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1/*
2 * NETLINK Generic Netlink Family
3 *
4 * Authors: Jamal Hadi Salim
5 * Thomas Graf <tgraf@suug.ch>
6 * Johannes Berg <johannes@sipsolutions.net>
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/string.h>
16#include <linux/skbuff.h>
17#include <linux/mutex.h>
18#include <linux/bitmap.h>
19#include <linux/rwsem.h>
20#include <net/sock.h>
21#include <net/genetlink.h>
22
23static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
24static DECLARE_RWSEM(cb_lock);
25
26atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
27DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
28
29void genl_lock(void)
30{
31 mutex_lock(&genl_mutex);
32}
33EXPORT_SYMBOL(genl_lock);
34
35void genl_unlock(void)
36{
37 mutex_unlock(&genl_mutex);
38}
39EXPORT_SYMBOL(genl_unlock);
40
41#ifdef CONFIG_LOCKDEP
42bool lockdep_genl_is_held(void)
43{
44 return lockdep_is_held(&genl_mutex);
45}
46EXPORT_SYMBOL(lockdep_genl_is_held);
47#endif
48
49static void genl_lock_all(void)
50{
51 down_write(&cb_lock);
52 genl_lock();
53}
54
55static void genl_unlock_all(void)
56{
57 genl_unlock();
58 up_write(&cb_lock);
59}
60
61#define GENL_FAM_TAB_SIZE 16
62#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
63
64static struct list_head family_ht[GENL_FAM_TAB_SIZE];
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, struct genl_family *family,
90 const struct genl_multicast_group *grp,
91 int grp_id);
92
93static inline unsigned int genl_family_hash(unsigned int id)
94{
95 return id & GENL_FAM_TAB_MASK;
96}
97
98static inline struct list_head *genl_family_chain(unsigned int id)
99{
100 return &family_ht[genl_family_hash(id)];
101}
102
103static struct genl_family *genl_family_find_byid(unsigned int id)
104{
105 struct genl_family *f;
106
107 list_for_each_entry(f, genl_family_chain(id), family_list)
108 if (f->id == id)
109 return f;
110
111 return NULL;
112}
113
114static struct genl_family *genl_family_find_byname(char *name)
115{
116 struct genl_family *f;
117 int i;
118
119 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
120 list_for_each_entry(f, genl_family_chain(i), family_list)
121 if (strcmp(f->name, name) == 0)
122 return f;
123
124 return NULL;
125}
126
127static const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
128{
129 int i;
130
131 for (i = 0; i < family->n_ops; i++)
132 if (family->ops[i].cmd == cmd)
133 return &family->ops[i];
134
135 return NULL;
136}
137
138/* Of course we are going to have problems once we hit
139 * 2^16 alive types, but that can only happen by year 2K
140*/
141static u16 genl_generate_id(void)
142{
143 static u16 id_gen_idx = GENL_MIN_ID;
144 int i;
145
146 for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
147 if (id_gen_idx != GENL_ID_VFS_DQUOT &&
148 id_gen_idx != GENL_ID_PMCRAID &&
149 !genl_family_find_byid(id_gen_idx))
150 return id_gen_idx;
151 if (++id_gen_idx > GENL_MAX_ID)
152 id_gen_idx = GENL_MIN_ID;
153 }
154
155 return 0;
156}
157
158static int genl_allocate_reserve_groups(int n_groups, int *first_id)
159{
160 unsigned long *new_groups;
161 int start = 0;
162 int i;
163 int id;
164 bool fits;
165
166 do {
167 if (start == 0)
168 id = find_first_zero_bit(mc_groups,
169 mc_groups_longs *
170 BITS_PER_LONG);
171 else
172 id = find_next_zero_bit(mc_groups,
173 mc_groups_longs * BITS_PER_LONG,
174 start);
175
176 fits = true;
177 for (i = id;
178 i < min_t(int, id + n_groups,
179 mc_groups_longs * BITS_PER_LONG);
180 i++) {
181 if (test_bit(i, mc_groups)) {
182 start = i;
183 fits = false;
184 break;
185 }
186 }
187
188 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
189 unsigned long new_longs = mc_groups_longs +
190 BITS_TO_LONGS(n_groups);
191 size_t nlen = new_longs * sizeof(unsigned long);
192
193 if (mc_groups == &mc_group_start) {
194 new_groups = kzalloc(nlen, GFP_KERNEL);
195 if (!new_groups)
196 return -ENOMEM;
197 mc_groups = new_groups;
198 *mc_groups = mc_group_start;
199 } else {
200 new_groups = krealloc(mc_groups, nlen,
201 GFP_KERNEL);
202 if (!new_groups)
203 return -ENOMEM;
204 mc_groups = new_groups;
205 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
206 mc_groups[mc_groups_longs + i] = 0;
207 }
208 mc_groups_longs = new_longs;
209 }
210 } while (!fits);
211
212 for (i = id; i < id + n_groups; i++)
213 set_bit(i, mc_groups);
214 *first_id = id;
215 return 0;
216}
217
218static struct genl_family genl_ctrl;
219
220static int genl_validate_assign_mc_groups(struct genl_family *family)
221{
222 int first_id;
223 int n_groups = family->n_mcgrps;
224 int err = 0, i;
225 bool groups_allocated = false;
226
227 if (!n_groups)
228 return 0;
229
230 for (i = 0; i < n_groups; i++) {
231 const struct genl_multicast_group *grp = &family->mcgrps[i];
232
233 if (WARN_ON(grp->name[0] == '\0'))
234 return -EINVAL;
235 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
236 return -EINVAL;
237 }
238
239 /* special-case our own group and hacks */
240 if (family == &genl_ctrl) {
241 first_id = GENL_ID_CTRL;
242 BUG_ON(n_groups != 1);
243 } else if (strcmp(family->name, "NET_DM") == 0) {
244 first_id = 1;
245 BUG_ON(n_groups != 1);
246 } else if (family->id == GENL_ID_VFS_DQUOT) {
247 first_id = GENL_ID_VFS_DQUOT;
248 BUG_ON(n_groups != 1);
249 } else if (family->id == GENL_ID_PMCRAID) {
250 first_id = GENL_ID_PMCRAID;
251 BUG_ON(n_groups != 1);
252 } else {
253 groups_allocated = true;
254 err = genl_allocate_reserve_groups(n_groups, &first_id);
255 if (err)
256 return err;
257 }
258
259 family->mcgrp_offset = first_id;
260
261 /* if still initializing, can't and don't need to to realloc bitmaps */
262 if (!init_net.genl_sock)
263 return 0;
264
265 if (family->netnsok) {
266 struct net *net;
267
268 netlink_table_grab();
269 rcu_read_lock();
270 for_each_net_rcu(net) {
271 err = __netlink_change_ngroups(net->genl_sock,
272 mc_groups_longs * BITS_PER_LONG);
273 if (err) {
274 /*
275 * No need to roll back, can only fail if
276 * memory allocation fails and then the
277 * number of _possible_ groups has been
278 * increased on some sockets which is ok.
279 */
280 break;
281 }
282 }
283 rcu_read_unlock();
284 netlink_table_ungrab();
285 } else {
286 err = netlink_change_ngroups(init_net.genl_sock,
287 mc_groups_longs * BITS_PER_LONG);
288 }
289
290 if (groups_allocated && err) {
291 for (i = 0; i < family->n_mcgrps; i++)
292 clear_bit(family->mcgrp_offset + i, mc_groups);
293 }
294
295 return err;
296}
297
298static void genl_unregister_mc_groups(struct genl_family *family)
299{
300 struct net *net;
301 int i;
302
303 netlink_table_grab();
304 rcu_read_lock();
305 for_each_net_rcu(net) {
306 for (i = 0; i < family->n_mcgrps; i++)
307 __netlink_clear_multicast_users(
308 net->genl_sock, family->mcgrp_offset + i);
309 }
310 rcu_read_unlock();
311 netlink_table_ungrab();
312
313 for (i = 0; i < family->n_mcgrps; i++) {
314 int grp_id = family->mcgrp_offset + i;
315
316 if (grp_id != 1)
317 clear_bit(grp_id, mc_groups);
318 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
319 &family->mcgrps[i], grp_id);
320 }
321}
322
323static int genl_validate_ops(const struct genl_family *family)
324{
325 const struct genl_ops *ops = family->ops;
326 unsigned int n_ops = family->n_ops;
327 int i, j;
328
329 if (WARN_ON(n_ops && !ops))
330 return -EINVAL;
331
332 if (!n_ops)
333 return 0;
334
335 for (i = 0; i < n_ops; i++) {
336 if (ops[i].dumpit == NULL && ops[i].doit == NULL)
337 return -EINVAL;
338 for (j = i + 1; j < n_ops; j++)
339 if (ops[i].cmd == ops[j].cmd)
340 return -EINVAL;
341 }
342
343 return 0;
344}
345
346/**
347 * __genl_register_family - register a generic netlink family
348 * @family: generic netlink family
349 *
350 * Registers the specified family after validating it first. Only one
351 * family may be registered with the same family name or identifier.
352 * The family id may equal GENL_ID_GENERATE causing an unique id to
353 * be automatically generated and assigned.
354 *
355 * The family's ops array must already be assigned, you can use the
356 * genl_register_family_with_ops() helper function.
357 *
358 * Return 0 on success or a negative error code.
359 */
360int __genl_register_family(struct genl_family *family)
361{
362 int err = -EINVAL, i;
363
364 if (family->id && family->id < GENL_MIN_ID)
365 goto errout;
366
367 if (family->id > GENL_MAX_ID)
368 goto errout;
369
370 err = genl_validate_ops(family);
371 if (err)
372 return err;
373
374 genl_lock_all();
375
376 if (genl_family_find_byname(family->name)) {
377 err = -EEXIST;
378 goto errout_locked;
379 }
380
381 if (family->id == GENL_ID_GENERATE) {
382 u16 newid = genl_generate_id();
383
384 if (!newid) {
385 err = -ENOMEM;
386 goto errout_locked;
387 }
388
389 family->id = newid;
390 } else if (genl_family_find_byid(family->id)) {
391 err = -EEXIST;
392 goto errout_locked;
393 }
394
395 if (family->maxattr && !family->parallel_ops) {
396 family->attrbuf = kmalloc((family->maxattr+1) *
397 sizeof(struct nlattr *), GFP_KERNEL);
398 if (family->attrbuf == NULL) {
399 err = -ENOMEM;
400 goto errout_locked;
401 }
402 } else
403 family->attrbuf = NULL;
404
405 err = genl_validate_assign_mc_groups(family);
406 if (err)
407 goto errout_locked;
408
409 list_add_tail(&family->family_list, genl_family_chain(family->id));
410 genl_unlock_all();
411
412 /* send all events */
413 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
414 for (i = 0; i < family->n_mcgrps; i++)
415 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
416 &family->mcgrps[i], family->mcgrp_offset + i);
417
418 return 0;
419
420errout_locked:
421 genl_unlock_all();
422errout:
423 return err;
424}
425EXPORT_SYMBOL(__genl_register_family);
426
427/**
428 * genl_unregister_family - unregister generic netlink family
429 * @family: generic netlink family
430 *
431 * Unregisters the specified family.
432 *
433 * Returns 0 on success or a negative error code.
434 */
435int genl_unregister_family(struct genl_family *family)
436{
437 struct genl_family *rc;
438
439 genl_lock_all();
440
441 list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
442 if (family->id != rc->id || strcmp(rc->name, family->name))
443 continue;
444
445 genl_unregister_mc_groups(family);
446
447 list_del(&rc->family_list);
448 family->n_ops = 0;
449 up_write(&cb_lock);
450 wait_event(genl_sk_destructing_waitq,
451 atomic_read(&genl_sk_destructing_cnt) == 0);
452 genl_unlock();
453
454 kfree(family->attrbuf);
455 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
456 return 0;
457 }
458
459 genl_unlock_all();
460
461 return -ENOENT;
462}
463EXPORT_SYMBOL(genl_unregister_family);
464
465/**
466 * genlmsg_put - Add generic netlink header to netlink message
467 * @skb: socket buffer holding the message
468 * @portid: netlink portid the message is addressed to
469 * @seq: sequence number (usually the one of the sender)
470 * @family: generic netlink family
471 * @flags: netlink message flags
472 * @cmd: generic netlink command
473 *
474 * Returns pointer to user specific header
475 */
476void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
477 struct genl_family *family, int flags, u8 cmd)
478{
479 struct nlmsghdr *nlh;
480 struct genlmsghdr *hdr;
481
482 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
483 family->hdrsize, flags);
484 if (nlh == NULL)
485 return NULL;
486
487 hdr = nlmsg_data(nlh);
488 hdr->cmd = cmd;
489 hdr->version = family->version;
490 hdr->reserved = 0;
491
492 return (char *) hdr + GENL_HDRLEN;
493}
494EXPORT_SYMBOL(genlmsg_put);
495
496static int genl_lock_start(struct netlink_callback *cb)
497{
498 /* our ops are always const - netlink API doesn't propagate that */
499 const struct genl_ops *ops = cb->data;
500 int rc = 0;
501
502 if (ops->start) {
503 genl_lock();
504 rc = ops->start(cb);
505 genl_unlock();
506 }
507 return rc;
508}
509
510static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
511{
512 /* our ops are always const - netlink API doesn't propagate that */
513 const struct genl_ops *ops = cb->data;
514 int rc;
515
516 genl_lock();
517 rc = ops->dumpit(skb, cb);
518 genl_unlock();
519 return rc;
520}
521
522static int genl_lock_done(struct netlink_callback *cb)
523{
524 /* our ops are always const - netlink API doesn't propagate that */
525 const struct genl_ops *ops = cb->data;
526 int rc = 0;
527
528 if (ops->done) {
529 genl_lock();
530 rc = ops->done(cb);
531 genl_unlock();
532 }
533 return rc;
534}
535
536static int genl_family_rcv_msg(struct genl_family *family,
537 struct sk_buff *skb,
538 struct nlmsghdr *nlh)
539{
540 const struct genl_ops *ops;
541 struct net *net = sock_net(skb->sk);
542 struct genl_info info;
543 struct genlmsghdr *hdr = nlmsg_data(nlh);
544 struct nlattr **attrbuf;
545 int hdrlen, err;
546
547 /* this family doesn't exist in this netns */
548 if (!family->netnsok && !net_eq(net, &init_net))
549 return -ENOENT;
550
551 hdrlen = GENL_HDRLEN + family->hdrsize;
552 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
553 return -EINVAL;
554
555 ops = genl_get_cmd(hdr->cmd, family);
556 if (ops == NULL)
557 return -EOPNOTSUPP;
558
559 if ((ops->flags & GENL_ADMIN_PERM) &&
560 !netlink_capable(skb, CAP_NET_ADMIN))
561 return -EPERM;
562
563 if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
564 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
565 return -EPERM;
566
567 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
568 int rc;
569
570 if (ops->dumpit == NULL)
571 return -EOPNOTSUPP;
572
573 if (!family->parallel_ops) {
574 struct netlink_dump_control c = {
575 .module = family->module,
576 /* we have const, but the netlink API doesn't */
577 .data = (void *)ops,
578 .start = genl_lock_start,
579 .dump = genl_lock_dumpit,
580 .done = genl_lock_done,
581 };
582
583 genl_unlock();
584 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
585 genl_lock();
586
587 } else {
588 struct netlink_dump_control c = {
589 .module = family->module,
590 .start = ops->start,
591 .dump = ops->dumpit,
592 .done = ops->done,
593 };
594
595 rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
596 }
597
598 return rc;
599 }
600
601 if (ops->doit == NULL)
602 return -EOPNOTSUPP;
603
604 if (family->maxattr && family->parallel_ops) {
605 attrbuf = kmalloc((family->maxattr+1) *
606 sizeof(struct nlattr *), GFP_KERNEL);
607 if (attrbuf == NULL)
608 return -ENOMEM;
609 } else
610 attrbuf = family->attrbuf;
611
612 if (attrbuf) {
613 err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
614 ops->policy);
615 if (err < 0)
616 goto out;
617 }
618
619 info.snd_seq = nlh->nlmsg_seq;
620 info.snd_portid = NETLINK_CB(skb).portid;
621 info.nlhdr = nlh;
622 info.genlhdr = nlmsg_data(nlh);
623 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
624 info.attrs = attrbuf;
625 genl_info_net_set(&info, net);
626 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
627
628 if (family->pre_doit) {
629 err = family->pre_doit(ops, skb, &info);
630 if (err)
631 goto out;
632 }
633
634 err = ops->doit(skb, &info);
635
636 if (family->post_doit)
637 family->post_doit(ops, skb, &info);
638
639out:
640 if (family->parallel_ops)
641 kfree(attrbuf);
642
643 return err;
644}
645
646static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
647{
648 struct genl_family *family;
649 int err;
650
651 family = genl_family_find_byid(nlh->nlmsg_type);
652 if (family == NULL)
653 return -ENOENT;
654
655 if (!family->parallel_ops)
656 genl_lock();
657
658 err = genl_family_rcv_msg(family, skb, nlh);
659
660 if (!family->parallel_ops)
661 genl_unlock();
662
663 return err;
664}
665
666static void genl_rcv(struct sk_buff *skb)
667{
668 down_read(&cb_lock);
669 netlink_rcv_skb(skb, &genl_rcv_msg);
670 up_read(&cb_lock);
671}
672
673/**************************************************************************
674 * Controller
675 **************************************************************************/
676
677static struct genl_family genl_ctrl = {
678 .id = GENL_ID_CTRL,
679 .name = "nlctrl",
680 .version = 0x2,
681 .maxattr = CTRL_ATTR_MAX,
682 .netnsok = true,
683};
684
685static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
686 u32 flags, struct sk_buff *skb, u8 cmd)
687{
688 void *hdr;
689
690 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
691 if (hdr == NULL)
692 return -1;
693
694 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
695 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
696 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
697 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
698 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
699 goto nla_put_failure;
700
701 if (family->n_ops) {
702 struct nlattr *nla_ops;
703 int i;
704
705 nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
706 if (nla_ops == NULL)
707 goto nla_put_failure;
708
709 for (i = 0; i < family->n_ops; i++) {
710 struct nlattr *nest;
711 const struct genl_ops *ops = &family->ops[i];
712 u32 op_flags = ops->flags;
713
714 if (ops->dumpit)
715 op_flags |= GENL_CMD_CAP_DUMP;
716 if (ops->doit)
717 op_flags |= GENL_CMD_CAP_DO;
718 if (ops->policy)
719 op_flags |= GENL_CMD_CAP_HASPOL;
720
721 nest = nla_nest_start(skb, i + 1);
722 if (nest == NULL)
723 goto nla_put_failure;
724
725 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
726 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
727 goto nla_put_failure;
728
729 nla_nest_end(skb, nest);
730 }
731
732 nla_nest_end(skb, nla_ops);
733 }
734
735 if (family->n_mcgrps) {
736 struct nlattr *nla_grps;
737 int i;
738
739 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
740 if (nla_grps == NULL)
741 goto nla_put_failure;
742
743 for (i = 0; i < family->n_mcgrps; i++) {
744 struct nlattr *nest;
745 const struct genl_multicast_group *grp;
746
747 grp = &family->mcgrps[i];
748
749 nest = nla_nest_start(skb, i + 1);
750 if (nest == NULL)
751 goto nla_put_failure;
752
753 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
754 family->mcgrp_offset + i) ||
755 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
756 grp->name))
757 goto nla_put_failure;
758
759 nla_nest_end(skb, nest);
760 }
761 nla_nest_end(skb, nla_grps);
762 }
763
764 genlmsg_end(skb, hdr);
765 return 0;
766
767nla_put_failure:
768 genlmsg_cancel(skb, hdr);
769 return -EMSGSIZE;
770}
771
772static int ctrl_fill_mcgrp_info(struct genl_family *family,
773 const struct genl_multicast_group *grp,
774 int grp_id, u32 portid, u32 seq, u32 flags,
775 struct sk_buff *skb, u8 cmd)
776{
777 void *hdr;
778 struct nlattr *nla_grps;
779 struct nlattr *nest;
780
781 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
782 if (hdr == NULL)
783 return -1;
784
785 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
786 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
787 goto nla_put_failure;
788
789 nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
790 if (nla_grps == NULL)
791 goto nla_put_failure;
792
793 nest = nla_nest_start(skb, 1);
794 if (nest == NULL)
795 goto nla_put_failure;
796
797 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
798 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
799 grp->name))
800 goto nla_put_failure;
801
802 nla_nest_end(skb, nest);
803 nla_nest_end(skb, nla_grps);
804
805 genlmsg_end(skb, hdr);
806 return 0;
807
808nla_put_failure:
809 genlmsg_cancel(skb, hdr);
810 return -EMSGSIZE;
811}
812
813static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
814{
815
816 int i, n = 0;
817 struct genl_family *rt;
818 struct net *net = sock_net(skb->sk);
819 int chains_to_skip = cb->args[0];
820 int fams_to_skip = cb->args[1];
821
822 for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
823 n = 0;
824 list_for_each_entry(rt, genl_family_chain(i), family_list) {
825 if (!rt->netnsok && !net_eq(net, &init_net))
826 continue;
827 if (++n < fams_to_skip)
828 continue;
829 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
830 cb->nlh->nlmsg_seq, NLM_F_MULTI,
831 skb, CTRL_CMD_NEWFAMILY) < 0)
832 goto errout;
833 }
834
835 fams_to_skip = 0;
836 }
837
838errout:
839 cb->args[0] = i;
840 cb->args[1] = n;
841
842 return skb->len;
843}
844
845static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
846 u32 portid, int seq, u8 cmd)
847{
848 struct sk_buff *skb;
849 int err;
850
851 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
852 if (skb == NULL)
853 return ERR_PTR(-ENOBUFS);
854
855 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
856 if (err < 0) {
857 nlmsg_free(skb);
858 return ERR_PTR(err);
859 }
860
861 return skb;
862}
863
864static struct sk_buff *
865ctrl_build_mcgrp_msg(struct genl_family *family,
866 const struct genl_multicast_group *grp,
867 int grp_id, u32 portid, int seq, u8 cmd)
868{
869 struct sk_buff *skb;
870 int err;
871
872 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
873 if (skb == NULL)
874 return ERR_PTR(-ENOBUFS);
875
876 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
877 seq, 0, skb, cmd);
878 if (err < 0) {
879 nlmsg_free(skb);
880 return ERR_PTR(err);
881 }
882
883 return skb;
884}
885
886static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
887 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
888 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
889 .len = GENL_NAMSIZ - 1 },
890};
891
892static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
893{
894 struct sk_buff *msg;
895 struct genl_family *res = NULL;
896 int err = -EINVAL;
897
898 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
899 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
900 res = genl_family_find_byid(id);
901 err = -ENOENT;
902 }
903
904 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
905 char *name;
906
907 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
908 res = genl_family_find_byname(name);
909#ifdef CONFIG_MODULES
910 if (res == NULL) {
911 genl_unlock();
912 up_read(&cb_lock);
913 request_module("net-pf-%d-proto-%d-family-%s",
914 PF_NETLINK, NETLINK_GENERIC, name);
915 down_read(&cb_lock);
916 genl_lock();
917 res = genl_family_find_byname(name);
918 }
919#endif
920 err = -ENOENT;
921 }
922
923 if (res == NULL)
924 return err;
925
926 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
927 /* family doesn't exist here */
928 return -ENOENT;
929 }
930
931 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
932 CTRL_CMD_NEWFAMILY);
933 if (IS_ERR(msg))
934 return PTR_ERR(msg);
935
936 return genlmsg_reply(msg, info);
937}
938
939static int genl_ctrl_event(int event, struct genl_family *family,
940 const struct genl_multicast_group *grp,
941 int grp_id)
942{
943 struct sk_buff *msg;
944
945 /* genl is still initialising */
946 if (!init_net.genl_sock)
947 return 0;
948
949 switch (event) {
950 case CTRL_CMD_NEWFAMILY:
951 case CTRL_CMD_DELFAMILY:
952 WARN_ON(grp);
953 msg = ctrl_build_family_msg(family, 0, 0, event);
954 break;
955 case CTRL_CMD_NEWMCAST_GRP:
956 case CTRL_CMD_DELMCAST_GRP:
957 BUG_ON(!grp);
958 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
959 break;
960 default:
961 return -EINVAL;
962 }
963
964 if (IS_ERR(msg))
965 return PTR_ERR(msg);
966
967 if (!family->netnsok) {
968 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
969 0, GFP_KERNEL);
970 } else {
971 rcu_read_lock();
972 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
973 0, GFP_ATOMIC);
974 rcu_read_unlock();
975 }
976
977 return 0;
978}
979
980static struct genl_ops genl_ctrl_ops[] = {
981 {
982 .cmd = CTRL_CMD_GETFAMILY,
983 .doit = ctrl_getfamily,
984 .dumpit = ctrl_dumpfamily,
985 .policy = ctrl_policy,
986 },
987};
988
989static struct genl_multicast_group genl_ctrl_groups[] = {
990 { .name = "notify", },
991};
992
993static int genl_bind(struct net *net, int group)
994{
995 int i, err = -ENOENT;
996
997 down_read(&cb_lock);
998 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
999 struct genl_family *f;
1000
1001 list_for_each_entry(f, genl_family_chain(i), family_list) {
1002 if (group >= f->mcgrp_offset &&
1003 group < f->mcgrp_offset + f->n_mcgrps) {
1004 int fam_grp = group - f->mcgrp_offset;
1005
1006 if (!f->netnsok && net != &init_net)
1007 err = -ENOENT;
1008 else if (f->mcast_bind)
1009 err = f->mcast_bind(net, fam_grp);
1010 else
1011 err = 0;
1012 break;
1013 }
1014 }
1015 }
1016 up_read(&cb_lock);
1017
1018 return err;
1019}
1020
1021static void genl_unbind(struct net *net, int group)
1022{
1023 int i;
1024
1025 down_read(&cb_lock);
1026 for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
1027 struct genl_family *f;
1028
1029 list_for_each_entry(f, genl_family_chain(i), family_list) {
1030 if (group >= f->mcgrp_offset &&
1031 group < f->mcgrp_offset + f->n_mcgrps) {
1032 int fam_grp = group - f->mcgrp_offset;
1033
1034 if (f->mcast_unbind)
1035 f->mcast_unbind(net, fam_grp);
1036 break;
1037 }
1038 }
1039 }
1040 up_read(&cb_lock);
1041}
1042
1043static int __net_init genl_pernet_init(struct net *net)
1044{
1045 struct netlink_kernel_cfg cfg = {
1046 .input = genl_rcv,
1047 .flags = NL_CFG_F_NONROOT_RECV,
1048 .bind = genl_bind,
1049 .unbind = genl_unbind,
1050 };
1051
1052 /* we'll bump the group number right afterwards */
1053 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1054
1055 if (!net->genl_sock && net_eq(net, &init_net))
1056 panic("GENL: Cannot initialize generic netlink\n");
1057
1058 if (!net->genl_sock)
1059 return -ENOMEM;
1060
1061 return 0;
1062}
1063
1064static void __net_exit genl_pernet_exit(struct net *net)
1065{
1066 netlink_kernel_release(net->genl_sock);
1067 net->genl_sock = NULL;
1068}
1069
1070static struct pernet_operations genl_pernet_ops = {
1071 .init = genl_pernet_init,
1072 .exit = genl_pernet_exit,
1073};
1074
1075static int __init genl_init(void)
1076{
1077 int i, err;
1078
1079 for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
1080 INIT_LIST_HEAD(&family_ht[i]);
1081
1082 err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
1083 genl_ctrl_groups);
1084 if (err < 0)
1085 goto problem;
1086
1087 err = register_pernet_subsys(&genl_pernet_ops);
1088 if (err)
1089 goto problem;
1090
1091 return 0;
1092
1093problem:
1094 panic("GENL: Cannot register controller: %d\n", err);
1095}
1096
1097subsys_initcall(genl_init);
1098
1099static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1100 gfp_t flags)
1101{
1102 struct sk_buff *tmp;
1103 struct net *net, *prev = NULL;
1104 int err;
1105
1106 for_each_net_rcu(net) {
1107 if (prev) {
1108 tmp = skb_clone(skb, flags);
1109 if (!tmp) {
1110 err = -ENOMEM;
1111 goto error;
1112 }
1113 err = nlmsg_multicast(prev->genl_sock, tmp,
1114 portid, group, flags);
1115 if (err)
1116 goto error;
1117 }
1118
1119 prev = net;
1120 }
1121
1122 return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1123 error:
1124 kfree_skb(skb);
1125 return err;
1126}
1127
1128int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
1129 u32 portid, unsigned int group, gfp_t flags)
1130{
1131 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1132 return -EINVAL;
1133 group = family->mcgrp_offset + group;
1134 return genlmsg_mcast(skb, portid, group, flags);
1135}
1136EXPORT_SYMBOL(genlmsg_multicast_allns);
1137
1138void genl_notify(struct genl_family *family, struct sk_buff *skb,
1139 struct genl_info *info, u32 group, gfp_t flags)
1140{
1141 struct net *net = genl_info_net(info);
1142 struct sock *sk = net->genl_sock;
1143 int report = 0;
1144
1145 if (info->nlhdr)
1146 report = nlmsg_report(info->nlhdr);
1147
1148 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1149 return;
1150 group = family->mcgrp_offset + group;
1151 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
1152}
1153EXPORT_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);