net/core/fib_rules.c

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