net/core/fib_rules.c

   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,
 325                                   enum fib_event_type event_type,
 326                                   struct fib_rule *rule, int family,
 327                                   struct netlink_ext_ack *extack)
 328 {
 329         struct fib_rule_notifier_info info = {
 330                 .info.family = family,
 331                 .info.extack = extack,
 332                 .rule = rule,
 333         };
 334
 335         return call_fib_notifier(nb, event_type, &info.info);
 336 }
 337
 338 static int call_fib_rule_notifiers(struct net *net,
 339                                    enum fib_event_type event_type,
 340                                    struct fib_rule *rule,
 341                                    struct fib_rules_ops *ops,
 342                                    struct netlink_ext_ack *extack)
 343 {
 344         struct fib_rule_notifier_info info = {
 345                 .info.family = ops->family,
 346                 .info.extack = extack,
 347                 .rule = rule,
 348         };
 349
 350         ops->fib_rules_seq++;
 351         return call_fib_notifiers(net, event_type, &info.info);
 352 }
 353
 354 /* Called with rcu_read_lock() */
 355 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family,
 356                    struct netlink_ext_ack *extack)
 357 {
 358         struct fib_rules_ops *ops;
 359         struct fib_rule *rule;
 360         int err = 0;
 361
 362         ops = lookup_rules_ops(net, family);
 363         if (!ops)
 364                 return -EAFNOSUPPORT;
 365         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
 366                 err = call_fib_rule_notifier(nb, FIB_EVENT_RULE_ADD,
 367                                              rule, family, extack);
 368                 if (err)
 369                         break;
 370         }
 371         rules_ops_put(ops);
 372
 373         return err;
 374 }
 375 EXPORT_SYMBOL_GPL(fib_rules_dump);
 376
 377 unsigned int fib_rules_seq_read(struct net *net, int family)
 378 {
 379         unsigned int fib_rules_seq;
 380         struct fib_rules_ops *ops;
 381
 382         ASSERT_RTNL();
 383
 384         ops = lookup_rules_ops(net, family);
 385         if (!ops)
 386                 return 0;
 387         fib_rules_seq = ops->fib_rules_seq;
 388         rules_ops_put(ops);
 389
 390         return fib_rules_seq;
 391 }
 392 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 393
 394 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
 395                                   struct fib_rule_hdr *frh,
 396                                   struct nlattr **tb,
 397                                   struct fib_rule *rule,
 398                                   bool user_priority)
 399 {
 400         struct fib_rule *r;
 401
 402         list_for_each_entry(r, &ops->rules_list, list) {
 403                 if (rule->action && r->action != rule->action)
 404                         continue;
 405
 406                 if (rule->table && r->table != rule->table)
 407                         continue;
 408
 409                 if (user_priority && r->pref != rule->pref)
 410                         continue;
 411
 412                 if (rule->iifname[0] &&
 413                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 414                         continue;
 415
 416                 if (rule->oifname[0] &&
 417                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 418                         continue;
 419
 420                 if (rule->mark && r->mark != rule->mark)
 421                         continue;
 422
 423                 if (rule->suppress_ifgroup != -1 &&
 424                     r->suppress_ifgroup != rule->suppress_ifgroup)
 425                         continue;
 426
 427                 if (rule->suppress_prefixlen != -1 &&
 428                     r->suppress_prefixlen != rule->suppress_prefixlen)
 429                         continue;
 430
 431                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
 432                         continue;
 433
 434                 if (rule->tun_id && r->tun_id != rule->tun_id)
 435                         continue;
 436
 437                 if (r->fr_net != rule->fr_net)
 438                         continue;
 439
 440                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
 441                         continue;
 442
 443                 if (uid_range_set(&rule->uid_range) &&
 444                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 445                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
 446                         continue;
 447
 448                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
 449                         continue;
 450
 451                 if (rule->proto && r->proto != rule->proto)
 452                         continue;
 453
 454                 if (fib_rule_port_range_set(&rule->sport_range) &&
 455                     !fib_rule_port_range_compare(&r->sport_range,
 456                                                  &rule->sport_range))
 457                         continue;
 458
 459                 if (fib_rule_port_range_set(&rule->dport_range) &&
 460                     !fib_rule_port_range_compare(&r->dport_range,
 461                                                  &rule->dport_range))
 462                         continue;
 463
 464                 if (!ops->compare(r, frh, tb))
 465                         continue;
 466                 return r;
 467         }
 468
 469         return NULL;
 470 }
 471
 472 #ifdef CONFIG_NET_L3_MASTER_DEV
 473 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 474                               struct netlink_ext_ack *extack)
 475 {
 476         nlrule->l3mdev = nla_get_u8(nla);
 477         if (nlrule->l3mdev != 1) {
 478                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
 479                 return -1;
 480         }
 481
 482         return 0;
 483 }
 484 #else
 485 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 486                               struct netlink_ext_ack *extack)
 487 {
 488         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
 489         return -1;
 490 }
 491 #endif
 492
 493 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
 494                        struct netlink_ext_ack *extack,
 495                        struct fib_rules_ops *ops,
 496                        struct nlattr *tb[],
 497                        struct fib_rule **rule,
 498                        bool *user_priority)
 499 {
 500         struct net *net = sock_net(skb->sk);
 501         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 502         struct fib_rule *nlrule = NULL;
 503         int err = -EINVAL;
 504
 505         if (frh->src_len)
 506                 if (!tb[FRA_SRC] ||
 507                     frh->src_len > (ops->addr_size * 8) ||
 508                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
 509                         NL_SET_ERR_MSG(extack, "Invalid source address");
 510                         goto errout;
 511         }
 512
 513         if (frh->dst_len)
 514                 if (!tb[FRA_DST] ||
 515                     frh->dst_len > (ops->addr_size * 8) ||
 516                     nla_len(tb[FRA_DST]) != ops->addr_size) {
 517                         NL_SET_ERR_MSG(extack, "Invalid dst address");
 518                         goto errout;
 519         }
 520
 521         nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
 522         if (!nlrule) {
 523                 err = -ENOMEM;
 524                 goto errout;
 525         }
 526         refcount_set(&nlrule->refcnt, 1);
 527         nlrule->fr_net = net;
 528
 529         if (tb[FRA_PRIORITY]) {
 530                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 531                 *user_priority = true;
 532         } else {
 533                 nlrule->pref = fib_default_rule_pref(ops);
 534         }
 535
 536         nlrule->proto = tb[FRA_PROTOCOL] ?
 537                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
 538
 539         if (tb[FRA_IIFNAME]) {
 540                 struct net_device *dev;
 541
 542                 nlrule->iifindex = -1;
 543                 nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 544                 dev = __dev_get_by_name(net, nlrule->iifname);
 545                 if (dev)
 546                         nlrule->iifindex = dev->ifindex;
 547         }
 548
 549         if (tb[FRA_OIFNAME]) {
 550                 struct net_device *dev;
 551
 552                 nlrule->oifindex = -1;
 553                 nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 554                 dev = __dev_get_by_name(net, nlrule->oifname);
 555                 if (dev)
 556                         nlrule->oifindex = dev->ifindex;
 557         }
 558
 559         if (tb[FRA_FWMARK]) {
 560                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
 561                 if (nlrule->mark)
 562                         /* compatibility: if the mark value is non-zero all bits
 563                          * are compared unless a mask is explicitly specified.
 564                          */
 565                         nlrule->mark_mask = 0xFFFFFFFF;
 566         }
 567
 568         if (tb[FRA_FWMASK])
 569                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 570
 571         if (tb[FRA_TUN_ID])
 572                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 573
 574         err = -EINVAL;
 575         if (tb[FRA_L3MDEV] &&
 576             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
 577                 goto errout_free;
 578
 579         nlrule->action = frh->action;
 580         nlrule->flags = frh->flags;
 581         nlrule->table = frh_get_table(frh, tb);
 582         if (tb[FRA_SUPPRESS_PREFIXLEN])
 583                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 584         else
 585                 nlrule->suppress_prefixlen = -1;
 586
 587         if (tb[FRA_SUPPRESS_IFGROUP])
 588                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 589         else
 590                 nlrule->suppress_ifgroup = -1;
 591
 592         if (tb[FRA_GOTO]) {
 593                 if (nlrule->action != FR_ACT_GOTO) {
 594                         NL_SET_ERR_MSG(extack, "Unexpected goto");
 595                         goto errout_free;
 596                 }
 597
 598                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
 599                 /* Backward jumps are prohibited to avoid endless loops */
 600                 if (nlrule->target <= nlrule->pref) {
 601                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
 602                         goto errout_free;
 603                 }
 604         } else if (nlrule->action == FR_ACT_GOTO) {
 605                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
 606                 goto errout_free;
 607         }
 608
 609         if (nlrule->l3mdev && nlrule->table) {
 610                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
 611                 goto errout_free;
 612         }
 613
 614         if (tb[FRA_UID_RANGE]) {
 615                 if (current_user_ns() != net->user_ns) {
 616                         err = -EPERM;
 617                         NL_SET_ERR_MSG(extack, "No permission to set uid");
 618                         goto errout_free;
 619                 }
 620
 621                 nlrule->uid_range = nla_get_kuid_range(tb);
 622
 623                 if (!uid_range_set(&nlrule->uid_range) ||
 624                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
 625                         NL_SET_ERR_MSG(extack, "Invalid uid range");
 626                         goto errout_free;
 627                 }
 628         } else {
 629                 nlrule->uid_range = fib_kuid_range_unset;
 630         }
 631
 632         if (tb[FRA_IP_PROTO])
 633                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
 634
 635         if (tb[FRA_SPORT_RANGE]) {
 636                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
 637                                          &nlrule->sport_range);
 638                 if (err) {
 639                         NL_SET_ERR_MSG(extack, "Invalid sport range");
 640                         goto errout_free;
 641                 }
 642         }
 643
 644         if (tb[FRA_DPORT_RANGE]) {
 645                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
 646                                          &nlrule->dport_range);
 647                 if (err) {
 648                         NL_SET_ERR_MSG(extack, "Invalid dport range");
 649                         goto errout_free;
 650                 }
 651         }
 652
 653         *rule = nlrule;
 654
 655         return 0;
 656
 657 errout_free:
 658         kfree(nlrule);
 659 errout:
 660         return err;
 661 }
 662
 663 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 664                        struct nlattr **tb, struct fib_rule *rule)
 665 {
 666         struct fib_rule *r;
 667
 668         list_for_each_entry(r, &ops->rules_list, list) {
 669                 if (r->action != rule->action)
 670                         continue;
 671
 672                 if (r->table != rule->table)
 673                         continue;
 674
 675                 if (r->pref != rule->pref)
 676                         continue;
 677
 678                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 679                         continue;
 680
 681                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 682                         continue;
 683
 684                 if (r->mark != rule->mark)
 685                         continue;
 686
 687                 if (r->suppress_ifgroup != rule->suppress_ifgroup)
 688                         continue;
 689
 690                 if (r->suppress_prefixlen != rule->suppress_prefixlen)
 691                         continue;
 692
 693                 if (r->mark_mask != rule->mark_mask)
 694                         continue;
 695
 696                 if (r->tun_id != rule->tun_id)
 697                         continue;
 698
 699                 if (r->fr_net != rule->fr_net)
 700                         continue;
 701
 702                 if (r->l3mdev != rule->l3mdev)
 703                         continue;
 704
 705                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 706                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 707                         continue;
 708
 709                 if (r->ip_proto != rule->ip_proto)
 710                         continue;
 711
 712                 if (r->proto != rule->proto)
 713                         continue;
 714
 715                 if (!fib_rule_port_range_compare(&r->sport_range,
 716                                                  &rule->sport_range))
 717                         continue;
 718
 719                 if (!fib_rule_port_range_compare(&r->dport_range,
 720                                                  &rule->dport_range))
 721                         continue;
 722
 723                 if (!ops->compare(r, frh, tb))
 724                         continue;
 725                 return 1;
 726         }
 727         return 0;
 728 }
 729
 730 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 731                    struct netlink_ext_ack *extack)
 732 {
 733         struct net *net = sock_net(skb->sk);
 734         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 735         struct fib_rules_ops *ops = NULL;
 736         struct fib_rule *rule = NULL, *r, *last = NULL;
 737         struct nlattr *tb[FRA_MAX + 1];
 738         int err = -EINVAL, unresolved = 0;
 739         bool user_priority = false;
 740
 741         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 742                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 743                 goto errout;
 744         }
 745
 746         ops = lookup_rules_ops(net, frh->family);
 747         if (!ops) {
 748                 err = -EAFNOSUPPORT;
 749                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 750                 goto errout;
 751         }
 752
 753         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
 754                                      ops->policy, extack);
 755         if (err < 0) {
 756                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 757                 goto errout;
 758         }
 759
 760         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
 761         if (err)
 762                 goto errout;
 763
 764         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 765             rule_exists(ops, frh, tb, rule)) {
 766                 err = -EEXIST;
 767                 goto errout_free;
 768         }
 769
 770         err = ops->configure(rule, skb, frh, tb, extack);
 771         if (err < 0)
 772                 goto errout_free;
 773
 774         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
 775                                       extack);
 776         if (err < 0)
 777                 goto errout_free;
 778
 779         list_for_each_entry(r, &ops->rules_list, list) {
 780                 if (r->pref == rule->target) {
 781                         RCU_INIT_POINTER(rule->ctarget, r);
 782                         break;
 783                 }
 784         }
 785
 786         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 787                 unresolved = 1;
 788
 789         list_for_each_entry(r, &ops->rules_list, list) {
 790                 if (r->pref > rule->pref)
 791                         break;
 792                 last = r;
 793         }
 794
 795         if (last)
 796                 list_add_rcu(&rule->list, &last->list);
 797         else
 798                 list_add_rcu(&rule->list, &ops->rules_list);
 799
 800         if (ops->unresolved_rules) {
 801                 /*
 802                  * There are unresolved goto rules in the list, check if
 803                  * any of them are pointing to this new rule.
 804                  */
 805                 list_for_each_entry(r, &ops->rules_list, list) {
 806                         if (r->action == FR_ACT_GOTO &&
 807                             r->target == rule->pref &&
 808                             rtnl_dereference(r->ctarget) == NULL) {
 809                                 rcu_assign_pointer(r->ctarget, rule);
 810                                 if (--ops->unresolved_rules == 0)
 811                                         break;
 812                         }
 813                 }
 814         }
 815
 816         if (rule->action == FR_ACT_GOTO)
 817                 ops->nr_goto_rules++;
 818
 819         if (unresolved)
 820                 ops->unresolved_rules++;
 821
 822         if (rule->tun_id)
 823                 ip_tunnel_need_metadata();
 824
 825         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 826         flush_route_cache(ops);
 827         rules_ops_put(ops);
 828         return 0;
 829
 830 errout_free:
 831         kfree(rule);
 832 errout:
 833         rules_ops_put(ops);
 834         return err;
 835 }
 836 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 837
 838 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 839                    struct netlink_ext_ack *extack)
 840 {
 841         struct net *net = sock_net(skb->sk);
 842         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 843         struct fib_rules_ops *ops = NULL;
 844         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
 845         struct nlattr *tb[FRA_MAX+1];
 846         int err = -EINVAL;
 847         bool user_priority = false;
 848
 849         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 850                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 851                 goto errout;
 852         }
 853
 854         ops = lookup_rules_ops(net, frh->family);
 855         if (ops == NULL) {
 856                 err = -EAFNOSUPPORT;
 857                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 858                 goto errout;
 859         }
 860
 861         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
 862                                      ops->policy, extack);
 863         if (err < 0) {
 864                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 865                 goto errout;
 866         }
 867
 868         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
 869         if (err)
 870                 goto errout;
 871
 872         rule = rule_find(ops, frh, tb, nlrule, user_priority);
 873         if (!rule) {
 874                 err = -ENOENT;
 875                 goto errout;
 876         }
 877
 878         if (rule->flags & FIB_RULE_PERMANENT) {
 879                 err = -EPERM;
 880                 goto errout;
 881         }
 882
 883         if (ops->delete) {
 884                 err = ops->delete(rule);
 885                 if (err)
 886                         goto errout;
 887         }
 888
 889         if (rule->tun_id)
 890                 ip_tunnel_unneed_metadata();
 891
 892         list_del_rcu(&rule->list);
 893
 894         if (rule->action == FR_ACT_GOTO) {
 895                 ops->nr_goto_rules--;
 896                 if (rtnl_dereference(rule->ctarget) == NULL)
 897                         ops->unresolved_rules--;
 898         }
 899
 900         /*
 901          * Check if this rule is a target to any of them. If so,
 902          * adjust to the next one with the same preference or
 903          * disable them. As this operation is eventually very
 904          * expensive, it is only performed if goto rules, except
 905          * current if it is goto rule, have actually been added.
 906          */
 907         if (ops->nr_goto_rules > 0) {
 908                 struct fib_rule *n;
 909
 910                 n = list_next_entry(rule, list);
 911                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
 912                         n = NULL;
 913                 list_for_each_entry(r, &ops->rules_list, list) {
 914                         if (rtnl_dereference(r->ctarget) != rule)
 915                                 continue;
 916                         rcu_assign_pointer(r->ctarget, n);
 917                         if (!n)
 918                                 ops->unresolved_rules++;
 919                 }
 920         }
 921
 922         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
 923                                 NULL);
 924         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 925                            NETLINK_CB(skb).portid);
 926         fib_rule_put(rule);
 927         flush_route_cache(ops);
 928         rules_ops_put(ops);
 929         kfree(nlrule);
 930         return 0;
 931
 932 errout:
 933         kfree(nlrule);
 934         rules_ops_put(ops);
 935         return err;
 936 }
 937 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 938
 939 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 940                                          struct fib_rule *rule)
 941 {
 942         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 943                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 944                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 945                          + nla_total_size(4) /* FRA_PRIORITY */
 946                          + nla_total_size(4) /* FRA_TABLE */
 947                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 948                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 949                          + nla_total_size(4) /* FRA_FWMARK */
 950                          + nla_total_size(4) /* FRA_FWMASK */
 951                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 952                          + nla_total_size(sizeof(struct fib_kuid_range))
 953                          + nla_total_size(1) /* FRA_PROTOCOL */
 954                          + nla_total_size(1) /* FRA_IP_PROTO */
 955                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
 956                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
 957
 958         if (ops->nlmsg_payload)
 959                 payload += ops->nlmsg_payload(rule);
 960
 961         return payload;
 962 }
 963
 964 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 965                             u32 pid, u32 seq, int type, int flags,
 966                             struct fib_rules_ops *ops)
 967 {
 968         struct nlmsghdr *nlh;
 969         struct fib_rule_hdr *frh;
 970
 971         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 972         if (nlh == NULL)
 973                 return -EMSGSIZE;
 974
 975         frh = nlmsg_data(nlh);
 976         frh->family = ops->family;
 977         frh->table = rule->table < 256 ? rule->table : RT_TABLE_COMPAT;
 978         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 979                 goto nla_put_failure;
 980         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 981                 goto nla_put_failure;
 982         frh->res1 = 0;
 983         frh->res2 = 0;
 984         frh->action = rule->action;
 985         frh->flags = rule->flags;
 986
 987         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
 988                 goto nla_put_failure;
 989
 990         if (rule->action == FR_ACT_GOTO &&
 991             rcu_access_pointer(rule->ctarget) == NULL)
 992                 frh->flags |= FIB_RULE_UNRESOLVED;
 993
 994         if (rule->iifname[0]) {
 995                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 996                         goto nla_put_failure;
 997                 if (rule->iifindex == -1)
 998                         frh->flags |= FIB_RULE_IIF_DETACHED;
 999         }
1000
1001         if (rule->oifname[0]) {
1002                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
1003                         goto nla_put_failure;
1004                 if (rule->oifindex == -1)
1005                         frh->flags |= FIB_RULE_OIF_DETACHED;
1006         }
1007
1008         if ((rule->pref &&
1009              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
1010             (rule->mark &&
1011              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
1012             ((rule->mark_mask || rule->mark) &&
1013              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
1014             (rule->target &&
1015              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
1016             (rule->tun_id &&
1017              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
1018             (rule->l3mdev &&
1019              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
1020             (uid_range_set(&rule->uid_range) &&
1021              nla_put_uid_range(skb, &rule->uid_range)) ||
1022             (fib_rule_port_range_set(&rule->sport_range) &&
1023              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
1024             (fib_rule_port_range_set(&rule->dport_range) &&
1025              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
1026             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
1027                 goto nla_put_failure;
1028
1029         if (rule->suppress_ifgroup != -1) {
1030                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
1031                         goto nla_put_failure;
1032         }
1033
1034         if (ops->fill(rule, skb, frh) < 0)
1035                 goto nla_put_failure;
1036
1037         nlmsg_end(skb, nlh);
1038         return 0;
1039
1040 nla_put_failure:
1041         nlmsg_cancel(skb, nlh);
1042         return -EMSGSIZE;
1043 }
1044
1045 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
1046                       struct fib_rules_ops *ops)
1047 {
1048         int idx = 0;
1049         struct fib_rule *rule;
1050         int err = 0;
1051
1052         rcu_read_lock();
1053         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
1054                 if (idx < cb->args[1])
1055                         goto skip;
1056
1057                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
1058                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
1059                                        NLM_F_MULTI, ops);
1060                 if (err)
1061                         break;
1062 skip:
1063                 idx++;
1064         }
1065         rcu_read_unlock();
1066         cb->args[1] = idx;
1067         rules_ops_put(ops);
1068
1069         return err;
1070 }
1071
1072 static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
1073                                    struct netlink_ext_ack *extack)
1074 {
1075         struct fib_rule_hdr *frh;
1076
1077         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
1078                 NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
1079                 return -EINVAL;
1080         }
1081
1082         frh = nlmsg_data(nlh);
1083         if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
1084             frh->res1 || frh->res2 || frh->action || frh->flags) {
1085                 NL_SET_ERR_MSG(extack,
1086                                "Invalid values in header for fib rule dump request");
1087                 return -EINVAL;
1088         }
1089
1090         if (nlmsg_attrlen(nlh, sizeof(*frh))) {
1091                 NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
1092                 return -EINVAL;
1093         }
1094
1095         return 0;
1096 }
1097
1098 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
1099 {
1100         const struct nlmsghdr *nlh = cb->nlh;
1101         struct net *net = sock_net(skb->sk);
1102         struct fib_rules_ops *ops;
1103         int idx = 0, family;
1104
1105         if (cb->strict_check) {
1106                 int err = fib_valid_dumprule_req(nlh, cb->extack);
1107
1108                 if (err < 0)
1109                         return err;
1110         }
1111
1112         family = rtnl_msg_family(nlh);
1113         if (family != AF_UNSPEC) {
1114                 /* Protocol specific dump request */
1115                 ops = lookup_rules_ops(net, family);
1116                 if (ops == NULL)
1117                         return -EAFNOSUPPORT;
1118
1119                 dump_rules(skb, cb, ops);
1120
1121                 return skb->len;
1122         }
1123
1124         rcu_read_lock();
1125         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1126                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1127                         goto skip;
1128
1129                 if (dump_rules(skb, cb, ops) < 0)
1130                         break;
1131
1132                 cb->args[1] = 0;
1133 skip:
1134                 idx++;
1135         }
1136         rcu_read_unlock();
1137         cb->args[0] = idx;
1138
1139         return skb->len;
1140 }
1141
1142 static void notify_rule_change(int event, struct fib_rule *rule,
1143                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1144                                u32 pid)
1145 {
1146         struct net *net;
1147         struct sk_buff *skb;
1148         int err = -ENOBUFS;
1149
1150         net = ops->fro_net;
1151         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1152         if (skb == NULL)
1153                 goto errout;
1154
1155         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1156         if (err < 0) {
1157                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1158                 WARN_ON(err == -EMSGSIZE);
1159                 kfree_skb(skb);
1160                 goto errout;
1161         }
1162
1163         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1164         return;
1165 errout:
1166         if (err < 0)
1167                 rtnl_set_sk_err(net, ops->nlgroup, err);
1168 }
1169
1170 static void attach_rules(struct list_head *rules, struct net_device *dev)
1171 {
1172         struct fib_rule *rule;
1173
1174         list_for_each_entry(rule, rules, list) {
1175                 if (rule->iifindex == -1 &&
1176                     strcmp(dev->name, rule->iifname) == 0)
1177                         rule->iifindex = dev->ifindex;
1178                 if (rule->oifindex == -1 &&
1179                     strcmp(dev->name, rule->oifname) == 0)
1180                         rule->oifindex = dev->ifindex;
1181         }
1182 }
1183
1184 static void detach_rules(struct list_head *rules, struct net_device *dev)
1185 {
1186         struct fib_rule *rule;
1187
1188         list_for_each_entry(rule, rules, list) {
1189                 if (rule->iifindex == dev->ifindex)
1190                         rule->iifindex = -1;
1191                 if (rule->oifindex == dev->ifindex)
1192                         rule->oifindex = -1;
1193         }
1194 }
1195
1196
1197 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1198                            void *ptr)
1199 {
1200         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1201         struct net *net = dev_net(dev);
1202         struct fib_rules_ops *ops;
1203
1204         ASSERT_RTNL();
1205
1206         switch (event) {
1207         case NETDEV_REGISTER:
1208                 list_for_each_entry(ops, &net->rules_ops, list)
1209                         attach_rules(&ops->rules_list, dev);
1210                 break;
1211
1212         case NETDEV_CHANGENAME:
1213                 list_for_each_entry(ops, &net->rules_ops, list) {
1214                         detach_rules(&ops->rules_list, dev);
1215                         attach_rules(&ops->rules_list, dev);
1216                 }
1217                 break;
1218
1219         case NETDEV_UNREGISTER:
1220                 list_for_each_entry(ops, &net->rules_ops, list)
1221                         detach_rules(&ops->rules_list, dev);
1222                 break;
1223         }
1224
1225         return NOTIFY_DONE;
1226 }
1227
1228 static struct notifier_block fib_rules_notifier = {
1229         .notifier_call = fib_rules_event,
1230 };
1231
1232 static int __net_init fib_rules_net_init(struct net *net)
1233 {
1234         INIT_LIST_HEAD(&net->rules_ops);
1235         spin_lock_init(&net->rules_mod_lock);
1236         return 0;
1237 }
1238
1239 static void __net_exit fib_rules_net_exit(struct net *net)
1240 {
1241         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1242 }
1243
1244 static struct pernet_operations fib_rules_net_ops = {
1245         .init = fib_rules_net_init,
1246         .exit = fib_rules_net_exit,
1247 };
1248
1249 static int __init fib_rules_init(void)
1250 {
1251         int err;
1252         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1253         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1254         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1255
1256         err = register_pernet_subsys(&fib_rules_net_ops);
1257         if (err < 0)
1258                 goto fail;
1259
1260         err = register_netdevice_notifier(&fib_rules_notifier);
1261         if (err < 0)
1262                 goto fail_unregister;
1263
1264         return 0;
1265
1266 fail_unregister:
1267         unregister_pernet_subsys(&fib_rules_net_ops);
1268 fail:
1269         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1270         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1271         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1272         return err;
1273 }
1274
1275 subsys_initcall(fib_rules_init);