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