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_shared_key *null_key;
  47
  48         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  49         if (!ep->digest)
  50                 return NULL;
  51
  52         ep->asconf_enable = net->sctp.addip_enable;
  53         ep->auth_enable = net->sctp.auth_enable;
  54         if (ep->auth_enable) {
  55                 if (sctp_auth_init(ep, gfp))
  56                         goto nomem;
  57                 if (ep->asconf_enable) {
  58                         sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF);
  59                         sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF_ACK);
  60                 }
  61         }
  62
  63         /* Initialize the base structure. */
  64         /* What type of endpoint are we?  */
  65         ep->base.type = SCTP_EP_TYPE_SOCKET;
  66
  67         /* Initialize the basic object fields. */
  68         refcount_set(&ep->base.refcnt, 1);
  69         ep->base.dead = false;
  70
  71         /* Create an input queue.  */
  72         sctp_inq_init(&ep->base.inqueue);
  73
  74         /* Set its top-half handler */
  75         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
  76
  77         /* Initialize the bind addr area */
  78         sctp_bind_addr_init(&ep->base.bind_addr, 0);
  79
  80         /* Create the lists of associations.  */
  81         INIT_LIST_HEAD(&ep->asocs);
  82
  83         /* Use SCTP specific send buffer space queues.  */
  84         ep->sndbuf_policy = net->sctp.sndbuf_policy;
  85
  86         sk->sk_data_ready = sctp_data_ready;
  87         sk->sk_write_space = sctp_write_space;
  88         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
  89
  90         /* Get the receive buffer policy for this endpoint */
  91         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
  92
  93         /* Initialize the secret key used with cookie. */
  94         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
  95
  96         /* SCTP-AUTH extensions*/
  97         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
  98         null_key = sctp_auth_shkey_create(0, gfp);
  99         if (!null_key)
 100                 goto nomem_shkey;
 101
 102         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 103
 104         /* Add the null key to the endpoint shared keys list and
 105          * set the hmcas and chunks pointers.
 106          */
 107         ep->prsctp_enable = net->sctp.prsctp_enable;
 108         ep->reconf_enable = net->sctp.reconf_enable;
 109         ep->ecn_enable = net->sctp.ecn_enable;
 110
 111         /* Remember who we are attached to.  */
 112         ep->base.sk = sk;
 113         ep->base.net = sock_net(sk);
 114         sock_hold(ep->base.sk);
 115
 116         return ep;
 117
 118 nomem_shkey:
 119         sctp_auth_free(ep);
 120 nomem:
 121         kfree(ep->digest);
 122         return NULL;
 123
 124 }
 125
 126 /* Create a sctp_endpoint with all that boring stuff initialized.
 127  * Returns NULL if there isn't enough memory.
 128  */
 129 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 130 {
 131         struct sctp_endpoint *ep;
 132
 133         /* Build a local endpoint. */
 134         ep = kzalloc(sizeof(*ep), gfp);
 135         if (!ep)
 136                 goto fail;
 137
 138         if (!sctp_endpoint_init(ep, sk, gfp))
 139                 goto fail_init;
 140
 141         SCTP_DBG_OBJCNT_INC(ep);
 142         return ep;
 143
 144 fail_init:
 145         kfree(ep);
 146 fail:
 147         return NULL;
 148 }
 149
 150 /* Add an association to an endpoint.  */
 151 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 152                             struct sctp_association *asoc)
 153 {
 154         struct sock *sk = ep->base.sk;
 155
 156         /* If this is a temporary association, don't bother
 157          * since we'll be removing it shortly and don't
 158          * want anyone to find it anyway.
 159          */
 160         if (asoc->temp)
 161                 return;
 162
 163         /* Now just add it to our list of asocs */
 164         list_add_tail(&asoc->asocs, &ep->asocs);
 165
 166         /* Increment the backlog value for a TCP-style listening socket. */
 167         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 168                 sk_acceptq_added(sk);
 169 }
 170
 171 /* Free the endpoint structure.  Delay cleanup until
 172  * all users have released their reference count on this structure.
 173  */
 174 void sctp_endpoint_free(struct sctp_endpoint *ep)
 175 {
 176         ep->base.dead = true;
 177
 178         inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
 179
 180         /* Unlink this endpoint, so we can't find it again! */
 181         sctp_unhash_endpoint(ep);
 182
 183         sctp_endpoint_put(ep);
 184 }
 185
 186 /* Final destructor for endpoint.  */
 187 static void sctp_endpoint_destroy_rcu(struct rcu_head *head)
 188 {
 189         struct sctp_endpoint *ep = container_of(head, struct sctp_endpoint, rcu);
 190         struct sock *sk = ep->base.sk;
 191
 192         sctp_sk(sk)->ep = NULL;
 193         sock_put(sk);
 194
 195         kfree(ep);
 196         SCTP_DBG_OBJCNT_DEC(ep);
 197 }
 198
 199 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 200 {
 201         struct sock *sk;
 202
 203         if (unlikely(!ep->base.dead)) {
 204                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 205                 return;
 206         }
 207
 208         /* Free the digest buffer */
 209         kfree(ep->digest);
 210
 211         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 212          * chunks and hmacs arrays that were allocated
 213          */
 214         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 215         sctp_auth_free(ep);
 216
 217         /* Cleanup. */
 218         sctp_inq_free(&ep->base.inqueue);
 219         sctp_bind_addr_free(&ep->base.bind_addr);
 220
 221         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 222
 223         sk = ep->base.sk;
 224         /* Remove and free the port */
 225         if (sctp_sk(sk)->bind_hash)
 226                 sctp_put_port(sk);
 227
 228         call_rcu(&ep->rcu, sctp_endpoint_destroy_rcu);
 229 }
 230
 231 /* Hold a reference to an endpoint. */
 232 int sctp_endpoint_hold(struct sctp_endpoint *ep)
 233 {
 234         return refcount_inc_not_zero(&ep->base.refcnt);
 235 }
 236
 237 /* Release a reference to an endpoint and clean up if there are
 238  * no more references.
 239  */
 240 void sctp_endpoint_put(struct sctp_endpoint *ep)
 241 {
 242         if (refcount_dec_and_test(&ep->base.refcnt))
 243                 sctp_endpoint_destroy(ep);
 244 }
 245
 246 /* Is this the endpoint we are looking for?  */
 247 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 248                                                struct net *net,
 249                                                const union sctp_addr *laddr,
 250                                                int dif, int sdif)
 251 {
 252         int bound_dev_if = READ_ONCE(ep->base.sk->sk_bound_dev_if);
 253         struct sctp_endpoint *retval = NULL;
 254
 255         if (net_eq(ep->base.net, net) &&
 256             sctp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif) &&
 257             (htons(ep->base.bind_addr.port) == laddr->v4.sin_port)) {
 258                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 259                                          sctp_sk(ep->base.sk)))
 260                         retval = ep;
 261         }
 262
 263         return retval;
 264 }
 265
 266 /* Find the association that goes with this chunk.
 267  * We lookup the transport from hashtable at first, then get association
 268  * through t->assoc.
 269  */
 270 struct sctp_association *sctp_endpoint_lookup_assoc(
 271         const struct sctp_endpoint *ep,
 272         const union sctp_addr *paddr,
 273         struct sctp_transport **transport)
 274 {
 275         struct sctp_association *asoc = NULL;
 276         struct sctp_transport *t;
 277
 278         *transport = NULL;
 279
 280         /* If the local port is not set, there can't be any associations
 281          * on this endpoint.
 282          */
 283         if (!ep->base.bind_addr.port)
 284                 return NULL;
 285
 286         rcu_read_lock();
 287         t = sctp_epaddr_lookup_transport(ep, paddr);
 288         if (!t)
 289                 goto out;
 290
 291         *transport = t;
 292         asoc = t->asoc;
 293 out:
 294         rcu_read_unlock();
 295         return asoc;
 296 }
 297
 298 /* Look for any peeled off association from the endpoint that matches the
 299  * given peer address.
 300  */
 301 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 302                                  const union sctp_addr *paddr)
 303 {
 304         int bound_dev_if = READ_ONCE(ep->base.sk->sk_bound_dev_if);
 305         struct sctp_sockaddr_entry *addr;
 306         struct net *net = ep->base.net;
 307         struct sctp_bind_addr *bp;
 308
 309         bp = &ep->base.bind_addr;
 310         /* This function is called with the socket lock held,
 311          * so the address_list can not change.
 312          */
 313         list_for_each_entry(addr, &bp->address_list, list) {
 314                 if (sctp_has_association(net, &addr->a, paddr,
 315                                          bound_dev_if, bound_dev_if))
 316                         return true;
 317         }
 318
 319         return false;
 320 }
 321
 322 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 323  * This may be called on BH or task time.
 324  */
 325 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 326 {
 327         struct sctp_endpoint *ep =
 328                 container_of(work, struct sctp_endpoint,
 329                              base.inqueue.immediate);
 330         struct sctp_association *asoc;
 331         struct sock *sk;
 332         struct net *net;
 333         struct sctp_transport *transport;
 334         struct sctp_chunk *chunk;
 335         struct sctp_inq *inqueue;
 336         union sctp_subtype subtype;
 337         enum sctp_state state;
 338         int error = 0;
 339         int first_time = 1;     /* is this the first time through the loop */
 340
 341         if (ep->base.dead)
 342                 return;
 343
 344         asoc = NULL;
 345         inqueue = &ep->base.inqueue;
 346         sk = ep->base.sk;
 347         net = sock_net(sk);
 348
 349         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 350                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 351
 352                 /* If the first chunk in the packet is AUTH, do special
 353                  * processing specified in Section 6.3 of SCTP-AUTH spec
 354                  */
 355                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 356                         struct sctp_chunkhdr *next_hdr;
 357
 358                         next_hdr = sctp_inq_peek(inqueue);
 359                         if (!next_hdr)
 360                                 goto normal;
 361
 362                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 363                          * chunk while saving a pointer to it so we can do
 364                          * Authentication later (during cookie-echo
 365                          * processing).
 366                          */
 367                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 368                                 chunk->auth_chunk = skb_clone(chunk->skb,
 369                                                                 GFP_ATOMIC);
 370                                 chunk->auth = 1;
 371                                 continue;
 372                         }
 373                 }
 374 normal:
 375                 /* We might have grown an association since last we
 376                  * looked, so try again.
 377                  *
 378                  * This happens when we've just processed our
 379                  * COOKIE-ECHO chunk.
 380                  */
 381                 if (NULL == chunk->asoc) {
 382                         asoc = sctp_endpoint_lookup_assoc(ep,
 383                                                           sctp_source(chunk),
 384                                                           &transport);
 385                         chunk->asoc = asoc;
 386                         chunk->transport = transport;
 387                 }
 388
 389                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 390                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 391                         continue;
 392
 393                 /* Remember where the last DATA chunk came from so we
 394                  * know where to send the SACK.
 395                  */
 396                 if (asoc && sctp_chunk_is_data(chunk))
 397                         asoc->peer.last_data_from = chunk->transport;
 398                 else {
 399                         SCTP_INC_STATS(ep->base.net, SCTP_MIB_INCTRLCHUNKS);
 400                         if (asoc)
 401                                 asoc->stats.ictrlchunks++;
 402                 }
 403
 404                 if (chunk->transport)
 405                         chunk->transport->last_time_heard = ktime_get();
 406
 407                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 408                                    ep, asoc, chunk, GFP_ATOMIC);
 409
 410                 if (error && chunk)
 411                         chunk->pdiscard = 1;
 412
 413                 /* Check to see if the endpoint is freed in response to
 414                  * the incoming chunk. If so, get out of the while loop.
 415                  */
 416                 if (!sctp_sk(sk)->ep)
 417                         break;
 418
 419                 if (first_time)
 420                         first_time = 0;
 421         }
 422 }