net/sctp/endpointola.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* SCTP kernel implementation
   3  * Copyright (c) 1999-2000 Cisco, Inc.
   4  * Copyright (c) 1999-2001 Motorola, Inc.
   5  * Copyright (c) 2001-2002 International Business Machines, Corp.
   6  * Copyright (c) 2001 Intel Corp.
   7  * Copyright (c) 2001 Nokia, Inc.
   8  * Copyright (c) 2001 La Monte H.P. Yarroll
   9  *
  10  * This file is part of the SCTP kernel implementation
  11  *
  12  * This abstraction represents an SCTP endpoint.
  13  *
  14  * Please send any bug reports or fixes you make to the
  15  * email address(es):
  16  *    lksctp developers <linux-sctp@vger.kernel.org>
  17  *
  18  * Written or modified by:
  19  *    La Monte H.P. Yarroll <piggy@acm.org>
  20  *    Karl Knutson <karl@athena.chicago.il.us>
  21  *    Jon Grimm <jgrimm@austin.ibm.com>
  22  *    Daisy Chang <daisyc@us.ibm.com>
  23  *    Dajiang Zhang <dajiang.zhang@nokia.com>
  24  */
  25
  26 #include <linux/types.h>
  27 #include <linux/slab.h>
  28 #include <linux/in.h>
  29 #include <linux/random.h>       /* get_random_bytes() */
  30 #include <net/sock.h>
  31 #include <net/ipv6.h>
  32 #include <net/sctp/sctp.h>
  33 #include <net/sctp/sm.h>
  34
  35 /* Forward declarations for internal helpers. */
  36 static void sctp_endpoint_bh_rcv(struct work_struct *work);
  37
  38 /*
  39  * Initialize the base fields of the endpoint structure.
  40  */
  41 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
  42                                                 struct sock *sk,
  43                                                 gfp_t gfp)
  44 {
  45         struct net *net = sock_net(sk);
  46         struct sctp_hmac_algo_param *auth_hmacs = NULL;
  47         struct sctp_chunks_param *auth_chunks = NULL;
  48         struct sctp_shared_key *null_key;
  49         int err;
  50
  51         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  52         if (!ep->digest)
  53                 return NULL;
  54
  55         ep->auth_enable = net->sctp.auth_enable;
  56         if (ep->auth_enable) {
  57                 /* Allocate space for HMACS and CHUNKS authentication
  58                  * variables.  There are arrays that we encode directly
  59                  * into parameters to make the rest of the operations easier.
  60                  */
  61                 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
  62                                                  SCTP_AUTH_NUM_HMACS), gfp);
  63                 if (!auth_hmacs)
  64                         goto nomem;
  65
  66                 auth_chunks = kzalloc(sizeof(*auth_chunks) +
  67                                       SCTP_NUM_CHUNK_TYPES, gfp);
  68                 if (!auth_chunks)
  69                         goto nomem;
  70
  71                 /* Initialize the HMACS parameter.
  72                  * SCTP-AUTH: Section 3.3
  73                  *    Every endpoint supporting SCTP chunk authentication MUST
  74                  *    support the HMAC based on the SHA-1 algorithm.
  75                  */
  76                 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
  77                 auth_hmacs->param_hdr.length =
  78                                         htons(sizeof(struct sctp_paramhdr) + 2);
  79                 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
  80
  81                 /* Initialize the CHUNKS parameter */
  82                 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
  83                 auth_chunks->param_hdr.length =
  84                                         htons(sizeof(struct sctp_paramhdr));
  85
  86                 /* If the Add-IP functionality is enabled, we must
  87                  * authenticate, ASCONF and ASCONF-ACK chunks
  88                  */
  89                 if (net->sctp.addip_enable) {
  90                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
  91                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
  92                         auth_chunks->param_hdr.length =
  93                                         htons(sizeof(struct sctp_paramhdr) + 2);
  94                 }
  95
  96                 /* Allocate and initialize transorms arrays for supported
  97                  * HMACs.
  98                  */
  99                 err = sctp_auth_init_hmacs(ep, gfp);
 100                 if (err)
 101                         goto nomem;
 102         }
 103
 104         /* Initialize the base structure. */
 105         /* What type of endpoint are we?  */
 106         ep->base.type = SCTP_EP_TYPE_SOCKET;
 107
 108         /* Initialize the basic object fields. */
 109         refcount_set(&ep->base.refcnt, 1);
 110         ep->base.dead = false;
 111
 112         /* Create an input queue.  */
 113         sctp_inq_init(&ep->base.inqueue);
 114
 115         /* Set its top-half handler */
 116         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
 117
 118         /* Initialize the bind addr area */
 119         sctp_bind_addr_init(&ep->base.bind_addr, 0);
 120
 121         /* Create the lists of associations.  */
 122         INIT_LIST_HEAD(&ep->asocs);
 123
 124         /* Use SCTP specific send buffer space queues.  */
 125         ep->sndbuf_policy = net->sctp.sndbuf_policy;
 126
 127         sk->sk_data_ready = sctp_data_ready;
 128         sk->sk_write_space = sctp_write_space;
 129         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 130
 131         /* Get the receive buffer policy for this endpoint */
 132         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
 133
 134         /* Initialize the secret key used with cookie. */
 135         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
 136
 137         /* SCTP-AUTH extensions*/
 138         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
 139         null_key = sctp_auth_shkey_create(0, gfp);
 140         if (!null_key)
 141                 goto nomem_shkey;
 142
 143         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 144
 145         /* Add the null key to the endpoint shared keys list and
 146          * set the hmcas and chunks pointers.
 147          */
 148         ep->auth_hmacs_list = auth_hmacs;
 149         ep->auth_chunk_list = auth_chunks;
 150         ep->prsctp_enable = net->sctp.prsctp_enable;
 151         ep->reconf_enable = net->sctp.reconf_enable;
 152
 153         /* Remember who we are attached to.  */
 154         ep->base.sk = sk;
 155         sock_hold(ep->base.sk);
 156
 157         return ep;
 158
 159 nomem_shkey:
 160         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 161 nomem:
 162         /* Free all allocations */
 163         kfree(auth_hmacs);
 164         kfree(auth_chunks);
 165         kfree(ep->digest);
 166         return NULL;
 167
 168 }
 169
 170 /* Create a sctp_endpoint with all that boring stuff initialized.
 171  * Returns NULL if there isn't enough memory.
 172  */
 173 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 174 {
 175         struct sctp_endpoint *ep;
 176
 177         /* Build a local endpoint. */
 178         ep = kzalloc(sizeof(*ep), gfp);
 179         if (!ep)
 180                 goto fail;
 181
 182         if (!sctp_endpoint_init(ep, sk, gfp))
 183                 goto fail_init;
 184
 185         SCTP_DBG_OBJCNT_INC(ep);
 186         return ep;
 187
 188 fail_init:
 189         kfree(ep);
 190 fail:
 191         return NULL;
 192 }
 193
 194 /* Add an association to an endpoint.  */
 195 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 196                             struct sctp_association *asoc)
 197 {
 198         struct sock *sk = ep->base.sk;
 199
 200         /* If this is a temporary association, don't bother
 201          * since we'll be removing it shortly and don't
 202          * want anyone to find it anyway.
 203          */
 204         if (asoc->temp)
 205                 return;
 206
 207         /* Now just add it to our list of asocs */
 208         list_add_tail(&asoc->asocs, &ep->asocs);
 209
 210         /* Increment the backlog value for a TCP-style listening socket. */
 211         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 212                 sk->sk_ack_backlog++;
 213 }
 214
 215 /* Free the endpoint structure.  Delay cleanup until
 216  * all users have released their reference count on this structure.
 217  */
 218 void sctp_endpoint_free(struct sctp_endpoint *ep)
 219 {
 220         ep->base.dead = true;
 221
 222         inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
 223
 224         /* Unlink this endpoint, so we can't find it again! */
 225         sctp_unhash_endpoint(ep);
 226
 227         sctp_endpoint_put(ep);
 228 }
 229
 230 /* Final destructor for endpoint.  */
 231 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 232 {
 233         struct sock *sk;
 234
 235         if (unlikely(!ep->base.dead)) {
 236                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 237                 return;
 238         }
 239
 240         /* Free the digest buffer */
 241         kfree(ep->digest);
 242
 243         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 244          * chunks and hmacs arrays that were allocated
 245          */
 246         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 247         kfree(ep->auth_hmacs_list);
 248         kfree(ep->auth_chunk_list);
 249
 250         /* AUTH - Free any allocated HMAC transform containers */
 251         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 252
 253         /* Cleanup. */
 254         sctp_inq_free(&ep->base.inqueue);
 255         sctp_bind_addr_free(&ep->base.bind_addr);
 256
 257         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 258
 259         sk = ep->base.sk;
 260         /* Remove and free the port */
 261         if (sctp_sk(sk)->bind_hash)
 262                 sctp_put_port(sk);
 263
 264         sctp_sk(sk)->ep = NULL;
 265         /* Give up our hold on the sock */
 266         sock_put(sk);
 267
 268         kfree(ep);
 269         SCTP_DBG_OBJCNT_DEC(ep);
 270 }
 271
 272 /* Hold a reference to an endpoint. */
 273 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 274 {
 275         refcount_inc(&ep->base.refcnt);
 276 }
 277
 278 /* Release a reference to an endpoint and clean up if there are
 279  * no more references.
 280  */
 281 void sctp_endpoint_put(struct sctp_endpoint *ep)
 282 {
 283         if (refcount_dec_and_test(&ep->base.refcnt))
 284                 sctp_endpoint_destroy(ep);
 285 }
 286
 287 /* Is this the endpoint we are looking for?  */
 288 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 289                                                struct net *net,
 290                                                const union sctp_addr *laddr)
 291 {
 292         struct sctp_endpoint *retval = NULL;
 293
 294         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 295             net_eq(sock_net(ep->base.sk), net)) {
 296                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 297                                          sctp_sk(ep->base.sk)))
 298                         retval = ep;
 299         }
 300
 301         return retval;
 302 }
 303
 304 /* Find the association that goes with this chunk.
 305  * We lookup the transport from hashtable at first, then get association
 306  * through t->assoc.
 307  */
 308 struct sctp_association *sctp_endpoint_lookup_assoc(
 309         const struct sctp_endpoint *ep,
 310         const union sctp_addr *paddr,
 311         struct sctp_transport **transport)
 312 {
 313         struct sctp_association *asoc = NULL;
 314         struct sctp_transport *t;
 315
 316         *transport = NULL;
 317
 318         /* If the local port is not set, there can't be any associations
 319          * on this endpoint.
 320          */
 321         if (!ep->base.bind_addr.port)
 322                 return NULL;
 323
 324         rcu_read_lock();
 325         t = sctp_epaddr_lookup_transport(ep, paddr);
 326         if (!t)
 327                 goto out;
 328
 329         *transport = t;
 330         asoc = t->asoc;
 331 out:
 332         rcu_read_unlock();
 333         return asoc;
 334 }
 335
 336 /* Look for any peeled off association from the endpoint that matches the
 337  * given peer address.
 338  */
 339 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 340                                  const union sctp_addr *paddr)
 341 {
 342         struct sctp_sockaddr_entry *addr;
 343         struct sctp_bind_addr *bp;
 344         struct net *net = sock_net(ep->base.sk);
 345
 346         bp = &ep->base.bind_addr;
 347         /* This function is called with the socket lock held,
 348          * so the address_list can not change.
 349          */
 350         list_for_each_entry(addr, &bp->address_list, list) {
 351                 if (sctp_has_association(net, &addr->a, paddr))
 352                         return true;
 353         }
 354
 355         return false;
 356 }
 357
 358 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 359  * This may be called on BH or task time.
 360  */
 361 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 362 {
 363         struct sctp_endpoint *ep =
 364                 container_of(work, struct sctp_endpoint,
 365                              base.inqueue.immediate);
 366         struct sctp_association *asoc;
 367         struct sock *sk;
 368         struct net *net;
 369         struct sctp_transport *transport;
 370         struct sctp_chunk *chunk;
 371         struct sctp_inq *inqueue;
 372         union sctp_subtype subtype;
 373         enum sctp_state state;
 374         int error = 0;
 375         int first_time = 1;     /* is this the first time through the loop */
 376
 377         if (ep->base.dead)
 378                 return;
 379
 380         asoc = NULL;
 381         inqueue = &ep->base.inqueue;
 382         sk = ep->base.sk;
 383         net = sock_net(sk);
 384
 385         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 386                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 387
 388                 /* If the first chunk in the packet is AUTH, do special
 389                  * processing specified in Section 6.3 of SCTP-AUTH spec
 390                  */
 391                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 392                         struct sctp_chunkhdr *next_hdr;
 393
 394                         next_hdr = sctp_inq_peek(inqueue);
 395                         if (!next_hdr)
 396                                 goto normal;
 397
 398                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 399                          * chunk while saving a pointer to it so we can do
 400                          * Authentication later (during cookie-echo
 401                          * processing).
 402                          */
 403                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 404                                 chunk->auth_chunk = skb_clone(chunk->skb,
 405                                                                 GFP_ATOMIC);
 406                                 chunk->auth = 1;
 407                                 continue;
 408                         }
 409                 }
 410 normal:
 411                 /* We might have grown an association since last we
 412                  * looked, so try again.
 413                  *
 414                  * This happens when we've just processed our
 415                  * COOKIE-ECHO chunk.
 416                  */
 417                 if (NULL == chunk->asoc) {
 418                         asoc = sctp_endpoint_lookup_assoc(ep,
 419                                                           sctp_source(chunk),
 420                                                           &transport);
 421                         chunk->asoc = asoc;
 422                         chunk->transport = transport;
 423                 }
 424
 425                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 426                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 427                         continue;
 428
 429                 /* Remember where the last DATA chunk came from so we
 430                  * know where to send the SACK.
 431                  */
 432                 if (asoc && sctp_chunk_is_data(chunk))
 433                         asoc->peer.last_data_from = chunk->transport;
 434                 else {
 435                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 436                         if (asoc)
 437                                 asoc->stats.ictrlchunks++;
 438                 }
 439
 440                 if (chunk->transport)
 441                         chunk->transport->last_time_heard = ktime_get();
 442
 443                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 444                                    ep, asoc, chunk, GFP_ATOMIC);
 445
 446                 if (error && chunk)
 447                         chunk->pdiscard = 1;
 448
 449                 /* Check to see if the endpoint is freed in response to
 450                  * the incoming chunk. If so, get out of the while loop.
 451                  */
 452                 if (!sctp_sk(sk)->ep)
 453                         break;
 454
 455                 if (first_time)
 456                         first_time = 0;
 457         }
 458 }