1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2003
4  * Copyright (c) Cisco 1999,2000
5  * Copyright (c) Motorola 1999,2000,2001
6  * Copyright (c) La Monte H.P. Yarroll 2001
7  *
8  * This file is part of the SCTP kernel implementation.
9  *
10  * A collection class to handle the storage of transport addresses.
11  *
12  * Please send any bug reports or fixes you make to the
13  * email address(es):
14  *    lksctp developers <linux-sctp@vger.kernel.org>
15  *
16  * Written or modified by:
17  *    La Monte H.P. Yarroll <piggy@acm.org>
18  *    Karl Knutson          <karl@athena.chicago.il.us>
19  *    Jon Grimm             <jgrimm@us.ibm.com>
20  *    Daisy Chang           <daisyc@us.ibm.com>
21  */
22 
23 #include <linux/types.h>
24 #include <linux/slab.h>
25 #include <linux/in.h>
26 #include <net/sock.h>
27 #include <net/ipv6.h>
28 #include <net/if_inet6.h>
29 #include <net/sctp/sctp.h>
30 #include <net/sctp/sm.h>
31 
32 /* Forward declarations for internal helpers. */
33 static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
34 			      union sctp_addr *addr, enum sctp_scope scope,
35 			      gfp_t gfp, int flags);
36 static void sctp_bind_addr_clean(struct sctp_bind_addr *);
37 
38 /* First Level Abstractions. */
39 
40 /* Copy 'src' to 'dest' taking 'scope' into account.  Omit addresses
41  * in 'src' which have a broader scope than 'scope'.
42  */
sctp_bind_addr_copy(struct net * net,struct sctp_bind_addr * dest,const struct sctp_bind_addr * src,enum sctp_scope scope,gfp_t gfp,int flags)43 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
44 			const struct sctp_bind_addr *src,
45 			enum sctp_scope scope, gfp_t gfp,
46 			int flags)
47 {
48 	struct sctp_sockaddr_entry *addr;
49 	int error = 0;
50 
51 	/* All addresses share the same port.  */
52 	dest->port = src->port;
53 
54 	/* Extract the addresses which are relevant for this scope.  */
55 	list_for_each_entry(addr, &src->address_list, list) {
56 		error = sctp_copy_one_addr(net, dest, &addr->a, scope,
57 					   gfp, flags);
58 		if (error < 0)
59 			goto out;
60 	}
61 
62 	/* If there are no addresses matching the scope and
63 	 * this is global scope, try to get a link scope address, with
64 	 * the assumption that we must be sitting behind a NAT.
65 	 */
66 	if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {
67 		list_for_each_entry(addr, &src->address_list, list) {
68 			error = sctp_copy_one_addr(net, dest, &addr->a,
69 						   SCTP_SCOPE_LINK, gfp,
70 						   flags);
71 			if (error < 0)
72 				goto out;
73 		}
74 	}
75 
76 out:
77 	if (error)
78 		sctp_bind_addr_clean(dest);
79 
80 	return error;
81 }
82 
83 /* Exactly duplicate the address lists.  This is necessary when doing
84  * peer-offs and accepts.  We don't want to put all the current system
85  * addresses into the endpoint.  That's useless.  But we do want duplicat
86  * the list of bound addresses that the older endpoint used.
87  */
sctp_bind_addr_dup(struct sctp_bind_addr * dest,const struct sctp_bind_addr * src,gfp_t gfp)88 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
89 			const struct sctp_bind_addr *src,
90 			gfp_t gfp)
91 {
92 	struct sctp_sockaddr_entry *addr;
93 	int error = 0;
94 
95 	/* All addresses share the same port.  */
96 	dest->port = src->port;
97 
98 	list_for_each_entry(addr, &src->address_list, list) {
99 		error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
100 					   1, gfp);
101 		if (error < 0)
102 			break;
103 	}
104 
105 	return error;
106 }
107 
108 /* Initialize the SCTP_bind_addr structure for either an endpoint or
109  * an association.
110  */
sctp_bind_addr_init(struct sctp_bind_addr * bp,__u16 port)111 void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
112 {
113 	INIT_LIST_HEAD(&bp->address_list);
114 	bp->port = port;
115 }
116 
117 /* Dispose of the address list. */
sctp_bind_addr_clean(struct sctp_bind_addr * bp)118 static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
119 {
120 	struct sctp_sockaddr_entry *addr, *temp;
121 
122 	/* Empty the bind address list. */
123 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
124 		list_del_rcu(&addr->list);
125 		kfree_rcu(addr, rcu);
126 		SCTP_DBG_OBJCNT_DEC(addr);
127 	}
128 }
129 
130 /* Dispose of an SCTP_bind_addr structure  */
sctp_bind_addr_free(struct sctp_bind_addr * bp)131 void sctp_bind_addr_free(struct sctp_bind_addr *bp)
132 {
133 	/* Empty the bind address list. */
134 	sctp_bind_addr_clean(bp);
135 }
136 
137 /* Add an address to the bind address list in the SCTP_bind_addr structure. */
sctp_add_bind_addr(struct sctp_bind_addr * bp,union sctp_addr * new,int new_size,__u8 addr_state,gfp_t gfp)138 int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
139 		       int new_size, __u8 addr_state, gfp_t gfp)
140 {
141 	struct sctp_sockaddr_entry *addr;
142 
143 	/* Add the address to the bind address list.  */
144 	addr = kzalloc(sizeof(*addr), gfp);
145 	if (!addr)
146 		return -ENOMEM;
147 
148 	memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));
149 
150 	/* Fix up the port if it has not yet been set.
151 	 * Both v4 and v6 have the port at the same offset.
152 	 */
153 	if (!addr->a.v4.sin_port)
154 		addr->a.v4.sin_port = htons(bp->port);
155 
156 	addr->state = addr_state;
157 	addr->valid = 1;
158 
159 	INIT_LIST_HEAD(&addr->list);
160 
161 	/* We always hold a socket lock when calling this function,
162 	 * and that acts as a writer synchronizing lock.
163 	 */
164 	list_add_tail_rcu(&addr->list, &bp->address_list);
165 	SCTP_DBG_OBJCNT_INC(addr);
166 
167 	return 0;
168 }
169 
170 /* Delete an address from the bind address list in the SCTP_bind_addr
171  * structure.
172  */
sctp_del_bind_addr(struct sctp_bind_addr * bp,union sctp_addr * del_addr)173 int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
174 {
175 	struct sctp_sockaddr_entry *addr, *temp;
176 	int found = 0;
177 
178 	/* We hold the socket lock when calling this function,
179 	 * and that acts as a writer synchronizing lock.
180 	 */
181 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
182 		if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
183 			/* Found the exact match. */
184 			found = 1;
185 			addr->valid = 0;
186 			list_del_rcu(&addr->list);
187 			break;
188 		}
189 	}
190 
191 	if (found) {
192 		kfree_rcu(addr, rcu);
193 		SCTP_DBG_OBJCNT_DEC(addr);
194 		return 0;
195 	}
196 
197 	return -EINVAL;
198 }
199 
200 /* Create a network byte-order representation of all the addresses
201  * formated as SCTP parameters.
202  *
203  * The second argument is the return value for the length.
204  */
sctp_bind_addrs_to_raw(const struct sctp_bind_addr * bp,int * addrs_len,gfp_t gfp)205 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
206 					 int *addrs_len,
207 					 gfp_t gfp)
208 {
209 	union sctp_params addrparms;
210 	union sctp_params retval;
211 	int addrparms_len;
212 	union sctp_addr_param rawaddr;
213 	int len;
214 	struct sctp_sockaddr_entry *addr;
215 	struct list_head *pos;
216 	struct sctp_af *af;
217 
218 	addrparms_len = 0;
219 	len = 0;
220 
221 	/* Allocate enough memory at once. */
222 	list_for_each(pos, &bp->address_list) {
223 		len += sizeof(union sctp_addr_param);
224 	}
225 
226 	/* Don't even bother embedding an address if there
227 	 * is only one.
228 	 */
229 	if (len == sizeof(union sctp_addr_param)) {
230 		retval.v = NULL;
231 		goto end_raw;
232 	}
233 
234 	retval.v = kmalloc(len, gfp);
235 	if (!retval.v)
236 		goto end_raw;
237 
238 	addrparms = retval;
239 
240 	list_for_each_entry(addr, &bp->address_list, list) {
241 		af = sctp_get_af_specific(addr->a.v4.sin_family);
242 		len = af->to_addr_param(&addr->a, &rawaddr);
243 		memcpy(addrparms.v, &rawaddr, len);
244 		addrparms.v += len;
245 		addrparms_len += len;
246 	}
247 
248 end_raw:
249 	*addrs_len = addrparms_len;
250 	return retval;
251 }
252 
253 /*
254  * Create an address list out of the raw address list format (IPv4 and IPv6
255  * address parameters).
256  */
sctp_raw_to_bind_addrs(struct sctp_bind_addr * bp,__u8 * raw_addr_list,int addrs_len,__u16 port,gfp_t gfp)257 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
258 			   int addrs_len, __u16 port, gfp_t gfp)
259 {
260 	union sctp_addr_param *rawaddr;
261 	struct sctp_paramhdr *param;
262 	union sctp_addr addr;
263 	int retval = 0;
264 	int len;
265 	struct sctp_af *af;
266 
267 	/* Convert the raw address to standard address format */
268 	while (addrs_len) {
269 		param = (struct sctp_paramhdr *)raw_addr_list;
270 		rawaddr = (union sctp_addr_param *)raw_addr_list;
271 
272 		af = sctp_get_af_specific(param_type2af(param->type));
273 		if (unlikely(!af) ||
274 		    !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
275 			retval = -EINVAL;
276 			goto out_err;
277 		}
278 
279 		if (sctp_bind_addr_state(bp, &addr) != -1)
280 			goto next;
281 		retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
282 					    SCTP_ADDR_SRC, gfp);
283 		if (retval)
284 			/* Can't finish building the list, clean up. */
285 			goto out_err;
286 
287 next:
288 		len = ntohs(param->length);
289 		addrs_len -= len;
290 		raw_addr_list += len;
291 	}
292 
293 	return retval;
294 
295 out_err:
296 	if (retval)
297 		sctp_bind_addr_clean(bp);
298 
299 	return retval;
300 }
301 
302 /********************************************************************
303  * 2nd Level Abstractions
304  ********************************************************************/
305 
306 /* Does this contain a specified address?  Allow wildcarding. */
sctp_bind_addr_match(struct sctp_bind_addr * bp,const union sctp_addr * addr,struct sctp_sock * opt)307 int sctp_bind_addr_match(struct sctp_bind_addr *bp,
308 			 const union sctp_addr *addr,
309 			 struct sctp_sock *opt)
310 {
311 	struct sctp_sockaddr_entry *laddr;
312 	int match = 0;
313 
314 	rcu_read_lock();
315 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
316 		if (!laddr->valid)
317 			continue;
318 		if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
319 			match = 1;
320 			break;
321 		}
322 	}
323 	rcu_read_unlock();
324 
325 	return match;
326 }
327 
sctp_bind_addrs_check(struct sctp_sock * sp,struct sctp_sock * sp2,int cnt2)328 int sctp_bind_addrs_check(struct sctp_sock *sp,
329 			  struct sctp_sock *sp2, int cnt2)
330 {
331 	struct sctp_bind_addr *bp2 = &sp2->ep->base.bind_addr;
332 	struct sctp_bind_addr *bp = &sp->ep->base.bind_addr;
333 	struct sctp_sockaddr_entry *laddr, *laddr2;
334 	bool exist = false;
335 	int cnt = 0;
336 
337 	rcu_read_lock();
338 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
339 		list_for_each_entry_rcu(laddr2, &bp2->address_list, list) {
340 			if (sp->pf->af->cmp_addr(&laddr->a, &laddr2->a) &&
341 			    laddr->valid && laddr2->valid) {
342 				exist = true;
343 				goto next;
344 			}
345 		}
346 		cnt = 0;
347 		break;
348 next:
349 		cnt++;
350 	}
351 	rcu_read_unlock();
352 
353 	return (cnt == cnt2) ? 0 : (exist ? -EEXIST : 1);
354 }
355 
356 /* Does the address 'addr' conflict with any addresses in
357  * the bp.
358  */
sctp_bind_addr_conflict(struct sctp_bind_addr * bp,const union sctp_addr * addr,struct sctp_sock * bp_sp,struct sctp_sock * addr_sp)359 int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
360 			    const union sctp_addr *addr,
361 			    struct sctp_sock *bp_sp,
362 			    struct sctp_sock *addr_sp)
363 {
364 	struct sctp_sockaddr_entry *laddr;
365 	int conflict = 0;
366 	struct sctp_sock *sp;
367 
368 	/* Pick the IPv6 socket as the basis of comparison
369 	 * since it's usually a superset of the IPv4.
370 	 * If there is no IPv6 socket, then default to bind_addr.
371 	 */
372 	if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
373 		sp = bp_sp;
374 	else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
375 		sp = addr_sp;
376 	else
377 		sp = bp_sp;
378 
379 	rcu_read_lock();
380 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
381 		if (!laddr->valid)
382 			continue;
383 
384 		conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
385 		if (conflict)
386 			break;
387 	}
388 	rcu_read_unlock();
389 
390 	return conflict;
391 }
392 
393 /* Get the state of the entry in the bind_addr_list */
sctp_bind_addr_state(const struct sctp_bind_addr * bp,const union sctp_addr * addr)394 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
395 			 const union sctp_addr *addr)
396 {
397 	struct sctp_sockaddr_entry *laddr;
398 	struct sctp_af *af;
399 
400 	af = sctp_get_af_specific(addr->sa.sa_family);
401 	if (unlikely(!af))
402 		return -1;
403 
404 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
405 		if (!laddr->valid)
406 			continue;
407 		if (af->cmp_addr(&laddr->a, addr))
408 			return laddr->state;
409 	}
410 
411 	return -1;
412 }
413 
414 /* Find the first address in the bind address list that is not present in
415  * the addrs packed array.
416  */
sctp_find_unmatch_addr(struct sctp_bind_addr * bp,const union sctp_addr * addrs,int addrcnt,struct sctp_sock * opt)417 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
418 					const union sctp_addr	*addrs,
419 					int			addrcnt,
420 					struct sctp_sock	*opt)
421 {
422 	struct sctp_sockaddr_entry	*laddr;
423 	union sctp_addr			*addr;
424 	void 				*addr_buf;
425 	struct sctp_af			*af;
426 	int				i;
427 
428 	/* This is only called sctp_send_asconf_del_ip() and we hold
429 	 * the socket lock in that code patch, so that address list
430 	 * can't change.
431 	 */
432 	list_for_each_entry(laddr, &bp->address_list, list) {
433 		addr_buf = (union sctp_addr *)addrs;
434 		for (i = 0; i < addrcnt; i++) {
435 			addr = addr_buf;
436 			af = sctp_get_af_specific(addr->v4.sin_family);
437 			if (!af)
438 				break;
439 
440 			if (opt->pf->cmp_addr(&laddr->a, addr, opt))
441 				break;
442 
443 			addr_buf += af->sockaddr_len;
444 		}
445 		if (i == addrcnt)
446 			return &laddr->a;
447 	}
448 
449 	return NULL;
450 }
451 
452 /* Copy out addresses from the global local address list. */
sctp_copy_one_addr(struct net * net,struct sctp_bind_addr * dest,union sctp_addr * addr,enum sctp_scope scope,gfp_t gfp,int flags)453 static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
454 			      union sctp_addr *addr, enum sctp_scope scope,
455 			      gfp_t gfp, int flags)
456 {
457 	int error = 0;
458 
459 	if (sctp_is_any(NULL, addr)) {
460 		error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);
461 	} else if (sctp_in_scope(net, addr, scope)) {
462 		/* Now that the address is in scope, check to see if
463 		 * the address type is supported by local sock as
464 		 * well as the remote peer.
465 		 */
466 		if ((((AF_INET == addr->sa.sa_family) &&
467 		      (flags & SCTP_ADDR4_ALLOWED) &&
468 		      (flags & SCTP_ADDR4_PEERSUPP))) ||
469 		    (((AF_INET6 == addr->sa.sa_family) &&
470 		      (flags & SCTP_ADDR6_ALLOWED) &&
471 		      (flags & SCTP_ADDR6_PEERSUPP))))
472 			error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
473 						   SCTP_ADDR_SRC, gfp);
474 	}
475 
476 	return error;
477 }
478 
479 /* Is this a wildcard address?  */
sctp_is_any(struct sock * sk,const union sctp_addr * addr)480 int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
481 {
482 	unsigned short fam = 0;
483 	struct sctp_af *af;
484 
485 	/* Try to get the right address family */
486 	if (addr->sa.sa_family != AF_UNSPEC)
487 		fam = addr->sa.sa_family;
488 	else if (sk)
489 		fam = sk->sk_family;
490 
491 	af = sctp_get_af_specific(fam);
492 	if (!af)
493 		return 0;
494 
495 	return af->is_any(addr);
496 }
497 
498 /* Is 'addr' valid for 'scope'?  */
sctp_in_scope(struct net * net,const union sctp_addr * addr,enum sctp_scope scope)499 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
500 		  enum sctp_scope scope)
501 {
502 	enum sctp_scope addr_scope = sctp_scope(addr);
503 
504 	/* The unusable SCTP addresses will not be considered with
505 	 * any defined scopes.
506 	 */
507 	if (SCTP_SCOPE_UNUSABLE == addr_scope)
508 		return 0;
509 	/*
510 	 * For INIT and INIT-ACK address list, let L be the level of
511 	 * requested destination address, sender and receiver
512 	 * SHOULD include all of its addresses with level greater
513 	 * than or equal to L.
514 	 *
515 	 * Address scoping can be selectively controlled via sysctl
516 	 * option
517 	 */
518 	switch (net->sctp.scope_policy) {
519 	case SCTP_SCOPE_POLICY_DISABLE:
520 		return 1;
521 	case SCTP_SCOPE_POLICY_ENABLE:
522 		if (addr_scope <= scope)
523 			return 1;
524 		break;
525 	case SCTP_SCOPE_POLICY_PRIVATE:
526 		if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
527 			return 1;
528 		break;
529 	case SCTP_SCOPE_POLICY_LINK:
530 		if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
531 			return 1;
532 		break;
533 	default:
534 		break;
535 	}
536 
537 	return 0;
538 }
539 
sctp_is_ep_boundall(struct sock * sk)540 int sctp_is_ep_boundall(struct sock *sk)
541 {
542 	struct sctp_bind_addr *bp;
543 	struct sctp_sockaddr_entry *addr;
544 
545 	bp = &sctp_sk(sk)->ep->base.bind_addr;
546 	if (sctp_list_single_entry(&bp->address_list)) {
547 		addr = list_entry(bp->address_list.next,
548 				  struct sctp_sockaddr_entry, list);
549 		if (sctp_is_any(sk, &addr->a))
550 			return 1;
551 	}
552 	return 0;
553 }
554 
555 /********************************************************************
556  * 3rd Level Abstractions
557  ********************************************************************/
558 
559 /* What is the scope of 'addr'?  */
sctp_scope(const union sctp_addr * addr)560 enum sctp_scope sctp_scope(const union sctp_addr *addr)
561 {
562 	struct sctp_af *af;
563 
564 	af = sctp_get_af_specific(addr->sa.sa_family);
565 	if (!af)
566 		return SCTP_SCOPE_UNUSABLE;
567 
568 	return af->scope((union sctp_addr *)addr);
569 }
570