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Linux/net/core/fib_rules.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * net/core/fib_rules.c         Generic Routing Rules
  4  *
  5  * Authors:     Thomas Graf <tgraf@suug.ch>
  6  */
  7 
  8 #include <linux/types.h>
  9 #include <linux/kernel.h>
 10 #include <linux/slab.h>
 11 #include <linux/list.h>
 12 #include <linux/module.h>
 13 #include <net/net_namespace.h>
 14 #include <net/sock.h>
 15 #include <net/fib_rules.h>
 16 #include <net/ip_tunnels.h>
 17 
 18 static const struct fib_kuid_range fib_kuid_range_unset = {
 19         KUIDT_INIT(0),
 20         KUIDT_INIT(~0),
 21 };
 22 
 23 bool fib_rule_matchall(const struct fib_rule *rule)
 24 {
 25         if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
 26             rule->flags)
 27                 return false;
 28         if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
 29                 return false;
 30         if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
 31             !uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
 32                 return false;
 33         if (fib_rule_port_range_set(&rule->sport_range))
 34                 return false;
 35         if (fib_rule_port_range_set(&rule->dport_range))
 36                 return false;
 37         return true;
 38 }
 39 EXPORT_SYMBOL_GPL(fib_rule_matchall);
 40 
 41 int fib_default_rule_add(struct fib_rules_ops *ops,
 42                          u32 pref, u32 table, u32 flags)
 43 {
 44         struct fib_rule *r;
 45 
 46         r = kzalloc(ops->rule_size, GFP_KERNEL);
 47         if (r == NULL)
 48                 return -ENOMEM;
 49 
 50         refcount_set(&r->refcnt, 1);
 51         r->action = FR_ACT_TO_TBL;
 52         r->pref = pref;
 53         r->table = table;
 54         r->flags = flags;
 55         r->proto = RTPROT_KERNEL;
 56         r->fr_net = ops->fro_net;
 57         r->uid_range = fib_kuid_range_unset;
 58 
 59         r->suppress_prefixlen = -1;
 60         r->suppress_ifgroup = -1;
 61 
 62         /* The lock is not required here, the list in unreacheable
 63          * at the moment this function is called */
 64         list_add_tail(&r->list, &ops->rules_list);
 65         return 0;
 66 }
 67 EXPORT_SYMBOL(fib_default_rule_add);
 68 
 69 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
 70 {
 71         struct list_head *pos;
 72         struct fib_rule *rule;
 73 
 74         if (!list_empty(&ops->rules_list)) {
 75                 pos = ops->rules_list.next;
 76                 if (pos->next != &ops->rules_list) {
 77                         rule = list_entry(pos->next, struct fib_rule, list);
 78                         if (rule->pref)
 79                                 return rule->pref - 1;
 80                 }
 81         }
 82 
 83         return 0;
 84 }
 85 
 86 static void notify_rule_change(int event, struct fib_rule *rule,
 87                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
 88                                u32 pid);
 89 
 90 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
 91 {
 92         struct fib_rules_ops *ops;
 93 
 94         rcu_read_lock();
 95         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
 96                 if (ops->family == family) {
 97                         if (!try_module_get(ops->owner))
 98                                 ops = NULL;
 99                         rcu_read_unlock();
100                         return ops;
101                 }
102         }
103         rcu_read_unlock();
104 
105         return NULL;
106 }
107 
108 static void rules_ops_put(struct fib_rules_ops *ops)
109 {
110         if (ops)
111                 module_put(ops->owner);
112 }
113 
114 static void flush_route_cache(struct fib_rules_ops *ops)
115 {
116         if (ops->flush_cache)
117                 ops->flush_cache(ops);
118 }
119 
120 static int __fib_rules_register(struct fib_rules_ops *ops)
121 {
122         int err = -EEXIST;
123         struct fib_rules_ops *o;
124         struct net *net;
125 
126         net = ops->fro_net;
127 
128         if (ops->rule_size < sizeof(struct fib_rule))
129                 return -EINVAL;
130 
131         if (ops->match == NULL || ops->configure == NULL ||
132             ops->compare == NULL || ops->fill == NULL ||
133             ops->action == NULL)
134                 return -EINVAL;
135 
136         spin_lock(&net->rules_mod_lock);
137         list_for_each_entry(o, &net->rules_ops, list)
138                 if (ops->family == o->family)
139                         goto errout;
140 
141         list_add_tail_rcu(&ops->list, &net->rules_ops);
142         err = 0;
143 errout:
144         spin_unlock(&net->rules_mod_lock);
145 
146         return err;
147 }
148 
149 struct fib_rules_ops *
150 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
151 {
152         struct fib_rules_ops *ops;
153         int err;
154 
155         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
156         if (ops == NULL)
157                 return ERR_PTR(-ENOMEM);
158 
159         INIT_LIST_HEAD(&ops->rules_list);
160         ops->fro_net = net;
161 
162         err = __fib_rules_register(ops);
163         if (err) {
164                 kfree(ops);
165                 ops = ERR_PTR(err);
166         }
167 
168         return ops;
169 }
170 EXPORT_SYMBOL_GPL(fib_rules_register);
171 
172 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
173 {
174         struct fib_rule *rule, *tmp;
175 
176         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
177                 list_del_rcu(&rule->list);
178                 if (ops->delete)
179                         ops->delete(rule);
180                 fib_rule_put(rule);
181         }
182 }
183 
184 void fib_rules_unregister(struct fib_rules_ops *ops)
185 {
186         struct net *net = ops->fro_net;
187 
188         spin_lock(&net->rules_mod_lock);
189         list_del_rcu(&ops->list);
190         spin_unlock(&net->rules_mod_lock);
191 
192         fib_rules_cleanup_ops(ops);
193         kfree_rcu(ops, rcu);
194 }
195 EXPORT_SYMBOL_GPL(fib_rules_unregister);
196 
197 static int uid_range_set(struct fib_kuid_range *range)
198 {
199         return uid_valid(range->start) && uid_valid(range->end);
200 }
201 
202 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
203 {
204         struct fib_rule_uid_range *in;
205         struct fib_kuid_range out;
206 
207         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
208 
209         out.start = make_kuid(current_user_ns(), in->start);
210         out.end = make_kuid(current_user_ns(), in->end);
211 
212         return out;
213 }
214 
215 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
216 {
217         struct fib_rule_uid_range out = {
218                 from_kuid_munged(current_user_ns(), range->start),
219                 from_kuid_munged(current_user_ns(), range->end)
220         };
221 
222         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
223 }
224 
225 static int nla_get_port_range(struct nlattr *pattr,
226                               struct fib_rule_port_range *port_range)
227 {
228         const struct fib_rule_port_range *pr = nla_data(pattr);
229 
230         if (!fib_rule_port_range_valid(pr))
231                 return -EINVAL;
232 
233         port_range->start = pr->start;
234         port_range->end = pr->end;
235 
236         return 0;
237 }
238 
239 static int nla_put_port_range(struct sk_buff *skb, int attrtype,
240                               struct fib_rule_port_range *range)
241 {
242         return nla_put(skb, attrtype, sizeof(*range), range);
243 }
244 
245 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
246                           struct flowi *fl, int flags,
247                           struct fib_lookup_arg *arg)
248 {
249         int ret = 0;
250 
251         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
252                 goto out;
253 
254         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
255                 goto out;
256 
257         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
258                 goto out;
259 
260         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
261                 goto out;
262 
263         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
264                 goto out;
265 
266         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
267             uid_gt(fl->flowi_uid, rule->uid_range.end))
268                 goto out;
269 
270         ret = ops->match(rule, fl, flags);
271 out:
272         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
273 }
274 
275 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
276                      int flags, struct fib_lookup_arg *arg)
277 {
278         struct fib_rule *rule;
279         int err;
280 
281         rcu_read_lock();
282 
283         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
284 jumped:
285                 if (!fib_rule_match(rule, ops, fl, flags, arg))
286                         continue;
287 
288                 if (rule->action == FR_ACT_GOTO) {
289                         struct fib_rule *target;
290 
291                         target = rcu_dereference(rule->ctarget);
292                         if (target == NULL) {
293                                 continue;
294                         } else {
295                                 rule = target;
296                                 goto jumped;
297                         }
298                 } else if (rule->action == FR_ACT_NOP)
299                         continue;
300                 else
301                         err = ops->action(rule, fl, flags, arg);
302 
303                 if (!err && ops->suppress && ops->suppress(rule, arg))
304                         continue;
305 
306                 if (err != -EAGAIN) {
307                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
308                             likely(refcount_inc_not_zero(&rule->refcnt))) {
309                                 arg->rule = rule;
310                                 goto out;
311                         }
312                         break;
313                 }
314         }
315 
316         err = -ESRCH;
317 out:
318         rcu_read_unlock();
319 
320         return err;
321 }
322 EXPORT_SYMBOL_GPL(fib_rules_lookup);
323 
324 static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
325                                   enum fib_event_type event_type,
326                                   struct fib_rule *rule, int family)
327 {
328         struct fib_rule_notifier_info info = {
329                 .info.family = family,
330                 .rule = rule,
331         };
332 
333         return call_fib_notifier(nb, net, event_type, &info.info);
334 }
335 
336 static int call_fib_rule_notifiers(struct net *net,
337                                    enum fib_event_type event_type,
338                                    struct fib_rule *rule,
339                                    struct fib_rules_ops *ops,
340                                    struct netlink_ext_ack *extack)
341 {
342         struct fib_rule_notifier_info info = {
343                 .info.family = ops->family,
344                 .info.extack = extack,
345                 .rule = rule,
346         };
347 
348         ops->fib_rules_seq++;
349         return call_fib_notifiers(net, event_type, &info.info);
350 }
351 
352 /* Called with rcu_read_lock() */
353 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
354 {
355         struct fib_rules_ops *ops;
356         struct fib_rule *rule;
357 
358         ops = lookup_rules_ops(net, family);
359         if (!ops)
360                 return -EAFNOSUPPORT;
361         list_for_each_entry_rcu(rule, &ops->rules_list, list)
362                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
363                                        family);
364         rules_ops_put(ops);
365 
366         return 0;
367 }
368 EXPORT_SYMBOL_GPL(fib_rules_dump);
369 
370 unsigned int fib_rules_seq_read(struct net *net, int family)
371 {
372         unsigned int fib_rules_seq;
373         struct fib_rules_ops *ops;
374 
375         ASSERT_RTNL();
376 
377         ops = lookup_rules_ops(net, family);
378         if (!ops)
379                 return 0;
380         fib_rules_seq = ops->fib_rules_seq;
381         rules_ops_put(ops);
382 
383         return fib_rules_seq;
384 }
385 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
386 
387 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
388                                   struct fib_rule_hdr *frh,
389                                   struct nlattr **tb,
390                                   struct fib_rule *rule,
391                                   bool user_priority)
392 {
393         struct fib_rule *r;
394 
395         list_for_each_entry(r, &ops->rules_list, list) {
396                 if (rule->action && r->action != rule->action)
397                         continue;
398 
399                 if (rule->table && r->table != rule->table)
400                         continue;
401 
402                 if (user_priority && r->pref != rule->pref)
403                         continue;
404 
405                 if (rule->iifname[0] &&
406                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
407                         continue;
408 
409                 if (rule->oifname[0] &&
410                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
411                         continue;
412 
413                 if (rule->mark && r->mark != rule->mark)
414                         continue;
415 
416                 if (rule->suppress_ifgroup != -1 &&
417                     r->suppress_ifgroup != rule->suppress_ifgroup)
418                         continue;
419 
420                 if (rule->suppress_prefixlen != -1 &&
421                     r->suppress_prefixlen != rule->suppress_prefixlen)
422                         continue;
423 
424                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
425                         continue;
426 
427                 if (rule->tun_id && r->tun_id != rule->tun_id)
428                         continue;
429 
430                 if (r->fr_net != rule->fr_net)
431                         continue;
432 
433                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
434                         continue;
435 
436                 if (uid_range_set(&rule->uid_range) &&
437                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
438                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
439                         continue;
440 
441                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
442                         continue;
443 
444                 if (rule->proto && r->proto != rule->proto)
445                         continue;
446 
447                 if (fib_rule_port_range_set(&rule->sport_range) &&
448                     !fib_rule_port_range_compare(&r->sport_range,
449                                                  &rule->sport_range))
450                         continue;
451 
452                 if (fib_rule_port_range_set(&rule->dport_range) &&
453                     !fib_rule_port_range_compare(&r->dport_range,
454                                                  &rule->dport_range))
455                         continue;
456 
457                 if (!ops->compare(r, frh, tb))
458                         continue;
459                 return r;
460         }
461 
462         return NULL;
463 }
464 
465 #ifdef CONFIG_NET_L3_MASTER_DEV
466 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
467                               struct netlink_ext_ack *extack)
468 {
469         nlrule->l3mdev = nla_get_u8(nla);
470         if (nlrule->l3mdev != 1) {
471                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
472                 return -1;
473         }
474 
475         return 0;
476 }
477 #else
478 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
479                               struct netlink_ext_ack *extack)
480 {
481         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
482         return -1;
483 }
484 #endif
485 
486 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
487                        struct netlink_ext_ack *extack,
488                        struct fib_rules_ops *ops,
489                        struct nlattr *tb[],
490                        struct fib_rule **rule,
491                        bool *user_priority)
492 {
493         struct net *net = sock_net(skb->sk);
494         struct fib_rule_hdr *frh = nlmsg_data(nlh);
495         struct fib_rule *nlrule = NULL;
496         int err = -EINVAL;
497 
498         if (frh->src_len)
499                 if (!tb[FRA_SRC] ||
500                     frh->src_len > (ops->addr_size * 8) ||
501                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
502                         NL_SET_ERR_MSG(extack, "Invalid source address");
503                         goto errout;
504         }
505 
506         if (frh->dst_len)
507                 if (!tb[FRA_DST] ||
508                     frh->dst_len > (ops->addr_size * 8) ||
509                     nla_len(tb[FRA_DST]) != ops->addr_size) {
510                         NL_SET_ERR_MSG(extack, "Invalid dst address");
511                         goto errout;
512         }
513 
514         nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
515         if (!nlrule) {
516                 err = -ENOMEM;
517                 goto errout;
518         }
519         refcount_set(&nlrule->refcnt, 1);
520         nlrule->fr_net = net;
521 
522         if (tb[FRA_PRIORITY]) {
523                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
524                 *user_priority = true;
525         } else {
526                 nlrule->pref = fib_default_rule_pref(ops);
527         }
528 
529         nlrule->proto = tb[FRA_PROTOCOL] ?
530                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
531 
532         if (tb[FRA_IIFNAME]) {
533                 struct net_device *dev;
534 
535                 nlrule->iifindex = -1;
536                 nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
537                 dev = __dev_get_by_name(net, nlrule->iifname);
538                 if (dev)
539                         nlrule->iifindex = dev->ifindex;
540         }
541 
542         if (tb[FRA_OIFNAME]) {
543                 struct net_device *dev;
544 
545                 nlrule->oifindex = -1;
546                 nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
547                 dev = __dev_get_by_name(net, nlrule->oifname);
548                 if (dev)
549                         nlrule->oifindex = dev->ifindex;
550         }
551 
552         if (tb[FRA_FWMARK]) {
553                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
554                 if (nlrule->mark)
555                         /* compatibility: if the mark value is non-zero all bits
556                          * are compared unless a mask is explicitly specified.
557                          */
558                         nlrule->mark_mask = 0xFFFFFFFF;
559         }
560 
561         if (tb[FRA_FWMASK])
562                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
563 
564         if (tb[FRA_TUN_ID])
565                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
566 
567         err = -EINVAL;
568         if (tb[FRA_L3MDEV] &&
569             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
570                 goto errout_free;
571 
572         nlrule->action = frh->action;
573         nlrule->flags = frh->flags;
574         nlrule->table = frh_get_table(frh, tb);
575         if (tb[FRA_SUPPRESS_PREFIXLEN])
576                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
577         else
578                 nlrule->suppress_prefixlen = -1;
579 
580         if (tb[FRA_SUPPRESS_IFGROUP])
581                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
582         else
583                 nlrule->suppress_ifgroup = -1;
584 
585         if (tb[FRA_GOTO]) {
586                 if (nlrule->action != FR_ACT_GOTO) {
587                         NL_SET_ERR_MSG(extack, "Unexpected goto");
588                         goto errout_free;
589                 }
590 
591                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
592                 /* Backward jumps are prohibited to avoid endless loops */
593                 if (nlrule->target <= nlrule->pref) {
594                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
595                         goto errout_free;
596                 }
597         } else if (nlrule->action == FR_ACT_GOTO) {
598                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
599                 goto errout_free;
600         }
601 
602         if (nlrule->l3mdev && nlrule->table) {
603                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
604                 goto errout_free;
605         }
606 
607         if (tb[FRA_UID_RANGE]) {
608                 if (current_user_ns() != net->user_ns) {
609                         err = -EPERM;
610                         NL_SET_ERR_MSG(extack, "No permission to set uid");
611                         goto errout_free;
612                 }
613 
614                 nlrule->uid_range = nla_get_kuid_range(tb);
615 
616                 if (!uid_range_set(&nlrule->uid_range) ||
617                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
618                         NL_SET_ERR_MSG(extack, "Invalid uid range");
619                         goto errout_free;
620                 }
621         } else {
622                 nlrule->uid_range = fib_kuid_range_unset;
623         }
624 
625         if (tb[FRA_IP_PROTO])
626                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
627 
628         if (tb[FRA_SPORT_RANGE]) {
629                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
630                                          &nlrule->sport_range);
631                 if (err) {
632                         NL_SET_ERR_MSG(extack, "Invalid sport range");
633                         goto errout_free;
634                 }
635         }
636 
637         if (tb[FRA_DPORT_RANGE]) {
638                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
639                                          &nlrule->dport_range);
640                 if (err) {
641                         NL_SET_ERR_MSG(extack, "Invalid dport range");
642                         goto errout_free;
643                 }
644         }
645 
646         *rule = nlrule;
647 
648         return 0;
649 
650 errout_free:
651         kfree(nlrule);
652 errout:
653         return err;
654 }
655 
656 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
657                        struct nlattr **tb, struct fib_rule *rule)
658 {
659         struct fib_rule *r;
660 
661         list_for_each_entry(r, &ops->rules_list, list) {
662                 if (r->action != rule->action)
663                         continue;
664 
665                 if (r->table != rule->table)
666                         continue;
667 
668                 if (r->pref != rule->pref)
669                         continue;
670 
671                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
672                         continue;
673 
674                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
675                         continue;
676 
677                 if (r->mark != rule->mark)
678                         continue;
679 
680                 if (r->suppress_ifgroup != rule->suppress_ifgroup)
681                         continue;
682 
683                 if (r->suppress_prefixlen != rule->suppress_prefixlen)
684                         continue;
685 
686                 if (r->mark_mask != rule->mark_mask)
687                         continue;
688 
689                 if (r->tun_id != rule->tun_id)
690                         continue;
691 
692                 if (r->fr_net != rule->fr_net)
693                         continue;
694 
695                 if (r->l3mdev != rule->l3mdev)
696                         continue;
697 
698                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
699                     !uid_eq(r->uid_range.end, rule->uid_range.end))
700                         continue;
701 
702                 if (r->ip_proto != rule->ip_proto)
703                         continue;
704 
705                 if (r->proto != rule->proto)
706                         continue;
707 
708                 if (!fib_rule_port_range_compare(&r->sport_range,
709                                                  &rule->sport_range))
710                         continue;
711 
712                 if (!fib_rule_port_range_compare(&r->dport_range,
713                                                  &rule->dport_range))
714                         continue;
715 
716                 if (!ops->compare(r, frh, tb))
717                         continue;
718                 return 1;
719         }
720         return 0;
721 }
722 
723 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
724                    struct netlink_ext_ack *extack)
725 {
726         struct net *net = sock_net(skb->sk);
727         struct fib_rule_hdr *frh = nlmsg_data(nlh);
728         struct fib_rules_ops *ops = NULL;
729         struct fib_rule *rule = NULL, *r, *last = NULL;
730         struct nlattr *tb[FRA_MAX + 1];
731         int err = -EINVAL, unresolved = 0;
732         bool user_priority = false;
733 
734         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
735                 NL_SET_ERR_MSG(extack, "Invalid msg length");
736                 goto errout;
737         }
738 
739         ops = lookup_rules_ops(net, frh->family);
740         if (!ops) {
741                 err = -EAFNOSUPPORT;
742                 NL_SET_ERR_MSG(extack, "Rule family not supported");
743                 goto errout;
744         }
745 
746         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
747                                      ops->policy, extack);
748         if (err < 0) {
749                 NL_SET_ERR_MSG(extack, "Error parsing msg");
750                 goto errout;
751         }
752 
753         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
754         if (err)
755                 goto errout;
756 
757         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
758             rule_exists(ops, frh, tb, rule)) {
759                 err = -EEXIST;
760                 goto errout_free;
761         }
762 
763         err = ops->configure(rule, skb, frh, tb, extack);
764         if (err < 0)
765                 goto errout_free;
766 
767         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
768                                       extack);
769         if (err < 0)
770                 goto errout_free;
771 
772         list_for_each_entry(r, &ops->rules_list, list) {
773                 if (r->pref == rule->target) {
774                         RCU_INIT_POINTER(rule->ctarget, r);
775                         break;
776                 }
777         }
778 
779         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
780                 unresolved = 1;
781 
782         list_for_each_entry(r, &ops->rules_list, list) {
783                 if (r->pref > rule->pref)
784                         break;
785                 last = r;
786         }
787 
788         if (last)
789                 list_add_rcu(&rule->list, &last->list);
790         else
791                 list_add_rcu(&rule->list, &ops->rules_list);
792 
793         if (ops->unresolved_rules) {
794                 /*
795                  * There are unresolved goto rules in the list, check if
796                  * any of them are pointing to this new rule.
797                  */
798                 list_for_each_entry(r, &ops->rules_list, list) {
799                         if (r->action == FR_ACT_GOTO &&
800                             r->target == rule->pref &&
801                             rtnl_dereference(r->ctarget) == NULL) {
802                                 rcu_assign_pointer(r->ctarget, rule);
803                                 if (--ops->unresolved_rules == 0)
804                                         break;
805                         }
806                 }
807         }
808 
809         if (rule->action == FR_ACT_GOTO)
810                 ops->nr_goto_rules++;
811 
812         if (unresolved)
813                 ops->unresolved_rules++;
814 
815         if (rule->tun_id)
816                 ip_tunnel_need_metadata();
817 
818         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
819         flush_route_cache(ops);
820         rules_ops_put(ops);
821         return 0;
822 
823 errout_free:
824         kfree(rule);
825 errout:
826         rules_ops_put(ops);
827         return err;
828 }
829 EXPORT_SYMBOL_GPL(fib_nl_newrule);
830 
831 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
832                    struct netlink_ext_ack *extack)
833 {
834         struct net *net = sock_net(skb->sk);
835         struct fib_rule_hdr *frh = nlmsg_data(nlh);
836         struct fib_rules_ops *ops = NULL;
837         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
838         struct nlattr *tb[FRA_MAX+1];
839         int err = -EINVAL;
840         bool user_priority = false;
841 
842         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
843                 NL_SET_ERR_MSG(extack, "Invalid msg length");
844                 goto errout;
845         }
846 
847         ops = lookup_rules_ops(net, frh->family);
848         if (ops == NULL) {
849                 err = -EAFNOSUPPORT;
850                 NL_SET_ERR_MSG(extack, "Rule family not supported");
851                 goto errout;
852         }
853 
854         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
855                                      ops->policy, extack);
856         if (err < 0) {
857                 NL_SET_ERR_MSG(extack, "Error parsing msg");
858                 goto errout;
859         }
860 
861         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
862         if (err)
863                 goto errout;
864 
865         rule = rule_find(ops, frh, tb, nlrule, user_priority);
866         if (!rule) {
867                 err = -ENOENT;
868                 goto errout;
869         }
870 
871         if (rule->flags & FIB_RULE_PERMANENT) {
872                 err = -EPERM;
873                 goto errout;
874         }
875 
876         if (ops->delete) {
877                 err = ops->delete(rule);
878                 if (err)
879                         goto errout;
880         }
881 
882         if (rule->tun_id)
883                 ip_tunnel_unneed_metadata();
884 
885         list_del_rcu(&rule->list);
886 
887         if (rule->action == FR_ACT_GOTO) {
888                 ops->nr_goto_rules--;
889                 if (rtnl_dereference(rule->ctarget) == NULL)
890                         ops->unresolved_rules--;
891         }
892 
893         /*
894          * Check if this rule is a target to any of them. If so,
895          * adjust to the next one with the same preference or
896          * disable them. As this operation is eventually very
897          * expensive, it is only performed if goto rules, except
898          * current if it is goto rule, have actually been added.
899          */
900         if (ops->nr_goto_rules > 0) {
901                 struct fib_rule *n;
902 
903                 n = list_next_entry(rule, list);
904                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
905                         n = NULL;
906                 list_for_each_entry(r, &ops->rules_list, list) {
907                         if (rtnl_dereference(r->ctarget) != rule)
908                                 continue;
909                         rcu_assign_pointer(r->ctarget, n);
910                         if (!n)
911                                 ops->unresolved_rules++;
912                 }
913         }
914 
915         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
916                                 NULL);
917         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
918                            NETLINK_CB(skb).portid);
919         fib_rule_put(rule);
920         flush_route_cache(ops);
921         rules_ops_put(ops);
922         kfree(nlrule);
923         return 0;
924 
925 errout:
926         kfree(nlrule);
927         rules_ops_put(ops);
928         return err;
929 }
930 EXPORT_SYMBOL_GPL(fib_nl_delrule);
931 
932 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
933                                          struct fib_rule *rule)
934 {
935         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
936                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
937                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
938                          + nla_total_size(4) /* FRA_PRIORITY */
939                          + nla_total_size(4) /* FRA_TABLE */
940                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
941                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
942                          + nla_total_size(4) /* FRA_FWMARK */
943                          + nla_total_size(4) /* FRA_FWMASK */
944                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
945                          + nla_total_size(sizeof(struct fib_kuid_range))
946                          + nla_total_size(1) /* FRA_PROTOCOL */
947                          + nla_total_size(1) /* FRA_IP_PROTO */
948                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
949                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
950 
951         if (ops->nlmsg_payload)
952                 payload += ops->nlmsg_payload(rule);
953 
954         return payload;
955 }
956 
957 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
958                             u32 pid, u32 seq, int type, int flags,
959                             struct fib_rules_ops *ops)
960 {
961         struct nlmsghdr *nlh;
962         struct fib_rule_hdr *frh;
963 
964         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
965         if (nlh == NULL)
966                 return -EMSGSIZE;
967 
968         frh = nlmsg_data(nlh);
969         frh->family = ops->family;
970         frh->table = rule->table;
971         if (nla_put_u32(skb, FRA_TABLE, rule->table))
972                 goto nla_put_failure;
973         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
974                 goto nla_put_failure;
975         frh->res1 = 0;
976         frh->res2 = 0;
977         frh->action = rule->action;
978         frh->flags = rule->flags;
979 
980         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
981                 goto nla_put_failure;
982 
983         if (rule->action == FR_ACT_GOTO &&
984             rcu_access_pointer(rule->ctarget) == NULL)
985                 frh->flags |= FIB_RULE_UNRESOLVED;
986 
987         if (rule->iifname[0]) {
988                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
989                         goto nla_put_failure;
990                 if (rule->iifindex == -1)
991                         frh->flags |= FIB_RULE_IIF_DETACHED;
992         }
993 
994         if (rule->oifname[0]) {
995                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
996                         goto nla_put_failure;
997                 if (rule->oifindex == -1)
998                         frh->flags |= FIB_RULE_OIF_DETACHED;
999         }
1000 
1001         if ((rule->pref &&
1002              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
1003             (rule->mark &&
1004              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
1005             ((rule->mark_mask || rule->mark) &&
1006              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
1007             (rule->target &&
1008              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
1009             (rule->tun_id &&
1010              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
1011             (rule->l3mdev &&
1012              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
1013             (uid_range_set(&rule->uid_range) &&
1014              nla_put_uid_range(skb, &rule->uid_range)) ||
1015             (fib_rule_port_range_set(&rule->sport_range) &&
1016              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
1017             (fib_rule_port_range_set(&rule->dport_range) &&
1018              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
1019             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
1020                 goto nla_put_failure;
1021 
1022         if (rule->suppress_ifgroup != -1) {
1023                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
1024                         goto nla_put_failure;
1025         }
1026 
1027         if (ops->fill(rule, skb, frh) < 0)
1028                 goto nla_put_failure;
1029 
1030         nlmsg_end(skb, nlh);
1031         return 0;
1032 
1033 nla_put_failure:
1034         nlmsg_cancel(skb, nlh);
1035         return -EMSGSIZE;
1036 }
1037 
1038 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
1039                       struct fib_rules_ops *ops)
1040 {
1041         int idx = 0;
1042         struct fib_rule *rule;
1043         int err = 0;
1044 
1045         rcu_read_lock();
1046         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
1047                 if (idx < cb->args[1])
1048                         goto skip;
1049 
1050                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
1051                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
1052                                        NLM_F_MULTI, ops);
1053                 if (err)
1054                         break;
1055 skip:
1056                 idx++;
1057         }
1058         rcu_read_unlock();
1059         cb->args[1] = idx;
1060         rules_ops_put(ops);
1061 
1062         return err;
1063 }
1064 
1065 static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
1066                                    struct netlink_ext_ack *extack)
1067 {
1068         struct fib_rule_hdr *frh;
1069 
1070         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
1071                 NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
1072                 return -EINVAL;
1073         }
1074 
1075         frh = nlmsg_data(nlh);
1076         if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
1077             frh->res1 || frh->res2 || frh->action || frh->flags) {
1078                 NL_SET_ERR_MSG(extack,
1079                                "Invalid values in header for fib rule dump request");
1080                 return -EINVAL;
1081         }
1082 
1083         if (nlmsg_attrlen(nlh, sizeof(*frh))) {
1084                 NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
1085                 return -EINVAL;
1086         }
1087 
1088         return 0;
1089 }
1090 
1091 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
1092 {
1093         const struct nlmsghdr *nlh = cb->nlh;
1094         struct net *net = sock_net(skb->sk);
1095         struct fib_rules_ops *ops;
1096         int idx = 0, family;
1097 
1098         if (cb->strict_check) {
1099                 int err = fib_valid_dumprule_req(nlh, cb->extack);
1100 
1101                 if (err < 0)
1102                         return err;
1103         }
1104 
1105         family = rtnl_msg_family(nlh);
1106         if (family != AF_UNSPEC) {
1107                 /* Protocol specific dump request */
1108                 ops = lookup_rules_ops(net, family);
1109                 if (ops == NULL)
1110                         return -EAFNOSUPPORT;
1111 
1112                 dump_rules(skb, cb, ops);
1113 
1114                 return skb->len;
1115         }
1116 
1117         rcu_read_lock();
1118         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1119                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1120                         goto skip;
1121 
1122                 if (dump_rules(skb, cb, ops) < 0)
1123                         break;
1124 
1125                 cb->args[1] = 0;
1126 skip:
1127                 idx++;
1128         }
1129         rcu_read_unlock();
1130         cb->args[0] = idx;
1131 
1132         return skb->len;
1133 }
1134 
1135 static void notify_rule_change(int event, struct fib_rule *rule,
1136                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1137                                u32 pid)
1138 {
1139         struct net *net;
1140         struct sk_buff *skb;
1141         int err = -ENOBUFS;
1142 
1143         net = ops->fro_net;
1144         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1145         if (skb == NULL)
1146                 goto errout;
1147 
1148         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1149         if (err < 0) {
1150                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1151                 WARN_ON(err == -EMSGSIZE);
1152                 kfree_skb(skb);
1153                 goto errout;
1154         }
1155 
1156         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1157         return;
1158 errout:
1159         if (err < 0)
1160                 rtnl_set_sk_err(net, ops->nlgroup, err);
1161 }
1162 
1163 static void attach_rules(struct list_head *rules, struct net_device *dev)
1164 {
1165         struct fib_rule *rule;
1166 
1167         list_for_each_entry(rule, rules, list) {
1168                 if (rule->iifindex == -1 &&
1169                     strcmp(dev->name, rule->iifname) == 0)
1170                         rule->iifindex = dev->ifindex;
1171                 if (rule->oifindex == -1 &&
1172                     strcmp(dev->name, rule->oifname) == 0)
1173                         rule->oifindex = dev->ifindex;
1174         }
1175 }
1176 
1177 static void detach_rules(struct list_head *rules, struct net_device *dev)
1178 {
1179         struct fib_rule *rule;
1180 
1181         list_for_each_entry(rule, rules, list) {
1182                 if (rule->iifindex == dev->ifindex)
1183                         rule->iifindex = -1;
1184                 if (rule->oifindex == dev->ifindex)
1185                         rule->oifindex = -1;
1186         }
1187 }
1188 
1189 
1190 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1191                            void *ptr)
1192 {
1193         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1194         struct net *net = dev_net(dev);
1195         struct fib_rules_ops *ops;
1196 
1197         ASSERT_RTNL();
1198 
1199         switch (event) {
1200         case NETDEV_REGISTER:
1201                 list_for_each_entry(ops, &net->rules_ops, list)
1202                         attach_rules(&ops->rules_list, dev);
1203                 break;
1204 
1205         case NETDEV_CHANGENAME:
1206                 list_for_each_entry(ops, &net->rules_ops, list) {
1207                         detach_rules(&ops->rules_list, dev);
1208                         attach_rules(&ops->rules_list, dev);
1209                 }
1210                 break;
1211 
1212         case NETDEV_UNREGISTER:
1213                 list_for_each_entry(ops, &net->rules_ops, list)
1214                         detach_rules(&ops->rules_list, dev);
1215                 break;
1216         }
1217 
1218         return NOTIFY_DONE;
1219 }
1220 
1221 static struct notifier_block fib_rules_notifier = {
1222         .notifier_call = fib_rules_event,
1223 };
1224 
1225 static int __net_init fib_rules_net_init(struct net *net)
1226 {
1227         INIT_LIST_HEAD(&net->rules_ops);
1228         spin_lock_init(&net->rules_mod_lock);
1229         return 0;
1230 }
1231 
1232 static void __net_exit fib_rules_net_exit(struct net *net)
1233 {
1234         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1235 }
1236 
1237 static struct pernet_operations fib_rules_net_ops = {
1238         .init = fib_rules_net_init,
1239         .exit = fib_rules_net_exit,
1240 };
1241 
1242 static int __init fib_rules_init(void)
1243 {
1244         int err;
1245         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1246         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1247         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1248 
1249         err = register_pernet_subsys(&fib_rules_net_ops);
1250         if (err < 0)
1251                 goto fail;
1252 
1253         err = register_netdevice_notifier(&fib_rules_notifier);
1254         if (err < 0)
1255                 goto fail_unregister;
1256 
1257         return 0;
1258 
1259 fail_unregister:
1260         unregister_pernet_subsys(&fib_rules_net_ops);
1261 fail:
1262         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1263         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1264         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1265         return err;
1266 }
1267 
1268 subsys_initcall(fib_rules_init);
1269 

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