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 	/* If somehow no addresses were found that can be used with this
77 	 * scope, it's an error.
78 	 */
79 	if (list_empty(&dest->address_list))
80 		error = -ENETUNREACH;
81 
82 out:
83 	if (error)
84 		sctp_bind_addr_clean(dest);
85 
86 	return error;
87 }
88 
89 /* Exactly duplicate the address lists.  This is necessary when doing
90  * peer-offs and accepts.  We don't want to put all the current system
91  * addresses into the endpoint.  That's useless.  But we do want duplicat
92  * the list of bound addresses that the older endpoint used.
93  */
sctp_bind_addr_dup(struct sctp_bind_addr * dest,const struct sctp_bind_addr * src,gfp_t gfp)94 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
95 			const struct sctp_bind_addr *src,
96 			gfp_t gfp)
97 {
98 	struct sctp_sockaddr_entry *addr;
99 	int error = 0;
100 
101 	/* All addresses share the same port.  */
102 	dest->port = src->port;
103 
104 	list_for_each_entry(addr, &src->address_list, list) {
105 		error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
106 					   1, gfp);
107 		if (error < 0)
108 			break;
109 	}
110 
111 	return error;
112 }
113 
114 /* Initialize the SCTP_bind_addr structure for either an endpoint or
115  * an association.
116  */
sctp_bind_addr_init(struct sctp_bind_addr * bp,__u16 port)117 void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
118 {
119 	INIT_LIST_HEAD(&bp->address_list);
120 	bp->port = port;
121 }
122 
123 /* Dispose of the address list. */
sctp_bind_addr_clean(struct sctp_bind_addr * bp)124 static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
125 {
126 	struct sctp_sockaddr_entry *addr, *temp;
127 
128 	/* Empty the bind address list. */
129 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
130 		list_del_rcu(&addr->list);
131 		kfree_rcu(addr, rcu);
132 		SCTP_DBG_OBJCNT_DEC(addr);
133 	}
134 }
135 
136 /* Dispose of an SCTP_bind_addr structure  */
sctp_bind_addr_free(struct sctp_bind_addr * bp)137 void sctp_bind_addr_free(struct sctp_bind_addr *bp)
138 {
139 	/* Empty the bind address list. */
140 	sctp_bind_addr_clean(bp);
141 }
142 
143 /* 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)144 int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
145 		       int new_size, __u8 addr_state, gfp_t gfp)
146 {
147 	struct sctp_sockaddr_entry *addr;
148 
149 	/* Add the address to the bind address list.  */
150 	addr = kzalloc(sizeof(*addr), gfp);
151 	if (!addr)
152 		return -ENOMEM;
153 
154 	memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));
155 
156 	/* Fix up the port if it has not yet been set.
157 	 * Both v4 and v6 have the port at the same offset.
158 	 */
159 	if (!addr->a.v4.sin_port)
160 		addr->a.v4.sin_port = htons(bp->port);
161 
162 	addr->state = addr_state;
163 	addr->valid = 1;
164 
165 	INIT_LIST_HEAD(&addr->list);
166 
167 	/* We always hold a socket lock when calling this function,
168 	 * and that acts as a writer synchronizing lock.
169 	 */
170 	list_add_tail_rcu(&addr->list, &bp->address_list);
171 	SCTP_DBG_OBJCNT_INC(addr);
172 
173 	return 0;
174 }
175 
176 /* Delete an address from the bind address list in the SCTP_bind_addr
177  * structure.
178  */
sctp_del_bind_addr(struct sctp_bind_addr * bp,union sctp_addr * del_addr)179 int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
180 {
181 	struct sctp_sockaddr_entry *addr, *temp;
182 	int found = 0;
183 
184 	/* We hold the socket lock when calling this function,
185 	 * and that acts as a writer synchronizing lock.
186 	 */
187 	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
188 		if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
189 			/* Found the exact match. */
190 			found = 1;
191 			addr->valid = 0;
192 			list_del_rcu(&addr->list);
193 			break;
194 		}
195 	}
196 
197 	if (found) {
198 		kfree_rcu(addr, rcu);
199 		SCTP_DBG_OBJCNT_DEC(addr);
200 		return 0;
201 	}
202 
203 	return -EINVAL;
204 }
205 
206 /* Create a network byte-order representation of all the addresses
207  * formated as SCTP parameters.
208  *
209  * The second argument is the return value for the length.
210  */
sctp_bind_addrs_to_raw(const struct sctp_bind_addr * bp,int * addrs_len,gfp_t gfp)211 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
212 					 int *addrs_len,
213 					 gfp_t gfp)
214 {
215 	union sctp_params addrparms;
216 	union sctp_params retval;
217 	int addrparms_len;
218 	union sctp_addr_param rawaddr;
219 	int len;
220 	struct sctp_sockaddr_entry *addr;
221 	struct list_head *pos;
222 	struct sctp_af *af;
223 
224 	addrparms_len = 0;
225 	len = 0;
226 
227 	/* Allocate enough memory at once. */
228 	list_for_each(pos, &bp->address_list) {
229 		len += sizeof(union sctp_addr_param);
230 	}
231 
232 	/* Don't even bother embedding an address if there
233 	 * is only one.
234 	 */
235 	if (len == sizeof(union sctp_addr_param)) {
236 		retval.v = NULL;
237 		goto end_raw;
238 	}
239 
240 	retval.v = kmalloc(len, gfp);
241 	if (!retval.v)
242 		goto end_raw;
243 
244 	addrparms = retval;
245 
246 	list_for_each_entry(addr, &bp->address_list, list) {
247 		af = sctp_get_af_specific(addr->a.v4.sin_family);
248 		len = af->to_addr_param(&addr->a, &rawaddr);
249 		memcpy(addrparms.v, &rawaddr, len);
250 		addrparms.v += len;
251 		addrparms_len += len;
252 	}
253 
254 end_raw:
255 	*addrs_len = addrparms_len;
256 	return retval;
257 }
258 
259 /*
260  * Create an address list out of the raw address list format (IPv4 and IPv6
261  * address parameters).
262  */
sctp_raw_to_bind_addrs(struct sctp_bind_addr * bp,__u8 * raw_addr_list,int addrs_len,__u16 port,gfp_t gfp)263 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
264 			   int addrs_len, __u16 port, gfp_t gfp)
265 {
266 	union sctp_addr_param *rawaddr;
267 	struct sctp_paramhdr *param;
268 	union sctp_addr addr;
269 	int retval = 0;
270 	int len;
271 	struct sctp_af *af;
272 
273 	/* Convert the raw address to standard address format */
274 	while (addrs_len) {
275 		param = (struct sctp_paramhdr *)raw_addr_list;
276 		rawaddr = (union sctp_addr_param *)raw_addr_list;
277 
278 		af = sctp_get_af_specific(param_type2af(param->type));
279 		if (unlikely(!af) ||
280 		    !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
281 			retval = -EINVAL;
282 			goto out_err;
283 		}
284 
285 		if (sctp_bind_addr_state(bp, &addr) != -1)
286 			goto next;
287 		retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
288 					    SCTP_ADDR_SRC, gfp);
289 		if (retval)
290 			/* Can't finish building the list, clean up. */
291 			goto out_err;
292 
293 next:
294 		len = ntohs(param->length);
295 		addrs_len -= len;
296 		raw_addr_list += len;
297 	}
298 
299 	return retval;
300 
301 out_err:
302 	if (retval)
303 		sctp_bind_addr_clean(bp);
304 
305 	return retval;
306 }
307 
308 /********************************************************************
309  * 2nd Level Abstractions
310  ********************************************************************/
311 
312 /* 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)313 int sctp_bind_addr_match(struct sctp_bind_addr *bp,
314 			 const union sctp_addr *addr,
315 			 struct sctp_sock *opt)
316 {
317 	struct sctp_sockaddr_entry *laddr;
318 	int match = 0;
319 
320 	rcu_read_lock();
321 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
322 		if (!laddr->valid)
323 			continue;
324 		if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
325 			match = 1;
326 			break;
327 		}
328 	}
329 	rcu_read_unlock();
330 
331 	return match;
332 }
333 
sctp_bind_addrs_check(struct sctp_sock * sp,struct sctp_sock * sp2,int cnt2)334 int sctp_bind_addrs_check(struct sctp_sock *sp,
335 			  struct sctp_sock *sp2, int cnt2)
336 {
337 	struct sctp_bind_addr *bp2 = &sp2->ep->base.bind_addr;
338 	struct sctp_bind_addr *bp = &sp->ep->base.bind_addr;
339 	struct sctp_sockaddr_entry *laddr, *laddr2;
340 	bool exist = false;
341 	int cnt = 0;
342 
343 	rcu_read_lock();
344 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
345 		list_for_each_entry_rcu(laddr2, &bp2->address_list, list) {
346 			if (sp->pf->af->cmp_addr(&laddr->a, &laddr2->a) &&
347 			    laddr->valid && laddr2->valid) {
348 				exist = true;
349 				goto next;
350 			}
351 		}
352 		cnt = 0;
353 		break;
354 next:
355 		cnt++;
356 	}
357 	rcu_read_unlock();
358 
359 	return (cnt == cnt2) ? 0 : (exist ? -EEXIST : 1);
360 }
361 
362 /* Does the address 'addr' conflict with any addresses in
363  * the bp.
364  */
sctp_bind_addr_conflict(struct sctp_bind_addr * bp,const union sctp_addr * addr,struct sctp_sock * bp_sp,struct sctp_sock * addr_sp)365 int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
366 			    const union sctp_addr *addr,
367 			    struct sctp_sock *bp_sp,
368 			    struct sctp_sock *addr_sp)
369 {
370 	struct sctp_sockaddr_entry *laddr;
371 	int conflict = 0;
372 	struct sctp_sock *sp;
373 
374 	/* Pick the IPv6 socket as the basis of comparison
375 	 * since it's usually a superset of the IPv4.
376 	 * If there is no IPv6 socket, then default to bind_addr.
377 	 */
378 	if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
379 		sp = bp_sp;
380 	else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
381 		sp = addr_sp;
382 	else
383 		sp = bp_sp;
384 
385 	rcu_read_lock();
386 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
387 		if (!laddr->valid)
388 			continue;
389 
390 		conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
391 		if (conflict)
392 			break;
393 	}
394 	rcu_read_unlock();
395 
396 	return conflict;
397 }
398 
399 /* 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)400 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
401 			 const union sctp_addr *addr)
402 {
403 	struct sctp_sockaddr_entry *laddr;
404 	struct sctp_af *af;
405 
406 	af = sctp_get_af_specific(addr->sa.sa_family);
407 	if (unlikely(!af))
408 		return -1;
409 
410 	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
411 		if (!laddr->valid)
412 			continue;
413 		if (af->cmp_addr(&laddr->a, addr))
414 			return laddr->state;
415 	}
416 
417 	return -1;
418 }
419 
420 /* Find the first address in the bind address list that is not present in
421  * the addrs packed array.
422  */
sctp_find_unmatch_addr(struct sctp_bind_addr * bp,const union sctp_addr * addrs,int addrcnt,struct sctp_sock * opt)423 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
424 					const union sctp_addr	*addrs,
425 					int			addrcnt,
426 					struct sctp_sock	*opt)
427 {
428 	struct sctp_sockaddr_entry	*laddr;
429 	union sctp_addr			*addr;
430 	void 				*addr_buf;
431 	struct sctp_af			*af;
432 	int				i;
433 
434 	/* This is only called sctp_send_asconf_del_ip() and we hold
435 	 * the socket lock in that code patch, so that address list
436 	 * can't change.
437 	 */
438 	list_for_each_entry(laddr, &bp->address_list, list) {
439 		addr_buf = (union sctp_addr *)addrs;
440 		for (i = 0; i < addrcnt; i++) {
441 			addr = addr_buf;
442 			af = sctp_get_af_specific(addr->v4.sin_family);
443 			if (!af)
444 				break;
445 
446 			if (opt->pf->cmp_addr(&laddr->a, addr, opt))
447 				break;
448 
449 			addr_buf += af->sockaddr_len;
450 		}
451 		if (i == addrcnt)
452 			return &laddr->a;
453 	}
454 
455 	return NULL;
456 }
457 
458 /* 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)459 static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
460 			      union sctp_addr *addr, enum sctp_scope scope,
461 			      gfp_t gfp, int flags)
462 {
463 	int error = 0;
464 
465 	if (sctp_is_any(NULL, addr)) {
466 		error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);
467 	} else if (sctp_in_scope(net, addr, scope)) {
468 		/* Now that the address is in scope, check to see if
469 		 * the address type is supported by local sock as
470 		 * well as the remote peer.
471 		 */
472 		if ((((AF_INET == addr->sa.sa_family) &&
473 		      (flags & SCTP_ADDR4_ALLOWED) &&
474 		      (flags & SCTP_ADDR4_PEERSUPP))) ||
475 		    (((AF_INET6 == addr->sa.sa_family) &&
476 		      (flags & SCTP_ADDR6_ALLOWED) &&
477 		      (flags & SCTP_ADDR6_PEERSUPP))))
478 			error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
479 						   SCTP_ADDR_SRC, gfp);
480 	}
481 
482 	return error;
483 }
484 
485 /* Is this a wildcard address?  */
sctp_is_any(struct sock * sk,const union sctp_addr * addr)486 int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
487 {
488 	unsigned short fam = 0;
489 	struct sctp_af *af;
490 
491 	/* Try to get the right address family */
492 	if (addr->sa.sa_family != AF_UNSPEC)
493 		fam = addr->sa.sa_family;
494 	else if (sk)
495 		fam = sk->sk_family;
496 
497 	af = sctp_get_af_specific(fam);
498 	if (!af)
499 		return 0;
500 
501 	return af->is_any(addr);
502 }
503 
504 /* Is 'addr' valid for 'scope'?  */
sctp_in_scope(struct net * net,const union sctp_addr * addr,enum sctp_scope scope)505 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
506 		  enum sctp_scope scope)
507 {
508 	enum sctp_scope addr_scope = sctp_scope(addr);
509 
510 	/* The unusable SCTP addresses will not be considered with
511 	 * any defined scopes.
512 	 */
513 	if (SCTP_SCOPE_UNUSABLE == addr_scope)
514 		return 0;
515 	/*
516 	 * For INIT and INIT-ACK address list, let L be the level of
517 	 * requested destination address, sender and receiver
518 	 * SHOULD include all of its addresses with level greater
519 	 * than or equal to L.
520 	 *
521 	 * Address scoping can be selectively controlled via sysctl
522 	 * option
523 	 */
524 	switch (net->sctp.scope_policy) {
525 	case SCTP_SCOPE_POLICY_DISABLE:
526 		return 1;
527 	case SCTP_SCOPE_POLICY_ENABLE:
528 		if (addr_scope <= scope)
529 			return 1;
530 		break;
531 	case SCTP_SCOPE_POLICY_PRIVATE:
532 		if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
533 			return 1;
534 		break;
535 	case SCTP_SCOPE_POLICY_LINK:
536 		if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
537 			return 1;
538 		break;
539 	default:
540 		break;
541 	}
542 
543 	return 0;
544 }
545 
sctp_is_ep_boundall(struct sock * sk)546 int sctp_is_ep_boundall(struct sock *sk)
547 {
548 	struct sctp_bind_addr *bp;
549 	struct sctp_sockaddr_entry *addr;
550 
551 	bp = &sctp_sk(sk)->ep->base.bind_addr;
552 	if (sctp_list_single_entry(&bp->address_list)) {
553 		addr = list_entry(bp->address_list.next,
554 				  struct sctp_sockaddr_entry, list);
555 		if (sctp_is_any(sk, &addr->a))
556 			return 1;
557 	}
558 	return 0;
559 }
560 
561 /********************************************************************
562  * 3rd Level Abstractions
563  ********************************************************************/
564 
565 /* What is the scope of 'addr'?  */
sctp_scope(const union sctp_addr * addr)566 enum sctp_scope sctp_scope(const union sctp_addr *addr)
567 {
568 	struct sctp_af *af;
569 
570 	af = sctp_get_af_specific(addr->sa.sa_family);
571 	if (!af)
572 		return SCTP_SCOPE_UNUSABLE;
573 
574 	return af->scope((union sctp_addr *)addr);
575 }
576