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, flags, arg))
 304                         continue;
 305
 306                 if (err != -EAGAIN) {
 307                         if ((arg->flags & FIB_LOOKUP_NOREF) ||
 308                             likely(refcount_inc_not_zero(&rule->refcnt))) {
 309                                 arg->rule = rule;
 310                                 goto out;
 311                         }
 312                         break;
 313                 }
 314         }
 315
 316         err = -ESRCH;
 317 out:
 318         rcu_read_unlock();
 319
 320         return err;
 321 }
 322 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 323
 324 static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
 325                                   enum fib_event_type event_type,
 326                                   struct fib_rule *rule, int family)
 327 {
 328         struct fib_rule_notifier_info info = {
 329                 .info.family = family,
 330                 .rule = rule,
 331         };
 332
 333         return call_fib_notifier(nb, net, event_type, &info.info);
 334 }
 335
 336 static int call_fib_rule_notifiers(struct net *net,
 337                                    enum fib_event_type event_type,
 338                                    struct fib_rule *rule,
 339                                    struct fib_rules_ops *ops,
 340                                    struct netlink_ext_ack *extack)
 341 {
 342         struct fib_rule_notifier_info info = {
 343                 .info.family = ops->family,
 344                 .info.extack = extack,
 345                 .rule = rule,
 346         };
 347
 348         ops->fib_rules_seq++;
 349         return call_fib_notifiers(net, event_type, &info.info);
 350 }
 351
 352 /* Called with rcu_read_lock() */
 353 int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
 354 {
 355         struct fib_rules_ops *ops;
 356         struct fib_rule *rule;
 357
 358         ops = lookup_rules_ops(net, family);
 359         if (!ops)
 360                 return -EAFNOSUPPORT;
 361         list_for_each_entry_rcu(rule, &ops->rules_list, list)
 362                 call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
 363                                        family);
 364         rules_ops_put(ops);
 365
 366         return 0;
 367 }
 368 EXPORT_SYMBOL_GPL(fib_rules_dump);
 369
 370 unsigned int fib_rules_seq_read(struct net *net, int family)
 371 {
 372         unsigned int fib_rules_seq;
 373         struct fib_rules_ops *ops;
 374
 375         ASSERT_RTNL();
 376
 377         ops = lookup_rules_ops(net, family);
 378         if (!ops)
 379                 return 0;
 380         fib_rules_seq = ops->fib_rules_seq;
 381         rules_ops_put(ops);
 382
 383         return fib_rules_seq;
 384 }
 385 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 386
 387 static struct fib_rule *rule_find(struct fib_rules_ops *ops,
 388                                   struct fib_rule_hdr *frh,
 389                                   struct nlattr **tb,
 390                                   struct fib_rule *rule,
 391                                   bool user_priority)
 392 {
 393         struct fib_rule *r;
 394
 395         list_for_each_entry(r, &ops->rules_list, list) {
 396                 if (rule->action && r->action != rule->action)
 397                         continue;
 398
 399                 if (rule->table && r->table != rule->table)
 400                         continue;
 401
 402                 if (user_priority && r->pref != rule->pref)
 403                         continue;
 404
 405                 if (rule->iifname[0] &&
 406                     memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 407                         continue;
 408
 409                 if (rule->oifname[0] &&
 410                     memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 411                         continue;
 412
 413                 if (rule->mark && r->mark != rule->mark)
 414                         continue;
 415
 416                 if (rule->suppress_ifgroup != -1 &&
 417                     r->suppress_ifgroup != rule->suppress_ifgroup)
 418                         continue;
 419
 420                 if (rule->suppress_prefixlen != -1 &&
 421                     r->suppress_prefixlen != rule->suppress_prefixlen)
 422                         continue;
 423
 424                 if (rule->mark_mask && r->mark_mask != rule->mark_mask)
 425                         continue;
 426
 427                 if (rule->tun_id && r->tun_id != rule->tun_id)
 428                         continue;
 429
 430                 if (r->fr_net != rule->fr_net)
 431                         continue;
 432
 433                 if (rule->l3mdev && r->l3mdev != rule->l3mdev)
 434                         continue;
 435
 436                 if (uid_range_set(&rule->uid_range) &&
 437                     (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 438                     !uid_eq(r->uid_range.end, rule->uid_range.end)))
 439                         continue;
 440
 441                 if (rule->ip_proto && r->ip_proto != rule->ip_proto)
 442                         continue;
 443
 444                 if (rule->proto && r->proto != rule->proto)
 445                         continue;
 446
 447                 if (fib_rule_port_range_set(&rule->sport_range) &&
 448                     !fib_rule_port_range_compare(&r->sport_range,
 449                                                  &rule->sport_range))
 450                         continue;
 451
 452                 if (fib_rule_port_range_set(&rule->dport_range) &&
 453                     !fib_rule_port_range_compare(&r->dport_range,
 454                                                  &rule->dport_range))
 455                         continue;
 456
 457                 if (!ops->compare(r, frh, tb))
 458                         continue;
 459                 return r;
 460         }
 461
 462         return NULL;
 463 }
 464
 465 #ifdef CONFIG_NET_L3_MASTER_DEV
 466 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 467                               struct netlink_ext_ack *extack)
 468 {
 469         nlrule->l3mdev = nla_get_u8(nla);
 470         if (nlrule->l3mdev != 1) {
 471                 NL_SET_ERR_MSG(extack, "Invalid l3mdev attribute");
 472                 return -1;
 473         }
 474
 475         return 0;
 476 }
 477 #else
 478 static int fib_nl2rule_l3mdev(struct nlattr *nla, struct fib_rule *nlrule,
 479                               struct netlink_ext_ack *extack)
 480 {
 481         NL_SET_ERR_MSG(extack, "l3mdev support is not enabled in kernel");
 482         return -1;
 483 }
 484 #endif
 485
 486 static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
 487                        struct netlink_ext_ack *extack,
 488                        struct fib_rules_ops *ops,
 489                        struct nlattr *tb[],
 490                        struct fib_rule **rule,
 491                        bool *user_priority)
 492 {
 493         struct net *net = sock_net(skb->sk);
 494         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 495         struct fib_rule *nlrule = NULL;
 496         int err = -EINVAL;
 497
 498         if (frh->src_len)
 499                 if (!tb[FRA_SRC] ||
 500                     frh->src_len > (ops->addr_size * 8) ||
 501                     nla_len(tb[FRA_SRC]) != ops->addr_size) {
 502                         NL_SET_ERR_MSG(extack, "Invalid source address");
 503                         goto errout;
 504         }
 505
 506         if (frh->dst_len)
 507                 if (!tb[FRA_DST] ||
 508                     frh->dst_len > (ops->addr_size * 8) ||
 509                     nla_len(tb[FRA_DST]) != ops->addr_size) {
 510                         NL_SET_ERR_MSG(extack, "Invalid dst address");
 511                         goto errout;
 512         }
 513
 514         nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
 515         if (!nlrule) {
 516                 err = -ENOMEM;
 517                 goto errout;
 518         }
 519         refcount_set(&nlrule->refcnt, 1);
 520         nlrule->fr_net = net;
 521
 522         if (tb[FRA_PRIORITY]) {
 523                 nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
 524                 *user_priority = true;
 525         } else {
 526                 nlrule->pref = fib_default_rule_pref(ops);
 527         }
 528
 529         nlrule->proto = tb[FRA_PROTOCOL] ?
 530                 nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
 531
 532         if (tb[FRA_IIFNAME]) {
 533                 struct net_device *dev;
 534
 535                 nlrule->iifindex = -1;
 536                 nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
 537                 dev = __dev_get_by_name(net, nlrule->iifname);
 538                 if (dev)
 539                         nlrule->iifindex = dev->ifindex;
 540         }
 541
 542         if (tb[FRA_OIFNAME]) {
 543                 struct net_device *dev;
 544
 545                 nlrule->oifindex = -1;
 546                 nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
 547                 dev = __dev_get_by_name(net, nlrule->oifname);
 548                 if (dev)
 549                         nlrule->oifindex = dev->ifindex;
 550         }
 551
 552         if (tb[FRA_FWMARK]) {
 553                 nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
 554                 if (nlrule->mark)
 555                         /* compatibility: if the mark value is non-zero all bits
 556                          * are compared unless a mask is explicitly specified.
 557                          */
 558                         nlrule->mark_mask = 0xFFFFFFFF;
 559         }
 560
 561         if (tb[FRA_FWMASK])
 562                 nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 563
 564         if (tb[FRA_TUN_ID])
 565                 nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 566
 567         err = -EINVAL;
 568         if (tb[FRA_L3MDEV] &&
 569             fib_nl2rule_l3mdev(tb[FRA_L3MDEV], nlrule, extack) < 0)
 570                 goto errout_free;
 571
 572         nlrule->action = frh->action;
 573         nlrule->flags = frh->flags;
 574         nlrule->table = frh_get_table(frh, tb);
 575         if (tb[FRA_SUPPRESS_PREFIXLEN])
 576                 nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 577         else
 578                 nlrule->suppress_prefixlen = -1;
 579
 580         if (tb[FRA_SUPPRESS_IFGROUP])
 581                 nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 582         else
 583                 nlrule->suppress_ifgroup = -1;
 584
 585         if (tb[FRA_GOTO]) {
 586                 if (nlrule->action != FR_ACT_GOTO) {
 587                         NL_SET_ERR_MSG(extack, "Unexpected goto");
 588                         goto errout_free;
 589                 }
 590
 591                 nlrule->target = nla_get_u32(tb[FRA_GOTO]);
 592                 /* Backward jumps are prohibited to avoid endless loops */
 593                 if (nlrule->target <= nlrule->pref) {
 594                         NL_SET_ERR_MSG(extack, "Backward goto not supported");
 595                         goto errout_free;
 596                 }
 597         } else if (nlrule->action == FR_ACT_GOTO) {
 598                 NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
 599                 goto errout_free;
 600         }
 601
 602         if (nlrule->l3mdev && nlrule->table) {
 603                 NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
 604                 goto errout_free;
 605         }
 606
 607         if (tb[FRA_UID_RANGE]) {
 608                 if (current_user_ns() != net->user_ns) {
 609                         err = -EPERM;
 610                         NL_SET_ERR_MSG(extack, "No permission to set uid");
 611                         goto errout_free;
 612                 }
 613
 614                 nlrule->uid_range = nla_get_kuid_range(tb);
 615
 616                 if (!uid_range_set(&nlrule->uid_range) ||
 617                     !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
 618                         NL_SET_ERR_MSG(extack, "Invalid uid range");
 619                         goto errout_free;
 620                 }
 621         } else {
 622                 nlrule->uid_range = fib_kuid_range_unset;
 623         }
 624
 625         if (tb[FRA_IP_PROTO])
 626                 nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
 627
 628         if (tb[FRA_SPORT_RANGE]) {
 629                 err = nla_get_port_range(tb[FRA_SPORT_RANGE],
 630                                          &nlrule->sport_range);
 631                 if (err) {
 632                         NL_SET_ERR_MSG(extack, "Invalid sport range");
 633                         goto errout_free;
 634                 }
 635         }
 636
 637         if (tb[FRA_DPORT_RANGE]) {
 638                 err = nla_get_port_range(tb[FRA_DPORT_RANGE],
 639                                          &nlrule->dport_range);
 640                 if (err) {
 641                         NL_SET_ERR_MSG(extack, "Invalid dport range");
 642                         goto errout_free;
 643                 }
 644         }
 645
 646         *rule = nlrule;
 647
 648         return 0;
 649
 650 errout_free:
 651         kfree(nlrule);
 652 errout:
 653         return err;
 654 }
 655
 656 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
 657                        struct nlattr **tb, struct fib_rule *rule)
 658 {
 659         struct fib_rule *r;
 660
 661         list_for_each_entry(r, &ops->rules_list, list) {
 662                 if (r->action != rule->action)
 663                         continue;
 664
 665                 if (r->table != rule->table)
 666                         continue;
 667
 668                 if (r->pref != rule->pref)
 669                         continue;
 670
 671                 if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 672                         continue;
 673
 674                 if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 675                         continue;
 676
 677                 if (r->mark != rule->mark)
 678                         continue;
 679
 680                 if (r->suppress_ifgroup != rule->suppress_ifgroup)
 681                         continue;
 682
 683                 if (r->suppress_prefixlen != rule->suppress_prefixlen)
 684                         continue;
 685
 686                 if (r->mark_mask != rule->mark_mask)
 687                         continue;
 688
 689                 if (r->tun_id != rule->tun_id)
 690                         continue;
 691
 692                 if (r->fr_net != rule->fr_net)
 693                         continue;
 694
 695                 if (r->l3mdev != rule->l3mdev)
 696                         continue;
 697
 698                 if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
 699                     !uid_eq(r->uid_range.end, rule->uid_range.end))
 700                         continue;
 701
 702                 if (r->ip_proto != rule->ip_proto)
 703                         continue;
 704
 705                 if (r->proto != rule->proto)
 706                         continue;
 707
 708                 if (!fib_rule_port_range_compare(&r->sport_range,
 709                                                  &rule->sport_range))
 710                         continue;
 711
 712                 if (!fib_rule_port_range_compare(&r->dport_range,
 713                                                  &rule->dport_range))
 714                         continue;
 715
 716                 if (!ops->compare(r, frh, tb))
 717                         continue;
 718                 return 1;
 719         }
 720         return 0;
 721 }
 722
 723 int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 724                    struct netlink_ext_ack *extack)
 725 {
 726         struct net *net = sock_net(skb->sk);
 727         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 728         struct fib_rules_ops *ops = NULL;
 729         struct fib_rule *rule = NULL, *r, *last = NULL;
 730         struct nlattr *tb[FRA_MAX + 1];
 731         int err = -EINVAL, unresolved = 0;
 732         bool user_priority = false;
 733
 734         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 735                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 736                 goto errout;
 737         }
 738
 739         ops = lookup_rules_ops(net, frh->family);
 740         if (!ops) {
 741                 err = -EAFNOSUPPORT;
 742                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 743                 goto errout;
 744         }
 745
 746         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
 747                                      ops->policy, extack);
 748         if (err < 0) {
 749                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 750                 goto errout;
 751         }
 752
 753         err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
 754         if (err)
 755                 goto errout;
 756
 757         if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
 758             rule_exists(ops, frh, tb, rule)) {
 759                 err = -EEXIST;
 760                 goto errout_free;
 761         }
 762
 763         err = ops->configure(rule, skb, frh, tb, extack);
 764         if (err < 0)
 765                 goto errout_free;
 766
 767         err = call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule, ops,
 768                                       extack);
 769         if (err < 0)
 770                 goto errout_free;
 771
 772         list_for_each_entry(r, &ops->rules_list, list) {
 773                 if (r->pref == rule->target) {
 774                         RCU_INIT_POINTER(rule->ctarget, r);
 775                         break;
 776                 }
 777         }
 778
 779         if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
 780                 unresolved = 1;
 781
 782         list_for_each_entry(r, &ops->rules_list, list) {
 783                 if (r->pref > rule->pref)
 784                         break;
 785                 last = r;
 786         }
 787
 788         if (last)
 789                 list_add_rcu(&rule->list, &last->list);
 790         else
 791                 list_add_rcu(&rule->list, &ops->rules_list);
 792
 793         if (ops->unresolved_rules) {
 794                 /*
 795                  * There are unresolved goto rules in the list, check if
 796                  * any of them are pointing to this new rule.
 797                  */
 798                 list_for_each_entry(r, &ops->rules_list, list) {
 799                         if (r->action == FR_ACT_GOTO &&
 800                             r->target == rule->pref &&
 801                             rtnl_dereference(r->ctarget) == NULL) {
 802                                 rcu_assign_pointer(r->ctarget, rule);
 803                                 if (--ops->unresolved_rules == 0)
 804                                         break;
 805                         }
 806                 }
 807         }
 808
 809         if (rule->action == FR_ACT_GOTO)
 810                 ops->nr_goto_rules++;
 811
 812         if (unresolved)
 813                 ops->unresolved_rules++;
 814
 815         if (rule->tun_id)
 816                 ip_tunnel_need_metadata();
 817
 818         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
 819         flush_route_cache(ops);
 820         rules_ops_put(ops);
 821         return 0;
 822
 823 errout_free:
 824         kfree(rule);
 825 errout:
 826         rules_ops_put(ops);
 827         return err;
 828 }
 829 EXPORT_SYMBOL_GPL(fib_nl_newrule);
 830
 831 int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 832                    struct netlink_ext_ack *extack)
 833 {
 834         struct net *net = sock_net(skb->sk);
 835         struct fib_rule_hdr *frh = nlmsg_data(nlh);
 836         struct fib_rules_ops *ops = NULL;
 837         struct fib_rule *rule = NULL, *r, *nlrule = NULL;
 838         struct nlattr *tb[FRA_MAX+1];
 839         int err = -EINVAL;
 840         bool user_priority = false;
 841
 842         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
 843                 NL_SET_ERR_MSG(extack, "Invalid msg length");
 844                 goto errout;
 845         }
 846
 847         ops = lookup_rules_ops(net, frh->family);
 848         if (ops == NULL) {
 849                 err = -EAFNOSUPPORT;
 850                 NL_SET_ERR_MSG(extack, "Rule family not supported");
 851                 goto errout;
 852         }
 853
 854         err = nlmsg_parse_deprecated(nlh, sizeof(*frh), tb, FRA_MAX,
 855                                      ops->policy, extack);
 856         if (err < 0) {
 857                 NL_SET_ERR_MSG(extack, "Error parsing msg");
 858                 goto errout;
 859         }
 860
 861         err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
 862         if (err)
 863                 goto errout;
 864
 865         rule = rule_find(ops, frh, tb, nlrule, user_priority);
 866         if (!rule) {
 867                 err = -ENOENT;
 868                 goto errout;
 869         }
 870
 871         if (rule->flags & FIB_RULE_PERMANENT) {
 872                 err = -EPERM;
 873                 goto errout;
 874         }
 875
 876         if (ops->delete) {
 877                 err = ops->delete(rule);
 878                 if (err)
 879                         goto errout;
 880         }
 881
 882         if (rule->tun_id)
 883                 ip_tunnel_unneed_metadata();
 884
 885         list_del_rcu(&rule->list);
 886
 887         if (rule->action == FR_ACT_GOTO) {
 888                 ops->nr_goto_rules--;
 889                 if (rtnl_dereference(rule->ctarget) == NULL)
 890                         ops->unresolved_rules--;
 891         }
 892
 893         /*
 894          * Check if this rule is a target to any of them. If so,
 895          * adjust to the next one with the same preference or
 896          * disable them. As this operation is eventually very
 897          * expensive, it is only performed if goto rules, except
 898          * current if it is goto rule, have actually been added.
 899          */
 900         if (ops->nr_goto_rules > 0) {
 901                 struct fib_rule *n;
 902
 903                 n = list_next_entry(rule, list);
 904                 if (&n->list == &ops->rules_list || n->pref != rule->pref)
 905                         n = NULL;
 906                 list_for_each_entry(r, &ops->rules_list, list) {
 907                         if (rtnl_dereference(r->ctarget) != rule)
 908                                 continue;
 909                         rcu_assign_pointer(r->ctarget, n);
 910                         if (!n)
 911                                 ops->unresolved_rules++;
 912                 }
 913         }
 914
 915         call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
 916                                 NULL);
 917         notify_rule_change(RTM_DELRULE, rule, ops, nlh,
 918                            NETLINK_CB(skb).portid);
 919         fib_rule_put(rule);
 920         flush_route_cache(ops);
 921         rules_ops_put(ops);
 922         kfree(nlrule);
 923         return 0;
 924
 925 errout:
 926         kfree(nlrule);
 927         rules_ops_put(ops);
 928         return err;
 929 }
 930 EXPORT_SYMBOL_GPL(fib_nl_delrule);
 931
 932 static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 933                                          struct fib_rule *rule)
 934 {
 935         size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
 936                          + nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
 937                          + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
 938                          + nla_total_size(4) /* FRA_PRIORITY */
 939                          + nla_total_size(4) /* FRA_TABLE */
 940                          + nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
 941                          + nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
 942                          + nla_total_size(4) /* FRA_FWMARK */
 943                          + nla_total_size(4) /* FRA_FWMASK */
 944                          + nla_total_size_64bit(8) /* FRA_TUN_ID */
 945                          + nla_total_size(sizeof(struct fib_kuid_range))
 946                          + nla_total_size(1) /* FRA_PROTOCOL */
 947                          + nla_total_size(1) /* FRA_IP_PROTO */
 948                          + nla_total_size(sizeof(struct fib_rule_port_range)) /* FRA_SPORT_RANGE */
 949                          + nla_total_size(sizeof(struct fib_rule_port_range)); /* FRA_DPORT_RANGE */
 950
 951         if (ops->nlmsg_payload)
 952                 payload += ops->nlmsg_payload(rule);
 953
 954         return payload;
 955 }
 956
 957 static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 958                             u32 pid, u32 seq, int type, int flags,
 959                             struct fib_rules_ops *ops)
 960 {
 961         struct nlmsghdr *nlh;
 962         struct fib_rule_hdr *frh;
 963
 964         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 965         if (nlh == NULL)
 966                 return -EMSGSIZE;
 967
 968         frh = nlmsg_data(nlh);
 969         frh->family = ops->family;
 970         frh->table = rule->table < 256 ? rule->table : RT_TABLE_COMPAT;
 971         if (nla_put_u32(skb, FRA_TABLE, rule->table))
 972                 goto nla_put_failure;
 973         if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 974                 goto nla_put_failure;
 975         frh->res1 = 0;
 976         frh->res2 = 0;
 977         frh->action = rule->action;
 978         frh->flags = rule->flags;
 979
 980         if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
 981                 goto nla_put_failure;
 982
 983         if (rule->action == FR_ACT_GOTO &&
 984             rcu_access_pointer(rule->ctarget) == NULL)
 985                 frh->flags |= FIB_RULE_UNRESOLVED;
 986
 987         if (rule->iifname[0]) {
 988                 if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
 989                         goto nla_put_failure;
 990                 if (rule->iifindex == -1)
 991                         frh->flags |= FIB_RULE_IIF_DETACHED;
 992         }
 993
 994         if (rule->oifname[0]) {
 995                 if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
 996                         goto nla_put_failure;
 997                 if (rule->oifindex == -1)
 998                         frh->flags |= FIB_RULE_OIF_DETACHED;
 999         }
1000
1001         if ((rule->pref &&
1002              nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
1003             (rule->mark &&
1004              nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
1005             ((rule->mark_mask || rule->mark) &&
1006              nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
1007             (rule->target &&
1008              nla_put_u32(skb, FRA_GOTO, rule->target)) ||
1009             (rule->tun_id &&
1010              nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
1011             (rule->l3mdev &&
1012              nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
1013             (uid_range_set(&rule->uid_range) &&
1014              nla_put_uid_range(skb, &rule->uid_range)) ||
1015             (fib_rule_port_range_set(&rule->sport_range) &&
1016              nla_put_port_range(skb, FRA_SPORT_RANGE, &rule->sport_range)) ||
1017             (fib_rule_port_range_set(&rule->dport_range) &&
1018              nla_put_port_range(skb, FRA_DPORT_RANGE, &rule->dport_range)) ||
1019             (rule->ip_proto && nla_put_u8(skb, FRA_IP_PROTO, rule->ip_proto)))
1020                 goto nla_put_failure;
1021
1022         if (rule->suppress_ifgroup != -1) {
1023                 if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
1024                         goto nla_put_failure;
1025         }
1026
1027         if (ops->fill(rule, skb, frh) < 0)
1028                 goto nla_put_failure;
1029
1030         nlmsg_end(skb, nlh);
1031         return 0;
1032
1033 nla_put_failure:
1034         nlmsg_cancel(skb, nlh);
1035         return -EMSGSIZE;
1036 }
1037
1038 static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
1039                       struct fib_rules_ops *ops)
1040 {
1041         int idx = 0;
1042         struct fib_rule *rule;
1043         int err = 0;
1044
1045         rcu_read_lock();
1046         list_for_each_entry_rcu(rule, &ops->rules_list, list) {
1047                 if (idx < cb->args[1])
1048                         goto skip;
1049
1050                 err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
1051                                        cb->nlh->nlmsg_seq, RTM_NEWRULE,
1052                                        NLM_F_MULTI, ops);
1053                 if (err)
1054                         break;
1055 skip:
1056                 idx++;
1057         }
1058         rcu_read_unlock();
1059         cb->args[1] = idx;
1060         rules_ops_put(ops);
1061
1062         return err;
1063 }
1064
1065 static int fib_valid_dumprule_req(const struct nlmsghdr *nlh,
1066                                    struct netlink_ext_ack *extack)
1067 {
1068         struct fib_rule_hdr *frh;
1069
1070         if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
1071                 NL_SET_ERR_MSG(extack, "Invalid header for fib rule dump request");
1072                 return -EINVAL;
1073         }
1074
1075         frh = nlmsg_data(nlh);
1076         if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
1077             frh->res1 || frh->res2 || frh->action || frh->flags) {
1078                 NL_SET_ERR_MSG(extack,
1079                                "Invalid values in header for fib rule dump request");
1080                 return -EINVAL;
1081         }
1082
1083         if (nlmsg_attrlen(nlh, sizeof(*frh))) {
1084                 NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
1085                 return -EINVAL;
1086         }
1087
1088         return 0;
1089 }
1090
1091 static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
1092 {
1093         const struct nlmsghdr *nlh = cb->nlh;
1094         struct net *net = sock_net(skb->sk);
1095         struct fib_rules_ops *ops;
1096         int idx = 0, family;
1097
1098         if (cb->strict_check) {
1099                 int err = fib_valid_dumprule_req(nlh, cb->extack);
1100
1101                 if (err < 0)
1102                         return err;
1103         }
1104
1105         family = rtnl_msg_family(nlh);
1106         if (family != AF_UNSPEC) {
1107                 /* Protocol specific dump request */
1108                 ops = lookup_rules_ops(net, family);
1109                 if (ops == NULL)
1110                         return -EAFNOSUPPORT;
1111
1112                 dump_rules(skb, cb, ops);
1113
1114                 return skb->len;
1115         }
1116
1117         rcu_read_lock();
1118         list_for_each_entry_rcu(ops, &net->rules_ops, list) {
1119                 if (idx < cb->args[0] || !try_module_get(ops->owner))
1120                         goto skip;
1121
1122                 if (dump_rules(skb, cb, ops) < 0)
1123                         break;
1124
1125                 cb->args[1] = 0;
1126 skip:
1127                 idx++;
1128         }
1129         rcu_read_unlock();
1130         cb->args[0] = idx;
1131
1132         return skb->len;
1133 }
1134
1135 static void notify_rule_change(int event, struct fib_rule *rule,
1136                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
1137                                u32 pid)
1138 {
1139         struct net *net;
1140         struct sk_buff *skb;
1141         int err = -ENOMEM;
1142
1143         net = ops->fro_net;
1144         skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
1145         if (skb == NULL)
1146                 goto errout;
1147
1148         err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
1149         if (err < 0) {
1150                 /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
1151                 WARN_ON(err == -EMSGSIZE);
1152                 kfree_skb(skb);
1153                 goto errout;
1154         }
1155
1156         rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
1157         return;
1158 errout:
1159         if (err < 0)
1160                 rtnl_set_sk_err(net, ops->nlgroup, err);
1161 }
1162
1163 static void attach_rules(struct list_head *rules, struct net_device *dev)
1164 {
1165         struct fib_rule *rule;
1166
1167         list_for_each_entry(rule, rules, list) {
1168                 if (rule->iifindex == -1 &&
1169                     strcmp(dev->name, rule->iifname) == 0)
1170                         rule->iifindex = dev->ifindex;
1171                 if (rule->oifindex == -1 &&
1172                     strcmp(dev->name, rule->oifname) == 0)
1173                         rule->oifindex = dev->ifindex;
1174         }
1175 }
1176
1177 static void detach_rules(struct list_head *rules, struct net_device *dev)
1178 {
1179         struct fib_rule *rule;
1180
1181         list_for_each_entry(rule, rules, list) {
1182                 if (rule->iifindex == dev->ifindex)
1183                         rule->iifindex = -1;
1184                 if (rule->oifindex == dev->ifindex)
1185                         rule->oifindex = -1;
1186         }
1187 }
1188
1189
1190 static int fib_rules_event(struct notifier_block *this, unsigned long event,
1191                            void *ptr)
1192 {
1193         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1194         struct net *net = dev_net(dev);
1195         struct fib_rules_ops *ops;
1196
1197         ASSERT_RTNL();
1198
1199         switch (event) {
1200         case NETDEV_REGISTER:
1201                 list_for_each_entry(ops, &net->rules_ops, list)
1202                         attach_rules(&ops->rules_list, dev);
1203                 break;
1204
1205         case NETDEV_CHANGENAME:
1206                 list_for_each_entry(ops, &net->rules_ops, list) {
1207                         detach_rules(&ops->rules_list, dev);
1208                         attach_rules(&ops->rules_list, dev);
1209                 }
1210                 break;
1211
1212         case NETDEV_UNREGISTER:
1213                 list_for_each_entry(ops, &net->rules_ops, list)
1214                         detach_rules(&ops->rules_list, dev);
1215                 break;
1216         }
1217
1218         return NOTIFY_DONE;
1219 }
1220
1221 static struct notifier_block fib_rules_notifier = {
1222         .notifier_call = fib_rules_event,
1223 };
1224
1225 static int __net_init fib_rules_net_init(struct net *net)
1226 {
1227         INIT_LIST_HEAD(&net->rules_ops);
1228         spin_lock_init(&net->rules_mod_lock);
1229         return 0;
1230 }
1231
1232 static void __net_exit fib_rules_net_exit(struct net *net)
1233 {
1234         WARN_ON_ONCE(!list_empty(&net->rules_ops));
1235 }
1236
1237 static struct pernet_operations fib_rules_net_ops = {
1238         .init = fib_rules_net_init,
1239         .exit = fib_rules_net_exit,
1240 };
1241
1242 static int __init fib_rules_init(void)
1243 {
1244         int err;
1245         rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, 0);
1246         rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, 0);
1247         rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, 0);
1248
1249         err = register_pernet_subsys(&fib_rules_net_ops);
1250         if (err < 0)
1251                 goto fail;
1252
1253         err = register_netdevice_notifier(&fib_rules_notifier);
1254         if (err < 0)
1255                 goto fail_unregister;
1256
1257         return 0;
1258
1259 fail_unregister:
1260         unregister_pernet_subsys(&fib_rules_net_ops);
1261 fail:
1262         rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
1263         rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
1264         rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
1265         return err;
1266 }
1267
1268 subsys_initcall(fib_rules_init);