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Linux 4.19.133
[linux/fpc-iii.git] / net / netlink / genetlink.c
blobf0ec068e1d02fc0ebd39c2b1ecd935a301647ab1
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NETLINK Generic Netlink Family
4 *
5 * Authors: Jamal Hadi Salim
6 * Thomas Graf <tgraf@suug.ch>
7 * Johannes Berg <johannes@sipsolutions.net>
8 */
9
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/errno.h>
14 #include <linux/types.h>
15 #include <linux/socket.h>
16 #include <linux/string.h>
17 #include <linux/skbuff.h>
18 #include <linux/mutex.h>
19 #include <linux/bitmap.h>
20 #include <linux/rwsem.h>
21 #include <linux/idr.h>
22 #include <net/sock.h>
23 #include <net/genetlink.h>
24
25 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
26 static DECLARE_RWSEM(cb_lock);
27
28 atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
29 DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
30
31 void genl_lock(void)
32 {
33 mutex_lock(&genl_mutex);
34 }
35 EXPORT_SYMBOL(genl_lock);
36
37 void genl_unlock(void)
38 {
39 mutex_unlock(&genl_mutex);
40 }
41 EXPORT_SYMBOL(genl_unlock);
42
43 #ifdef CONFIG_LOCKDEP
44 bool lockdep_genl_is_held(void)
45 {
46 return lockdep_is_held(&genl_mutex);
47 }
48 EXPORT_SYMBOL(lockdep_genl_is_held);
49 #endif
50
51 static void genl_lock_all(void)
52 {
53 down_write(&cb_lock);
54 genl_lock();
55 }
56
57 static void genl_unlock_all(void)
58 {
59 genl_unlock();
60 up_write(&cb_lock);
61 }
62
63 static 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 */
83 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
84 BIT(GENL_ID_VFS_DQUOT) |
85 BIT(GENL_ID_PMCRAID);
86 static unsigned long *mc_groups = &mc_group_start;
87 static unsigned long mc_groups_longs = 1;
88
89 static int genl_ctrl_event(int event, const struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93 static const struct genl_family *genl_family_find_byid(unsigned int id)
94 {
95 return idr_find(&genl_fam_idr, id);
96 }
97
98 static 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
110 static const struct genl_ops *genl_get_cmd(u8 cmd,
111 const struct genl_family *family)
112 {
113 int i;
114
115 for (i = 0; i < family->n_ops; i++)
116 if (family->ops[i].cmd == cmd)
117 return &family->ops[i];
118
119 return NULL;
120 }
121
122 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
123 {
124 unsigned long *new_groups;
125 int start = 0;
126 int i;
127 int id;
128 bool fits;
129
130 do {
131 if (start == 0)
132 id = find_first_zero_bit(mc_groups,
133 mc_groups_longs *
134 BITS_PER_LONG);
135 else
136 id = find_next_zero_bit(mc_groups,
137 mc_groups_longs * BITS_PER_LONG,
138 start);
139
140 fits = true;
141 for (i = id;
142 i < min_t(int, id + n_groups,
143 mc_groups_longs * BITS_PER_LONG);
144 i++) {
145 if (test_bit(i, mc_groups)) {
146 start = i;
147 fits = false;
148 break;
149 }
150 }
151
152 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
153 unsigned long new_longs = mc_groups_longs +
154 BITS_TO_LONGS(n_groups);
155 size_t nlen = new_longs * sizeof(unsigned long);
156
157 if (mc_groups == &mc_group_start) {
158 new_groups = kzalloc(nlen, GFP_KERNEL);
159 if (!new_groups)
160 return -ENOMEM;
161 mc_groups = new_groups;
162 *mc_groups = mc_group_start;
163 } else {
164 new_groups = krealloc(mc_groups, nlen,
165 GFP_KERNEL);
166 if (!new_groups)
167 return -ENOMEM;
168 mc_groups = new_groups;
169 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
170 mc_groups[mc_groups_longs + i] = 0;
171 }
172 mc_groups_longs = new_longs;
173 }
174 } while (!fits);
175
176 for (i = id; i < id + n_groups; i++)
177 set_bit(i, mc_groups);
178 *first_id = id;
179 return 0;
180 }
181
182 static struct genl_family genl_ctrl;
183
184 static int genl_validate_assign_mc_groups(struct genl_family *family)
185 {
186 int first_id;
187 int n_groups = family->n_mcgrps;
188 int err = 0, i;
189 bool groups_allocated = false;
190
191 if (!n_groups)
192 return 0;
193
194 for (i = 0; i < n_groups; i++) {
195 const struct genl_multicast_group *grp = &family->mcgrps[i];
196
197 if (WARN_ON(grp->name[0] == '\0'))
198 return -EINVAL;
199 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
200 return -EINVAL;
201 }
202
203 /* special-case our own group and hacks */
204 if (family == &genl_ctrl) {
205 first_id = GENL_ID_CTRL;
206 BUG_ON(n_groups != 1);
207 } else if (strcmp(family->name, "NET_DM") == 0) {
208 first_id = 1;
209 BUG_ON(n_groups != 1);
210 } else if (family->id == GENL_ID_VFS_DQUOT) {
211 first_id = GENL_ID_VFS_DQUOT;
212 BUG_ON(n_groups != 1);
213 } else if (family->id == GENL_ID_PMCRAID) {
214 first_id = GENL_ID_PMCRAID;
215 BUG_ON(n_groups != 1);
216 } else {
217 groups_allocated = true;
218 err = genl_allocate_reserve_groups(n_groups, &first_id);
219 if (err)
220 return err;
221 }
222
223 family->mcgrp_offset = first_id;
224
225 /* if still initializing, can't and don't need to to realloc bitmaps */
226 if (!init_net.genl_sock)
227 return 0;
228
229 if (family->netnsok) {
230 struct net *net;
231
232 netlink_table_grab();
233 rcu_read_lock();
234 for_each_net_rcu(net) {
235 err = __netlink_change_ngroups(net->genl_sock,
236 mc_groups_longs * BITS_PER_LONG);
237 if (err) {
238 /*
239 * No need to roll back, can only fail if
240 * memory allocation fails and then the
241 * number of _possible_ groups has been
242 * increased on some sockets which is ok.
243 */
244 break;
245 }
246 }
247 rcu_read_unlock();
248 netlink_table_ungrab();
249 } else {
250 err = netlink_change_ngroups(init_net.genl_sock,
251 mc_groups_longs * BITS_PER_LONG);
252 }
253
254 if (groups_allocated && err) {
255 for (i = 0; i < family->n_mcgrps; i++)
256 clear_bit(family->mcgrp_offset + i, mc_groups);
257 }
258
259 return err;
260 }
261
262 static void genl_unregister_mc_groups(const struct genl_family *family)
263 {
264 struct net *net;
265 int i;
266
267 netlink_table_grab();
268 rcu_read_lock();
269 for_each_net_rcu(net) {
270 for (i = 0; i < family->n_mcgrps; i++)
271 __netlink_clear_multicast_users(
272 net->genl_sock, family->mcgrp_offset + i);
273 }
274 rcu_read_unlock();
275 netlink_table_ungrab();
276
277 for (i = 0; i < family->n_mcgrps; i++) {
278 int grp_id = family->mcgrp_offset + i;
279
280 if (grp_id != 1)
281 clear_bit(grp_id, mc_groups);
282 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
283 &family->mcgrps[i], grp_id);
284 }
285 }
286
287 static int genl_validate_ops(const struct genl_family *family)
288 {
289 const struct genl_ops *ops = family->ops;
290 unsigned int n_ops = family->n_ops;
291 int i, j;
292
293 if (WARN_ON(n_ops && !ops))
294 return -EINVAL;
295
296 if (!n_ops)
297 return 0;
298
299 for (i = 0; i < n_ops; i++) {
300 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
301 return -EINVAL;
302 for (j = i + 1; j < n_ops; j++)
303 if (ops[i].cmd == ops[j].cmd)
304 return -EINVAL;
305 }
306
307 return 0;
308 }
309
310 /**
311 * genl_register_family - register a generic netlink family
312 * @family: generic netlink family
313 *
314 * Registers the specified family after validating it first. Only one
315 * family may be registered with the same family name or identifier.
316 *
317 * The family's ops, multicast groups and module pointer must already
318 * be assigned.
319 *
320 * Return 0 on success or a negative error code.
321 */
322 int genl_register_family(struct genl_family *family)
323 {
324 int err, i;
325 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
326
327 err = genl_validate_ops(family);
328 if (err)
329 return err;
330
331 genl_lock_all();
332
333 if (genl_family_find_byname(family->name)) {
334 err = -EEXIST;
335 goto errout_locked;
336 }
337
338 /*
339 * Sadly, a few cases need to be special-cased
340 * due to them having previously abused the API
341 * and having used their family ID also as their
342 * multicast group ID, so we use reserved IDs
343 * for both to be sure we can do that mapping.
344 */
345 if (family == &genl_ctrl) {
346 /* and this needs to be special for initial family lookups */
347 start = end = GENL_ID_CTRL;
348 } else if (strcmp(family->name, "pmcraid") == 0) {
349 start = end = GENL_ID_PMCRAID;
350 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
351 start = end = GENL_ID_VFS_DQUOT;
352 }
353
354 if (family->maxattr && !family->parallel_ops) {
355 family->attrbuf = kmalloc_array(family->maxattr + 1,
356 sizeof(struct nlattr *),
357 GFP_KERNEL);
358 if (family->attrbuf == NULL) {
359 err = -ENOMEM;
360 goto errout_locked;
361 }
362 } else
363 family->attrbuf = NULL;
364
365 family->id = idr_alloc(&genl_fam_idr, family,
366 start, end + 1, GFP_KERNEL);
367 if (family->id < 0) {
368 err = family->id;
369 goto errout_free;
370 }
371
372 err = genl_validate_assign_mc_groups(family);
373 if (err)
374 goto errout_remove;
375
376 genl_unlock_all();
377
378 /* send all events */
379 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
380 for (i = 0; i < family->n_mcgrps; i++)
381 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
382 &family->mcgrps[i], family->mcgrp_offset + i);
383
384 return 0;
385
386 errout_remove:
387 idr_remove(&genl_fam_idr, family->id);
388 errout_free:
389 kfree(family->attrbuf);
390 errout_locked:
391 genl_unlock_all();
392 return err;
393 }
394 EXPORT_SYMBOL(genl_register_family);
395
396 /**
397 * genl_unregister_family - unregister generic netlink family
398 * @family: generic netlink family
399 *
400 * Unregisters the specified family.
401 *
402 * Returns 0 on success or a negative error code.
403 */
404 int genl_unregister_family(const struct genl_family *family)
405 {
406 genl_lock_all();
407
408 if (!genl_family_find_byid(family->id)) {
409 genl_unlock_all();
410 return -ENOENT;
411 }
412
413 genl_unregister_mc_groups(family);
414
415 idr_remove(&genl_fam_idr, family->id);
416
417 up_write(&cb_lock);
418 wait_event(genl_sk_destructing_waitq,
419 atomic_read(&genl_sk_destructing_cnt) == 0);
420 genl_unlock();
421
422 kfree(family->attrbuf);
423
424 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
425
426 return 0;
427 }
428 EXPORT_SYMBOL(genl_unregister_family);
429
430 /**
431 * genlmsg_put - Add generic netlink header to netlink message
432 * @skb: socket buffer holding the message
433 * @portid: netlink portid the message is addressed to
434 * @seq: sequence number (usually the one of the sender)
435 * @family: generic netlink family
436 * @flags: netlink message flags
437 * @cmd: generic netlink command
438 *
439 * Returns pointer to user specific header
440 */
441 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
442 const struct genl_family *family, int flags, u8 cmd)
443 {
444 struct nlmsghdr *nlh;
445 struct genlmsghdr *hdr;
446
447 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
448 family->hdrsize, flags);
449 if (nlh == NULL)
450 return NULL;
451
452 hdr = nlmsg_data(nlh);
453 hdr->cmd = cmd;
454 hdr->version = family->version;
455 hdr->reserved = 0;
456
457 return (char *) hdr + GENL_HDRLEN;
458 }
459 EXPORT_SYMBOL(genlmsg_put);
460
461 static int genl_lock_start(struct netlink_callback *cb)
462 {
463 /* our ops are always const - netlink API doesn't propagate that */
464 const struct genl_ops *ops = cb->data;
465 int rc = 0;
466
467 if (ops->start) {
468 genl_lock();
469 rc = ops->start(cb);
470 genl_unlock();
471 }
472 return rc;
473 }
474
475 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
476 {
477 /* our ops are always const - netlink API doesn't propagate that */
478 const struct genl_ops *ops = cb->data;
479 int rc;
480
481 genl_lock();
482 rc = ops->dumpit(skb, cb);
483 genl_unlock();
484 return rc;
485 }
486
487 static int genl_lock_done(struct netlink_callback *cb)
488 {
489 /* our ops are always const - netlink API doesn't propagate that */
490 const struct genl_ops *ops = cb->data;
491 int rc = 0;
492
493 if (ops->done) {
494 genl_lock();
495 rc = ops->done(cb);
496 genl_unlock();
497 }
498 return rc;
499 }
500
501 static int genl_family_rcv_msg(const struct genl_family *family,
502 struct sk_buff *skb,
503 struct nlmsghdr *nlh,
504 struct netlink_ext_ack *extack)
505 {
506 const struct genl_ops *ops;
507 struct net *net = sock_net(skb->sk);
508 struct genl_info info;
509 struct genlmsghdr *hdr = nlmsg_data(nlh);
510 struct nlattr **attrbuf;
511 int hdrlen, err;
512
513 /* this family doesn't exist in this netns */
514 if (!family->netnsok && !net_eq(net, &init_net))
515 return -ENOENT;
516
517 hdrlen = GENL_HDRLEN + family->hdrsize;
518 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
519 return -EINVAL;
520
521 ops = genl_get_cmd(hdr->cmd, family);
522 if (ops == NULL)
523 return -EOPNOTSUPP;
524
525 if ((ops->flags & GENL_ADMIN_PERM) &&
526 !netlink_capable(skb, CAP_NET_ADMIN))
527 return -EPERM;
528
529 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
530 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
531 return -EPERM;
532
533 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
534 int rc;
535
536 if (ops->dumpit == NULL)
537 return -EOPNOTSUPP;
538
539 if (!family->parallel_ops) {
540 struct netlink_dump_control c = {
541 .module = family->module,
542 /* we have const, but the netlink API doesn't */
543 .data = (void *)ops,
544 .start = genl_lock_start,
545 .dump = genl_lock_dumpit,
546 .done = genl_lock_done,
547 };
548
549 genl_unlock();
550 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
551 genl_lock();
552
553 } else {
554 struct netlink_dump_control c = {
555 .module = family->module,
556 .start = ops->start,
557 .dump = ops->dumpit,
558 .done = ops->done,
559 };
560
561 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
562 }
563
564 return rc;
565 }
566
567 if (ops->doit == NULL)
568 return -EOPNOTSUPP;
569
570 if (family->maxattr && family->parallel_ops) {
571 attrbuf = kmalloc_array(family->maxattr + 1,
572 sizeof(struct nlattr *),
573 GFP_KERNEL);
574 if (attrbuf == NULL)
575 return -ENOMEM;
576 } else
577 attrbuf = family->attrbuf;
578
579 if (attrbuf) {
580 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
581 ops->policy, extack);
582 if (err < 0)
583 goto out;
584 }
585
586 info.snd_seq = nlh->nlmsg_seq;
587 info.snd_portid = NETLINK_CB(skb).portid;
588 info.nlhdr = nlh;
589 info.genlhdr = nlmsg_data(nlh);
590 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
591 info.attrs = attrbuf;
592 info.extack = extack;
593 genl_info_net_set(&info, net);
594 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
595
596 if (family->pre_doit) {
597 err = family->pre_doit(ops, skb, &info);
598 if (err)
599 goto out;
600 }
601
602 err = ops->doit(skb, &info);
603
604 if (family->post_doit)
605 family->post_doit(ops, skb, &info);
606
607 out:
608 if (family->parallel_ops)
609 kfree(attrbuf);
610
611 return err;
612 }
613
614 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
615 struct netlink_ext_ack *extack)
616 {
617 const struct genl_family *family;
618 int err;
619
620 family = genl_family_find_byid(nlh->nlmsg_type);
621 if (family == NULL)
622 return -ENOENT;
623
624 if (!family->parallel_ops)
625 genl_lock();
626
627 err = genl_family_rcv_msg(family, skb, nlh, extack);
628
629 if (!family->parallel_ops)
630 genl_unlock();
631
632 return err;
633 }
634
635 static void genl_rcv(struct sk_buff *skb)
636 {
637 down_read(&cb_lock);
638 netlink_rcv_skb(skb, &genl_rcv_msg);
639 up_read(&cb_lock);
640 }
641
642 /**************************************************************************
643 * Controller
644 **************************************************************************/
645
646 static struct genl_family genl_ctrl;
647
648 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
649 u32 flags, struct sk_buff *skb, u8 cmd)
650 {
651 void *hdr;
652
653 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
654 if (hdr == NULL)
655 return -1;
656
657 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
658 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
659 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
660 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
661 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
662 goto nla_put_failure;
663
664 if (family->n_ops) {
665 struct nlattr *nla_ops;
666 int i;
667
668 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
669 if (nla_ops == NULL)
670 goto nla_put_failure;
671
672 for (i = 0; i < family->n_ops; i++) {
673 struct nlattr *nest;
674 const struct genl_ops *ops = &family->ops[i];
675 u32 op_flags = ops->flags;
676
677 if (ops->dumpit)
678 op_flags |= GENL_CMD_CAP_DUMP;
679 if (ops->doit)
680 op_flags |= GENL_CMD_CAP_DO;
681 if (ops->policy)
682 op_flags |= GENL_CMD_CAP_HASPOL;
683
684 nest = nla_nest_start(skb, i + 1);
685 if (nest == NULL)
686 goto nla_put_failure;
687
688 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
689 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
690 goto nla_put_failure;
691
692 nla_nest_end(skb, nest);
693 }
694
695 nla_nest_end(skb, nla_ops);
696 }
697
698 if (family->n_mcgrps) {
699 struct nlattr *nla_grps;
700 int i;
701
702 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
703 if (nla_grps == NULL)
704 goto nla_put_failure;
705
706 for (i = 0; i < family->n_mcgrps; i++) {
707 struct nlattr *nest;
708 const struct genl_multicast_group *grp;
709
710 grp = &family->mcgrps[i];
711
712 nest = nla_nest_start(skb, i + 1);
713 if (nest == NULL)
714 goto nla_put_failure;
715
716 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
717 family->mcgrp_offset + i) ||
718 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
719 grp->name))
720 goto nla_put_failure;
721
722 nla_nest_end(skb, nest);
723 }
724 nla_nest_end(skb, nla_grps);
725 }
726
727 genlmsg_end(skb, hdr);
728 return 0;
729
730 nla_put_failure:
731 genlmsg_cancel(skb, hdr);
732 return -EMSGSIZE;
733 }
734
735 static int ctrl_fill_mcgrp_info(const struct genl_family *family,
736 const struct genl_multicast_group *grp,
737 int grp_id, u32 portid, u32 seq, u32 flags,
738 struct sk_buff *skb, u8 cmd)
739 {
740 void *hdr;
741 struct nlattr *nla_grps;
742 struct nlattr *nest;
743
744 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
745 if (hdr == NULL)
746 return -1;
747
748 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
749 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
750 goto nla_put_failure;
751
752 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
753 if (nla_grps == NULL)
754 goto nla_put_failure;
755
756 nest = nla_nest_start(skb, 1);
757 if (nest == NULL)
758 goto nla_put_failure;
759
760 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
761 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
762 grp->name))
763 goto nla_put_failure;
764
765 nla_nest_end(skb, nest);
766 nla_nest_end(skb, nla_grps);
767
768 genlmsg_end(skb, hdr);
769 return 0;
770
771 nla_put_failure:
772 genlmsg_cancel(skb, hdr);
773 return -EMSGSIZE;
774 }
775
776 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
777 {
778 int n = 0;
779 struct genl_family *rt;
780 struct net *net = sock_net(skb->sk);
781 int fams_to_skip = cb->args[0];
782 unsigned int id;
783
784 idr_for_each_entry(&genl_fam_idr, rt, id) {
785 if (!rt->netnsok && !net_eq(net, &init_net))
786 continue;
787
788 if (n++ < fams_to_skip)
789 continue;
790
791 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
792 cb->nlh->nlmsg_seq, NLM_F_MULTI,
793 skb, CTRL_CMD_NEWFAMILY) < 0) {
794 n--;
795 break;
796 }
797 }
798
799 cb->args[0] = n;
800 return skb->len;
801 }
802
803 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
804 u32 portid, int seq, u8 cmd)
805 {
806 struct sk_buff *skb;
807 int err;
808
809 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
810 if (skb == NULL)
811 return ERR_PTR(-ENOBUFS);
812
813 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
814 if (err < 0) {
815 nlmsg_free(skb);
816 return ERR_PTR(err);
817 }
818
819 return skb;
820 }
821
822 static struct sk_buff *
823 ctrl_build_mcgrp_msg(const struct genl_family *family,
824 const struct genl_multicast_group *grp,
825 int grp_id, u32 portid, int seq, u8 cmd)
826 {
827 struct sk_buff *skb;
828 int err;
829
830 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
831 if (skb == NULL)
832 return ERR_PTR(-ENOBUFS);
833
834 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
835 seq, 0, skb, cmd);
836 if (err < 0) {
837 nlmsg_free(skb);
838 return ERR_PTR(err);
839 }
840
841 return skb;
842 }
843
844 static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
845 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
846 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
847 .len = GENL_NAMSIZ - 1 },
848 };
849
850 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
851 {
852 struct sk_buff *msg;
853 const struct genl_family *res = NULL;
854 int err = -EINVAL;
855
856 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
857 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
858 res = genl_family_find_byid(id);
859 err = -ENOENT;
860 }
861
862 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
863 char *name;
864
865 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
866 res = genl_family_find_byname(name);
867 #ifdef CONFIG_MODULES
868 if (res == NULL) {
869 genl_unlock();
870 up_read(&cb_lock);
871 request_module("net-pf-%d-proto-%d-family-%s",
872 PF_NETLINK, NETLINK_GENERIC, name);
873 down_read(&cb_lock);
874 genl_lock();
875 res = genl_family_find_byname(name);
876 }
877 #endif
878 err = -ENOENT;
879 }
880
881 if (res == NULL)
882 return err;
883
884 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
885 /* family doesn't exist here */
886 return -ENOENT;
887 }
888
889 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
890 CTRL_CMD_NEWFAMILY);
891 if (IS_ERR(msg))
892 return PTR_ERR(msg);
893
894 return genlmsg_reply(msg, info);
895 }
896
897 static int genl_ctrl_event(int event, const struct genl_family *family,
898 const struct genl_multicast_group *grp,
899 int grp_id)
900 {
901 struct sk_buff *msg;
902
903 /* genl is still initialising */
904 if (!init_net.genl_sock)
905 return 0;
906
907 switch (event) {
908 case CTRL_CMD_NEWFAMILY:
909 case CTRL_CMD_DELFAMILY:
910 WARN_ON(grp);
911 msg = ctrl_build_family_msg(family, 0, 0, event);
912 break;
913 case CTRL_CMD_NEWMCAST_GRP:
914 case CTRL_CMD_DELMCAST_GRP:
915 BUG_ON(!grp);
916 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
917 break;
918 default:
919 return -EINVAL;
920 }
921
922 if (IS_ERR(msg))
923 return PTR_ERR(msg);
924
925 if (!family->netnsok) {
926 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
927 0, GFP_KERNEL);
928 } else {
929 rcu_read_lock();
930 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
931 0, GFP_ATOMIC);
932 rcu_read_unlock();
933 }
934
935 return 0;
936 }
937
938 static const struct genl_ops genl_ctrl_ops[] = {
939 {
940 .cmd = CTRL_CMD_GETFAMILY,
941 .doit = ctrl_getfamily,
942 .dumpit = ctrl_dumpfamily,
943 .policy = ctrl_policy,
944 },
945 };
946
947 static const struct genl_multicast_group genl_ctrl_groups[] = {
948 { .name = "notify", },
949 };
950
951 static struct genl_family genl_ctrl __ro_after_init = {
952 .module = THIS_MODULE,
953 .ops = genl_ctrl_ops,
954 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
955 .mcgrps = genl_ctrl_groups,
956 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
957 .id = GENL_ID_CTRL,
958 .name = "nlctrl",
959 .version = 0x2,
960 .maxattr = CTRL_ATTR_MAX,
961 .netnsok = true,
962 };
963
964 static int genl_bind(struct net *net, int group)
965 {
966 struct genl_family *f;
967 int err = -ENOENT;
968 unsigned int id;
969
970 down_read(&cb_lock);
971
972 idr_for_each_entry(&genl_fam_idr, f, id) {
973 if (group >= f->mcgrp_offset &&
974 group < f->mcgrp_offset + f->n_mcgrps) {
975 int fam_grp = group - f->mcgrp_offset;
976
977 if (!f->netnsok && net != &init_net)
978 err = -ENOENT;
979 else if (f->mcast_bind)
980 err = f->mcast_bind(net, fam_grp);
981 else
982 err = 0;
983 break;
984 }
985 }
986 up_read(&cb_lock);
987
988 return err;
989 }
990
991 static void genl_unbind(struct net *net, int group)
992 {
993 struct genl_family *f;
994 unsigned int id;
995
996 down_read(&cb_lock);
997
998 idr_for_each_entry(&genl_fam_idr, f, id) {
999 if (group >= f->mcgrp_offset &&
1000 group < f->mcgrp_offset + f->n_mcgrps) {
1001 int fam_grp = group - f->mcgrp_offset;
1002
1003 if (f->mcast_unbind)
1004 f->mcast_unbind(net, fam_grp);
1005 break;
1006 }
1007 }
1008 up_read(&cb_lock);
1009 }
1010
1011 static int __net_init genl_pernet_init(struct net *net)
1012 {
1013 struct netlink_kernel_cfg cfg = {
1014 .input = genl_rcv,
1015 .flags = NL_CFG_F_NONROOT_RECV,
1016 .bind = genl_bind,
1017 .unbind = genl_unbind,
1018 };
1019
1020 /* we'll bump the group number right afterwards */
1021 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1022
1023 if (!net->genl_sock && net_eq(net, &init_net))
1024 panic("GENL: Cannot initialize generic netlink\n");
1025
1026 if (!net->genl_sock)
1027 return -ENOMEM;
1028
1029 return 0;
1030 }
1031
1032 static void __net_exit genl_pernet_exit(struct net *net)
1033 {
1034 netlink_kernel_release(net->genl_sock);
1035 net->genl_sock = NULL;
1036 }
1037
1038 static struct pernet_operations genl_pernet_ops = {
1039 .init = genl_pernet_init,
1040 .exit = genl_pernet_exit,
1041 };
1042
1043 static int __init genl_init(void)
1044 {
1045 int err;
1046
1047 err = genl_register_family(&genl_ctrl);
1048 if (err < 0)
1049 goto problem;
1050
1051 err = register_pernet_subsys(&genl_pernet_ops);
1052 if (err)
1053 goto problem;
1054
1055 return 0;
1056
1057 problem:
1058 panic("GENL: Cannot register controller: %d\n", err);
1059 }
1060
1061 subsys_initcall(genl_init);
1062
1063 /**
1064 * genl_family_attrbuf - return family's attrbuf
1065 * @family: the family
1066 *
1067 * Return the family's attrbuf, while validating that it's
1068 * actually valid to access it.
1069 *
1070 * You cannot use this function with a family that has parallel_ops
1071 * and you can only use it within (pre/post) doit/dumpit callbacks.
1072 */
1073 struct nlattr **genl_family_attrbuf(const struct genl_family *family)
1074 {
1075 if (!WARN_ON(family->parallel_ops))
1076 lockdep_assert_held(&genl_mutex);
1077
1078 return family->attrbuf;
1079 }
1080 EXPORT_SYMBOL(genl_family_attrbuf);
1081
1082 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1083 gfp_t flags)
1084 {
1085 struct sk_buff *tmp;
1086 struct net *net, *prev = NULL;
1087 bool delivered = false;
1088 int err;
1089
1090 for_each_net_rcu(net) {
1091 if (prev) {
1092 tmp = skb_clone(skb, flags);
1093 if (!tmp) {
1094 err = -ENOMEM;
1095 goto error;
1096 }
1097 err = nlmsg_multicast(prev->genl_sock, tmp,
1098 portid, group, flags);
1099 if (!err)
1100 delivered = true;
1101 else if (err != -ESRCH)
1102 goto error;
1103 }
1104
1105 prev = net;
1106 }
1107
1108 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1109 if (!err)
1110 delivered = true;
1111 else if (err != -ESRCH)
1112 return err;
1113 return delivered ? 0 : -ESRCH;
1114 error:
1115 kfree_skb(skb);
1116 return err;
1117 }
1118
1119 int genlmsg_multicast_allns(const struct genl_family *family,
1120 struct sk_buff *skb, u32 portid,
1121 unsigned int group, gfp_t flags)
1122 {
1123 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1124 return -EINVAL;
1125 group = family->mcgrp_offset + group;
1126 return genlmsg_mcast(skb, portid, group, flags);
1127 }
1128 EXPORT_SYMBOL(genlmsg_multicast_allns);
1129
1130 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1131 struct genl_info *info, u32 group, gfp_t flags)
1132 {
1133 struct net *net = genl_info_net(info);
1134 struct sock *sk = net->genl_sock;
1135 int report = 0;
1136
1137 if (info->nlhdr)
1138 report = nlmsg_report(info->nlhdr);
1139
1140 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1141 return;
1142 group = family->mcgrp_offset + group;
1143 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1144 }
1145 EXPORT_SYMBOL(genl_notify);
Linux with added FPC-III support