1 /* Netfilter messages via netlink socket. Allows for user space
2 * protocol helpers and general trouble making from userspace.
4 * (C) 2001 by Jay Schulist <jschlst@samba.org>,
5 * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
6 * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
8 * Initial netfilter messages via netlink development funded and
9 * generally made possible by Network Robots, Inc. (www.networkrobots.com)
11 * Further development of this code funded by Astaro AG (http://www.astaro.com)
13 * This software may be used and distributed according to the terms
14 * of the GNU General Public License, incorporated herein by reference.
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/sockios.h>
23 #include <linux/net.h>
24 #include <linux/skbuff.h>
25 #include <linux/uaccess.h>
27 #include <linux/init.h>
28 #include <linux/sched/signal.h>
30 #include <net/netlink.h>
31 #include <linux/netfilter/nfnetlink.h>
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
35 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
36 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
38 #define nfnl_dereference_protected(id) \
39 rcu_dereference_protected(table[(id)].subsys, \
40 lockdep_nfnl_is_held((id)))
42 #define NFNL_MAX_ATTR_COUNT 32
46 const struct nfnetlink_subsystem __rcu *subsys;
47 } table[NFNL_SUBSYS_COUNT];
49 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
51 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
52 [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
53 [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
54 [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
55 [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
56 [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
57 [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
58 [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
59 [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
60 [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
61 [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
62 [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
63 [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
66 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
67 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
68 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
69 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
70 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
71 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
72 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
73 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
74 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
75 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
78 void nfnl_lock(__u8 subsys_id)
80 mutex_lock(&table[subsys_id].mutex);
82 EXPORT_SYMBOL_GPL(nfnl_lock);
84 void nfnl_unlock(__u8 subsys_id)
86 mutex_unlock(&table[subsys_id].mutex);
88 EXPORT_SYMBOL_GPL(nfnl_unlock);
90 #ifdef CONFIG_PROVE_LOCKING
91 bool lockdep_nfnl_is_held(u8 subsys_id)
93 return lockdep_is_held(&table[subsys_id].mutex);
95 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
98 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
102 /* Sanity-check attr_count size to avoid stack buffer overflow. */
103 for (cb_id = 0; cb_id < n->cb_count; cb_id++)
104 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
107 nfnl_lock(n->subsys_id);
108 if (table[n->subsys_id].subsys) {
109 nfnl_unlock(n->subsys_id);
112 rcu_assign_pointer(table[n->subsys_id].subsys, n);
113 nfnl_unlock(n->subsys_id);
117 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
119 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
121 nfnl_lock(n->subsys_id);
122 table[n->subsys_id].subsys = NULL;
123 nfnl_unlock(n->subsys_id);
127 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
129 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
131 u8 subsys_id = NFNL_SUBSYS_ID(type);
133 if (subsys_id >= NFNL_SUBSYS_COUNT)
136 return rcu_dereference(table[subsys_id].subsys);
139 static inline const struct nfnl_callback *
140 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
142 u8 cb_id = NFNL_MSG_TYPE(type);
144 if (cb_id >= ss->cb_count)
147 return &ss->cb[cb_id];
150 int nfnetlink_has_listeners(struct net *net, unsigned int group)
152 return netlink_has_listeners(net->nfnl, group);
154 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
156 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
157 unsigned int group, int echo, gfp_t flags)
159 return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
161 EXPORT_SYMBOL_GPL(nfnetlink_send);
163 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
165 return netlink_set_err(net->nfnl, portid, group, error);
167 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
169 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
173 err = nlmsg_unicast(net->nfnl, skb, portid);
179 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
181 /* Process one complete nfnetlink message. */
182 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
183 struct netlink_ext_ack *extack)
185 struct net *net = sock_net(skb->sk);
186 const struct nfnl_callback *nc;
187 const struct nfnetlink_subsystem *ss;
190 /* All the messages must at least contain nfgenmsg */
191 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
194 type = nlh->nlmsg_type;
197 ss = nfnetlink_get_subsys(type);
199 #ifdef CONFIG_MODULES
201 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
203 ss = nfnetlink_get_subsys(type);
212 nc = nfnetlink_find_client(type, ss);
219 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
220 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
221 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
222 struct nlattr *attr = (void *)nlh + min_len;
223 int attrlen = nlh->nlmsg_len - min_len;
224 __u8 subsys_id = NFNL_SUBSYS_ID(type);
226 /* Sanity-check NFNL_MAX_ATTR_COUNT */
227 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
232 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
234 ss->cb[cb_id].policy, extack);
241 err = nc->call_rcu(net, net->nfnl, skb, nlh,
242 (const struct nlattr **)cda,
247 nfnl_lock(subsys_id);
248 if (nfnl_dereference_protected(subsys_id) != ss ||
249 nfnetlink_find_client(type, ss) != nc)
252 err = nc->call(net, net->nfnl, skb, nlh,
253 (const struct nlattr **)cda,
257 nfnl_unlock(subsys_id);
266 struct list_head head;
267 struct nlmsghdr *nlh;
269 struct netlink_ext_ack extack;
272 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
273 const struct netlink_ext_ack *extack)
275 struct nfnl_err *nfnl_err;
277 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
278 if (nfnl_err == NULL)
283 nfnl_err->extack = *extack;
284 list_add_tail(&nfnl_err->head, list);
289 static void nfnl_err_del(struct nfnl_err *nfnl_err)
291 list_del(&nfnl_err->head);
295 static void nfnl_err_reset(struct list_head *err_list)
297 struct nfnl_err *nfnl_err, *next;
299 list_for_each_entry_safe(nfnl_err, next, err_list, head)
300 nfnl_err_del(nfnl_err);
303 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
305 struct nfnl_err *nfnl_err, *next;
307 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
308 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
310 nfnl_err_del(nfnl_err);
315 NFNL_BATCH_FAILURE = (1 << 0),
316 NFNL_BATCH_DONE = (1 << 1),
317 NFNL_BATCH_REPLAY = (1 << 2),
320 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
321 u16 subsys_id, u32 genid)
323 struct sk_buff *oskb = skb;
324 struct net *net = sock_net(skb->sk);
325 const struct nfnetlink_subsystem *ss;
326 const struct nfnl_callback *nc;
327 struct netlink_ext_ack extack;
332 if (subsys_id >= NFNL_SUBSYS_COUNT)
333 return netlink_ack(skb, nlh, -EINVAL, NULL);
337 skb = netlink_skb_clone(oskb, GFP_KERNEL);
339 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
341 nfnl_lock(subsys_id);
342 ss = nfnl_dereference_protected(subsys_id);
344 #ifdef CONFIG_MODULES
345 nfnl_unlock(subsys_id);
346 request_module("nfnetlink-subsys-%d", subsys_id);
347 nfnl_lock(subsys_id);
348 ss = nfnl_dereference_protected(subsys_id);
352 nfnl_unlock(subsys_id);
353 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
354 return kfree_skb(skb);
358 if (!ss->valid_genid || !ss->commit || !ss->abort) {
359 nfnl_unlock(subsys_id);
360 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
361 return kfree_skb(skb);
364 if (!try_module_get(ss->owner)) {
365 nfnl_unlock(subsys_id);
366 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
367 return kfree_skb(skb);
370 if (!ss->valid_genid(net, genid)) {
371 module_put(ss->owner);
372 nfnl_unlock(subsys_id);
373 netlink_ack(oskb, nlh, -ERESTART, NULL);
374 return kfree_skb(skb);
377 nfnl_unlock(subsys_id);
379 while (skb->len >= nlmsg_total_size(0)) {
382 if (fatal_signal_pending(current)) {
383 nfnl_err_reset(&err_list);
385 status = NFNL_BATCH_FAILURE;
389 memset(&extack, 0, sizeof(extack));
390 nlh = nlmsg_hdr(skb);
393 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
394 skb->len < nlh->nlmsg_len ||
395 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
396 nfnl_err_reset(&err_list);
397 status |= NFNL_BATCH_FAILURE;
401 /* Only requests are handled by the kernel */
402 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
407 type = nlh->nlmsg_type;
408 if (type == NFNL_MSG_BATCH_BEGIN) {
409 /* Malformed: Batch begin twice */
410 nfnl_err_reset(&err_list);
411 status |= NFNL_BATCH_FAILURE;
413 } else if (type == NFNL_MSG_BATCH_END) {
414 status |= NFNL_BATCH_DONE;
416 } else if (type < NLMSG_MIN_TYPE) {
421 /* We only accept a batch with messages for the same
424 if (NFNL_SUBSYS_ID(type) != subsys_id) {
429 nc = nfnetlink_find_client(type, ss);
436 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
437 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
438 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
439 struct nlattr *attr = (void *)nlh + min_len;
440 int attrlen = nlh->nlmsg_len - min_len;
442 /* Sanity-check NFTA_MAX_ATTR */
443 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
448 err = nla_parse_deprecated(cda,
449 ss->cb[cb_id].attr_count,
451 ss->cb[cb_id].policy, NULL);
455 if (nc->call_batch) {
456 err = nc->call_batch(net, net->nfnl, skb, nlh,
457 (const struct nlattr **)cda,
461 /* The lock was released to autoload some module, we
462 * have to abort and start from scratch using the
465 if (err == -EAGAIN) {
466 status |= NFNL_BATCH_REPLAY;
471 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
472 /* Errors are delivered once the full batch has been
473 * processed, this avoids that the same error is
474 * reported several times when replaying the batch.
476 if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
477 /* We failed to enqueue an error, reset the
478 * list of errors and send OOM to userspace
479 * pointing to the batch header.
481 nfnl_err_reset(&err_list);
482 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
484 status |= NFNL_BATCH_FAILURE;
487 /* We don't stop processing the batch on errors, thus,
488 * userspace gets all the errors that the batch
492 status |= NFNL_BATCH_FAILURE;
495 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
496 if (msglen > skb->len)
498 skb_pull(skb, msglen);
501 if (status & NFNL_BATCH_REPLAY) {
502 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
503 nfnl_err_reset(&err_list);
505 module_put(ss->owner);
507 } else if (status == NFNL_BATCH_DONE) {
508 err = ss->commit(net, oskb);
509 if (err == -EAGAIN) {
510 status |= NFNL_BATCH_REPLAY;
513 ss->abort(net, oskb, NFNL_ABORT_NONE);
514 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
517 enum nfnl_abort_action abort_action;
519 if (status & NFNL_BATCH_FAILURE)
520 abort_action = NFNL_ABORT_NONE;
522 abort_action = NFNL_ABORT_VALIDATE;
524 err = ss->abort(net, oskb, abort_action);
525 if (err == -EAGAIN) {
526 nfnl_err_reset(&err_list);
528 module_put(ss->owner);
529 status |= NFNL_BATCH_FAILURE;
536 nfnl_err_deliver(&err_list, oskb);
538 module_put(ss->owner);
541 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
542 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
545 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
547 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
548 struct nlattr *attr = (void *)nlh + min_len;
549 struct nlattr *cda[NFNL_BATCH_MAX + 1];
550 int attrlen = nlh->nlmsg_len - min_len;
551 struct nfgenmsg *nfgenmsg;
556 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
557 if (msglen > skb->len)
560 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
563 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
564 nfnl_batch_policy, NULL);
566 netlink_ack(skb, nlh, err, NULL);
569 if (cda[NFNL_BATCH_GENID])
570 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
572 nfgenmsg = nlmsg_data(nlh);
573 skb_pull(skb, msglen);
574 /* Work around old nft using host byte order */
575 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
576 res_id = NFNL_SUBSYS_NFTABLES;
578 res_id = ntohs(nfgenmsg->res_id);
580 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
583 static void nfnetlink_rcv(struct sk_buff *skb)
585 struct nlmsghdr *nlh = nlmsg_hdr(skb);
587 if (skb->len < NLMSG_HDRLEN ||
588 nlh->nlmsg_len < NLMSG_HDRLEN ||
589 skb->len < nlh->nlmsg_len)
592 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
593 netlink_ack(skb, nlh, -EPERM, NULL);
597 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
598 nfnetlink_rcv_skb_batch(skb, nlh);
600 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
603 #ifdef CONFIG_MODULES
604 static int nfnetlink_bind(struct net *net, int group)
606 const struct nfnetlink_subsystem *ss;
609 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
612 type = nfnl_group2type[group];
615 ss = nfnetlink_get_subsys(type << 8);
618 request_module_nowait("nfnetlink-subsys-%d", type);
623 static int __net_init nfnetlink_net_init(struct net *net)
626 struct netlink_kernel_cfg cfg = {
627 .groups = NFNLGRP_MAX,
628 .input = nfnetlink_rcv,
629 #ifdef CONFIG_MODULES
630 .bind = nfnetlink_bind,
634 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
637 net->nfnl_stash = nfnl;
638 rcu_assign_pointer(net->nfnl, nfnl);
642 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
646 list_for_each_entry(net, net_exit_list, exit_list)
647 RCU_INIT_POINTER(net->nfnl, NULL);
649 list_for_each_entry(net, net_exit_list, exit_list)
650 netlink_kernel_release(net->nfnl_stash);
653 static struct pernet_operations nfnetlink_net_ops = {
654 .init = nfnetlink_net_init,
655 .exit_batch = nfnetlink_net_exit_batch,
658 static int __init nfnetlink_init(void)
662 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
663 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
665 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
666 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
668 return register_pernet_subsys(&nfnetlink_net_ops);
671 static void __exit nfnetlink_exit(void)
673 unregister_pernet_subsys(&nfnetlink_net_ops);
675 module_init(nfnetlink_init);
676 module_exit(nfnetlink_exit);