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. */
33static 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);
36static 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 */
43int 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
82out:
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 */
94int 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 */
117void 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. */
124static 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  */
137void 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. */
144int 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 */
179int 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 */
211union 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
254end_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 */
263int 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
293next:
294		len = ntohs(param->length);
295		addrs_len -= len;
296		raw_addr_list += len;
297	}
298
299	return retval;
300
301out_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. */
313int 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
334int 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;
354next:
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 */
365int 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 */
400int 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 */
423union 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. */
459static 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?  */
486int 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'?  */
505int 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
546int 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'?  */
566enum 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