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