1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
5 * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
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>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_expect.h>
23 #include <net/netfilter/nf_conntrack_ecache.h>
25 #include <linux/netfilter/nfnetlink.h>
26 #include <linux/netfilter/nfnetlink_conntrack.h>
27 #include <linux/netfilter/nfnetlink_cthelper.h>
29 MODULE_LICENSE("GPL");
30 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
31 MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
33 struct nfnl_cthelper {
34 struct list_head list;
35 struct nf_conntrack_helper helper;
38 static LIST_HEAD(nfnl_cthelper_list);
41 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
42 struct nf_conn *ct, enum ip_conntrack_info ctinfo)
44 const struct nf_conn_help *help;
45 struct nf_conntrack_helper *helper;
51 /* rcu_read_lock()ed by nf_hook_thresh */
52 helper = rcu_dereference(help->helper);
56 /* This is a user-space helper not yet configured, skip. */
58 (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
59 NF_CT_HELPER_F_USERSPACE)
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;
66 static 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, },
72 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
73 const struct nlattr *attr)
76 struct nlattr *tb[NFCTH_TUPLE_MAX+1];
78 err = nla_parse_nested_deprecated(tb, NFCTH_TUPLE_MAX, attr,
79 nfnl_cthelper_tuple_pol, NULL);
83 if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
86 /* Not all fields are initialized so first zero the tuple */
87 memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
89 tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
90 tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
96 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
98 struct nf_conn_help *help = nfct_help(ct);
103 if (help->helper->data_len == 0)
106 nla_memcpy(help->data, attr, sizeof(help->data));
111 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
113 const struct nf_conn_help *help = nfct_help(ct);
115 if (help->helper->data_len &&
116 nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
117 goto nla_put_failure;
125 static 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, },
133 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
134 const struct nlattr *attr)
137 struct nlattr *tb[NFCTH_POLICY_MAX+1];
139 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
140 nfnl_cthelper_expect_pol, NULL);
144 if (!tb[NFCTH_POLICY_NAME] ||
145 !tb[NFCTH_POLICY_EXPECT_MAX] ||
146 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
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)
156 expect_policy->timeout =
157 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
162 static const struct nla_policy
163 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
164 [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
168 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
169 const struct nlattr *attr)
172 struct nf_conntrack_expect_policy *expect_policy;
173 struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
174 unsigned int class_max;
176 ret = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
177 nfnl_cthelper_expect_policy_set,
182 if (!tb[NFCTH_POLICY_SET_NUM])
185 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
188 if (class_max > NF_CT_MAX_EXPECT_CLASSES)
191 expect_policy = kcalloc(class_max,
192 sizeof(struct nf_conntrack_expect_policy),
194 if (expect_policy == NULL)
197 for (i = 0; i < class_max; i++) {
198 if (!tb[NFCTH_POLICY_SET+i])
201 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
202 tb[NFCTH_POLICY_SET+i]);
207 helper->expect_class_max = class_max - 1;
208 helper->expect_policy = expect_policy;
211 kfree(expect_policy);
216 nfnl_cthelper_create(const struct nlattr * const tb[],
217 struct nf_conntrack_tuple *tuple)
219 struct nf_conntrack_helper *helper;
220 struct nfnl_cthelper *nfcth;
224 if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
227 nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
230 helper = &nfcth->helper;
232 ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
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 > sizeof_field(struct nf_conn_help, data)) {
243 helper->data_len = size;
245 helper->flags |= NF_CT_HELPER_F_USERSPACE;
246 memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
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;
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]));
257 if (tb[NFCTH_STATUS]) {
258 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
261 case NFCT_HELPER_STATUS_ENABLED:
262 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
264 case NFCT_HELPER_STATUS_DISABLED:
265 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
270 ret = nf_conntrack_helper_register(helper);
274 list_add_tail(&nfcth->list, &nfnl_cthelper_list);
277 kfree(helper->expect_policy);
284 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
285 struct nf_conntrack_expect_policy *new_policy,
286 const struct nlattr *attr)
288 struct nlattr *tb[NFCTH_POLICY_MAX + 1];
291 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
292 nfnl_cthelper_expect_pol, NULL);
296 if (!tb[NFCTH_POLICY_NAME] ||
297 !tb[NFCTH_POLICY_EXPECT_MAX] ||
298 !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
301 if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
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)
309 new_policy->timeout =
310 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
315 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
316 struct nf_conntrack_helper *helper)
318 struct nf_conntrack_expect_policy *new_policy;
319 struct nf_conntrack_expect_policy *policy;
322 new_policy = kmalloc_array(helper->expect_class_max + 1,
323 sizeof(*new_policy), GFP_KERNEL);
327 /* Check first that all policy attributes are well-formed, so we don't
328 * leave things in inconsistent state on errors.
330 for (i = 0; i < helper->expect_class_max + 1; i++) {
332 if (!tb[NFCTH_POLICY_SET + i]) {
337 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
339 tb[NFCTH_POLICY_SET + i]);
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;
356 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
357 const struct nlattr *attr)
359 struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
360 unsigned int class_max;
363 err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
364 nfnl_cthelper_expect_policy_set,
369 if (!tb[NFCTH_POLICY_SET_NUM])
372 class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
373 if (helper->expect_class_max + 1 != class_max)
376 return nfnl_cthelper_update_policy_all(tb, helper);
380 nfnl_cthelper_update(const struct nlattr * const tb[],
381 struct nf_conntrack_helper *helper)
386 if (tb[NFCTH_PRIV_DATA_LEN]) {
387 size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
388 if (size != helper->data_len)
392 if (tb[NFCTH_POLICY]) {
393 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
397 if (tb[NFCTH_QUEUE_NUM])
398 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
400 if (tb[NFCTH_STATUS]) {
401 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
404 case NFCT_HELPER_STATUS_ENABLED:
405 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
407 case NFCT_HELPER_STATUS_DISABLED:
408 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
415 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
416 struct sk_buff *skb, const struct nlmsghdr *nlh,
417 const struct nlattr * const tb[],
418 struct netlink_ext_ack *extack)
420 const char *helper_name;
421 struct nf_conntrack_helper *cur, *helper = NULL;
422 struct nf_conntrack_tuple tuple;
423 struct nfnl_cthelper *nlcth;
426 if (!capable(CAP_NET_ADMIN))
429 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
432 helper_name = nla_data(tb[NFCTH_NAME]);
434 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
438 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
439 cur = &nlcth->helper;
441 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
444 if ((tuple.src.l3num != cur->tuple.src.l3num ||
445 tuple.dst.protonum != cur->tuple.dst.protonum))
448 if (nlh->nlmsg_flags & NLM_F_EXCL)
456 ret = nfnl_cthelper_create(tb, &tuple);
458 ret = nfnl_cthelper_update(tb, helper);
464 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
465 struct nf_conntrack_helper *helper)
467 struct nlattr *nest_parms;
469 nest_parms = nla_nest_start(skb, NFCTH_TUPLE);
470 if (nest_parms == NULL)
471 goto nla_put_failure;
473 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
474 htons(helper->tuple.src.l3num)))
475 goto nla_put_failure;
477 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
478 goto nla_put_failure;
480 nla_nest_end(skb, nest_parms);
488 nfnl_cthelper_dump_policy(struct sk_buff *skb,
489 struct nf_conntrack_helper *helper)
492 struct nlattr *nest_parms1, *nest_parms2;
494 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY);
495 if (nest_parms1 == NULL)
496 goto nla_put_failure;
498 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
499 htonl(helper->expect_class_max + 1)))
500 goto nla_put_failure;
502 for (i = 0; i < helper->expect_class_max + 1; i++) {
503 nest_parms2 = nla_nest_start(skb, (NFCTH_POLICY_SET + i));
504 if (nest_parms2 == NULL)
505 goto nla_put_failure;
507 if (nla_put_string(skb, NFCTH_POLICY_NAME,
508 helper->expect_policy[i].name))
509 goto nla_put_failure;
511 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
512 htonl(helper->expect_policy[i].max_expected)))
513 goto nla_put_failure;
515 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
516 htonl(helper->expect_policy[i].timeout)))
517 goto nla_put_failure;
519 nla_nest_end(skb, nest_parms2);
521 nla_nest_end(skb, nest_parms1);
529 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
530 int event, struct nf_conntrack_helper *helper)
532 struct nlmsghdr *nlh;
533 unsigned int flags = portid ? NLM_F_MULTI : 0;
536 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
537 nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
542 if (nla_put_string(skb, NFCTH_NAME, helper->name))
543 goto nla_put_failure;
545 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
546 goto nla_put_failure;
548 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
549 goto nla_put_failure;
551 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
552 goto nla_put_failure;
554 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
555 goto nla_put_failure;
557 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
558 status = NFCT_HELPER_STATUS_ENABLED;
560 status = NFCT_HELPER_STATUS_DISABLED;
562 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
563 goto nla_put_failure;
570 nlmsg_cancel(skb, nlh);
575 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
577 struct nf_conntrack_helper *cur, *last;
580 last = (struct nf_conntrack_helper *)cb->args[1];
581 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
583 hlist_for_each_entry_rcu(cur,
584 &nf_ct_helper_hash[cb->args[0]], hnode) {
586 /* skip non-userspace conntrack helpers. */
587 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
595 if (nfnl_cthelper_fill_info(skb,
596 NETLINK_CB(cb->skb).portid,
598 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
599 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
600 cb->args[1] = (unsigned long)cur;
614 static 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)
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;
627 if (!capable(CAP_NET_ADMIN))
630 if (nlh->nlmsg_flags & NLM_F_DUMP) {
631 struct netlink_dump_control c = {
632 .dump = nfnl_cthelper_dump_table,
634 return netlink_dump_start(nfnl, skb, nlh, &c);
638 helper_name = nla_data(tb[NFCTH_NAME]);
640 if (tb[NFCTH_TUPLE]) {
641 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
648 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
649 cur = &nlcth->helper;
651 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
655 (tuple.src.l3num != cur->tuple.src.l3num ||
656 tuple.dst.protonum != cur->tuple.dst.protonum))
659 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
665 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
667 NFNL_MSG_TYPE(nlh->nlmsg_type),
668 NFNL_MSG_CTHELPER_NEW, cur);
674 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
679 /* this avoids a loop in nfnetlink. */
680 return ret == -EAGAIN ? -ENOBUFS : ret;
685 static 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)
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;
697 if (!capable(CAP_NET_ADMIN))
701 helper_name = nla_data(tb[NFCTH_NAME]);
703 if (tb[NFCTH_TUPLE]) {
704 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
712 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
713 cur = &nlcth->helper;
717 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
721 (tuple.src.l3num != cur->tuple.src.l3num ||
722 tuple.dst.protonum != cur->tuple.dst.protonum))
725 if (refcount_dec_if_one(&cur->refcnt)) {
727 nf_conntrack_helper_unregister(cur);
728 kfree(cur->expect_policy);
730 list_del(&nlcth->list);
737 /* Make sure we return success if we flush and there is no helpers */
738 return (found || j == 0) ? 0 : ret;
741 static 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 [NFCTH_PRIV_DATA_LEN] = { .type = NLA_U32, },
746 [NFCTH_STATUS] = { .type = NLA_U32, },
749 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
750 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
751 .attr_count = NFCTH_MAX,
752 .policy = nfnl_cthelper_policy },
753 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
754 .attr_count = NFCTH_MAX,
755 .policy = nfnl_cthelper_policy },
756 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
757 .attr_count = NFCTH_MAX,
758 .policy = nfnl_cthelper_policy },
761 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
763 .subsys_id = NFNL_SUBSYS_CTHELPER,
764 .cb_count = NFNL_MSG_CTHELPER_MAX,
765 .cb = nfnl_cthelper_cb,
768 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
770 static int __init nfnl_cthelper_init(void)
774 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
776 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
784 static void __exit nfnl_cthelper_exit(void)
786 struct nf_conntrack_helper *cur;
787 struct nfnl_cthelper *nlcth, *n;
789 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
791 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
792 cur = &nlcth->helper;
794 nf_conntrack_helper_unregister(cur);
795 kfree(cur->expect_policy);
800 module_init(nfnl_cthelper_init);
801 module_exit(nfnl_cthelper_exit);