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_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)
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_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)) {
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)
385 if (tb[NFCTH_PRIV_DATA_LEN])
388 if (tb[NFCTH_POLICY]) {
389 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
393 if (tb[NFCTH_QUEUE_NUM])
394 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
396 if (tb[NFCTH_STATUS]) {
397 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
400 case NFCT_HELPER_STATUS_ENABLED:
401 helper->flags |= NF_CT_HELPER_F_CONFIGURED;
403 case NFCT_HELPER_STATUS_DISABLED:
404 helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
411 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
412 struct sk_buff *skb, const struct nlmsghdr *nlh,
413 const struct nlattr * const tb[],
414 struct netlink_ext_ack *extack)
416 const char *helper_name;
417 struct nf_conntrack_helper *cur, *helper = NULL;
418 struct nf_conntrack_tuple tuple;
419 struct nfnl_cthelper *nlcth;
422 if (!capable(CAP_NET_ADMIN))
425 if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
428 helper_name = nla_data(tb[NFCTH_NAME]);
430 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
434 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
435 cur = &nlcth->helper;
437 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
440 if ((tuple.src.l3num != cur->tuple.src.l3num ||
441 tuple.dst.protonum != cur->tuple.dst.protonum))
444 if (nlh->nlmsg_flags & NLM_F_EXCL)
452 ret = nfnl_cthelper_create(tb, &tuple);
454 ret = nfnl_cthelper_update(tb, helper);
460 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
461 struct nf_conntrack_helper *helper)
463 struct nlattr *nest_parms;
465 nest_parms = nla_nest_start(skb, NFCTH_TUPLE);
466 if (nest_parms == NULL)
467 goto nla_put_failure;
469 if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
470 htons(helper->tuple.src.l3num)))
471 goto nla_put_failure;
473 if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
474 goto nla_put_failure;
476 nla_nest_end(skb, nest_parms);
484 nfnl_cthelper_dump_policy(struct sk_buff *skb,
485 struct nf_conntrack_helper *helper)
488 struct nlattr *nest_parms1, *nest_parms2;
490 nest_parms1 = nla_nest_start(skb, NFCTH_POLICY);
491 if (nest_parms1 == NULL)
492 goto nla_put_failure;
494 if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
495 htonl(helper->expect_class_max + 1)))
496 goto nla_put_failure;
498 for (i = 0; i < helper->expect_class_max + 1; i++) {
499 nest_parms2 = nla_nest_start(skb, (NFCTH_POLICY_SET + i));
500 if (nest_parms2 == NULL)
501 goto nla_put_failure;
503 if (nla_put_string(skb, NFCTH_POLICY_NAME,
504 helper->expect_policy[i].name))
505 goto nla_put_failure;
507 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
508 htonl(helper->expect_policy[i].max_expected)))
509 goto nla_put_failure;
511 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
512 htonl(helper->expect_policy[i].timeout)))
513 goto nla_put_failure;
515 nla_nest_end(skb, nest_parms2);
517 nla_nest_end(skb, nest_parms1);
525 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
526 int event, struct nf_conntrack_helper *helper)
528 struct nlmsghdr *nlh;
529 struct nfgenmsg *nfmsg;
530 unsigned int flags = portid ? NLM_F_MULTI : 0;
533 event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
534 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
538 nfmsg = nlmsg_data(nlh);
539 nfmsg->nfgen_family = AF_UNSPEC;
540 nfmsg->version = NFNETLINK_V0;
543 if (nla_put_string(skb, NFCTH_NAME, helper->name))
544 goto nla_put_failure;
546 if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
547 goto nla_put_failure;
549 if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
550 goto nla_put_failure;
552 if (nfnl_cthelper_dump_policy(skb, helper) < 0)
553 goto nla_put_failure;
555 if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
556 goto nla_put_failure;
558 if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
559 status = NFCT_HELPER_STATUS_ENABLED;
561 status = NFCT_HELPER_STATUS_DISABLED;
563 if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
564 goto nla_put_failure;
571 nlmsg_cancel(skb, nlh);
576 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
578 struct nf_conntrack_helper *cur, *last;
581 last = (struct nf_conntrack_helper *)cb->args[1];
582 for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
584 hlist_for_each_entry_rcu(cur,
585 &nf_ct_helper_hash[cb->args[0]], hnode) {
587 /* skip non-userspace conntrack helpers. */
588 if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
596 if (nfnl_cthelper_fill_info(skb,
597 NETLINK_CB(cb->skb).portid,
599 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
600 NFNL_MSG_CTHELPER_NEW, cur) < 0) {
601 cb->args[1] = (unsigned long)cur;
615 static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
616 struct sk_buff *skb, const struct nlmsghdr *nlh,
617 const struct nlattr * const tb[],
618 struct netlink_ext_ack *extack)
621 struct nf_conntrack_helper *cur;
622 struct sk_buff *skb2;
623 char *helper_name = NULL;
624 struct nf_conntrack_tuple tuple;
625 struct nfnl_cthelper *nlcth;
626 bool tuple_set = false;
628 if (!capable(CAP_NET_ADMIN))
631 if (nlh->nlmsg_flags & NLM_F_DUMP) {
632 struct netlink_dump_control c = {
633 .dump = nfnl_cthelper_dump_table,
635 return netlink_dump_start(nfnl, skb, nlh, &c);
639 helper_name = nla_data(tb[NFCTH_NAME]);
641 if (tb[NFCTH_TUPLE]) {
642 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
649 list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
650 cur = &nlcth->helper;
652 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
656 (tuple.src.l3num != cur->tuple.src.l3num ||
657 tuple.dst.protonum != cur->tuple.dst.protonum))
660 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
666 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
668 NFNL_MSG_TYPE(nlh->nlmsg_type),
669 NFNL_MSG_CTHELPER_NEW, cur);
675 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
680 /* this avoids a loop in nfnetlink. */
681 return ret == -EAGAIN ? -ENOBUFS : ret;
686 static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
687 struct sk_buff *skb, const struct nlmsghdr *nlh,
688 const struct nlattr * const tb[],
689 struct netlink_ext_ack *extack)
691 char *helper_name = NULL;
692 struct nf_conntrack_helper *cur;
693 struct nf_conntrack_tuple tuple;
694 bool tuple_set = false, found = false;
695 struct nfnl_cthelper *nlcth, *n;
698 if (!capable(CAP_NET_ADMIN))
702 helper_name = nla_data(tb[NFCTH_NAME]);
704 if (tb[NFCTH_TUPLE]) {
705 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
713 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
714 cur = &nlcth->helper;
718 strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
722 (tuple.src.l3num != cur->tuple.src.l3num ||
723 tuple.dst.protonum != cur->tuple.dst.protonum))
726 if (refcount_dec_if_one(&cur->refcnt)) {
728 nf_conntrack_helper_unregister(cur);
729 kfree(cur->expect_policy);
731 list_del(&nlcth->list);
738 /* Make sure we return success if we flush and there is no helpers */
739 return (found || j == 0) ? 0 : ret;
742 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
743 [NFCTH_NAME] = { .type = NLA_NUL_STRING,
744 .len = NF_CT_HELPER_NAME_LEN-1 },
745 [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
746 [NFCTH_PRIV_DATA_LEN] = { .type = NLA_U32, },
747 [NFCTH_STATUS] = { .type = NLA_U32, },
750 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
751 [NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
752 .attr_count = NFCTH_MAX,
753 .policy = nfnl_cthelper_policy },
754 [NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
755 .attr_count = NFCTH_MAX,
756 .policy = nfnl_cthelper_policy },
757 [NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
758 .attr_count = NFCTH_MAX,
759 .policy = nfnl_cthelper_policy },
762 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
764 .subsys_id = NFNL_SUBSYS_CTHELPER,
765 .cb_count = NFNL_MSG_CTHELPER_MAX,
766 .cb = nfnl_cthelper_cb,
769 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
771 static int __init nfnl_cthelper_init(void)
775 ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
777 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
785 static void __exit nfnl_cthelper_exit(void)
787 struct nf_conntrack_helper *cur;
788 struct nfnl_cthelper *nlcth, *n;
790 nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
792 list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
793 cur = &nlcth->helper;
795 nf_conntrack_helper_unregister(cur);
796 kfree(cur->expect_policy);
801 module_init(nfnl_cthelper_init);
802 module_exit(nfnl_cthelper_exit);