Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
6 */
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/skbuff.h>
11#include <linux/netlink.h>
12#include <linux/rculist.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/list.h>
16#include <linux/errno.h>
17#include <linux/capability.h>
18#include <net/netlink.h>
19#include <net/sock.h>
20
21#include <net/netfilter/nf_conntrack_helper.h>
22#include <net/netfilter/nf_conntrack_expect.h>
23#include <net/netfilter/nf_conntrack_ecache.h>
24
25#include <linux/netfilter/nfnetlink.h>
26#include <linux/netfilter/nfnetlink_conntrack.h>
27#include <linux/netfilter/nfnetlink_cthelper.h>
28
29MODULE_LICENSE("GPL");
30MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
31MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
32
33struct nfnl_cthelper {
34 struct list_head list;
35 struct nf_conntrack_helper helper;
36};
37
38static LIST_HEAD(nfnl_cthelper_list);
39
40static int
41nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
42 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
43{
44 const struct nf_conn_help *help;
45 struct nf_conntrack_helper *helper;
46
47 help = nfct_help(ct);
48 if (help == NULL)
49 return NF_DROP;
50
51 /* rcu_read_lock()ed by nf_hook_thresh */
52 helper = rcu_dereference(help->helper);
53 if (helper == NULL)
54 return NF_DROP;
55
56 /* This is a user-space helper not yet configured, skip. */
57 if ((helper->flags &
58 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
59 NF_CT_HELPER_F_USERSPACE)
60 return NF_ACCEPT;
61
62 /* If the user-space helper is not available, don't block traffic. */
63 return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
64}
65
66static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
67 [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
68 [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
69};
70
71static int
72nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
73 const struct nlattr *attr)
74{
75 int err;
76 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
77
78 err = nla_parse_nested_deprecated(tb, NFCTH_TUPLE_MAX, attr,
79 nfnl_cthelper_tuple_pol, NULL);
80 if (err < 0)
81 return err;
82
83 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
84 return -EINVAL;
85
86 /* Not all fields are initialized so first zero the tuple */
87 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
88
89 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
90 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
91
92 return 0;
93}
94
95static int
96nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
97{
98 struct nf_conn_help *help = nfct_help(ct);
99
100 if (attr == NULL)
101 return -EINVAL;
102
103 if (help->helper->data_len == 0)
104 return -EINVAL;
105
106 nla_memcpy(help->data, attr, sizeof(help->data));
107 return 0;
108}
109
110static int
111nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
112{
113 const struct nf_conn_help *help = nfct_help(ct);
114
115 if (help->helper->data_len &&
116 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
117 goto nla_put_failure;
118
119 return 0;
120
121nla_put_failure:
122 return -ENOSPC;
123}
124
125static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
126 [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
127 .len = NF_CT_HELPER_NAME_LEN-1 },
128 [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
129 [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
130};
131
132static int
133nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
134 const struct nlattr *attr)
135{
136 int err;
137 struct nlattr *tb[NFCTH_POLICY_MAX+1];
138
139 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
140 nfnl_cthelper_expect_pol, NULL);
141 if (err < 0)
142 return err;
143
144 if (!tb[NFCTH_POLICY_NAME] ||
145 !tb[NFCTH_POLICY_EXPECT_MAX] ||
146 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
147 return -EINVAL;
148
149 nla_strscpy(expect_policy->name,
150 tb[NFCTH_POLICY_NAME], NF_CT_HELPER_NAME_LEN);
151 expect_policy->max_expected =
152 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
153 if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
154 return -EINVAL;
155
156 expect_policy->timeout =
157 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
158
159 return 0;
160}
161
162static const struct nla_policy
163nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
164 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
165};
166
167static int
168nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
169 const struct nlattr *attr)
170{
171 int i, ret;
172 struct nf_conntrack_expect_policy *expect_policy;
173 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
174 unsigned int class_max;
175
176 ret = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
177 nfnl_cthelper_expect_policy_set,
178 NULL);
179 if (ret < 0)
180 return ret;
181
182 if (!tb[NFCTH_POLICY_SET_NUM])
183 return -EINVAL;
184
185 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
186 if (class_max == 0)
187 return -EINVAL;
188 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
189 return -EOVERFLOW;
190
191 expect_policy = kcalloc(class_max,
192 sizeof(struct nf_conntrack_expect_policy),
193 GFP_KERNEL);
194 if (expect_policy == NULL)
195 return -ENOMEM;
196
197 for (i = 0; i < class_max; i++) {
198 if (!tb[NFCTH_POLICY_SET+i])
199 goto err;
200
201 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
202 tb[NFCTH_POLICY_SET+i]);
203 if (ret < 0)
204 goto err;
205 }
206
207 helper->expect_class_max = class_max - 1;
208 helper->expect_policy = expect_policy;
209 return 0;
210err:
211 kfree(expect_policy);
212 return -EINVAL;
213}
214
215static int
216nfnl_cthelper_create(const struct nlattr * const tb[],
217 struct nf_conntrack_tuple *tuple)
218{
219 struct nf_conntrack_helper *helper;
220 struct nfnl_cthelper *nfcth;
221 unsigned int size;
222 int ret;
223
224 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
225 return -EINVAL;
226
227 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
228 if (nfcth == NULL)
229 return -ENOMEM;
230 helper = &nfcth->helper;
231
232 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
233 if (ret < 0)
234 goto err1;
235
236 nla_strscpy(helper->name,
237 tb[NFCTH_NAME], NF_CT_HELPER_NAME_LEN);
238 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
239 if (size > sizeof_field(struct nf_conn_help, data)) {
240 ret = -ENOMEM;
241 goto err2;
242 }
243 helper->data_len = size;
244
245 helper->flags |= NF_CT_HELPER_F_USERSPACE;
246 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
247
248 helper->me = THIS_MODULE;
249 helper->help = nfnl_userspace_cthelper;
250 helper->from_nlattr = nfnl_cthelper_from_nlattr;
251 helper->to_nlattr = nfnl_cthelper_to_nlattr;
252
253 /* Default to queue number zero, this can be updated at any time. */
254 if (tb[NFCTH_QUEUE_NUM])
255 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
256
257 if (tb[NFCTH_STATUS]) {
258 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
259
260 switch(status) {
261 case NFCT_HELPER_STATUS_ENABLED:
262 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
263 break;
264 case NFCT_HELPER_STATUS_DISABLED:
265 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
266 break;
267 }
268 }
269
270 ret = nf_conntrack_helper_register(helper);
271 if (ret < 0)
272 goto err2;
273
274 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
275 return 0;
276err2:
277 kfree(helper->expect_policy);
278err1:
279 kfree(nfcth);
280 return ret;
281}
282
283static int
284nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
285 struct nf_conntrack_expect_policy *new_policy,
286 const struct nlattr *attr)
287{
288 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
289 int err;
290
291 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
292 nfnl_cthelper_expect_pol, NULL);
293 if (err < 0)
294 return err;
295
296 if (!tb[NFCTH_POLICY_NAME] ||
297 !tb[NFCTH_POLICY_EXPECT_MAX] ||
298 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
299 return -EINVAL;
300
301 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
302 return -EBUSY;
303
304 new_policy->max_expected =
305 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
306 if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
307 return -EINVAL;
308
309 new_policy->timeout =
310 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
311
312 return 0;
313}
314
315static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
316 struct nf_conntrack_helper *helper)
317{
318 struct nf_conntrack_expect_policy *new_policy;
319 struct nf_conntrack_expect_policy *policy;
320 int i, ret = 0;
321
322 new_policy = kmalloc_array(helper->expect_class_max + 1,
323 sizeof(*new_policy), GFP_KERNEL);
324 if (!new_policy)
325 return -ENOMEM;
326
327 /* Check first that all policy attributes are well-formed, so we don't
328 * leave things in inconsistent state on errors.
329 */
330 for (i = 0; i < helper->expect_class_max + 1; i++) {
331
332 if (!tb[NFCTH_POLICY_SET + i]) {
333 ret = -EINVAL;
334 goto err;
335 }
336
337 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
338 &new_policy[i],
339 tb[NFCTH_POLICY_SET + i]);
340 if (ret < 0)
341 goto err;
342 }
343 /* Now we can safely update them. */
344 for (i = 0; i < helper->expect_class_max + 1; i++) {
345 policy = (struct nf_conntrack_expect_policy *)
346 &helper->expect_policy[i];
347 policy->max_expected = new_policy->max_expected;
348 policy->timeout = new_policy->timeout;
349 }
350
351err:
352 kfree(new_policy);
353 return ret;
354}
355
356static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
357 const struct nlattr *attr)
358{
359 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
360 unsigned int class_max;
361 int err;
362
363 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
364 nfnl_cthelper_expect_policy_set,
365 NULL);
366 if (err < 0)
367 return err;
368
369 if (!tb[NFCTH_POLICY_SET_NUM])
370 return -EINVAL;
371
372 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
373 if (helper->expect_class_max + 1 != class_max)
374 return -EBUSY;
375
376 return nfnl_cthelper_update_policy_all(tb, helper);
377}
378
379static int
380nfnl_cthelper_update(const struct nlattr * const tb[],
381 struct nf_conntrack_helper *helper)
382{
383 u32 size;
384 int ret;
385
386 if (tb[NFCTH_PRIV_DATA_LEN]) {
387 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
388 if (size != helper->data_len)
389 return -EBUSY;
390 }
391
392 if (tb[NFCTH_POLICY]) {
393 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
394 if (ret < 0)
395 return ret;
396 }
397 if (tb[NFCTH_QUEUE_NUM])
398 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
399
400 if (tb[NFCTH_STATUS]) {
401 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
402
403 switch(status) {
404 case NFCT_HELPER_STATUS_ENABLED:
405 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
406 break;
407 case NFCT_HELPER_STATUS_DISABLED:
408 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
409 break;
410 }
411 }
412 return 0;
413}
414
415static int nfnl_cthelper_new(struct sk_buff *skb, const struct nfnl_info *info,
416 const struct nlattr * const tb[])
417{
418 const char *helper_name;
419 struct nf_conntrack_helper *cur, *helper = NULL;
420 struct nf_conntrack_tuple tuple;
421 struct nfnl_cthelper *nlcth;
422 int ret = 0;
423
424 if (!capable(CAP_NET_ADMIN))
425 return -EPERM;
426
427 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
428 return -EINVAL;
429
430 helper_name = nla_data(tb[NFCTH_NAME]);
431
432 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
433 if (ret < 0)
434 return ret;
435
436 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
437 cur = &nlcth->helper;
438
439 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
440 continue;
441
442 if ((tuple.src.l3num != cur->tuple.src.l3num ||
443 tuple.dst.protonum != cur->tuple.dst.protonum))
444 continue;
445
446 if (info->nlh->nlmsg_flags & NLM_F_EXCL)
447 return -EEXIST;
448
449 helper = cur;
450 break;
451 }
452
453 if (helper == NULL)
454 ret = nfnl_cthelper_create(tb, &tuple);
455 else
456 ret = nfnl_cthelper_update(tb, helper);
457
458 return ret;
459}
460
461static int
462nfnl_cthelper_dump_tuple(struct sk_buff *skb,
463 struct nf_conntrack_helper *helper)
464{
465 struct nlattr *nest_parms;
466
467 nest_parms = nla_nest_start(skb, NFCTH_TUPLE);
468 if (nest_parms == NULL)
469 goto nla_put_failure;
470
471 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
472 htons(helper->tuple.src.l3num)))
473 goto nla_put_failure;
474
475 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
476 goto nla_put_failure;
477
478 nla_nest_end(skb, nest_parms);
479 return 0;
480
481nla_put_failure:
482 return -1;
483}
484
485static int
486nfnl_cthelper_dump_policy(struct sk_buff *skb,
487 struct nf_conntrack_helper *helper)
488{
489 int i;
490 struct nlattr *nest_parms1, *nest_parms2;
491
492 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY);
493 if (nest_parms1 == NULL)
494 goto nla_put_failure;
495
496 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
497 htonl(helper->expect_class_max + 1)))
498 goto nla_put_failure;
499
500 for (i = 0; i < helper->expect_class_max + 1; i++) {
501 nest_parms2 = nla_nest_start(skb, (NFCTH_POLICY_SET + i));
502 if (nest_parms2 == NULL)
503 goto nla_put_failure;
504
505 if (nla_put_string(skb, NFCTH_POLICY_NAME,
506 helper->expect_policy[i].name))
507 goto nla_put_failure;
508
509 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
510 htonl(helper->expect_policy[i].max_expected)))
511 goto nla_put_failure;
512
513 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
514 htonl(helper->expect_policy[i].timeout)))
515 goto nla_put_failure;
516
517 nla_nest_end(skb, nest_parms2);
518 }
519 nla_nest_end(skb, nest_parms1);
520 return 0;
521
522nla_put_failure:
523 return -1;
524}
525
526static int
527nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
528 int event, struct nf_conntrack_helper *helper)
529{
530 struct nlmsghdr *nlh;
531 unsigned int flags = portid ? NLM_F_MULTI : 0;
532 int status;
533
534 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
535 nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
536 NFNETLINK_V0, 0);
537 if (!nlh)
538 goto nlmsg_failure;
539
540 if (nla_put_string(skb, NFCTH_NAME, helper->name))
541 goto nla_put_failure;
542
543 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
544 goto nla_put_failure;
545
546 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
547 goto nla_put_failure;
548
549 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
550 goto nla_put_failure;
551
552 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
553 goto nla_put_failure;
554
555 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
556 status = NFCT_HELPER_STATUS_ENABLED;
557 else
558 status = NFCT_HELPER_STATUS_DISABLED;
559
560 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
561 goto nla_put_failure;
562
563 nlmsg_end(skb, nlh);
564 return skb->len;
565
566nlmsg_failure:
567nla_put_failure:
568 nlmsg_cancel(skb, nlh);
569 return -1;
570}
571
572static int
573nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
574{
575 struct nf_conntrack_helper *cur, *last;
576
577 rcu_read_lock();
578 last = (struct nf_conntrack_helper *)cb->args[1];
579 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
580restart:
581 hlist_for_each_entry_rcu(cur,
582 &nf_ct_helper_hash[cb->args[0]], hnode) {
583
584 /* skip non-userspace conntrack helpers. */
585 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
586 continue;
587
588 if (cb->args[1]) {
589 if (cur != last)
590 continue;
591 cb->args[1] = 0;
592 }
593 if (nfnl_cthelper_fill_info(skb,
594 NETLINK_CB(cb->skb).portid,
595 cb->nlh->nlmsg_seq,
596 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
597 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
598 cb->args[1] = (unsigned long)cur;
599 goto out;
600 }
601 }
602 }
603 if (cb->args[1]) {
604 cb->args[1] = 0;
605 goto restart;
606 }
607out:
608 rcu_read_unlock();
609 return skb->len;
610}
611
612static int nfnl_cthelper_get(struct sk_buff *skb, const struct nfnl_info *info,
613 const struct nlattr * const tb[])
614{
615 int ret = -ENOENT;
616 struct nf_conntrack_helper *cur;
617 struct sk_buff *skb2;
618 char *helper_name = NULL;
619 struct nf_conntrack_tuple tuple;
620 struct nfnl_cthelper *nlcth;
621 bool tuple_set = false;
622
623 if (!capable(CAP_NET_ADMIN))
624 return -EPERM;
625
626 if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
627 struct netlink_dump_control c = {
628 .dump = nfnl_cthelper_dump_table,
629 };
630 return netlink_dump_start(info->sk, skb, info->nlh, &c);
631 }
632
633 if (tb[NFCTH_NAME])
634 helper_name = nla_data(tb[NFCTH_NAME]);
635
636 if (tb[NFCTH_TUPLE]) {
637 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
638 if (ret < 0)
639 return ret;
640
641 tuple_set = true;
642 }
643
644 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
645 cur = &nlcth->helper;
646 if (helper_name &&
647 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
648 continue;
649
650 if (tuple_set &&
651 (tuple.src.l3num != cur->tuple.src.l3num ||
652 tuple.dst.protonum != cur->tuple.dst.protonum))
653 continue;
654
655 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
656 if (skb2 == NULL) {
657 ret = -ENOMEM;
658 break;
659 }
660
661 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
662 info->nlh->nlmsg_seq,
663 NFNL_MSG_TYPE(info->nlh->nlmsg_type),
664 NFNL_MSG_CTHELPER_NEW, cur);
665 if (ret <= 0) {
666 kfree_skb(skb2);
667 break;
668 }
669
670 ret = nfnetlink_unicast(skb2, info->net, NETLINK_CB(skb).portid);
671 break;
672 }
673
674 return ret;
675}
676
677static int nfnl_cthelper_del(struct sk_buff *skb, const struct nfnl_info *info,
678 const struct nlattr * const tb[])
679{
680 char *helper_name = NULL;
681 struct nf_conntrack_helper *cur;
682 struct nf_conntrack_tuple tuple;
683 bool tuple_set = false, found = false;
684 struct nfnl_cthelper *nlcth, *n;
685 int j = 0, ret;
686
687 if (!capable(CAP_NET_ADMIN))
688 return -EPERM;
689
690 if (tb[NFCTH_NAME])
691 helper_name = nla_data(tb[NFCTH_NAME]);
692
693 if (tb[NFCTH_TUPLE]) {
694 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
695 if (ret < 0)
696 return ret;
697
698 tuple_set = true;
699 }
700
701 ret = -ENOENT;
702 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
703 cur = &nlcth->helper;
704 j++;
705
706 if (helper_name &&
707 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
708 continue;
709
710 if (tuple_set &&
711 (tuple.src.l3num != cur->tuple.src.l3num ||
712 tuple.dst.protonum != cur->tuple.dst.protonum))
713 continue;
714
715 if (refcount_dec_if_one(&cur->refcnt)) {
716 found = true;
717 nf_conntrack_helper_unregister(cur);
718 kfree(cur->expect_policy);
719
720 list_del(&nlcth->list);
721 kfree(nlcth);
722 } else {
723 ret = -EBUSY;
724 }
725 }
726
727 /* Make sure we return success if we flush and there is no helpers */
728 return (found || j == 0) ? 0 : ret;
729}
730
731static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
732 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
733 .len = NF_CT_HELPER_NAME_LEN-1 },
734 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
735 [NFCTH_PRIV_DATA_LEN] = { .type = NLA_U32, },
736 [NFCTH_STATUS] = { .type = NLA_U32, },
737};
738
739static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
740 [NFNL_MSG_CTHELPER_NEW] = {
741 .call = nfnl_cthelper_new,
742 .type = NFNL_CB_MUTEX,
743 .attr_count = NFCTH_MAX,
744 .policy = nfnl_cthelper_policy
745 },
746 [NFNL_MSG_CTHELPER_GET] = {
747 .call = nfnl_cthelper_get,
748 .type = NFNL_CB_MUTEX,
749 .attr_count = NFCTH_MAX,
750 .policy = nfnl_cthelper_policy
751 },
752 [NFNL_MSG_CTHELPER_DEL] = {
753 .call = nfnl_cthelper_del,
754 .type = NFNL_CB_MUTEX,
755 .attr_count = NFCTH_MAX,
756 .policy = nfnl_cthelper_policy
757 },
758};
759
760static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
761 .name = "cthelper",
762 .subsys_id = NFNL_SUBSYS_CTHELPER,
763 .cb_count = NFNL_MSG_CTHELPER_MAX,
764 .cb = nfnl_cthelper_cb,
765};
766
767MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
768
769static int __init nfnl_cthelper_init(void)
770{
771 int ret;
772
773 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
774 if (ret < 0) {
775 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
776 goto err_out;
777 }
778 return 0;
779err_out:
780 return ret;
781}
782
783static void __exit nfnl_cthelper_exit(void)
784{
785 struct nf_conntrack_helper *cur;
786 struct nfnl_cthelper *nlcth, *n;
787
788 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
789
790 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
791 cur = &nlcth->helper;
792
793 nf_conntrack_helper_unregister(cur);
794 kfree(cur->expect_policy);
795 kfree(nlcth);
796 }
797}
798
799module_init(nfnl_cthelper_init);
800module_exit(nfnl_cthelper_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
6 */
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/skbuff.h>
11#include <linux/netlink.h>
12#include <linux/rculist.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/list.h>
16#include <linux/errno.h>
17#include <linux/capability.h>
18#include <net/netlink.h>
19#include <net/sock.h>
20
21#include <net/netfilter/nf_conntrack_helper.h>
22#include <net/netfilter/nf_conntrack_expect.h>
23#include <net/netfilter/nf_conntrack_ecache.h>
24
25#include <linux/netfilter/nfnetlink.h>
26#include <linux/netfilter/nfnetlink_conntrack.h>
27#include <linux/netfilter/nfnetlink_cthelper.h>
28
29MODULE_LICENSE("GPL");
30MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
31MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
32
33struct nfnl_cthelper {
34 struct list_head list;
35 struct nf_conntrack_helper helper;
36};
37
38static LIST_HEAD(nfnl_cthelper_list);
39
40static int
41nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
42 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
43{
44 const struct nf_conn_help *help;
45 struct nf_conntrack_helper *helper;
46
47 help = nfct_help(ct);
48 if (help == NULL)
49 return NF_DROP;
50
51 /* rcu_read_lock()ed by nf_hook_thresh */
52 helper = rcu_dereference(help->helper);
53 if (helper == NULL)
54 return NF_DROP;
55
56 /* This is a user-space helper not yet configured, skip. */
57 if ((helper->flags &
58 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
59 NF_CT_HELPER_F_USERSPACE)
60 return NF_ACCEPT;
61
62 /* If the user-space helper is not available, don't block traffic. */
63 return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
64}
65
66static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
67 [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
68 [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
69};
70
71static int
72nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
73 const struct nlattr *attr)
74{
75 int err;
76 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
77
78 err = nla_parse_nested_deprecated(tb, NFCTH_TUPLE_MAX, attr,
79 nfnl_cthelper_tuple_pol, NULL);
80 if (err < 0)
81 return err;
82
83 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
84 return -EINVAL;
85
86 /* Not all fields are initialized so first zero the tuple */
87 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
88
89 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
90 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
91
92 return 0;
93}
94
95static int
96nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
97{
98 struct nf_conn_help *help = nfct_help(ct);
99
100 if (attr == NULL)
101 return -EINVAL;
102
103 if (help->helper->data_len == 0)
104 return -EINVAL;
105
106 nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
107 return 0;
108}
109
110static int
111nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
112{
113 const struct nf_conn_help *help = nfct_help(ct);
114
115 if (help->helper->data_len &&
116 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
117 goto nla_put_failure;
118
119 return 0;
120
121nla_put_failure:
122 return -ENOSPC;
123}
124
125static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
126 [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
127 .len = NF_CT_HELPER_NAME_LEN-1 },
128 [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
129 [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
130};
131
132static int
133nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
134 const struct nlattr *attr)
135{
136 int err;
137 struct nlattr *tb[NFCTH_POLICY_MAX+1];
138
139 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
140 nfnl_cthelper_expect_pol, NULL);
141 if (err < 0)
142 return err;
143
144 if (!tb[NFCTH_POLICY_NAME] ||
145 !tb[NFCTH_POLICY_EXPECT_MAX] ||
146 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
147 return -EINVAL;
148
149 nla_strlcpy(expect_policy->name,
150 tb[NFCTH_POLICY_NAME], NF_CT_HELPER_NAME_LEN);
151 expect_policy->max_expected =
152 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
153 if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
154 return -EINVAL;
155
156 expect_policy->timeout =
157 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
158
159 return 0;
160}
161
162static const struct nla_policy
163nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
164 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
165};
166
167static int
168nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
169 const struct nlattr *attr)
170{
171 int i, ret;
172 struct nf_conntrack_expect_policy *expect_policy;
173 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
174 unsigned int class_max;
175
176 ret = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
177 nfnl_cthelper_expect_policy_set,
178 NULL);
179 if (ret < 0)
180 return ret;
181
182 if (!tb[NFCTH_POLICY_SET_NUM])
183 return -EINVAL;
184
185 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
186 if (class_max == 0)
187 return -EINVAL;
188 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
189 return -EOVERFLOW;
190
191 expect_policy = kcalloc(class_max,
192 sizeof(struct nf_conntrack_expect_policy),
193 GFP_KERNEL);
194 if (expect_policy == NULL)
195 return -ENOMEM;
196
197 for (i = 0; i < class_max; i++) {
198 if (!tb[NFCTH_POLICY_SET+i])
199 goto err;
200
201 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
202 tb[NFCTH_POLICY_SET+i]);
203 if (ret < 0)
204 goto err;
205 }
206
207 helper->expect_class_max = class_max - 1;
208 helper->expect_policy = expect_policy;
209 return 0;
210err:
211 kfree(expect_policy);
212 return -EINVAL;
213}
214
215static int
216nfnl_cthelper_create(const struct nlattr * const tb[],
217 struct nf_conntrack_tuple *tuple)
218{
219 struct nf_conntrack_helper *helper;
220 struct nfnl_cthelper *nfcth;
221 unsigned int size;
222 int ret;
223
224 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
225 return -EINVAL;
226
227 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
228 if (nfcth == NULL)
229 return -ENOMEM;
230 helper = &nfcth->helper;
231
232 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
233 if (ret < 0)
234 goto err1;
235
236 nla_strlcpy(helper->name,
237 tb[NFCTH_NAME], NF_CT_HELPER_NAME_LEN);
238 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
239 if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
240 ret = -ENOMEM;
241 goto err2;
242 }
243
244 helper->flags |= NF_CT_HELPER_F_USERSPACE;
245 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
246
247 helper->me = THIS_MODULE;
248 helper->help = nfnl_userspace_cthelper;
249 helper->from_nlattr = nfnl_cthelper_from_nlattr;
250 helper->to_nlattr = nfnl_cthelper_to_nlattr;
251
252 /* Default to queue number zero, this can be updated at any time. */
253 if (tb[NFCTH_QUEUE_NUM])
254 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
255
256 if (tb[NFCTH_STATUS]) {
257 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
258
259 switch(status) {
260 case NFCT_HELPER_STATUS_ENABLED:
261 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
262 break;
263 case NFCT_HELPER_STATUS_DISABLED:
264 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
265 break;
266 }
267 }
268
269 ret = nf_conntrack_helper_register(helper);
270 if (ret < 0)
271 goto err2;
272
273 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
274 return 0;
275err2:
276 kfree(helper->expect_policy);
277err1:
278 kfree(nfcth);
279 return ret;
280}
281
282static int
283nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
284 struct nf_conntrack_expect_policy *new_policy,
285 const struct nlattr *attr)
286{
287 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
288 int err;
289
290 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
291 nfnl_cthelper_expect_pol, NULL);
292 if (err < 0)
293 return err;
294
295 if (!tb[NFCTH_POLICY_NAME] ||
296 !tb[NFCTH_POLICY_EXPECT_MAX] ||
297 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
298 return -EINVAL;
299
300 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
301 return -EBUSY;
302
303 new_policy->max_expected =
304 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
305 if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
306 return -EINVAL;
307
308 new_policy->timeout =
309 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
310
311 return 0;
312}
313
314static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
315 struct nf_conntrack_helper *helper)
316{
317 struct nf_conntrack_expect_policy *new_policy;
318 struct nf_conntrack_expect_policy *policy;
319 int i, ret = 0;
320
321 new_policy = kmalloc_array(helper->expect_class_max + 1,
322 sizeof(*new_policy), GFP_KERNEL);
323 if (!new_policy)
324 return -ENOMEM;
325
326 /* Check first that all policy attributes are well-formed, so we don't
327 * leave things in inconsistent state on errors.
328 */
329 for (i = 0; i < helper->expect_class_max + 1; i++) {
330
331 if (!tb[NFCTH_POLICY_SET + i]) {
332 ret = -EINVAL;
333 goto err;
334 }
335
336 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
337 &new_policy[i],
338 tb[NFCTH_POLICY_SET + i]);
339 if (ret < 0)
340 goto err;
341 }
342 /* Now we can safely update them. */
343 for (i = 0; i < helper->expect_class_max + 1; i++) {
344 policy = (struct nf_conntrack_expect_policy *)
345 &helper->expect_policy[i];
346 policy->max_expected = new_policy->max_expected;
347 policy->timeout = new_policy->timeout;
348 }
349
350err:
351 kfree(new_policy);
352 return ret;
353}
354
355static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
356 const struct nlattr *attr)
357{
358 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
359 unsigned int class_max;
360 int err;
361
362 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
363 nfnl_cthelper_expect_policy_set,
364 NULL);
365 if (err < 0)
366 return err;
367
368 if (!tb[NFCTH_POLICY_SET_NUM])
369 return -EINVAL;
370
371 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
372 if (helper->expect_class_max + 1 != class_max)
373 return -EBUSY;
374
375 return nfnl_cthelper_update_policy_all(tb, helper);
376}
377
378static int
379nfnl_cthelper_update(const struct nlattr * const tb[],
380 struct nf_conntrack_helper *helper)
381{
382 int ret;
383
384 if (tb[NFCTH_PRIV_DATA_LEN])
385 return -EBUSY;
386
387 if (tb[NFCTH_POLICY]) {
388 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
389 if (ret < 0)
390 return ret;
391 }
392 if (tb[NFCTH_QUEUE_NUM])
393 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
394
395 if (tb[NFCTH_STATUS]) {
396 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
397
398 switch(status) {
399 case NFCT_HELPER_STATUS_ENABLED:
400 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
401 break;
402 case NFCT_HELPER_STATUS_DISABLED:
403 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
404 break;
405 }
406 }
407 return 0;
408}
409
410static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
411 struct sk_buff *skb, const struct nlmsghdr *nlh,
412 const struct nlattr * const tb[],
413 struct netlink_ext_ack *extack)
414{
415 const char *helper_name;
416 struct nf_conntrack_helper *cur, *helper = NULL;
417 struct nf_conntrack_tuple tuple;
418 struct nfnl_cthelper *nlcth;
419 int ret = 0;
420
421 if (!capable(CAP_NET_ADMIN))
422 return -EPERM;
423
424 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
425 return -EINVAL;
426
427 helper_name = nla_data(tb[NFCTH_NAME]);
428
429 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
430 if (ret < 0)
431 return ret;
432
433 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
434 cur = &nlcth->helper;
435
436 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
437 continue;
438
439 if ((tuple.src.l3num != cur->tuple.src.l3num ||
440 tuple.dst.protonum != cur->tuple.dst.protonum))
441 continue;
442
443 if (nlh->nlmsg_flags & NLM_F_EXCL)
444 return -EEXIST;
445
446 helper = cur;
447 break;
448 }
449
450 if (helper == NULL)
451 ret = nfnl_cthelper_create(tb, &tuple);
452 else
453 ret = nfnl_cthelper_update(tb, helper);
454
455 return ret;
456}
457
458static int
459nfnl_cthelper_dump_tuple(struct sk_buff *skb,
460 struct nf_conntrack_helper *helper)
461{
462 struct nlattr *nest_parms;
463
464 nest_parms = nla_nest_start(skb, NFCTH_TUPLE);
465 if (nest_parms == NULL)
466 goto nla_put_failure;
467
468 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
469 htons(helper->tuple.src.l3num)))
470 goto nla_put_failure;
471
472 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
473 goto nla_put_failure;
474
475 nla_nest_end(skb, nest_parms);
476 return 0;
477
478nla_put_failure:
479 return -1;
480}
481
482static int
483nfnl_cthelper_dump_policy(struct sk_buff *skb,
484 struct nf_conntrack_helper *helper)
485{
486 int i;
487 struct nlattr *nest_parms1, *nest_parms2;
488
489 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY);
490 if (nest_parms1 == NULL)
491 goto nla_put_failure;
492
493 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
494 htonl(helper->expect_class_max + 1)))
495 goto nla_put_failure;
496
497 for (i = 0; i < helper->expect_class_max + 1; i++) {
498 nest_parms2 = nla_nest_start(skb, (NFCTH_POLICY_SET + i));
499 if (nest_parms2 == NULL)
500 goto nla_put_failure;
501
502 if (nla_put_string(skb, NFCTH_POLICY_NAME,
503 helper->expect_policy[i].name))
504 goto nla_put_failure;
505
506 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
507 htonl(helper->expect_policy[i].max_expected)))
508 goto nla_put_failure;
509
510 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
511 htonl(helper->expect_policy[i].timeout)))
512 goto nla_put_failure;
513
514 nla_nest_end(skb, nest_parms2);
515 }
516 nla_nest_end(skb, nest_parms1);
517 return 0;
518
519nla_put_failure:
520 return -1;
521}
522
523static int
524nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
525 int event, struct nf_conntrack_helper *helper)
526{
527 struct nlmsghdr *nlh;
528 struct nfgenmsg *nfmsg;
529 unsigned int flags = portid ? NLM_F_MULTI : 0;
530 int status;
531
532 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
533 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
534 if (nlh == NULL)
535 goto nlmsg_failure;
536
537 nfmsg = nlmsg_data(nlh);
538 nfmsg->nfgen_family = AF_UNSPEC;
539 nfmsg->version = NFNETLINK_V0;
540 nfmsg->res_id = 0;
541
542 if (nla_put_string(skb, NFCTH_NAME, helper->name))
543 goto nla_put_failure;
544
545 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
546 goto nla_put_failure;
547
548 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
549 goto nla_put_failure;
550
551 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
552 goto nla_put_failure;
553
554 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
555 goto nla_put_failure;
556
557 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
558 status = NFCT_HELPER_STATUS_ENABLED;
559 else
560 status = NFCT_HELPER_STATUS_DISABLED;
561
562 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
563 goto nla_put_failure;
564
565 nlmsg_end(skb, nlh);
566 return skb->len;
567
568nlmsg_failure:
569nla_put_failure:
570 nlmsg_cancel(skb, nlh);
571 return -1;
572}
573
574static int
575nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
576{
577 struct nf_conntrack_helper *cur, *last;
578
579 rcu_read_lock();
580 last = (struct nf_conntrack_helper *)cb->args[1];
581 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
582restart:
583 hlist_for_each_entry_rcu(cur,
584 &nf_ct_helper_hash[cb->args[0]], hnode) {
585
586 /* skip non-userspace conntrack helpers. */
587 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
588 continue;
589
590 if (cb->args[1]) {
591 if (cur != last)
592 continue;
593 cb->args[1] = 0;
594 }
595 if (nfnl_cthelper_fill_info(skb,
596 NETLINK_CB(cb->skb).portid,
597 cb->nlh->nlmsg_seq,
598 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
599 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
600 cb->args[1] = (unsigned long)cur;
601 goto out;
602 }
603 }
604 }
605 if (cb->args[1]) {
606 cb->args[1] = 0;
607 goto restart;
608 }
609out:
610 rcu_read_unlock();
611 return skb->len;
612}
613
614static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
615 struct sk_buff *skb, const struct nlmsghdr *nlh,
616 const struct nlattr * const tb[],
617 struct netlink_ext_ack *extack)
618{
619 int ret = -ENOENT;
620 struct nf_conntrack_helper *cur;
621 struct sk_buff *skb2;
622 char *helper_name = NULL;
623 struct nf_conntrack_tuple tuple;
624 struct nfnl_cthelper *nlcth;
625 bool tuple_set = false;
626
627 if (!capable(CAP_NET_ADMIN))
628 return -EPERM;
629
630 if (nlh->nlmsg_flags & NLM_F_DUMP) {
631 struct netlink_dump_control c = {
632 .dump = nfnl_cthelper_dump_table,
633 };
634 return netlink_dump_start(nfnl, skb, nlh, &c);
635 }
636
637 if (tb[NFCTH_NAME])
638 helper_name = nla_data(tb[NFCTH_NAME]);
639
640 if (tb[NFCTH_TUPLE]) {
641 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
642 if (ret < 0)
643 return ret;
644
645 tuple_set = true;
646 }
647
648 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
649 cur = &nlcth->helper;
650 if (helper_name &&
651 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
652 continue;
653
654 if (tuple_set &&
655 (tuple.src.l3num != cur->tuple.src.l3num ||
656 tuple.dst.protonum != cur->tuple.dst.protonum))
657 continue;
658
659 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
660 if (skb2 == NULL) {
661 ret = -ENOMEM;
662 break;
663 }
664
665 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
666 nlh->nlmsg_seq,
667 NFNL_MSG_TYPE(nlh->nlmsg_type),
668 NFNL_MSG_CTHELPER_NEW, cur);
669 if (ret <= 0) {
670 kfree_skb(skb2);
671 break;
672 }
673
674 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
675 MSG_DONTWAIT);
676 if (ret > 0)
677 ret = 0;
678
679 /* this avoids a loop in nfnetlink. */
680 return ret == -EAGAIN ? -ENOBUFS : ret;
681 }
682 return ret;
683}
684
685static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
686 struct sk_buff *skb, const struct nlmsghdr *nlh,
687 const struct nlattr * const tb[],
688 struct netlink_ext_ack *extack)
689{
690 char *helper_name = NULL;
691 struct nf_conntrack_helper *cur;
692 struct nf_conntrack_tuple tuple;
693 bool tuple_set = false, found = false;
694 struct nfnl_cthelper *nlcth, *n;
695 int j = 0, ret;
696
697 if (!capable(CAP_NET_ADMIN))
698 return -EPERM;
699
700 if (tb[NFCTH_NAME])
701 helper_name = nla_data(tb[NFCTH_NAME]);
702
703 if (tb[NFCTH_TUPLE]) {
704 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
705 if (ret < 0)
706 return ret;
707
708 tuple_set = true;
709 }
710
711 ret = -ENOENT;
712 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
713 cur = &nlcth->helper;
714 j++;
715
716 if (helper_name &&
717 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
718 continue;
719
720 if (tuple_set &&
721 (tuple.src.l3num != cur->tuple.src.l3num ||
722 tuple.dst.protonum != cur->tuple.dst.protonum))
723 continue;
724
725 if (refcount_dec_if_one(&cur->refcnt)) {
726 found = true;
727 nf_conntrack_helper_unregister(cur);
728 kfree(cur->expect_policy);
729
730 list_del(&nlcth->list);
731 kfree(nlcth);
732 } else {
733 ret = -EBUSY;
734 }
735 }
736
737 /* Make sure we return success if we flush and there is no helpers */
738 return (found || j == 0) ? 0 : ret;
739}
740
741static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
742 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
743 .len = NF_CT_HELPER_NAME_LEN-1 },
744 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
745};
746
747static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
748 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
749 .attr_count = NFCTH_MAX,
750 .policy = nfnl_cthelper_policy },
751 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
752 .attr_count = NFCTH_MAX,
753 .policy = nfnl_cthelper_policy },
754 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
755 .attr_count = NFCTH_MAX,
756 .policy = nfnl_cthelper_policy },
757};
758
759static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
760 .name = "cthelper",
761 .subsys_id = NFNL_SUBSYS_CTHELPER,
762 .cb_count = NFNL_MSG_CTHELPER_MAX,
763 .cb = nfnl_cthelper_cb,
764};
765
766MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
767
768static int __init nfnl_cthelper_init(void)
769{
770 int ret;
771
772 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
773 if (ret < 0) {
774 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
775 goto err_out;
776 }
777 return 0;
778err_out:
779 return ret;
780}
781
782static void __exit nfnl_cthelper_exit(void)
783{
784 struct nf_conntrack_helper *cur;
785 struct nfnl_cthelper *nlcth, *n;
786
787 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
788
789 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
790 cur = &nlcth->helper;
791
792 nf_conntrack_helper_unregister(cur);
793 kfree(cur->expect_policy);
794 kfree(nlcth);
795 }
796}
797
798module_init(nfnl_cthelper_init);
799module_exit(nfnl_cthelper_exit);