
1311 const struct genl_multicast_group *grp,
1312 int grp_id, u32 portid, u32 seq, u32 flags,
1313 struct sk_buff *skb, u8 cmd)
1314{
1315 void *hdr;
1316 struct nlattr *nla_grps;
1317 struct nlattr *nest;
1318
1319 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
1320 if (hdr == NULL)
1321 return -1;
1322
1323 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
1324 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
1325 goto nla_put_failure;
1326
1327 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
1328 if (nla_grps == NULL)
1329 goto nla_put_failure;
1330
1331 nest = nla_nest_start_noflag(skb, 1);
1332 if (nest == NULL)
1333 goto nla_put_failure;
1334
1335 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
1336 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
1337 grp->name))
1338 goto nla_put_failure;
1339
1340 nla_nest_end(skb, nest);
1341 nla_nest_end(skb, nla_grps);
1342
1343 genlmsg_end(skb, hdr);
1344 return 0;
1345
1346nla_put_failure:
1347 genlmsg_cancel(skb, hdr);
1348 return -EMSGSIZE;
1349}
1350
1351static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
1352{
1353 int n = 0;
1354 struct genl_family *rt;
1355 struct net *net = sock_net(skb->sk);
1356 int fams_to_skip = cb->args[0];
1357 unsigned int id;
1358
1359 idr_for_each_entry(&genl_fam_idr, rt, id) {
1360 if (!rt->netnsok && !net_eq(net, &init_net))
1361 continue;
1362
1363 if (n++ < fams_to_skip)
1364 continue;
1365
1366 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
1367 cb->nlh->nlmsg_seq, NLM_F_MULTI,
1368 skb, CTRL_CMD_NEWFAMILY) < 0) {
1369 n--;
1370 break;
1371 }
1372 }
1373
1374 cb->args[0] = n;
1375 return skb->len;
1376}
1377
1378static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
1379 u32 portid, int seq, u8 cmd)
1380{
1381 struct sk_buff *skb;
1382 int err;
1383
1384 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1385 if (skb == NULL)
1386 return ERR_PTR(-ENOBUFS);
1387
1388 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
1389 if (err < 0) {
1390 nlmsg_free(skb);
1391 return ERR_PTR(err);
1392 }
1393
1394 return skb;
1395}
1396
1397static struct sk_buff *
1398ctrl_build_mcgrp_msg(const struct genl_family *family,
1399 const struct genl_multicast_group *grp,
1400 int grp_id, u32 portid, int seq, u8 cmd)
1401{
1402 struct sk_buff *skb;
1403 int err;
1404
1405 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1406 if (skb == NULL)
1407 return ERR_PTR(-ENOBUFS);
1408
1409 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1410 seq, 0, skb, cmd);
1411 if (err < 0) {
1412 nlmsg_free(skb);
1413 return ERR_PTR(err);
1414 }
1415
1416 return skb;
1417}
1418
1419static const struct nla_policy ctrl_policy_family[] = {
1420 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1421 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1422 .len = GENL_NAMSIZ - 1 },
1423};
1424
1425static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1426{
1427 struct sk_buff *msg;
1428 const struct genl_family *res = NULL;
1429 int err = -EINVAL;
1430
1431 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1432 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1433 res = genl_family_find_byid(id);
1434 err = -ENOENT;
1435 }
1436
1437 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1438 char *name;
1439
1440 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1441 res = genl_family_find_byname(name);
1442#ifdef CONFIG_MODULES
1443 if (res == NULL) {
1444 genl_unlock();
1445 up_read(&cb_lock);
1446 request_module("net-pf-%d-proto-%d-family-%s",
1447 PF_NETLINK, NETLINK_GENERIC, name);
1448 down_read(&cb_lock);
1449 genl_lock();
1450 res = genl_family_find_byname(name);
1451 }
1452#endif
1453 err = -ENOENT;
1454 }
1455
1456 if (res == NULL)
1457 return err;
1458
1459 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1460 /* family doesn't exist here */
1461 return -ENOENT;
1462 }
1463
1464 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1465 CTRL_CMD_NEWFAMILY);
1466 if (IS_ERR(msg))
1467 return PTR_ERR(msg);
1468
1469 return genlmsg_reply(msg, info);
1470}
1471
1472static int genl_ctrl_event(int event, const struct genl_family *family,
1473 const struct genl_multicast_group *grp,
1474 int grp_id)
1475{
1476 struct sk_buff *msg;
1477
1478 /* genl is still initialising */
1479 if (!init_net.genl_sock)
1480 return 0;
1481
1482 switch (event) {
1483 case CTRL_CMD_NEWFAMILY:
1484 case CTRL_CMD_DELFAMILY:
1485 WARN_ON(grp);
1486 msg = ctrl_build_family_msg(family, 0, 0, event);
1487 break;
1488 case CTRL_CMD_NEWMCAST_GRP:
1489 case CTRL_CMD_DELMCAST_GRP:
1490 BUG_ON(!grp);
1491 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1492 break;
1493 default:
1494 return -EINVAL;
1495 }
1496
1497 if (IS_ERR(msg))
1498 return PTR_ERR(msg);
1499
1500 if (!family->netnsok) {
1501 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1502 0, GFP_KERNEL);
1503 } else {
1504 rcu_read_lock();
1505 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1506 0, GFP_ATOMIC);
1507 rcu_read_unlock();
1508 }
1509
1510 return 0;
1511}
1512
1513struct ctrl_dump_policy_ctx {
1514 struct netlink_policy_dump_state *state;
1515 const struct genl_family *rt;
1516 struct genl_op_iter *op_iter;
1517 u32 op;
1518 u16 fam_id;
1519 u8 dump_map:1,
1520 single_op:1;
1521};
1522
1523static const struct nla_policy ctrl_policy_policy[] = {
1524 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1525 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1526 .len = GENL_NAMSIZ - 1 },
1527 [CTRL_ATTR_OP] = { .type = NLA_U32 },
1528};
1529
1530static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1531{
1532 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1533 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1534 struct nlattr **tb = info->info.attrs;
1535 const struct genl_family *rt;
1536 struct genl_op_iter i;
1537 int err;
1538
1539 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1540
1541 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1542 return -EINVAL;
1543
1544 if (tb[CTRL_ATTR_FAMILY_ID]) {
1545 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1546 } else {
1547 rt = genl_family_find_byname(
1548 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1549 if (!rt)
1550 return -ENOENT;
1551 ctx->fam_id = rt->id;
1552 }
1553
1554 rt = genl_family_find_byid(ctx->fam_id);
1555 if (!rt)
1556 return -ENOENT;
1557
1558 ctx->rt = rt;
1559
1560 if (tb[CTRL_ATTR_OP]) {
1561 struct genl_split_ops doit, dump;
1562
1563 ctx->single_op = true;
1564 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1565
1566 err = genl_get_cmd_both(ctx->op, rt, &doit, &dump);
1567 if (err) {
1568 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1569 return err;
1570 }
1571
1572 if (doit.policy) {
1573 err = netlink_policy_dump_add_policy(&ctx->state,
1574 doit.policy,
1575 doit.maxattr);
1576 if (err)
1577 goto err_free_state;
1578 }
1579 if (dump.policy) {
1580 err = netlink_policy_dump_add_policy(&ctx->state,
1581 dump.policy,
1582 dump.maxattr);
1583 if (err)
1584 goto err_free_state;
1585 }
1586
1587 if (!ctx->state)
1588 return -ENODATA;
1589
1590 ctx->dump_map = 1;
1591 return 0;
1592 }
1593
1594 ctx->op_iter = kmalloc(sizeof(*ctx->op_iter), GFP_KERNEL);
1595 if (!ctx->op_iter)
1596 return -ENOMEM;
1597
1598 genl_op_iter_init(rt, ctx->op_iter);
1599 ctx->dump_map = genl_op_iter_next(ctx->op_iter);
1600
1601 for (genl_op_iter_init(rt, &i); genl_op_iter_next(&i); ) {
1602 if (i.doit.policy) {
1603 err = netlink_policy_dump_add_policy(&ctx->state,
1604 i.doit.policy,
1605 i.doit.maxattr);
1606 if (err)
1607 goto err_free_state;
1608 }
1609 if (i.dumpit.policy) {
1610 err = netlink_policy_dump_add_policy(&ctx->state,
1611 i.dumpit.policy,
1612 i.dumpit.maxattr);
1613 if (err)
1614 goto err_free_state;
1615 }
1616 }
1617
1618 if (!ctx->state) {
1619 err = -ENODATA;
1620 goto err_free_op_iter;
1621 }
1622 return 0;
1623
1624err_free_state:
1625 netlink_policy_dump_free(ctx->state);
1626err_free_op_iter:
1627 kfree(ctx->op_iter);
1628 return err;
1629}
1630
1631static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1632 struct netlink_callback *cb)
1633{
1634 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1635 void *hdr;
1636
1637 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1638 cb->nlh->nlmsg_seq, &genl_ctrl,
1639 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1640 if (!hdr)
1641 return NULL;
1642
1643 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1644 return NULL;
1645
1646 return hdr;
1647}
1648
1649static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1650 struct netlink_callback *cb,
1651 struct genl_split_ops *doit,
1652 struct genl_split_ops *dumpit)
1653{
1654 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1655 struct nlattr *nest_pol, *nest_op;
1656 void *hdr;
1657 int idx;
1658
1659 /* skip if we have nothing to show */
1660 if (!doit->policy && !dumpit->policy)
1661 return 0;
1662
1663 hdr = ctrl_dumppolicy_prep(skb, cb);
1664 if (!hdr)
1665 return -ENOBUFS;
1666
1667 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1668 if (!nest_pol)
1669 goto err;
1670
1671 nest_op = nla_nest_start(skb, doit->cmd);
1672 if (!nest_op)
1673 goto err;
1674
1675 if (doit->policy) {
1676 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1677 doit->policy,
1678 doit->maxattr);
1679
1680 if (nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1681 goto err;
1682 }
1683 if (dumpit->policy) {
1684 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1685 dumpit->policy,
1686 dumpit->maxattr);
1687
1688 if (nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1689 goto err;
1690 }
1691
1692 nla_nest_end(skb, nest_op);
1693 nla_nest_end(skb, nest_pol);
1694 genlmsg_end(skb, hdr);
1695
1696 return 0;
1697err:
1698 genlmsg_cancel(skb, hdr);
1699 return -ENOBUFS;
1700}
1701
1702static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1703{
1704 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1705 void *hdr;
1706
1707 if (ctx->dump_map) {
1708 if (ctx->single_op) {
1709 struct genl_split_ops doit, dumpit;
1710
1711 if (WARN_ON(genl_get_cmd_both(ctx->op, ctx->rt,
1712 &doit, &dumpit)))
1713 return -ENOENT;
1714
1715 if (ctrl_dumppolicy_put_op(skb, cb, &doit, &dumpit))
1716 return skb->len;
1717
1718 /* done with the per-op policy index list */
1719 ctx->dump_map = 0;
1720 }
1721
1722 while (ctx->dump_map) {
1723 if (ctrl_dumppolicy_put_op(skb, cb,
1724 &ctx->op_iter->doit,
1725 &ctx->op_iter->dumpit))
1726 return skb->len;
1727
1728 ctx->dump_map = genl_op_iter_next(ctx->op_iter);
1729 }
1730 }
1731
1732 while (netlink_policy_dump_loop(ctx->state)) {
1733 struct nlattr *nest;
1734
1735 hdr = ctrl_dumppolicy_prep(skb, cb);
1736 if (!hdr)
1737 goto nla_put_failure;
1738
1739 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1740 if (!nest)
1741 goto nla_put_failure;
1742
1743 if (netlink_policy_dump_write(skb, ctx->state))
1744 goto nla_put_failure;
1745
1746 nla_nest_end(skb, nest);
1747
1748 genlmsg_end(skb, hdr);
1749 }
1750
1751 return skb->len;
1752
1753nla_put_failure:
1754 genlmsg_cancel(skb, hdr);
1755 return skb->len;
1756}
1757
1758static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1759{
1760 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1761
1762 kfree(ctx->op_iter);
1763 netlink_policy_dump_free(ctx->state);
1764 return 0;
1765}
1766
1767static const struct genl_split_ops genl_ctrl_ops[] = {
1768 {
1769 .cmd = CTRL_CMD_GETFAMILY,
1770 .validate = GENL_DONT_VALIDATE_STRICT,
1771 .policy = ctrl_policy_family,
1772 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1773 .doit = ctrl_getfamily,
1774 .flags = GENL_CMD_CAP_DO,
1775 },
1776 {
1777 .cmd = CTRL_CMD_GETFAMILY,
1778 .validate = GENL_DONT_VALIDATE_DUMP,
1779 .policy = ctrl_policy_family,
1780 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1781 .dumpit = ctrl_dumpfamily,
1782 .flags = GENL_CMD_CAP_DUMP,
1783 },
1784 {
1785 .cmd = CTRL_CMD_GETPOLICY,
1786 .policy = ctrl_policy_policy,
1787 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1,
1788 .start = ctrl_dumppolicy_start,
1789 .dumpit = ctrl_dumppolicy,
1790 .done = ctrl_dumppolicy_done,
1791 .flags = GENL_CMD_CAP_DUMP,
1792 },
1793};
1794
1795static const struct genl_multicast_group genl_ctrl_groups[] = {
1796 { .name = "notify", },
1797};
1798
1799static struct genl_family genl_ctrl __ro_after_init = {
1800 .module = THIS_MODULE,
1801 .split_ops = genl_ctrl_ops,
1802 .n_split_ops = ARRAY_SIZE(genl_ctrl_ops),
1803 .resv_start_op = CTRL_CMD_GETPOLICY + 1,
1804 .mcgrps = genl_ctrl_groups,
1805 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1806 .id = GENL_ID_CTRL,
1807 .name = "nlctrl",
1808 .version = 0x2,
1809 .netnsok = true,
1810};
1811
1812static int genl_bind(struct net *net, int group)
1813{
1814 const struct genl_family *family;
1815 unsigned int id;
1816 int ret = 0;
1817
1818 down_read(&cb_lock);
1819
1820 idr_for_each_entry(&genl_fam_idr, family, id) {
1821 const struct genl_multicast_group *grp;
1822 int i;
1823
1824 if (family->n_mcgrps == 0)
1825 continue;
1826
1827 i = group - family->mcgrp_offset;
1828 if (i < 0 || i >= family->n_mcgrps)
1829 continue;
1830
1831 grp = &family->mcgrps[i];
1832 if ((grp->flags & GENL_MCAST_CAP_NET_ADMIN) &&
1833 !ns_capable(net->user_ns, CAP_NET_ADMIN))
1834 ret = -EPERM;
1835 if ((grp->flags & GENL_MCAST_CAP_SYS_ADMIN) &&
1836 !ns_capable(net->user_ns, CAP_SYS_ADMIN))
1837 ret = -EPERM;
1838
1839 break;
1840 }
1841
1842 up_read(&cb_lock);
1843 return ret;
1844}
1845
1846static int __net_init genl_pernet_init(struct net *net)
1847{
1848 struct netlink_kernel_cfg cfg = {
1849 .input = genl_rcv,
1850 .flags = NL_CFG_F_NONROOT_RECV,
1851 .bind = genl_bind,
1852 .release = genl_release,
1853 };
1854
1855 /* we'll bump the group number right afterwards */
1856 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1857
1858 if (!net->genl_sock && net_eq(net, &init_net))
1859 panic("GENL: Cannot initialize generic netlink\n");
1860
1861 if (!net->genl_sock)
1862 return -ENOMEM;
1863
1864 return 0;
1865}
1866
1867static void __net_exit genl_pernet_exit(struct net *net)
1868{
1869 netlink_kernel_release(net->genl_sock);
1870 net->genl_sock = NULL;
1871}
1872
1873static struct pernet_operations genl_pernet_ops = {
1874 .init = genl_pernet_init,
1875 .exit = genl_pernet_exit,
1876};
1877
1878static int __init genl_init(void)
1879{
1880 int err;
1881
1882 err = genl_register_family(&genl_ctrl);
1883 if (err < 0)
1884 goto problem;
1885
1886 err = register_pernet_subsys(&genl_pernet_ops);
1887 if (err)
1888 goto problem;
1889
1890 return 0;
1891
1892problem:
1893 panic("GENL: Cannot register controller: %d\n", err);
1894}
1895
1896core_initcall(genl_init);
1897
1898static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1899 gfp_t flags)
1900{
1901 struct sk_buff *tmp;
1902 struct net *net, *prev = NULL;
1903 bool delivered = false;
1904 int err;
1905
1906 for_each_net_rcu(net) {
1907 if (prev) {
1908 tmp = skb_clone(skb, flags);
1909 if (!tmp) {
1910 err = -ENOMEM;
1911 goto error;
1912 }
1913 err = nlmsg_multicast(prev->genl_sock, tmp,
1914 portid, group, flags);
1915 if (!err)
1916 delivered = true;
1917 else if (err != -ESRCH)
1918 goto error;
1919 }
1920
1921 prev = net;
1922 }
1923
1924 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1925 if (!err)
1926 delivered = true;
1927 else if (err != -ESRCH)
1928 return err;
1929 return delivered ? 0 : -ESRCH;
1930 error:
1931 kfree_skb(skb);
1932 return err;
1933}
1934
1935int genlmsg_multicast_allns(const struct genl_family *family,
1936 struct sk_buff *skb, u32 portid,
1937 unsigned int group, gfp_t flags)
1938{
1939 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1940 return -EINVAL;
1941
1942 group = family->mcgrp_offset + group;
1943 return genlmsg_mcast(skb, portid, group, flags);
1944}
1945EXPORT_SYMBOL(genlmsg_multicast_allns);
1946
1947void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1948 struct genl_info *info, u32 group, gfp_t flags)
1949{
1950 struct net *net = genl_info_net(info);
1951 struct sock *sk = net->genl_sock;
1952
1953 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1954 return;
1955
1956 group = family->mcgrp_offset + group;
1957 nlmsg_notify(sk, skb, info->snd_portid, group,
1958 nlmsg_report(info->nlhdr), flags);
1959}
1960EXPORT_SYMBOL(genl_notify);