xref: /linux/net/sctp/endpointola.c (revision 6eb2fb3170549737207974c2c6ad34bcc2f3025e)
1 /* SCTP kernel implementation
2  * Copyright (c) 1999-2000 Cisco, Inc.
3  * Copyright (c) 1999-2001 Motorola, Inc.
4  * Copyright (c) 2001-2002 International Business Machines, Corp.
5  * Copyright (c) 2001 Intel Corp.
6  * Copyright (c) 2001 Nokia, Inc.
7  * Copyright (c) 2001 La Monte H.P. Yarroll
8  *
9  * This file is part of the SCTP kernel implementation
10  *
11  * This abstraction represents an SCTP endpoint.
12  *
13  * The SCTP implementation is free software;
14  * you can redistribute it and/or modify it under the terms of
15  * the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  * The SCTP implementation is distributed in the hope that it
20  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21  *                 ************************
22  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23  * See the GNU General Public License for more details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with GNU CC; see the file COPYING.  If not, write to
27  * the Free Software Foundation, 59 Temple Place - Suite 330,
28  * Boston, MA 02111-1307, USA.
29  *
30  * Please send any bug reports or fixes you make to the
31  * email address(es):
32  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
33  *
34  * Or submit a bug report through the following website:
35  *    http://www.sf.net/projects/lksctp
36  *
37  * Written or modified by:
38  *    La Monte H.P. Yarroll <piggy@acm.org>
39  *    Karl Knutson <karl@athena.chicago.il.us>
40  *    Jon Grimm <jgrimm@austin.ibm.com>
41  *    Daisy Chang <daisyc@us.ibm.com>
42  *    Dajiang Zhang <dajiang.zhang@nokia.com>
43  *
44  * Any bugs reported given to us we will try to fix... any fixes shared will
45  * be incorporated into the next SCTP release.
46  */
47 
48 #include <linux/types.h>
49 #include <linux/slab.h>
50 #include <linux/in.h>
51 #include <linux/random.h>	/* get_random_bytes() */
52 #include <linux/crypto.h>
53 #include <net/sock.h>
54 #include <net/ipv6.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 
58 /* Forward declarations for internal helpers. */
59 static void sctp_endpoint_bh_rcv(struct work_struct *work);
60 
61 /*
62  * Initialize the base fields of the endpoint structure.
63  */
64 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
65 						struct sock *sk,
66 						gfp_t gfp)
67 {
68 	struct net *net = sock_net(sk);
69 	struct sctp_hmac_algo_param *auth_hmacs = NULL;
70 	struct sctp_chunks_param *auth_chunks = NULL;
71 	struct sctp_shared_key *null_key;
72 	int err;
73 
74 	ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
75 	if (!ep->digest)
76 		return NULL;
77 
78 	if (net->sctp.auth_enable) {
79 		/* Allocate space for HMACS and CHUNKS authentication
80 		 * variables.  There are arrays that we encode directly
81 		 * into parameters to make the rest of the operations easier.
82 		 */
83 		auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
84 				sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
85 		if (!auth_hmacs)
86 			goto nomem;
87 
88 		auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
89 					SCTP_NUM_CHUNK_TYPES, gfp);
90 		if (!auth_chunks)
91 			goto nomem;
92 
93 		/* Initialize the HMACS parameter.
94 		 * SCTP-AUTH: Section 3.3
95 		 *    Every endpoint supporting SCTP chunk authentication MUST
96 		 *    support the HMAC based on the SHA-1 algorithm.
97 		 */
98 		auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
99 		auth_hmacs->param_hdr.length =
100 					htons(sizeof(sctp_paramhdr_t) + 2);
101 		auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
102 
103 		/* Initialize the CHUNKS parameter */
104 		auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
105 		auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));
106 
107 		/* If the Add-IP functionality is enabled, we must
108 		 * authenticate, ASCONF and ASCONF-ACK chunks
109 		 */
110 		if (net->sctp.addip_enable) {
111 			auth_chunks->chunks[0] = SCTP_CID_ASCONF;
112 			auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
113 			auth_chunks->param_hdr.length =
114 					htons(sizeof(sctp_paramhdr_t) + 2);
115 		}
116 	}
117 
118 	/* Initialize the base structure. */
119 	/* What type of endpoint are we?  */
120 	ep->base.type = SCTP_EP_TYPE_SOCKET;
121 
122 	/* Initialize the basic object fields. */
123 	atomic_set(&ep->base.refcnt, 1);
124 	ep->base.dead = false;
125 
126 	/* Create an input queue.  */
127 	sctp_inq_init(&ep->base.inqueue);
128 
129 	/* Set its top-half handler */
130 	sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
131 
132 	/* Initialize the bind addr area */
133 	sctp_bind_addr_init(&ep->base.bind_addr, 0);
134 
135 	/* Remember who we are attached to.  */
136 	ep->base.sk = sk;
137 	sock_hold(ep->base.sk);
138 
139 	/* Create the lists of associations.  */
140 	INIT_LIST_HEAD(&ep->asocs);
141 
142 	/* Use SCTP specific send buffer space queues.  */
143 	ep->sndbuf_policy = net->sctp.sndbuf_policy;
144 
145 	sk->sk_data_ready = sctp_data_ready;
146 	sk->sk_write_space = sctp_write_space;
147 	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
148 
149 	/* Get the receive buffer policy for this endpoint */
150 	ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
151 
152 	/* Initialize the secret key used with cookie. */
153 	get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
154 
155 	/* SCTP-AUTH extensions*/
156 	INIT_LIST_HEAD(&ep->endpoint_shared_keys);
157 	null_key = sctp_auth_shkey_create(0, gfp);
158 	if (!null_key)
159 		goto nomem;
160 
161 	list_add(&null_key->key_list, &ep->endpoint_shared_keys);
162 
163 	/* Allocate and initialize transorms arrays for supported HMACs. */
164 	err = sctp_auth_init_hmacs(ep, gfp);
165 	if (err)
166 		goto nomem_hmacs;
167 
168 	/* Add the null key to the endpoint shared keys list and
169 	 * set the hmcas and chunks pointers.
170 	 */
171 	ep->auth_hmacs_list = auth_hmacs;
172 	ep->auth_chunk_list = auth_chunks;
173 
174 	return ep;
175 
176 nomem_hmacs:
177 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
178 nomem:
179 	/* Free all allocations */
180 	kfree(auth_hmacs);
181 	kfree(auth_chunks);
182 	kfree(ep->digest);
183 	return NULL;
184 
185 }
186 
187 /* Create a sctp_endpoint with all that boring stuff initialized.
188  * Returns NULL if there isn't enough memory.
189  */
190 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
191 {
192 	struct sctp_endpoint *ep;
193 
194 	/* Build a local endpoint. */
195 	ep = t_new(struct sctp_endpoint, gfp);
196 	if (!ep)
197 		goto fail;
198 	if (!sctp_endpoint_init(ep, sk, gfp))
199 		goto fail_init;
200 
201 	SCTP_DBG_OBJCNT_INC(ep);
202 	return ep;
203 
204 fail_init:
205 	kfree(ep);
206 fail:
207 	return NULL;
208 }
209 
210 /* Add an association to an endpoint.  */
211 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
212 			    struct sctp_association *asoc)
213 {
214 	struct sock *sk = ep->base.sk;
215 
216 	/* If this is a temporary association, don't bother
217 	 * since we'll be removing it shortly and don't
218 	 * want anyone to find it anyway.
219 	 */
220 	if (asoc->temp)
221 		return;
222 
223 	/* Now just add it to our list of asocs */
224 	list_add_tail(&asoc->asocs, &ep->asocs);
225 
226 	/* Increment the backlog value for a TCP-style listening socket. */
227 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
228 		sk->sk_ack_backlog++;
229 }
230 
231 /* Free the endpoint structure.  Delay cleanup until
232  * all users have released their reference count on this structure.
233  */
234 void sctp_endpoint_free(struct sctp_endpoint *ep)
235 {
236 	ep->base.dead = true;
237 
238 	ep->base.sk->sk_state = SCTP_SS_CLOSED;
239 
240 	/* Unlink this endpoint, so we can't find it again! */
241 	sctp_unhash_endpoint(ep);
242 
243 	sctp_endpoint_put(ep);
244 }
245 
246 /* Final destructor for endpoint.  */
247 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
248 {
249 	SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
250 
251 	/* Free up the HMAC transform. */
252 	crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
253 
254 	/* Free the digest buffer */
255 	kfree(ep->digest);
256 
257 	/* SCTP-AUTH: Free up AUTH releated data such as shared keys
258 	 * chunks and hmacs arrays that were allocated
259 	 */
260 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
261 	kfree(ep->auth_hmacs_list);
262 	kfree(ep->auth_chunk_list);
263 
264 	/* AUTH - Free any allocated HMAC transform containers */
265 	sctp_auth_destroy_hmacs(ep->auth_hmacs);
266 
267 	/* Cleanup. */
268 	sctp_inq_free(&ep->base.inqueue);
269 	sctp_bind_addr_free(&ep->base.bind_addr);
270 
271 	memset(ep->secret_key, 0, sizeof(ep->secret_key));
272 
273 	/* Remove and free the port */
274 	if (sctp_sk(ep->base.sk)->bind_hash)
275 		sctp_put_port(ep->base.sk);
276 
277 	/* Give up our hold on the sock. */
278 	if (ep->base.sk)
279 		sock_put(ep->base.sk);
280 
281 	kfree(ep);
282 	SCTP_DBG_OBJCNT_DEC(ep);
283 }
284 
285 /* Hold a reference to an endpoint. */
286 void sctp_endpoint_hold(struct sctp_endpoint *ep)
287 {
288 	atomic_inc(&ep->base.refcnt);
289 }
290 
291 /* Release a reference to an endpoint and clean up if there are
292  * no more references.
293  */
294 void sctp_endpoint_put(struct sctp_endpoint *ep)
295 {
296 	if (atomic_dec_and_test(&ep->base.refcnt))
297 		sctp_endpoint_destroy(ep);
298 }
299 
300 /* Is this the endpoint we are looking for?  */
301 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
302 					       struct net *net,
303 					       const union sctp_addr *laddr)
304 {
305 	struct sctp_endpoint *retval = NULL;
306 
307 	if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
308 	    net_eq(sock_net(ep->base.sk), net)) {
309 		if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
310 					 sctp_sk(ep->base.sk)))
311 			retval = ep;
312 	}
313 
314 	return retval;
315 }
316 
317 /* Find the association that goes with this chunk.
318  * We do a linear search of the associations for this endpoint.
319  * We return the matching transport address too.
320  */
321 static struct sctp_association *__sctp_endpoint_lookup_assoc(
322 	const struct sctp_endpoint *ep,
323 	const union sctp_addr *paddr,
324 	struct sctp_transport **transport)
325 {
326 	struct sctp_association *asoc = NULL;
327 	struct sctp_association *tmp;
328 	struct sctp_transport *t = NULL;
329 	struct sctp_hashbucket *head;
330 	struct sctp_ep_common *epb;
331 	int hash;
332 	int rport;
333 
334 	*transport = NULL;
335 
336 	/* If the local port is not set, there can't be any associations
337 	 * on this endpoint.
338 	 */
339 	if (!ep->base.bind_addr.port)
340 		goto out;
341 
342 	rport = ntohs(paddr->v4.sin_port);
343 
344 	hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
345 				 rport);
346 	head = &sctp_assoc_hashtable[hash];
347 	read_lock(&head->lock);
348 	sctp_for_each_hentry(epb, &head->chain) {
349 		tmp = sctp_assoc(epb);
350 		if (tmp->ep != ep || rport != tmp->peer.port)
351 			continue;
352 
353 		t = sctp_assoc_lookup_paddr(tmp, paddr);
354 		if (t) {
355 			asoc = tmp;
356 			*transport = t;
357 			break;
358 		}
359 	}
360 	read_unlock(&head->lock);
361 out:
362 	return asoc;
363 }
364 
365 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
366 struct sctp_association *sctp_endpoint_lookup_assoc(
367 	const struct sctp_endpoint *ep,
368 	const union sctp_addr *paddr,
369 	struct sctp_transport **transport)
370 {
371 	struct sctp_association *asoc;
372 
373 	sctp_local_bh_disable();
374 	asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
375 	sctp_local_bh_enable();
376 
377 	return asoc;
378 }
379 
380 /* Look for any peeled off association from the endpoint that matches the
381  * given peer address.
382  */
383 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
384 				const union sctp_addr *paddr)
385 {
386 	struct sctp_sockaddr_entry *addr;
387 	struct sctp_bind_addr *bp;
388 	struct net *net = sock_net(ep->base.sk);
389 
390 	bp = &ep->base.bind_addr;
391 	/* This function is called with the socket lock held,
392 	 * so the address_list can not change.
393 	 */
394 	list_for_each_entry(addr, &bp->address_list, list) {
395 		if (sctp_has_association(net, &addr->a, paddr))
396 			return 1;
397 	}
398 
399 	return 0;
400 }
401 
402 /* Do delayed input processing.  This is scheduled by sctp_rcv().
403  * This may be called on BH or task time.
404  */
405 static void sctp_endpoint_bh_rcv(struct work_struct *work)
406 {
407 	struct sctp_endpoint *ep =
408 		container_of(work, struct sctp_endpoint,
409 			     base.inqueue.immediate);
410 	struct sctp_association *asoc;
411 	struct sock *sk;
412 	struct net *net;
413 	struct sctp_transport *transport;
414 	struct sctp_chunk *chunk;
415 	struct sctp_inq *inqueue;
416 	sctp_subtype_t subtype;
417 	sctp_state_t state;
418 	int error = 0;
419 	int first_time = 1;	/* is this the first time through the loop */
420 
421 	if (ep->base.dead)
422 		return;
423 
424 	asoc = NULL;
425 	inqueue = &ep->base.inqueue;
426 	sk = ep->base.sk;
427 	net = sock_net(sk);
428 
429 	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
430 		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
431 
432 		/* If the first chunk in the packet is AUTH, do special
433 		 * processing specified in Section 6.3 of SCTP-AUTH spec
434 		 */
435 		if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
436 			struct sctp_chunkhdr *next_hdr;
437 
438 			next_hdr = sctp_inq_peek(inqueue);
439 			if (!next_hdr)
440 				goto normal;
441 
442 			/* If the next chunk is COOKIE-ECHO, skip the AUTH
443 			 * chunk while saving a pointer to it so we can do
444 			 * Authentication later (during cookie-echo
445 			 * processing).
446 			 */
447 			if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
448 				chunk->auth_chunk = skb_clone(chunk->skb,
449 								GFP_ATOMIC);
450 				chunk->auth = 1;
451 				continue;
452 			}
453 		}
454 normal:
455 		/* We might have grown an association since last we
456 		 * looked, so try again.
457 		 *
458 		 * This happens when we've just processed our
459 		 * COOKIE-ECHO chunk.
460 		 */
461 		if (NULL == chunk->asoc) {
462 			asoc = sctp_endpoint_lookup_assoc(ep,
463 							  sctp_source(chunk),
464 							  &transport);
465 			chunk->asoc = asoc;
466 			chunk->transport = transport;
467 		}
468 
469 		state = asoc ? asoc->state : SCTP_STATE_CLOSED;
470 		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
471 			continue;
472 
473 		/* Remember where the last DATA chunk came from so we
474 		 * know where to send the SACK.
475 		 */
476 		if (asoc && sctp_chunk_is_data(chunk))
477 			asoc->peer.last_data_from = chunk->transport;
478 		else {
479 			SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
480 			if (asoc)
481 				asoc->stats.ictrlchunks++;
482 		}
483 
484 		if (chunk->transport)
485 			chunk->transport->last_time_heard = jiffies;
486 
487 		error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
488 				   ep, asoc, chunk, GFP_ATOMIC);
489 
490 		if (error && chunk)
491 			chunk->pdiscard = 1;
492 
493 		/* Check to see if the endpoint is freed in response to
494 		 * the incoming chunk. If so, get out of the while loop.
495 		 */
496 		if (!sctp_sk(sk)->ep)
497 			break;
498 
499 		if (first_time)
500 			first_time = 0;
501 	}
502 }
503