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(struct sctp_endpoint *ep)
 188 {
 189         struct sock *sk;
 190
 191         if (unlikely(!ep->base.dead)) {
 192                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 193                 return;
 194         }
 195
 196         /* Free the digest buffer */
 197         kfree(ep->digest);
 198
 199         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 200          * chunks and hmacs arrays that were allocated
 201          */
 202         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 203         sctp_auth_free(ep);
 204
 205         /* Cleanup. */
 206         sctp_inq_free(&ep->base.inqueue);
 207         sctp_bind_addr_free(&ep->base.bind_addr);
 208
 209         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 210
 211         sk = ep->base.sk;
 212         /* Remove and free the port */
 213         if (sctp_sk(sk)->bind_hash)
 214                 sctp_put_port(sk);
 215
 216         sctp_sk(sk)->ep = NULL;
 217         /* Give up our hold on the sock */
 218         sock_put(sk);
 219
 220         kfree(ep);
 221         SCTP_DBG_OBJCNT_DEC(ep);
 222 }
 223
 224 /* Hold a reference to an endpoint. */
 225 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 226 {
 227         refcount_inc(&ep->base.refcnt);
 228 }
 229
 230 /* Release a reference to an endpoint and clean up if there are
 231  * no more references.
 232  */
 233 void sctp_endpoint_put(struct sctp_endpoint *ep)
 234 {
 235         if (refcount_dec_and_test(&ep->base.refcnt))
 236                 sctp_endpoint_destroy(ep);
 237 }
 238
 239 /* Is this the endpoint we are looking for?  */
 240 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 241                                                struct net *net,
 242                                                const union sctp_addr *laddr)
 243 {
 244         struct sctp_endpoint *retval = NULL;
 245
 246         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 247             net_eq(ep->base.net, net)) {
 248                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 249                                          sctp_sk(ep->base.sk)))
 250                         retval = ep;
 251         }
 252
 253         return retval;
 254 }
 255
 256 /* Find the association that goes with this chunk.
 257  * We lookup the transport from hashtable at first, then get association
 258  * through t->assoc.
 259  */
 260 struct sctp_association *sctp_endpoint_lookup_assoc(
 261         const struct sctp_endpoint *ep,
 262         const union sctp_addr *paddr,
 263         struct sctp_transport **transport)
 264 {
 265         struct sctp_association *asoc = NULL;
 266         struct sctp_transport *t;
 267
 268         *transport = NULL;
 269
 270         /* If the local port is not set, there can't be any associations
 271          * on this endpoint.
 272          */
 273         if (!ep->base.bind_addr.port)
 274                 return NULL;
 275
 276         rcu_read_lock();
 277         t = sctp_epaddr_lookup_transport(ep, paddr);
 278         if (!t)
 279                 goto out;
 280
 281         *transport = t;
 282         asoc = t->asoc;
 283 out:
 284         rcu_read_unlock();
 285         return asoc;
 286 }
 287
 288 /* Look for any peeled off association from the endpoint that matches the
 289  * given peer address.
 290  */
 291 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 292                                  const union sctp_addr *paddr)
 293 {
 294         struct sctp_sockaddr_entry *addr;
 295         struct net *net = ep->base.net;
 296         struct sctp_bind_addr *bp;
 297
 298         bp = &ep->base.bind_addr;
 299         /* This function is called with the socket lock held,
 300          * so the address_list can not change.
 301          */
 302         list_for_each_entry(addr, &bp->address_list, list) {
 303                 if (sctp_has_association(net, &addr->a, paddr))
 304                         return true;
 305         }
 306
 307         return false;
 308 }
 309
 310 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 311  * This may be called on BH or task time.
 312  */
 313 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 314 {
 315         struct sctp_endpoint *ep =
 316                 container_of(work, struct sctp_endpoint,
 317                              base.inqueue.immediate);
 318         struct sctp_association *asoc;
 319         struct sock *sk;
 320         struct net *net;
 321         struct sctp_transport *transport;
 322         struct sctp_chunk *chunk;
 323         struct sctp_inq *inqueue;
 324         union sctp_subtype subtype;
 325         enum sctp_state state;
 326         int error = 0;
 327         int first_time = 1;     /* is this the first time through the loop */
 328
 329         if (ep->base.dead)
 330                 return;
 331
 332         asoc = NULL;
 333         inqueue = &ep->base.inqueue;
 334         sk = ep->base.sk;
 335         net = sock_net(sk);
 336
 337         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 338                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 339
 340                 /* If the first chunk in the packet is AUTH, do special
 341                  * processing specified in Section 6.3 of SCTP-AUTH spec
 342                  */
 343                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 344                         struct sctp_chunkhdr *next_hdr;
 345
 346                         next_hdr = sctp_inq_peek(inqueue);
 347                         if (!next_hdr)
 348                                 goto normal;
 349
 350                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 351                          * chunk while saving a pointer to it so we can do
 352                          * Authentication later (during cookie-echo
 353                          * processing).
 354                          */
 355                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 356                                 chunk->auth_chunk = skb_clone(chunk->skb,
 357                                                                 GFP_ATOMIC);
 358                                 chunk->auth = 1;
 359                                 continue;
 360                         }
 361                 }
 362 normal:
 363                 /* We might have grown an association since last we
 364                  * looked, so try again.
 365                  *
 366                  * This happens when we've just processed our
 367                  * COOKIE-ECHO chunk.
 368                  */
 369                 if (NULL == chunk->asoc) {
 370                         asoc = sctp_endpoint_lookup_assoc(ep,
 371                                                           sctp_source(chunk),
 372                                                           &transport);
 373                         chunk->asoc = asoc;
 374                         chunk->transport = transport;
 375                 }
 376
 377                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 378                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 379                         continue;
 380
 381                 /* Remember where the last DATA chunk came from so we
 382                  * know where to send the SACK.
 383                  */
 384                 if (asoc && sctp_chunk_is_data(chunk))
 385                         asoc->peer.last_data_from = chunk->transport;
 386                 else {
 387                         SCTP_INC_STATS(ep->base.net, SCTP_MIB_INCTRLCHUNKS);
 388                         if (asoc)
 389                                 asoc->stats.ictrlchunks++;
 390                 }
 391
 392                 if (chunk->transport)
 393                         chunk->transport->last_time_heard = ktime_get();
 394
 395                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 396                                    ep, asoc, chunk, GFP_ATOMIC);
 397
 398                 if (error && chunk)
 399                         chunk->pdiscard = 1;
 400
 401                 /* Check to see if the endpoint is freed in response to
 402                  * the incoming chunk. If so, get out of the while loop.
 403                  */
 404                 if (!sctp_sk(sk)->ep)
 405                         break;
 406
 407                 if (first_time)
 408                         first_time = 0;
 409         }
 410 }