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
genl_lock(void)31 void genl_lock(void)
32 {
33 mutex_lock(&genl_mutex);
34 }
35 EXPORT_SYMBOL(genl_lock);
36
genl_unlock(void)37 void genl_unlock(void)
38 {
39 mutex_unlock(&genl_mutex);
40 }
41 EXPORT_SYMBOL(genl_unlock);
42
genl_lock_all(void)43 static void genl_lock_all(void)
44 {
45 down_write(&cb_lock);
46 genl_lock();
47 }
48
genl_unlock_all(void)49 static void genl_unlock_all(void)
50 {
51 genl_unlock();
52 up_write(&cb_lock);
53 }
54
55 static 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 */
75 static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
76 BIT(GENL_ID_VFS_DQUOT) |
77 BIT(GENL_ID_PMCRAID);
78 static unsigned long *mc_groups = &mc_group_start;
79 static unsigned long mc_groups_longs = 1;
80
81 /* We need the last attribute with non-zero ID therefore a 2-entry array */
82 static struct nla_policy genl_policy_reject_all[] = {
83 { .type = NLA_REJECT },
84 { .type = NLA_REJECT },
85 };
86
87 static int genl_ctrl_event(int event, const struct genl_family *family,
88 const struct genl_multicast_group *grp,
89 int grp_id);
90
91 static void
genl_op_fill_in_reject_policy(const struct genl_family * family,struct genl_ops * op)92 genl_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
genl_family_find_byid(unsigned int id)104 static const struct genl_family *genl_family_find_byid(unsigned int id)
105 {
106 return idr_find(&genl_fam_idr, id);
107 }
108
genl_family_find_byname(char * name)109 static const struct genl_family *genl_family_find_byname(char *name)
110 {
111 const struct genl_family *family;
112 unsigned int id;
113
114 idr_for_each_entry(&genl_fam_idr, family, id)
115 if (strcmp(family->name, name) == 0)
116 return family;
117
118 return NULL;
119 }
120
genl_get_cmd_cnt(const struct genl_family * family)121 static int genl_get_cmd_cnt(const struct genl_family *family)
122 {
123 return family->n_ops + family->n_small_ops;
124 }
125
genl_op_from_full(const struct genl_family * family,unsigned int i,struct genl_ops * op)126 static void genl_op_from_full(const struct genl_family *family,
127 unsigned int i, struct genl_ops *op)
128 {
129 *op = family->ops[i];
130
131 if (!op->maxattr)
132 op->maxattr = family->maxattr;
133 if (!op->policy)
134 op->policy = family->policy;
135
136 genl_op_fill_in_reject_policy(family, op);
137 }
138
genl_get_cmd_full(u32 cmd,const struct genl_family * family,struct genl_ops * op)139 static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
140 struct genl_ops *op)
141 {
142 int i;
143
144 for (i = 0; i < family->n_ops; i++)
145 if (family->ops[i].cmd == cmd) {
146 genl_op_from_full(family, i, op);
147 return 0;
148 }
149
150 return -ENOENT;
151 }
152
genl_op_from_small(const struct genl_family * family,unsigned int i,struct genl_ops * op)153 static void genl_op_from_small(const struct genl_family *family,
154 unsigned int i, struct genl_ops *op)
155 {
156 memset(op, 0, sizeof(*op));
157 op->doit = family->small_ops[i].doit;
158 op->dumpit = family->small_ops[i].dumpit;
159 op->cmd = family->small_ops[i].cmd;
160 op->internal_flags = family->small_ops[i].internal_flags;
161 op->flags = family->small_ops[i].flags;
162 op->validate = family->small_ops[i].validate;
163
164 op->maxattr = family->maxattr;
165 op->policy = family->policy;
166
167 genl_op_fill_in_reject_policy(family, op);
168 }
169
genl_get_cmd_small(u32 cmd,const struct genl_family * family,struct genl_ops * op)170 static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
171 struct genl_ops *op)
172 {
173 int i;
174
175 for (i = 0; i < family->n_small_ops; i++)
176 if (family->small_ops[i].cmd == cmd) {
177 genl_op_from_small(family, i, op);
178 return 0;
179 }
180
181 return -ENOENT;
182 }
183
genl_get_cmd(u32 cmd,const struct genl_family * family,struct genl_ops * op)184 static int genl_get_cmd(u32 cmd, const struct genl_family *family,
185 struct genl_ops *op)
186 {
187 if (!genl_get_cmd_full(cmd, family, op))
188 return 0;
189 return genl_get_cmd_small(cmd, family, op);
190 }
191
genl_get_cmd_by_index(unsigned int i,const struct genl_family * family,struct genl_ops * op)192 static void genl_get_cmd_by_index(unsigned int i,
193 const struct genl_family *family,
194 struct genl_ops *op)
195 {
196 if (i < family->n_ops)
197 genl_op_from_full(family, i, op);
198 else if (i < family->n_ops + family->n_small_ops)
199 genl_op_from_small(family, i - family->n_ops, op);
200 else
201 WARN_ON_ONCE(1);
202 }
203
genl_allocate_reserve_groups(int n_groups,int * first_id)204 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
205 {
206 unsigned long *new_groups;
207 int start = 0;
208 int i;
209 int id;
210 bool fits;
211
212 do {
213 if (start == 0)
214 id = find_first_zero_bit(mc_groups,
215 mc_groups_longs *
216 BITS_PER_LONG);
217 else
218 id = find_next_zero_bit(mc_groups,
219 mc_groups_longs * BITS_PER_LONG,
220 start);
221
222 fits = true;
223 for (i = id;
224 i < min_t(int, id + n_groups,
225 mc_groups_longs * BITS_PER_LONG);
226 i++) {
227 if (test_bit(i, mc_groups)) {
228 start = i;
229 fits = false;
230 break;
231 }
232 }
233
234 if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
235 unsigned long new_longs = mc_groups_longs +
236 BITS_TO_LONGS(n_groups);
237 size_t nlen = new_longs * sizeof(unsigned long);
238
239 if (mc_groups == &mc_group_start) {
240 new_groups = kzalloc(nlen, GFP_KERNEL);
241 if (!new_groups)
242 return -ENOMEM;
243 mc_groups = new_groups;
244 *mc_groups = mc_group_start;
245 } else {
246 new_groups = krealloc(mc_groups, nlen,
247 GFP_KERNEL);
248 if (!new_groups)
249 return -ENOMEM;
250 mc_groups = new_groups;
251 for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
252 mc_groups[mc_groups_longs + i] = 0;
253 }
254 mc_groups_longs = new_longs;
255 }
256 } while (!fits);
257
258 for (i = id; i < id + n_groups; i++)
259 set_bit(i, mc_groups);
260 *first_id = id;
261 return 0;
262 }
263
264 static struct genl_family genl_ctrl;
265
genl_validate_assign_mc_groups(struct genl_family * family)266 static int genl_validate_assign_mc_groups(struct genl_family *family)
267 {
268 int first_id;
269 int n_groups = family->n_mcgrps;
270 int err = 0, i;
271 bool groups_allocated = false;
272
273 if (!n_groups)
274 return 0;
275
276 for (i = 0; i < n_groups; i++) {
277 const struct genl_multicast_group *grp = &family->mcgrps[i];
278
279 if (WARN_ON(grp->name[0] == '\0'))
280 return -EINVAL;
281 if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
282 return -EINVAL;
283 }
284
285 /* special-case our own group and hacks */
286 if (family == &genl_ctrl) {
287 first_id = GENL_ID_CTRL;
288 BUG_ON(n_groups != 1);
289 } else if (strcmp(family->name, "NET_DM") == 0) {
290 first_id = 1;
291 BUG_ON(n_groups != 1);
292 } else if (family->id == GENL_ID_VFS_DQUOT) {
293 first_id = GENL_ID_VFS_DQUOT;
294 BUG_ON(n_groups != 1);
295 } else if (family->id == GENL_ID_PMCRAID) {
296 first_id = GENL_ID_PMCRAID;
297 BUG_ON(n_groups != 1);
298 } else {
299 groups_allocated = true;
300 err = genl_allocate_reserve_groups(n_groups, &first_id);
301 if (err)
302 return err;
303 }
304
305 family->mcgrp_offset = first_id;
306
307 /* if still initializing, can't and don't need to realloc bitmaps */
308 if (!init_net.genl_sock)
309 return 0;
310
311 if (family->netnsok) {
312 struct net *net;
313
314 netlink_table_grab();
315 rcu_read_lock();
316 for_each_net_rcu(net) {
317 err = __netlink_change_ngroups(net->genl_sock,
318 mc_groups_longs * BITS_PER_LONG);
319 if (err) {
320 /*
321 * No need to roll back, can only fail if
322 * memory allocation fails and then the
323 * number of _possible_ groups has been
324 * increased on some sockets which is ok.
325 */
326 break;
327 }
328 }
329 rcu_read_unlock();
330 netlink_table_ungrab();
331 } else {
332 err = netlink_change_ngroups(init_net.genl_sock,
333 mc_groups_longs * BITS_PER_LONG);
334 }
335
336 if (groups_allocated && err) {
337 for (i = 0; i < family->n_mcgrps; i++)
338 clear_bit(family->mcgrp_offset + i, mc_groups);
339 }
340
341 return err;
342 }
343
genl_unregister_mc_groups(const struct genl_family * family)344 static void genl_unregister_mc_groups(const struct genl_family *family)
345 {
346 struct net *net;
347 int i;
348
349 netlink_table_grab();
350 rcu_read_lock();
351 for_each_net_rcu(net) {
352 for (i = 0; i < family->n_mcgrps; i++)
353 __netlink_clear_multicast_users(
354 net->genl_sock, family->mcgrp_offset + i);
355 }
356 rcu_read_unlock();
357 netlink_table_ungrab();
358
359 for (i = 0; i < family->n_mcgrps; i++) {
360 int grp_id = family->mcgrp_offset + i;
361
362 if (grp_id != 1)
363 clear_bit(grp_id, mc_groups);
364 genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
365 &family->mcgrps[i], grp_id);
366 }
367 }
368
genl_validate_ops(const struct genl_family * family)369 static int genl_validate_ops(const struct genl_family *family)
370 {
371 int i, j;
372
373 if (WARN_ON(family->n_ops && !family->ops) ||
374 WARN_ON(family->n_small_ops && !family->small_ops))
375 return -EINVAL;
376
377 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
378 struct genl_ops op;
379
380 genl_get_cmd_by_index(i, family, &op);
381 if (op.dumpit == NULL && op.doit == NULL)
382 return -EINVAL;
383 if (WARN_ON(op.cmd >= family->resv_start_op && op.validate))
384 return -EINVAL;
385 for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
386 struct genl_ops op2;
387
388 genl_get_cmd_by_index(j, family, &op2);
389 if (op.cmd == op2.cmd)
390 return -EINVAL;
391 }
392 }
393
394 return 0;
395 }
396
397 /**
398 * genl_register_family - register a generic netlink family
399 * @family: generic netlink family
400 *
401 * Registers the specified family after validating it first. Only one
402 * family may be registered with the same family name or identifier.
403 *
404 * The family's ops, multicast groups and module pointer must already
405 * be assigned.
406 *
407 * Return 0 on success or a negative error code.
408 */
genl_register_family(struct genl_family * family)409 int genl_register_family(struct genl_family *family)
410 {
411 int err, i;
412 int start = GENL_START_ALLOC, end = GENL_MAX_ID;
413
414 err = genl_validate_ops(family);
415 if (err)
416 return err;
417
418 genl_lock_all();
419
420 if (genl_family_find_byname(family->name)) {
421 err = -EEXIST;
422 goto errout_locked;
423 }
424
425 /*
426 * Sadly, a few cases need to be special-cased
427 * due to them having previously abused the API
428 * and having used their family ID also as their
429 * multicast group ID, so we use reserved IDs
430 * for both to be sure we can do that mapping.
431 */
432 if (family == &genl_ctrl) {
433 /* and this needs to be special for initial family lookups */
434 start = end = GENL_ID_CTRL;
435 } else if (strcmp(family->name, "pmcraid") == 0) {
436 start = end = GENL_ID_PMCRAID;
437 } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
438 start = end = GENL_ID_VFS_DQUOT;
439 }
440
441 family->id = idr_alloc_cyclic(&genl_fam_idr, family,
442 start, end + 1, GFP_KERNEL);
443 if (family->id < 0) {
444 err = family->id;
445 goto errout_locked;
446 }
447
448 err = genl_validate_assign_mc_groups(family);
449 if (err)
450 goto errout_remove;
451
452 genl_unlock_all();
453
454 /* send all events */
455 genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
456 for (i = 0; i < family->n_mcgrps; i++)
457 genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
458 &family->mcgrps[i], family->mcgrp_offset + i);
459
460 return 0;
461
462 errout_remove:
463 idr_remove(&genl_fam_idr, family->id);
464 errout_locked:
465 genl_unlock_all();
466 return err;
467 }
468 EXPORT_SYMBOL(genl_register_family);
469
470 /**
471 * genl_unregister_family - unregister generic netlink family
472 * @family: generic netlink family
473 *
474 * Unregisters the specified family.
475 *
476 * Returns 0 on success or a negative error code.
477 */
genl_unregister_family(const struct genl_family * family)478 int genl_unregister_family(const struct genl_family *family)
479 {
480 genl_lock_all();
481
482 if (!genl_family_find_byid(family->id)) {
483 genl_unlock_all();
484 return -ENOENT;
485 }
486
487 genl_unregister_mc_groups(family);
488
489 idr_remove(&genl_fam_idr, family->id);
490
491 up_write(&cb_lock);
492 wait_event(genl_sk_destructing_waitq,
493 atomic_read(&genl_sk_destructing_cnt) == 0);
494 genl_unlock();
495
496 genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
497
498 return 0;
499 }
500 EXPORT_SYMBOL(genl_unregister_family);
501
502 /**
503 * genlmsg_put - Add generic netlink header to netlink message
504 * @skb: socket buffer holding the message
505 * @portid: netlink portid the message is addressed to
506 * @seq: sequence number (usually the one of the sender)
507 * @family: generic netlink family
508 * @flags: netlink message flags
509 * @cmd: generic netlink command
510 *
511 * Returns pointer to user specific header
512 */
genlmsg_put(struct sk_buff * skb,u32 portid,u32 seq,const struct genl_family * family,int flags,u8 cmd)513 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
514 const struct genl_family *family, int flags, u8 cmd)
515 {
516 struct nlmsghdr *nlh;
517 struct genlmsghdr *hdr;
518
519 nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
520 family->hdrsize, flags);
521 if (nlh == NULL)
522 return NULL;
523
524 hdr = nlmsg_data(nlh);
525 hdr->cmd = cmd;
526 hdr->version = family->version;
527 hdr->reserved = 0;
528
529 return (char *) hdr + GENL_HDRLEN;
530 }
531 EXPORT_SYMBOL(genlmsg_put);
532
genl_dumpit_info_alloc(void)533 static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
534 {
535 return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
536 }
537
genl_dumpit_info_free(const struct genl_dumpit_info * info)538 static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
539 {
540 kfree(info);
541 }
542
543 static struct nlattr **
genl_family_rcv_msg_attrs_parse(const struct genl_family * family,struct nlmsghdr * nlh,struct netlink_ext_ack * extack,const struct genl_ops * ops,int hdrlen,enum genl_validate_flags no_strict_flag)544 genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
545 struct nlmsghdr *nlh,
546 struct netlink_ext_ack *extack,
547 const struct genl_ops *ops,
548 int hdrlen,
549 enum genl_validate_flags no_strict_flag)
550 {
551 enum netlink_validation validate = ops->validate & no_strict_flag ?
552 NL_VALIDATE_LIBERAL :
553 NL_VALIDATE_STRICT;
554 struct nlattr **attrbuf;
555 int err;
556
557 if (!ops->maxattr)
558 return NULL;
559
560 attrbuf = kmalloc_array(ops->maxattr + 1,
561 sizeof(struct nlattr *), GFP_KERNEL);
562 if (!attrbuf)
563 return ERR_PTR(-ENOMEM);
564
565 err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
566 validate, extack);
567 if (err) {
568 kfree(attrbuf);
569 return ERR_PTR(err);
570 }
571 return attrbuf;
572 }
573
genl_family_rcv_msg_attrs_free(struct nlattr ** attrbuf)574 static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
575 {
576 kfree(attrbuf);
577 }
578
579 struct genl_start_context {
580 const struct genl_family *family;
581 struct nlmsghdr *nlh;
582 struct netlink_ext_ack *extack;
583 const struct genl_ops *ops;
584 int hdrlen;
585 };
586
genl_start(struct netlink_callback * cb)587 static int genl_start(struct netlink_callback *cb)
588 {
589 struct genl_start_context *ctx = cb->data;
590 const struct genl_ops *ops = ctx->ops;
591 struct genl_dumpit_info *info;
592 struct nlattr **attrs = NULL;
593 int rc = 0;
594
595 if (ops->validate & GENL_DONT_VALIDATE_DUMP)
596 goto no_attrs;
597
598 if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
599 return -EINVAL;
600
601 attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
602 ops, ctx->hdrlen,
603 GENL_DONT_VALIDATE_DUMP_STRICT);
604 if (IS_ERR(attrs))
605 return PTR_ERR(attrs);
606
607 no_attrs:
608 info = genl_dumpit_info_alloc();
609 if (!info) {
610 genl_family_rcv_msg_attrs_free(attrs);
611 return -ENOMEM;
612 }
613 info->family = ctx->family;
614 info->op = *ops;
615 info->attrs = attrs;
616
617 cb->data = info;
618 if (ops->start) {
619 if (!ctx->family->parallel_ops)
620 genl_lock();
621 rc = ops->start(cb);
622 if (!ctx->family->parallel_ops)
623 genl_unlock();
624 }
625
626 if (rc) {
627 genl_family_rcv_msg_attrs_free(info->attrs);
628 genl_dumpit_info_free(info);
629 cb->data = NULL;
630 }
631 return rc;
632 }
633
genl_lock_dumpit(struct sk_buff * skb,struct netlink_callback * cb)634 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
635 {
636 const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
637 int rc;
638
639 genl_lock();
640 rc = ops->dumpit(skb, cb);
641 genl_unlock();
642 return rc;
643 }
644
genl_lock_done(struct netlink_callback * cb)645 static int genl_lock_done(struct netlink_callback *cb)
646 {
647 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
648 const struct genl_ops *ops = &info->op;
649 int rc = 0;
650
651 if (ops->done) {
652 genl_lock();
653 rc = ops->done(cb);
654 genl_unlock();
655 }
656 genl_family_rcv_msg_attrs_free(info->attrs);
657 genl_dumpit_info_free(info);
658 return rc;
659 }
660
genl_parallel_done(struct netlink_callback * cb)661 static int genl_parallel_done(struct netlink_callback *cb)
662 {
663 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
664 const struct genl_ops *ops = &info->op;
665 int rc = 0;
666
667 if (ops->done)
668 rc = ops->done(cb);
669 genl_family_rcv_msg_attrs_free(info->attrs);
670 genl_dumpit_info_free(info);
671 return rc;
672 }
673
genl_family_rcv_msg_dumpit(const struct genl_family * family,struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack,const struct genl_ops * ops,int hdrlen,struct net * net)674 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
675 struct sk_buff *skb,
676 struct nlmsghdr *nlh,
677 struct netlink_ext_ack *extack,
678 const struct genl_ops *ops,
679 int hdrlen, struct net *net)
680 {
681 struct genl_start_context ctx;
682 int err;
683
684 if (!ops->dumpit)
685 return -EOPNOTSUPP;
686
687 ctx.family = family;
688 ctx.nlh = nlh;
689 ctx.extack = extack;
690 ctx.ops = ops;
691 ctx.hdrlen = hdrlen;
692
693 if (!family->parallel_ops) {
694 struct netlink_dump_control c = {
695 .module = family->module,
696 .data = &ctx,
697 .start = genl_start,
698 .dump = genl_lock_dumpit,
699 .done = genl_lock_done,
700 };
701
702 genl_unlock();
703 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
704 genl_lock();
705 } else {
706 struct netlink_dump_control c = {
707 .module = family->module,
708 .data = &ctx,
709 .start = genl_start,
710 .dump = ops->dumpit,
711 .done = genl_parallel_done,
712 };
713
714 err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
715 }
716
717 return err;
718 }
719
genl_family_rcv_msg_doit(const struct genl_family * family,struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack,const struct genl_ops * ops,int hdrlen,struct net * net)720 static int genl_family_rcv_msg_doit(const struct genl_family *family,
721 struct sk_buff *skb,
722 struct nlmsghdr *nlh,
723 struct netlink_ext_ack *extack,
724 const struct genl_ops *ops,
725 int hdrlen, struct net *net)
726 {
727 struct nlattr **attrbuf;
728 struct genl_info info;
729 int err;
730
731 if (!ops->doit)
732 return -EOPNOTSUPP;
733
734 attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
735 ops, hdrlen,
736 GENL_DONT_VALIDATE_STRICT);
737 if (IS_ERR(attrbuf))
738 return PTR_ERR(attrbuf);
739
740 info.snd_seq = nlh->nlmsg_seq;
741 info.snd_portid = NETLINK_CB(skb).portid;
742 info.nlhdr = nlh;
743 info.genlhdr = nlmsg_data(nlh);
744 info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
745 info.attrs = attrbuf;
746 info.extack = extack;
747 genl_info_net_set(&info, net);
748 memset(&info.user_ptr, 0, sizeof(info.user_ptr));
749
750 if (family->pre_doit) {
751 err = family->pre_doit(ops, skb, &info);
752 if (err)
753 goto out;
754 }
755
756 err = ops->doit(skb, &info);
757
758 if (family->post_doit)
759 family->post_doit(ops, skb, &info);
760
761 out:
762 genl_family_rcv_msg_attrs_free(attrbuf);
763
764 return err;
765 }
766
genl_header_check(const struct genl_family * family,struct nlmsghdr * nlh,struct genlmsghdr * hdr,struct netlink_ext_ack * extack)767 static int genl_header_check(const struct genl_family *family,
768 struct nlmsghdr *nlh, struct genlmsghdr *hdr,
769 struct netlink_ext_ack *extack)
770 {
771 u16 flags;
772
773 /* Only for commands added after we started validating */
774 if (hdr->cmd < family->resv_start_op)
775 return 0;
776
777 if (hdr->reserved) {
778 NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0");
779 return -EINVAL;
780 }
781
782 /* Old netlink flags have pretty loose semantics, allow only the flags
783 * consumed by the core where we can enforce the meaning.
784 */
785 flags = nlh->nlmsg_flags;
786 if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */
787 flags &= ~NLM_F_DUMP;
788 if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) {
789 NL_SET_ERR_MSG(extack,
790 "ambiguous or reserved bits set in nlmsg_flags");
791 return -EINVAL;
792 }
793
794 return 0;
795 }
796
genl_family_rcv_msg(const struct genl_family * family,struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)797 static int genl_family_rcv_msg(const struct genl_family *family,
798 struct sk_buff *skb,
799 struct nlmsghdr *nlh,
800 struct netlink_ext_ack *extack)
801 {
802 struct net *net = sock_net(skb->sk);
803 struct genlmsghdr *hdr = nlmsg_data(nlh);
804 struct genl_ops op;
805 int hdrlen;
806
807 /* this family doesn't exist in this netns */
808 if (!family->netnsok && !net_eq(net, &init_net))
809 return -ENOENT;
810
811 hdrlen = GENL_HDRLEN + family->hdrsize;
812 if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
813 return -EINVAL;
814
815 if (genl_header_check(family, nlh, hdr, extack))
816 return -EINVAL;
817
818 if (genl_get_cmd(hdr->cmd, family, &op))
819 return -EOPNOTSUPP;
820
821 if ((op.flags & GENL_ADMIN_PERM) &&
822 !netlink_capable(skb, CAP_NET_ADMIN))
823 return -EPERM;
824
825 if ((op.flags & GENL_UNS_ADMIN_PERM) &&
826 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
827 return -EPERM;
828
829 if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
830 return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
831 &op, hdrlen, net);
832 else
833 return genl_family_rcv_msg_doit(family, skb, nlh, extack,
834 &op, hdrlen, net);
835 }
836
genl_rcv_msg(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)837 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
838 struct netlink_ext_ack *extack)
839 {
840 const struct genl_family *family;
841 int err;
842
843 family = genl_family_find_byid(nlh->nlmsg_type);
844 if (family == NULL)
845 return -ENOENT;
846
847 if (!family->parallel_ops)
848 genl_lock();
849
850 err = genl_family_rcv_msg(family, skb, nlh, extack);
851
852 if (!family->parallel_ops)
853 genl_unlock();
854
855 return err;
856 }
857
genl_rcv(struct sk_buff * skb)858 static void genl_rcv(struct sk_buff *skb)
859 {
860 down_read(&cb_lock);
861 netlink_rcv_skb(skb, &genl_rcv_msg);
862 up_read(&cb_lock);
863 }
864
865 /**************************************************************************
866 * Controller
867 **************************************************************************/
868
869 static struct genl_family genl_ctrl;
870
ctrl_fill_info(const struct genl_family * family,u32 portid,u32 seq,u32 flags,struct sk_buff * skb,u8 cmd)871 static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
872 u32 flags, struct sk_buff *skb, u8 cmd)
873 {
874 void *hdr;
875
876 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
877 if (hdr == NULL)
878 return -1;
879
880 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
881 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
882 nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
883 nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
884 nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
885 goto nla_put_failure;
886
887 if (genl_get_cmd_cnt(family)) {
888 struct nlattr *nla_ops;
889 int i;
890
891 nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
892 if (nla_ops == NULL)
893 goto nla_put_failure;
894
895 for (i = 0; i < genl_get_cmd_cnt(family); i++) {
896 struct nlattr *nest;
897 struct genl_ops op;
898 u32 op_flags;
899
900 genl_get_cmd_by_index(i, family, &op);
901 op_flags = op.flags;
902 if (op.dumpit)
903 op_flags |= GENL_CMD_CAP_DUMP;
904 if (op.doit)
905 op_flags |= GENL_CMD_CAP_DO;
906 if (op.policy)
907 op_flags |= GENL_CMD_CAP_HASPOL;
908
909 nest = nla_nest_start_noflag(skb, i + 1);
910 if (nest == NULL)
911 goto nla_put_failure;
912
913 if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
914 nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
915 goto nla_put_failure;
916
917 nla_nest_end(skb, nest);
918 }
919
920 nla_nest_end(skb, nla_ops);
921 }
922
923 if (family->n_mcgrps) {
924 struct nlattr *nla_grps;
925 int i;
926
927 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
928 if (nla_grps == NULL)
929 goto nla_put_failure;
930
931 for (i = 0; i < family->n_mcgrps; i++) {
932 struct nlattr *nest;
933 const struct genl_multicast_group *grp;
934
935 grp = &family->mcgrps[i];
936
937 nest = nla_nest_start_noflag(skb, i + 1);
938 if (nest == NULL)
939 goto nla_put_failure;
940
941 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
942 family->mcgrp_offset + i) ||
943 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
944 grp->name))
945 goto nla_put_failure;
946
947 nla_nest_end(skb, nest);
948 }
949 nla_nest_end(skb, nla_grps);
950 }
951
952 genlmsg_end(skb, hdr);
953 return 0;
954
955 nla_put_failure:
956 genlmsg_cancel(skb, hdr);
957 return -EMSGSIZE;
958 }
959
ctrl_fill_mcgrp_info(const struct genl_family * family,const struct genl_multicast_group * grp,int grp_id,u32 portid,u32 seq,u32 flags,struct sk_buff * skb,u8 cmd)960 static int ctrl_fill_mcgrp_info(const struct genl_family *family,
961 const struct genl_multicast_group *grp,
962 int grp_id, u32 portid, u32 seq, u32 flags,
963 struct sk_buff *skb, u8 cmd)
964 {
965 void *hdr;
966 struct nlattr *nla_grps;
967 struct nlattr *nest;
968
969 hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
970 if (hdr == NULL)
971 return -1;
972
973 if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
974 nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
975 goto nla_put_failure;
976
977 nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
978 if (nla_grps == NULL)
979 goto nla_put_failure;
980
981 nest = nla_nest_start_noflag(skb, 1);
982 if (nest == NULL)
983 goto nla_put_failure;
984
985 if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
986 nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
987 grp->name))
988 goto nla_put_failure;
989
990 nla_nest_end(skb, nest);
991 nla_nest_end(skb, nla_grps);
992
993 genlmsg_end(skb, hdr);
994 return 0;
995
996 nla_put_failure:
997 genlmsg_cancel(skb, hdr);
998 return -EMSGSIZE;
999 }
1000
ctrl_dumpfamily(struct sk_buff * skb,struct netlink_callback * cb)1001 static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
1002 {
1003 int n = 0;
1004 struct genl_family *rt;
1005 struct net *net = sock_net(skb->sk);
1006 int fams_to_skip = cb->args[0];
1007 unsigned int id;
1008
1009 idr_for_each_entry(&genl_fam_idr, rt, id) {
1010 if (!rt->netnsok && !net_eq(net, &init_net))
1011 continue;
1012
1013 if (n++ < fams_to_skip)
1014 continue;
1015
1016 if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
1017 cb->nlh->nlmsg_seq, NLM_F_MULTI,
1018 skb, CTRL_CMD_NEWFAMILY) < 0) {
1019 n--;
1020 break;
1021 }
1022 }
1023
1024 cb->args[0] = n;
1025 return skb->len;
1026 }
1027
ctrl_build_family_msg(const struct genl_family * family,u32 portid,int seq,u8 cmd)1028 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
1029 u32 portid, int seq, u8 cmd)
1030 {
1031 struct sk_buff *skb;
1032 int err;
1033
1034 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1035 if (skb == NULL)
1036 return ERR_PTR(-ENOBUFS);
1037
1038 err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
1039 if (err < 0) {
1040 nlmsg_free(skb);
1041 return ERR_PTR(err);
1042 }
1043
1044 return skb;
1045 }
1046
1047 static struct sk_buff *
ctrl_build_mcgrp_msg(const struct genl_family * family,const struct genl_multicast_group * grp,int grp_id,u32 portid,int seq,u8 cmd)1048 ctrl_build_mcgrp_msg(const struct genl_family *family,
1049 const struct genl_multicast_group *grp,
1050 int grp_id, u32 portid, int seq, u8 cmd)
1051 {
1052 struct sk_buff *skb;
1053 int err;
1054
1055 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1056 if (skb == NULL)
1057 return ERR_PTR(-ENOBUFS);
1058
1059 err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
1060 seq, 0, skb, cmd);
1061 if (err < 0) {
1062 nlmsg_free(skb);
1063 return ERR_PTR(err);
1064 }
1065
1066 return skb;
1067 }
1068
1069 static const struct nla_policy ctrl_policy_family[] = {
1070 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1071 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1072 .len = GENL_NAMSIZ - 1 },
1073 };
1074
ctrl_getfamily(struct sk_buff * skb,struct genl_info * info)1075 static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
1076 {
1077 struct sk_buff *msg;
1078 const struct genl_family *res = NULL;
1079 int err = -EINVAL;
1080
1081 if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
1082 u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
1083 res = genl_family_find_byid(id);
1084 err = -ENOENT;
1085 }
1086
1087 if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
1088 char *name;
1089
1090 name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
1091 res = genl_family_find_byname(name);
1092 #ifdef CONFIG_MODULES
1093 if (res == NULL) {
1094 genl_unlock();
1095 up_read(&cb_lock);
1096 request_module("net-pf-%d-proto-%d-family-%s",
1097 PF_NETLINK, NETLINK_GENERIC, name);
1098 down_read(&cb_lock);
1099 genl_lock();
1100 res = genl_family_find_byname(name);
1101 }
1102 #endif
1103 err = -ENOENT;
1104 }
1105
1106 if (res == NULL)
1107 return err;
1108
1109 if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
1110 /* family doesn't exist here */
1111 return -ENOENT;
1112 }
1113
1114 msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
1115 CTRL_CMD_NEWFAMILY);
1116 if (IS_ERR(msg))
1117 return PTR_ERR(msg);
1118
1119 return genlmsg_reply(msg, info);
1120 }
1121
genl_ctrl_event(int event,const struct genl_family * family,const struct genl_multicast_group * grp,int grp_id)1122 static int genl_ctrl_event(int event, const struct genl_family *family,
1123 const struct genl_multicast_group *grp,
1124 int grp_id)
1125 {
1126 struct sk_buff *msg;
1127
1128 /* genl is still initialising */
1129 if (!init_net.genl_sock)
1130 return 0;
1131
1132 switch (event) {
1133 case CTRL_CMD_NEWFAMILY:
1134 case CTRL_CMD_DELFAMILY:
1135 WARN_ON(grp);
1136 msg = ctrl_build_family_msg(family, 0, 0, event);
1137 break;
1138 case CTRL_CMD_NEWMCAST_GRP:
1139 case CTRL_CMD_DELMCAST_GRP:
1140 BUG_ON(!grp);
1141 msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
1142 break;
1143 default:
1144 return -EINVAL;
1145 }
1146
1147 if (IS_ERR(msg))
1148 return PTR_ERR(msg);
1149
1150 if (!family->netnsok) {
1151 genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
1152 0, GFP_KERNEL);
1153 } else {
1154 rcu_read_lock();
1155 genlmsg_multicast_allns(&genl_ctrl, msg, 0,
1156 0, GFP_ATOMIC);
1157 rcu_read_unlock();
1158 }
1159
1160 return 0;
1161 }
1162
1163 struct ctrl_dump_policy_ctx {
1164 struct netlink_policy_dump_state *state;
1165 const struct genl_family *rt;
1166 unsigned int opidx;
1167 u32 op;
1168 u16 fam_id;
1169 u8 policies:1,
1170 single_op:1;
1171 };
1172
1173 static const struct nla_policy ctrl_policy_policy[] = {
1174 [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
1175 [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
1176 .len = GENL_NAMSIZ - 1 },
1177 [CTRL_ATTR_OP] = { .type = NLA_U32 },
1178 };
1179
ctrl_dumppolicy_start(struct netlink_callback * cb)1180 static int ctrl_dumppolicy_start(struct netlink_callback *cb)
1181 {
1182 const struct genl_dumpit_info *info = genl_dumpit_info(cb);
1183 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1184 struct nlattr **tb = info->attrs;
1185 const struct genl_family *rt;
1186 struct genl_ops op;
1187 int err, i;
1188
1189 BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
1190
1191 if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
1192 return -EINVAL;
1193
1194 if (tb[CTRL_ATTR_FAMILY_ID]) {
1195 ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
1196 } else {
1197 rt = genl_family_find_byname(
1198 nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
1199 if (!rt)
1200 return -ENOENT;
1201 ctx->fam_id = rt->id;
1202 }
1203
1204 rt = genl_family_find_byid(ctx->fam_id);
1205 if (!rt)
1206 return -ENOENT;
1207
1208 ctx->rt = rt;
1209
1210 if (tb[CTRL_ATTR_OP]) {
1211 ctx->single_op = true;
1212 ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
1213
1214 err = genl_get_cmd(ctx->op, rt, &op);
1215 if (err) {
1216 NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
1217 return err;
1218 }
1219
1220 if (!op.policy)
1221 return -ENODATA;
1222
1223 return netlink_policy_dump_add_policy(&ctx->state, op.policy,
1224 op.maxattr);
1225 }
1226
1227 for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
1228 genl_get_cmd_by_index(i, rt, &op);
1229
1230 if (op.policy) {
1231 err = netlink_policy_dump_add_policy(&ctx->state,
1232 op.policy,
1233 op.maxattr);
1234 if (err)
1235 goto err_free_state;
1236 }
1237 }
1238
1239 if (!ctx->state)
1240 return -ENODATA;
1241 return 0;
1242
1243 err_free_state:
1244 netlink_policy_dump_free(ctx->state);
1245 return err;
1246 }
1247
ctrl_dumppolicy_prep(struct sk_buff * skb,struct netlink_callback * cb)1248 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
1249 struct netlink_callback *cb)
1250 {
1251 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1252 void *hdr;
1253
1254 hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
1255 cb->nlh->nlmsg_seq, &genl_ctrl,
1256 NLM_F_MULTI, CTRL_CMD_GETPOLICY);
1257 if (!hdr)
1258 return NULL;
1259
1260 if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
1261 return NULL;
1262
1263 return hdr;
1264 }
1265
ctrl_dumppolicy_put_op(struct sk_buff * skb,struct netlink_callback * cb,struct genl_ops * op)1266 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
1267 struct netlink_callback *cb,
1268 struct genl_ops *op)
1269 {
1270 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1271 struct nlattr *nest_pol, *nest_op;
1272 void *hdr;
1273 int idx;
1274
1275 /* skip if we have nothing to show */
1276 if (!op->policy)
1277 return 0;
1278 if (!op->doit &&
1279 (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
1280 return 0;
1281
1282 hdr = ctrl_dumppolicy_prep(skb, cb);
1283 if (!hdr)
1284 return -ENOBUFS;
1285
1286 nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
1287 if (!nest_pol)
1288 goto err;
1289
1290 nest_op = nla_nest_start(skb, op->cmd);
1291 if (!nest_op)
1292 goto err;
1293
1294 /* for now both do/dump are always the same */
1295 idx = netlink_policy_dump_get_policy_idx(ctx->state,
1296 op->policy,
1297 op->maxattr);
1298
1299 if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
1300 goto err;
1301
1302 if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
1303 nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
1304 goto err;
1305
1306 nla_nest_end(skb, nest_op);
1307 nla_nest_end(skb, nest_pol);
1308 genlmsg_end(skb, hdr);
1309
1310 return 0;
1311 err:
1312 genlmsg_cancel(skb, hdr);
1313 return -ENOBUFS;
1314 }
1315
ctrl_dumppolicy(struct sk_buff * skb,struct netlink_callback * cb)1316 static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
1317 {
1318 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1319 void *hdr;
1320
1321 if (!ctx->policies) {
1322 while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
1323 struct genl_ops op;
1324
1325 if (ctx->single_op) {
1326 int err;
1327
1328 err = genl_get_cmd(ctx->op, ctx->rt, &op);
1329 if (WARN_ON(err))
1330 return skb->len;
1331
1332 /* break out of the loop after this one */
1333 ctx->opidx = genl_get_cmd_cnt(ctx->rt);
1334 } else {
1335 genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
1336 }
1337
1338 if (ctrl_dumppolicy_put_op(skb, cb, &op))
1339 return skb->len;
1340
1341 ctx->opidx++;
1342 }
1343
1344 /* completed with the per-op policy index list */
1345 ctx->policies = true;
1346 }
1347
1348 while (netlink_policy_dump_loop(ctx->state)) {
1349 struct nlattr *nest;
1350
1351 hdr = ctrl_dumppolicy_prep(skb, cb);
1352 if (!hdr)
1353 goto nla_put_failure;
1354
1355 nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
1356 if (!nest)
1357 goto nla_put_failure;
1358
1359 if (netlink_policy_dump_write(skb, ctx->state))
1360 goto nla_put_failure;
1361
1362 nla_nest_end(skb, nest);
1363
1364 genlmsg_end(skb, hdr);
1365 }
1366
1367 return skb->len;
1368
1369 nla_put_failure:
1370 genlmsg_cancel(skb, hdr);
1371 return skb->len;
1372 }
1373
ctrl_dumppolicy_done(struct netlink_callback * cb)1374 static int ctrl_dumppolicy_done(struct netlink_callback *cb)
1375 {
1376 struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
1377
1378 netlink_policy_dump_free(ctx->state);
1379 return 0;
1380 }
1381
1382 static const struct genl_ops genl_ctrl_ops[] = {
1383 {
1384 .cmd = CTRL_CMD_GETFAMILY,
1385 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1386 .policy = ctrl_policy_family,
1387 .maxattr = ARRAY_SIZE(ctrl_policy_family) - 1,
1388 .doit = ctrl_getfamily,
1389 .dumpit = ctrl_dumpfamily,
1390 },
1391 {
1392 .cmd = CTRL_CMD_GETPOLICY,
1393 .policy = ctrl_policy_policy,
1394 .maxattr = ARRAY_SIZE(ctrl_policy_policy) - 1,
1395 .start = ctrl_dumppolicy_start,
1396 .dumpit = ctrl_dumppolicy,
1397 .done = ctrl_dumppolicy_done,
1398 },
1399 };
1400
1401 static const struct genl_multicast_group genl_ctrl_groups[] = {
1402 { .name = "notify", },
1403 };
1404
1405 static struct genl_family genl_ctrl __ro_after_init = {
1406 .module = THIS_MODULE,
1407 .ops = genl_ctrl_ops,
1408 .n_ops = ARRAY_SIZE(genl_ctrl_ops),
1409 .resv_start_op = CTRL_CMD_GETPOLICY + 1,
1410 .mcgrps = genl_ctrl_groups,
1411 .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
1412 .id = GENL_ID_CTRL,
1413 .name = "nlctrl",
1414 .version = 0x2,
1415 .netnsok = true,
1416 };
1417
genl_bind(struct net * net,int group)1418 static int genl_bind(struct net *net, int group)
1419 {
1420 const struct genl_family *family;
1421 unsigned int id;
1422 int ret = 0;
1423
1424 down_read(&cb_lock);
1425
1426 idr_for_each_entry(&genl_fam_idr, family, id) {
1427 const struct genl_multicast_group *grp;
1428 int i;
1429
1430 if (family->n_mcgrps == 0)
1431 continue;
1432
1433 i = group - family->mcgrp_offset;
1434 if (i < 0 || i >= family->n_mcgrps)
1435 continue;
1436
1437 grp = &family->mcgrps[i];
1438 if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
1439 !ns_capable(net->user_ns, CAP_NET_ADMIN))
1440 ret = -EPERM;
1441
1442 break;
1443 }
1444
1445 up_read(&cb_lock);
1446 return ret;
1447 }
1448
genl_pernet_init(struct net * net)1449 static int __net_init genl_pernet_init(struct net *net)
1450 {
1451 struct netlink_kernel_cfg cfg = {
1452 .input = genl_rcv,
1453 .flags = NL_CFG_F_NONROOT_RECV,
1454 .bind = genl_bind,
1455 };
1456
1457 /* we'll bump the group number right afterwards */
1458 net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
1459
1460 if (!net->genl_sock && net_eq(net, &init_net))
1461 panic("GENL: Cannot initialize generic netlink\n");
1462
1463 if (!net->genl_sock)
1464 return -ENOMEM;
1465
1466 return 0;
1467 }
1468
genl_pernet_exit(struct net * net)1469 static void __net_exit genl_pernet_exit(struct net *net)
1470 {
1471 netlink_kernel_release(net->genl_sock);
1472 net->genl_sock = NULL;
1473 }
1474
1475 static struct pernet_operations genl_pernet_ops = {
1476 .init = genl_pernet_init,
1477 .exit = genl_pernet_exit,
1478 };
1479
genl_init(void)1480 static int __init genl_init(void)
1481 {
1482 int err;
1483
1484 err = genl_register_family(&genl_ctrl);
1485 if (err < 0)
1486 goto problem;
1487
1488 err = register_pernet_subsys(&genl_pernet_ops);
1489 if (err)
1490 goto problem;
1491
1492 return 0;
1493
1494 problem:
1495 panic("GENL: Cannot register controller: %d\n", err);
1496 }
1497
1498 core_initcall(genl_init);
1499
genlmsg_mcast(struct sk_buff * skb,u32 portid,unsigned long group,gfp_t flags)1500 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
1501 gfp_t flags)
1502 {
1503 struct sk_buff *tmp;
1504 struct net *net, *prev = NULL;
1505 bool delivered = false;
1506 int err;
1507
1508 for_each_net_rcu(net) {
1509 if (prev) {
1510 tmp = skb_clone(skb, flags);
1511 if (!tmp) {
1512 err = -ENOMEM;
1513 goto error;
1514 }
1515 err = nlmsg_multicast(prev->genl_sock, tmp,
1516 portid, group, flags);
1517 if (!err)
1518 delivered = true;
1519 else if (err != -ESRCH)
1520 goto error;
1521 }
1522
1523 prev = net;
1524 }
1525
1526 err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
1527 if (!err)
1528 delivered = true;
1529 else if (err != -ESRCH)
1530 return err;
1531 return delivered ? 0 : -ESRCH;
1532 error:
1533 kfree_skb(skb);
1534 return err;
1535 }
1536
genlmsg_multicast_allns(const struct genl_family * family,struct sk_buff * skb,u32 portid,unsigned int group,gfp_t flags)1537 int genlmsg_multicast_allns(const struct genl_family *family,
1538 struct sk_buff *skb, u32 portid,
1539 unsigned int group, gfp_t flags)
1540 {
1541 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1542 return -EINVAL;
1543
1544 group = family->mcgrp_offset + group;
1545 return genlmsg_mcast(skb, portid, group, flags);
1546 }
1547 EXPORT_SYMBOL(genlmsg_multicast_allns);
1548
genl_notify(const struct genl_family * family,struct sk_buff * skb,struct genl_info * info,u32 group,gfp_t flags)1549 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
1550 struct genl_info *info, u32 group, gfp_t flags)
1551 {
1552 struct net *net = genl_info_net(info);
1553 struct sock *sk = net->genl_sock;
1554
1555 if (WARN_ON_ONCE(group >= family->n_mcgrps))
1556 return;
1557
1558 group = family->mcgrp_offset + group;
1559 nlmsg_notify(sk, skb, info->snd_portid, group,
1560 nlmsg_report(info->nlhdr), flags);
1561 }
1562 EXPORT_SYMBOL(genl_notify);
1563