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