1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001-2002 Intel Corp.
7  *
8  * This file is part of the SCTP kernel implementation
9  *
10  * These functions work with the state functions in sctp_sm_statefuns.c
11  * to implement the state operations.  These functions implement the
12  * steps which require modifying existing data structures.
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  *    C. Robin              <chris@hundredacre.ac.uk>
22  *    Jon Grimm             <jgrimm@us.ibm.com>
23  *    Xingang Guo           <xingang.guo@intel.com>
24  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
25  *    Sridhar Samudrala	    <sri@us.ibm.com>
26  *    Daisy Chang	    <daisyc@us.ibm.com>
27  *    Ardelle Fan	    <ardelle.fan@intel.com>
28  *    Kevin Gao             <kevin.gao@intel.com>
29  */
30 
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32 
33 #include <crypto/hash.h>
34 #include <linux/types.h>
35 #include <linux/kernel.h>
36 #include <linux/ip.h>
37 #include <linux/ipv6.h>
38 #include <linux/net.h>
39 #include <linux/inet.h>
40 #include <linux/scatterlist.h>
41 #include <linux/slab.h>
42 #include <net/sock.h>
43 
44 #include <linux/skbuff.h>
45 #include <linux/random.h>	/* for get_random_bytes */
46 #include <net/sctp/sctp.h>
47 #include <net/sctp/sm.h>
48 
49 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
50 					    __u8 type, __u8 flags, int paylen,
51 					    gfp_t gfp);
52 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
53 					 __u8 flags, int paylen, gfp_t gfp);
54 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
55 					   __u8 type, __u8 flags, int paylen,
56 					   gfp_t gfp);
57 static struct sctp_cookie_param *sctp_pack_cookie(
58 					const struct sctp_endpoint *ep,
59 					const struct sctp_association *asoc,
60 					const struct sctp_chunk *init_chunk,
61 					int *cookie_len,
62 					const __u8 *raw_addrs, int addrs_len);
63 static int sctp_process_param(struct sctp_association *asoc,
64 			      union sctp_params param,
65 			      const union sctp_addr *peer_addr,
66 			      gfp_t gfp);
67 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
68 			      const void *data);
69 
70 /* Control chunk destructor */
sctp_control_release_owner(struct sk_buff * skb)71 static void sctp_control_release_owner(struct sk_buff *skb)
72 {
73 	struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
74 
75 	if (chunk->shkey) {
76 		struct sctp_shared_key *shkey = chunk->shkey;
77 		struct sctp_association *asoc = chunk->asoc;
78 
79 		/* refcnt == 2 and !list_empty mean after this release, it's
80 		 * not being used anywhere, and it's time to notify userland
81 		 * that this shkey can be freed if it's been deactivated.
82 		 */
83 		if (shkey->deactivated && !list_empty(&shkey->key_list) &&
84 		    refcount_read(&shkey->refcnt) == 2) {
85 			struct sctp_ulpevent *ev;
86 
87 			ev = sctp_ulpevent_make_authkey(asoc, shkey->key_id,
88 							SCTP_AUTH_FREE_KEY,
89 							GFP_KERNEL);
90 			if (ev)
91 				asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
92 		}
93 		sctp_auth_shkey_release(chunk->shkey);
94 	}
95 }
96 
sctp_control_set_owner_w(struct sctp_chunk * chunk)97 static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
98 {
99 	struct sctp_association *asoc = chunk->asoc;
100 	struct sk_buff *skb = chunk->skb;
101 
102 	/* TODO: properly account for control chunks.
103 	 * To do it right we'll need:
104 	 *  1) endpoint if association isn't known.
105 	 *  2) proper memory accounting.
106 	 *
107 	 *  For now don't do anything for now.
108 	 */
109 	if (chunk->auth) {
110 		chunk->shkey = asoc->shkey;
111 		sctp_auth_shkey_hold(chunk->shkey);
112 	}
113 	skb->sk = asoc ? asoc->base.sk : NULL;
114 	skb_shinfo(skb)->destructor_arg = chunk;
115 	skb->destructor = sctp_control_release_owner;
116 }
117 
118 /* What was the inbound interface for this chunk? */
sctp_chunk_iif(const struct sctp_chunk * chunk)119 int sctp_chunk_iif(const struct sctp_chunk *chunk)
120 {
121 	struct sk_buff *skb = chunk->skb;
122 
123 	return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
124 }
125 
126 /* RFC 2960 3.3.2 Initiation (INIT) (1)
127  *
128  * Note 2: The ECN capable field is reserved for future use of
129  * Explicit Congestion Notification.
130  */
131 static const struct sctp_paramhdr ecap_param = {
132 	SCTP_PARAM_ECN_CAPABLE,
133 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
134 };
135 static const struct sctp_paramhdr prsctp_param = {
136 	SCTP_PARAM_FWD_TSN_SUPPORT,
137 	cpu_to_be16(sizeof(struct sctp_paramhdr)),
138 };
139 
140 /* A helper to initialize an op error inside a provided chunk, as most
141  * cause codes will be embedded inside an abort chunk.
142  */
sctp_init_cause(struct sctp_chunk * chunk,__be16 cause_code,size_t paylen)143 int sctp_init_cause(struct sctp_chunk *chunk, __be16 cause_code,
144 		    size_t paylen)
145 {
146 	struct sctp_errhdr err;
147 	__u16 len;
148 
149 	/* Cause code constants are now defined in network order.  */
150 	err.cause = cause_code;
151 	len = sizeof(err) + paylen;
152 	err.length = htons(len);
153 
154 	if (skb_tailroom(chunk->skb) < len)
155 		return -ENOSPC;
156 
157 	chunk->subh.err_hdr = sctp_addto_chunk(chunk, sizeof(err), &err);
158 
159 	return 0;
160 }
161 
162 /* 3.3.2 Initiation (INIT) (1)
163  *
164  * This chunk is used to initiate a SCTP association between two
165  * endpoints. The format of the INIT chunk is shown below:
166  *
167  *     0                   1                   2                   3
168  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
169  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
170  *    |   Type = 1    |  Chunk Flags  |      Chunk Length             |
171  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
172  *    |                         Initiate Tag                          |
173  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
174  *    |           Advertised Receiver Window Credit (a_rwnd)          |
175  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
176  *    |  Number of Outbound Streams   |  Number of Inbound Streams    |
177  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
178  *    |                          Initial TSN                          |
179  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
180  *    \                                                               \
181  *    /              Optional/Variable-Length Parameters              /
182  *    \                                                               \
183  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
184  *
185  *
186  * The INIT chunk contains the following parameters. Unless otherwise
187  * noted, each parameter MUST only be included once in the INIT chunk.
188  *
189  * Fixed Parameters                     Status
190  * ----------------------------------------------
191  * Initiate Tag                        Mandatory
192  * Advertised Receiver Window Credit   Mandatory
193  * Number of Outbound Streams          Mandatory
194  * Number of Inbound Streams           Mandatory
195  * Initial TSN                         Mandatory
196  *
197  * Variable Parameters                  Status     Type Value
198  * -------------------------------------------------------------
199  * IPv4 Address (Note 1)               Optional    5
200  * IPv6 Address (Note 1)               Optional    6
201  * Cookie Preservative                 Optional    9
202  * Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
203  * Host Name Address (Note 3)          Optional    11
204  * Supported Address Types (Note 4)    Optional    12
205  */
sctp_make_init(const struct sctp_association * asoc,const struct sctp_bind_addr * bp,gfp_t gfp,int vparam_len)206 struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
207 				  const struct sctp_bind_addr *bp,
208 				  gfp_t gfp, int vparam_len)
209 {
210 	struct sctp_supported_ext_param ext_param;
211 	struct sctp_adaptation_ind_param aiparam;
212 	struct sctp_paramhdr *auth_chunks = NULL;
213 	struct sctp_paramhdr *auth_hmacs = NULL;
214 	struct sctp_supported_addrs_param sat;
215 	struct sctp_endpoint *ep = asoc->ep;
216 	struct sctp_chunk *retval = NULL;
217 	int num_types, addrs_len = 0;
218 	struct sctp_inithdr init;
219 	union sctp_params addrs;
220 	struct sctp_sock *sp;
221 	__u8 extensions[5];
222 	size_t chunksize;
223 	__be16 types[2];
224 	int num_ext = 0;
225 
226 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
227 	 *
228 	 * Note 1: The INIT chunks can contain multiple addresses that
229 	 * can be IPv4 and/or IPv6 in any combination.
230 	 */
231 
232 	/* Convert the provided bind address list to raw format. */
233 	addrs = sctp_bind_addrs_to_raw(bp, &addrs_len, gfp);
234 
235 	init.init_tag		   = htonl(asoc->c.my_vtag);
236 	init.a_rwnd		   = htonl(asoc->rwnd);
237 	init.num_outbound_streams  = htons(asoc->c.sinit_num_ostreams);
238 	init.num_inbound_streams   = htons(asoc->c.sinit_max_instreams);
239 	init.initial_tsn	   = htonl(asoc->c.initial_tsn);
240 
241 	/* How many address types are needed? */
242 	sp = sctp_sk(asoc->base.sk);
243 	num_types = sp->pf->supported_addrs(sp, types);
244 
245 	chunksize = sizeof(init) + addrs_len;
246 	chunksize += SCTP_PAD4(SCTP_SAT_LEN(num_types));
247 
248 	if (asoc->ep->ecn_enable)
249 		chunksize += sizeof(ecap_param);
250 
251 	if (asoc->ep->prsctp_enable)
252 		chunksize += sizeof(prsctp_param);
253 
254 	/* ADDIP: Section 4.2.7:
255 	 *  An implementation supporting this extension [ADDIP] MUST list
256 	 *  the ASCONF,the ASCONF-ACK, and the AUTH  chunks in its INIT and
257 	 *  INIT-ACK parameters.
258 	 */
259 	if (asoc->ep->asconf_enable) {
260 		extensions[num_ext] = SCTP_CID_ASCONF;
261 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
262 		num_ext += 2;
263 	}
264 
265 	if (asoc->ep->reconf_enable) {
266 		extensions[num_ext] = SCTP_CID_RECONF;
267 		num_ext += 1;
268 	}
269 
270 	if (sp->adaptation_ind)
271 		chunksize += sizeof(aiparam);
272 
273 	if (asoc->ep->intl_enable) {
274 		extensions[num_ext] = SCTP_CID_I_DATA;
275 		num_ext += 1;
276 	}
277 
278 	chunksize += vparam_len;
279 
280 	/* Account for AUTH related parameters */
281 	if (ep->auth_enable) {
282 		/* Add random parameter length*/
283 		chunksize += sizeof(asoc->c.auth_random);
284 
285 		/* Add HMACS parameter length if any were defined */
286 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
287 		if (auth_hmacs->length)
288 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
289 		else
290 			auth_hmacs = NULL;
291 
292 		/* Add CHUNKS parameter length */
293 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
294 		if (auth_chunks->length)
295 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
296 		else
297 			auth_chunks = NULL;
298 
299 		extensions[num_ext] = SCTP_CID_AUTH;
300 		num_ext += 1;
301 	}
302 
303 	/* If we have any extensions to report, account for that */
304 	if (num_ext)
305 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
306 
307 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
308 	 *
309 	 * Note 3: An INIT chunk MUST NOT contain more than one Host
310 	 * Name address parameter. Moreover, the sender of the INIT
311 	 * MUST NOT combine any other address types with the Host Name
312 	 * address in the INIT. The receiver of INIT MUST ignore any
313 	 * other address types if the Host Name address parameter is
314 	 * present in the received INIT chunk.
315 	 *
316 	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
317 	 */
318 
319 	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
320 	if (!retval)
321 		goto nodata;
322 
323 	retval->subh.init_hdr =
324 		sctp_addto_chunk(retval, sizeof(init), &init);
325 	retval->param_hdr.v =
326 		sctp_addto_chunk(retval, addrs_len, addrs.v);
327 
328 	/* RFC 2960 3.3.2 Initiation (INIT) (1)
329 	 *
330 	 * Note 4: This parameter, when present, specifies all the
331 	 * address types the sending endpoint can support. The absence
332 	 * of this parameter indicates that the sending endpoint can
333 	 * support any address type.
334 	 */
335 	sat.param_hdr.type = SCTP_PARAM_SUPPORTED_ADDRESS_TYPES;
336 	sat.param_hdr.length = htons(SCTP_SAT_LEN(num_types));
337 	sctp_addto_chunk(retval, sizeof(sat), &sat);
338 	sctp_addto_chunk(retval, num_types * sizeof(__u16), &types);
339 
340 	if (asoc->ep->ecn_enable)
341 		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
342 
343 	/* Add the supported extensions parameter.  Be nice and add this
344 	 * fist before addiding the parameters for the extensions themselves
345 	 */
346 	if (num_ext) {
347 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
348 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
349 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
350 		sctp_addto_param(retval, num_ext, extensions);
351 	}
352 
353 	if (asoc->ep->prsctp_enable)
354 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
355 
356 	if (sp->adaptation_ind) {
357 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
358 		aiparam.param_hdr.length = htons(sizeof(aiparam));
359 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
360 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
361 	}
362 
363 	/* Add SCTP-AUTH chunks to the parameter list */
364 	if (ep->auth_enable) {
365 		sctp_addto_chunk(retval, sizeof(asoc->c.auth_random),
366 				 asoc->c.auth_random);
367 		if (auth_hmacs)
368 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
369 					auth_hmacs);
370 		if (auth_chunks)
371 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
372 					auth_chunks);
373 	}
374 nodata:
375 	kfree(addrs.v);
376 	return retval;
377 }
378 
sctp_make_init_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk,gfp_t gfp,int unkparam_len)379 struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
380 				      const struct sctp_chunk *chunk,
381 				      gfp_t gfp, int unkparam_len)
382 {
383 	struct sctp_supported_ext_param ext_param;
384 	struct sctp_adaptation_ind_param aiparam;
385 	struct sctp_paramhdr *auth_chunks = NULL;
386 	struct sctp_paramhdr *auth_random = NULL;
387 	struct sctp_paramhdr *auth_hmacs = NULL;
388 	struct sctp_chunk *retval = NULL;
389 	struct sctp_cookie_param *cookie;
390 	struct sctp_inithdr initack;
391 	union sctp_params addrs;
392 	struct sctp_sock *sp;
393 	__u8 extensions[5];
394 	size_t chunksize;
395 	int num_ext = 0;
396 	int cookie_len;
397 	int addrs_len;
398 
399 	/* Note: there may be no addresses to embed. */
400 	addrs = sctp_bind_addrs_to_raw(&asoc->base.bind_addr, &addrs_len, gfp);
401 
402 	initack.init_tag	        = htonl(asoc->c.my_vtag);
403 	initack.a_rwnd			= htonl(asoc->rwnd);
404 	initack.num_outbound_streams	= htons(asoc->c.sinit_num_ostreams);
405 	initack.num_inbound_streams	= htons(asoc->c.sinit_max_instreams);
406 	initack.initial_tsn		= htonl(asoc->c.initial_tsn);
407 
408 	/* FIXME:  We really ought to build the cookie right
409 	 * into the packet instead of allocating more fresh memory.
410 	 */
411 	cookie = sctp_pack_cookie(asoc->ep, asoc, chunk, &cookie_len,
412 				  addrs.v, addrs_len);
413 	if (!cookie)
414 		goto nomem_cookie;
415 
416 	/* Calculate the total size of allocation, include the reserved
417 	 * space for reporting unknown parameters if it is specified.
418 	 */
419 	sp = sctp_sk(asoc->base.sk);
420 	chunksize = sizeof(initack) + addrs_len + cookie_len + unkparam_len;
421 
422 	/* Tell peer that we'll do ECN only if peer advertised such cap.  */
423 	if (asoc->peer.ecn_capable)
424 		chunksize += sizeof(ecap_param);
425 
426 	if (asoc->peer.prsctp_capable)
427 		chunksize += sizeof(prsctp_param);
428 
429 	if (asoc->peer.asconf_capable) {
430 		extensions[num_ext] = SCTP_CID_ASCONF;
431 		extensions[num_ext+1] = SCTP_CID_ASCONF_ACK;
432 		num_ext += 2;
433 	}
434 
435 	if (asoc->peer.reconf_capable) {
436 		extensions[num_ext] = SCTP_CID_RECONF;
437 		num_ext += 1;
438 	}
439 
440 	if (sp->adaptation_ind)
441 		chunksize += sizeof(aiparam);
442 
443 	if (asoc->peer.intl_capable) {
444 		extensions[num_ext] = SCTP_CID_I_DATA;
445 		num_ext += 1;
446 	}
447 
448 	if (asoc->peer.auth_capable) {
449 		auth_random = (struct sctp_paramhdr *)asoc->c.auth_random;
450 		chunksize += ntohs(auth_random->length);
451 
452 		auth_hmacs = (struct sctp_paramhdr *)asoc->c.auth_hmacs;
453 		if (auth_hmacs->length)
454 			chunksize += SCTP_PAD4(ntohs(auth_hmacs->length));
455 		else
456 			auth_hmacs = NULL;
457 
458 		auth_chunks = (struct sctp_paramhdr *)asoc->c.auth_chunks;
459 		if (auth_chunks->length)
460 			chunksize += SCTP_PAD4(ntohs(auth_chunks->length));
461 		else
462 			auth_chunks = NULL;
463 
464 		extensions[num_ext] = SCTP_CID_AUTH;
465 		num_ext += 1;
466 	}
467 
468 	if (num_ext)
469 		chunksize += SCTP_PAD4(sizeof(ext_param) + num_ext);
470 
471 	/* Now allocate and fill out the chunk.  */
472 	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
473 	if (!retval)
474 		goto nomem_chunk;
475 
476 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
477 	 *
478 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
479 	 * HEARTBEAT ACK, * etc.) to the same destination transport
480 	 * address from which it received the DATA or control chunk
481 	 * to which it is replying.
482 	 *
483 	 * [INIT ACK back to where the INIT came from.]
484 	 */
485 	if (chunk->transport)
486 		retval->transport =
487 			sctp_assoc_lookup_paddr(asoc,
488 						&chunk->transport->ipaddr);
489 
490 	retval->subh.init_hdr =
491 		sctp_addto_chunk(retval, sizeof(initack), &initack);
492 	retval->param_hdr.v = sctp_addto_chunk(retval, addrs_len, addrs.v);
493 	sctp_addto_chunk(retval, cookie_len, cookie);
494 	if (asoc->peer.ecn_capable)
495 		sctp_addto_chunk(retval, sizeof(ecap_param), &ecap_param);
496 	if (num_ext) {
497 		ext_param.param_hdr.type = SCTP_PARAM_SUPPORTED_EXT;
498 		ext_param.param_hdr.length = htons(sizeof(ext_param) + num_ext);
499 		sctp_addto_chunk(retval, sizeof(ext_param), &ext_param);
500 		sctp_addto_param(retval, num_ext, extensions);
501 	}
502 	if (asoc->peer.prsctp_capable)
503 		sctp_addto_chunk(retval, sizeof(prsctp_param), &prsctp_param);
504 
505 	if (sp->adaptation_ind) {
506 		aiparam.param_hdr.type = SCTP_PARAM_ADAPTATION_LAYER_IND;
507 		aiparam.param_hdr.length = htons(sizeof(aiparam));
508 		aiparam.adaptation_ind = htonl(sp->adaptation_ind);
509 		sctp_addto_chunk(retval, sizeof(aiparam), &aiparam);
510 	}
511 
512 	if (asoc->peer.auth_capable) {
513 		sctp_addto_chunk(retval, ntohs(auth_random->length),
514 				 auth_random);
515 		if (auth_hmacs)
516 			sctp_addto_chunk(retval, ntohs(auth_hmacs->length),
517 					auth_hmacs);
518 		if (auth_chunks)
519 			sctp_addto_chunk(retval, ntohs(auth_chunks->length),
520 					auth_chunks);
521 	}
522 
523 	/* We need to remove the const qualifier at this point.  */
524 	retval->asoc = (struct sctp_association *) asoc;
525 
526 nomem_chunk:
527 	kfree(cookie);
528 nomem_cookie:
529 	kfree(addrs.v);
530 	return retval;
531 }
532 
533 /* 3.3.11 Cookie Echo (COOKIE ECHO) (10):
534  *
535  * This chunk is used only during the initialization of an association.
536  * It is sent by the initiator of an association to its peer to complete
537  * the initialization process. This chunk MUST precede any DATA chunk
538  * sent within the association, but MAY be bundled with one or more DATA
539  * chunks in the same packet.
540  *
541  *      0                   1                   2                   3
542  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
543  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
544  *     |   Type = 10   |Chunk  Flags   |         Length                |
545  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
546  *     /                     Cookie                                    /
547  *     \                                                               \
548  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
549  *
550  * Chunk Flags: 8 bit
551  *
552  *   Set to zero on transmit and ignored on receipt.
553  *
554  * Length: 16 bits (unsigned integer)
555  *
556  *   Set to the size of the chunk in bytes, including the 4 bytes of
557  *   the chunk header and the size of the Cookie.
558  *
559  * Cookie: variable size
560  *
561  *   This field must contain the exact cookie received in the
562  *   State Cookie parameter from the previous INIT ACK.
563  *
564  *   An implementation SHOULD make the cookie as small as possible
565  *   to insure interoperability.
566  */
sctp_make_cookie_echo(const struct sctp_association * asoc,const struct sctp_chunk * chunk)567 struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
568 					 const struct sctp_chunk *chunk)
569 {
570 	struct sctp_chunk *retval;
571 	int cookie_len;
572 	void *cookie;
573 
574 	cookie = asoc->peer.cookie;
575 	cookie_len = asoc->peer.cookie_len;
576 
577 	/* Build a cookie echo chunk.  */
578 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
579 				   cookie_len, GFP_ATOMIC);
580 	if (!retval)
581 		goto nodata;
582 	retval->subh.cookie_hdr =
583 		sctp_addto_chunk(retval, cookie_len, cookie);
584 
585 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
586 	 *
587 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
588 	 * HEARTBEAT ACK, * etc.) to the same destination transport
589 	 * address from which it * received the DATA or control chunk
590 	 * to which it is replying.
591 	 *
592 	 * [COOKIE ECHO back to where the INIT ACK came from.]
593 	 */
594 	if (chunk)
595 		retval->transport = chunk->transport;
596 
597 nodata:
598 	return retval;
599 }
600 
601 /* 3.3.12 Cookie Acknowledgement (COOKIE ACK) (11):
602  *
603  * This chunk is used only during the initialization of an
604  * association.  It is used to acknowledge the receipt of a COOKIE
605  * ECHO chunk.  This chunk MUST precede any DATA or SACK chunk sent
606  * within the association, but MAY be bundled with one or more DATA
607  * chunks or SACK chunk in the same SCTP packet.
608  *
609  *      0                   1                   2                   3
610  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
611  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
612  *     |   Type = 11   |Chunk  Flags   |     Length = 4                |
613  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
614  *
615  * Chunk Flags: 8 bits
616  *
617  *   Set to zero on transmit and ignored on receipt.
618  */
sctp_make_cookie_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk)619 struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
620 					const struct sctp_chunk *chunk)
621 {
622 	struct sctp_chunk *retval;
623 
624 	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
625 
626 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
627 	 *
628 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
629 	 * HEARTBEAT ACK, * etc.) to the same destination transport
630 	 * address from which it * received the DATA or control chunk
631 	 * to which it is replying.
632 	 *
633 	 * [COOKIE ACK back to where the COOKIE ECHO came from.]
634 	 */
635 	if (retval && chunk && chunk->transport)
636 		retval->transport =
637 			sctp_assoc_lookup_paddr(asoc,
638 						&chunk->transport->ipaddr);
639 
640 	return retval;
641 }
642 
643 /*
644  *  Appendix A: Explicit Congestion Notification:
645  *  CWR:
646  *
647  *  RFC 2481 details a specific bit for a sender to send in the header of
648  *  its next outbound TCP segment to indicate to its peer that it has
649  *  reduced its congestion window.  This is termed the CWR bit.  For
650  *  SCTP the same indication is made by including the CWR chunk.
651  *  This chunk contains one data element, i.e. the TSN number that
652  *  was sent in the ECNE chunk.  This element represents the lowest
653  *  TSN number in the datagram that was originally marked with the
654  *  CE bit.
655  *
656  *     0                   1                   2                   3
657  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
658  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
659  *    | Chunk Type=13 | Flags=00000000|    Chunk Length = 8           |
660  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
661  *    |                      Lowest TSN Number                        |
662  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
663  *
664  *     Note: The CWR is considered a Control chunk.
665  */
sctp_make_cwr(const struct sctp_association * asoc,const __u32 lowest_tsn,const struct sctp_chunk * chunk)666 struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
667 				 const __u32 lowest_tsn,
668 				 const struct sctp_chunk *chunk)
669 {
670 	struct sctp_chunk *retval;
671 	struct sctp_cwrhdr cwr;
672 
673 	cwr.lowest_tsn = htonl(lowest_tsn);
674 	retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
675 				   sizeof(cwr), GFP_ATOMIC);
676 
677 	if (!retval)
678 		goto nodata;
679 
680 	retval->subh.ecn_cwr_hdr =
681 		sctp_addto_chunk(retval, sizeof(cwr), &cwr);
682 
683 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
684 	 *
685 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
686 	 * HEARTBEAT ACK, * etc.) to the same destination transport
687 	 * address from which it * received the DATA or control chunk
688 	 * to which it is replying.
689 	 *
690 	 * [Report a reduced congestion window back to where the ECNE
691 	 * came from.]
692 	 */
693 	if (chunk)
694 		retval->transport = chunk->transport;
695 
696 nodata:
697 	return retval;
698 }
699 
700 /* Make an ECNE chunk.  This is a congestion experienced report.  */
sctp_make_ecne(const struct sctp_association * asoc,const __u32 lowest_tsn)701 struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
702 				  const __u32 lowest_tsn)
703 {
704 	struct sctp_chunk *retval;
705 	struct sctp_ecnehdr ecne;
706 
707 	ecne.lowest_tsn = htonl(lowest_tsn);
708 	retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
709 				   sizeof(ecne), GFP_ATOMIC);
710 	if (!retval)
711 		goto nodata;
712 	retval->subh.ecne_hdr =
713 		sctp_addto_chunk(retval, sizeof(ecne), &ecne);
714 
715 nodata:
716 	return retval;
717 }
718 
719 /* Make a DATA chunk for the given association from the provided
720  * parameters.  However, do not populate the data payload.
721  */
sctp_make_datafrag_empty(const struct sctp_association * asoc,const struct sctp_sndrcvinfo * sinfo,int len,__u8 flags,gfp_t gfp)722 struct sctp_chunk *sctp_make_datafrag_empty(const struct sctp_association *asoc,
723 					    const struct sctp_sndrcvinfo *sinfo,
724 					    int len, __u8 flags, gfp_t gfp)
725 {
726 	struct sctp_chunk *retval;
727 	struct sctp_datahdr dp;
728 
729 	/* We assign the TSN as LATE as possible, not here when
730 	 * creating the chunk.
731 	 */
732 	memset(&dp, 0, sizeof(dp));
733 	dp.ppid = sinfo->sinfo_ppid;
734 	dp.stream = htons(sinfo->sinfo_stream);
735 
736 	/* Set the flags for an unordered send.  */
737 	if (sinfo->sinfo_flags & SCTP_UNORDERED)
738 		flags |= SCTP_DATA_UNORDERED;
739 
740 	retval = sctp_make_data(asoc, flags, sizeof(dp) + len, gfp);
741 	if (!retval)
742 		return NULL;
743 
744 	retval->subh.data_hdr = sctp_addto_chunk(retval, sizeof(dp), &dp);
745 	memcpy(&retval->sinfo, sinfo, sizeof(struct sctp_sndrcvinfo));
746 
747 	return retval;
748 }
749 
750 /* Create a selective ackowledgement (SACK) for the given
751  * association.  This reports on which TSN's we've seen to date,
752  * including duplicates and gaps.
753  */
sctp_make_sack(struct sctp_association * asoc)754 struct sctp_chunk *sctp_make_sack(struct sctp_association *asoc)
755 {
756 	struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
757 	struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
758 	__u16 num_gabs, num_dup_tsns;
759 	struct sctp_transport *trans;
760 	struct sctp_chunk *retval;
761 	struct sctp_sackhdr sack;
762 	__u32 ctsn;
763 	int len;
764 
765 	memset(gabs, 0, sizeof(gabs));
766 	ctsn = sctp_tsnmap_get_ctsn(map);
767 
768 	pr_debug("%s: sackCTSNAck sent:0x%x\n", __func__, ctsn);
769 
770 	/* How much room is needed in the chunk? */
771 	num_gabs = sctp_tsnmap_num_gabs(map, gabs);
772 	num_dup_tsns = sctp_tsnmap_num_dups(map);
773 
774 	/* Initialize the SACK header.  */
775 	sack.cum_tsn_ack	    = htonl(ctsn);
776 	sack.a_rwnd 		    = htonl(asoc->a_rwnd);
777 	sack.num_gap_ack_blocks     = htons(num_gabs);
778 	sack.num_dup_tsns           = htons(num_dup_tsns);
779 
780 	len = sizeof(sack)
781 		+ sizeof(struct sctp_gap_ack_block) * num_gabs
782 		+ sizeof(__u32) * num_dup_tsns;
783 
784 	/* Create the chunk.  */
785 	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
786 	if (!retval)
787 		goto nodata;
788 
789 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
790 	 *
791 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
792 	 * HEARTBEAT ACK, etc.) to the same destination transport
793 	 * address from which it received the DATA or control chunk to
794 	 * which it is replying.  This rule should also be followed if
795 	 * the endpoint is bundling DATA chunks together with the
796 	 * reply chunk.
797 	 *
798 	 * However, when acknowledging multiple DATA chunks received
799 	 * in packets from different source addresses in a single
800 	 * SACK, the SACK chunk may be transmitted to one of the
801 	 * destination transport addresses from which the DATA or
802 	 * control chunks being acknowledged were received.
803 	 *
804 	 * [BUG:  We do not implement the following paragraph.
805 	 * Perhaps we should remember the last transport we used for a
806 	 * SACK and avoid that (if possible) if we have seen any
807 	 * duplicates. --piggy]
808 	 *
809 	 * When a receiver of a duplicate DATA chunk sends a SACK to a
810 	 * multi- homed endpoint it MAY be beneficial to vary the
811 	 * destination address and not use the source address of the
812 	 * DATA chunk.  The reason being that receiving a duplicate
813 	 * from a multi-homed endpoint might indicate that the return
814 	 * path (as specified in the source address of the DATA chunk)
815 	 * for the SACK is broken.
816 	 *
817 	 * [Send to the address from which we last received a DATA chunk.]
818 	 */
819 	retval->transport = asoc->peer.last_data_from;
820 
821 	retval->subh.sack_hdr =
822 		sctp_addto_chunk(retval, sizeof(sack), &sack);
823 
824 	/* Add the gap ack block information.   */
825 	if (num_gabs)
826 		sctp_addto_chunk(retval, sizeof(__u32) * num_gabs,
827 				 gabs);
828 
829 	/* Add the duplicate TSN information.  */
830 	if (num_dup_tsns) {
831 		asoc->stats.idupchunks += num_dup_tsns;
832 		sctp_addto_chunk(retval, sizeof(__u32) * num_dup_tsns,
833 				 sctp_tsnmap_get_dups(map));
834 	}
835 	/* Once we have a sack generated, check to see what our sack
836 	 * generation is, if its 0, reset the transports to 0, and reset
837 	 * the association generation to 1
838 	 *
839 	 * The idea is that zero is never used as a valid generation for the
840 	 * association so no transport will match after a wrap event like this,
841 	 * Until the next sack
842 	 */
843 	if (++asoc->peer.sack_generation == 0) {
844 		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
845 				    transports)
846 			trans->sack_generation = 0;
847 		asoc->peer.sack_generation = 1;
848 	}
849 nodata:
850 	return retval;
851 }
852 
853 /* Make a SHUTDOWN chunk. */
sctp_make_shutdown(const struct sctp_association * asoc,const struct sctp_chunk * chunk)854 struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
855 				      const struct sctp_chunk *chunk)
856 {
857 	struct sctp_shutdownhdr shut;
858 	struct sctp_chunk *retval;
859 	__u32 ctsn;
860 
861 	ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
862 	shut.cum_tsn_ack = htonl(ctsn);
863 
864 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
865 				   sizeof(shut), GFP_ATOMIC);
866 	if (!retval)
867 		goto nodata;
868 
869 	retval->subh.shutdown_hdr =
870 		sctp_addto_chunk(retval, sizeof(shut), &shut);
871 
872 	if (chunk)
873 		retval->transport = chunk->transport;
874 nodata:
875 	return retval;
876 }
877 
sctp_make_shutdown_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk)878 struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
879 					  const struct sctp_chunk *chunk)
880 {
881 	struct sctp_chunk *retval;
882 
883 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
884 				   GFP_ATOMIC);
885 
886 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
887 	 *
888 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
889 	 * HEARTBEAT ACK, * etc.) to the same destination transport
890 	 * address from which it * received the DATA or control chunk
891 	 * to which it is replying.
892 	 *
893 	 * [ACK back to where the SHUTDOWN came from.]
894 	 */
895 	if (retval && chunk)
896 		retval->transport = chunk->transport;
897 
898 	return retval;
899 }
900 
sctp_make_shutdown_complete(const struct sctp_association * asoc,const struct sctp_chunk * chunk)901 struct sctp_chunk *sctp_make_shutdown_complete(
902 					const struct sctp_association *asoc,
903 					const struct sctp_chunk *chunk)
904 {
905 	struct sctp_chunk *retval;
906 	__u8 flags = 0;
907 
908 	/* Set the T-bit if we have no association (vtag will be
909 	 * reflected)
910 	 */
911 	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
912 
913 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
914 				   0, GFP_ATOMIC);
915 
916 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
917 	 *
918 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
919 	 * HEARTBEAT ACK, * etc.) to the same destination transport
920 	 * address from which it * received the DATA or control chunk
921 	 * to which it is replying.
922 	 *
923 	 * [Report SHUTDOWN COMPLETE back to where the SHUTDOWN ACK
924 	 * came from.]
925 	 */
926 	if (retval && chunk)
927 		retval->transport = chunk->transport;
928 
929 	return retval;
930 }
931 
932 /* Create an ABORT.  Note that we set the T bit if we have no
933  * association, except when responding to an INIT (sctpimpguide 2.41).
934  */
sctp_make_abort(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const size_t hint)935 struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
936 				   const struct sctp_chunk *chunk,
937 				   const size_t hint)
938 {
939 	struct sctp_chunk *retval;
940 	__u8 flags = 0;
941 
942 	/* Set the T-bit if we have no association and 'chunk' is not
943 	 * an INIT (vtag will be reflected).
944 	 */
945 	if (!asoc) {
946 		if (chunk && chunk->chunk_hdr &&
947 		    chunk->chunk_hdr->type == SCTP_CID_INIT)
948 			flags = 0;
949 		else
950 			flags = SCTP_CHUNK_FLAG_T;
951 	}
952 
953 	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
954 				   GFP_ATOMIC);
955 
956 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
957 	 *
958 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
959 	 * HEARTBEAT ACK, * etc.) to the same destination transport
960 	 * address from which it * received the DATA or control chunk
961 	 * to which it is replying.
962 	 *
963 	 * [ABORT back to where the offender came from.]
964 	 */
965 	if (retval && chunk)
966 		retval->transport = chunk->transport;
967 
968 	return retval;
969 }
970 
971 /* Helper to create ABORT with a NO_USER_DATA error.  */
sctp_make_abort_no_data(const struct sctp_association * asoc,const struct sctp_chunk * chunk,__u32 tsn)972 struct sctp_chunk *sctp_make_abort_no_data(
973 					const struct sctp_association *asoc,
974 					const struct sctp_chunk *chunk,
975 					__u32 tsn)
976 {
977 	struct sctp_chunk *retval;
978 	__be32 payload;
979 
980 	retval = sctp_make_abort(asoc, chunk,
981 				 sizeof(struct sctp_errhdr) + sizeof(tsn));
982 
983 	if (!retval)
984 		goto no_mem;
985 
986 	/* Put the tsn back into network byte order.  */
987 	payload = htonl(tsn);
988 	sctp_init_cause(retval, SCTP_ERROR_NO_DATA, sizeof(payload));
989 	sctp_addto_chunk(retval, sizeof(payload), (const void *)&payload);
990 
991 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
992 	 *
993 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
994 	 * HEARTBEAT ACK, * etc.) to the same destination transport
995 	 * address from which it * received the DATA or control chunk
996 	 * to which it is replying.
997 	 *
998 	 * [ABORT back to where the offender came from.]
999 	 */
1000 	if (chunk)
1001 		retval->transport = chunk->transport;
1002 
1003 no_mem:
1004 	return retval;
1005 }
1006 
1007 /* Helper to create ABORT with a SCTP_ERROR_USER_ABORT error.  */
sctp_make_abort_user(const struct sctp_association * asoc,struct msghdr * msg,size_t paylen)1008 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *asoc,
1009 					struct msghdr *msg,
1010 					size_t paylen)
1011 {
1012 	struct sctp_chunk *retval;
1013 	void *payload = NULL;
1014 	int err;
1015 
1016 	retval = sctp_make_abort(asoc, NULL,
1017 				 sizeof(struct sctp_errhdr) + paylen);
1018 	if (!retval)
1019 		goto err_chunk;
1020 
1021 	if (paylen) {
1022 		/* Put the msg_iov together into payload.  */
1023 		payload = kmalloc(paylen, GFP_KERNEL);
1024 		if (!payload)
1025 			goto err_payload;
1026 
1027 		err = memcpy_from_msg(payload, msg, paylen);
1028 		if (err < 0)
1029 			goto err_copy;
1030 	}
1031 
1032 	sctp_init_cause(retval, SCTP_ERROR_USER_ABORT, paylen);
1033 	sctp_addto_chunk(retval, paylen, payload);
1034 
1035 	if (paylen)
1036 		kfree(payload);
1037 
1038 	return retval;
1039 
1040 err_copy:
1041 	kfree(payload);
1042 err_payload:
1043 	sctp_chunk_free(retval);
1044 	retval = NULL;
1045 err_chunk:
1046 	return retval;
1047 }
1048 
1049 /* Append bytes to the end of a parameter.  Will panic if chunk is not big
1050  * enough.
1051  */
sctp_addto_param(struct sctp_chunk * chunk,int len,const void * data)1052 static void *sctp_addto_param(struct sctp_chunk *chunk, int len,
1053 			      const void *data)
1054 {
1055 	int chunklen = ntohs(chunk->chunk_hdr->length);
1056 	void *target;
1057 
1058 	target = skb_put(chunk->skb, len);
1059 
1060 	if (data)
1061 		memcpy(target, data, len);
1062 	else
1063 		memset(target, 0, len);
1064 
1065 	/* Adjust the chunk length field.  */
1066 	chunk->chunk_hdr->length = htons(chunklen + len);
1067 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1068 
1069 	return target;
1070 }
1071 
1072 /* Make an ABORT chunk with a PROTOCOL VIOLATION cause code. */
sctp_make_abort_violation(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const __u8 * payload,const size_t paylen)1073 struct sctp_chunk *sctp_make_abort_violation(
1074 					const struct sctp_association *asoc,
1075 					const struct sctp_chunk *chunk,
1076 					const __u8 *payload,
1077 					const size_t paylen)
1078 {
1079 	struct sctp_chunk  *retval;
1080 	struct sctp_paramhdr phdr;
1081 
1082 	retval = sctp_make_abort(asoc, chunk, sizeof(struct sctp_errhdr) +
1083 					      paylen + sizeof(phdr));
1084 	if (!retval)
1085 		goto end;
1086 
1087 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, paylen +
1088 							    sizeof(phdr));
1089 
1090 	phdr.type = htons(chunk->chunk_hdr->type);
1091 	phdr.length = chunk->chunk_hdr->length;
1092 	sctp_addto_chunk(retval, paylen, payload);
1093 	sctp_addto_param(retval, sizeof(phdr), &phdr);
1094 
1095 end:
1096 	return retval;
1097 }
1098 
sctp_make_violation_paramlen(const struct sctp_association * asoc,const struct sctp_chunk * chunk,struct sctp_paramhdr * param)1099 struct sctp_chunk *sctp_make_violation_paramlen(
1100 					const struct sctp_association *asoc,
1101 					const struct sctp_chunk *chunk,
1102 					struct sctp_paramhdr *param)
1103 {
1104 	static const char error[] = "The following parameter had invalid length:";
1105 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr) +
1106 			     sizeof(*param);
1107 	struct sctp_chunk *retval;
1108 
1109 	retval = sctp_make_abort(asoc, chunk, payload_len);
1110 	if (!retval)
1111 		goto nodata;
1112 
1113 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
1114 			sizeof(error) + sizeof(*param));
1115 	sctp_addto_chunk(retval, sizeof(error), error);
1116 	sctp_addto_param(retval, sizeof(*param), param);
1117 
1118 nodata:
1119 	return retval;
1120 }
1121 
sctp_make_violation_max_retrans(const struct sctp_association * asoc,const struct sctp_chunk * chunk)1122 struct sctp_chunk *sctp_make_violation_max_retrans(
1123 					const struct sctp_association *asoc,
1124 					const struct sctp_chunk *chunk)
1125 {
1126 	static const char error[] = "Association exceeded its max_retrans count";
1127 	size_t payload_len = sizeof(error) + sizeof(struct sctp_errhdr);
1128 	struct sctp_chunk *retval;
1129 
1130 	retval = sctp_make_abort(asoc, chunk, payload_len);
1131 	if (!retval)
1132 		goto nodata;
1133 
1134 	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION, sizeof(error));
1135 	sctp_addto_chunk(retval, sizeof(error), error);
1136 
1137 nodata:
1138 	return retval;
1139 }
1140 
sctp_make_new_encap_port(const struct sctp_association * asoc,const struct sctp_chunk * chunk)1141 struct sctp_chunk *sctp_make_new_encap_port(const struct sctp_association *asoc,
1142 					    const struct sctp_chunk *chunk)
1143 {
1144 	struct sctp_new_encap_port_hdr nep;
1145 	struct sctp_chunk *retval;
1146 
1147 	retval = sctp_make_abort(asoc, chunk,
1148 				 sizeof(struct sctp_errhdr) + sizeof(nep));
1149 	if (!retval)
1150 		goto nodata;
1151 
1152 	sctp_init_cause(retval, SCTP_ERROR_NEW_ENCAP_PORT, sizeof(nep));
1153 	nep.cur_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
1154 	nep.new_port = chunk->transport->encap_port;
1155 	sctp_addto_chunk(retval, sizeof(nep), &nep);
1156 
1157 nodata:
1158 	return retval;
1159 }
1160 
1161 /* Make a HEARTBEAT chunk.  */
sctp_make_heartbeat(const struct sctp_association * asoc,const struct sctp_transport * transport,__u32 probe_size)1162 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
1163 				       const struct sctp_transport *transport,
1164 				       __u32 probe_size)
1165 {
1166 	struct sctp_sender_hb_info hbinfo = {};
1167 	struct sctp_chunk *retval;
1168 
1169 	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
1170 				   sizeof(hbinfo), GFP_ATOMIC);
1171 
1172 	if (!retval)
1173 		goto nodata;
1174 
1175 	hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO;
1176 	hbinfo.param_hdr.length = htons(sizeof(hbinfo));
1177 	hbinfo.daddr = transport->ipaddr;
1178 	hbinfo.sent_at = jiffies;
1179 	hbinfo.hb_nonce = transport->hb_nonce;
1180 	hbinfo.probe_size = probe_size;
1181 
1182 	/* Cast away the 'const', as this is just telling the chunk
1183 	 * what transport it belongs to.
1184 	 */
1185 	retval->transport = (struct sctp_transport *) transport;
1186 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, sizeof(hbinfo),
1187 						&hbinfo);
1188 	retval->pmtu_probe = !!probe_size;
1189 
1190 nodata:
1191 	return retval;
1192 }
1193 
sctp_make_heartbeat_ack(const struct sctp_association * asoc,const struct sctp_chunk * chunk,const void * payload,const size_t paylen)1194 struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
1195 					   const struct sctp_chunk *chunk,
1196 					   const void *payload,
1197 					   const size_t paylen)
1198 {
1199 	struct sctp_chunk *retval;
1200 
1201 	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
1202 				    GFP_ATOMIC);
1203 	if (!retval)
1204 		goto nodata;
1205 
1206 	retval->subh.hbs_hdr = sctp_addto_chunk(retval, paylen, payload);
1207 
1208 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1209 	 *
1210 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1211 	 * HEARTBEAT ACK, * etc.) to the same destination transport
1212 	 * address from which it * received the DATA or control chunk
1213 	 * to which it is replying.
1214 	 *
1215 	 * [HBACK back to where the HEARTBEAT came from.]
1216 	 */
1217 	if (chunk)
1218 		retval->transport = chunk->transport;
1219 
1220 nodata:
1221 	return retval;
1222 }
1223 
1224 /* RFC4820 3. Padding Chunk (PAD)
1225  *  0                   1                   2                   3
1226  *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
1227  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1228  * | Type = 0x84   |   Flags=0     |             Length            |
1229  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1230  * |                                                               |
1231  * \                         Padding Data                          /
1232  * /                                                               \
1233  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1234  */
sctp_make_pad(const struct sctp_association * asoc,int len)1235 struct sctp_chunk *sctp_make_pad(const struct sctp_association *asoc, int len)
1236 {
1237 	struct sctp_chunk *retval;
1238 
1239 	retval = sctp_make_control(asoc, SCTP_CID_PAD, 0, len, GFP_ATOMIC);
1240 	if (!retval)
1241 		return NULL;
1242 
1243 	skb_put_zero(retval->skb, len);
1244 	retval->chunk_hdr->length = htons(ntohs(retval->chunk_hdr->length) + len);
1245 	retval->chunk_end = skb_tail_pointer(retval->skb);
1246 
1247 	return retval;
1248 }
1249 
1250 /* Create an Operation Error chunk with the specified space reserved.
1251  * This routine can be used for containing multiple causes in the chunk.
1252  */
sctp_make_op_error_space(const struct sctp_association * asoc,const struct sctp_chunk * chunk,size_t size)1253 static struct sctp_chunk *sctp_make_op_error_space(
1254 					const struct sctp_association *asoc,
1255 					const struct sctp_chunk *chunk,
1256 					size_t size)
1257 {
1258 	struct sctp_chunk *retval;
1259 
1260 	retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
1261 				   sizeof(struct sctp_errhdr) + size,
1262 				   GFP_ATOMIC);
1263 	if (!retval)
1264 		goto nodata;
1265 
1266 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
1267 	 *
1268 	 * An endpoint SHOULD transmit reply chunks (e.g., SACK,
1269 	 * HEARTBEAT ACK, etc.) to the same destination transport
1270 	 * address from which it received the DATA or control chunk
1271 	 * to which it is replying.
1272 	 *
1273 	 */
1274 	if (chunk)
1275 		retval->transport = chunk->transport;
1276 
1277 nodata:
1278 	return retval;
1279 }
1280 
1281 /* Create an Operation Error chunk of a fixed size, specifically,
1282  * min(asoc->pathmtu, SCTP_DEFAULT_MAXSEGMENT) - overheads.
1283  * This is a helper function to allocate an error chunk for those
1284  * invalid parameter codes in which we may not want to report all the
1285  * errors, if the incoming chunk is large. If it can't fit in a single
1286  * packet, we ignore it.
1287  */
sctp_make_op_error_limited(const struct sctp_association * asoc,const struct sctp_chunk * chunk)1288 static inline struct sctp_chunk *sctp_make_op_error_limited(
1289 					const struct sctp_association *asoc,
1290 					const struct sctp_chunk *chunk)
1291 {
1292 	size_t size = SCTP_DEFAULT_MAXSEGMENT;
1293 	struct sctp_sock *sp = NULL;
1294 
1295 	if (asoc) {
1296 		size = min_t(size_t, size, asoc->pathmtu);
1297 		sp = sctp_sk(asoc->base.sk);
1298 	}
1299 
1300 	size = sctp_mtu_payload(sp, size, sizeof(struct sctp_errhdr));
1301 
1302 	return sctp_make_op_error_space(asoc, chunk, size);
1303 }
1304 
1305 /* Create an Operation Error chunk.  */
sctp_make_op_error(const struct sctp_association * asoc,const struct sctp_chunk * chunk,__be16 cause_code,const void * payload,size_t paylen,size_t reserve_tail)1306 struct sctp_chunk *sctp_make_op_error(const struct sctp_association *asoc,
1307 				      const struct sctp_chunk *chunk,
1308 				      __be16 cause_code, const void *payload,
1309 				      size_t paylen, size_t reserve_tail)
1310 {
1311 	struct sctp_chunk *retval;
1312 
1313 	retval = sctp_make_op_error_space(asoc, chunk, paylen + reserve_tail);
1314 	if (!retval)
1315 		goto nodata;
1316 
1317 	sctp_init_cause(retval, cause_code, paylen + reserve_tail);
1318 	sctp_addto_chunk(retval, paylen, payload);
1319 	if (reserve_tail)
1320 		sctp_addto_param(retval, reserve_tail, NULL);
1321 
1322 nodata:
1323 	return retval;
1324 }
1325 
sctp_make_auth(const struct sctp_association * asoc,__u16 key_id)1326 struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc,
1327 				  __u16 key_id)
1328 {
1329 	struct sctp_authhdr auth_hdr;
1330 	struct sctp_hmac *hmac_desc;
1331 	struct sctp_chunk *retval;
1332 
1333 	/* Get the first hmac that the peer told us to use */
1334 	hmac_desc = sctp_auth_asoc_get_hmac(asoc);
1335 	if (unlikely(!hmac_desc))
1336 		return NULL;
1337 
1338 	retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
1339 				   hmac_desc->hmac_len + sizeof(auth_hdr),
1340 				   GFP_ATOMIC);
1341 	if (!retval)
1342 		return NULL;
1343 
1344 	auth_hdr.hmac_id = htons(hmac_desc->hmac_id);
1345 	auth_hdr.shkey_id = htons(key_id);
1346 
1347 	retval->subh.auth_hdr = sctp_addto_chunk(retval, sizeof(auth_hdr),
1348 						 &auth_hdr);
1349 
1350 	skb_put_zero(retval->skb, hmac_desc->hmac_len);
1351 
1352 	/* Adjust the chunk header to include the empty MAC */
1353 	retval->chunk_hdr->length =
1354 		htons(ntohs(retval->chunk_hdr->length) + hmac_desc->hmac_len);
1355 	retval->chunk_end = skb_tail_pointer(retval->skb);
1356 
1357 	return retval;
1358 }
1359 
1360 
1361 /********************************************************************
1362  * 2nd Level Abstractions
1363  ********************************************************************/
1364 
1365 /* Turn an skb into a chunk.
1366  * FIXME: Eventually move the structure directly inside the skb->cb[].
1367  *
1368  * sctpimpguide-05.txt Section 2.8.2
1369  * M1) Each time a new DATA chunk is transmitted
1370  * set the 'TSN.Missing.Report' count for that TSN to 0. The
1371  * 'TSN.Missing.Report' count will be used to determine missing chunks
1372  * and when to fast retransmit.
1373  *
1374  */
sctp_chunkify(struct sk_buff * skb,const struct sctp_association * asoc,struct sock * sk,gfp_t gfp)1375 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
1376 				 const struct sctp_association *asoc,
1377 				 struct sock *sk, gfp_t gfp)
1378 {
1379 	struct sctp_chunk *retval;
1380 
1381 	retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
1382 
1383 	if (!retval)
1384 		goto nodata;
1385 	if (!sk)
1386 		pr_debug("%s: chunkifying skb:%p w/o an sk\n", __func__, skb);
1387 
1388 	INIT_LIST_HEAD(&retval->list);
1389 	retval->skb		= skb;
1390 	retval->asoc		= (struct sctp_association *)asoc;
1391 	retval->singleton	= 1;
1392 
1393 	retval->fast_retransmit = SCTP_CAN_FRTX;
1394 
1395 	/* Polish the bead hole.  */
1396 	INIT_LIST_HEAD(&retval->transmitted_list);
1397 	INIT_LIST_HEAD(&retval->frag_list);
1398 	SCTP_DBG_OBJCNT_INC(chunk);
1399 	refcount_set(&retval->refcnt, 1);
1400 
1401 nodata:
1402 	return retval;
1403 }
1404 
1405 /* Set chunk->source and dest based on the IP header in chunk->skb.  */
sctp_init_addrs(struct sctp_chunk * chunk,union sctp_addr * src,union sctp_addr * dest)1406 void sctp_init_addrs(struct sctp_chunk *chunk, union sctp_addr *src,
1407 		     union sctp_addr *dest)
1408 {
1409 	memcpy(&chunk->source, src, sizeof(union sctp_addr));
1410 	memcpy(&chunk->dest, dest, sizeof(union sctp_addr));
1411 }
1412 
1413 /* Extract the source address from a chunk.  */
sctp_source(const struct sctp_chunk * chunk)1414 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
1415 {
1416 	/* If we have a known transport, use that.  */
1417 	if (chunk->transport) {
1418 		return &chunk->transport->ipaddr;
1419 	} else {
1420 		/* Otherwise, extract it from the IP header.  */
1421 		return &chunk->source;
1422 	}
1423 }
1424 
1425 /* Create a new chunk, setting the type and flags headers from the
1426  * arguments, reserving enough space for a 'paylen' byte payload.
1427  */
_sctp_make_chunk(const struct sctp_association * asoc,__u8 type,__u8 flags,int paylen,gfp_t gfp)1428 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
1429 					   __u8 type, __u8 flags, int paylen,
1430 					   gfp_t gfp)
1431 {
1432 	struct sctp_chunkhdr *chunk_hdr;
1433 	struct sctp_chunk *retval;
1434 	struct sk_buff *skb;
1435 	struct sock *sk;
1436 	int chunklen;
1437 
1438 	chunklen = SCTP_PAD4(sizeof(*chunk_hdr) + paylen);
1439 	if (chunklen > SCTP_MAX_CHUNK_LEN)
1440 		goto nodata;
1441 
1442 	/* No need to allocate LL here, as this is only a chunk. */
1443 	skb = alloc_skb(chunklen, gfp);
1444 	if (!skb)
1445 		goto nodata;
1446 
1447 	/* Make room for the chunk header.  */
1448 	chunk_hdr = (struct sctp_chunkhdr *)skb_put(skb, sizeof(*chunk_hdr));
1449 	chunk_hdr->type	  = type;
1450 	chunk_hdr->flags  = flags;
1451 	chunk_hdr->length = htons(sizeof(*chunk_hdr));
1452 
1453 	sk = asoc ? asoc->base.sk : NULL;
1454 	retval = sctp_chunkify(skb, asoc, sk, gfp);
1455 	if (!retval) {
1456 		kfree_skb(skb);
1457 		goto nodata;
1458 	}
1459 
1460 	retval->chunk_hdr = chunk_hdr;
1461 	retval->chunk_end = ((__u8 *)chunk_hdr) + sizeof(*chunk_hdr);
1462 
1463 	/* Determine if the chunk needs to be authenticated */
1464 	if (sctp_auth_send_cid(type, asoc))
1465 		retval->auth = 1;
1466 
1467 	return retval;
1468 nodata:
1469 	return NULL;
1470 }
1471 
sctp_make_data(const struct sctp_association * asoc,__u8 flags,int paylen,gfp_t gfp)1472 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
1473 					 __u8 flags, int paylen, gfp_t gfp)
1474 {
1475 	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
1476 }
1477 
sctp_make_idata(const struct sctp_association * asoc,__u8 flags,int paylen,gfp_t gfp)1478 struct sctp_chunk *sctp_make_idata(const struct sctp_association *asoc,
1479 				   __u8 flags, int paylen, gfp_t gfp)
1480 {
1481 	return _sctp_make_chunk(asoc, SCTP_CID_I_DATA, flags, paylen, gfp);
1482 }
1483 
sctp_make_control(const struct sctp_association * asoc,__u8 type,__u8 flags,int paylen,gfp_t gfp)1484 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
1485 					    __u8 type, __u8 flags, int paylen,
1486 					    gfp_t gfp)
1487 {
1488 	struct sctp_chunk *chunk;
1489 
1490 	chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
1491 	if (chunk)
1492 		sctp_control_set_owner_w(chunk);
1493 
1494 	return chunk;
1495 }
1496 
1497 /* Release the memory occupied by a chunk.  */
sctp_chunk_destroy(struct sctp_chunk * chunk)1498 static void sctp_chunk_destroy(struct sctp_chunk *chunk)
1499 {
1500 	BUG_ON(!list_empty(&chunk->list));
1501 	list_del_init(&chunk->transmitted_list);
1502 
1503 	consume_skb(chunk->skb);
1504 	consume_skb(chunk->auth_chunk);
1505 
1506 	SCTP_DBG_OBJCNT_DEC(chunk);
1507 	kmem_cache_free(sctp_chunk_cachep, chunk);
1508 }
1509 
1510 /* Possibly, free the chunk.  */
sctp_chunk_free(struct sctp_chunk * chunk)1511 void sctp_chunk_free(struct sctp_chunk *chunk)
1512 {
1513 	/* Release our reference on the message tracker. */
1514 	if (chunk->msg)
1515 		sctp_datamsg_put(chunk->msg);
1516 
1517 	sctp_chunk_put(chunk);
1518 }
1519 
1520 /* Grab a reference to the chunk. */
sctp_chunk_hold(struct sctp_chunk * ch)1521 void sctp_chunk_hold(struct sctp_chunk *ch)
1522 {
1523 	refcount_inc(&ch->refcnt);
1524 }
1525 
1526 /* Release a reference to the chunk. */
sctp_chunk_put(struct sctp_chunk * ch)1527 void sctp_chunk_put(struct sctp_chunk *ch)
1528 {
1529 	if (refcount_dec_and_test(&ch->refcnt))
1530 		sctp_chunk_destroy(ch);
1531 }
1532 
1533 /* Append bytes to the end of a chunk.  Will panic if chunk is not big
1534  * enough.
1535  */
sctp_addto_chunk(struct sctp_chunk * chunk,int len,const void * data)1536 void *sctp_addto_chunk(struct sctp_chunk *chunk, int len, const void *data)
1537 {
1538 	int chunklen = ntohs(chunk->chunk_hdr->length);
1539 	int padlen = SCTP_PAD4(chunklen) - chunklen;
1540 	void *target;
1541 
1542 	skb_put_zero(chunk->skb, padlen);
1543 	target = skb_put_data(chunk->skb, data, len);
1544 
1545 	/* Adjust the chunk length field.  */
1546 	chunk->chunk_hdr->length = htons(chunklen + padlen + len);
1547 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1548 
1549 	return target;
1550 }
1551 
1552 /* Append bytes from user space to the end of a chunk.  Will panic if
1553  * chunk is not big enough.
1554  * Returns a kernel err value.
1555  */
sctp_user_addto_chunk(struct sctp_chunk * chunk,int len,struct iov_iter * from)1556 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
1557 			  struct iov_iter *from)
1558 {
1559 	void *target;
1560 
1561 	/* Make room in chunk for data.  */
1562 	target = skb_put(chunk->skb, len);
1563 
1564 	/* Copy data (whole iovec) into chunk */
1565 	if (!copy_from_iter_full(target, len, from))
1566 		return -EFAULT;
1567 
1568 	/* Adjust the chunk length field.  */
1569 	chunk->chunk_hdr->length =
1570 		htons(ntohs(chunk->chunk_hdr->length) + len);
1571 	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1572 
1573 	return 0;
1574 }
1575 
1576 /* Helper function to assign a TSN if needed.  This assumes that both
1577  * the data_hdr and association have already been assigned.
1578  */
sctp_chunk_assign_ssn(struct sctp_chunk * chunk)1579 void sctp_chunk_assign_ssn(struct sctp_chunk *chunk)
1580 {
1581 	struct sctp_stream *stream;
1582 	struct sctp_chunk *lchunk;
1583 	struct sctp_datamsg *msg;
1584 	__u16 ssn, sid;
1585 
1586 	if (chunk->has_ssn)
1587 		return;
1588 
1589 	/* All fragments will be on the same stream */
1590 	sid = ntohs(chunk->subh.data_hdr->stream);
1591 	stream = &chunk->asoc->stream;
1592 
1593 	/* Now assign the sequence number to the entire message.
1594 	 * All fragments must have the same stream sequence number.
1595 	 */
1596 	msg = chunk->msg;
1597 	list_for_each_entry(lchunk, &msg->chunks, frag_list) {
1598 		if (lchunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
1599 			ssn = 0;
1600 		} else {
1601 			if (lchunk->chunk_hdr->flags & SCTP_DATA_LAST_FRAG)
1602 				ssn = sctp_ssn_next(stream, out, sid);
1603 			else
1604 				ssn = sctp_ssn_peek(stream, out, sid);
1605 		}
1606 
1607 		lchunk->subh.data_hdr->ssn = htons(ssn);
1608 		lchunk->has_ssn = 1;
1609 	}
1610 }
1611 
1612 /* Helper function to assign a TSN if needed.  This assumes that both
1613  * the data_hdr and association have already been assigned.
1614  */
sctp_chunk_assign_tsn(struct sctp_chunk * chunk)1615 void sctp_chunk_assign_tsn(struct sctp_chunk *chunk)
1616 {
1617 	if (!chunk->has_tsn) {
1618 		/* This is the last possible instant to
1619 		 * assign a TSN.
1620 		 */
1621 		chunk->subh.data_hdr->tsn =
1622 			htonl(sctp_association_get_next_tsn(chunk->asoc));
1623 		chunk->has_tsn = 1;
1624 	}
1625 }
1626 
1627 /* Create a CLOSED association to use with an incoming packet.  */
sctp_make_temp_asoc(const struct sctp_endpoint * ep,struct sctp_chunk * chunk,gfp_t gfp)1628 struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
1629 					     struct sctp_chunk *chunk,
1630 					     gfp_t gfp)
1631 {
1632 	struct sctp_association *asoc;
1633 	enum sctp_scope scope;
1634 	struct sk_buff *skb;
1635 
1636 	/* Create the bare association.  */
1637 	scope = sctp_scope(sctp_source(chunk));
1638 	asoc = sctp_association_new(ep, ep->base.sk, scope, gfp);
1639 	if (!asoc)
1640 		goto nodata;
1641 	asoc->temp = 1;
1642 	skb = chunk->skb;
1643 	/* Create an entry for the source address of the packet.  */
1644 	SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
1645 
1646 nodata:
1647 	return asoc;
1648 }
1649 
1650 /* Build a cookie representing asoc.
1651  * This INCLUDES the param header needed to put the cookie in the INIT ACK.
1652  */
sctp_pack_cookie(const struct sctp_endpoint * ep,const struct sctp_association * asoc,const struct sctp_chunk * init_chunk,int * cookie_len,const __u8 * raw_addrs,int addrs_len)1653 static struct sctp_cookie_param *sctp_pack_cookie(
1654 					const struct sctp_endpoint *ep,
1655 					const struct sctp_association *asoc,
1656 					const struct sctp_chunk *init_chunk,
1657 					int *cookie_len, const __u8 *raw_addrs,
1658 					int addrs_len)
1659 {
1660 	struct sctp_signed_cookie *cookie;
1661 	struct sctp_cookie_param *retval;
1662 	int headersize, bodysize;
1663 
1664 	/* Header size is static data prior to the actual cookie, including
1665 	 * any padding.
1666 	 */
1667 	headersize = sizeof(struct sctp_paramhdr) +
1668 		     (sizeof(struct sctp_signed_cookie) -
1669 		      sizeof(struct sctp_cookie));
1670 	bodysize = sizeof(struct sctp_cookie)
1671 		+ ntohs(init_chunk->chunk_hdr->length) + addrs_len;
1672 
1673 	/* Pad out the cookie to a multiple to make the signature
1674 	 * functions simpler to write.
1675 	 */
1676 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1677 		bodysize += SCTP_COOKIE_MULTIPLE
1678 			- (bodysize % SCTP_COOKIE_MULTIPLE);
1679 	*cookie_len = headersize + bodysize;
1680 
1681 	/* Clear this memory since we are sending this data structure
1682 	 * out on the network.
1683 	 */
1684 	retval = kzalloc(*cookie_len, GFP_ATOMIC);
1685 	if (!retval)
1686 		goto nodata;
1687 
1688 	cookie = (struct sctp_signed_cookie *) retval->body;
1689 
1690 	/* Set up the parameter header.  */
1691 	retval->p.type = SCTP_PARAM_STATE_COOKIE;
1692 	retval->p.length = htons(*cookie_len);
1693 
1694 	/* Copy the cookie part of the association itself.  */
1695 	cookie->c = asoc->c;
1696 	/* Save the raw address list length in the cookie. */
1697 	cookie->c.raw_addr_list_len = addrs_len;
1698 
1699 	/* Remember PR-SCTP capability. */
1700 	cookie->c.prsctp_capable = asoc->peer.prsctp_capable;
1701 
1702 	/* Save adaptation indication in the cookie. */
1703 	cookie->c.adaptation_ind = asoc->peer.adaptation_ind;
1704 
1705 	/* Set an expiration time for the cookie.  */
1706 	cookie->c.expiration = ktime_add(asoc->cookie_life,
1707 					 ktime_get_real());
1708 
1709 	/* Copy the peer's init packet.  */
1710 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
1711 	       ntohs(init_chunk->chunk_hdr->length));
1712 
1713 	/* Copy the raw local address list of the association. */
1714 	memcpy((__u8 *)&cookie->c.peer_init[0] +
1715 	       ntohs(init_chunk->chunk_hdr->length), raw_addrs, addrs_len);
1716 
1717 	if (sctp_sk(ep->base.sk)->hmac) {
1718 		struct crypto_shash *tfm = sctp_sk(ep->base.sk)->hmac;
1719 		int err;
1720 
1721 		/* Sign the message.  */
1722 		err = crypto_shash_setkey(tfm, ep->secret_key,
1723 					  sizeof(ep->secret_key)) ?:
1724 		      crypto_shash_tfm_digest(tfm, (u8 *)&cookie->c, bodysize,
1725 					      cookie->signature);
1726 		if (err)
1727 			goto free_cookie;
1728 	}
1729 
1730 	return retval;
1731 
1732 free_cookie:
1733 	kfree(retval);
1734 nodata:
1735 	*cookie_len = 0;
1736 	return NULL;
1737 }
1738 
1739 /* Unpack the cookie from COOKIE ECHO chunk, recreating the association.  */
sctp_unpack_cookie(const struct sctp_endpoint * ep,const struct sctp_association * asoc,struct sctp_chunk * chunk,gfp_t gfp,int * error,struct sctp_chunk ** errp)1740 struct sctp_association *sctp_unpack_cookie(
1741 					const struct sctp_endpoint *ep,
1742 					const struct sctp_association *asoc,
1743 					struct sctp_chunk *chunk, gfp_t gfp,
1744 					int *error, struct sctp_chunk **errp)
1745 {
1746 	struct sctp_association *retval = NULL;
1747 	int headersize, bodysize, fixed_size;
1748 	struct sctp_signed_cookie *cookie;
1749 	struct sk_buff *skb = chunk->skb;
1750 	struct sctp_cookie *bear_cookie;
1751 	__u8 *digest = ep->digest;
1752 	enum sctp_scope scope;
1753 	unsigned int len;
1754 	ktime_t kt;
1755 
1756 	/* Header size is static data prior to the actual cookie, including
1757 	 * any padding.
1758 	 */
1759 	headersize = sizeof(struct sctp_chunkhdr) +
1760 		     (sizeof(struct sctp_signed_cookie) -
1761 		      sizeof(struct sctp_cookie));
1762 	bodysize = ntohs(chunk->chunk_hdr->length) - headersize;
1763 	fixed_size = headersize + sizeof(struct sctp_cookie);
1764 
1765 	/* Verify that the chunk looks like it even has a cookie.
1766 	 * There must be enough room for our cookie and our peer's
1767 	 * INIT chunk.
1768 	 */
1769 	len = ntohs(chunk->chunk_hdr->length);
1770 	if (len < fixed_size + sizeof(struct sctp_chunkhdr))
1771 		goto malformed;
1772 
1773 	/* Verify that the cookie has been padded out. */
1774 	if (bodysize % SCTP_COOKIE_MULTIPLE)
1775 		goto malformed;
1776 
1777 	/* Process the cookie.  */
1778 	cookie = chunk->subh.cookie_hdr;
1779 	bear_cookie = &cookie->c;
1780 
1781 	if (!sctp_sk(ep->base.sk)->hmac)
1782 		goto no_hmac;
1783 
1784 	/* Check the signature.  */
1785 	{
1786 		struct crypto_shash *tfm = sctp_sk(ep->base.sk)->hmac;
1787 		int err;
1788 
1789 		err = crypto_shash_setkey(tfm, ep->secret_key,
1790 					  sizeof(ep->secret_key)) ?:
1791 		      crypto_shash_tfm_digest(tfm, (u8 *)bear_cookie, bodysize,
1792 					      digest);
1793 		if (err) {
1794 			*error = -SCTP_IERROR_NOMEM;
1795 			goto fail;
1796 		}
1797 	}
1798 
1799 	if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) {
1800 		*error = -SCTP_IERROR_BAD_SIG;
1801 		goto fail;
1802 	}
1803 
1804 no_hmac:
1805 	/* IG Section 2.35.2:
1806 	 *  3) Compare the port numbers and the verification tag contained
1807 	 *     within the COOKIE ECHO chunk to the actual port numbers and the
1808 	 *     verification tag within the SCTP common header of the received
1809 	 *     packet. If these values do not match the packet MUST be silently
1810 	 *     discarded,
1811 	 */
1812 	if (ntohl(chunk->sctp_hdr->vtag) != bear_cookie->my_vtag) {
1813 		*error = -SCTP_IERROR_BAD_TAG;
1814 		goto fail;
1815 	}
1816 
1817 	if (chunk->sctp_hdr->source != bear_cookie->peer_addr.v4.sin_port ||
1818 	    ntohs(chunk->sctp_hdr->dest) != bear_cookie->my_port) {
1819 		*error = -SCTP_IERROR_BAD_PORTS;
1820 		goto fail;
1821 	}
1822 
1823 	/* Check to see if the cookie is stale.  If there is already
1824 	 * an association, there is no need to check cookie's expiration
1825 	 * for init collision case of lost COOKIE ACK.
1826 	 * If skb has been timestamped, then use the stamp, otherwise
1827 	 * use current time.  This introduces a small possibility that
1828 	 * a cookie may be considered expired, but this would only slow
1829 	 * down the new association establishment instead of every packet.
1830 	 */
1831 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
1832 		kt = skb_get_ktime(skb);
1833 	else
1834 		kt = ktime_get_real();
1835 
1836 	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
1837 		suseconds_t usecs = ktime_to_us(ktime_sub(kt, bear_cookie->expiration));
1838 		__be32 n = htonl(usecs);
1839 
1840 		/*
1841 		 * Section 3.3.10.3 Stale Cookie Error (3)
1842 		 *
1843 		 * Cause of error
1844 		 * ---------------
1845 		 * Stale Cookie Error:  Indicates the receipt of a valid State
1846 		 * Cookie that has expired.
1847 		 */
1848 		*errp = sctp_make_op_error(asoc, chunk,
1849 					   SCTP_ERROR_STALE_COOKIE, &n,
1850 					   sizeof(n), 0);
1851 		if (*errp)
1852 			*error = -SCTP_IERROR_STALE_COOKIE;
1853 		else
1854 			*error = -SCTP_IERROR_NOMEM;
1855 
1856 		goto fail;
1857 	}
1858 
1859 	/* Make a new base association.  */
1860 	scope = sctp_scope(sctp_source(chunk));
1861 	retval = sctp_association_new(ep, ep->base.sk, scope, gfp);
1862 	if (!retval) {
1863 		*error = -SCTP_IERROR_NOMEM;
1864 		goto fail;
1865 	}
1866 
1867 	/* Set up our peer's port number.  */
1868 	retval->peer.port = ntohs(chunk->sctp_hdr->source);
1869 
1870 	/* Populate the association from the cookie.  */
1871 	memcpy(&retval->c, bear_cookie, sizeof(*bear_cookie));
1872 
1873 	if (sctp_assoc_set_bind_addr_from_cookie(retval, bear_cookie,
1874 						 GFP_ATOMIC) < 0) {
1875 		*error = -SCTP_IERROR_NOMEM;
1876 		goto fail;
1877 	}
1878 
1879 	/* Also, add the destination address. */
1880 	if (list_empty(&retval->base.bind_addr.address_list)) {
1881 		sctp_add_bind_addr(&retval->base.bind_addr, &chunk->dest,
1882 				   sizeof(chunk->dest), SCTP_ADDR_SRC,
1883 				   GFP_ATOMIC);
1884 	}
1885 
1886 	retval->next_tsn = retval->c.initial_tsn;
1887 	retval->ctsn_ack_point = retval->next_tsn - 1;
1888 	retval->addip_serial = retval->c.initial_tsn;
1889 	retval->strreset_outseq = retval->c.initial_tsn;
1890 	retval->adv_peer_ack_point = retval->ctsn_ack_point;
1891 	retval->peer.prsctp_capable = retval->c.prsctp_capable;
1892 	retval->peer.adaptation_ind = retval->c.adaptation_ind;
1893 
1894 	/* The INIT stuff will be done by the side effects.  */
1895 	return retval;
1896 
1897 fail:
1898 	if (retval)
1899 		sctp_association_free(retval);
1900 
1901 	return NULL;
1902 
1903 malformed:
1904 	/* Yikes!  The packet is either corrupt or deliberately
1905 	 * malformed.
1906 	 */
1907 	*error = -SCTP_IERROR_MALFORMED;
1908 	goto fail;
1909 }
1910 
1911 /********************************************************************
1912  * 3rd Level Abstractions
1913  ********************************************************************/
1914 
1915 struct __sctp_missing {
1916 	__be32 num_missing;
1917 	__be16 type;
1918 }  __packed;
1919 
1920 /*
1921  * Report a missing mandatory parameter.
1922  */
sctp_process_missing_param(const struct sctp_association * asoc,enum sctp_param paramtype,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1923 static int sctp_process_missing_param(const struct sctp_association *asoc,
1924 				      enum sctp_param paramtype,
1925 				      struct sctp_chunk *chunk,
1926 				      struct sctp_chunk **errp)
1927 {
1928 	struct __sctp_missing report;
1929 	__u16 len;
1930 
1931 	len = SCTP_PAD4(sizeof(report));
1932 
1933 	/* Make an ERROR chunk, preparing enough room for
1934 	 * returning multiple unknown parameters.
1935 	 */
1936 	if (!*errp)
1937 		*errp = sctp_make_op_error_space(asoc, chunk, len);
1938 
1939 	if (*errp) {
1940 		report.num_missing = htonl(1);
1941 		report.type = paramtype;
1942 		sctp_init_cause(*errp, SCTP_ERROR_MISS_PARAM,
1943 				sizeof(report));
1944 		sctp_addto_chunk(*errp, sizeof(report), &report);
1945 	}
1946 
1947 	/* Stop processing this chunk. */
1948 	return 0;
1949 }
1950 
1951 /* Report an Invalid Mandatory Parameter.  */
sctp_process_inv_mandatory(const struct sctp_association * asoc,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1952 static int sctp_process_inv_mandatory(const struct sctp_association *asoc,
1953 				      struct sctp_chunk *chunk,
1954 				      struct sctp_chunk **errp)
1955 {
1956 	/* Invalid Mandatory Parameter Error has no payload. */
1957 
1958 	if (!*errp)
1959 		*errp = sctp_make_op_error_space(asoc, chunk, 0);
1960 
1961 	if (*errp)
1962 		sctp_init_cause(*errp, SCTP_ERROR_INV_PARAM, 0);
1963 
1964 	/* Stop processing this chunk. */
1965 	return 0;
1966 }
1967 
sctp_process_inv_paramlength(const struct sctp_association * asoc,struct sctp_paramhdr * param,const struct sctp_chunk * chunk,struct sctp_chunk ** errp)1968 static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
1969 					struct sctp_paramhdr *param,
1970 					const struct sctp_chunk *chunk,
1971 					struct sctp_chunk **errp)
1972 {
1973 	/* This is a fatal error.  Any accumulated non-fatal errors are
1974 	 * not reported.
1975 	 */
1976 	if (*errp)
1977 		sctp_chunk_free(*errp);
1978 
1979 	/* Create an error chunk and fill it in with our payload. */
1980 	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
1981 
1982 	return 0;
1983 }
1984 
1985 
1986 /* Do not attempt to handle the HOST_NAME parm.  However, do
1987  * send back an indicator to the peer.
1988  */
sctp_process_hn_param(const struct sctp_association * asoc,union sctp_params param,struct sctp_chunk * chunk,struct sctp_chunk ** errp)1989 static int sctp_process_hn_param(const struct sctp_association *asoc,
1990 				 union sctp_params param,
1991 				 struct sctp_chunk *chunk,
1992 				 struct sctp_chunk **errp)
1993 {
1994 	__u16 len = ntohs(param.p->length);
1995 
1996 	/* Processing of the HOST_NAME parameter will generate an
1997 	 * ABORT.  If we've accumulated any non-fatal errors, they
1998 	 * would be unrecognized parameters and we should not include
1999 	 * them in the ABORT.
2000 	 */
2001 	if (*errp)
2002 		sctp_chunk_free(*errp);
2003 
2004 	*errp = sctp_make_op_error(asoc, chunk, SCTP_ERROR_DNS_FAILED,
2005 				   param.v, len, 0);
2006 
2007 	/* Stop processing this chunk. */
2008 	return 0;
2009 }
2010 
sctp_verify_ext_param(struct net * net,const struct sctp_endpoint * ep,union sctp_params param)2011 static int sctp_verify_ext_param(struct net *net,
2012 				 const struct sctp_endpoint *ep,
2013 				 union sctp_params param)
2014 {
2015 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2016 	int have_asconf = 0;
2017 	int have_auth = 0;
2018 	int i;
2019 
2020 	for (i = 0; i < num_ext; i++) {
2021 		switch (param.ext->chunks[i]) {
2022 		case SCTP_CID_AUTH:
2023 			have_auth = 1;
2024 			break;
2025 		case SCTP_CID_ASCONF:
2026 		case SCTP_CID_ASCONF_ACK:
2027 			have_asconf = 1;
2028 			break;
2029 		}
2030 	}
2031 
2032 	/* ADD-IP Security: The draft requires us to ABORT or ignore the
2033 	 * INIT/INIT-ACK if ADD-IP is listed, but AUTH is not.  Do this
2034 	 * only if ADD-IP is turned on and we are not backward-compatible
2035 	 * mode.
2036 	 */
2037 	if (net->sctp.addip_noauth)
2038 		return 1;
2039 
2040 	if (ep->asconf_enable && !have_auth && have_asconf)
2041 		return 0;
2042 
2043 	return 1;
2044 }
2045 
sctp_process_ext_param(struct sctp_association * asoc,union sctp_params param)2046 static void sctp_process_ext_param(struct sctp_association *asoc,
2047 				   union sctp_params param)
2048 {
2049 	__u16 num_ext = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2050 	int i;
2051 
2052 	for (i = 0; i < num_ext; i++) {
2053 		switch (param.ext->chunks[i]) {
2054 		case SCTP_CID_RECONF:
2055 			if (asoc->ep->reconf_enable)
2056 				asoc->peer.reconf_capable = 1;
2057 			break;
2058 		case SCTP_CID_FWD_TSN:
2059 			if (asoc->ep->prsctp_enable)
2060 				asoc->peer.prsctp_capable = 1;
2061 			break;
2062 		case SCTP_CID_AUTH:
2063 			/* if the peer reports AUTH, assume that he
2064 			 * supports AUTH.
2065 			 */
2066 			if (asoc->ep->auth_enable)
2067 				asoc->peer.auth_capable = 1;
2068 			break;
2069 		case SCTP_CID_ASCONF:
2070 		case SCTP_CID_ASCONF_ACK:
2071 			if (asoc->ep->asconf_enable)
2072 				asoc->peer.asconf_capable = 1;
2073 			break;
2074 		case SCTP_CID_I_DATA:
2075 			if (asoc->ep->intl_enable)
2076 				asoc->peer.intl_capable = 1;
2077 			break;
2078 		default:
2079 			break;
2080 		}
2081 	}
2082 }
2083 
2084 /* RFC 3.2.1 & the Implementers Guide 2.2.
2085  *
2086  * The Parameter Types are encoded such that the
2087  * highest-order two bits specify the action that must be
2088  * taken if the processing endpoint does not recognize the
2089  * Parameter Type.
2090  *
2091  * 00 - Stop processing this parameter; do not process any further
2092  * 	parameters within this chunk
2093  *
2094  * 01 - Stop processing this parameter, do not process any further
2095  *	parameters within this chunk, and report the unrecognized
2096  *	parameter in an 'Unrecognized Parameter' ERROR chunk.
2097  *
2098  * 10 - Skip this parameter and continue processing.
2099  *
2100  * 11 - Skip this parameter and continue processing but
2101  *	report the unrecognized parameter in an
2102  *	'Unrecognized Parameter' ERROR chunk.
2103  *
2104  * Return value:
2105  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2106  * 	SCTP_IERROR_ERROR    - stop and report an error.
2107  * 	SCTP_IERROR_NOMEME   - out of memory.
2108  */
sctp_process_unk_param(const struct sctp_association * asoc,union sctp_params param,struct sctp_chunk * chunk,struct sctp_chunk ** errp)2109 static enum sctp_ierror sctp_process_unk_param(
2110 					const struct sctp_association *asoc,
2111 					union sctp_params param,
2112 					struct sctp_chunk *chunk,
2113 					struct sctp_chunk **errp)
2114 {
2115 	int retval = SCTP_IERROR_NO_ERROR;
2116 
2117 	switch (param.p->type & SCTP_PARAM_ACTION_MASK) {
2118 	case SCTP_PARAM_ACTION_DISCARD:
2119 		retval =  SCTP_IERROR_ERROR;
2120 		break;
2121 	case SCTP_PARAM_ACTION_SKIP:
2122 		break;
2123 	case SCTP_PARAM_ACTION_DISCARD_ERR:
2124 		retval =  SCTP_IERROR_ERROR;
2125 		fallthrough;
2126 	case SCTP_PARAM_ACTION_SKIP_ERR:
2127 		/* Make an ERROR chunk, preparing enough room for
2128 		 * returning multiple unknown parameters.
2129 		 */
2130 		if (!*errp) {
2131 			*errp = sctp_make_op_error_limited(asoc, chunk);
2132 			if (!*errp) {
2133 				/* If there is no memory for generating the
2134 				 * ERROR report as specified, an ABORT will be
2135 				 * triggered to the peer and the association
2136 				 * won't be established.
2137 				 */
2138 				retval = SCTP_IERROR_NOMEM;
2139 				break;
2140 			}
2141 		}
2142 
2143 		if (!sctp_init_cause(*errp, SCTP_ERROR_UNKNOWN_PARAM,
2144 				     ntohs(param.p->length)))
2145 			sctp_addto_chunk(*errp, ntohs(param.p->length),
2146 					 param.v);
2147 		break;
2148 	default:
2149 		break;
2150 	}
2151 
2152 	return retval;
2153 }
2154 
2155 /* Verify variable length parameters
2156  * Return values:
2157  * 	SCTP_IERROR_ABORT - trigger an ABORT
2158  * 	SCTP_IERROR_NOMEM - out of memory (abort)
2159  *	SCTP_IERROR_ERROR - stop processing, trigger an ERROR
2160  * 	SCTP_IERROR_NO_ERROR - continue with the chunk
2161  */
sctp_verify_param(struct net * net,const struct sctp_endpoint * ep,const struct sctp_association * asoc,union sctp_params param,enum sctp_cid cid,struct sctp_chunk * chunk,struct sctp_chunk ** err_chunk)2162 static enum sctp_ierror sctp_verify_param(struct net *net,
2163 					  const struct sctp_endpoint *ep,
2164 					  const struct sctp_association *asoc,
2165 					  union sctp_params param,
2166 					  enum sctp_cid cid,
2167 					  struct sctp_chunk *chunk,
2168 					  struct sctp_chunk **err_chunk)
2169 {
2170 	struct sctp_hmac_algo_param *hmacs;
2171 	int retval = SCTP_IERROR_NO_ERROR;
2172 	__u16 n_elt, id = 0;
2173 	int i;
2174 
2175 	/* FIXME - This routine is not looking at each parameter per the
2176 	 * chunk type, i.e., unrecognized parameters should be further
2177 	 * identified based on the chunk id.
2178 	 */
2179 
2180 	switch (param.p->type) {
2181 	case SCTP_PARAM_IPV4_ADDRESS:
2182 	case SCTP_PARAM_IPV6_ADDRESS:
2183 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2184 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2185 	case SCTP_PARAM_STATE_COOKIE:
2186 	case SCTP_PARAM_HEARTBEAT_INFO:
2187 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2188 	case SCTP_PARAM_ECN_CAPABLE:
2189 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2190 		break;
2191 
2192 	case SCTP_PARAM_SUPPORTED_EXT:
2193 		if (!sctp_verify_ext_param(net, ep, param))
2194 			return SCTP_IERROR_ABORT;
2195 		break;
2196 
2197 	case SCTP_PARAM_SET_PRIMARY:
2198 		if (!ep->asconf_enable)
2199 			goto unhandled;
2200 
2201 		if (ntohs(param.p->length) < sizeof(struct sctp_addip_param) +
2202 					     sizeof(struct sctp_paramhdr)) {
2203 			sctp_process_inv_paramlength(asoc, param.p,
2204 						     chunk, err_chunk);
2205 			retval = SCTP_IERROR_ABORT;
2206 		}
2207 		break;
2208 
2209 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2210 		/* Tell the peer, we won't support this param.  */
2211 		sctp_process_hn_param(asoc, param, chunk, err_chunk);
2212 		retval = SCTP_IERROR_ABORT;
2213 		break;
2214 
2215 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2216 		if (ep->prsctp_enable)
2217 			break;
2218 		goto unhandled;
2219 
2220 	case SCTP_PARAM_RANDOM:
2221 		if (!ep->auth_enable)
2222 			goto unhandled;
2223 
2224 		/* SCTP-AUTH: Secion 6.1
2225 		 * If the random number is not 32 byte long the association
2226 		 * MUST be aborted.  The ABORT chunk SHOULD contain the error
2227 		 * cause 'Protocol Violation'.
2228 		 */
2229 		if (SCTP_AUTH_RANDOM_LENGTH != ntohs(param.p->length) -
2230 					       sizeof(struct sctp_paramhdr)) {
2231 			sctp_process_inv_paramlength(asoc, param.p,
2232 						     chunk, err_chunk);
2233 			retval = SCTP_IERROR_ABORT;
2234 		}
2235 		break;
2236 
2237 	case SCTP_PARAM_CHUNKS:
2238 		if (!ep->auth_enable)
2239 			goto unhandled;
2240 
2241 		/* SCTP-AUTH: Section 3.2
2242 		 * The CHUNKS parameter MUST be included once in the INIT or
2243 		 *  INIT-ACK chunk if the sender wants to receive authenticated
2244 		 *  chunks.  Its maximum length is 260 bytes.
2245 		 */
2246 		if (260 < ntohs(param.p->length)) {
2247 			sctp_process_inv_paramlength(asoc, param.p,
2248 						     chunk, err_chunk);
2249 			retval = SCTP_IERROR_ABORT;
2250 		}
2251 		break;
2252 
2253 	case SCTP_PARAM_HMAC_ALGO:
2254 		if (!ep->auth_enable)
2255 			goto unhandled;
2256 
2257 		hmacs = (struct sctp_hmac_algo_param *)param.p;
2258 		n_elt = (ntohs(param.p->length) -
2259 			 sizeof(struct sctp_paramhdr)) >> 1;
2260 
2261 		/* SCTP-AUTH: Section 6.1
2262 		 * The HMAC algorithm based on SHA-1 MUST be supported and
2263 		 * included in the HMAC-ALGO parameter.
2264 		 */
2265 		for (i = 0; i < n_elt; i++) {
2266 			id = ntohs(hmacs->hmac_ids[i]);
2267 
2268 			if (id == SCTP_AUTH_HMAC_ID_SHA1)
2269 				break;
2270 		}
2271 
2272 		if (id != SCTP_AUTH_HMAC_ID_SHA1) {
2273 			sctp_process_inv_paramlength(asoc, param.p, chunk,
2274 						     err_chunk);
2275 			retval = SCTP_IERROR_ABORT;
2276 		}
2277 		break;
2278 unhandled:
2279 	default:
2280 		pr_debug("%s: unrecognized param:%d for chunk:%d\n",
2281 			 __func__, ntohs(param.p->type), cid);
2282 
2283 		retval = sctp_process_unk_param(asoc, param, chunk, err_chunk);
2284 		break;
2285 	}
2286 	return retval;
2287 }
2288 
2289 /* Verify the INIT packet before we process it.  */
sctp_verify_init(struct net * net,const struct sctp_endpoint * ep,const struct sctp_association * asoc,enum sctp_cid cid,struct sctp_init_chunk * peer_init,struct sctp_chunk * chunk,struct sctp_chunk ** errp)2290 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
2291 		     const struct sctp_association *asoc, enum sctp_cid cid,
2292 		     struct sctp_init_chunk *peer_init,
2293 		     struct sctp_chunk *chunk, struct sctp_chunk **errp)
2294 {
2295 	union sctp_params param;
2296 	bool has_cookie = false;
2297 	int result;
2298 
2299 	/* Check for missing mandatory parameters. Note: Initial TSN is
2300 	 * also mandatory, but is not checked here since the valid range
2301 	 * is 0..2**32-1. RFC4960, section 3.3.3.
2302 	 */
2303 	if (peer_init->init_hdr.num_outbound_streams == 0 ||
2304 	    peer_init->init_hdr.num_inbound_streams == 0 ||
2305 	    peer_init->init_hdr.init_tag == 0 ||
2306 	    ntohl(peer_init->init_hdr.a_rwnd) < SCTP_DEFAULT_MINWINDOW)
2307 		return sctp_process_inv_mandatory(asoc, chunk, errp);
2308 
2309 	sctp_walk_params(param, peer_init, init_hdr.params) {
2310 		if (param.p->type == SCTP_PARAM_STATE_COOKIE)
2311 			has_cookie = true;
2312 	}
2313 
2314 	/* There is a possibility that a parameter length was bad and
2315 	 * in that case we would have stoped walking the parameters.
2316 	 * The current param.p would point at the bad one.
2317 	 * Current consensus on the mailing list is to generate a PROTOCOL
2318 	 * VIOLATION error.  We build the ERROR chunk here and let the normal
2319 	 * error handling code build and send the packet.
2320 	 */
2321 	if (param.v != (void *)chunk->chunk_end)
2322 		return sctp_process_inv_paramlength(asoc, param.p, chunk, errp);
2323 
2324 	/* The only missing mandatory param possible today is
2325 	 * the state cookie for an INIT-ACK chunk.
2326 	 */
2327 	if ((SCTP_CID_INIT_ACK == cid) && !has_cookie)
2328 		return sctp_process_missing_param(asoc, SCTP_PARAM_STATE_COOKIE,
2329 						  chunk, errp);
2330 
2331 	/* Verify all the variable length parameters */
2332 	sctp_walk_params(param, peer_init, init_hdr.params) {
2333 		result = sctp_verify_param(net, ep, asoc, param, cid,
2334 					   chunk, errp);
2335 		switch (result) {
2336 		case SCTP_IERROR_ABORT:
2337 		case SCTP_IERROR_NOMEM:
2338 			return 0;
2339 		case SCTP_IERROR_ERROR:
2340 			return 1;
2341 		case SCTP_IERROR_NO_ERROR:
2342 		default:
2343 			break;
2344 		}
2345 
2346 	} /* for (loop through all parameters) */
2347 
2348 	return 1;
2349 }
2350 
2351 /* Unpack the parameters in an INIT packet into an association.
2352  * Returns 0 on failure, else success.
2353  * FIXME:  This is an association method.
2354  */
sctp_process_init(struct sctp_association * asoc,struct sctp_chunk * chunk,const union sctp_addr * peer_addr,struct sctp_init_chunk * peer_init,gfp_t gfp)2355 int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,
2356 		      const union sctp_addr *peer_addr,
2357 		      struct sctp_init_chunk *peer_init, gfp_t gfp)
2358 {
2359 	struct sctp_transport *transport;
2360 	struct list_head *pos, *temp;
2361 	union sctp_params param;
2362 	union sctp_addr addr;
2363 	struct sctp_af *af;
2364 	int src_match = 0;
2365 
2366 	/* We must include the address that the INIT packet came from.
2367 	 * This is the only address that matters for an INIT packet.
2368 	 * When processing a COOKIE ECHO, we retrieve the from address
2369 	 * of the INIT from the cookie.
2370 	 */
2371 
2372 	/* This implementation defaults to making the first transport
2373 	 * added as the primary transport.  The source address seems to
2374 	 * be a better choice than any of the embedded addresses.
2375 	 */
2376 	asoc->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
2377 	if (!sctp_assoc_add_peer(asoc, peer_addr, gfp, SCTP_ACTIVE))
2378 		goto nomem;
2379 
2380 	if (sctp_cmp_addr_exact(sctp_source(chunk), peer_addr))
2381 		src_match = 1;
2382 
2383 	/* Process the initialization parameters.  */
2384 	sctp_walk_params(param, peer_init, init_hdr.params) {
2385 		if (!src_match &&
2386 		    (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
2387 		     param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
2388 			af = sctp_get_af_specific(param_type2af(param.p->type));
2389 			if (!af->from_addr_param(&addr, param.addr,
2390 						 chunk->sctp_hdr->source, 0))
2391 				continue;
2392 			if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
2393 				src_match = 1;
2394 		}
2395 
2396 		if (!sctp_process_param(asoc, param, peer_addr, gfp))
2397 			goto clean_up;
2398 	}
2399 
2400 	/* source address of chunk may not match any valid address */
2401 	if (!src_match)
2402 		goto clean_up;
2403 
2404 	/* AUTH: After processing the parameters, make sure that we
2405 	 * have all the required info to potentially do authentications.
2406 	 */
2407 	if (asoc->peer.auth_capable && (!asoc->peer.peer_random ||
2408 					!asoc->peer.peer_hmacs))
2409 		asoc->peer.auth_capable = 0;
2410 
2411 	/* In a non-backward compatible mode, if the peer claims
2412 	 * support for ADD-IP but not AUTH,  the ADD-IP spec states
2413 	 * that we MUST ABORT the association. Section 6.  The section
2414 	 * also give us an option to silently ignore the packet, which
2415 	 * is what we'll do here.
2416 	 */
2417 	if (!asoc->base.net->sctp.addip_noauth &&
2418 	    (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
2419 		asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
2420 						  SCTP_PARAM_DEL_IP |
2421 						  SCTP_PARAM_SET_PRIMARY);
2422 		asoc->peer.asconf_capable = 0;
2423 		goto clean_up;
2424 	}
2425 
2426 	/* Walk list of transports, removing transports in the UNKNOWN state. */
2427 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2428 		transport = list_entry(pos, struct sctp_transport, transports);
2429 		if (transport->state == SCTP_UNKNOWN) {
2430 			sctp_assoc_rm_peer(asoc, transport);
2431 		}
2432 	}
2433 
2434 	/* The fixed INIT headers are always in network byte
2435 	 * order.
2436 	 */
2437 	asoc->peer.i.init_tag =
2438 		ntohl(peer_init->init_hdr.init_tag);
2439 	asoc->peer.i.a_rwnd =
2440 		ntohl(peer_init->init_hdr.a_rwnd);
2441 	asoc->peer.i.num_outbound_streams =
2442 		ntohs(peer_init->init_hdr.num_outbound_streams);
2443 	asoc->peer.i.num_inbound_streams =
2444 		ntohs(peer_init->init_hdr.num_inbound_streams);
2445 	asoc->peer.i.initial_tsn =
2446 		ntohl(peer_init->init_hdr.initial_tsn);
2447 
2448 	asoc->strreset_inseq = asoc->peer.i.initial_tsn;
2449 
2450 	/* Apply the upper bounds for output streams based on peer's
2451 	 * number of inbound streams.
2452 	 */
2453 	if (asoc->c.sinit_num_ostreams  >
2454 	    ntohs(peer_init->init_hdr.num_inbound_streams)) {
2455 		asoc->c.sinit_num_ostreams =
2456 			ntohs(peer_init->init_hdr.num_inbound_streams);
2457 	}
2458 
2459 	if (asoc->c.sinit_max_instreams >
2460 	    ntohs(peer_init->init_hdr.num_outbound_streams)) {
2461 		asoc->c.sinit_max_instreams =
2462 			ntohs(peer_init->init_hdr.num_outbound_streams);
2463 	}
2464 
2465 	/* Copy Initiation tag from INIT to VT_peer in cookie.   */
2466 	asoc->c.peer_vtag = asoc->peer.i.init_tag;
2467 
2468 	/* Peer Rwnd   : Current calculated value of the peer's rwnd.  */
2469 	asoc->peer.rwnd = asoc->peer.i.a_rwnd;
2470 
2471 	/* RFC 2960 7.2.1 The initial value of ssthresh MAY be arbitrarily
2472 	 * high (for example, implementations MAY use the size of the receiver
2473 	 * advertised window).
2474 	 */
2475 	list_for_each_entry(transport, &asoc->peer.transport_addr_list,
2476 			transports) {
2477 		transport->ssthresh = asoc->peer.i.a_rwnd;
2478 	}
2479 
2480 	/* Set up the TSN tracking pieces.  */
2481 	if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
2482 				asoc->peer.i.initial_tsn, gfp))
2483 		goto clean_up;
2484 
2485 	/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
2486 	 *
2487 	 * The stream sequence number in all the streams shall start
2488 	 * from 0 when the association is established.  Also, when the
2489 	 * stream sequence number reaches the value 65535 the next
2490 	 * stream sequence number shall be set to 0.
2491 	 */
2492 
2493 	if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams,
2494 			     asoc->c.sinit_max_instreams, gfp))
2495 		goto clean_up;
2496 
2497 	/* Update frag_point when stream_interleave may get changed. */
2498 	sctp_assoc_update_frag_point(asoc);
2499 
2500 	if (!asoc->temp && sctp_assoc_set_id(asoc, gfp))
2501 		goto clean_up;
2502 
2503 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2504 	 *
2505 	 * When an endpoint has an ASCONF signaled change to be sent to the
2506 	 * remote endpoint it should do the following:
2507 	 * ...
2508 	 * A2) A serial number should be assigned to the Chunk. The serial
2509 	 * number should be a monotonically increasing number. All serial
2510 	 * numbers are defined to be initialized at the start of the
2511 	 * association to the same value as the Initial TSN.
2512 	 */
2513 	asoc->peer.addip_serial = asoc->peer.i.initial_tsn - 1;
2514 	return 1;
2515 
2516 clean_up:
2517 	/* Release the transport structures. */
2518 	list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) {
2519 		transport = list_entry(pos, struct sctp_transport, transports);
2520 		if (transport->state != SCTP_ACTIVE)
2521 			sctp_assoc_rm_peer(asoc, transport);
2522 	}
2523 
2524 nomem:
2525 	return 0;
2526 }
2527 
2528 
2529 /* Update asoc with the option described in param.
2530  *
2531  * RFC2960 3.3.2.1 Optional/Variable Length Parameters in INIT
2532  *
2533  * asoc is the association to update.
2534  * param is the variable length parameter to use for update.
2535  * cid tells us if this is an INIT, INIT ACK or COOKIE ECHO.
2536  * If the current packet is an INIT we want to minimize the amount of
2537  * work we do.  In particular, we should not build transport
2538  * structures for the addresses.
2539  */
sctp_process_param(struct sctp_association * asoc,union sctp_params param,const union sctp_addr * peer_addr,gfp_t gfp)2540 static int sctp_process_param(struct sctp_association *asoc,
2541 			      union sctp_params param,
2542 			      const union sctp_addr *peer_addr,
2543 			      gfp_t gfp)
2544 {
2545 	struct sctp_endpoint *ep = asoc->ep;
2546 	union sctp_addr_param *addr_param;
2547 	struct net *net = asoc->base.net;
2548 	struct sctp_transport *t;
2549 	enum sctp_scope scope;
2550 	union sctp_addr addr;
2551 	struct sctp_af *af;
2552 	int retval = 1, i;
2553 	u32 stale;
2554 	__u16 sat;
2555 
2556 	/* We maintain all INIT parameters in network byte order all the
2557 	 * time.  This allows us to not worry about whether the parameters
2558 	 * came from a fresh INIT, and INIT ACK, or were stored in a cookie.
2559 	 */
2560 	switch (param.p->type) {
2561 	case SCTP_PARAM_IPV6_ADDRESS:
2562 		if (PF_INET6 != asoc->base.sk->sk_family)
2563 			break;
2564 		goto do_addr_param;
2565 
2566 	case SCTP_PARAM_IPV4_ADDRESS:
2567 		/* v4 addresses are not allowed on v6-only socket */
2568 		if (ipv6_only_sock(asoc->base.sk))
2569 			break;
2570 do_addr_param:
2571 		af = sctp_get_af_specific(param_type2af(param.p->type));
2572 		if (!af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0))
2573 			break;
2574 		scope = sctp_scope(peer_addr);
2575 		if (sctp_in_scope(net, &addr, scope))
2576 			if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
2577 				return 0;
2578 		break;
2579 
2580 	case SCTP_PARAM_COOKIE_PRESERVATIVE:
2581 		if (!net->sctp.cookie_preserve_enable)
2582 			break;
2583 
2584 		stale = ntohl(param.life->lifespan_increment);
2585 
2586 		/* Suggested Cookie Life span increment's unit is msec,
2587 		 * (1/1000sec).
2588 		 */
2589 		asoc->cookie_life = ktime_add_ms(asoc->cookie_life, stale);
2590 		break;
2591 
2592 	case SCTP_PARAM_HOST_NAME_ADDRESS:
2593 		pr_debug("%s: unimplemented SCTP_HOST_NAME_ADDRESS\n", __func__);
2594 		break;
2595 
2596 	case SCTP_PARAM_SUPPORTED_ADDRESS_TYPES:
2597 		/* Turn off the default values first so we'll know which
2598 		 * ones are really set by the peer.
2599 		 */
2600 		asoc->peer.ipv4_address = 0;
2601 		asoc->peer.ipv6_address = 0;
2602 
2603 		/* Assume that peer supports the address family
2604 		 * by which it sends a packet.
2605 		 */
2606 		if (peer_addr->sa.sa_family == AF_INET6)
2607 			asoc->peer.ipv6_address = 1;
2608 		else if (peer_addr->sa.sa_family == AF_INET)
2609 			asoc->peer.ipv4_address = 1;
2610 
2611 		/* Cycle through address types; avoid divide by 0. */
2612 		sat = ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2613 		if (sat)
2614 			sat /= sizeof(__u16);
2615 
2616 		for (i = 0; i < sat; ++i) {
2617 			switch (param.sat->types[i]) {
2618 			case SCTP_PARAM_IPV4_ADDRESS:
2619 				asoc->peer.ipv4_address = 1;
2620 				break;
2621 
2622 			case SCTP_PARAM_IPV6_ADDRESS:
2623 				if (PF_INET6 == asoc->base.sk->sk_family)
2624 					asoc->peer.ipv6_address = 1;
2625 				break;
2626 
2627 			case SCTP_PARAM_HOST_NAME_ADDRESS:
2628 				asoc->peer.hostname_address = 1;
2629 				break;
2630 
2631 			default: /* Just ignore anything else.  */
2632 				break;
2633 			}
2634 		}
2635 		break;
2636 
2637 	case SCTP_PARAM_STATE_COOKIE:
2638 		asoc->peer.cookie_len =
2639 			ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
2640 		kfree(asoc->peer.cookie);
2641 		asoc->peer.cookie = kmemdup(param.cookie->body, asoc->peer.cookie_len, gfp);
2642 		if (!asoc->peer.cookie)
2643 			retval = 0;
2644 		break;
2645 
2646 	case SCTP_PARAM_HEARTBEAT_INFO:
2647 		/* Would be odd to receive, but it causes no problems. */
2648 		break;
2649 
2650 	case SCTP_PARAM_UNRECOGNIZED_PARAMETERS:
2651 		/* Rejected during verify stage. */
2652 		break;
2653 
2654 	case SCTP_PARAM_ECN_CAPABLE:
2655 		if (asoc->ep->ecn_enable) {
2656 			asoc->peer.ecn_capable = 1;
2657 			break;
2658 		}
2659 		/* Fall Through */
2660 		goto fall_through;
2661 
2662 
2663 	case SCTP_PARAM_ADAPTATION_LAYER_IND:
2664 		asoc->peer.adaptation_ind = ntohl(param.aind->adaptation_ind);
2665 		break;
2666 
2667 	case SCTP_PARAM_SET_PRIMARY:
2668 		if (!ep->asconf_enable)
2669 			goto fall_through;
2670 
2671 		addr_param = param.v + sizeof(struct sctp_addip_param);
2672 
2673 		af = sctp_get_af_specific(param_type2af(addr_param->p.type));
2674 		if (!af)
2675 			break;
2676 
2677 		if (!af->from_addr_param(&addr, addr_param,
2678 					 htons(asoc->peer.port), 0))
2679 			break;
2680 
2681 		if (!af->addr_valid(&addr, NULL, NULL))
2682 			break;
2683 
2684 		t = sctp_assoc_lookup_paddr(asoc, &addr);
2685 		if (!t)
2686 			break;
2687 
2688 		sctp_assoc_set_primary(asoc, t);
2689 		break;
2690 
2691 	case SCTP_PARAM_SUPPORTED_EXT:
2692 		sctp_process_ext_param(asoc, param);
2693 		break;
2694 
2695 	case SCTP_PARAM_FWD_TSN_SUPPORT:
2696 		if (asoc->ep->prsctp_enable) {
2697 			asoc->peer.prsctp_capable = 1;
2698 			break;
2699 		}
2700 		/* Fall Through */
2701 		goto fall_through;
2702 
2703 	case SCTP_PARAM_RANDOM:
2704 		if (!ep->auth_enable)
2705 			goto fall_through;
2706 
2707 		/* Save peer's random parameter */
2708 		kfree(asoc->peer.peer_random);
2709 		asoc->peer.peer_random = kmemdup(param.p,
2710 					    ntohs(param.p->length), gfp);
2711 		if (!asoc->peer.peer_random) {
2712 			retval = 0;
2713 			break;
2714 		}
2715 		break;
2716 
2717 	case SCTP_PARAM_HMAC_ALGO:
2718 		if (!ep->auth_enable)
2719 			goto fall_through;
2720 
2721 		/* Save peer's HMAC list */
2722 		kfree(asoc->peer.peer_hmacs);
2723 		asoc->peer.peer_hmacs = kmemdup(param.p,
2724 					    ntohs(param.p->length), gfp);
2725 		if (!asoc->peer.peer_hmacs) {
2726 			retval = 0;
2727 			break;
2728 		}
2729 
2730 		/* Set the default HMAC the peer requested*/
2731 		sctp_auth_asoc_set_default_hmac(asoc, param.hmac_algo);
2732 		break;
2733 
2734 	case SCTP_PARAM_CHUNKS:
2735 		if (!ep->auth_enable)
2736 			goto fall_through;
2737 
2738 		kfree(asoc->peer.peer_chunks);
2739 		asoc->peer.peer_chunks = kmemdup(param.p,
2740 					    ntohs(param.p->length), gfp);
2741 		if (!asoc->peer.peer_chunks)
2742 			retval = 0;
2743 		break;
2744 fall_through:
2745 	default:
2746 		/* Any unrecognized parameters should have been caught
2747 		 * and handled by sctp_verify_param() which should be
2748 		 * called prior to this routine.  Simply log the error
2749 		 * here.
2750 		 */
2751 		pr_debug("%s: ignoring param:%d for association:%p.\n",
2752 			 __func__, ntohs(param.p->type), asoc);
2753 		break;
2754 	}
2755 
2756 	return retval;
2757 }
2758 
2759 /* Select a new verification tag.  */
sctp_generate_tag(const struct sctp_endpoint * ep)2760 __u32 sctp_generate_tag(const struct sctp_endpoint *ep)
2761 {
2762 	/* I believe that this random number generator complies with RFC1750.
2763 	 * A tag of 0 is reserved for special cases (e.g. INIT).
2764 	 */
2765 	__u32 x;
2766 
2767 	do {
2768 		get_random_bytes(&x, sizeof(__u32));
2769 	} while (x == 0);
2770 
2771 	return x;
2772 }
2773 
2774 /* Select an initial TSN to send during startup.  */
sctp_generate_tsn(const struct sctp_endpoint * ep)2775 __u32 sctp_generate_tsn(const struct sctp_endpoint *ep)
2776 {
2777 	__u32 retval;
2778 
2779 	get_random_bytes(&retval, sizeof(__u32));
2780 	return retval;
2781 }
2782 
2783 /*
2784  * ADDIP 3.1.1 Address Configuration Change Chunk (ASCONF)
2785  *      0                   1                   2                   3
2786  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2787  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2788  *     | Type = 0xC1   |  Chunk Flags  |      Chunk Length             |
2789  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2790  *     |                       Serial Number                           |
2791  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2792  *     |                    Address Parameter                          |
2793  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2794  *     |                     ASCONF Parameter #1                       |
2795  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2796  *     \                                                               \
2797  *     /                             ....                              /
2798  *     \                                                               \
2799  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2800  *     |                     ASCONF Parameter #N                       |
2801  *      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2802  *
2803  * Address Parameter and other parameter will not be wrapped in this function
2804  */
sctp_make_asconf(struct sctp_association * asoc,union sctp_addr * addr,int vparam_len)2805 static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
2806 					   union sctp_addr *addr,
2807 					   int vparam_len)
2808 {
2809 	struct sctp_addiphdr asconf;
2810 	struct sctp_chunk *retval;
2811 	int length = sizeof(asconf) + vparam_len;
2812 	union sctp_addr_param addrparam;
2813 	int addrlen;
2814 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2815 
2816 	addrlen = af->to_addr_param(addr, &addrparam);
2817 	if (!addrlen)
2818 		return NULL;
2819 	length += addrlen;
2820 
2821 	/* Create the chunk.  */
2822 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
2823 				   GFP_ATOMIC);
2824 	if (!retval)
2825 		return NULL;
2826 
2827 	asconf.serial = htonl(asoc->addip_serial++);
2828 
2829 	retval->subh.addip_hdr =
2830 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
2831 	retval->param_hdr.v =
2832 		sctp_addto_chunk(retval, addrlen, &addrparam);
2833 
2834 	return retval;
2835 }
2836 
2837 /* ADDIP
2838  * 3.2.1 Add IP Address
2839  * 	0                   1                   2                   3
2840  * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2841  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2842  *     |        Type = 0xC001          |    Length = Variable          |
2843  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2844  *     |               ASCONF-Request Correlation ID                   |
2845  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2846  *     |                       Address Parameter                       |
2847  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2848  *
2849  * 3.2.2 Delete IP Address
2850  * 	0                   1                   2                   3
2851  * 	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2852  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2853  *     |        Type = 0xC002          |    Length = Variable          |
2854  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2855  *     |               ASCONF-Request Correlation ID                   |
2856  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2857  *     |                       Address Parameter                       |
2858  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2859  *
2860  */
sctp_make_asconf_update_ip(struct sctp_association * asoc,union sctp_addr * laddr,struct sockaddr * addrs,int addrcnt,__be16 flags)2861 struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *asoc,
2862 					      union sctp_addr *laddr,
2863 					      struct sockaddr *addrs,
2864 					      int addrcnt, __be16 flags)
2865 {
2866 	union sctp_addr_param addr_param;
2867 	struct sctp_addip_param	param;
2868 	int paramlen = sizeof(param);
2869 	struct sctp_chunk *retval;
2870 	int addr_param_len = 0;
2871 	union sctp_addr *addr;
2872 	int totallen = 0, i;
2873 	int del_pickup = 0;
2874 	struct sctp_af *af;
2875 	void *addr_buf;
2876 
2877 	/* Get total length of all the address parameters. */
2878 	addr_buf = addrs;
2879 	for (i = 0; i < addrcnt; i++) {
2880 		addr = addr_buf;
2881 		af = sctp_get_af_specific(addr->v4.sin_family);
2882 		addr_param_len = af->to_addr_param(addr, &addr_param);
2883 
2884 		totallen += paramlen;
2885 		totallen += addr_param_len;
2886 
2887 		addr_buf += af->sockaddr_len;
2888 		if (asoc->asconf_addr_del_pending && !del_pickup) {
2889 			/* reuse the parameter length from the same scope one */
2890 			totallen += paramlen;
2891 			totallen += addr_param_len;
2892 			del_pickup = 1;
2893 
2894 			pr_debug("%s: picked same-scope del_pending addr, "
2895 				 "totallen for all addresses is %d\n",
2896 				 __func__, totallen);
2897 		}
2898 	}
2899 
2900 	/* Create an asconf chunk with the required length. */
2901 	retval = sctp_make_asconf(asoc, laddr, totallen);
2902 	if (!retval)
2903 		return NULL;
2904 
2905 	/* Add the address parameters to the asconf chunk. */
2906 	addr_buf = addrs;
2907 	for (i = 0; i < addrcnt; i++) {
2908 		addr = addr_buf;
2909 		af = sctp_get_af_specific(addr->v4.sin_family);
2910 		addr_param_len = af->to_addr_param(addr, &addr_param);
2911 		param.param_hdr.type = flags;
2912 		param.param_hdr.length = htons(paramlen + addr_param_len);
2913 		param.crr_id = htonl(i);
2914 
2915 		sctp_addto_chunk(retval, paramlen, &param);
2916 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2917 
2918 		addr_buf += af->sockaddr_len;
2919 	}
2920 	if (flags == SCTP_PARAM_ADD_IP && del_pickup) {
2921 		addr = asoc->asconf_addr_del_pending;
2922 		af = sctp_get_af_specific(addr->v4.sin_family);
2923 		addr_param_len = af->to_addr_param(addr, &addr_param);
2924 		param.param_hdr.type = SCTP_PARAM_DEL_IP;
2925 		param.param_hdr.length = htons(paramlen + addr_param_len);
2926 		param.crr_id = htonl(i);
2927 
2928 		sctp_addto_chunk(retval, paramlen, &param);
2929 		sctp_addto_chunk(retval, addr_param_len, &addr_param);
2930 	}
2931 	return retval;
2932 }
2933 
2934 /* ADDIP
2935  * 3.2.4 Set Primary IP Address
2936  *	0                   1                   2                   3
2937  *	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2938  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2939  *     |        Type =0xC004           |    Length = Variable          |
2940  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2941  *     |               ASCONF-Request Correlation ID                   |
2942  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2943  *     |                       Address Parameter                       |
2944  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2945  *
2946  * Create an ASCONF chunk with Set Primary IP address parameter.
2947  */
sctp_make_asconf_set_prim(struct sctp_association * asoc,union sctp_addr * addr)2948 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
2949 					     union sctp_addr *addr)
2950 {
2951 	struct sctp_af *af = sctp_get_af_specific(addr->v4.sin_family);
2952 	union sctp_addr_param addrparam;
2953 	struct sctp_addip_param	param;
2954 	struct sctp_chunk *retval;
2955 	int len = sizeof(param);
2956 	int addrlen;
2957 
2958 	addrlen = af->to_addr_param(addr, &addrparam);
2959 	if (!addrlen)
2960 		return NULL;
2961 	len += addrlen;
2962 
2963 	/* Create the chunk and make asconf header. */
2964 	retval = sctp_make_asconf(asoc, addr, len);
2965 	if (!retval)
2966 		return NULL;
2967 
2968 	param.param_hdr.type = SCTP_PARAM_SET_PRIMARY;
2969 	param.param_hdr.length = htons(len);
2970 	param.crr_id = 0;
2971 
2972 	sctp_addto_chunk(retval, sizeof(param), &param);
2973 	sctp_addto_chunk(retval, addrlen, &addrparam);
2974 
2975 	return retval;
2976 }
2977 
2978 /* ADDIP 3.1.2 Address Configuration Acknowledgement Chunk (ASCONF-ACK)
2979  *      0                   1                   2                   3
2980  *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
2981  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2982  *     | Type = 0x80   |  Chunk Flags  |      Chunk Length             |
2983  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2984  *     |                       Serial Number                           |
2985  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2986  *     |                 ASCONF Parameter Response#1                   |
2987  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2988  *     \                                                               \
2989  *     /                             ....                              /
2990  *     \                                                               \
2991  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2992  *     |                 ASCONF Parameter Response#N                   |
2993  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2994  *
2995  * Create an ASCONF_ACK chunk with enough space for the parameter responses.
2996  */
sctp_make_asconf_ack(const struct sctp_association * asoc,__u32 serial,int vparam_len)2997 static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *asoc,
2998 					       __u32 serial, int vparam_len)
2999 {
3000 	struct sctp_addiphdr asconf;
3001 	struct sctp_chunk *retval;
3002 	int length = sizeof(asconf) + vparam_len;
3003 
3004 	/* Create the chunk.  */
3005 	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
3006 				   GFP_ATOMIC);
3007 	if (!retval)
3008 		return NULL;
3009 
3010 	asconf.serial = htonl(serial);
3011 
3012 	retval->subh.addip_hdr =
3013 		sctp_addto_chunk(retval, sizeof(asconf), &asconf);
3014 
3015 	return retval;
3016 }
3017 
3018 /* Add response parameters to an ASCONF_ACK chunk. */
sctp_add_asconf_response(struct sctp_chunk * chunk,__be32 crr_id,__be16 err_code,struct sctp_addip_param * asconf_param)3019 static void sctp_add_asconf_response(struct sctp_chunk *chunk, __be32 crr_id,
3020 				     __be16 err_code,
3021 				     struct sctp_addip_param *asconf_param)
3022 {
3023 	struct sctp_addip_param ack_param;
3024 	struct sctp_errhdr err_param;
3025 	int asconf_param_len = 0;
3026 	int err_param_len = 0;
3027 	__be16 response_type;
3028 
3029 	if (SCTP_ERROR_NO_ERROR == err_code) {
3030 		response_type = SCTP_PARAM_SUCCESS_REPORT;
3031 	} else {
3032 		response_type = SCTP_PARAM_ERR_CAUSE;
3033 		err_param_len = sizeof(err_param);
3034 		if (asconf_param)
3035 			asconf_param_len =
3036 				 ntohs(asconf_param->param_hdr.length);
3037 	}
3038 
3039 	/* Add Success Indication or Error Cause Indication parameter. */
3040 	ack_param.param_hdr.type = response_type;
3041 	ack_param.param_hdr.length = htons(sizeof(ack_param) +
3042 					   err_param_len +
3043 					   asconf_param_len);
3044 	ack_param.crr_id = crr_id;
3045 	sctp_addto_chunk(chunk, sizeof(ack_param), &ack_param);
3046 
3047 	if (SCTP_ERROR_NO_ERROR == err_code)
3048 		return;
3049 
3050 	/* Add Error Cause parameter. */
3051 	err_param.cause = err_code;
3052 	err_param.length = htons(err_param_len + asconf_param_len);
3053 	sctp_addto_chunk(chunk, err_param_len, &err_param);
3054 
3055 	/* Add the failed TLV copied from ASCONF chunk. */
3056 	if (asconf_param)
3057 		sctp_addto_chunk(chunk, asconf_param_len, asconf_param);
3058 }
3059 
3060 /* Process a asconf parameter. */
sctp_process_asconf_param(struct sctp_association * asoc,struct sctp_chunk * asconf,struct sctp_addip_param * asconf_param)3061 static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
3062 					struct sctp_chunk *asconf,
3063 					struct sctp_addip_param *asconf_param)
3064 {
3065 	union sctp_addr_param *addr_param;
3066 	struct sctp_transport *peer;
3067 	union sctp_addr	addr;
3068 	struct sctp_af *af;
3069 
3070 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3071 
3072 	if (asconf_param->param_hdr.type != SCTP_PARAM_ADD_IP &&
3073 	    asconf_param->param_hdr.type != SCTP_PARAM_DEL_IP &&
3074 	    asconf_param->param_hdr.type != SCTP_PARAM_SET_PRIMARY)
3075 		return SCTP_ERROR_UNKNOWN_PARAM;
3076 
3077 	switch (addr_param->p.type) {
3078 	case SCTP_PARAM_IPV6_ADDRESS:
3079 		if (!asoc->peer.ipv6_address)
3080 			return SCTP_ERROR_DNS_FAILED;
3081 		break;
3082 	case SCTP_PARAM_IPV4_ADDRESS:
3083 		if (!asoc->peer.ipv4_address)
3084 			return SCTP_ERROR_DNS_FAILED;
3085 		break;
3086 	default:
3087 		return SCTP_ERROR_DNS_FAILED;
3088 	}
3089 
3090 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3091 	if (unlikely(!af))
3092 		return SCTP_ERROR_DNS_FAILED;
3093 
3094 	if (!af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0))
3095 		return SCTP_ERROR_DNS_FAILED;
3096 
3097 	/* ADDIP 4.2.1  This parameter MUST NOT contain a broadcast
3098 	 * or multicast address.
3099 	 * (note: wildcard is permitted and requires special handling so
3100 	 *  make sure we check for that)
3101 	 */
3102 	if (!af->is_any(&addr) && !af->addr_valid(&addr, NULL, asconf->skb))
3103 		return SCTP_ERROR_DNS_FAILED;
3104 
3105 	switch (asconf_param->param_hdr.type) {
3106 	case SCTP_PARAM_ADD_IP:
3107 		/* Section 4.2.1:
3108 		 * If the address 0.0.0.0 or ::0 is provided, the source
3109 		 * address of the packet MUST be added.
3110 		 */
3111 		if (af->is_any(&addr))
3112 			memcpy(&addr, &asconf->source, sizeof(addr));
3113 
3114 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3115 					       SCTP_PARAM_ADD_IP,
3116 					       (struct sockaddr *)&addr,
3117 					       af->sockaddr_len))
3118 			return SCTP_ERROR_REQ_REFUSED;
3119 
3120 		/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
3121 		 * request and does not have the local resources to add this
3122 		 * new address to the association, it MUST return an Error
3123 		 * Cause TLV set to the new error code 'Operation Refused
3124 		 * Due to Resource Shortage'.
3125 		 */
3126 
3127 		peer = sctp_assoc_add_peer(asoc, &addr, GFP_ATOMIC, SCTP_UNCONFIRMED);
3128 		if (!peer)
3129 			return SCTP_ERROR_RSRC_LOW;
3130 
3131 		/* Start the heartbeat timer. */
3132 		sctp_transport_reset_hb_timer(peer);
3133 		asoc->new_transport = peer;
3134 		break;
3135 	case SCTP_PARAM_DEL_IP:
3136 		/* ADDIP 4.3 D7) If a request is received to delete the
3137 		 * last remaining IP address of a peer endpoint, the receiver
3138 		 * MUST send an Error Cause TLV with the error cause set to the
3139 		 * new error code 'Request to Delete Last Remaining IP Address'.
3140 		 */
3141 		if (asoc->peer.transport_count == 1)
3142 			return SCTP_ERROR_DEL_LAST_IP;
3143 
3144 		/* ADDIP 4.3 D8) If a request is received to delete an IP
3145 		 * address which is also the source address of the IP packet
3146 		 * which contained the ASCONF chunk, the receiver MUST reject
3147 		 * this request. To reject the request the receiver MUST send
3148 		 * an Error Cause TLV set to the new error code 'Request to
3149 		 * Delete Source IP Address'
3150 		 */
3151 		if (sctp_cmp_addr_exact(&asconf->source, &addr))
3152 			return SCTP_ERROR_DEL_SRC_IP;
3153 
3154 		/* Section 4.2.2
3155 		 * If the address 0.0.0.0 or ::0 is provided, all
3156 		 * addresses of the peer except	the source address of the
3157 		 * packet MUST be deleted.
3158 		 */
3159 		if (af->is_any(&addr)) {
3160 			sctp_assoc_set_primary(asoc, asconf->transport);
3161 			sctp_assoc_del_nonprimary_peers(asoc,
3162 							asconf->transport);
3163 			return SCTP_ERROR_NO_ERROR;
3164 		}
3165 
3166 		/* If the address is not part of the association, the
3167 		 * ASCONF-ACK with Error Cause Indication Parameter
3168 		 * which including cause of Unresolvable Address should
3169 		 * be sent.
3170 		 */
3171 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3172 		if (!peer)
3173 			return SCTP_ERROR_DNS_FAILED;
3174 
3175 		sctp_assoc_rm_peer(asoc, peer);
3176 		break;
3177 	case SCTP_PARAM_SET_PRIMARY:
3178 		/* ADDIP Section 4.2.4
3179 		 * If the address 0.0.0.0 or ::0 is provided, the receiver
3180 		 * MAY mark the source address of the packet as its
3181 		 * primary.
3182 		 */
3183 		if (af->is_any(&addr))
3184 			memcpy(&addr, sctp_source(asconf), sizeof(addr));
3185 
3186 		if (security_sctp_bind_connect(asoc->ep->base.sk,
3187 					       SCTP_PARAM_SET_PRIMARY,
3188 					       (struct sockaddr *)&addr,
3189 					       af->sockaddr_len))
3190 			return SCTP_ERROR_REQ_REFUSED;
3191 
3192 		peer = sctp_assoc_lookup_paddr(asoc, &addr);
3193 		if (!peer)
3194 			return SCTP_ERROR_DNS_FAILED;
3195 
3196 		sctp_assoc_set_primary(asoc, peer);
3197 		break;
3198 	}
3199 
3200 	return SCTP_ERROR_NO_ERROR;
3201 }
3202 
3203 /* Verify the ASCONF packet before we process it. */
sctp_verify_asconf(const struct sctp_association * asoc,struct sctp_chunk * chunk,bool addr_param_needed,struct sctp_paramhdr ** errp)3204 bool sctp_verify_asconf(const struct sctp_association *asoc,
3205 			struct sctp_chunk *chunk, bool addr_param_needed,
3206 			struct sctp_paramhdr **errp)
3207 {
3208 	struct sctp_addip_chunk *addip;
3209 	bool addr_param_seen = false;
3210 	union sctp_params param;
3211 
3212 	addip = (struct sctp_addip_chunk *)chunk->chunk_hdr;
3213 	sctp_walk_params(param, addip, addip_hdr.params) {
3214 		size_t length = ntohs(param.p->length);
3215 
3216 		*errp = param.p;
3217 		switch (param.p->type) {
3218 		case SCTP_PARAM_ERR_CAUSE:
3219 			break;
3220 		case SCTP_PARAM_IPV4_ADDRESS:
3221 			if (length != sizeof(struct sctp_ipv4addr_param))
3222 				return false;
3223 			/* ensure there is only one addr param and it's in the
3224 			 * beginning of addip_hdr params, or we reject it.
3225 			 */
3226 			if (param.v != addip->addip_hdr.params)
3227 				return false;
3228 			addr_param_seen = true;
3229 			break;
3230 		case SCTP_PARAM_IPV6_ADDRESS:
3231 			if (length != sizeof(struct sctp_ipv6addr_param))
3232 				return false;
3233 			if (param.v != addip->addip_hdr.params)
3234 				return false;
3235 			addr_param_seen = true;
3236 			break;
3237 		case SCTP_PARAM_ADD_IP:
3238 		case SCTP_PARAM_DEL_IP:
3239 		case SCTP_PARAM_SET_PRIMARY:
3240 			/* In ASCONF chunks, these need to be first. */
3241 			if (addr_param_needed && !addr_param_seen)
3242 				return false;
3243 			length = ntohs(param.addip->param_hdr.length);
3244 			if (length < sizeof(struct sctp_addip_param) +
3245 				     sizeof(**errp))
3246 				return false;
3247 			break;
3248 		case SCTP_PARAM_SUCCESS_REPORT:
3249 		case SCTP_PARAM_ADAPTATION_LAYER_IND:
3250 			if (length != sizeof(struct sctp_addip_param))
3251 				return false;
3252 			break;
3253 		default:
3254 			/* This is unknown to us, reject! */
3255 			return false;
3256 		}
3257 	}
3258 
3259 	/* Remaining sanity checks. */
3260 	if (addr_param_needed && !addr_param_seen)
3261 		return false;
3262 	if (!addr_param_needed && addr_param_seen)
3263 		return false;
3264 	if (param.v != chunk->chunk_end)
3265 		return false;
3266 
3267 	return true;
3268 }
3269 
3270 /* Process an incoming ASCONF chunk with the next expected serial no. and
3271  * return an ASCONF_ACK chunk to be sent in response.
3272  */
sctp_process_asconf(struct sctp_association * asoc,struct sctp_chunk * asconf)3273 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
3274 				       struct sctp_chunk *asconf)
3275 {
3276 	union sctp_addr_param *addr_param;
3277 	struct sctp_addip_chunk *addip;
3278 	struct sctp_chunk *asconf_ack;
3279 	bool all_param_pass = true;
3280 	struct sctp_addiphdr *hdr;
3281 	int length = 0, chunk_len;
3282 	union sctp_params param;
3283 	__be16 err_code;
3284 	__u32 serial;
3285 
3286 	addip = (struct sctp_addip_chunk *)asconf->chunk_hdr;
3287 	chunk_len = ntohs(asconf->chunk_hdr->length) -
3288 		    sizeof(struct sctp_chunkhdr);
3289 	hdr = (struct sctp_addiphdr *)asconf->skb->data;
3290 	serial = ntohl(hdr->serial);
3291 
3292 	/* Skip the addiphdr and store a pointer to address parameter.  */
3293 	length = sizeof(*hdr);
3294 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3295 	chunk_len -= length;
3296 
3297 	/* Skip the address parameter and store a pointer to the first
3298 	 * asconf parameter.
3299 	 */
3300 	length = ntohs(addr_param->p.length);
3301 	chunk_len -= length;
3302 
3303 	/* create an ASCONF_ACK chunk.
3304 	 * Based on the definitions of parameters, we know that the size of
3305 	 * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
3306 	 * parameters.
3307 	 */
3308 	asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
3309 	if (!asconf_ack)
3310 		goto done;
3311 
3312 	/* Process the TLVs contained within the ASCONF chunk. */
3313 	sctp_walk_params(param, addip, addip_hdr.params) {
3314 		/* Skip preceeding address parameters. */
3315 		if (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
3316 		    param.p->type == SCTP_PARAM_IPV6_ADDRESS)
3317 			continue;
3318 
3319 		err_code = sctp_process_asconf_param(asoc, asconf,
3320 						     param.addip);
3321 		/* ADDIP 4.1 A7)
3322 		 * If an error response is received for a TLV parameter,
3323 		 * all TLVs with no response before the failed TLV are
3324 		 * considered successful if not reported.  All TLVs after
3325 		 * the failed response are considered unsuccessful unless
3326 		 * a specific success indication is present for the parameter.
3327 		 */
3328 		if (err_code != SCTP_ERROR_NO_ERROR)
3329 			all_param_pass = false;
3330 		if (!all_param_pass)
3331 			sctp_add_asconf_response(asconf_ack, param.addip->crr_id,
3332 						 err_code, param.addip);
3333 
3334 		/* ADDIP 4.3 D11) When an endpoint receiving an ASCONF to add
3335 		 * an IP address sends an 'Out of Resource' in its response, it
3336 		 * MUST also fail any subsequent add or delete requests bundled
3337 		 * in the ASCONF.
3338 		 */
3339 		if (err_code == SCTP_ERROR_RSRC_LOW)
3340 			goto done;
3341 	}
3342 done:
3343 	asoc->peer.addip_serial++;
3344 
3345 	/* If we are sending a new ASCONF_ACK hold a reference to it in assoc
3346 	 * after freeing the reference to old asconf ack if any.
3347 	 */
3348 	if (asconf_ack) {
3349 		sctp_chunk_hold(asconf_ack);
3350 		list_add_tail(&asconf_ack->transmitted_list,
3351 			      &asoc->asconf_ack_list);
3352 	}
3353 
3354 	return asconf_ack;
3355 }
3356 
3357 /* Process a asconf parameter that is successfully acked. */
sctp_asconf_param_success(struct sctp_association * asoc,struct sctp_addip_param * asconf_param)3358 static void sctp_asconf_param_success(struct sctp_association *asoc,
3359 				      struct sctp_addip_param *asconf_param)
3360 {
3361 	struct sctp_bind_addr *bp = &asoc->base.bind_addr;
3362 	union sctp_addr_param *addr_param;
3363 	struct sctp_sockaddr_entry *saddr;
3364 	struct sctp_transport *transport;
3365 	union sctp_addr	addr;
3366 	struct sctp_af *af;
3367 
3368 	addr_param = (void *)asconf_param + sizeof(*asconf_param);
3369 
3370 	/* We have checked the packet before, so we do not check again.	*/
3371 	af = sctp_get_af_specific(param_type2af(addr_param->p.type));
3372 	if (!af->from_addr_param(&addr, addr_param, htons(bp->port), 0))
3373 		return;
3374 
3375 	switch (asconf_param->param_hdr.type) {
3376 	case SCTP_PARAM_ADD_IP:
3377 		/* This is always done in BH context with a socket lock
3378 		 * held, so the list can not change.
3379 		 */
3380 		local_bh_disable();
3381 		list_for_each_entry(saddr, &bp->address_list, list) {
3382 			if (sctp_cmp_addr_exact(&saddr->a, &addr))
3383 				saddr->state = SCTP_ADDR_SRC;
3384 		}
3385 		local_bh_enable();
3386 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3387 				transports) {
3388 			sctp_transport_dst_release(transport);
3389 		}
3390 		break;
3391 	case SCTP_PARAM_DEL_IP:
3392 		local_bh_disable();
3393 		sctp_del_bind_addr(bp, &addr);
3394 		if (asoc->asconf_addr_del_pending != NULL &&
3395 		    sctp_cmp_addr_exact(asoc->asconf_addr_del_pending, &addr)) {
3396 			kfree(asoc->asconf_addr_del_pending);
3397 			asoc->asconf_addr_del_pending = NULL;
3398 		}
3399 		local_bh_enable();
3400 		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
3401 				transports) {
3402 			sctp_transport_dst_release(transport);
3403 		}
3404 		break;
3405 	default:
3406 		break;
3407 	}
3408 }
3409 
3410 /* Get the corresponding ASCONF response error code from the ASCONF_ACK chunk
3411  * for the given asconf parameter.  If there is no response for this parameter,
3412  * return the error code based on the third argument 'no_err'.
3413  * ADDIP 4.1
3414  * A7) If an error response is received for a TLV parameter, all TLVs with no
3415  * response before the failed TLV are considered successful if not reported.
3416  * All TLVs after the failed response are considered unsuccessful unless a
3417  * specific success indication is present for the parameter.
3418  */
sctp_get_asconf_response(struct sctp_chunk * asconf_ack,struct sctp_addip_param * asconf_param,int no_err)3419 static __be16 sctp_get_asconf_response(struct sctp_chunk *asconf_ack,
3420 				       struct sctp_addip_param *asconf_param,
3421 				       int no_err)
3422 {
3423 	struct sctp_addip_param	*asconf_ack_param;
3424 	struct sctp_errhdr *err_param;
3425 	int asconf_ack_len;
3426 	__be16 err_code;
3427 	int length;
3428 
3429 	if (no_err)
3430 		err_code = SCTP_ERROR_NO_ERROR;
3431 	else
3432 		err_code = SCTP_ERROR_REQ_REFUSED;
3433 
3434 	asconf_ack_len = ntohs(asconf_ack->chunk_hdr->length) -
3435 			 sizeof(struct sctp_chunkhdr);
3436 
3437 	/* Skip the addiphdr from the asconf_ack chunk and store a pointer to
3438 	 * the first asconf_ack parameter.
3439 	 */
3440 	length = sizeof(struct sctp_addiphdr);
3441 	asconf_ack_param = (struct sctp_addip_param *)(asconf_ack->skb->data +
3442 						       length);
3443 	asconf_ack_len -= length;
3444 
3445 	while (asconf_ack_len > 0) {
3446 		if (asconf_ack_param->crr_id == asconf_param->crr_id) {
3447 			switch (asconf_ack_param->param_hdr.type) {
3448 			case SCTP_PARAM_SUCCESS_REPORT:
3449 				return SCTP_ERROR_NO_ERROR;
3450 			case SCTP_PARAM_ERR_CAUSE:
3451 				length = sizeof(*asconf_ack_param);
3452 				err_param = (void *)asconf_ack_param + length;
3453 				asconf_ack_len -= length;
3454 				if (asconf_ack_len > 0)
3455 					return err_param->cause;
3456 				else
3457 					return SCTP_ERROR_INV_PARAM;
3458 				break;
3459 			default:
3460 				return SCTP_ERROR_INV_PARAM;
3461 			}
3462 		}
3463 
3464 		length = ntohs(asconf_ack_param->param_hdr.length);
3465 		asconf_ack_param = (void *)asconf_ack_param + length;
3466 		asconf_ack_len -= length;
3467 	}
3468 
3469 	return err_code;
3470 }
3471 
3472 /* Process an incoming ASCONF_ACK chunk against the cached last ASCONF chunk. */
sctp_process_asconf_ack(struct sctp_association * asoc,struct sctp_chunk * asconf_ack)3473 int sctp_process_asconf_ack(struct sctp_association *asoc,
3474 			    struct sctp_chunk *asconf_ack)
3475 {
3476 	struct sctp_chunk *asconf = asoc->addip_last_asconf;
3477 	struct sctp_addip_param *asconf_param;
3478 	__be16 err_code = SCTP_ERROR_NO_ERROR;
3479 	union sctp_addr_param *addr_param;
3480 	int asconf_len = asconf->skb->len;
3481 	int all_param_pass = 0;
3482 	int length = 0;
3483 	int no_err = 1;
3484 	int retval = 0;
3485 
3486 	/* Skip the chunkhdr and addiphdr from the last asconf sent and store
3487 	 * a pointer to address parameter.
3488 	 */
3489 	length = sizeof(struct sctp_addip_chunk);
3490 	addr_param = (union sctp_addr_param *)(asconf->skb->data + length);
3491 	asconf_len -= length;
3492 
3493 	/* Skip the address parameter in the last asconf sent and store a
3494 	 * pointer to the first asconf parameter.
3495 	 */
3496 	length = ntohs(addr_param->p.length);
3497 	asconf_param = (void *)addr_param + length;
3498 	asconf_len -= length;
3499 
3500 	/* ADDIP 4.1
3501 	 * A8) If there is no response(s) to specific TLV parameter(s), and no
3502 	 * failures are indicated, then all request(s) are considered
3503 	 * successful.
3504 	 */
3505 	if (asconf_ack->skb->len == sizeof(struct sctp_addiphdr))
3506 		all_param_pass = 1;
3507 
3508 	/* Process the TLVs contained in the last sent ASCONF chunk. */
3509 	while (asconf_len > 0) {
3510 		if (all_param_pass)
3511 			err_code = SCTP_ERROR_NO_ERROR;
3512 		else {
3513 			err_code = sctp_get_asconf_response(asconf_ack,
3514 							    asconf_param,
3515 							    no_err);
3516 			if (no_err && (SCTP_ERROR_NO_ERROR != err_code))
3517 				no_err = 0;
3518 		}
3519 
3520 		switch (err_code) {
3521 		case SCTP_ERROR_NO_ERROR:
3522 			sctp_asconf_param_success(asoc, asconf_param);
3523 			break;
3524 
3525 		case SCTP_ERROR_RSRC_LOW:
3526 			retval = 1;
3527 			break;
3528 
3529 		case SCTP_ERROR_UNKNOWN_PARAM:
3530 			/* Disable sending this type of asconf parameter in
3531 			 * future.
3532 			 */
3533 			asoc->peer.addip_disabled_mask |=
3534 				asconf_param->param_hdr.type;
3535 			break;
3536 
3537 		case SCTP_ERROR_REQ_REFUSED:
3538 		case SCTP_ERROR_DEL_LAST_IP:
3539 		case SCTP_ERROR_DEL_SRC_IP:
3540 		default:
3541 			 break;
3542 		}
3543 
3544 		/* Skip the processed asconf parameter and move to the next
3545 		 * one.
3546 		 */
3547 		length = ntohs(asconf_param->param_hdr.length);
3548 		asconf_param = (void *)asconf_param + length;
3549 		asconf_len -= length;
3550 	}
3551 
3552 	if (no_err && asoc->src_out_of_asoc_ok) {
3553 		asoc->src_out_of_asoc_ok = 0;
3554 		sctp_transport_immediate_rtx(asoc->peer.primary_path);
3555 	}
3556 
3557 	/* Free the cached last sent asconf chunk. */
3558 	list_del_init(&asconf->transmitted_list);
3559 	sctp_chunk_free(asconf);
3560 	asoc->addip_last_asconf = NULL;
3561 
3562 	return retval;
3563 }
3564 
3565 /* Make a FWD TSN chunk. */
sctp_make_fwdtsn(const struct sctp_association * asoc,__u32 new_cum_tsn,size_t nstreams,struct sctp_fwdtsn_skip * skiplist)3566 struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
3567 				    __u32 new_cum_tsn, size_t nstreams,
3568 				    struct sctp_fwdtsn_skip *skiplist)
3569 {
3570 	struct sctp_chunk *retval = NULL;
3571 	struct sctp_fwdtsn_hdr ftsn_hdr;
3572 	struct sctp_fwdtsn_skip skip;
3573 	size_t hint;
3574 	int i;
3575 
3576 	hint = (nstreams + 1) * sizeof(__u32);
3577 
3578 	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
3579 
3580 	if (!retval)
3581 		return NULL;
3582 
3583 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3584 	retval->subh.fwdtsn_hdr =
3585 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3586 
3587 	for (i = 0; i < nstreams; i++) {
3588 		skip.stream = skiplist[i].stream;
3589 		skip.ssn = skiplist[i].ssn;
3590 		sctp_addto_chunk(retval, sizeof(skip), &skip);
3591 	}
3592 
3593 	return retval;
3594 }
3595 
sctp_make_ifwdtsn(const struct sctp_association * asoc,__u32 new_cum_tsn,size_t nstreams,struct sctp_ifwdtsn_skip * skiplist)3596 struct sctp_chunk *sctp_make_ifwdtsn(const struct sctp_association *asoc,
3597 				     __u32 new_cum_tsn, size_t nstreams,
3598 				     struct sctp_ifwdtsn_skip *skiplist)
3599 {
3600 	struct sctp_chunk *retval = NULL;
3601 	struct sctp_ifwdtsn_hdr ftsn_hdr;
3602 	size_t hint;
3603 
3604 	hint = (nstreams + 1) * sizeof(__u32);
3605 
3606 	retval = sctp_make_control(asoc, SCTP_CID_I_FWD_TSN, 0, hint,
3607 				   GFP_ATOMIC);
3608 	if (!retval)
3609 		return NULL;
3610 
3611 	ftsn_hdr.new_cum_tsn = htonl(new_cum_tsn);
3612 	retval->subh.ifwdtsn_hdr =
3613 		sctp_addto_chunk(retval, sizeof(ftsn_hdr), &ftsn_hdr);
3614 
3615 	sctp_addto_chunk(retval, nstreams * sizeof(skiplist[0]), skiplist);
3616 
3617 	return retval;
3618 }
3619 
3620 /* RE-CONFIG 3.1 (RE-CONFIG chunk)
3621  *   0                   1                   2                   3
3622  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3623  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3624  *  | Type = 130    |  Chunk Flags  |      Chunk Length             |
3625  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3626  *  \                                                               \
3627  *  /                  Re-configuration Parameter                   /
3628  *  \                                                               \
3629  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3630  *  \                                                               \
3631  *  /             Re-configuration Parameter (optional)             /
3632  *  \                                                               \
3633  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3634  */
sctp_make_reconf(const struct sctp_association * asoc,int length)3635 static struct sctp_chunk *sctp_make_reconf(const struct sctp_association *asoc,
3636 					   int length)
3637 {
3638 	struct sctp_reconf_chunk *reconf;
3639 	struct sctp_chunk *retval;
3640 
3641 	retval = sctp_make_control(asoc, SCTP_CID_RECONF, 0, length,
3642 				   GFP_ATOMIC);
3643 	if (!retval)
3644 		return NULL;
3645 
3646 	reconf = (struct sctp_reconf_chunk *)retval->chunk_hdr;
3647 	retval->param_hdr.v = reconf->params;
3648 
3649 	return retval;
3650 }
3651 
3652 /* RE-CONFIG 4.1 (STREAM OUT RESET)
3653  *   0                   1                   2                   3
3654  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3655  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3656  *  |     Parameter Type = 13       | Parameter Length = 16 + 2 * N |
3657  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3658  *  |           Re-configuration Request Sequence Number            |
3659  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3660  *  |           Re-configuration Response Sequence Number           |
3661  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3662  *  |                Sender's Last Assigned TSN                     |
3663  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3664  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3665  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3666  *  /                            ......                             /
3667  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3668  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3669  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3670  *
3671  * RE-CONFIG 4.2 (STREAM IN RESET)
3672  *   0                   1                   2                   3
3673  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3674  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3675  *  |     Parameter Type = 14       |  Parameter Length = 8 + 2 * N |
3676  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3677  *  |          Re-configuration Request Sequence Number             |
3678  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3679  *  |  Stream Number 1 (optional)   |    Stream Number 2 (optional) |
3680  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3681  *  /                            ......                             /
3682  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3683  *  |  Stream Number N-1 (optional) |    Stream Number N (optional) |
3684  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3685  */
sctp_make_strreset_req(const struct sctp_association * asoc,__u16 stream_num,__be16 * stream_list,bool out,bool in)3686 struct sctp_chunk *sctp_make_strreset_req(
3687 					const struct sctp_association *asoc,
3688 					__u16 stream_num, __be16 *stream_list,
3689 					bool out, bool in)
3690 {
3691 	__u16 stream_len = stream_num * sizeof(__u16);
3692 	struct sctp_strreset_outreq outreq;
3693 	struct sctp_strreset_inreq inreq;
3694 	struct sctp_chunk *retval;
3695 	__u16 outlen, inlen;
3696 
3697 	outlen = (sizeof(outreq) + stream_len) * out;
3698 	inlen = (sizeof(inreq) + stream_len) * in;
3699 
3700 	retval = sctp_make_reconf(asoc, SCTP_PAD4(outlen) + SCTP_PAD4(inlen));
3701 	if (!retval)
3702 		return NULL;
3703 
3704 	if (outlen) {
3705 		outreq.param_hdr.type = SCTP_PARAM_RESET_OUT_REQUEST;
3706 		outreq.param_hdr.length = htons(outlen);
3707 		outreq.request_seq = htonl(asoc->strreset_outseq);
3708 		outreq.response_seq = htonl(asoc->strreset_inseq - 1);
3709 		outreq.send_reset_at_tsn = htonl(asoc->next_tsn - 1);
3710 
3711 		sctp_addto_chunk(retval, sizeof(outreq), &outreq);
3712 
3713 		if (stream_len)
3714 			sctp_addto_chunk(retval, stream_len, stream_list);
3715 	}
3716 
3717 	if (inlen) {
3718 		inreq.param_hdr.type = SCTP_PARAM_RESET_IN_REQUEST;
3719 		inreq.param_hdr.length = htons(inlen);
3720 		inreq.request_seq = htonl(asoc->strreset_outseq + out);
3721 
3722 		sctp_addto_chunk(retval, sizeof(inreq), &inreq);
3723 
3724 		if (stream_len)
3725 			sctp_addto_chunk(retval, stream_len, stream_list);
3726 	}
3727 
3728 	return retval;
3729 }
3730 
3731 /* RE-CONFIG 4.3 (SSN/TSN RESET ALL)
3732  *   0                   1                   2                   3
3733  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3734  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3735  *  |     Parameter Type = 15       |      Parameter Length = 8     |
3736  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3737  *  |         Re-configuration Request Sequence Number              |
3738  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3739  */
sctp_make_strreset_tsnreq(const struct sctp_association * asoc)3740 struct sctp_chunk *sctp_make_strreset_tsnreq(
3741 					const struct sctp_association *asoc)
3742 {
3743 	struct sctp_strreset_tsnreq tsnreq;
3744 	__u16 length = sizeof(tsnreq);
3745 	struct sctp_chunk *retval;
3746 
3747 	retval = sctp_make_reconf(asoc, length);
3748 	if (!retval)
3749 		return NULL;
3750 
3751 	tsnreq.param_hdr.type = SCTP_PARAM_RESET_TSN_REQUEST;
3752 	tsnreq.param_hdr.length = htons(length);
3753 	tsnreq.request_seq = htonl(asoc->strreset_outseq);
3754 
3755 	sctp_addto_chunk(retval, sizeof(tsnreq), &tsnreq);
3756 
3757 	return retval;
3758 }
3759 
3760 /* RE-CONFIG 4.5/4.6 (ADD STREAM)
3761  *   0                   1                   2                   3
3762  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3763  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3764  *  |     Parameter Type = 17       |      Parameter Length = 12    |
3765  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3766  *  |          Re-configuration Request Sequence Number             |
3767  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3768  *  |      Number of new streams    |         Reserved              |
3769  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3770  */
sctp_make_strreset_addstrm(const struct sctp_association * asoc,__u16 out,__u16 in)3771 struct sctp_chunk *sctp_make_strreset_addstrm(
3772 					const struct sctp_association *asoc,
3773 					__u16 out, __u16 in)
3774 {
3775 	struct sctp_strreset_addstrm addstrm;
3776 	__u16 size = sizeof(addstrm);
3777 	struct sctp_chunk *retval;
3778 
3779 	retval = sctp_make_reconf(asoc, (!!out + !!in) * size);
3780 	if (!retval)
3781 		return NULL;
3782 
3783 	if (out) {
3784 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_OUT_STREAMS;
3785 		addstrm.param_hdr.length = htons(size);
3786 		addstrm.number_of_streams = htons(out);
3787 		addstrm.request_seq = htonl(asoc->strreset_outseq);
3788 		addstrm.reserved = 0;
3789 
3790 		sctp_addto_chunk(retval, size, &addstrm);
3791 	}
3792 
3793 	if (in) {
3794 		addstrm.param_hdr.type = SCTP_PARAM_RESET_ADD_IN_STREAMS;
3795 		addstrm.param_hdr.length = htons(size);
3796 		addstrm.number_of_streams = htons(in);
3797 		addstrm.request_seq = htonl(asoc->strreset_outseq + !!out);
3798 		addstrm.reserved = 0;
3799 
3800 		sctp_addto_chunk(retval, size, &addstrm);
3801 	}
3802 
3803 	return retval;
3804 }
3805 
3806 /* RE-CONFIG 4.4 (RESP)
3807  *   0                   1                   2                   3
3808  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3809  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3810  *  |     Parameter Type = 16       |      Parameter Length         |
3811  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3812  *  |         Re-configuration Response Sequence Number             |
3813  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3814  *  |                            Result                             |
3815  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3816  */
sctp_make_strreset_resp(const struct sctp_association * asoc,__u32 result,__u32 sn)3817 struct sctp_chunk *sctp_make_strreset_resp(const struct sctp_association *asoc,
3818 					   __u32 result, __u32 sn)
3819 {
3820 	struct sctp_strreset_resp resp;
3821 	__u16 length = sizeof(resp);
3822 	struct sctp_chunk *retval;
3823 
3824 	retval = sctp_make_reconf(asoc, length);
3825 	if (!retval)
3826 		return NULL;
3827 
3828 	resp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3829 	resp.param_hdr.length = htons(length);
3830 	resp.response_seq = htonl(sn);
3831 	resp.result = htonl(result);
3832 
3833 	sctp_addto_chunk(retval, sizeof(resp), &resp);
3834 
3835 	return retval;
3836 }
3837 
3838 /* RE-CONFIG 4.4 OPTIONAL (TSNRESP)
3839  *   0                   1                   2                   3
3840  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
3841  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3842  *  |     Parameter Type = 16       |      Parameter Length         |
3843  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3844  *  |         Re-configuration Response Sequence Number             |
3845  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3846  *  |                            Result                             |
3847  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3848  *  |                   Sender's Next TSN (optional)                |
3849  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3850  *  |                  Receiver's Next TSN (optional)               |
3851  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3852  */
sctp_make_strreset_tsnresp(struct sctp_association * asoc,__u32 result,__u32 sn,__u32 sender_tsn,__u32 receiver_tsn)3853 struct sctp_chunk *sctp_make_strreset_tsnresp(struct sctp_association *asoc,
3854 					      __u32 result, __u32 sn,
3855 					      __u32 sender_tsn,
3856 					      __u32 receiver_tsn)
3857 {
3858 	struct sctp_strreset_resptsn tsnresp;
3859 	__u16 length = sizeof(tsnresp);
3860 	struct sctp_chunk *retval;
3861 
3862 	retval = sctp_make_reconf(asoc, length);
3863 	if (!retval)
3864 		return NULL;
3865 
3866 	tsnresp.param_hdr.type = SCTP_PARAM_RESET_RESPONSE;
3867 	tsnresp.param_hdr.length = htons(length);
3868 
3869 	tsnresp.response_seq = htonl(sn);
3870 	tsnresp.result = htonl(result);
3871 	tsnresp.senders_next_tsn = htonl(sender_tsn);
3872 	tsnresp.receivers_next_tsn = htonl(receiver_tsn);
3873 
3874 	sctp_addto_chunk(retval, sizeof(tsnresp), &tsnresp);
3875 
3876 	return retval;
3877 }
3878 
sctp_verify_reconf(const struct sctp_association * asoc,struct sctp_chunk * chunk,struct sctp_paramhdr ** errp)3879 bool sctp_verify_reconf(const struct sctp_association *asoc,
3880 			struct sctp_chunk *chunk,
3881 			struct sctp_paramhdr **errp)
3882 {
3883 	struct sctp_reconf_chunk *hdr;
3884 	union sctp_params param;
3885 	__be16 last = 0;
3886 	__u16 cnt = 0;
3887 
3888 	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
3889 	sctp_walk_params(param, hdr, params) {
3890 		__u16 length = ntohs(param.p->length);
3891 
3892 		*errp = param.p;
3893 		if (cnt++ > 2)
3894 			return false;
3895 		switch (param.p->type) {
3896 		case SCTP_PARAM_RESET_OUT_REQUEST:
3897 			if (length < sizeof(struct sctp_strreset_outreq) ||
3898 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3899 			     last != SCTP_PARAM_RESET_IN_REQUEST))
3900 				return false;
3901 			break;
3902 		case SCTP_PARAM_RESET_IN_REQUEST:
3903 			if (length < sizeof(struct sctp_strreset_inreq) ||
3904 			    (last && last != SCTP_PARAM_RESET_OUT_REQUEST))
3905 				return false;
3906 			break;
3907 		case SCTP_PARAM_RESET_RESPONSE:
3908 			if ((length != sizeof(struct sctp_strreset_resp) &&
3909 			     length != sizeof(struct sctp_strreset_resptsn)) ||
3910 			    (last && last != SCTP_PARAM_RESET_RESPONSE &&
3911 			     last != SCTP_PARAM_RESET_OUT_REQUEST))
3912 				return false;
3913 			break;
3914 		case SCTP_PARAM_RESET_TSN_REQUEST:
3915 			if (length !=
3916 			    sizeof(struct sctp_strreset_tsnreq) || last)
3917 				return false;
3918 			break;
3919 		case SCTP_PARAM_RESET_ADD_IN_STREAMS:
3920 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3921 			    (last && last != SCTP_PARAM_RESET_ADD_OUT_STREAMS))
3922 				return false;
3923 			break;
3924 		case SCTP_PARAM_RESET_ADD_OUT_STREAMS:
3925 			if (length != sizeof(struct sctp_strreset_addstrm) ||
3926 			    (last && last != SCTP_PARAM_RESET_ADD_IN_STREAMS))
3927 				return false;
3928 			break;
3929 		default:
3930 			return false;
3931 		}
3932 
3933 		last = param.p->type;
3934 	}
3935 
3936 	return true;
3937 }
3938