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TOMOYO Linux Cross Reference
Linux/net/netfilter/nfnetlink.c

Version: ~ [ linux-6.11.5 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.58 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.114 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.169 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.228 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.284 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.322 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* Netfilter messages via netlink socket. Allows for user space
  2  * protocol helpers and general trouble making from userspace.
  3  *
  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>
  7  *
  8  * Initial netfilter messages via netlink development funded and
  9  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
 10  *
 11  * Further development of this code funded by Astaro AG (http://www.astaro.com)
 12  *
 13  * This software may be used and distributed according to the terms
 14  * of the GNU General Public License, incorporated herein by reference.
 15  */
 16 
 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>
 26 #include <net/sock.h>
 27 #include <linux/init.h>
 28 #include <linux/sched/signal.h>
 29 
 30 #include <net/netlink.h>
 31 #include <net/netns/generic.h>
 32 #include <linux/netfilter.h>
 33 #include <linux/netfilter/nfnetlink.h>
 34 
 35 MODULE_LICENSE("GPL");
 36 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
 37 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
 38 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
 39 
 40 #define nfnl_dereference_protected(id) \
 41         rcu_dereference_protected(table[(id)].subsys, \
 42                                   lockdep_nfnl_is_held((id)))
 43 
 44 #define NFNL_MAX_ATTR_COUNT     32
 45 
 46 static unsigned int nfnetlink_pernet_id __read_mostly;
 47 
 48 #ifdef CONFIG_NF_CONNTRACK_EVENTS
 49 static DEFINE_SPINLOCK(nfnl_grp_active_lock);
 50 #endif
 51 
 52 struct nfnl_net {
 53         struct sock *nfnl;
 54 };
 55 
 56 static struct {
 57         struct mutex                            mutex;
 58         const struct nfnetlink_subsystem __rcu  *subsys;
 59 } table[NFNL_SUBSYS_COUNT];
 60 
 61 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
 62 
 63 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
 64         [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
 65         [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
 66         [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
 67         [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
 68         [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
 69         [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
 70         [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
 71         [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
 72         [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
 73         [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
 74         [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
 75         [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
 76         [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook",
 77 };
 78 
 79 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
 80         [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
 81         [NFNLGRP_CONNTRACK_UPDATE]      = NFNL_SUBSYS_CTNETLINK,
 82         [NFNLGRP_CONNTRACK_DESTROY]     = NFNL_SUBSYS_CTNETLINK,
 83         [NFNLGRP_CONNTRACK_EXP_NEW]     = NFNL_SUBSYS_CTNETLINK_EXP,
 84         [NFNLGRP_CONNTRACK_EXP_UPDATE]  = NFNL_SUBSYS_CTNETLINK_EXP,
 85         [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
 86         [NFNLGRP_NFTABLES]              = NFNL_SUBSYS_NFTABLES,
 87         [NFNLGRP_ACCT_QUOTA]            = NFNL_SUBSYS_ACCT,
 88         [NFNLGRP_NFTRACE]               = NFNL_SUBSYS_NFTABLES,
 89 };
 90 
 91 static struct nfnl_net *nfnl_pernet(struct net *net)
 92 {
 93         return net_generic(net, nfnetlink_pernet_id);
 94 }
 95 
 96 void nfnl_lock(__u8 subsys_id)
 97 {
 98         mutex_lock(&table[subsys_id].mutex);
 99 }
100 EXPORT_SYMBOL_GPL(nfnl_lock);
101 
102 void nfnl_unlock(__u8 subsys_id)
103 {
104         mutex_unlock(&table[subsys_id].mutex);
105 }
106 EXPORT_SYMBOL_GPL(nfnl_unlock);
107 
108 #ifdef CONFIG_PROVE_LOCKING
109 bool lockdep_nfnl_is_held(u8 subsys_id)
110 {
111         return lockdep_is_held(&table[subsys_id].mutex);
112 }
113 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
114 #endif
115 
116 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
117 {
118         u8 cb_id;
119 
120         /* Sanity-check attr_count size to avoid stack buffer overflow. */
121         for (cb_id = 0; cb_id < n->cb_count; cb_id++)
122                 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
123                         return -EINVAL;
124 
125         nfnl_lock(n->subsys_id);
126         if (table[n->subsys_id].subsys) {
127                 nfnl_unlock(n->subsys_id);
128                 return -EBUSY;
129         }
130         rcu_assign_pointer(table[n->subsys_id].subsys, n);
131         nfnl_unlock(n->subsys_id);
132 
133         return 0;
134 }
135 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
136 
137 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
138 {
139         nfnl_lock(n->subsys_id);
140         table[n->subsys_id].subsys = NULL;
141         nfnl_unlock(n->subsys_id);
142         synchronize_rcu();
143         return 0;
144 }
145 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
146 
147 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
148 {
149         u8 subsys_id = NFNL_SUBSYS_ID(type);
150 
151         if (subsys_id >= NFNL_SUBSYS_COUNT)
152                 return NULL;
153 
154         return rcu_dereference(table[subsys_id].subsys);
155 }
156 
157 static inline const struct nfnl_callback *
158 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
159 {
160         u8 cb_id = NFNL_MSG_TYPE(type);
161 
162         if (cb_id >= ss->cb_count)
163                 return NULL;
164 
165         return &ss->cb[cb_id];
166 }
167 
168 int nfnetlink_has_listeners(struct net *net, unsigned int group)
169 {
170         struct nfnl_net *nfnlnet = nfnl_pernet(net);
171 
172         return netlink_has_listeners(nfnlnet->nfnl, group);
173 }
174 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
175 
176 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
177                    unsigned int group, int echo, gfp_t flags)
178 {
179         struct nfnl_net *nfnlnet = nfnl_pernet(net);
180 
181         return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags);
182 }
183 EXPORT_SYMBOL_GPL(nfnetlink_send);
184 
185 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
186 {
187         struct nfnl_net *nfnlnet = nfnl_pernet(net);
188 
189         return netlink_set_err(nfnlnet->nfnl, portid, group, error);
190 }
191 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
192 
193 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
194 {
195         struct nfnl_net *nfnlnet = nfnl_pernet(net);
196         int err;
197 
198         err = nlmsg_unicast(nfnlnet->nfnl, skb, portid);
199         if (err == -EAGAIN)
200                 err = -ENOBUFS;
201 
202         return err;
203 }
204 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
205 
206 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
207                          __u32 group, gfp_t allocation)
208 {
209         struct nfnl_net *nfnlnet = nfnl_pernet(net);
210 
211         netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation);
212 }
213 EXPORT_SYMBOL_GPL(nfnetlink_broadcast);
214 
215 /* Process one complete nfnetlink message. */
216 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
217                              struct netlink_ext_ack *extack)
218 {
219         struct net *net = sock_net(skb->sk);
220         const struct nfnl_callback *nc;
221         const struct nfnetlink_subsystem *ss;
222         int type, err;
223 
224         /* All the messages must at least contain nfgenmsg */
225         if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
226                 return 0;
227 
228         type = nlh->nlmsg_type;
229 replay:
230         rcu_read_lock();
231 
232         ss = nfnetlink_get_subsys(type);
233         if (!ss) {
234 #ifdef CONFIG_MODULES
235                 rcu_read_unlock();
236                 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
237                 rcu_read_lock();
238                 ss = nfnetlink_get_subsys(type);
239                 if (!ss)
240 #endif
241                 {
242                         rcu_read_unlock();
243                         return -EINVAL;
244                 }
245         }
246 
247         nc = nfnetlink_find_client(type, ss);
248         if (!nc) {
249                 rcu_read_unlock();
250                 return -EINVAL;
251         }
252 
253         {
254                 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
255                 struct nfnl_net *nfnlnet = nfnl_pernet(net);
256                 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
257                 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
258                 struct nlattr *attr = (void *)nlh + min_len;
259                 int attrlen = nlh->nlmsg_len - min_len;
260                 __u8 subsys_id = NFNL_SUBSYS_ID(type);
261                 struct nfnl_info info = {
262                         .net    = net,
263                         .sk     = nfnlnet->nfnl,
264                         .nlh    = nlh,
265                         .nfmsg  = nlmsg_data(nlh),
266                         .extack = extack,
267                 };
268 
269                 /* Sanity-check NFNL_MAX_ATTR_COUNT */
270                 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
271                         rcu_read_unlock();
272                         return -ENOMEM;
273                 }
274 
275                 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
276                                            attr, attrlen,
277                                            ss->cb[cb_id].policy, extack);
278                 if (err < 0) {
279                         rcu_read_unlock();
280                         return err;
281                 }
282 
283                 if (!nc->call) {
284                         rcu_read_unlock();
285                         return -EINVAL;
286                 }
287 
288                 switch (nc->type) {
289                 case NFNL_CB_RCU:
290                         err = nc->call(skb, &info, (const struct nlattr **)cda);
291                         rcu_read_unlock();
292                         break;
293                 case NFNL_CB_MUTEX:
294                         rcu_read_unlock();
295                         nfnl_lock(subsys_id);
296                         if (nfnl_dereference_protected(subsys_id) != ss ||
297                             nfnetlink_find_client(type, ss) != nc) {
298                                 nfnl_unlock(subsys_id);
299                                 err = -EAGAIN;
300                                 break;
301                         }
302                         err = nc->call(skb, &info, (const struct nlattr **)cda);
303                         nfnl_unlock(subsys_id);
304                         break;
305                 default:
306                         rcu_read_unlock();
307                         err = -EINVAL;
308                         break;
309                 }
310                 if (err == -EAGAIN)
311                         goto replay;
312                 return err;
313         }
314 }
315 
316 struct nfnl_err {
317         struct list_head        head;
318         struct nlmsghdr         *nlh;
319         int                     err;
320         struct netlink_ext_ack  extack;
321 };
322 
323 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
324                         const struct netlink_ext_ack *extack)
325 {
326         struct nfnl_err *nfnl_err;
327 
328         nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
329         if (nfnl_err == NULL)
330                 return -ENOMEM;
331 
332         nfnl_err->nlh = nlh;
333         nfnl_err->err = err;
334         nfnl_err->extack = *extack;
335         list_add_tail(&nfnl_err->head, list);
336 
337         return 0;
338 }
339 
340 static void nfnl_err_del(struct nfnl_err *nfnl_err)
341 {
342         list_del(&nfnl_err->head);
343         kfree(nfnl_err);
344 }
345 
346 static void nfnl_err_reset(struct list_head *err_list)
347 {
348         struct nfnl_err *nfnl_err, *next;
349 
350         list_for_each_entry_safe(nfnl_err, next, err_list, head)
351                 nfnl_err_del(nfnl_err);
352 }
353 
354 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
355 {
356         struct nfnl_err *nfnl_err, *next;
357 
358         list_for_each_entry_safe(nfnl_err, next, err_list, head) {
359                 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
360                             &nfnl_err->extack);
361                 nfnl_err_del(nfnl_err);
362         }
363 }
364 
365 enum {
366         NFNL_BATCH_FAILURE      = (1 << 0),
367         NFNL_BATCH_DONE         = (1 << 1),
368         NFNL_BATCH_REPLAY       = (1 << 2),
369 };
370 
371 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
372                                 u16 subsys_id, u32 genid)
373 {
374         struct sk_buff *oskb = skb;
375         struct net *net = sock_net(skb->sk);
376         const struct nfnetlink_subsystem *ss;
377         const struct nfnl_callback *nc;
378         struct netlink_ext_ack extack;
379         LIST_HEAD(err_list);
380         u32 status;
381         int err;
382 
383         if (subsys_id >= NFNL_SUBSYS_COUNT)
384                 return netlink_ack(skb, nlh, -EINVAL, NULL);
385 replay:
386         status = 0;
387 replay_abort:
388         skb = netlink_skb_clone(oskb, GFP_KERNEL);
389         if (!skb)
390                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
391 
392         nfnl_lock(subsys_id);
393         ss = nfnl_dereference_protected(subsys_id);
394         if (!ss) {
395 #ifdef CONFIG_MODULES
396                 nfnl_unlock(subsys_id);
397                 request_module("nfnetlink-subsys-%d", subsys_id);
398                 nfnl_lock(subsys_id);
399                 ss = nfnl_dereference_protected(subsys_id);
400                 if (!ss)
401 #endif
402                 {
403                         nfnl_unlock(subsys_id);
404                         netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
405                         return kfree_skb(skb);
406                 }
407         }
408 
409         if (!ss->valid_genid || !ss->commit || !ss->abort) {
410                 nfnl_unlock(subsys_id);
411                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
412                 return kfree_skb(skb);
413         }
414 
415         if (!try_module_get(ss->owner)) {
416                 nfnl_unlock(subsys_id);
417                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
418                 return kfree_skb(skb);
419         }
420 
421         if (!ss->valid_genid(net, genid)) {
422                 module_put(ss->owner);
423                 nfnl_unlock(subsys_id);
424                 netlink_ack(oskb, nlh, -ERESTART, NULL);
425                 return kfree_skb(skb);
426         }
427 
428         nfnl_unlock(subsys_id);
429 
430         if (nlh->nlmsg_flags & NLM_F_ACK) {
431                 memset(&extack, 0, sizeof(extack));
432                 nfnl_err_add(&err_list, nlh, 0, &extack);
433         }
434 
435         while (skb->len >= nlmsg_total_size(0)) {
436                 int msglen, type;
437 
438                 if (fatal_signal_pending(current)) {
439                         nfnl_err_reset(&err_list);
440                         err = -EINTR;
441                         status = NFNL_BATCH_FAILURE;
442                         goto done;
443                 }
444 
445                 memset(&extack, 0, sizeof(extack));
446                 nlh = nlmsg_hdr(skb);
447                 err = 0;
448 
449                 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
450                     skb->len < nlh->nlmsg_len ||
451                     nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
452                         nfnl_err_reset(&err_list);
453                         status |= NFNL_BATCH_FAILURE;
454                         goto done;
455                 }
456 
457                 /* Only requests are handled by the kernel */
458                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
459                         err = -EINVAL;
460                         goto ack;
461                 }
462 
463                 type = nlh->nlmsg_type;
464                 if (type == NFNL_MSG_BATCH_BEGIN) {
465                         /* Malformed: Batch begin twice */
466                         nfnl_err_reset(&err_list);
467                         status |= NFNL_BATCH_FAILURE;
468                         goto done;
469                 } else if (type == NFNL_MSG_BATCH_END) {
470                         status |= NFNL_BATCH_DONE;
471                         goto done;
472                 } else if (type < NLMSG_MIN_TYPE) {
473                         err = -EINVAL;
474                         goto ack;
475                 }
476 
477                 /* We only accept a batch with messages for the same
478                  * subsystem.
479                  */
480                 if (NFNL_SUBSYS_ID(type) != subsys_id) {
481                         err = -EINVAL;
482                         goto ack;
483                 }
484 
485                 nc = nfnetlink_find_client(type, ss);
486                 if (!nc) {
487                         err = -EINVAL;
488                         goto ack;
489                 }
490 
491                 if (nc->type != NFNL_CB_BATCH) {
492                         err = -EINVAL;
493                         goto ack;
494                 }
495 
496                 {
497                         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
498                         struct nfnl_net *nfnlnet = nfnl_pernet(net);
499                         struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
500                         struct nlattr *attr = (void *)nlh + min_len;
501                         u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
502                         int attrlen = nlh->nlmsg_len - min_len;
503                         struct nfnl_info info = {
504                                 .net    = net,
505                                 .sk     = nfnlnet->nfnl,
506                                 .nlh    = nlh,
507                                 .nfmsg  = nlmsg_data(nlh),
508                                 .extack = &extack,
509                         };
510 
511                         /* Sanity-check NFTA_MAX_ATTR */
512                         if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
513                                 err = -ENOMEM;
514                                 goto ack;
515                         }
516 
517                         err = nla_parse_deprecated(cda,
518                                                    ss->cb[cb_id].attr_count,
519                                                    attr, attrlen,
520                                                    ss->cb[cb_id].policy, NULL);
521                         if (err < 0)
522                                 goto ack;
523 
524                         err = nc->call(skb, &info, (const struct nlattr **)cda);
525 
526                         /* The lock was released to autoload some module, we
527                          * have to abort and start from scratch using the
528                          * original skb.
529                          */
530                         if (err == -EAGAIN) {
531                                 status |= NFNL_BATCH_REPLAY;
532                                 goto done;
533                         }
534                 }
535 ack:
536                 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
537                         /* Errors are delivered once the full batch has been
538                          * processed, this avoids that the same error is
539                          * reported several times when replaying the batch.
540                          */
541                         if (err == -ENOMEM ||
542                             nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
543                                 /* We failed to enqueue an error, reset the
544                                  * list of errors and send OOM to userspace
545                                  * pointing to the batch header.
546                                  */
547                                 nfnl_err_reset(&err_list);
548                                 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
549                                             NULL);
550                                 status |= NFNL_BATCH_FAILURE;
551                                 goto done;
552                         }
553                         /* We don't stop processing the batch on errors, thus,
554                          * userspace gets all the errors that the batch
555                          * triggers.
556                          */
557                         if (err)
558                                 status |= NFNL_BATCH_FAILURE;
559                 }
560 
561                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
562                 if (msglen > skb->len)
563                         msglen = skb->len;
564                 skb_pull(skb, msglen);
565         }
566 done:
567         if (status & NFNL_BATCH_REPLAY) {
568                 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
569                 nfnl_err_reset(&err_list);
570                 kfree_skb(skb);
571                 module_put(ss->owner);
572                 goto replay;
573         } else if (status == NFNL_BATCH_DONE) {
574                 err = ss->commit(net, oskb);
575                 if (err == -EAGAIN) {
576                         status |= NFNL_BATCH_REPLAY;
577                         goto done;
578                 } else if (err) {
579                         ss->abort(net, oskb, NFNL_ABORT_NONE);
580                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
581                 } else if (nlh->nlmsg_flags & NLM_F_ACK) {
582                         memset(&extack, 0, sizeof(extack));
583                         nfnl_err_add(&err_list, nlh, 0, &extack);
584                 }
585         } else {
586                 enum nfnl_abort_action abort_action;
587 
588                 if (status & NFNL_BATCH_FAILURE)
589                         abort_action = NFNL_ABORT_NONE;
590                 else
591                         abort_action = NFNL_ABORT_VALIDATE;
592 
593                 err = ss->abort(net, oskb, abort_action);
594                 if (err == -EAGAIN) {
595                         nfnl_err_reset(&err_list);
596                         kfree_skb(skb);
597                         module_put(ss->owner);
598                         status |= NFNL_BATCH_FAILURE;
599                         goto replay_abort;
600                 }
601         }
602 
603         nfnl_err_deliver(&err_list, oskb);
604         kfree_skb(skb);
605         module_put(ss->owner);
606 }
607 
608 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
609         [NFNL_BATCH_GENID]      = { .type = NLA_U32 },
610 };
611 
612 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
613 {
614         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
615         struct nlattr *attr = (void *)nlh + min_len;
616         struct nlattr *cda[NFNL_BATCH_MAX + 1];
617         int attrlen = nlh->nlmsg_len - min_len;
618         struct nfgenmsg *nfgenmsg;
619         int msglen, err;
620         u32 gen_id = 0;
621         u16 res_id;
622 
623         msglen = NLMSG_ALIGN(nlh->nlmsg_len);
624         if (msglen > skb->len)
625                 msglen = skb->len;
626 
627         if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
628                 return;
629 
630         err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
631                                    nfnl_batch_policy, NULL);
632         if (err < 0) {
633                 netlink_ack(skb, nlh, err, NULL);
634                 return;
635         }
636         if (cda[NFNL_BATCH_GENID])
637                 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
638 
639         nfgenmsg = nlmsg_data(nlh);
640         skb_pull(skb, msglen);
641         /* Work around old nft using host byte order */
642         if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES)
643                 res_id = NFNL_SUBSYS_NFTABLES;
644         else
645                 res_id = ntohs(nfgenmsg->res_id);
646 
647         nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
648 }
649 
650 static void nfnetlink_rcv(struct sk_buff *skb)
651 {
652         struct nlmsghdr *nlh = nlmsg_hdr(skb);
653 
654         if (skb->len < NLMSG_HDRLEN ||
655             nlh->nlmsg_len < NLMSG_HDRLEN ||
656             skb->len < nlh->nlmsg_len)
657                 return;
658 
659         if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
660                 netlink_ack(skb, nlh, -EPERM, NULL);
661                 return;
662         }
663 
664         if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
665                 nfnetlink_rcv_skb_batch(skb, nlh);
666         else
667                 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
668 }
669 
670 static void nfnetlink_bind_event(struct net *net, unsigned int group)
671 {
672 #ifdef CONFIG_NF_CONNTRACK_EVENTS
673         int type, group_bit;
674         u8 v;
675 
676         /* All NFNLGRP_CONNTRACK_* group bits fit into u8.
677          * The other groups are not relevant and can be ignored.
678          */
679         if (group >= 8)
680                 return;
681 
682         type = nfnl_group2type[group];
683 
684         switch (type) {
685         case NFNL_SUBSYS_CTNETLINK:
686                 break;
687         case NFNL_SUBSYS_CTNETLINK_EXP:
688                 break;
689         default:
690                 return;
691         }
692 
693         group_bit = (1 << group);
694 
695         spin_lock(&nfnl_grp_active_lock);
696         v = READ_ONCE(nf_ctnetlink_has_listener);
697         if ((v & group_bit) == 0) {
698                 v |= group_bit;
699 
700                 /* read concurrently without nfnl_grp_active_lock held. */
701                 WRITE_ONCE(nf_ctnetlink_has_listener, v);
702         }
703 
704         spin_unlock(&nfnl_grp_active_lock);
705 #endif
706 }
707 
708 static int nfnetlink_bind(struct net *net, int group)
709 {
710         const struct nfnetlink_subsystem *ss;
711         int type;
712 
713         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
714                 return 0;
715 
716         type = nfnl_group2type[group];
717 
718         rcu_read_lock();
719         ss = nfnetlink_get_subsys(type << 8);
720         rcu_read_unlock();
721         if (!ss)
722                 request_module_nowait("nfnetlink-subsys-%d", type);
723 
724         nfnetlink_bind_event(net, group);
725         return 0;
726 }
727 
728 static void nfnetlink_unbind(struct net *net, int group)
729 {
730 #ifdef CONFIG_NF_CONNTRACK_EVENTS
731         int type, group_bit;
732 
733         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
734                 return;
735 
736         type = nfnl_group2type[group];
737 
738         switch (type) {
739         case NFNL_SUBSYS_CTNETLINK:
740                 break;
741         case NFNL_SUBSYS_CTNETLINK_EXP:
742                 break;
743         default:
744                 return;
745         }
746 
747         /* ctnetlink_has_listener is u8 */
748         if (group >= 8)
749                 return;
750 
751         group_bit = (1 << group);
752 
753         spin_lock(&nfnl_grp_active_lock);
754         if (!nfnetlink_has_listeners(net, group)) {
755                 u8 v = READ_ONCE(nf_ctnetlink_has_listener);
756 
757                 v &= ~group_bit;
758 
759                 /* read concurrently without nfnl_grp_active_lock held. */
760                 WRITE_ONCE(nf_ctnetlink_has_listener, v);
761         }
762         spin_unlock(&nfnl_grp_active_lock);
763 #endif
764 }
765 
766 static int __net_init nfnetlink_net_init(struct net *net)
767 {
768         struct nfnl_net *nfnlnet = nfnl_pernet(net);
769         struct netlink_kernel_cfg cfg = {
770                 .groups = NFNLGRP_MAX,
771                 .input  = nfnetlink_rcv,
772                 .bind   = nfnetlink_bind,
773                 .unbind = nfnetlink_unbind,
774         };
775 
776         nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
777         if (!nfnlnet->nfnl)
778                 return -ENOMEM;
779         return 0;
780 }
781 
782 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
783 {
784         struct nfnl_net *nfnlnet;
785         struct net *net;
786 
787         list_for_each_entry(net, net_exit_list, exit_list) {
788                 nfnlnet = nfnl_pernet(net);
789 
790                 netlink_kernel_release(nfnlnet->nfnl);
791         }
792 }
793 
794 static struct pernet_operations nfnetlink_net_ops = {
795         .init           = nfnetlink_net_init,
796         .exit_batch     = nfnetlink_net_exit_batch,
797         .id             = &nfnetlink_pernet_id,
798         .size           = sizeof(struct nfnl_net),
799 };
800 
801 static int __init nfnetlink_init(void)
802 {
803         int i;
804 
805         for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
806                 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
807 
808         for (i=0; i<NFNL_SUBSYS_COUNT; i++)
809                 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
810 
811         return register_pernet_subsys(&nfnetlink_net_ops);
812 }
813 
814 static void __exit nfnetlink_exit(void)
815 {
816         unregister_pernet_subsys(&nfnetlink_net_ops);
817 }
818 module_init(nfnetlink_init);
819 module_exit(nfnetlink_exit);
820 

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