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Commit | Line | Data |
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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 <linux/idr.h> | |
21 | #include <net/sock.h> | |
22 | #include <net/genetlink.h> | |
23 | ||
24 | static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ | |
25 | static DECLARE_RWSEM(cb_lock); | |
26 | ||
27 | atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); | |
28 | DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); | |
29 | ||
30 | void genl_lock(void) | |
31 | { | |
32 | mutex_lock(&genl_mutex); | |
33 | } | |
34 | EXPORT_SYMBOL(genl_lock); | |
35 | ||
36 | void genl_unlock(void) | |
37 | { | |
38 | mutex_unlock(&genl_mutex); | |
39 | } | |
40 | EXPORT_SYMBOL(genl_unlock); | |
41 | ||
42 | #ifdef CONFIG_LOCKDEP | |
43 | bool lockdep_genl_is_held(void) | |
44 | { | |
45 | return lockdep_is_held(&genl_mutex); | |
46 | } | |
47 | EXPORT_SYMBOL(lockdep_genl_is_held); | |
48 | #endif | |
49 | ||
50 | static void genl_lock_all(void) | |
51 | { | |
52 | down_write(&cb_lock); | |
53 | genl_lock(); | |
54 | } | |
55 | ||
56 | static void genl_unlock_all(void) | |
57 | { | |
58 | genl_unlock(); | |
59 | up_write(&cb_lock); | |
60 | } | |
61 | ||
62 | static DEFINE_IDR(genl_fam_idr); | |
63 | ||
64 | /* | |
65 | * Bitmap of multicast groups that are currently in use. | |
66 | * | |
67 | * To avoid an allocation at boot of just one unsigned long, | |
68 | * declare it global instead. | |
69 | * Bit 0 is marked as already used since group 0 is invalid. | |
70 | * Bit 1 is marked as already used since the drop-monitor code | |
71 | * abuses the API and thinks it can statically use group 1. | |
72 | * That group will typically conflict with other groups that | |
73 | * any proper users use. | |
74 | * Bit 16 is marked as used since it's used for generic netlink | |
75 | * and the code no longer marks pre-reserved IDs as used. | |
76 | * Bit 17 is marked as already used since the VFS quota code | |
77 | * also abused this API and relied on family == group ID, we | |
78 | * cater to that by giving it a static family and group ID. | |
79 | * Bit 18 is marked as already used since the PMCRAID driver | |
80 | * did the same thing as the VFS quota code (maybe copied?) | |
81 | */ | |
82 | static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | | |
83 | BIT(GENL_ID_VFS_DQUOT) | | |
84 | BIT(GENL_ID_PMCRAID); | |
85 | static unsigned long *mc_groups = &mc_group_start; | |
86 | static unsigned long mc_groups_longs = 1; | |
87 | ||
88 | static int genl_ctrl_event(int event, const struct genl_family *family, | |
89 | const struct genl_multicast_group *grp, | |
90 | int grp_id); | |
91 | ||
92 | static const struct genl_family *genl_family_find_byid(unsigned int id) | |
93 | { | |
94 | return idr_find(&genl_fam_idr, id); | |
95 | } | |
96 | ||
97 | static const struct genl_family *genl_family_find_byname(char *name) | |
98 | { | |
99 | const struct genl_family *family; | |
100 | unsigned int id; | |
101 | ||
102 | idr_for_each_entry(&genl_fam_idr, family, id) | |
103 | if (strcmp(family->name, name) == 0) | |
104 | return family; | |
105 | ||
106 | return NULL; | |
107 | } | |
108 | ||
109 | static const struct genl_ops *genl_get_cmd(u8 cmd, | |
110 | const struct genl_family *family) | |
111 | { | |
112 | int i; | |
113 | ||
114 | for (i = 0; i < family->n_ops; i++) | |
115 | if (family->ops[i].cmd == cmd) | |
116 | return &family->ops[i]; | |
117 | ||
118 | return NULL; | |
119 | } | |
120 | ||
121 | static int genl_allocate_reserve_groups(int n_groups, int *first_id) | |
122 | { | |
123 | unsigned long *new_groups; | |
124 | int start = 0; | |
125 | int i; | |
126 | int id; | |
127 | bool fits; | |
128 | ||
129 | do { | |
130 | if (start == 0) | |
131 | id = find_first_zero_bit(mc_groups, | |
132 | mc_groups_longs * | |
133 | BITS_PER_LONG); | |
134 | else | |
135 | id = find_next_zero_bit(mc_groups, | |
136 | mc_groups_longs * BITS_PER_LONG, | |
137 | start); | |
138 | ||
139 | fits = true; | |
140 | for (i = id; | |
141 | i < min_t(int, id + n_groups, | |
142 | mc_groups_longs * BITS_PER_LONG); | |
143 | i++) { | |
144 | if (test_bit(i, mc_groups)) { | |
145 | start = i; | |
146 | fits = false; | |
147 | break; | |
148 | } | |
149 | } | |
150 | ||
151 | if (id + n_groups > mc_groups_longs * BITS_PER_LONG) { | |
152 | unsigned long new_longs = mc_groups_longs + | |
153 | BITS_TO_LONGS(n_groups); | |
154 | size_t nlen = new_longs * sizeof(unsigned long); | |
155 | ||
156 | if (mc_groups == &mc_group_start) { | |
157 | new_groups = kzalloc(nlen, GFP_KERNEL); | |
158 | if (!new_groups) | |
159 | return -ENOMEM; | |
160 | mc_groups = new_groups; | |
161 | *mc_groups = mc_group_start; | |
162 | } else { | |
163 | new_groups = krealloc(mc_groups, nlen, | |
164 | GFP_KERNEL); | |
165 | if (!new_groups) | |
166 | return -ENOMEM; | |
167 | mc_groups = new_groups; | |
168 | for (i = 0; i < BITS_TO_LONGS(n_groups); i++) | |
169 | mc_groups[mc_groups_longs + i] = 0; | |
170 | } | |
171 | mc_groups_longs = new_longs; | |
172 | } | |
173 | } while (!fits); | |
174 | ||
175 | for (i = id; i < id + n_groups; i++) | |
176 | set_bit(i, mc_groups); | |
177 | *first_id = id; | |
178 | return 0; | |
179 | } | |
180 | ||
181 | static struct genl_family genl_ctrl; | |
182 | ||
183 | static int genl_validate_assign_mc_groups(struct genl_family *family) | |
184 | { | |
185 | int first_id; | |
186 | int n_groups = family->n_mcgrps; | |
187 | int err = 0, i; | |
188 | bool groups_allocated = false; | |
189 | ||
190 | if (!n_groups) | |
191 | return 0; | |
192 | ||
193 | for (i = 0; i < n_groups; i++) { | |
194 | const struct genl_multicast_group *grp = &family->mcgrps[i]; | |
195 | ||
196 | if (WARN_ON(grp->name[0] == '\0')) | |
197 | return -EINVAL; | |
198 | if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) | |
199 | return -EINVAL; | |
200 | } | |
201 | ||
202 | /* special-case our own group and hacks */ | |
203 | if (family == &genl_ctrl) { | |
204 | first_id = GENL_ID_CTRL; | |
205 | BUG_ON(n_groups != 1); | |
206 | } else if (strcmp(family->name, "NET_DM") == 0) { | |
207 | first_id = 1; | |
208 | BUG_ON(n_groups != 1); | |
209 | } else if (family->id == GENL_ID_VFS_DQUOT) { | |
210 | first_id = GENL_ID_VFS_DQUOT; | |
211 | BUG_ON(n_groups != 1); | |
212 | } else if (family->id == GENL_ID_PMCRAID) { | |
213 | first_id = GENL_ID_PMCRAID; | |
214 | BUG_ON(n_groups != 1); | |
215 | } else { | |
216 | groups_allocated = true; | |
217 | err = genl_allocate_reserve_groups(n_groups, &first_id); | |
218 | if (err) | |
219 | return err; | |
220 | } | |
221 | ||
222 | family->mcgrp_offset = first_id; | |
223 | ||
224 | /* if still initializing, can't and don't need to to realloc bitmaps */ | |
225 | if (!init_net.genl_sock) | |
226 | return 0; | |
227 | ||
228 | if (family->netnsok) { | |
229 | struct net *net; | |
230 | ||
231 | netlink_table_grab(); | |
232 | rcu_read_lock(); | |
233 | for_each_net_rcu(net) { | |
234 | err = __netlink_change_ngroups(net->genl_sock, | |
235 | mc_groups_longs * BITS_PER_LONG); | |
236 | if (err) { | |
237 | /* | |
238 | * No need to roll back, can only fail if | |
239 | * memory allocation fails and then the | |
240 | * number of _possible_ groups has been | |
241 | * increased on some sockets which is ok. | |
242 | */ | |
243 | break; | |
244 | } | |
245 | } | |
246 | rcu_read_unlock(); | |
247 | netlink_table_ungrab(); | |
248 | } else { | |
249 | err = netlink_change_ngroups(init_net.genl_sock, | |
250 | mc_groups_longs * BITS_PER_LONG); | |
251 | } | |
252 | ||
253 | if (groups_allocated && err) { | |
254 | for (i = 0; i < family->n_mcgrps; i++) | |
255 | clear_bit(family->mcgrp_offset + i, mc_groups); | |
256 | } | |
257 | ||
258 | return err; | |
259 | } | |
260 | ||
261 | static void genl_unregister_mc_groups(const struct genl_family *family) | |
262 | { | |
263 | struct net *net; | |
264 | int i; | |
265 | ||
266 | netlink_table_grab(); | |
267 | rcu_read_lock(); | |
268 | for_each_net_rcu(net) { | |
269 | for (i = 0; i < family->n_mcgrps; i++) | |
270 | __netlink_clear_multicast_users( | |
271 | net->genl_sock, family->mcgrp_offset + i); | |
272 | } | |
273 | rcu_read_unlock(); | |
274 | netlink_table_ungrab(); | |
275 | ||
276 | for (i = 0; i < family->n_mcgrps; i++) { | |
277 | int grp_id = family->mcgrp_offset + i; | |
278 | ||
279 | if (grp_id != 1) | |
280 | clear_bit(grp_id, mc_groups); | |
281 | genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, | |
282 | &family->mcgrps[i], grp_id); | |
283 | } | |
284 | } | |
285 | ||
286 | static int genl_validate_ops(const struct genl_family *family) | |
287 | { | |
288 | const struct genl_ops *ops = family->ops; | |
289 | unsigned int n_ops = family->n_ops; | |
290 | int i, j; | |
291 | ||
292 | if (WARN_ON(n_ops && !ops)) | |
293 | return -EINVAL; | |
294 | ||
295 | if (!n_ops) | |
296 | return 0; | |
297 | ||
298 | for (i = 0; i < n_ops; i++) { | |
299 | if (ops[i].dumpit == NULL && ops[i].doit == NULL) | |
300 | return -EINVAL; | |
301 | for (j = i + 1; j < n_ops; j++) | |
302 | if (ops[i].cmd == ops[j].cmd) | |
303 | return -EINVAL; | |
304 | } | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | /** | |
310 | * genl_register_family - register a generic netlink family | |
311 | * @family: generic netlink family | |
312 | * | |
313 | * Registers the specified family after validating it first. Only one | |
314 | * family may be registered with the same family name or identifier. | |
315 | * | |
316 | * The family's ops, multicast groups and module pointer must already | |
317 | * be assigned. | |
318 | * | |
319 | * Return 0 on success or a negative error code. | |
320 | */ | |
321 | int genl_register_family(struct genl_family *family) | |
322 | { | |
323 | int err, i; | |
324 | int start = GENL_START_ALLOC, end = GENL_MAX_ID; | |
325 | ||
326 | err = genl_validate_ops(family); | |
327 | if (err) | |
328 | return err; | |
329 | ||
330 | genl_lock_all(); | |
331 | ||
332 | if (genl_family_find_byname(family->name)) { | |
333 | err = -EEXIST; | |
334 | goto errout_locked; | |
335 | } | |
336 | ||
337 | /* | |
338 | * Sadly, a few cases need to be special-cased | |
339 | * due to them having previously abused the API | |
340 | * and having used their family ID also as their | |
341 | * multicast group ID, so we use reserved IDs | |
342 | * for both to be sure we can do that mapping. | |
343 | */ | |
344 | if (family == &genl_ctrl) { | |
345 | /* and this needs to be special for initial family lookups */ | |
346 | start = end = GENL_ID_CTRL; | |
347 | } else if (strcmp(family->name, "pmcraid") == 0) { | |
348 | start = end = GENL_ID_PMCRAID; | |
349 | } else if (strcmp(family->name, "VFS_DQUOT") == 0) { | |
350 | start = end = GENL_ID_VFS_DQUOT; | |
351 | } | |
352 | ||
353 | if (family->maxattr && !family->parallel_ops) { | |
354 | family->attrbuf = kmalloc((family->maxattr+1) * | |
355 | sizeof(struct nlattr *), GFP_KERNEL); | |
356 | if (family->attrbuf == NULL) { | |
357 | err = -ENOMEM; | |
358 | goto errout_locked; | |
359 | } | |
360 | } else | |
361 | family->attrbuf = NULL; | |
362 | ||
363 | family->id = idr_alloc(&genl_fam_idr, family, | |
364 | start, end + 1, GFP_KERNEL); | |
365 | if (family->id < 0) { | |
366 | err = family->id; | |
367 | goto errout_locked; | |
368 | } | |
369 | ||
370 | err = genl_validate_assign_mc_groups(family); | |
371 | if (err) | |
372 | goto errout_remove; | |
373 | ||
374 | genl_unlock_all(); | |
375 | ||
376 | /* send all events */ | |
377 | genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); | |
378 | for (i = 0; i < family->n_mcgrps; i++) | |
379 | genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, | |
380 | &family->mcgrps[i], family->mcgrp_offset + i); | |
381 | ||
382 | return 0; | |
383 | ||
384 | errout_remove: | |
385 | idr_remove(&genl_fam_idr, family->id); | |
386 | kfree(family->attrbuf); | |
387 | errout_locked: | |
388 | genl_unlock_all(); | |
389 | return err; | |
390 | } | |
391 | EXPORT_SYMBOL(genl_register_family); | |
392 | ||
393 | /** | |
394 | * genl_unregister_family - unregister generic netlink family | |
395 | * @family: generic netlink family | |
396 | * | |
397 | * Unregisters the specified family. | |
398 | * | |
399 | * Returns 0 on success or a negative error code. | |
400 | */ | |
401 | int genl_unregister_family(const struct genl_family *family) | |
402 | { | |
403 | genl_lock_all(); | |
404 | ||
405 | if (!genl_family_find_byid(family->id)) { | |
406 | genl_unlock_all(); | |
407 | return -ENOENT; | |
408 | } | |
409 | ||
410 | genl_unregister_mc_groups(family); | |
411 | ||
412 | idr_remove(&genl_fam_idr, family->id); | |
413 | ||
414 | up_write(&cb_lock); | |
415 | wait_event(genl_sk_destructing_waitq, | |
416 | atomic_read(&genl_sk_destructing_cnt) == 0); | |
417 | genl_unlock(); | |
418 | ||
419 | kfree(family->attrbuf); | |
420 | ||
421 | genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); | |
422 | ||
423 | return 0; | |
424 | } | |
425 | EXPORT_SYMBOL(genl_unregister_family); | |
426 | ||
427 | /** | |
428 | * genlmsg_put - Add generic netlink header to netlink message | |
429 | * @skb: socket buffer holding the message | |
430 | * @portid: netlink portid the message is addressed to | |
431 | * @seq: sequence number (usually the one of the sender) | |
432 | * @family: generic netlink family | |
433 | * @flags: netlink message flags | |
434 | * @cmd: generic netlink command | |
435 | * | |
436 | * Returns pointer to user specific header | |
437 | */ | |
438 | void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, | |
439 | const struct genl_family *family, int flags, u8 cmd) | |
440 | { | |
441 | struct nlmsghdr *nlh; | |
442 | struct genlmsghdr *hdr; | |
443 | ||
444 | nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN + | |
445 | family->hdrsize, flags); | |
446 | if (nlh == NULL) | |
447 | return NULL; | |
448 | ||
449 | hdr = nlmsg_data(nlh); | |
450 | hdr->cmd = cmd; | |
451 | hdr->version = family->version; | |
452 | hdr->reserved = 0; | |
453 | ||
454 | return (char *) hdr + GENL_HDRLEN; | |
455 | } | |
456 | EXPORT_SYMBOL(genlmsg_put); | |
457 | ||
458 | static int genl_lock_start(struct netlink_callback *cb) | |
459 | { | |
460 | /* our ops are always const - netlink API doesn't propagate that */ | |
461 | const struct genl_ops *ops = cb->data; | |
462 | int rc = 0; | |
463 | ||
464 | if (ops->start) { | |
465 | genl_lock(); | |
466 | rc = ops->start(cb); | |
467 | genl_unlock(); | |
468 | } | |
469 | return rc; | |
470 | } | |
471 | ||
472 | static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) | |
473 | { | |
474 | /* our ops are always const - netlink API doesn't propagate that */ | |
475 | const struct genl_ops *ops = cb->data; | |
476 | int rc; | |
477 | ||
478 | genl_lock(); | |
479 | rc = ops->dumpit(skb, cb); | |
480 | genl_unlock(); | |
481 | return rc; | |
482 | } | |
483 | ||
484 | static int genl_lock_done(struct netlink_callback *cb) | |
485 | { | |
486 | /* our ops are always const - netlink API doesn't propagate that */ | |
487 | const struct genl_ops *ops = cb->data; | |
488 | int rc = 0; | |
489 | ||
490 | if (ops->done) { | |
491 | genl_lock(); | |
492 | rc = ops->done(cb); | |
493 | genl_unlock(); | |
494 | } | |
495 | return rc; | |
496 | } | |
497 | ||
498 | static int genl_family_rcv_msg(const struct genl_family *family, | |
499 | struct sk_buff *skb, | |
500 | struct nlmsghdr *nlh) | |
501 | { | |
502 | const struct genl_ops *ops; | |
503 | struct net *net = sock_net(skb->sk); | |
504 | struct genl_info info; | |
505 | struct genlmsghdr *hdr = nlmsg_data(nlh); | |
506 | struct nlattr **attrbuf; | |
507 | int hdrlen, err; | |
508 | ||
509 | /* this family doesn't exist in this netns */ | |
510 | if (!family->netnsok && !net_eq(net, &init_net)) | |
511 | return -ENOENT; | |
512 | ||
513 | hdrlen = GENL_HDRLEN + family->hdrsize; | |
514 | if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) | |
515 | return -EINVAL; | |
516 | ||
517 | ops = genl_get_cmd(hdr->cmd, family); | |
518 | if (ops == NULL) | |
519 | return -EOPNOTSUPP; | |
520 | ||
521 | if ((ops->flags & GENL_ADMIN_PERM) && | |
522 | !netlink_capable(skb, CAP_NET_ADMIN)) | |
523 | return -EPERM; | |
524 | ||
525 | if ((ops->flags & GENL_UNS_ADMIN_PERM) && | |
526 | !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) | |
527 | return -EPERM; | |
528 | ||
529 | if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) { | |
530 | int rc; | |
531 | ||
532 | if (ops->dumpit == NULL) | |
533 | return -EOPNOTSUPP; | |
534 | ||
535 | if (!family->parallel_ops) { | |
536 | struct netlink_dump_control c = { | |
537 | .module = family->module, | |
538 | /* we have const, but the netlink API doesn't */ | |
539 | .data = (void *)ops, | |
540 | .start = genl_lock_start, | |
541 | .dump = genl_lock_dumpit, | |
542 | .done = genl_lock_done, | |
543 | }; | |
544 | ||
545 | genl_unlock(); | |
546 | rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); | |
547 | genl_lock(); | |
548 | ||
549 | } else { | |
550 | struct netlink_dump_control c = { | |
551 | .module = family->module, | |
552 | .start = ops->start, | |
553 | .dump = ops->dumpit, | |
554 | .done = ops->done, | |
555 | }; | |
556 | ||
557 | rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c); | |
558 | } | |
559 | ||
560 | return rc; | |
561 | } | |
562 | ||
563 | if (ops->doit == NULL) | |
564 | return -EOPNOTSUPP; | |
565 | ||
566 | if (family->maxattr && family->parallel_ops) { | |
567 | attrbuf = kmalloc((family->maxattr+1) * | |
568 | sizeof(struct nlattr *), GFP_KERNEL); | |
569 | if (attrbuf == NULL) | |
570 | return -ENOMEM; | |
571 | } else | |
572 | attrbuf = family->attrbuf; | |
573 | ||
574 | if (attrbuf) { | |
575 | err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, | |
576 | ops->policy); | |
577 | if (err < 0) | |
578 | goto out; | |
579 | } | |
580 | ||
581 | info.snd_seq = nlh->nlmsg_seq; | |
582 | info.snd_portid = NETLINK_CB(skb).portid; | |
583 | info.nlhdr = nlh; | |
584 | info.genlhdr = nlmsg_data(nlh); | |
585 | info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN; | |
586 | info.attrs = attrbuf; | |
587 | genl_info_net_set(&info, net); | |
588 | memset(&info.user_ptr, 0, sizeof(info.user_ptr)); | |
589 | ||
590 | if (family->pre_doit) { | |
591 | err = family->pre_doit(ops, skb, &info); | |
592 | if (err) | |
593 | goto out; | |
594 | } | |
595 | ||
596 | err = ops->doit(skb, &info); | |
597 | ||
598 | if (family->post_doit) | |
599 | family->post_doit(ops, skb, &info); | |
600 | ||
601 | out: | |
602 | if (family->parallel_ops) | |
603 | kfree(attrbuf); | |
604 | ||
605 | return err; | |
606 | } | |
607 | ||
608 | static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) | |
609 | { | |
610 | const struct genl_family *family; | |
611 | int err; | |
612 | ||
613 | family = genl_family_find_byid(nlh->nlmsg_type); | |
614 | if (family == NULL) | |
615 | return -ENOENT; | |
616 | ||
617 | if (!family->parallel_ops) | |
618 | genl_lock(); | |
619 | ||
620 | err = genl_family_rcv_msg(family, skb, nlh); | |
621 | ||
622 | if (!family->parallel_ops) | |
623 | genl_unlock(); | |
624 | ||
625 | return err; | |
626 | } | |
627 | ||
628 | static void genl_rcv(struct sk_buff *skb) | |
629 | { | |
630 | down_read(&cb_lock); | |
631 | netlink_rcv_skb(skb, &genl_rcv_msg); | |
632 | up_read(&cb_lock); | |
633 | } | |
634 | ||
635 | /************************************************************************** | |
636 | * Controller | |
637 | **************************************************************************/ | |
638 | ||
639 | static struct genl_family genl_ctrl; | |
640 | ||
641 | static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, | |
642 | u32 flags, struct sk_buff *skb, u8 cmd) | |
643 | { | |
644 | void *hdr; | |
645 | ||
646 | hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); | |
647 | if (hdr == NULL) | |
648 | return -1; | |
649 | ||
650 | if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || | |
651 | nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) || | |
652 | nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) || | |
653 | nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) || | |
654 | nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr)) | |
655 | goto nla_put_failure; | |
656 | ||
657 | if (family->n_ops) { | |
658 | struct nlattr *nla_ops; | |
659 | int i; | |
660 | ||
661 | nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS); | |
662 | if (nla_ops == NULL) | |
663 | goto nla_put_failure; | |
664 | ||
665 | for (i = 0; i < family->n_ops; i++) { | |
666 | struct nlattr *nest; | |
667 | const struct genl_ops *ops = &family->ops[i]; | |
668 | u32 op_flags = ops->flags; | |
669 | ||
670 | if (ops->dumpit) | |
671 | op_flags |= GENL_CMD_CAP_DUMP; | |
672 | if (ops->doit) | |
673 | op_flags |= GENL_CMD_CAP_DO; | |
674 | if (ops->policy) | |
675 | op_flags |= GENL_CMD_CAP_HASPOL; | |
676 | ||
677 | nest = nla_nest_start(skb, i + 1); | |
678 | if (nest == NULL) | |
679 | goto nla_put_failure; | |
680 | ||
681 | if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) || | |
682 | nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags)) | |
683 | goto nla_put_failure; | |
684 | ||
685 | nla_nest_end(skb, nest); | |
686 | } | |
687 | ||
688 | nla_nest_end(skb, nla_ops); | |
689 | } | |
690 | ||
691 | if (family->n_mcgrps) { | |
692 | struct nlattr *nla_grps; | |
693 | int i; | |
694 | ||
695 | nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); | |
696 | if (nla_grps == NULL) | |
697 | goto nla_put_failure; | |
698 | ||
699 | for (i = 0; i < family->n_mcgrps; i++) { | |
700 | struct nlattr *nest; | |
701 | const struct genl_multicast_group *grp; | |
702 | ||
703 | grp = &family->mcgrps[i]; | |
704 | ||
705 | nest = nla_nest_start(skb, i + 1); | |
706 | if (nest == NULL) | |
707 | goto nla_put_failure; | |
708 | ||
709 | if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, | |
710 | family->mcgrp_offset + i) || | |
711 | nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, | |
712 | grp->name)) | |
713 | goto nla_put_failure; | |
714 | ||
715 | nla_nest_end(skb, nest); | |
716 | } | |
717 | nla_nest_end(skb, nla_grps); | |
718 | } | |
719 | ||
720 | genlmsg_end(skb, hdr); | |
721 | return 0; | |
722 | ||
723 | nla_put_failure: | |
724 | genlmsg_cancel(skb, hdr); | |
725 | return -EMSGSIZE; | |
726 | } | |
727 | ||
728 | static int ctrl_fill_mcgrp_info(const struct genl_family *family, | |
729 | const struct genl_multicast_group *grp, | |
730 | int grp_id, u32 portid, u32 seq, u32 flags, | |
731 | struct sk_buff *skb, u8 cmd) | |
732 | { | |
733 | void *hdr; | |
734 | struct nlattr *nla_grps; | |
735 | struct nlattr *nest; | |
736 | ||
737 | hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd); | |
738 | if (hdr == NULL) | |
739 | return -1; | |
740 | ||
741 | if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || | |
742 | nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) | |
743 | goto nla_put_failure; | |
744 | ||
745 | nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); | |
746 | if (nla_grps == NULL) | |
747 | goto nla_put_failure; | |
748 | ||
749 | nest = nla_nest_start(skb, 1); | |
750 | if (nest == NULL) | |
751 | goto nla_put_failure; | |
752 | ||
753 | if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || | |
754 | nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, | |
755 | grp->name)) | |
756 | goto nla_put_failure; | |
757 | ||
758 | nla_nest_end(skb, nest); | |
759 | nla_nest_end(skb, nla_grps); | |
760 | ||
761 | genlmsg_end(skb, hdr); | |
762 | return 0; | |
763 | ||
764 | nla_put_failure: | |
765 | genlmsg_cancel(skb, hdr); | |
766 | return -EMSGSIZE; | |
767 | } | |
768 | ||
769 | static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) | |
770 | { | |
771 | int n = 0; | |
772 | struct genl_family *rt; | |
773 | struct net *net = sock_net(skb->sk); | |
774 | int fams_to_skip = cb->args[0]; | |
775 | unsigned int id; | |
776 | ||
777 | idr_for_each_entry(&genl_fam_idr, rt, id) { | |
778 | if (!rt->netnsok && !net_eq(net, &init_net)) | |
779 | continue; | |
780 | ||
781 | if (n++ < fams_to_skip) | |
782 | continue; | |
783 | ||
784 | if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid, | |
785 | cb->nlh->nlmsg_seq, NLM_F_MULTI, | |
786 | skb, CTRL_CMD_NEWFAMILY) < 0) { | |
787 | n--; | |
788 | break; | |
789 | } | |
790 | } | |
791 | ||
792 | cb->args[0] = n; | |
793 | return skb->len; | |
794 | } | |
795 | ||
796 | static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family, | |
797 | u32 portid, int seq, u8 cmd) | |
798 | { | |
799 | struct sk_buff *skb; | |
800 | int err; | |
801 | ||
802 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
803 | if (skb == NULL) | |
804 | return ERR_PTR(-ENOBUFS); | |
805 | ||
806 | err = ctrl_fill_info(family, portid, seq, 0, skb, cmd); | |
807 | if (err < 0) { | |
808 | nlmsg_free(skb); | |
809 | return ERR_PTR(err); | |
810 | } | |
811 | ||
812 | return skb; | |
813 | } | |
814 | ||
815 | static struct sk_buff * | |
816 | ctrl_build_mcgrp_msg(const struct genl_family *family, | |
817 | const struct genl_multicast_group *grp, | |
818 | int grp_id, u32 portid, int seq, u8 cmd) | |
819 | { | |
820 | struct sk_buff *skb; | |
821 | int err; | |
822 | ||
823 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
824 | if (skb == NULL) | |
825 | return ERR_PTR(-ENOBUFS); | |
826 | ||
827 | err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, | |
828 | seq, 0, skb, cmd); | |
829 | if (err < 0) { | |
830 | nlmsg_free(skb); | |
831 | return ERR_PTR(err); | |
832 | } | |
833 | ||
834 | return skb; | |
835 | } | |
836 | ||
837 | static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = { | |
838 | [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 }, | |
839 | [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING, | |
840 | .len = GENL_NAMSIZ - 1 }, | |
841 | }; | |
842 | ||
843 | static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) | |
844 | { | |
845 | struct sk_buff *msg; | |
846 | const struct genl_family *res = NULL; | |
847 | int err = -EINVAL; | |
848 | ||
849 | if (info->attrs[CTRL_ATTR_FAMILY_ID]) { | |
850 | u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]); | |
851 | res = genl_family_find_byid(id); | |
852 | err = -ENOENT; | |
853 | } | |
854 | ||
855 | if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { | |
856 | char *name; | |
857 | ||
858 | name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]); | |
859 | res = genl_family_find_byname(name); | |
860 | #ifdef CONFIG_MODULES | |
861 | if (res == NULL) { | |
862 | genl_unlock(); | |
863 | up_read(&cb_lock); | |
864 | request_module("net-pf-%d-proto-%d-family-%s", | |
865 | PF_NETLINK, NETLINK_GENERIC, name); | |
866 | down_read(&cb_lock); | |
867 | genl_lock(); | |
868 | res = genl_family_find_byname(name); | |
869 | } | |
870 | #endif | |
871 | err = -ENOENT; | |
872 | } | |
873 | ||
874 | if (res == NULL) | |
875 | return err; | |
876 | ||
877 | if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) { | |
878 | /* family doesn't exist here */ | |
879 | return -ENOENT; | |
880 | } | |
881 | ||
882 | msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq, | |
883 | CTRL_CMD_NEWFAMILY); | |
884 | if (IS_ERR(msg)) | |
885 | return PTR_ERR(msg); | |
886 | ||
887 | return genlmsg_reply(msg, info); | |
888 | } | |
889 | ||
890 | static int genl_ctrl_event(int event, const struct genl_family *family, | |
891 | const struct genl_multicast_group *grp, | |
892 | int grp_id) | |
893 | { | |
894 | struct sk_buff *msg; | |
895 | ||
896 | /* genl is still initialising */ | |
897 | if (!init_net.genl_sock) | |
898 | return 0; | |
899 | ||
900 | switch (event) { | |
901 | case CTRL_CMD_NEWFAMILY: | |
902 | case CTRL_CMD_DELFAMILY: | |
903 | WARN_ON(grp); | |
904 | msg = ctrl_build_family_msg(family, 0, 0, event); | |
905 | break; | |
906 | case CTRL_CMD_NEWMCAST_GRP: | |
907 | case CTRL_CMD_DELMCAST_GRP: | |
908 | BUG_ON(!grp); | |
909 | msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); | |
910 | break; | |
911 | default: | |
912 | return -EINVAL; | |
913 | } | |
914 | ||
915 | if (IS_ERR(msg)) | |
916 | return PTR_ERR(msg); | |
917 | ||
918 | if (!family->netnsok) { | |
919 | genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, | |
920 | 0, GFP_KERNEL); | |
921 | } else { | |
922 | rcu_read_lock(); | |
923 | genlmsg_multicast_allns(&genl_ctrl, msg, 0, | |
924 | 0, GFP_ATOMIC); | |
925 | rcu_read_unlock(); | |
926 | } | |
927 | ||
928 | return 0; | |
929 | } | |
930 | ||
931 | static const struct genl_ops genl_ctrl_ops[] = { | |
932 | { | |
933 | .cmd = CTRL_CMD_GETFAMILY, | |
934 | .doit = ctrl_getfamily, | |
935 | .dumpit = ctrl_dumpfamily, | |
936 | .policy = ctrl_policy, | |
937 | }, | |
938 | }; | |
939 | ||
940 | static const struct genl_multicast_group genl_ctrl_groups[] = { | |
941 | { .name = "notify", }, | |
942 | }; | |
943 | ||
944 | static struct genl_family genl_ctrl __ro_after_init = { | |
945 | .module = THIS_MODULE, | |
946 | .ops = genl_ctrl_ops, | |
947 | .n_ops = ARRAY_SIZE(genl_ctrl_ops), | |
948 | .mcgrps = genl_ctrl_groups, | |
949 | .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), | |
950 | .id = GENL_ID_CTRL, | |
951 | .name = "nlctrl", | |
952 | .version = 0x2, | |
953 | .maxattr = CTRL_ATTR_MAX, | |
954 | .netnsok = true, | |
955 | }; | |
956 | ||
957 | static int genl_bind(struct net *net, int group) | |
958 | { | |
959 | struct genl_family *f; | |
960 | int err = -ENOENT; | |
961 | unsigned int id; | |
962 | ||
963 | down_read(&cb_lock); | |
964 | ||
965 | idr_for_each_entry(&genl_fam_idr, f, id) { | |
966 | if (group >= f->mcgrp_offset && | |
967 | group < f->mcgrp_offset + f->n_mcgrps) { | |
968 | int fam_grp = group - f->mcgrp_offset; | |
969 | ||
970 | if (!f->netnsok && net != &init_net) | |
971 | err = -ENOENT; | |
972 | else if (f->mcast_bind) | |
973 | err = f->mcast_bind(net, fam_grp); | |
974 | else | |
975 | err = 0; | |
976 | break; | |
977 | } | |
978 | } | |
979 | up_read(&cb_lock); | |
980 | ||
981 | return err; | |
982 | } | |
983 | ||
984 | static void genl_unbind(struct net *net, int group) | |
985 | { | |
986 | struct genl_family *f; | |
987 | unsigned int id; | |
988 | ||
989 | down_read(&cb_lock); | |
990 | ||
991 | idr_for_each_entry(&genl_fam_idr, f, id) { | |
992 | if (group >= f->mcgrp_offset && | |
993 | group < f->mcgrp_offset + f->n_mcgrps) { | |
994 | int fam_grp = group - f->mcgrp_offset; | |
995 | ||
996 | if (f->mcast_unbind) | |
997 | f->mcast_unbind(net, fam_grp); | |
998 | break; | |
999 | } | |
1000 | } | |
1001 | up_read(&cb_lock); | |
1002 | } | |
1003 | ||
1004 | static int __net_init genl_pernet_init(struct net *net) | |
1005 | { | |
1006 | struct netlink_kernel_cfg cfg = { | |
1007 | .input = genl_rcv, | |
1008 | .flags = NL_CFG_F_NONROOT_RECV, | |
1009 | .bind = genl_bind, | |
1010 | .unbind = genl_unbind, | |
1011 | }; | |
1012 | ||
1013 | /* we'll bump the group number right afterwards */ | |
1014 | net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg); | |
1015 | ||
1016 | if (!net->genl_sock && net_eq(net, &init_net)) | |
1017 | panic("GENL: Cannot initialize generic netlink\n"); | |
1018 | ||
1019 | if (!net->genl_sock) | |
1020 | return -ENOMEM; | |
1021 | ||
1022 | return 0; | |
1023 | } | |
1024 | ||
1025 | static void __net_exit genl_pernet_exit(struct net *net) | |
1026 | { | |
1027 | netlink_kernel_release(net->genl_sock); | |
1028 | net->genl_sock = NULL; | |
1029 | } | |
1030 | ||
1031 | static struct pernet_operations genl_pernet_ops = { | |
1032 | .init = genl_pernet_init, | |
1033 | .exit = genl_pernet_exit, | |
1034 | }; | |
1035 | ||
1036 | static int __init genl_init(void) | |
1037 | { | |
1038 | int err; | |
1039 | ||
1040 | err = genl_register_family(&genl_ctrl); | |
1041 | if (err < 0) | |
1042 | goto problem; | |
1043 | ||
1044 | err = register_pernet_subsys(&genl_pernet_ops); | |
1045 | if (err) | |
1046 | goto problem; | |
1047 | ||
1048 | return 0; | |
1049 | ||
1050 | problem: | |
1051 | panic("GENL: Cannot register controller: %d\n", err); | |
1052 | } | |
1053 | ||
1054 | subsys_initcall(genl_init); | |
1055 | ||
1056 | /** | |
1057 | * genl_family_attrbuf - return family's attrbuf | |
1058 | * @family: the family | |
1059 | * | |
1060 | * Return the family's attrbuf, while validating that it's | |
1061 | * actually valid to access it. | |
1062 | * | |
1063 | * You cannot use this function with a family that has parallel_ops | |
1064 | * and you can only use it within (pre/post) doit/dumpit callbacks. | |
1065 | */ | |
1066 | struct nlattr **genl_family_attrbuf(const struct genl_family *family) | |
1067 | { | |
1068 | if (!WARN_ON(family->parallel_ops)) | |
1069 | lockdep_assert_held(&genl_mutex); | |
1070 | ||
1071 | return family->attrbuf; | |
1072 | } | |
1073 | EXPORT_SYMBOL(genl_family_attrbuf); | |
1074 | ||
1075 | static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, | |
1076 | gfp_t flags) | |
1077 | { | |
1078 | struct sk_buff *tmp; | |
1079 | struct net *net, *prev = NULL; | |
1080 | int err; | |
1081 | ||
1082 | for_each_net_rcu(net) { | |
1083 | if (prev) { | |
1084 | tmp = skb_clone(skb, flags); | |
1085 | if (!tmp) { | |
1086 | err = -ENOMEM; | |
1087 | goto error; | |
1088 | } | |
1089 | err = nlmsg_multicast(prev->genl_sock, tmp, | |
1090 | portid, group, flags); | |
1091 | if (err) | |
1092 | goto error; | |
1093 | } | |
1094 | ||
1095 | prev = net; | |
1096 | } | |
1097 | ||
1098 | return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); | |
1099 | error: | |
1100 | kfree_skb(skb); | |
1101 | return err; | |
1102 | } | |
1103 | ||
1104 | int genlmsg_multicast_allns(const struct genl_family *family, | |
1105 | struct sk_buff *skb, u32 portid, | |
1106 | unsigned int group, gfp_t flags) | |
1107 | { | |
1108 | if (WARN_ON_ONCE(group >= family->n_mcgrps)) | |
1109 | return -EINVAL; | |
1110 | group = family->mcgrp_offset + group; | |
1111 | return genlmsg_mcast(skb, portid, group, flags); | |
1112 | } | |
1113 | EXPORT_SYMBOL(genlmsg_multicast_allns); | |
1114 | ||
1115 | void genl_notify(const struct genl_family *family, struct sk_buff *skb, | |
1116 | struct genl_info *info, u32 group, gfp_t flags) | |
1117 | { | |
1118 | struct net *net = genl_info_net(info); | |
1119 | struct sock *sk = net->genl_sock; | |
1120 | int report = 0; | |
1121 | ||
1122 | if (info->nlhdr) | |
1123 | report = nlmsg_report(info->nlhdr); | |
1124 | ||
1125 | if (WARN_ON_ONCE(group >= family->n_mcgrps)) | |
1126 | return; | |
1127 | group = family->mcgrp_offset + group; | |
1128 | nlmsg_notify(sk, skb, info->snd_portid, group, report, flags); | |
1129 | } | |
1130 | EXPORT_SYMBOL(genl_notify); |