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 <net/netns/generic.h>
32 #include <linux/netfilter/nfnetlink.h>
34 MODULE_LICENSE("GPL");
35 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
36 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
37 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
39 #define nfnl_dereference_protected(id) \
40 rcu_dereference_protected(table[(id)].subsys, \
41 lockdep_nfnl_is_held((id)))
43 #define NFNL_MAX_ATTR_COUNT 32
45 static unsigned int nfnetlink_pernet_id __read_mostly;
53 const struct nfnetlink_subsystem __rcu *subsys;
54 } table[NFNL_SUBSYS_COUNT];
56 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
58 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
59 [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
60 [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
61 [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
62 [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
63 [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
64 [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
65 [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
66 [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
67 [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
68 [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
69 [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
70 [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
71 [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook",
74 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
75 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
76 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
77 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
78 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
79 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
80 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
81 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
82 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
83 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
86 static struct nfnl_net *nfnl_pernet(struct net *net)
88 return net_generic(net, nfnetlink_pernet_id);
91 void nfnl_lock(__u8 subsys_id)
93 mutex_lock(&table[subsys_id].mutex);
95 EXPORT_SYMBOL_GPL(nfnl_lock);
97 void nfnl_unlock(__u8 subsys_id)
99 mutex_unlock(&table[subsys_id].mutex);
101 EXPORT_SYMBOL_GPL(nfnl_unlock);
103 #ifdef CONFIG_PROVE_LOCKING
104 bool lockdep_nfnl_is_held(u8 subsys_id)
106 return lockdep_is_held(&table[subsys_id].mutex);
108 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
111 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
115 /* Sanity-check attr_count size to avoid stack buffer overflow. */
116 for (cb_id = 0; cb_id < n->cb_count; cb_id++)
117 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
120 nfnl_lock(n->subsys_id);
121 if (table[n->subsys_id].subsys) {
122 nfnl_unlock(n->subsys_id);
125 rcu_assign_pointer(table[n->subsys_id].subsys, n);
126 nfnl_unlock(n->subsys_id);
130 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
132 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
134 nfnl_lock(n->subsys_id);
135 table[n->subsys_id].subsys = NULL;
136 nfnl_unlock(n->subsys_id);
140 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
142 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
144 u8 subsys_id = NFNL_SUBSYS_ID(type);
146 if (subsys_id >= NFNL_SUBSYS_COUNT)
149 return rcu_dereference(table[subsys_id].subsys);
152 static inline const struct nfnl_callback *
153 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
155 u8 cb_id = NFNL_MSG_TYPE(type);
157 if (cb_id >= ss->cb_count)
160 return &ss->cb[cb_id];
163 int nfnetlink_has_listeners(struct net *net, unsigned int group)
165 struct nfnl_net *nfnlnet = nfnl_pernet(net);
167 return netlink_has_listeners(nfnlnet->nfnl, group);
169 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
171 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
172 unsigned int group, int echo, gfp_t flags)
174 struct nfnl_net *nfnlnet = nfnl_pernet(net);
176 return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags);
178 EXPORT_SYMBOL_GPL(nfnetlink_send);
180 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
182 struct nfnl_net *nfnlnet = nfnl_pernet(net);
184 return netlink_set_err(nfnlnet->nfnl, portid, group, error);
186 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
188 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
190 struct nfnl_net *nfnlnet = nfnl_pernet(net);
193 err = nlmsg_unicast(nfnlnet->nfnl, skb, portid);
199 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
201 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
202 __u32 group, gfp_t allocation)
204 struct nfnl_net *nfnlnet = nfnl_pernet(net);
206 netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation);
208 EXPORT_SYMBOL_GPL(nfnetlink_broadcast);
210 /* Process one complete nfnetlink message. */
211 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
212 struct netlink_ext_ack *extack)
214 struct net *net = sock_net(skb->sk);
215 const struct nfnl_callback *nc;
216 const struct nfnetlink_subsystem *ss;
219 /* All the messages must at least contain nfgenmsg */
220 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
223 type = nlh->nlmsg_type;
227 ss = nfnetlink_get_subsys(type);
229 #ifdef CONFIG_MODULES
231 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
233 ss = nfnetlink_get_subsys(type);
242 nc = nfnetlink_find_client(type, ss);
249 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
250 struct nfnl_net *nfnlnet = nfnl_pernet(net);
251 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
252 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
253 struct nlattr *attr = (void *)nlh + min_len;
254 int attrlen = nlh->nlmsg_len - min_len;
255 __u8 subsys_id = NFNL_SUBSYS_ID(type);
256 struct nfnl_info info = {
260 .nfmsg = nlmsg_data(nlh),
264 /* Sanity-check NFNL_MAX_ATTR_COUNT */
265 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
270 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
272 ss->cb[cb_id].policy, extack);
285 err = nc->call(skb, &info, (const struct nlattr **)cda);
290 nfnl_lock(subsys_id);
291 if (nfnl_dereference_protected(subsys_id) != ss ||
292 nfnetlink_find_client(type, ss) != nc) {
296 err = nc->call(skb, &info, (const struct nlattr **)cda);
297 nfnl_unlock(subsys_id);
311 struct list_head head;
312 struct nlmsghdr *nlh;
314 struct netlink_ext_ack extack;
317 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
318 const struct netlink_ext_ack *extack)
320 struct nfnl_err *nfnl_err;
322 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
323 if (nfnl_err == NULL)
328 nfnl_err->extack = *extack;
329 list_add_tail(&nfnl_err->head, list);
334 static void nfnl_err_del(struct nfnl_err *nfnl_err)
336 list_del(&nfnl_err->head);
340 static void nfnl_err_reset(struct list_head *err_list)
342 struct nfnl_err *nfnl_err, *next;
344 list_for_each_entry_safe(nfnl_err, next, err_list, head)
345 nfnl_err_del(nfnl_err);
348 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
350 struct nfnl_err *nfnl_err, *next;
352 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
353 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
355 nfnl_err_del(nfnl_err);
360 NFNL_BATCH_FAILURE = (1 << 0),
361 NFNL_BATCH_DONE = (1 << 1),
362 NFNL_BATCH_REPLAY = (1 << 2),
365 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
366 u16 subsys_id, u32 genid)
368 struct sk_buff *oskb = skb;
369 struct net *net = sock_net(skb->sk);
370 const struct nfnetlink_subsystem *ss;
371 const struct nfnl_callback *nc;
372 struct netlink_ext_ack extack;
377 if (subsys_id >= NFNL_SUBSYS_COUNT)
378 return netlink_ack(skb, nlh, -EINVAL, NULL);
382 skb = netlink_skb_clone(oskb, GFP_KERNEL);
384 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
386 nfnl_lock(subsys_id);
387 ss = nfnl_dereference_protected(subsys_id);
389 #ifdef CONFIG_MODULES
390 nfnl_unlock(subsys_id);
391 request_module("nfnetlink-subsys-%d", subsys_id);
392 nfnl_lock(subsys_id);
393 ss = nfnl_dereference_protected(subsys_id);
397 nfnl_unlock(subsys_id);
398 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
399 return kfree_skb(skb);
403 if (!ss->valid_genid || !ss->commit || !ss->abort) {
404 nfnl_unlock(subsys_id);
405 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
406 return kfree_skb(skb);
409 if (!try_module_get(ss->owner)) {
410 nfnl_unlock(subsys_id);
411 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
412 return kfree_skb(skb);
415 if (!ss->valid_genid(net, genid)) {
416 module_put(ss->owner);
417 nfnl_unlock(subsys_id);
418 netlink_ack(oskb, nlh, -ERESTART, NULL);
419 return kfree_skb(skb);
422 nfnl_unlock(subsys_id);
424 while (skb->len >= nlmsg_total_size(0)) {
427 if (fatal_signal_pending(current)) {
428 nfnl_err_reset(&err_list);
430 status = NFNL_BATCH_FAILURE;
434 memset(&extack, 0, sizeof(extack));
435 nlh = nlmsg_hdr(skb);
438 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
439 skb->len < nlh->nlmsg_len ||
440 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
441 nfnl_err_reset(&err_list);
442 status |= NFNL_BATCH_FAILURE;
446 /* Only requests are handled by the kernel */
447 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
452 type = nlh->nlmsg_type;
453 if (type == NFNL_MSG_BATCH_BEGIN) {
454 /* Malformed: Batch begin twice */
455 nfnl_err_reset(&err_list);
456 status |= NFNL_BATCH_FAILURE;
458 } else if (type == NFNL_MSG_BATCH_END) {
459 status |= NFNL_BATCH_DONE;
461 } else if (type < NLMSG_MIN_TYPE) {
466 /* We only accept a batch with messages for the same
469 if (NFNL_SUBSYS_ID(type) != subsys_id) {
474 nc = nfnetlink_find_client(type, ss);
480 if (nc->type != NFNL_CB_BATCH) {
486 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
487 struct nfnl_net *nfnlnet = nfnl_pernet(net);
488 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
489 struct nlattr *attr = (void *)nlh + min_len;
490 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
491 int attrlen = nlh->nlmsg_len - min_len;
492 struct nfnl_info info = {
496 .nfmsg = nlmsg_data(nlh),
500 /* Sanity-check NFTA_MAX_ATTR */
501 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
506 err = nla_parse_deprecated(cda,
507 ss->cb[cb_id].attr_count,
509 ss->cb[cb_id].policy, NULL);
513 err = nc->call(skb, &info, (const struct nlattr **)cda);
515 /* The lock was released to autoload some module, we
516 * have to abort and start from scratch using the
519 if (err == -EAGAIN) {
520 status |= NFNL_BATCH_REPLAY;
525 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
526 /* Errors are delivered once the full batch has been
527 * processed, this avoids that the same error is
528 * reported several times when replaying the batch.
530 if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
531 /* We failed to enqueue an error, reset the
532 * list of errors and send OOM to userspace
533 * pointing to the batch header.
535 nfnl_err_reset(&err_list);
536 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
538 status |= NFNL_BATCH_FAILURE;
541 /* We don't stop processing the batch on errors, thus,
542 * userspace gets all the errors that the batch
546 status |= NFNL_BATCH_FAILURE;
549 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
550 if (msglen > skb->len)
552 skb_pull(skb, msglen);
555 if (status & NFNL_BATCH_REPLAY) {
556 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
557 nfnl_err_reset(&err_list);
559 module_put(ss->owner);
561 } else if (status == NFNL_BATCH_DONE) {
562 err = ss->commit(net, oskb);
563 if (err == -EAGAIN) {
564 status |= NFNL_BATCH_REPLAY;
567 ss->abort(net, oskb, NFNL_ABORT_NONE);
568 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
571 enum nfnl_abort_action abort_action;
573 if (status & NFNL_BATCH_FAILURE)
574 abort_action = NFNL_ABORT_NONE;
576 abort_action = NFNL_ABORT_VALIDATE;
578 err = ss->abort(net, oskb, abort_action);
579 if (err == -EAGAIN) {
580 nfnl_err_reset(&err_list);
582 module_put(ss->owner);
583 status |= NFNL_BATCH_FAILURE;
590 nfnl_err_deliver(&err_list, oskb);
592 module_put(ss->owner);
595 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
596 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
599 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
601 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
602 struct nlattr *attr = (void *)nlh + min_len;
603 struct nlattr *cda[NFNL_BATCH_MAX + 1];
604 int attrlen = nlh->nlmsg_len - min_len;
605 struct nfgenmsg *nfgenmsg;
610 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
611 if (msglen > skb->len)
614 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
617 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
618 nfnl_batch_policy, NULL);
620 netlink_ack(skb, nlh, err, NULL);
623 if (cda[NFNL_BATCH_GENID])
624 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
626 nfgenmsg = nlmsg_data(nlh);
627 skb_pull(skb, msglen);
628 /* Work around old nft using host byte order */
629 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
630 res_id = NFNL_SUBSYS_NFTABLES;
632 res_id = ntohs(nfgenmsg->res_id);
634 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
637 static void nfnetlink_rcv(struct sk_buff *skb)
639 struct nlmsghdr *nlh = nlmsg_hdr(skb);
641 if (skb->len < NLMSG_HDRLEN ||
642 nlh->nlmsg_len < NLMSG_HDRLEN ||
643 skb->len < nlh->nlmsg_len)
646 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
647 netlink_ack(skb, nlh, -EPERM, NULL);
651 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
652 nfnetlink_rcv_skb_batch(skb, nlh);
654 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
657 #ifdef CONFIG_MODULES
658 static int nfnetlink_bind(struct net *net, int group)
660 const struct nfnetlink_subsystem *ss;
663 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
666 type = nfnl_group2type[group];
669 ss = nfnetlink_get_subsys(type << 8);
672 request_module_nowait("nfnetlink-subsys-%d", type);
677 static int __net_init nfnetlink_net_init(struct net *net)
679 struct nfnl_net *nfnlnet = nfnl_pernet(net);
680 struct netlink_kernel_cfg cfg = {
681 .groups = NFNLGRP_MAX,
682 .input = nfnetlink_rcv,
683 #ifdef CONFIG_MODULES
684 .bind = nfnetlink_bind,
688 nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
694 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
696 struct nfnl_net *nfnlnet;
699 list_for_each_entry(net, net_exit_list, exit_list) {
700 nfnlnet = nfnl_pernet(net);
702 netlink_kernel_release(nfnlnet->nfnl);
706 static struct pernet_operations nfnetlink_net_ops = {
707 .init = nfnetlink_net_init,
708 .exit_batch = nfnetlink_net_exit_batch,
709 .id = &nfnetlink_pernet_id,
710 .size = sizeof(struct nfnl_net),
713 static int __init nfnetlink_init(void)
717 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
718 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
720 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
721 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
723 return register_pernet_subsys(&nfnetlink_net_ops);
726 static void __exit nfnetlink_exit(void)
728 unregister_pernet_subsys(&nfnetlink_net_ops);
730 module_init(nfnetlink_init);
731 module_exit(nfnetlink_exit);