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->asconf_enable = net->sctp.addip_enable; 56 ep->auth_enable = net->sctp.auth_enable; 57 if (ep->auth_enable) { 58 /* Allocate space for HMACS and CHUNKS authentication 59 * variables. There are arrays that we encode directly 60 * into parameters to make the rest of the operations easier. 61 */ 62 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids, 63 SCTP_AUTH_NUM_HMACS), gfp); 64 if (!auth_hmacs) 65 goto nomem; 66 67 auth_chunks = kzalloc(sizeof(*auth_chunks) + 68 SCTP_NUM_CHUNK_TYPES, gfp); 69 if (!auth_chunks) 70 goto nomem; 71 72 /* Initialize the HMACS parameter. 73 * SCTP-AUTH: Section 3.3 74 * Every endpoint supporting SCTP chunk authentication MUST 75 * support the HMAC based on the SHA-1 algorithm. 76 */ 77 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO; 78 auth_hmacs->param_hdr.length = 79 htons(sizeof(struct sctp_paramhdr) + 2); 80 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1); 81 82 /* Initialize the CHUNKS parameter */ 83 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS; 84 auth_chunks->param_hdr.length = 85 htons(sizeof(struct sctp_paramhdr)); 86 87 /* If the Add-IP functionality is enabled, we must 88 * authenticate, ASCONF and ASCONF-ACK chunks 89 */ 90 if (ep->asconf_enable) { 91 auth_chunks->chunks[0] = SCTP_CID_ASCONF; 92 auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK; 93 auth_chunks->param_hdr.length = 94 htons(sizeof(struct sctp_paramhdr) + 2); 95 } 96 97 /* Allocate and initialize transorms arrays for supported 98 * HMACs. 99 */ 100 err = sctp_auth_init_hmacs(ep, gfp); 101 if (err) 102 goto nomem; 103 } 104 105 /* Initialize the base structure. */ 106 /* What type of endpoint are we? */ 107 ep->base.type = SCTP_EP_TYPE_SOCKET; 108 109 /* Initialize the basic object fields. */ 110 refcount_set(&ep->base.refcnt, 1); 111 ep->base.dead = false; 112 113 /* Create an input queue. */ 114 sctp_inq_init(&ep->base.inqueue); 115 116 /* Set its top-half handler */ 117 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); 118 119 /* Initialize the bind addr area */ 120 sctp_bind_addr_init(&ep->base.bind_addr, 0); 121 122 /* Create the lists of associations. */ 123 INIT_LIST_HEAD(&ep->asocs); 124 125 /* Use SCTP specific send buffer space queues. */ 126 ep->sndbuf_policy = net->sctp.sndbuf_policy; 127 128 sk->sk_data_ready = sctp_data_ready; 129 sk->sk_write_space = sctp_write_space; 130 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 131 132 /* Get the receive buffer policy for this endpoint */ 133 ep->rcvbuf_policy = net->sctp.rcvbuf_policy; 134 135 /* Initialize the secret key used with cookie. */ 136 get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); 137 138 /* SCTP-AUTH extensions*/ 139 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 140 null_key = sctp_auth_shkey_create(0, gfp); 141 if (!null_key) 142 goto nomem_shkey; 143 144 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 145 146 /* Add the null key to the endpoint shared keys list and 147 * set the hmcas and chunks pointers. 148 */ 149 ep->auth_hmacs_list = auth_hmacs; 150 ep->auth_chunk_list = auth_chunks; 151 ep->prsctp_enable = net->sctp.prsctp_enable; 152 ep->reconf_enable = net->sctp.reconf_enable; 153 154 /* Remember who we are attached to. */ 155 ep->base.sk = sk; 156 sock_hold(ep->base.sk); 157 158 return ep; 159 160 nomem_shkey: 161 sctp_auth_destroy_hmacs(ep->auth_hmacs); 162 nomem: 163 /* Free all allocations */ 164 kfree(auth_hmacs); 165 kfree(auth_chunks); 166 kfree(ep->digest); 167 return NULL; 168 169 } 170 171 /* Create a sctp_endpoint with all that boring stuff initialized. 172 * Returns NULL if there isn't enough memory. 173 */ 174 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 175 { 176 struct sctp_endpoint *ep; 177 178 /* Build a local endpoint. */ 179 ep = kzalloc(sizeof(*ep), gfp); 180 if (!ep) 181 goto fail; 182 183 if (!sctp_endpoint_init(ep, sk, gfp)) 184 goto fail_init; 185 186 SCTP_DBG_OBJCNT_INC(ep); 187 return ep; 188 189 fail_init: 190 kfree(ep); 191 fail: 192 return NULL; 193 } 194 195 /* Add an association to an endpoint. */ 196 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 197 struct sctp_association *asoc) 198 { 199 struct sock *sk = ep->base.sk; 200 201 /* If this is a temporary association, don't bother 202 * since we'll be removing it shortly and don't 203 * want anyone to find it anyway. 204 */ 205 if (asoc->temp) 206 return; 207 208 /* Now just add it to our list of asocs */ 209 list_add_tail(&asoc->asocs, &ep->asocs); 210 211 /* Increment the backlog value for a TCP-style listening socket. */ 212 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 213 sk->sk_ack_backlog++; 214 } 215 216 /* Free the endpoint structure. Delay cleanup until 217 * all users have released their reference count on this structure. 218 */ 219 void sctp_endpoint_free(struct sctp_endpoint *ep) 220 { 221 ep->base.dead = true; 222 223 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); 224 225 /* Unlink this endpoint, so we can't find it again! */ 226 sctp_unhash_endpoint(ep); 227 228 sctp_endpoint_put(ep); 229 } 230 231 /* Final destructor for endpoint. */ 232 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 233 { 234 struct sock *sk; 235 236 if (unlikely(!ep->base.dead)) { 237 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 238 return; 239 } 240 241 /* Free the digest buffer */ 242 kfree(ep->digest); 243 244 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 245 * chunks and hmacs arrays that were allocated 246 */ 247 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 248 kfree(ep->auth_hmacs_list); 249 kfree(ep->auth_chunk_list); 250 251 /* AUTH - Free any allocated HMAC transform containers */ 252 sctp_auth_destroy_hmacs(ep->auth_hmacs); 253 254 /* Cleanup. */ 255 sctp_inq_free(&ep->base.inqueue); 256 sctp_bind_addr_free(&ep->base.bind_addr); 257 258 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 259 260 sk = ep->base.sk; 261 /* Remove and free the port */ 262 if (sctp_sk(sk)->bind_hash) 263 sctp_put_port(sk); 264 265 sctp_sk(sk)->ep = NULL; 266 /* Give up our hold on the sock */ 267 sock_put(sk); 268 269 kfree(ep); 270 SCTP_DBG_OBJCNT_DEC(ep); 271 } 272 273 /* Hold a reference to an endpoint. */ 274 void sctp_endpoint_hold(struct sctp_endpoint *ep) 275 { 276 refcount_inc(&ep->base.refcnt); 277 } 278 279 /* Release a reference to an endpoint and clean up if there are 280 * no more references. 281 */ 282 void sctp_endpoint_put(struct sctp_endpoint *ep) 283 { 284 if (refcount_dec_and_test(&ep->base.refcnt)) 285 sctp_endpoint_destroy(ep); 286 } 287 288 /* Is this the endpoint we are looking for? */ 289 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 290 struct net *net, 291 const union sctp_addr *laddr) 292 { 293 struct sctp_endpoint *retval = NULL; 294 295 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 296 net_eq(sock_net(ep->base.sk), net)) { 297 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 298 sctp_sk(ep->base.sk))) 299 retval = ep; 300 } 301 302 return retval; 303 } 304 305 /* Find the association that goes with this chunk. 306 * We lookup the transport from hashtable at first, then get association 307 * through t->assoc. 308 */ 309 struct sctp_association *sctp_endpoint_lookup_assoc( 310 const struct sctp_endpoint *ep, 311 const union sctp_addr *paddr, 312 struct sctp_transport **transport) 313 { 314 struct sctp_association *asoc = NULL; 315 struct sctp_transport *t; 316 317 *transport = NULL; 318 319 /* If the local port is not set, there can't be any associations 320 * on this endpoint. 321 */ 322 if (!ep->base.bind_addr.port) 323 return NULL; 324 325 rcu_read_lock(); 326 t = sctp_epaddr_lookup_transport(ep, paddr); 327 if (!t) 328 goto out; 329 330 *transport = t; 331 asoc = t->asoc; 332 out: 333 rcu_read_unlock(); 334 return asoc; 335 } 336 337 /* Look for any peeled off association from the endpoint that matches the 338 * given peer address. 339 */ 340 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 341 const union sctp_addr *paddr) 342 { 343 struct sctp_sockaddr_entry *addr; 344 struct sctp_bind_addr *bp; 345 struct net *net = sock_net(ep->base.sk); 346 347 bp = &ep->base.bind_addr; 348 /* This function is called with the socket lock held, 349 * so the address_list can not change. 350 */ 351 list_for_each_entry(addr, &bp->address_list, list) { 352 if (sctp_has_association(net, &addr->a, paddr)) 353 return true; 354 } 355 356 return false; 357 } 358 359 /* Do delayed input processing. This is scheduled by sctp_rcv(). 360 * This may be called on BH or task time. 361 */ 362 static void sctp_endpoint_bh_rcv(struct work_struct *work) 363 { 364 struct sctp_endpoint *ep = 365 container_of(work, struct sctp_endpoint, 366 base.inqueue.immediate); 367 struct sctp_association *asoc; 368 struct sock *sk; 369 struct net *net; 370 struct sctp_transport *transport; 371 struct sctp_chunk *chunk; 372 struct sctp_inq *inqueue; 373 union sctp_subtype subtype; 374 enum sctp_state state; 375 int error = 0; 376 int first_time = 1; /* is this the first time through the loop */ 377 378 if (ep->base.dead) 379 return; 380 381 asoc = NULL; 382 inqueue = &ep->base.inqueue; 383 sk = ep->base.sk; 384 net = sock_net(sk); 385 386 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 387 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 388 389 /* If the first chunk in the packet is AUTH, do special 390 * processing specified in Section 6.3 of SCTP-AUTH spec 391 */ 392 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 393 struct sctp_chunkhdr *next_hdr; 394 395 next_hdr = sctp_inq_peek(inqueue); 396 if (!next_hdr) 397 goto normal; 398 399 /* If the next chunk is COOKIE-ECHO, skip the AUTH 400 * chunk while saving a pointer to it so we can do 401 * Authentication later (during cookie-echo 402 * processing). 403 */ 404 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 405 chunk->auth_chunk = skb_clone(chunk->skb, 406 GFP_ATOMIC); 407 chunk->auth = 1; 408 continue; 409 } 410 } 411 normal: 412 /* We might have grown an association since last we 413 * looked, so try again. 414 * 415 * This happens when we've just processed our 416 * COOKIE-ECHO chunk. 417 */ 418 if (NULL == chunk->asoc) { 419 asoc = sctp_endpoint_lookup_assoc(ep, 420 sctp_source(chunk), 421 &transport); 422 chunk->asoc = asoc; 423 chunk->transport = transport; 424 } 425 426 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 427 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 428 continue; 429 430 /* Remember where the last DATA chunk came from so we 431 * know where to send the SACK. 432 */ 433 if (asoc && sctp_chunk_is_data(chunk)) 434 asoc->peer.last_data_from = chunk->transport; 435 else { 436 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 437 if (asoc) 438 asoc->stats.ictrlchunks++; 439 } 440 441 if (chunk->transport) 442 chunk->transport->last_time_heard = ktime_get(); 443 444 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 445 ep, asoc, chunk, GFP_ATOMIC); 446 447 if (error && chunk) 448 chunk->pdiscard = 1; 449 450 /* Check to see if the endpoint is freed in response to 451 * the incoming chunk. If so, get out of the while loop. 452 */ 453 if (!sctp_sk(sk)->ep) 454 break; 455 456 if (first_time) 457 first_time = 0; 458 } 459 } 460