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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 <[email protected]>
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/inet_dscp.h>
15 #include <net/sock.h>
16 #include <net/fib_rules.h>
17 #include <net/ip_tunnels.h>
18 #include <linux/indirect_call_wrapper.h>
19
20 #if defined(CONFIG_IPV6) && defined(CONFIG_IPV6_MULTIPLE_TABLES)
21 #ifdef CONFIG_IP_MULTIPLE_TABLES
22 #define INDIRECT_CALL_MT(f, f2, f1, ...) \
23         INDIRECT_CALL_INET(f, f2, f1, __VA_ARGS__)
24 #else
25 #define INDIRECT_CALL_MT(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
26 #endif
27 #elif defined(CONFIG_IP_MULTIPLE_TABLES)
28 #define INDIRECT_CALL_MT(f, f2, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
29 #else
30 #define INDIRECT_CALL_MT(f, f2, f1, ...) f(__VA_ARGS__)
31 #endif
32
33 static const struct fib_kuid_range fib_kuid_range_unset = {
34         KUIDT_INIT(0),
35         KUIDT_INIT(~0),
36 };
37
38 bool fib_rule_matchall(const struct fib_rule *rule)
39 {
40         if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
41             rule->flags)
42                 return false;
43         if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
44                 return false;
45         if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
46             !uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
47                 return false;
48         if (fib_rule_port_range_set(&rule->sport_range))
49                 return false;
50         if (fib_rule_port_range_set(&rule->dport_range))
51                 return false;
52         return true;
53 }
54 EXPORT_SYMBOL_GPL(fib_rule_matchall);
55
56 int fib_default_rule_add(struct fib_rules_ops *ops,
57                          u32 pref, u32 table)
58 {
59         struct fib_rule *r;
60
61         r = kzalloc(ops->rule_size, GFP_KERNEL_ACCOUNT);
62         if (r == NULL)
63                 return -ENOMEM;
64
65         refcount_set(&r->refcnt, 1);
66         r->action = FR_ACT_TO_TBL;
67         r->pref = pref;
68         r->table = table;
69         r->proto = RTPROT_KERNEL;
70         r->fr_net = ops->fro_net;
71         r->uid_range = fib_kuid_range_unset;
72
73         r->suppress_prefixlen = -1;
74         r->suppress_ifgroup = -1;
75
76         /* The lock is not required here, the list in unreachable
77          * at the moment this function is called */
78         list_add_tail(&r->list, &ops->rules_list);
79         return 0;
80 }
81 EXPORT_SYMBOL(fib_default_rule_add);
82
83 static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
84 {
85         struct list_head *pos;
86         struct fib_rule *rule;
87
88         if (!list_empty(&ops->rules_list)) {
89                 pos = ops->rules_list.next;
90                 if (pos->next != &ops->rules_list) {
91                         rule = list_entry(pos->next, struct fib_rule, list);
92                         if (rule->pref)
93                                 return rule->pref - 1;
94                 }
95         }
96
97         return 0;
98 }
99
100 static void notify_rule_change(int event, struct fib_rule *rule,
101                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
102                                u32 pid);
103
104 static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
105 {
106         struct fib_rules_ops *ops;
107
108         rcu_read_lock();
109         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
110                 if (ops->family == family) {
111                         if (!try_module_get(ops->owner))
112                                 ops = NULL;
113                         rcu_read_unlock();
114                         return ops;
115                 }
116         }
117         rcu_read_unlock();
118
119         return NULL;
120 }
121
122 static void rules_ops_put(struct fib_rules_ops *ops)
123 {
124         if (ops)
125                 module_put(ops->owner);
126 }
127
128 static void flush_route_cache(struct fib_rules_ops *ops)
129 {
130         if (ops->flush_cache)
131                 ops->flush_cache(ops);
132 }
133
134 static int __fib_rules_register(struct fib_rules_ops *ops)
135 {
136         int err = -EEXIST;
137         struct fib_rules_ops *o;
138         struct net *net;
139
140         net = ops->fro_net;
141
142         if (ops->rule_size < sizeof(struct fib_rule))
143                 return -EINVAL;
144
145         if (ops->match == NULL || ops->configure == NULL ||
146             ops->compare == NULL || ops->fill == NULL ||
147             ops->action == NULL)
148                 return -EINVAL;
149
150         spin_lock(&net->rules_mod_lock);
151         list_for_each_entry(o, &net->rules_ops, list)
152                 if (ops->family == o->family)
153                         goto errout;
154
155         list_add_tail_rcu(&ops->list, &net->rules_ops);
156         err = 0;
157 errout:
158         spin_unlock(&net->rules_mod_lock);
159
160         return err;
161 }
162
163 struct fib_rules_ops *
164 fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
165 {
166         struct fib_rules_ops *ops;
167         int err;
168
169         ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
170         if (ops == NULL)
171                 return ERR_PTR(-ENOMEM);
172
173         INIT_LIST_HEAD(&ops->rules_list);
174         ops->fro_net = net;
175
176         err = __fib_rules_register(ops);
177         if (err) {
178                 kfree(ops);
179                 ops = ERR_PTR(err);
180         }
181
182         return ops;
183 }
184 EXPORT_SYMBOL_GPL(fib_rules_register);
185
186 static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
187 {
188         struct fib_rule *rule, *tmp;
189
190         list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
191                 list_del_rcu(&rule->list);
192                 if (ops->delete)
193                         ops->delete(rule);
194                 fib_rule_put(rule);
195         }
196 }
197
198 void fib_rules_unregister(struct fib_rules_ops *ops)
199 {
200         struct net *net = ops->fro_net;
201
202         spin_lock(&net->rules_mod_lock);
203         list_del_rcu(&ops->list);
204         spin_unlock(&net->rules_mod_lock);
205
206         fib_rules_cleanup_ops(ops);
207         kfree_rcu(ops, rcu);
208 }
209 EXPORT_SYMBOL_GPL(fib_rules_unregister);
210
211 static int uid_range_set(struct fib_kuid_range *range)
212 {
213         return uid_valid(range->start) && uid_valid(range->end);
214 }
215
216 static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
217 {
218         struct fib_rule_uid_range *in;
219         struct fib_kuid_range out;
220
221         in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
222
223         out.start = make_kuid(current_user_ns(), in->start);
224         out.end = make_kuid(current_user_ns(), in->end);
225
226         return out;
227 }
228
229 static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
230 {
231         struct fib_rule_uid_range out = {
232                 from_kuid_munged(current_user_ns(), range->start),
233                 from_kuid_munged(current_user_ns(), range->end)
234         };
235
236         return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
237 }
238
239 static int nla_get_port_range(struct nlattr *pattr,
240                               struct fib_rule_port_range *port_range)
241 {
242         const struct fib_rule_port_range *pr = nla_data(pattr);
243
244         if (!fib_rule_port_range_valid(pr))
245                 return -EINVAL;
246
247         port_range->start = pr->start;
248         port_range->end = pr->end;
249
250         return 0;
251 }
252
253 static int nla_put_port_range(struct sk_buff *skb, int attrtype,
254                               struct fib_rule_port_range *range)
255 {
256         return nla_put(skb, attrtype, sizeof(*range), range);
257 }
258
259 static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
260                           struct flowi *fl, int flags,
261                           struct fib_lookup_arg *arg)
262 {
263         int ret = 0;
264
265         if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
266                 goto out;
267
268         if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
269                 goto out;
270
271         if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
272                 goto out;
273
274         if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
275                 goto out;
276
277         if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
278                 goto out;
279
280         if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
281             uid_gt(fl->flowi_uid, rule->uid_range.end))
282                 goto out;
283
284         ret = INDIRECT_CALL_MT(ops->match,
285                                fib6_rule_match,
286                                fib4_rule_match,
287                                rule, fl, flags);
288 out:
289         return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
290 }
291
292 int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
293                      int flags, struct fib_lookup_arg *arg)
294 {
295         struct fib_rule *rule;
296         int err;
297
298         rcu_read_lock();
299
300         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
301 jumped:
302                 if (!fib_rule_match(rule, ops, fl, flags, arg))
303                         continue;
304
305                 if (rule->action == FR_ACT_GOTO) {
306                         struct fib_rule *target;
307
308                         target = rcu_dereference(rule->ctarget);
309                         if (target == NULL) {
310                                 continue;
311                         } else {
312                                 rule = target;
313                                 goto jumped;
314                         }
315                 } else if (rule->action == FR_ACT_NOP)
316                         continue;
317                 else
318                         err = INDIRECT_CALL_MT(ops->action,
319                                                fib6_rule_action,
320                                                fib4_rule_action,
321                                                rule, fl, flags, arg);
322
323                 if (!err && ops->suppress && INDIRECT_CALL_MT(ops->suppress,
324                                                               fib6_rule_suppress,
325                                                               fib4_rule_suppress,
326                                                               rule, flags, arg))
327                         continue;
328
329                 if (err != -EAGAIN) {
330                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
331                             likely(refcount_inc_not_zero(&rule->refcnt))) {
332                                 arg->rule = rule;
333                                 goto out;
334                         }
335                         break;
336                 }
337         }
338
339         err = -ESRCH;
340 out:
341         rcu_read_unlock();
342
343         return err;
344 }
345 EXPORT_SYMBOL_GPL(fib_rules_lookup);
346
347 static int call_fib_rule_notifier(struct notifier_block *nb,
348                                   enum fib_event_type event_type,
349                                   struct fib_rule *rule, int family,
350                                   struct netlink_ext_ack *extack)
351 {
352         struct fib_rule_notifier_info info = {
353                 .info.family = family,
354                 .info.extack = extack,
355                 .rule = rule,
356         };
357
358         return call_fib_notifier(nb, event_type, &info.info);
359 }
360
361 static int call_fib_rule_notifiers(struct net *net,
362                                    enum fib_event_type event_type,
363                                    struct fib_rule *rule,
364                                    struct fib_rules_ops *ops,
365                                    struct netlink_ext_ack *extack)
366 {
367         struct fib_rule_notifier_info info = {
368                 .info.family = ops->family,
369                 .info.extack = extack,
370                 .rule = rule,
371         };
372
373         ops->fib_rules_seq++;
374         return call_fib_notifiers(net, event_type, &info.info);
375 }
376
377 /* Called with rcu_read_lock() */
378 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family,
379                    struct netlink_ext_ack *extack)
380 {
381         struct fib_rules_ops *ops;
382         struct fib_rule *rule;
383         int err = 0;
384
385         ops = lookup_rules_ops(net, family);
386         if (!ops)
387                 return -EAFNOSUPPORT;
388         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
389                 err = call_fib_rule_notifier(nb, FIB_EVENT_RULE_ADD,
390                                              rule, family, extack);
391                 if (err)
392                         break;
393         }
394         rules_ops_put(ops);
395
396         return err;
397 }
398 EXPORT_SYMBOL_GPL(fib_rules_dump);
399
400 unsigned int fib_rules_seq_read(struct net *net, int family)
401 {
402         unsigned int fib_rules_seq;
403         struct fib_rules_ops *ops;
404
405         ASSERT_RTNL();
406
407         ops = lookup_rules_ops(net, family);
408         if (!ops)
409                 return 0;
410         fib_rules_seq = ops->fib_rules_seq;
411         rules_ops_put(ops);
412
413         return fib_rules_seq;
414 }
415 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
416
417 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
418                                   struct fib_rule_hdr *frh,
419                                   struct nlattr **tb,
420                                   struct fib_rule *rule,
421                                   bool user_priority)
422 {
423         struct fib_rule *r;
424
425         list_for_each_entry(r, &ops->rules_list, list) {
426                 if (rule->action && r->action != rule->action)
427                         continue;
428
429                 if (rule->table && r->table != rule->table)
430                         continue;
431
432                 if (user_priority && r->pref != rule->pref)
433                         continue;
434
435                 if (rule->iifname[0] &&
436                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
437                         continue;
438
439                 if (rule->oifname[0] &&
440                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
441                         continue;
442
443                 if (rule->mark && r->mark != rule->mark)
444                         continue;
445
446                 if (rule->suppress_ifgroup != -1 &&
447                     r->suppress_ifgroup != rule->suppress_ifgroup)
448                         continue;
449
450                 if (rule->suppress_prefixlen != -1 &&
451                     r->suppress_prefixlen != rule->suppress_prefixlen)
452                         continue;
453
454                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
455                         continue;
456
457                 if (rule->tun_id && r->tun_id != rule->tun_id)
458                         continue;
459
460                 if (r->fr_net != rule->fr_net)
461                         continue;
462
463                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
464                         continue;
465
466                 if (uid_range_set(&rule->uid_range) &&
467                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
468                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
469                         continue;
470
471                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
472                         continue;
473
474                 if (rule->proto && r->proto != rule->proto)
475                         continue;
476
477                 if (fib_rule_port_range_set(&rule->sport_range) &&
478                     !fib_rule_port_range_compare(&r->sport_range,
479                                                  &rule->sport_range))
480                         continue;
481
482                 if (fib_rule_port_range_set(&rule->dport_range) &&
483                     !fib_rule_port_range_compare(&r->dport_range,
484                                                  &rule->dport_range))
485                         continue;
486
487                 if (!ops->compare(r, frh, tb))
488                         continue;
489                 return r;
490         }
491
492         return NULL;
493 }
494
495 #ifdef CONFIG_NET_L3_MASTER_DEV
496 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
497                               struct netlink_ext_ack *extack)
498 {
499         nlrule->l3mdev = nla_get_u8(nla);
500         if (nlrule->l3mdev != 1) {
501                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
502                 return -1;
503         }
504
505         return 0;
506 }
507 #else
508 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
509                               struct netlink_ext_ack *extack)
510 {
511         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
512         return -1;
513 }
514 #endif
515
516 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
517                        struct netlink_ext_ack *extack,
518                        struct fib_rules_ops *ops,
519                        struct nlattr *tb[],
520                        struct fib_rule **rule,
521                        bool *user_priority)
522 {
523         struct net *net = sock_net(skb->sk);
524         struct fib_rule_hdr *frh = nlmsg_data(nlh);
525         struct fib_rule *nlrule = NULL;
526         int err = -EINVAL;
527
528         if (frh->src_len)
529                 if (!tb[FRA_SRC] ||
530                     frh->src_len > (ops->addr_size * 8) ||
531                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
532                         NL_SET_ERR_MSG(extack, "Invalid source address");
533                         goto errout;
534         }
535
536         if (frh->dst_len)
537                 if (!tb[FRA_DST] ||
538                     frh->dst_len > (ops->addr_size * 8) ||
539                     nla_len(tb[FRA_DST]) != ops->addr_size) {
540                         NL_SET_ERR_MSG(extack, "Invalid dst address");
541                         goto errout;
542         }
543
544         nlrule = kzalloc(ops->rule_size, GFP_KERNEL_ACCOUNT);
545         if (!nlrule) {
546                 err = -ENOMEM;
547                 goto errout;
548         }
549         refcount_set(&nlrule->refcnt, 1);
550         nlrule->fr_net = net;
551
552         if (tb[FRA_PRIORITY]) {
553                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
554                 *user_priority = true;
555         } else {
556                 nlrule->pref = fib_default_rule_pref(ops);
557         }
558
559         nlrule->proto = tb[FRA_PROTOCOL] ?
560                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
561
562         if (tb[FRA_IIFNAME]) {
563                 struct net_device *dev;
564
565                 nlrule->iifindex = -1;
566                 nla_strscpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
567                 dev = __dev_get_by_name(net, nlrule->iifname);
568                 if (dev)
569                         nlrule->iifindex = dev->ifindex;
570         }
571
572         if (tb[FRA_OIFNAME]) {
573                 struct net_device *dev;
574
575                 nlrule->oifindex = -1;
576                 nla_strscpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
577                 dev = __dev_get_by_name(net, nlrule->oifname);
578                 if (dev)
579                         nlrule->oifindex = dev->ifindex;
580         }
581
582         if (tb[FRA_FWMARK]) {
583                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
584                 if (nlrule->mark)
585                         /* compatibility: if the mark value is non-zero all bits
586                          * are compared unless a mask is explicitly specified.
587                          */
588                         nlrule->mark_mask = 0xFFFFFFFF;
589         }
590
591         if (tb[FRA_FWMASK])
592                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
593
594         if (tb[FRA_TUN_ID])
595                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
596
597         if (tb[FRA_L3MDEV] &&
598             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
599                 goto errout_free;
600
601         nlrule->action = frh->action;
602         nlrule->flags = frh->flags;
603         nlrule->table = frh_get_table(frh, tb);
604         if (tb[FRA_SUPPRESS_PREFIXLEN])
605                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
606         else
607                 nlrule->suppress_prefixlen = -1;
608
609         if (tb[FRA_SUPPRESS_IFGROUP])
610                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
611         else
612                 nlrule->suppress_ifgroup = -1;
613
614         if (tb[FRA_GOTO]) {
615                 if (nlrule->action != FR_ACT_GOTO) {
616                         NL_SET_ERR_MSG(extack, "Unexpected goto");
617                         goto errout_free;
618                 }
619
620                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
621                 /* Backward jumps are prohibited to avoid endless loops */
622                 if (nlrule->target <= nlrule->pref) {
623                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
624                         goto errout_free;
625                 }
626         } else if (nlrule->action == FR_ACT_GOTO) {
627                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
628                 goto errout_free;
629         }
630
631         if (nlrule->l3mdev && nlrule->table) {
632                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
633                 goto errout_free;
634         }
635
636         if (tb[FRA_UID_RANGE]) {
637                 if (current_user_ns() != net->user_ns) {
638                         err = -EPERM;
639                         NL_SET_ERR_MSG(extack, "No permission to set uid");
640                         goto errout_free;
641                 }
642
643                 nlrule->uid_range = nla_get_kuid_range(tb);
644
645                 if (!uid_range_set(&nlrule->uid_range) ||
646                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
647                         NL_SET_ERR_MSG(extack, "Invalid uid range");
648                         goto errout_free;
649                 }
650         } else {
651                 nlrule->uid_range = fib_kuid_range_unset;
652         }
653
654         if (tb[FRA_IP_PROTO])
655                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
656
657         if (tb[FRA_SPORT_RANGE]) {
658                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
659                                          &nlrule->sport_range);
660                 if (err) {
661                         NL_SET_ERR_MSG(extack, "Invalid sport range");
662                         goto errout_free;
663                 }
664         }
665
666         if (tb[FRA_DPORT_RANGE]) {
667                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
668                                          &nlrule->dport_range);
669                 if (err) {
670                         NL_SET_ERR_MSG(extack, "Invalid dport range");
671                         goto errout_free;
672                 }
673         }
674
675         *rule = nlrule;
676
677         return 0;
678
679 errout_free:
680         kfree(nlrule);
681 errout:
682         return err;
683 }
684
685 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
686                        struct nlattr **tb, struct fib_rule *rule)
687 {
688         struct fib_rule *r;
689
690         list_for_each_entry(r, &ops->rules_list, list) {
691                 if (r->action != rule->action)
692                         continue;
693
694                 if (r->table != rule->table)
695                         continue;
696
697                 if (r->pref != rule->pref)
698                         continue;
699
700                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
701                         continue;
702
703                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
704                         continue;
705
706                 if (r->mark != rule->mark)
707                         continue;
708
709                 if (r->suppress_ifgroup != rule->suppress_ifgroup)
710                         continue;
711
712                 if (r->suppress_prefixlen != rule->suppress_prefixlen)
713                         continue;
714
715                 if (r->mark_mask != rule->mark_mask)
716                         continue;
717
718                 if (r->tun_id != rule->tun_id)
719                         continue;
720
721                 if (r->fr_net != rule->fr_net)
722                         continue;
723
724                 if (r->l3mdev != rule->l3mdev)
725                         continue;
726
727                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
728                     !uid_eq(r->uid_range.end, rule->uid_range.end))
729                         continue;
730
731                 if (r->ip_proto != rule->ip_proto)
732                         continue;
733
734                 if (r->proto != rule->proto)
735                         continue;
736
737                 if (!fib_rule_port_range_compare(&r->sport_range,
738                                                  &rule->sport_range))
739                         continue;
740
741                 if (!fib_rule_port_range_compare(&r->dport_range,
742                                                  &rule->dport_range))
743                         continue;
744
745                 if (!ops->compare(r, frh, tb))
746                         continue;
747                 return 1;
748         }
749         return 0;
750 }
751
752 static const struct nla_policy fib_rule_policy[FRA_MAX + 1] = {
753         [FRA_UNSPEC]    = { .strict_start_type = FRA_DPORT_RANGE + 1 },
754         [FRA_IIFNAME]   = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
755         [FRA_OIFNAME]   = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
756         [FRA_PRIORITY]  = { .type = NLA_U32 },
757         [FRA_FWMARK]    = { .type = NLA_U32 },
758         [FRA_FLOW]      = { .type = NLA_U32 },
759         [FRA_TUN_ID]    = { .type = NLA_U64 },
760         [FRA_FWMASK]    = { .type = NLA_U32 },
761         [FRA_TABLE]     = { .type = NLA_U32 },
762         [FRA_SUPPRESS_PREFIXLEN] = { .type = NLA_U32 },
763         [FRA_SUPPRESS_IFGROUP] = { .type = NLA_U32 },
764         [FRA_GOTO]      = { .type = NLA_U32 },
765         [FRA_L3MDEV]    = { .type = NLA_U8 },
766         [FRA_UID_RANGE] = { .len = sizeof(struct fib_rule_uid_range) },
767         [FRA_PROTOCOL]  = { .type = NLA_U8 },
768         [FRA_IP_PROTO]  = { .type = NLA_U8 },
769         [FRA_SPORT_RANGE] = { .len = sizeof(struct fib_rule_port_range) },
770         [FRA_DPORT_RANGE] = { .len = sizeof(struct fib_rule_port_range) },
771         [FRA_DSCP]      = NLA_POLICY_MAX(NLA_U8, INET_DSCP_MASK >> 2),
772 };
773
774 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
775                    struct netlink_ext_ack *extack)
776 {
777         struct net *net = sock_net(skb->sk);
778         struct fib_rule_hdr *frh = nlmsg_data(nlh);
779         struct fib_rules_ops *ops = NULL;
780         struct fib_rule *rule = NULL, *r, *last = NULL;
781         struct nlattr *tb[FRA_MAX + 1];
782         int err = -EINVAL, unresolved = 0;
783         bool user_priority = false;
784
785         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
786                 NL_SET_ERR_MSG(extack, "Invalid msg length");
787                 goto errout;
788         }
789
790         ops = lookup_rules_ops(net, frh->family);
791         if (!ops) {
792                 err = -EAFNOSUPPORT;
793                 NL_SET_ERR_MSG(extack, "Rule family not supported");
794                 goto errout;
795         }
796
797         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
798                                      fib_rule_policy, extack);
799         if (err < 0) {
800                 NL_SET_ERR_MSG(extack, "Error parsing msg");
801                 goto errout;
802         }
803
804         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
805         if (err)
806                 goto errout;
807
808         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
809             rule_exists(ops, frh, tb, rule)) {
810                 err = -EEXIST;
811                 goto errout_free;
812         }
813
814         err = ops->configure(rule, skb, frh, tb, extack);
815         if (err < 0)
816                 goto errout_free;
817
818         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
819                                       extack);
820         if (err < 0)
821                 goto errout_free;
822
823         list_for_each_entry(r, &ops->rules_list, list) {
824                 if (r->pref == rule->target) {
825                         RCU_INIT_POINTER(rule->ctarget, r);
826                         break;
827                 }
828         }
829
830         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
831                 unresolved = 1;
832
833         list_for_each_entry(r, &ops->rules_list, list) {
834                 if (r->pref > rule->pref)
835                         break;
836                 last = r;
837         }
838
839         if (last)
840                 list_add_rcu(&rule->list, &last->list);
841         else
842                 list_add_rcu(&rule->list, &ops->rules_list);
843
844         if (ops->unresolved_rules) {
845                 /*
846                  * There are unresolved goto rules in the list, check if
847                  * any of them are pointing to this new rule.
848                  */
849                 list_for_each_entry(r, &ops->rules_list, list) {
850                         if (r->action == FR_ACT_GOTO &&
851                             r->target == rule->pref &&
852                             rtnl_dereference(r->ctarget) == NULL) {
853                                 rcu_assign_pointer(r->ctarget, rule);
854                                 if (--ops->unresolved_rules == 0)
855                                         break;
856                         }
857                 }
858         }
859
860         if (rule->action == FR_ACT_GOTO)
861                 ops->nr_goto_rules++;
862
863         if (unresolved)
864                 ops->unresolved_rules++;
865
866         if (rule->tun_id)
867                 ip_tunnel_need_metadata();
868
869         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
870         flush_route_cache(ops);
871         rules_ops_put(ops);
872         return 0;
873
874 errout_free:
875         kfree(rule);
876 errout:
877         rules_ops_put(ops);
878         return err;
879 }
880 EXPORT_SYMBOL_GPL(fib_nl_newrule);
881
882 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
883                    struct netlink_ext_ack *extack)
884 {
885         struct net *net = sock_net(skb->sk);
886         struct fib_rule_hdr *frh = nlmsg_data(nlh);
887         struct fib_rules_ops *ops = NULL;
888         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
889         struct nlattr *tb[FRA_MAX+1];
890         int err = -EINVAL;
891         bool user_priority = false;
892
893         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
894                 NL_SET_ERR_MSG(extack, "Invalid msg length");
895                 goto errout;
896         }
897
898         ops = lookup_rules_ops(net, frh->family);
899         if (ops == NULL) {
900                 err = -EAFNOSUPPORT;
901                 NL_SET_ERR_MSG(extack, "Rule family not supported");
902                 goto errout;
903         }
904
905         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
906                                      fib_rule_policy, extack);
907         if (err < 0) {
908                 NL_SET_ERR_MSG(extack, "Error parsing msg");
909                 goto errout;
910         }
911
912         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
913         if (err)
914                 goto errout;
915
916         rule = rule_find(ops, frh, tb, nlrule, user_priority);
917         if (!rule) {
918                 err = -ENOENT;
919                 goto errout;
920         }
921
922         if (rule->flags & FIB_RULE_PERMANENT) {
923                 err = -EPERM;
924                 goto errout;
925         }
926
927         if (ops->delete) {
928                 err = ops->delete(rule);
929                 if (err)
930                         goto errout;
931         }
932
933         if (rule->tun_id)
934                 ip_tunnel_unneed_metadata();
935
936         list_del_rcu(&rule->list);
937
938         if (rule->action == FR_ACT_GOTO) {
939                 ops->nr_goto_rules--;
940                 if (rtnl_dereference(rule->ctarget) == NULL)
941                         ops->unresolved_rules--;
942         }
943
944         /*
945          * Check if this rule is a target to any of them. If so,
946          * adjust to the next one with the same preference or
947          * disable them. As this operation is eventually very
948          * expensive, it is only performed if goto rules, except
949          * current if it is goto rule, have actually been added.
950          */
951         if (ops->nr_goto_rules > 0) {
952                 struct fib_rule *n;
953
954                 n = list_next_entry(rule, list);
955                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
956                         n = NULL;
957                 list_for_each_entry(r, &ops->rules_list, list) {
958                         if (rtnl_dereference(r->ctarget) != rule)
959                                 continue;
960                         rcu_assign_pointer(r->ctarget, n);
961                         if (!n)
962                                 ops->unresolved_rules++;
963                 }
964         }
965
966         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
967                                 NULL);
968         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
969                            NETLINK_CB(skb).portid);
970         fib_rule_put(rule);
971         flush_route_cache(ops);
972         rules_ops_put(ops);
973         kfree(nlrule);
974         return 0;
975
976 errout:
977         kfree(nlrule);
978         rules_ops_put(ops);
979         return err;
980 }
981 EXPORT_SYMBOL_GPL(fib_nl_delrule);
982
983 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
984                                          struct fib_rule *rule)
985 {
986         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
987                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
988                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
989                          + nla_total_size(4) /* FRA_PRIORITY */
990                          + nla_total_size(4) /* FRA_TABLE */
991                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
992                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
993                          + nla_total_size(4) /* FRA_FWMARK */
994                          + nla_total_size(4) /* FRA_FWMASK */
995                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
996                          + nla_total_size(sizeof(struct fib_kuid_range))
997                          + nla_total_size(1) /* FRA_PROTOCOL */
998                          + nla_total_size(1) /* FRA_IP_PROTO */
999                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
1000                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
1001
1002         if (ops->nlmsg_payload)
1003                 payload += ops->nlmsg_payload(rule);
1004
1005         return payload;
1006 }
1007
1008 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
1009                             u32 pid, u32 seq, int type, int flags,
1010                             struct fib_rules_ops *ops)
1011 {
1012         struct nlmsghdr *nlh;
1013         struct fib_rule_hdr *frh;
1014
1015         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
1016         if (nlh == NULL)
1017                 return -EMSGSIZE;
1018
1019         frh = nlmsg_data(nlh);
1020         frh->family = ops->family;
1021         frh->table = rule->table < 256 ? rule->table : RT_TABLE_COMPAT;
1022         if (nla_put_u32(skb, FRA_TABLE, rule->table))
1023                 goto nla_put_failure;
1024         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
1025                 goto nla_put_failure;
1026         frh->res1 = 0;
1027         frh->res2 = 0;
1028         frh->action = rule->action;
1029         frh->flags = rule->flags;
1030
1031         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
1032                 goto nla_put_failure;
1033
1034         if (rule->action == FR_ACT_GOTO &&
1035             rcu_access_pointer(rule->ctarget) == NULL)
1036                 frh->flags |= FIB_RULE_UNRESOLVED;
1037
1038         if (rule->iifname[0]) {
1039                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
1040                         goto nla_put_failure;
1041                 if (rule->iifindex == -1)
1042                         frh->flags |= FIB_RULE_IIF_DETACHED;
1043         }
1044
1045         if (rule->oifname[0]) {
1046                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
1047                         goto nla_put_failure;
1048                 if (rule->oifindex == -1)
1049                         frh->flags |= FIB_RULE_OIF_DETACHED;
1050         }
1051
1052         if ((rule->pref &&
1053              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
1054             (rule->mark &&
1055              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
1056             ((rule->mark_mask || rule->mark) &&
1057              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
1058             (rule->target &&
1059              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
1060             (rule->tun_id &&
1061              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
1062             (rule->l3mdev &&
1063              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
1064             (uid_range_set(&rule->uid_range) &&
1065              nla_put_uid_range(skb, &rule->uid_range)) ||
1066             (fib_rule_port_range_set(&rule->sport_range) &&
1067              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
1068             (fib_rule_port_range_set(&rule->dport_range) &&
1069              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
1070             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
1071                 goto nla_put_failure;
1072
1073         if (rule->suppress_ifgroup != -1) {
1074                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
1075                         goto nla_put_failure;
1076         }
1077
1078         if (ops->fill(rule, skb, frh) < 0)
1079                 goto nla_put_failure;
1080
1081         nlmsg_end(skb, nlh);
1082         return 0;
1083
1084 nla_put_failure:
1085         nlmsg_cancel(skb, nlh);
1086         return -EMSGSIZE;
1087 }
1088
1089 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
1090                       struct fib_rules_ops *ops)
1091 {
1092         int idx = 0;
1093         struct fib_rule *rule;
1094         int err = 0;
1095
1096         rcu_read_lock();
1097         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
1098                 if (idx < cb->args[1])
1099                         goto skip;
1100
1101                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
1102                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
1103                                        NLM_F_MULTI, ops);
1104                 if (err)
1105                         break;
1106 skip:
1107                 idx++;
1108         }
1109         rcu_read_unlock();
1110         cb->args[1] = idx;
1111         rules_ops_put(ops);
1112
1113         return err;
1114 }
1115
1116 static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
1117                                    struct netlink_ext_ack *extack)
1118 {
1119         struct fib_rule_hdr *frh;
1120
1121         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
1122                 NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
1123                 return -EINVAL;
1124         }
1125
1126         frh = nlmsg_data(nlh);
1127         if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
1128             frh->res1 || frh->res2 || frh->action || frh->flags) {
1129                 NL_SET_ERR_MSG(extack,
1130                                "Invalid values in header for fib rule dump request");
1131                 return -EINVAL;
1132         }
1133
1134         if (nlmsg_attrlen(nlh, sizeof(*frh))) {
1135                 NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
1136                 return -EINVAL;
1137         }
1138
1139         return 0;
1140 }
1141
1142 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
1143 {
1144         const struct nlmsghdr *nlh = cb->nlh;
1145         struct net *net = sock_net(skb->sk);
1146         struct fib_rules_ops *ops;
1147         int err, idx = 0, family;
1148
1149         if (cb->strict_check) {
1150                 err = fib_valid_dumprule_req(nlh, cb->extack);
1151
1152                 if (err < 0)
1153                         return err;
1154         }
1155
1156         family = rtnl_msg_family(nlh);
1157         if (family != AF_UNSPEC) {
1158                 /* Protocol specific dump request */
1159                 ops = lookup_rules_ops(net, family);
1160                 if (ops == NULL)
1161                         return -EAFNOSUPPORT;
1162
1163                 return dump_rules(skb, cb, ops);
1164         }
1165
1166         err = 0;
1167         rcu_read_lock();
1168         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1169                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1170                         goto skip;
1171
1172                 err = dump_rules(skb, cb, ops);
1173                 if (err < 0)
1174                         break;
1175
1176                 cb->args[1] = 0;
1177 skip:
1178                 idx++;
1179         }
1180         rcu_read_unlock();
1181         cb->args[0] = idx;
1182
1183         return err;
1184 }
1185
1186 static void notify_rule_change(int event, struct fib_rule *rule,
1187                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1188                                u32 pid)
1189 {
1190         struct net *net;
1191         struct sk_buff *skb;
1192         int err = -ENOMEM;
1193
1194         net = ops->fro_net;
1195         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1196         if (skb == NULL)
1197                 goto errout;
1198
1199         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1200         if (err < 0) {
1201                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1202                 WARN_ON(err == -EMSGSIZE);
1203                 kfree_skb(skb);
1204                 goto errout;
1205         }
1206
1207         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1208         return;
1209 errout:
1210         rtnl_set_sk_err(net, ops->nlgroup, err);
1211 }
1212
1213 static void attach_rules(struct list_head *rules, struct net_device *dev)
1214 {
1215         struct fib_rule *rule;
1216
1217         list_for_each_entry(rule, rules, list) {
1218                 if (rule->iifindex == -1 &&
1219                     strcmp(dev->name, rule->iifname) == 0)
1220                         rule->iifindex = dev->ifindex;
1221                 if (rule->oifindex == -1 &&
1222                     strcmp(dev->name, rule->oifname) == 0)
1223                         rule->oifindex = dev->ifindex;
1224         }
1225 }
1226
1227 static void detach_rules(struct list_head *rules, struct net_device *dev)
1228 {
1229         struct fib_rule *rule;
1230
1231         list_for_each_entry(rule, rules, list) {
1232                 if (rule->iifindex == dev->ifindex)
1233                         rule->iifindex = -1;
1234                 if (rule->oifindex == dev->ifindex)
1235                         rule->oifindex = -1;
1236         }
1237 }
1238
1239
1240 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1241                            void *ptr)
1242 {
1243         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1244         struct net *net = dev_net(dev);
1245         struct fib_rules_ops *ops;
1246
1247         ASSERT_RTNL();
1248
1249         switch (event) {
1250         case NETDEV_REGISTER:
1251                 list_for_each_entry(ops, &net->rules_ops, list)
1252                         attach_rules(&ops->rules_list, dev);
1253                 break;
1254
1255         case NETDEV_CHANGENAME:
1256                 list_for_each_entry(ops, &net->rules_ops, list) {
1257                         detach_rules(&ops->rules_list, dev);
1258                         attach_rules(&ops->rules_list, dev);
1259                 }
1260                 break;
1261
1262         case NETDEV_UNREGISTER:
1263                 list_for_each_entry(ops, &net->rules_ops, list)
1264                         detach_rules(&ops->rules_list, dev);
1265                 break;
1266         }
1267
1268         return NOTIFY_DONE;
1269 }
1270
1271 static struct notifier_block fib_rules_notifier = {
1272         .notifier_call = fib_rules_event,
1273 };
1274
1275 static int __net_init fib_rules_net_init(struct net *net)
1276 {
1277         INIT_LIST_HEAD(&net->rules_ops);
1278         spin_lock_init(&net->rules_mod_lock);
1279         return 0;
1280 }
1281
1282 static void __net_exit fib_rules_net_exit(struct net *net)
1283 {
1284         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1285 }
1286
1287 static struct pernet_operations fib_rules_net_ops = {
1288         .init = fib_rules_net_init,
1289         .exit = fib_rules_net_exit,
1290 };
1291
1292 static int __init fib_rules_init(void)
1293 {
1294         int err;
1295         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1296         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1297         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule,
1298                       RTNL_FLAG_DUMP_UNLOCKED);
1299
1300         err = register_pernet_subsys(&fib_rules_net_ops);
1301         if (err < 0)
1302                 goto fail;
1303
1304         err = register_netdevice_notifier(&fib_rules_notifier);
1305         if (err < 0)
1306                 goto fail_unregister;
1307
1308         return 0;
1309
1310 fail_unregister:
1311         unregister_pernet_subsys(&fib_rules_net_ops);
1312 fail:
1313         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1314         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1315         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1316         return err;
1317 }
1318
1319 subsys_initcall(fib_rules_init);
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