net/sctp/bind_addr.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* SCTP kernel implementation
   3  * (C) Copyright IBM Corp. 2001, 2003
   4  * Copyright (c) Cisco 1999,2000
   5  * Copyright (c) Motorola 1999,2000,2001
   6  * Copyright (c) La Monte H.P. Yarroll 2001
   7  *
   8  * This file is part of the SCTP kernel implementation.
   9  *
  10  * A collection class to handle the storage of transport addresses.
  11  *
  12  * Please send any bug reports or fixes you make to the
  13  * email address(es):
  14  *    lksctp developers <linux-sctp@vger.kernel.org>
  15  *
  16  * Written or modified by:
  17  *    La Monte H.P. Yarroll <piggy@acm.org>
  18  *    Karl Knutson          <karl@athena.chicago.il.us>
  19  *    Jon Grimm             <jgrimm@us.ibm.com>
  20  *    Daisy Chang           <daisyc@us.ibm.com>
  21  */
  22
  23 #include <linux/types.h>
  24 #include <linux/slab.h>
  25 #include <linux/in.h>
  26 #include <net/sock.h>
  27 #include <net/ipv6.h>
  28 #include <net/if_inet6.h>
  29 #include <net/sctp/sctp.h>
  30 #include <net/sctp/sm.h>
  31
  32 /* Forward declarations for internal helpers. */
  33 static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
  34                               union sctp_addr *addr, enum sctp_scope scope,
  35                               gfp_t gfp, int flags);
  36 static void sctp_bind_addr_clean(struct sctp_bind_addr *);
  37
  38 /* First Level Abstractions. */
  39
  40 /* Copy 'src' to 'dest' taking 'scope' into account.  Omit addresses
  41  * in 'src' which have a broader scope than 'scope'.
  42  */
  43 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
  44                         const struct sctp_bind_addr *src,
  45                         enum sctp_scope scope, gfp_t gfp,
  46                         int flags)
  47 {
  48         struct sctp_sockaddr_entry *addr;
  49         int error = 0;
  50
  51         /* All addresses share the same port.  */
  52         dest->port = src->port;
  53
  54         /* Extract the addresses which are relevant for this scope.  */
  55         list_for_each_entry(addr, &src->address_list, list) {
  56                 error = sctp_copy_one_addr(net, dest, &addr->a, scope,
  57                                            gfp, flags);
  58                 if (error < 0)
  59                         goto out;
  60         }
  61
  62         /* If there are no addresses matching the scope and
  63          * this is global scope, try to get a link scope address, with
  64          * the assumption that we must be sitting behind a NAT.
  65          */
  66         if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {
  67                 list_for_each_entry(addr, &src->address_list, list) {
  68                         error = sctp_copy_one_addr(net, dest, &addr->a,
  69                                                    SCTP_SCOPE_LINK, gfp,
  70                                                    flags);
  71                         if (error < 0)
  72                                 goto out;
  73                 }
  74         }
  75
  76         /* If somehow no addresses were found that can be used with this
  77          * scope, it's an error.
  78          */
  79         if (list_empty(&dest->address_list))
  80                 error = -ENETUNREACH;
  81
  82 out:
  83         if (error)
  84                 sctp_bind_addr_clean(dest);
  85
  86         return error;
  87 }
  88
  89 /* Exactly duplicate the address lists.  This is necessary when doing
  90  * peer-offs and accepts.  We don't want to put all the current system
  91  * addresses into the endpoint.  That's useless.  But we do want duplicat
  92  * the list of bound addresses that the older endpoint used.
  93  */
  94 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
  95                         const struct sctp_bind_addr *src,
  96                         gfp_t gfp)
  97 {
  98         struct sctp_sockaddr_entry *addr;
  99         int error = 0;
 100
 101         /* All addresses share the same port.  */
 102         dest->port = src->port;
 103
 104         list_for_each_entry(addr, &src->address_list, list) {
 105                 error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
 106                                            1, gfp);
 107                 if (error < 0)
 108                         break;
 109         }
 110
 111         return error;
 112 }
 113
 114 /* Initialize the SCTP_bind_addr structure for either an endpoint or
 115  * an association.
 116  */
 117 void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
 118 {
 119         INIT_LIST_HEAD(&bp->address_list);
 120         bp->port = port;
 121 }
 122
 123 /* Dispose of the address list. */
 124 static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
 125 {
 126         struct sctp_sockaddr_entry *addr, *temp;
 127
 128         /* Empty the bind address list. */
 129         list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
 130                 list_del_rcu(&addr->list);
 131                 kfree_rcu(addr, rcu);
 132                 SCTP_DBG_OBJCNT_DEC(addr);
 133         }
 134 }
 135
 136 /* Dispose of an SCTP_bind_addr structure  */
 137 void sctp_bind_addr_free(struct sctp_bind_addr *bp)
 138 {
 139         /* Empty the bind address list. */
 140         sctp_bind_addr_clean(bp);
 141 }
 142
 143 /* Add an address to the bind address list in the SCTP_bind_addr structure. */
 144 int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
 145                        int new_size, __u8 addr_state, gfp_t gfp)
 146 {
 147         struct sctp_sockaddr_entry *addr;
 148
 149         /* Add the address to the bind address list.  */
 150         addr = kzalloc(sizeof(*addr), gfp);
 151         if (!addr)
 152                 return -ENOMEM;
 153
 154         memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));
 155
 156         /* Fix up the port if it has not yet been set.
 157          * Both v4 and v6 have the port at the same offset.
 158          */
 159         if (!addr->a.v4.sin_port)
 160                 addr->a.v4.sin_port = htons(bp->port);
 161
 162         addr->state = addr_state;
 163         addr->valid = 1;
 164
 165         INIT_LIST_HEAD(&addr->list);
 166
 167         /* We always hold a socket lock when calling this function,
 168          * and that acts as a writer synchronizing lock.
 169          */
 170         list_add_tail_rcu(&addr->list, &bp->address_list);
 171         SCTP_DBG_OBJCNT_INC(addr);
 172
 173         return 0;
 174 }
 175
 176 /* Delete an address from the bind address list in the SCTP_bind_addr
 177  * structure.
 178  */
 179 int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
 180 {
 181         struct sctp_sockaddr_entry *addr, *temp;
 182         int found = 0;
 183
 184         /* We hold the socket lock when calling this function,
 185          * and that acts as a writer synchronizing lock.
 186          */
 187         list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
 188                 if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
 189                         /* Found the exact match. */
 190                         found = 1;
 191                         addr->valid = 0;
 192                         list_del_rcu(&addr->list);
 193                         break;
 194                 }
 195         }
 196
 197         if (found) {
 198                 kfree_rcu(addr, rcu);
 199                 SCTP_DBG_OBJCNT_DEC(addr);
 200                 return 0;
 201         }
 202
 203         return -EINVAL;
 204 }
 205
 206 /* Create a network byte-order representation of all the addresses
 207  * formated as SCTP parameters.
 208  *
 209  * The second argument is the return value for the length.
 210  */
 211 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
 212                                          int *addrs_len,
 213                                          gfp_t gfp)
 214 {
 215         union sctp_params addrparms;
 216         union sctp_params retval;
 217         int addrparms_len;
 218         union sctp_addr_param rawaddr;
 219         int len;
 220         struct sctp_sockaddr_entry *addr;
 221         struct list_head *pos;
 222         struct sctp_af *af;
 223
 224         addrparms_len = 0;
 225         len = 0;
 226
 227         /* Allocate enough memory at once. */
 228         list_for_each(pos, &bp->address_list) {
 229                 len += sizeof(union sctp_addr_param);
 230         }
 231
 232         /* Don't even bother embedding an address if there
 233          * is only one.
 234          */
 235         if (len == sizeof(union sctp_addr_param)) {
 236                 retval.v = NULL;
 237                 goto end_raw;
 238         }
 239
 240         retval.v = kmalloc(len, gfp);
 241         if (!retval.v)
 242                 goto end_raw;
 243
 244         addrparms = retval;
 245
 246         list_for_each_entry(addr, &bp->address_list, list) {
 247                 af = sctp_get_af_specific(addr->a.v4.sin_family);
 248                 len = af->to_addr_param(&addr->a, &rawaddr);
 249                 memcpy(addrparms.v, &rawaddr, len);
 250                 addrparms.v += len;
 251                 addrparms_len += len;
 252         }
 253
 254 end_raw:
 255         *addrs_len = addrparms_len;
 256         return retval;
 257 }
 258
 259 /*
 260  * Create an address list out of the raw address list format (IPv4 and IPv6
 261  * address parameters).
 262  */
 263 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
 264                            int addrs_len, __u16 port, gfp_t gfp)
 265 {
 266         union sctp_addr_param *rawaddr;
 267         struct sctp_paramhdr *param;
 268         union sctp_addr addr;
 269         int retval = 0;
 270         int len;
 271         struct sctp_af *af;
 272
 273         /* Convert the raw address to standard address format */
 274         while (addrs_len) {
 275                 param = (struct sctp_paramhdr *)raw_addr_list;
 276                 rawaddr = (union sctp_addr_param *)raw_addr_list;
 277
 278                 af = sctp_get_af_specific(param_type2af(param->type));
 279                 if (unlikely(!af) ||
 280                     !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
 281                         retval = -EINVAL;
 282                         goto out_err;
 283                 }
 284
 285                 if (sctp_bind_addr_state(bp, &addr) != -1)
 286                         goto next;
 287                 retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
 288                                             SCTP_ADDR_SRC, gfp);
 289                 if (retval)
 290                         /* Can't finish building the list, clean up. */
 291                         goto out_err;
 292
 293 next:
 294                 len = ntohs(param->length);
 295                 addrs_len -= len;
 296                 raw_addr_list += len;
 297         }
 298
 299         return retval;
 300
 301 out_err:
 302         if (retval)
 303                 sctp_bind_addr_clean(bp);
 304
 305         return retval;
 306 }
 307
 308 /********************************************************************
 309  * 2nd Level Abstractions
 310  ********************************************************************/
 311
 312 /* Does this contain a specified address?  Allow wildcarding. */
 313 int sctp_bind_addr_match(struct sctp_bind_addr *bp,
 314                          const union sctp_addr *addr,
 315                          struct sctp_sock *opt)
 316 {
 317         struct sctp_sockaddr_entry *laddr;
 318         int match = 0;
 319
 320         rcu_read_lock();
 321         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 322                 if (!laddr->valid)
 323                         continue;
 324                 if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
 325                         match = 1;
 326                         break;
 327                 }
 328         }
 329         rcu_read_unlock();
 330
 331         return match;
 332 }
 333
 334 int sctp_bind_addrs_check(struct sctp_sock *sp,
 335                           struct sctp_sock *sp2, int cnt2)
 336 {
 337         struct sctp_bind_addr *bp2 = &sp2->ep->base.bind_addr;
 338         struct sctp_bind_addr *bp = &sp->ep->base.bind_addr;
 339         struct sctp_sockaddr_entry *laddr, *laddr2;
 340         bool exist = false;
 341         int cnt = 0;
 342
 343         rcu_read_lock();
 344         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 345                 list_for_each_entry_rcu(laddr2, &bp2->address_list, list) {
 346                         if (sp->pf->af->cmp_addr(&laddr->a, &laddr2->a) &&
 347                             laddr->valid && laddr2->valid) {
 348                                 exist = true;
 349                                 goto next;
 350                         }
 351                 }
 352                 cnt = 0;
 353                 break;
 354 next:
 355                 cnt++;
 356         }
 357         rcu_read_unlock();
 358
 359         return (cnt == cnt2) ? 0 : (exist ? -EEXIST : 1);
 360 }
 361
 362 /* Does the address 'addr' conflict with any addresses in
 363  * the bp.
 364  */
 365 int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
 366                             const union sctp_addr *addr,
 367                             struct sctp_sock *bp_sp,
 368                             struct sctp_sock *addr_sp)
 369 {
 370         struct sctp_sockaddr_entry *laddr;
 371         int conflict = 0;
 372         struct sctp_sock *sp;
 373
 374         /* Pick the IPv6 socket as the basis of comparison
 375          * since it's usually a superset of the IPv4.
 376          * If there is no IPv6 socket, then default to bind_addr.
 377          */
 378         if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
 379                 sp = bp_sp;
 380         else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
 381                 sp = addr_sp;
 382         else
 383                 sp = bp_sp;
 384
 385         rcu_read_lock();
 386         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 387                 if (!laddr->valid)
 388                         continue;
 389
 390                 conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
 391                 if (conflict)
 392                         break;
 393         }
 394         rcu_read_unlock();
 395
 396         return conflict;
 397 }
 398
 399 /* Get the state of the entry in the bind_addr_list */
 400 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
 401                          const union sctp_addr *addr)
 402 {
 403         struct sctp_sockaddr_entry *laddr;
 404         struct sctp_af *af;
 405
 406         af = sctp_get_af_specific(addr->sa.sa_family);
 407         if (unlikely(!af))
 408                 return -1;
 409
 410         list_for_each_entry_rcu(laddr, &bp->address_list, list) {
 411                 if (!laddr->valid)
 412                         continue;
 413                 if (af->cmp_addr(&laddr->a, addr))
 414                         return laddr->state;
 415         }
 416
 417         return -1;
 418 }
 419
 420 /* Find the first address in the bind address list that is not present in
 421  * the addrs packed array.
 422  */
 423 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr   *bp,
 424                                         const union sctp_addr   *addrs,
 425                                         int                     addrcnt,
 426                                         struct sctp_sock        *opt)
 427 {
 428         struct sctp_sockaddr_entry      *laddr;
 429         union sctp_addr                 *addr;
 430         void                            *addr_buf;
 431         struct sctp_af                  *af;
 432         int                             i;
 433
 434         /* This is only called sctp_send_asconf_del_ip() and we hold
 435          * the socket lock in that code patch, so that address list
 436          * can't change.
 437          */
 438         list_for_each_entry(laddr, &bp->address_list, list) {
 439                 addr_buf = (union sctp_addr *)addrs;
 440                 for (i = 0; i < addrcnt; i++) {
 441                         addr = addr_buf;
 442                         af = sctp_get_af_specific(addr->v4.sin_family);
 443                         if (!af)
 444                                 break;
 445
 446                         if (opt->pf->cmp_addr(&laddr->a, addr, opt))
 447                                 break;
 448
 449                         addr_buf += af->sockaddr_len;
 450                 }
 451                 if (i == addrcnt)
 452                         return &laddr->a;
 453         }
 454
 455         return NULL;
 456 }
 457
 458 /* Copy out addresses from the global local address list. */
 459 static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
 460                               union sctp_addr *addr, enum sctp_scope scope,
 461                               gfp_t gfp, int flags)
 462 {
 463         int error = 0;
 464
 465         if (sctp_is_any(NULL, addr)) {
 466                 error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);
 467         } else if (sctp_in_scope(net, addr, scope)) {
 468                 /* Now that the address is in scope, check to see if
 469                  * the address type is supported by local sock as
 470                  * well as the remote peer.
 471                  */
 472                 if ((((AF_INET == addr->sa.sa_family) &&
 473                       (flags & SCTP_ADDR4_ALLOWED) &&
 474                       (flags & SCTP_ADDR4_PEERSUPP))) ||
 475                     (((AF_INET6 == addr->sa.sa_family) &&
 476                       (flags & SCTP_ADDR6_ALLOWED) &&
 477                       (flags & SCTP_ADDR6_PEERSUPP))))
 478                         error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
 479                                                    SCTP_ADDR_SRC, gfp);
 480         }
 481
 482         return error;
 483 }
 484
 485 /* Is this a wildcard address?  */
 486 int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
 487 {
 488         unsigned short fam = 0;
 489         struct sctp_af *af;
 490
 491         /* Try to get the right address family */
 492         if (addr->sa.sa_family != AF_UNSPEC)
 493                 fam = addr->sa.sa_family;
 494         else if (sk)
 495                 fam = sk->sk_family;
 496
 497         af = sctp_get_af_specific(fam);
 498         if (!af)
 499                 return 0;
 500
 501         return af->is_any(addr);
 502 }
 503
 504 /* Is 'addr' valid for 'scope'?  */
 505 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
 506                   enum sctp_scope scope)
 507 {
 508         enum sctp_scope addr_scope = sctp_scope(addr);
 509
 510         /* The unusable SCTP addresses will not be considered with
 511          * any defined scopes.
 512          */
 513         if (SCTP_SCOPE_UNUSABLE == addr_scope)
 514                 return 0;
 515         /*
 516          * For INIT and INIT-ACK address list, let L be the level of
 517          * requested destination address, sender and receiver
 518          * SHOULD include all of its addresses with level greater
 519          * than or equal to L.
 520          *
 521          * Address scoping can be selectively controlled via sysctl
 522          * option
 523          */
 524         switch (net->sctp.scope_policy) {
 525         case SCTP_SCOPE_POLICY_DISABLE:
 526                 return 1;
 527         case SCTP_SCOPE_POLICY_ENABLE:
 528                 if (addr_scope <= scope)
 529                         return 1;
 530                 break;
 531         case SCTP_SCOPE_POLICY_PRIVATE:
 532                 if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
 533                         return 1;
 534                 break;
 535         case SCTP_SCOPE_POLICY_LINK:
 536                 if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
 537                         return 1;
 538                 break;
 539         default:
 540                 break;
 541         }
 542
 543         return 0;
 544 }
 545
 546 int sctp_is_ep_boundall(struct sock *sk)
 547 {
 548         struct sctp_bind_addr *bp;
 549         struct sctp_sockaddr_entry *addr;
 550
 551         bp = &sctp_sk(sk)->ep->base.bind_addr;
 552         if (sctp_list_single_entry(&bp->address_list)) {
 553                 addr = list_entry(bp->address_list.next,
 554                                   struct sctp_sockaddr_entry, list);
 555                 if (sctp_is_any(sk, &addr->a))
 556                         return 1;
 557         }
 558         return 0;
 559 }
 560
 561 /********************************************************************
 562  * 3rd Level Abstractions
 563  ********************************************************************/
 564
 565 /* What is the scope of 'addr'?  */
 566 enum sctp_scope sctp_scope(const union sctp_addr *addr)
 567 {
 568         struct sctp_af *af;
 569
 570         af = sctp_get_af_specific(addr->sa.sa_family);
 571         if (!af)
 572                 return SCTP_SCOPE_UNUSABLE;
 573
 574         return af->scope((union sctp_addr *)addr);
 575 }