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 /* Remember who we are attached to. */ 122 ep->base.sk = sk; 123 sock_hold(ep->base.sk); 124 125 /* Create the lists of associations. */ 126 INIT_LIST_HEAD(&ep->asocs); 127 128 /* Use SCTP specific send buffer space queues. */ 129 ep->sndbuf_policy = net->sctp.sndbuf_policy; 130 131 sk->sk_data_ready = sctp_data_ready; 132 sk->sk_write_space = sctp_write_space; 133 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 134 135 /* Get the receive buffer policy for this endpoint */ 136 ep->rcvbuf_policy = net->sctp.rcvbuf_policy; 137 138 /* Initialize the secret key used with cookie. */ 139 get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); 140 141 /* SCTP-AUTH extensions*/ 142 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 143 null_key = sctp_auth_shkey_create(0, gfp); 144 if (!null_key) 145 goto nomem_shkey; 146 147 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 148 149 /* Add the null key to the endpoint shared keys list and 150 * set the hmcas and chunks pointers. 151 */ 152 ep->auth_hmacs_list = auth_hmacs; 153 ep->auth_chunk_list = auth_chunks; 154 ep->prsctp_enable = net->sctp.prsctp_enable; 155 ep->reconf_enable = net->sctp.reconf_enable; 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 } 459