xref: /openbmc/linux/net/sctp/endpointola.c (revision de2bdb3d)
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, see
27  * <http://www.gnu.org/licenses/>.
28  *
29  * Please send any bug reports or fixes you make to the
30  * email address(es):
31  *    lksctp developers <linux-sctp@vger.kernel.org>
32  *
33  * Written or modified by:
34  *    La Monte H.P. Yarroll <piggy@acm.org>
35  *    Karl Knutson <karl@athena.chicago.il.us>
36  *    Jon Grimm <jgrimm@austin.ibm.com>
37  *    Daisy Chang <daisyc@us.ibm.com>
38  *    Dajiang Zhang <dajiang.zhang@nokia.com>
39  */
40 
41 #include <linux/types.h>
42 #include <linux/slab.h>
43 #include <linux/in.h>
44 #include <linux/random.h>	/* get_random_bytes() */
45 #include <net/sock.h>
46 #include <net/ipv6.h>
47 #include <net/sctp/sctp.h>
48 #include <net/sctp/sm.h>
49 
50 /* Forward declarations for internal helpers. */
51 static void sctp_endpoint_bh_rcv(struct work_struct *work);
52 
53 /*
54  * Initialize the base fields of the endpoint structure.
55  */
56 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
57 						struct sock *sk,
58 						gfp_t gfp)
59 {
60 	struct net *net = sock_net(sk);
61 	struct sctp_hmac_algo_param *auth_hmacs = NULL;
62 	struct sctp_chunks_param *auth_chunks = NULL;
63 	struct sctp_shared_key *null_key;
64 	int err;
65 
66 	ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
67 	if (!ep->digest)
68 		return NULL;
69 
70 	ep->auth_enable = net->sctp.auth_enable;
71 	if (ep->auth_enable) {
72 		/* Allocate space for HMACS and CHUNKS authentication
73 		 * variables.  There are arrays that we encode directly
74 		 * into parameters to make the rest of the operations easier.
75 		 */
76 		auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
77 				sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
78 		if (!auth_hmacs)
79 			goto nomem;
80 
81 		auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
82 					SCTP_NUM_CHUNK_TYPES, gfp);
83 		if (!auth_chunks)
84 			goto nomem;
85 
86 		/* Initialize the HMACS parameter.
87 		 * SCTP-AUTH: Section 3.3
88 		 *    Every endpoint supporting SCTP chunk authentication MUST
89 		 *    support the HMAC based on the SHA-1 algorithm.
90 		 */
91 		auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
92 		auth_hmacs->param_hdr.length =
93 					htons(sizeof(sctp_paramhdr_t) + 2);
94 		auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
95 
96 		/* Initialize the CHUNKS parameter */
97 		auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
98 		auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));
99 
100 		/* If the Add-IP functionality is enabled, we must
101 		 * authenticate, ASCONF and ASCONF-ACK chunks
102 		 */
103 		if (net->sctp.addip_enable) {
104 			auth_chunks->chunks[0] = SCTP_CID_ASCONF;
105 			auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
106 			auth_chunks->param_hdr.length =
107 					htons(sizeof(sctp_paramhdr_t) + 2);
108 		}
109 	}
110 
111 	/* Initialize the base structure. */
112 	/* What type of endpoint are we?  */
113 	ep->base.type = SCTP_EP_TYPE_SOCKET;
114 
115 	/* Initialize the basic object fields. */
116 	atomic_set(&ep->base.refcnt, 1);
117 	ep->base.dead = false;
118 
119 	/* Create an input queue.  */
120 	sctp_inq_init(&ep->base.inqueue);
121 
122 	/* Set its top-half handler */
123 	sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
124 
125 	/* Initialize the bind addr area */
126 	sctp_bind_addr_init(&ep->base.bind_addr, 0);
127 
128 	/* Remember who we are attached to.  */
129 	ep->base.sk = sk;
130 	sock_hold(ep->base.sk);
131 
132 	/* Create the lists of associations.  */
133 	INIT_LIST_HEAD(&ep->asocs);
134 
135 	/* Use SCTP specific send buffer space queues.  */
136 	ep->sndbuf_policy = net->sctp.sndbuf_policy;
137 
138 	sk->sk_data_ready = sctp_data_ready;
139 	sk->sk_write_space = sctp_write_space;
140 	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
141 
142 	/* Get the receive buffer policy for this endpoint */
143 	ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
144 
145 	/* Initialize the secret key used with cookie. */
146 	get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
147 
148 	/* SCTP-AUTH extensions*/
149 	INIT_LIST_HEAD(&ep->endpoint_shared_keys);
150 	null_key = sctp_auth_shkey_create(0, gfp);
151 	if (!null_key)
152 		goto nomem;
153 
154 	list_add(&null_key->key_list, &ep->endpoint_shared_keys);
155 
156 	/* Allocate and initialize transorms arrays for supported HMACs. */
157 	err = sctp_auth_init_hmacs(ep, gfp);
158 	if (err)
159 		goto nomem_hmacs;
160 
161 	/* Add the null key to the endpoint shared keys list and
162 	 * set the hmcas and chunks pointers.
163 	 */
164 	ep->auth_hmacs_list = auth_hmacs;
165 	ep->auth_chunk_list = auth_chunks;
166 	ep->prsctp_enable = net->sctp.prsctp_enable;
167 
168 	return ep;
169 
170 nomem_hmacs:
171 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
172 nomem:
173 	/* Free all allocations */
174 	kfree(auth_hmacs);
175 	kfree(auth_chunks);
176 	kfree(ep->digest);
177 	return NULL;
178 
179 }
180 
181 /* Create a sctp_endpoint with all that boring stuff initialized.
182  * Returns NULL if there isn't enough memory.
183  */
184 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
185 {
186 	struct sctp_endpoint *ep;
187 
188 	/* Build a local endpoint. */
189 	ep = kzalloc(sizeof(*ep), gfp);
190 	if (!ep)
191 		goto fail;
192 
193 	if (!sctp_endpoint_init(ep, sk, gfp))
194 		goto fail_init;
195 
196 	SCTP_DBG_OBJCNT_INC(ep);
197 	return ep;
198 
199 fail_init:
200 	kfree(ep);
201 fail:
202 	return NULL;
203 }
204 
205 /* Add an association to an endpoint.  */
206 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
207 			    struct sctp_association *asoc)
208 {
209 	struct sock *sk = ep->base.sk;
210 
211 	/* If this is a temporary association, don't bother
212 	 * since we'll be removing it shortly and don't
213 	 * want anyone to find it anyway.
214 	 */
215 	if (asoc->temp)
216 		return;
217 
218 	/* Now just add it to our list of asocs */
219 	list_add_tail(&asoc->asocs, &ep->asocs);
220 
221 	/* Increment the backlog value for a TCP-style listening socket. */
222 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
223 		sk->sk_ack_backlog++;
224 }
225 
226 /* Free the endpoint structure.  Delay cleanup until
227  * all users have released their reference count on this structure.
228  */
229 void sctp_endpoint_free(struct sctp_endpoint *ep)
230 {
231 	ep->base.dead = true;
232 
233 	ep->base.sk->sk_state = SCTP_SS_CLOSED;
234 
235 	/* Unlink this endpoint, so we can't find it again! */
236 	sctp_unhash_endpoint(ep);
237 
238 	sctp_endpoint_put(ep);
239 }
240 
241 /* Final destructor for endpoint.  */
242 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
243 {
244 	struct sock *sk;
245 
246 	if (unlikely(!ep->base.dead)) {
247 		WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
248 		return;
249 	}
250 
251 	/* Free the digest buffer */
252 	kfree(ep->digest);
253 
254 	/* SCTP-AUTH: Free up AUTH releated data such as shared keys
255 	 * chunks and hmacs arrays that were allocated
256 	 */
257 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
258 	kfree(ep->auth_hmacs_list);
259 	kfree(ep->auth_chunk_list);
260 
261 	/* AUTH - Free any allocated HMAC transform containers */
262 	sctp_auth_destroy_hmacs(ep->auth_hmacs);
263 
264 	/* Cleanup. */
265 	sctp_inq_free(&ep->base.inqueue);
266 	sctp_bind_addr_free(&ep->base.bind_addr);
267 
268 	memset(ep->secret_key, 0, sizeof(ep->secret_key));
269 
270 	/* Give up our hold on the sock. */
271 	sk = ep->base.sk;
272 	if (sk != NULL) {
273 		/* Remove and free the port */
274 		if (sctp_sk(sk)->bind_hash)
275 			sctp_put_port(sk);
276 
277 		sock_put(sk);
278 	}
279 
280 	kfree(ep);
281 	SCTP_DBG_OBJCNT_DEC(ep);
282 }
283 
284 /* Hold a reference to an endpoint. */
285 void sctp_endpoint_hold(struct sctp_endpoint *ep)
286 {
287 	atomic_inc(&ep->base.refcnt);
288 }
289 
290 /* Release a reference to an endpoint and clean up if there are
291  * no more references.
292  */
293 void sctp_endpoint_put(struct sctp_endpoint *ep)
294 {
295 	if (atomic_dec_and_test(&ep->base.refcnt))
296 		sctp_endpoint_destroy(ep);
297 }
298 
299 /* Is this the endpoint we are looking for?  */
300 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
301 					       struct net *net,
302 					       const union sctp_addr *laddr)
303 {
304 	struct sctp_endpoint *retval = NULL;
305 
306 	if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
307 	    net_eq(sock_net(ep->base.sk), net)) {
308 		if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
309 					 sctp_sk(ep->base.sk)))
310 			retval = ep;
311 	}
312 
313 	return retval;
314 }
315 
316 /* Find the association that goes with this chunk.
317  * We lookup the transport from hashtable at first, then get association
318  * through t->assoc.
319  */
320 struct sctp_association *sctp_endpoint_lookup_assoc(
321 	const struct sctp_endpoint *ep,
322 	const union sctp_addr *paddr,
323 	struct sctp_transport **transport)
324 {
325 	struct sctp_association *asoc = NULL;
326 	struct sctp_transport *t;
327 
328 	*transport = NULL;
329 
330 	/* If the local port is not set, there can't be any associations
331 	 * on this endpoint.
332 	 */
333 	if (!ep->base.bind_addr.port)
334 		goto out;
335 	t = sctp_epaddr_lookup_transport(ep, paddr);
336 	if (!t)
337 		goto out;
338 
339 	*transport = t;
340 	asoc = t->asoc;
341 out:
342 	return asoc;
343 }
344 
345 /* Look for any peeled off association from the endpoint that matches the
346  * given peer address.
347  */
348 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
349 				const union sctp_addr *paddr)
350 {
351 	struct sctp_sockaddr_entry *addr;
352 	struct sctp_bind_addr *bp;
353 	struct net *net = sock_net(ep->base.sk);
354 
355 	bp = &ep->base.bind_addr;
356 	/* This function is called with the socket lock held,
357 	 * so the address_list can not change.
358 	 */
359 	list_for_each_entry(addr, &bp->address_list, list) {
360 		if (sctp_has_association(net, &addr->a, paddr))
361 			return 1;
362 	}
363 
364 	return 0;
365 }
366 
367 /* Do delayed input processing.  This is scheduled by sctp_rcv().
368  * This may be called on BH or task time.
369  */
370 static void sctp_endpoint_bh_rcv(struct work_struct *work)
371 {
372 	struct sctp_endpoint *ep =
373 		container_of(work, struct sctp_endpoint,
374 			     base.inqueue.immediate);
375 	struct sctp_association *asoc;
376 	struct sock *sk;
377 	struct net *net;
378 	struct sctp_transport *transport;
379 	struct sctp_chunk *chunk;
380 	struct sctp_inq *inqueue;
381 	sctp_subtype_t subtype;
382 	sctp_state_t state;
383 	int error = 0;
384 	int first_time = 1;	/* is this the first time through the loop */
385 
386 	if (ep->base.dead)
387 		return;
388 
389 	asoc = NULL;
390 	inqueue = &ep->base.inqueue;
391 	sk = ep->base.sk;
392 	net = sock_net(sk);
393 
394 	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
395 		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
396 
397 		/* If the first chunk in the packet is AUTH, do special
398 		 * processing specified in Section 6.3 of SCTP-AUTH spec
399 		 */
400 		if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
401 			struct sctp_chunkhdr *next_hdr;
402 
403 			next_hdr = sctp_inq_peek(inqueue);
404 			if (!next_hdr)
405 				goto normal;
406 
407 			/* If the next chunk is COOKIE-ECHO, skip the AUTH
408 			 * chunk while saving a pointer to it so we can do
409 			 * Authentication later (during cookie-echo
410 			 * processing).
411 			 */
412 			if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
413 				chunk->auth_chunk = skb_clone(chunk->skb,
414 								GFP_ATOMIC);
415 				chunk->auth = 1;
416 				continue;
417 			}
418 		}
419 normal:
420 		/* We might have grown an association since last we
421 		 * looked, so try again.
422 		 *
423 		 * This happens when we've just processed our
424 		 * COOKIE-ECHO chunk.
425 		 */
426 		if (NULL == chunk->asoc) {
427 			asoc = sctp_endpoint_lookup_assoc(ep,
428 							  sctp_source(chunk),
429 							  &transport);
430 			chunk->asoc = asoc;
431 			chunk->transport = transport;
432 		}
433 
434 		state = asoc ? asoc->state : SCTP_STATE_CLOSED;
435 		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
436 			continue;
437 
438 		/* Remember where the last DATA chunk came from so we
439 		 * know where to send the SACK.
440 		 */
441 		if (asoc && sctp_chunk_is_data(chunk))
442 			asoc->peer.last_data_from = chunk->transport;
443 		else {
444 			SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
445 			if (asoc)
446 				asoc->stats.ictrlchunks++;
447 		}
448 
449 		if (chunk->transport)
450 			chunk->transport->last_time_heard = ktime_get();
451 
452 		error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
453 				   ep, asoc, chunk, GFP_ATOMIC);
454 
455 		if (error && chunk)
456 			chunk->pdiscard = 1;
457 
458 		/* Check to see if the endpoint is freed in response to
459 		 * the incoming chunk. If so, get out of the while loop.
460 		 */
461 		if (!sctp_sk(sk)->ep)
462 			break;
463 
464 		if (first_time)
465 			first_time = 0;
466 	}
467 }
468