treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104
[sfrench/cifs-2.6.git] / net / sctp / endpointola.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001-2002 International Business Machines, Corp.
6  * Copyright (c) 2001 Intel Corp.
7  * Copyright (c) 2001 Nokia, Inc.
8  * Copyright (c) 2001 La Monte H.P. Yarroll
9  *
10  * This file is part of the SCTP kernel implementation
11  *
12  * This abstraction represents an SCTP endpoint.
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  *    Jon Grimm <jgrimm@austin.ibm.com>
22  *    Daisy Chang <daisyc@us.ibm.com>
23  *    Dajiang Zhang <dajiang.zhang@nokia.com>
24  */
25
26 #include <linux/types.h>
27 #include <linux/slab.h>
28 #include <linux/in.h>
29 #include <linux/random.h>       /* get_random_bytes() */
30 #include <net/sock.h>
31 #include <net/ipv6.h>
32 #include <net/sctp/sctp.h>
33 #include <net/sctp/sm.h>
34
35 /* Forward declarations for internal helpers. */
36 static void sctp_endpoint_bh_rcv(struct work_struct *work);
37
38 /*
39  * Initialize the base fields of the endpoint structure.
40  */
41 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
42                                                 struct sock *sk,
43                                                 gfp_t gfp)
44 {
45         struct net *net = sock_net(sk);
46         struct sctp_hmac_algo_param *auth_hmacs = NULL;
47         struct sctp_chunks_param *auth_chunks = NULL;
48         struct sctp_shared_key *null_key;
49         int err;
50
51         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
52         if (!ep->digest)
53                 return NULL;
54
55         ep->auth_enable = net->sctp.auth_enable;
56         if (ep->auth_enable) {
57                 /* Allocate space for HMACS and CHUNKS authentication
58                  * variables.  There are arrays that we encode directly
59                  * into parameters to make the rest of the operations easier.
60                  */
61                 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
62                                                  SCTP_AUTH_NUM_HMACS), gfp);
63                 if (!auth_hmacs)
64                         goto nomem;
65
66                 auth_chunks = kzalloc(sizeof(*auth_chunks) +
67                                       SCTP_NUM_CHUNK_TYPES, gfp);
68                 if (!auth_chunks)
69                         goto nomem;
70
71                 /* Initialize the HMACS parameter.
72                  * SCTP-AUTH: Section 3.3
73                  *    Every endpoint supporting SCTP chunk authentication MUST
74                  *    support the HMAC based on the SHA-1 algorithm.
75                  */
76                 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
77                 auth_hmacs->param_hdr.length =
78                                         htons(sizeof(struct sctp_paramhdr) + 2);
79                 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
80
81                 /* Initialize the CHUNKS parameter */
82                 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
83                 auth_chunks->param_hdr.length =
84                                         htons(sizeof(struct sctp_paramhdr));
85
86                 /* If the Add-IP functionality is enabled, we must
87                  * authenticate, ASCONF and ASCONF-ACK chunks
88                  */
89                 if (net->sctp.addip_enable) {
90                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
91                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
92                         auth_chunks->param_hdr.length =
93                                         htons(sizeof(struct sctp_paramhdr) + 2);
94                 }
95
96                 /* Allocate and initialize transorms arrays for supported
97                  * HMACs.
98                  */
99                 err = sctp_auth_init_hmacs(ep, gfp);
100                 if (err)
101                         goto nomem;
102         }
103
104         /* Initialize the base structure. */
105         /* What type of endpoint are we?  */
106         ep->base.type = SCTP_EP_TYPE_SOCKET;
107
108         /* Initialize the basic object fields. */
109         refcount_set(&ep->base.refcnt, 1);
110         ep->base.dead = false;
111
112         /* Create an input queue.  */
113         sctp_inq_init(&ep->base.inqueue);
114
115         /* Set its top-half handler */
116         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
117
118         /* Initialize the bind addr area */
119         sctp_bind_addr_init(&ep->base.bind_addr, 0);
120
121         /* Remember who we are attached to.  */
122         ep->base.sk = sk;
123         sock_hold(ep->base.sk);
124
125         /* Create the lists of associations.  */
126         INIT_LIST_HEAD(&ep->asocs);
127
128         /* Use SCTP specific send buffer space queues.  */
129         ep->sndbuf_policy = net->sctp.sndbuf_policy;
130
131         sk->sk_data_ready = sctp_data_ready;
132         sk->sk_write_space = sctp_write_space;
133         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
134
135         /* Get the receive buffer policy for this endpoint */
136         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
137
138         /* Initialize the secret key used with cookie. */
139         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
140
141         /* SCTP-AUTH extensions*/
142         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
143         null_key = sctp_auth_shkey_create(0, gfp);
144         if (!null_key)
145                 goto nomem_shkey;
146
147         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
148
149         /* Add the null key to the endpoint shared keys list and
150          * set the hmcas and chunks pointers.
151          */
152         ep->auth_hmacs_list = auth_hmacs;
153         ep->auth_chunk_list = auth_chunks;
154         ep->prsctp_enable = net->sctp.prsctp_enable;
155         ep->reconf_enable = net->sctp.reconf_enable;
156
157         return ep;
158
159 nomem_shkey:
160         sctp_auth_destroy_hmacs(ep->auth_hmacs);
161 nomem:
162         /* Free all allocations */
163         kfree(auth_hmacs);
164         kfree(auth_chunks);
165         kfree(ep->digest);
166         return NULL;
167
168 }
169
170 /* Create a sctp_endpoint with all that boring stuff initialized.
171  * Returns NULL if there isn't enough memory.
172  */
173 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
174 {
175         struct sctp_endpoint *ep;
176
177         /* Build a local endpoint. */
178         ep = kzalloc(sizeof(*ep), gfp);
179         if (!ep)
180                 goto fail;
181
182         if (!sctp_endpoint_init(ep, sk, gfp))
183                 goto fail_init;
184
185         SCTP_DBG_OBJCNT_INC(ep);
186         return ep;
187
188 fail_init:
189         kfree(ep);
190 fail:
191         return NULL;
192 }
193
194 /* Add an association to an endpoint.  */
195 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
196                             struct sctp_association *asoc)
197 {
198         struct sock *sk = ep->base.sk;
199
200         /* If this is a temporary association, don't bother
201          * since we'll be removing it shortly and don't
202          * want anyone to find it anyway.
203          */
204         if (asoc->temp)
205                 return;
206
207         /* Now just add it to our list of asocs */
208         list_add_tail(&asoc->asocs, &ep->asocs);
209
210         /* Increment the backlog value for a TCP-style listening socket. */
211         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
212                 sk->sk_ack_backlog++;
213 }
214
215 /* Free the endpoint structure.  Delay cleanup until
216  * all users have released their reference count on this structure.
217  */
218 void sctp_endpoint_free(struct sctp_endpoint *ep)
219 {
220         ep->base.dead = true;
221
222         inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
223
224         /* Unlink this endpoint, so we can't find it again! */
225         sctp_unhash_endpoint(ep);
226
227         sctp_endpoint_put(ep);
228 }
229
230 /* Final destructor for endpoint.  */
231 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
232 {
233         struct sock *sk;
234
235         if (unlikely(!ep->base.dead)) {
236                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
237                 return;
238         }
239
240         /* Free the digest buffer */
241         kfree(ep->digest);
242
243         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
244          * chunks and hmacs arrays that were allocated
245          */
246         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
247         kfree(ep->auth_hmacs_list);
248         kfree(ep->auth_chunk_list);
249
250         /* AUTH - Free any allocated HMAC transform containers */
251         sctp_auth_destroy_hmacs(ep->auth_hmacs);
252
253         /* Cleanup. */
254         sctp_inq_free(&ep->base.inqueue);
255         sctp_bind_addr_free(&ep->base.bind_addr);
256
257         memset(ep->secret_key, 0, sizeof(ep->secret_key));
258
259         sk = ep->base.sk;
260         /* Remove and free the port */
261         if (sctp_sk(sk)->bind_hash)
262                 sctp_put_port(sk);
263
264         sctp_sk(sk)->ep = NULL;
265         /* Give up our hold on the sock */
266         sock_put(sk);
267
268         kfree(ep);
269         SCTP_DBG_OBJCNT_DEC(ep);
270 }
271
272 /* Hold a reference to an endpoint. */
273 void sctp_endpoint_hold(struct sctp_endpoint *ep)
274 {
275         refcount_inc(&ep->base.refcnt);
276 }
277
278 /* Release a reference to an endpoint and clean up if there are
279  * no more references.
280  */
281 void sctp_endpoint_put(struct sctp_endpoint *ep)
282 {
283         if (refcount_dec_and_test(&ep->base.refcnt))
284                 sctp_endpoint_destroy(ep);
285 }
286
287 /* Is this the endpoint we are looking for?  */
288 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
289                                                struct net *net,
290                                                const union sctp_addr *laddr)
291 {
292         struct sctp_endpoint *retval = NULL;
293
294         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
295             net_eq(sock_net(ep->base.sk), net)) {
296                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
297                                          sctp_sk(ep->base.sk)))
298                         retval = ep;
299         }
300
301         return retval;
302 }
303
304 /* Find the association that goes with this chunk.
305  * We lookup the transport from hashtable at first, then get association
306  * through t->assoc.
307  */
308 struct sctp_association *sctp_endpoint_lookup_assoc(
309         const struct sctp_endpoint *ep,
310         const union sctp_addr *paddr,
311         struct sctp_transport **transport)
312 {
313         struct sctp_association *asoc = NULL;
314         struct sctp_transport *t;
315
316         *transport = NULL;
317
318         /* If the local port is not set, there can't be any associations
319          * on this endpoint.
320          */
321         if (!ep->base.bind_addr.port)
322                 return NULL;
323
324         rcu_read_lock();
325         t = sctp_epaddr_lookup_transport(ep, paddr);
326         if (!t)
327                 goto out;
328
329         *transport = t;
330         asoc = t->asoc;
331 out:
332         rcu_read_unlock();
333         return asoc;
334 }
335
336 /* Look for any peeled off association from the endpoint that matches the
337  * given peer address.
338  */
339 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
340                                  const union sctp_addr *paddr)
341 {
342         struct sctp_sockaddr_entry *addr;
343         struct sctp_bind_addr *bp;
344         struct net *net = sock_net(ep->base.sk);
345
346         bp = &ep->base.bind_addr;
347         /* This function is called with the socket lock held,
348          * so the address_list can not change.
349          */
350         list_for_each_entry(addr, &bp->address_list, list) {
351                 if (sctp_has_association(net, &addr->a, paddr))
352                         return true;
353         }
354
355         return false;
356 }
357
358 /* Do delayed input processing.  This is scheduled by sctp_rcv().
359  * This may be called on BH or task time.
360  */
361 static void sctp_endpoint_bh_rcv(struct work_struct *work)
362 {
363         struct sctp_endpoint *ep =
364                 container_of(work, struct sctp_endpoint,
365                              base.inqueue.immediate);
366         struct sctp_association *asoc;
367         struct sock *sk;
368         struct net *net;
369         struct sctp_transport *transport;
370         struct sctp_chunk *chunk;
371         struct sctp_inq *inqueue;
372         union sctp_subtype subtype;
373         enum sctp_state state;
374         int error = 0;
375         int first_time = 1;     /* is this the first time through the loop */
376
377         if (ep->base.dead)
378                 return;
379
380         asoc = NULL;
381         inqueue = &ep->base.inqueue;
382         sk = ep->base.sk;
383         net = sock_net(sk);
384
385         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
386                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
387
388                 /* If the first chunk in the packet is AUTH, do special
389                  * processing specified in Section 6.3 of SCTP-AUTH spec
390                  */
391                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
392                         struct sctp_chunkhdr *next_hdr;
393
394                         next_hdr = sctp_inq_peek(inqueue);
395                         if (!next_hdr)
396                                 goto normal;
397
398                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
399                          * chunk while saving a pointer to it so we can do
400                          * Authentication later (during cookie-echo
401                          * processing).
402                          */
403                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
404                                 chunk->auth_chunk = skb_clone(chunk->skb,
405                                                                 GFP_ATOMIC);
406                                 chunk->auth = 1;
407                                 continue;
408                         }
409                 }
410 normal:
411                 /* We might have grown an association since last we
412                  * looked, so try again.
413                  *
414                  * This happens when we've just processed our
415                  * COOKIE-ECHO chunk.
416                  */
417                 if (NULL == chunk->asoc) {
418                         asoc = sctp_endpoint_lookup_assoc(ep,
419                                                           sctp_source(chunk),
420                                                           &transport);
421                         chunk->asoc = asoc;
422                         chunk->transport = transport;
423                 }
424
425                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
426                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
427                         continue;
428
429                 /* Remember where the last DATA chunk came from so we
430                  * know where to send the SACK.
431                  */
432                 if (asoc && sctp_chunk_is_data(chunk))
433                         asoc->peer.last_data_from = chunk->transport;
434                 else {
435                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
436                         if (asoc)
437                                 asoc->stats.ictrlchunks++;
438                 }
439
440                 if (chunk->transport)
441                         chunk->transport->last_time_heard = ktime_get();
442
443                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
444                                    ep, asoc, chunk, GFP_ATOMIC);
445
446                 if (error && chunk)
447                         chunk->pdiscard = 1;
448
449                 /* Check to see if the endpoint is freed in response to
450                  * the incoming chunk. If so, get out of the while loop.
451                  */
452                 if (!sctp_sk(sk)->ep)
453                         break;
454
455                 if (first_time)
456                         first_time = 0;
457         }
458 }