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) 2001-2003 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 | * These functions handle all input from the IP layer into SCTP. |
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 | * Xingang Guo <xingang.guo@intel.com> |
22 | * Jon Grimm <jgrimm@us.ibm.com> |
23 | * Hui Huang <hui.huang@nokia.com> |
24 | * Daisy Chang <daisyc@us.ibm.com> |
25 | * Sridhar Samudrala <sri@us.ibm.com> |
26 | * Ardelle Fan <ardelle.fan@intel.com> |
27 | */ |
28 | |
29 | #include <linux/types.h> |
30 | #include <linux/list.h> /* For struct list_head */ |
31 | #include <linux/socket.h> |
32 | #include <linux/ip.h> |
33 | #include <linux/time.h> /* For struct timeval */ |
34 | #include <linux/slab.h> |
35 | #include <net/ip.h> |
36 | #include <net/icmp.h> |
37 | #include <net/snmp.h> |
38 | #include <net/sock.h> |
39 | #include <net/xfrm.h> |
40 | #include <net/sctp/sctp.h> |
41 | #include <net/sctp/sm.h> |
42 | #include <net/sctp/checksum.h> |
43 | #include <net/net_namespace.h> |
44 | #include <linux/rhashtable.h> |
45 | #include <net/sock_reuseport.h> |
46 | |
47 | /* Forward declarations for internal helpers. */ |
48 | static int sctp_rcv_ootb(struct sk_buff *); |
49 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
50 | struct sk_buff *skb, |
51 | const union sctp_addr *paddr, |
52 | const union sctp_addr *laddr, |
53 | struct sctp_transport **transportp, |
54 | int dif, int sdif); |
55 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint( |
56 | struct net *net, struct sk_buff *skb, |
57 | const union sctp_addr *laddr, |
58 | const union sctp_addr *daddr, |
59 | int dif, int sdif); |
60 | static struct sctp_association *__sctp_lookup_association( |
61 | struct net *net, |
62 | const union sctp_addr *local, |
63 | const union sctp_addr *peer, |
64 | struct sctp_transport **pt, |
65 | int dif, int sdif); |
66 | |
67 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
68 | |
69 | |
70 | /* Calculate the SCTP checksum of an SCTP packet. */ |
71 | static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) |
72 | { |
73 | struct sctphdr *sh = sctp_hdr(skb); |
74 | __le32 cmp = sh->checksum; |
75 | __le32 val = sctp_compute_cksum(skb, offset: 0); |
76 | |
77 | if (val != cmp) { |
78 | /* CRC failure, dump it. */ |
79 | __SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS); |
80 | return -1; |
81 | } |
82 | return 0; |
83 | } |
84 | |
85 | /* |
86 | * This is the routine which IP calls when receiving an SCTP packet. |
87 | */ |
88 | int sctp_rcv(struct sk_buff *skb) |
89 | { |
90 | struct sock *sk; |
91 | struct sctp_association *asoc; |
92 | struct sctp_endpoint *ep = NULL; |
93 | struct sctp_ep_common *rcvr; |
94 | struct sctp_transport *transport = NULL; |
95 | struct sctp_chunk *chunk; |
96 | union sctp_addr src; |
97 | union sctp_addr dest; |
98 | int family; |
99 | struct sctp_af *af; |
100 | struct net *net = dev_net(dev: skb->dev); |
101 | bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb); |
102 | int dif, sdif; |
103 | |
104 | if (skb->pkt_type != PACKET_HOST) |
105 | goto discard_it; |
106 | |
107 | __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS); |
108 | |
109 | /* If packet is too small to contain a single chunk, let's not |
110 | * waste time on it anymore. |
111 | */ |
112 | if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + |
113 | skb_transport_offset(skb)) |
114 | goto discard_it; |
115 | |
116 | /* If the packet is fragmented and we need to do crc checking, |
117 | * it's better to just linearize it otherwise crc computing |
118 | * takes longer. |
119 | */ |
120 | if ((!is_gso && skb_linearize(skb)) || |
121 | !pskb_may_pull(skb, len: sizeof(struct sctphdr))) |
122 | goto discard_it; |
123 | |
124 | /* Pull up the IP header. */ |
125 | __skb_pull(skb, len: skb_transport_offset(skb)); |
126 | |
127 | skb->csum_valid = 0; /* Previous value not applicable */ |
128 | if (skb_csum_unnecessary(skb)) |
129 | __skb_decr_checksum_unnecessary(skb); |
130 | else if (!sctp_checksum_disable && |
131 | !is_gso && |
132 | sctp_rcv_checksum(net, skb) < 0) |
133 | goto discard_it; |
134 | skb->csum_valid = 1; |
135 | |
136 | __skb_pull(skb, len: sizeof(struct sctphdr)); |
137 | |
138 | family = ipver2af(ipver: ip_hdr(skb)->version); |
139 | af = sctp_get_af_specific(family); |
140 | if (unlikely(!af)) |
141 | goto discard_it; |
142 | SCTP_INPUT_CB(skb)->af = af; |
143 | |
144 | /* Initialize local addresses for lookups. */ |
145 | af->from_skb(&src, skb, 1); |
146 | af->from_skb(&dest, skb, 0); |
147 | dif = af->skb_iif(skb); |
148 | sdif = af->skb_sdif(skb); |
149 | |
150 | /* If the packet is to or from a non-unicast address, |
151 | * silently discard the packet. |
152 | * |
153 | * This is not clearly defined in the RFC except in section |
154 | * 8.4 - OOTB handling. However, based on the book "Stream Control |
155 | * Transmission Protocol" 2.1, "It is important to note that the |
156 | * IP address of an SCTP transport address must be a routable |
157 | * unicast address. In other words, IP multicast addresses and |
158 | * IP broadcast addresses cannot be used in an SCTP transport |
159 | * address." |
160 | */ |
161 | if (!af->addr_valid(&src, NULL, skb) || |
162 | !af->addr_valid(&dest, NULL, skb)) |
163 | goto discard_it; |
164 | |
165 | asoc = __sctp_rcv_lookup(net, skb, paddr: &src, laddr: &dest, transportp: &transport, dif, sdif); |
166 | |
167 | if (!asoc) |
168 | ep = __sctp_rcv_lookup_endpoint(net, skb, laddr: &dest, daddr: &src, dif, sdif); |
169 | |
170 | /* Retrieve the common input handling substructure. */ |
171 | rcvr = asoc ? &asoc->base : &ep->base; |
172 | sk = rcvr->sk; |
173 | |
174 | /* |
175 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. |
176 | * An SCTP packet is called an "out of the blue" (OOTB) |
177 | * packet if it is correctly formed, i.e., passed the |
178 | * receiver's checksum check, but the receiver is not |
179 | * able to identify the association to which this |
180 | * packet belongs. |
181 | */ |
182 | if (!asoc) { |
183 | if (sctp_rcv_ootb(skb)) { |
184 | __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); |
185 | goto discard_release; |
186 | } |
187 | } |
188 | |
189 | if (!xfrm_policy_check(sk, dir: XFRM_POLICY_IN, skb, family)) |
190 | goto discard_release; |
191 | nf_reset_ct(skb); |
192 | |
193 | if (sk_filter(sk, skb)) |
194 | goto discard_release; |
195 | |
196 | /* Create an SCTP packet structure. */ |
197 | chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC); |
198 | if (!chunk) |
199 | goto discard_release; |
200 | SCTP_INPUT_CB(skb)->chunk = chunk; |
201 | |
202 | /* Remember what endpoint is to handle this packet. */ |
203 | chunk->rcvr = rcvr; |
204 | |
205 | /* Remember the SCTP header. */ |
206 | chunk->sctp_hdr = sctp_hdr(skb); |
207 | |
208 | /* Set the source and destination addresses of the incoming chunk. */ |
209 | sctp_init_addrs(chunk, &src, &dest); |
210 | |
211 | /* Remember where we came from. */ |
212 | chunk->transport = transport; |
213 | |
214 | /* Acquire access to the sock lock. Note: We are safe from other |
215 | * bottom halves on this lock, but a user may be in the lock too, |
216 | * so check if it is busy. |
217 | */ |
218 | bh_lock_sock(sk); |
219 | |
220 | if (sk != rcvr->sk) { |
221 | /* Our cached sk is different from the rcvr->sk. This is |
222 | * because migrate()/accept() may have moved the association |
223 | * to a new socket and released all the sockets. So now we |
224 | * are holding a lock on the old socket while the user may |
225 | * be doing something with the new socket. Switch our veiw |
226 | * of the current sk. |
227 | */ |
228 | bh_unlock_sock(sk); |
229 | sk = rcvr->sk; |
230 | bh_lock_sock(sk); |
231 | } |
232 | |
233 | if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { |
234 | if (sctp_add_backlog(sk, skb)) { |
235 | bh_unlock_sock(sk); |
236 | sctp_chunk_free(chunk); |
237 | skb = NULL; /* sctp_chunk_free already freed the skb */ |
238 | goto discard_release; |
239 | } |
240 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG); |
241 | } else { |
242 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
243 | sctp_inq_push(&chunk->rcvr->inqueue, packet: chunk); |
244 | } |
245 | |
246 | bh_unlock_sock(sk); |
247 | |
248 | /* Release the asoc/ep ref we took in the lookup calls. */ |
249 | if (transport) |
250 | sctp_transport_put(transport); |
251 | else |
252 | sctp_endpoint_put(ep); |
253 | |
254 | return 0; |
255 | |
256 | discard_it: |
257 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); |
258 | kfree_skb(skb); |
259 | return 0; |
260 | |
261 | discard_release: |
262 | /* Release the asoc/ep ref we took in the lookup calls. */ |
263 | if (transport) |
264 | sctp_transport_put(transport); |
265 | else |
266 | sctp_endpoint_put(ep); |
267 | |
268 | goto discard_it; |
269 | } |
270 | |
271 | /* Process the backlog queue of the socket. Every skb on |
272 | * the backlog holds a ref on an association or endpoint. |
273 | * We hold this ref throughout the state machine to make |
274 | * sure that the structure we need is still around. |
275 | */ |
276 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) |
277 | { |
278 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
279 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
280 | struct sctp_transport *t = chunk->transport; |
281 | struct sctp_ep_common *rcvr = NULL; |
282 | int backloged = 0; |
283 | |
284 | rcvr = chunk->rcvr; |
285 | |
286 | /* If the rcvr is dead then the association or endpoint |
287 | * has been deleted and we can safely drop the chunk |
288 | * and refs that we are holding. |
289 | */ |
290 | if (rcvr->dead) { |
291 | sctp_chunk_free(chunk); |
292 | goto done; |
293 | } |
294 | |
295 | if (unlikely(rcvr->sk != sk)) { |
296 | /* In this case, the association moved from one socket to |
297 | * another. We are currently sitting on the backlog of the |
298 | * old socket, so we need to move. |
299 | * However, since we are here in the process context we |
300 | * need to take make sure that the user doesn't own |
301 | * the new socket when we process the packet. |
302 | * If the new socket is user-owned, queue the chunk to the |
303 | * backlog of the new socket without dropping any refs. |
304 | * Otherwise, we can safely push the chunk on the inqueue. |
305 | */ |
306 | |
307 | sk = rcvr->sk; |
308 | local_bh_disable(); |
309 | bh_lock_sock(sk); |
310 | |
311 | if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { |
312 | if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) |
313 | sctp_chunk_free(chunk); |
314 | else |
315 | backloged = 1; |
316 | } else |
317 | sctp_inq_push(inqueue, packet: chunk); |
318 | |
319 | bh_unlock_sock(sk); |
320 | local_bh_enable(); |
321 | |
322 | /* If the chunk was backloged again, don't drop refs */ |
323 | if (backloged) |
324 | return 0; |
325 | } else { |
326 | if (!sctp_newsk_ready(sk)) { |
327 | if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) |
328 | return 0; |
329 | sctp_chunk_free(chunk); |
330 | } else { |
331 | sctp_inq_push(inqueue, packet: chunk); |
332 | } |
333 | } |
334 | |
335 | done: |
336 | /* Release the refs we took in sctp_add_backlog */ |
337 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) |
338 | sctp_transport_put(t); |
339 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) |
340 | sctp_endpoint_put(sctp_ep(base: rcvr)); |
341 | else |
342 | BUG(); |
343 | |
344 | return 0; |
345 | } |
346 | |
347 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
348 | { |
349 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
350 | struct sctp_transport *t = chunk->transport; |
351 | struct sctp_ep_common *rcvr = chunk->rcvr; |
352 | int ret; |
353 | |
354 | ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); |
355 | if (!ret) { |
356 | /* Hold the assoc/ep while hanging on the backlog queue. |
357 | * This way, we know structures we need will not disappear |
358 | * from us |
359 | */ |
360 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) |
361 | sctp_transport_hold(t); |
362 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) |
363 | sctp_endpoint_hold(ep: sctp_ep(base: rcvr)); |
364 | else |
365 | BUG(); |
366 | } |
367 | return ret; |
368 | |
369 | } |
370 | |
371 | /* Handle icmp frag needed error. */ |
372 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, |
373 | struct sctp_transport *t, __u32 pmtu) |
374 | { |
375 | if (!t || |
376 | (t->pathmtu <= pmtu && |
377 | t->pl.probe_size + sctp_transport_pl_hlen(t) <= pmtu)) |
378 | return; |
379 | |
380 | if (sock_owned_by_user(sk)) { |
381 | atomic_set(v: &t->mtu_info, i: pmtu); |
382 | asoc->pmtu_pending = 1; |
383 | t->pmtu_pending = 1; |
384 | return; |
385 | } |
386 | |
387 | if (!(t->param_flags & SPP_PMTUD_ENABLE)) |
388 | /* We can't allow retransmitting in such case, as the |
389 | * retransmission would be sized just as before, and thus we |
390 | * would get another icmp, and retransmit again. |
391 | */ |
392 | return; |
393 | |
394 | /* Update transports view of the MTU. Return if no update was needed. |
395 | * If an update wasn't needed/possible, it also doesn't make sense to |
396 | * try to retransmit now. |
397 | */ |
398 | if (!sctp_transport_update_pmtu(t, pmtu)) |
399 | return; |
400 | |
401 | /* Update association pmtu. */ |
402 | sctp_assoc_sync_pmtu(asoc); |
403 | |
404 | /* Retransmit with the new pmtu setting. */ |
405 | sctp_retransmit(q: &asoc->outqueue, transport: t, reason: SCTP_RTXR_PMTUD); |
406 | } |
407 | |
408 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
409 | struct sk_buff *skb) |
410 | { |
411 | struct dst_entry *dst; |
412 | |
413 | if (sock_owned_by_user(sk) || !t) |
414 | return; |
415 | dst = sctp_transport_dst_check(t); |
416 | if (dst) |
417 | dst->ops->redirect(dst, sk, skb); |
418 | } |
419 | |
420 | /* |
421 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures |
422 | * |
423 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" |
424 | * or a "Protocol Unreachable" treat this message as an abort |
425 | * with the T bit set. |
426 | * |
427 | * This function sends an event to the state machine, which will abort the |
428 | * association. |
429 | * |
430 | */ |
431 | void sctp_icmp_proto_unreachable(struct sock *sk, |
432 | struct sctp_association *asoc, |
433 | struct sctp_transport *t) |
434 | { |
435 | if (sock_owned_by_user(sk)) { |
436 | if (timer_pending(timer: &t->proto_unreach_timer)) |
437 | return; |
438 | else { |
439 | if (!mod_timer(timer: &t->proto_unreach_timer, |
440 | expires: jiffies + (HZ/20))) |
441 | sctp_transport_hold(t); |
442 | } |
443 | } else { |
444 | struct net *net = sock_net(sk); |
445 | |
446 | pr_debug("%s: unrecognized next header type " |
447 | "encountered!\n" , __func__); |
448 | |
449 | if (del_timer(timer: &t->proto_unreach_timer)) |
450 | sctp_transport_put(t); |
451 | |
452 | sctp_do_sm(net, event_type: SCTP_EVENT_T_OTHER, |
453 | subtype: SCTP_ST_OTHER(arg: SCTP_EVENT_ICMP_PROTO_UNREACH), |
454 | state: asoc->state, ep: asoc->ep, asoc, event_arg: t, |
455 | GFP_ATOMIC); |
456 | } |
457 | } |
458 | |
459 | /* Common lookup code for icmp/icmpv6 error handler. */ |
460 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
461 | struct sctphdr *sctphdr, |
462 | struct sctp_association **app, |
463 | struct sctp_transport **tpp) |
464 | { |
465 | struct sctp_init_chunk *chunkhdr, _chunkhdr; |
466 | union sctp_addr saddr; |
467 | union sctp_addr daddr; |
468 | struct sctp_af *af; |
469 | struct sock *sk = NULL; |
470 | struct sctp_association *asoc; |
471 | struct sctp_transport *transport = NULL; |
472 | __u32 vtag = ntohl(sctphdr->vtag); |
473 | int sdif = inet_sdif(skb); |
474 | int dif = inet_iif(skb); |
475 | |
476 | *app = NULL; *tpp = NULL; |
477 | |
478 | af = sctp_get_af_specific(family); |
479 | if (unlikely(!af)) { |
480 | return NULL; |
481 | } |
482 | |
483 | /* Initialize local addresses for lookups. */ |
484 | af->from_skb(&saddr, skb, 1); |
485 | af->from_skb(&daddr, skb, 0); |
486 | |
487 | /* Look for an association that matches the incoming ICMP error |
488 | * packet. |
489 | */ |
490 | asoc = __sctp_lookup_association(net, local: &saddr, peer: &daddr, pt: &transport, dif, sdif); |
491 | if (!asoc) |
492 | return NULL; |
493 | |
494 | sk = asoc->base.sk; |
495 | |
496 | /* RFC 4960, Appendix C. ICMP Handling |
497 | * |
498 | * ICMP6) An implementation MUST validate that the Verification Tag |
499 | * contained in the ICMP message matches the Verification Tag of |
500 | * the peer. If the Verification Tag is not 0 and does NOT |
501 | * match, discard the ICMP message. If it is 0 and the ICMP |
502 | * message contains enough bytes to verify that the chunk type is |
503 | * an INIT chunk and that the Initiate Tag matches the tag of the |
504 | * peer, continue with ICMP7. If the ICMP message is too short |
505 | * or the chunk type or the Initiate Tag does not match, silently |
506 | * discard the packet. |
507 | */ |
508 | if (vtag == 0) { |
509 | /* chunk header + first 4 octects of init header */ |
510 | chunkhdr = skb_header_pointer(skb, offset: skb_transport_offset(skb) + |
511 | sizeof(struct sctphdr), |
512 | len: sizeof(struct sctp_chunkhdr) + |
513 | sizeof(__be32), buffer: &_chunkhdr); |
514 | if (!chunkhdr || |
515 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || |
516 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) |
517 | goto out; |
518 | |
519 | } else if (vtag != asoc->c.peer_vtag) { |
520 | goto out; |
521 | } |
522 | |
523 | bh_lock_sock(sk); |
524 | |
525 | /* If too many ICMPs get dropped on busy |
526 | * servers this needs to be solved differently. |
527 | */ |
528 | if (sock_owned_by_user(sk)) |
529 | __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); |
530 | |
531 | *app = asoc; |
532 | *tpp = transport; |
533 | return sk; |
534 | |
535 | out: |
536 | sctp_transport_put(transport); |
537 | return NULL; |
538 | } |
539 | |
540 | /* Common cleanup code for icmp/icmpv6 error handler. */ |
541 | void sctp_err_finish(struct sock *sk, struct sctp_transport *t) |
542 | __releases(&((__sk)->sk_lock.slock)) |
543 | { |
544 | bh_unlock_sock(sk); |
545 | sctp_transport_put(t); |
546 | } |
547 | |
548 | static void sctp_v4_err_handle(struct sctp_transport *t, struct sk_buff *skb, |
549 | __u8 type, __u8 code, __u32 info) |
550 | { |
551 | struct sctp_association *asoc = t->asoc; |
552 | struct sock *sk = asoc->base.sk; |
553 | int err = 0; |
554 | |
555 | switch (type) { |
556 | case ICMP_PARAMETERPROB: |
557 | err = EPROTO; |
558 | break; |
559 | case ICMP_DEST_UNREACH: |
560 | if (code > NR_ICMP_UNREACH) |
561 | return; |
562 | if (code == ICMP_FRAG_NEEDED) { |
563 | sctp_icmp_frag_needed(sk, asoc, t, SCTP_TRUNC4(info)); |
564 | return; |
565 | } |
566 | if (code == ICMP_PROT_UNREACH) { |
567 | sctp_icmp_proto_unreachable(sk, asoc, t); |
568 | return; |
569 | } |
570 | err = icmp_err_convert[code].errno; |
571 | break; |
572 | case ICMP_TIME_EXCEEDED: |
573 | if (code == ICMP_EXC_FRAGTIME) |
574 | return; |
575 | |
576 | err = EHOSTUNREACH; |
577 | break; |
578 | case ICMP_REDIRECT: |
579 | sctp_icmp_redirect(sk, t, skb); |
580 | return; |
581 | default: |
582 | return; |
583 | } |
584 | if (!sock_owned_by_user(sk) && inet_test_bit(RECVERR, sk)) { |
585 | sk->sk_err = err; |
586 | sk_error_report(sk); |
587 | } else { /* Only an error on timeout */ |
588 | WRITE_ONCE(sk->sk_err_soft, err); |
589 | } |
590 | } |
591 | |
592 | /* |
593 | * This routine is called by the ICMP module when it gets some |
594 | * sort of error condition. If err < 0 then the socket should |
595 | * be closed and the error returned to the user. If err > 0 |
596 | * it's just the icmp type << 8 | icmp code. After adjustment |
597 | * header points to the first 8 bytes of the sctp header. We need |
598 | * to find the appropriate port. |
599 | * |
600 | * The locking strategy used here is very "optimistic". When |
601 | * someone else accesses the socket the ICMP is just dropped |
602 | * and for some paths there is no check at all. |
603 | * A more general error queue to queue errors for later handling |
604 | * is probably better. |
605 | * |
606 | */ |
607 | int sctp_v4_err(struct sk_buff *skb, __u32 info) |
608 | { |
609 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
610 | const int type = icmp_hdr(skb)->type; |
611 | const int code = icmp_hdr(skb)->code; |
612 | struct net *net = dev_net(dev: skb->dev); |
613 | struct sctp_transport *transport; |
614 | struct sctp_association *asoc; |
615 | __u16 saveip, savesctp; |
616 | struct sock *sk; |
617 | |
618 | /* Fix up skb to look at the embedded net header. */ |
619 | saveip = skb->network_header; |
620 | savesctp = skb->transport_header; |
621 | skb_reset_network_header(skb); |
622 | skb_set_transport_header(skb, offset: iph->ihl * 4); |
623 | sk = sctp_err_lookup(net, AF_INET, skb, sctphdr: sctp_hdr(skb), app: &asoc, tpp: &transport); |
624 | /* Put back, the original values. */ |
625 | skb->network_header = saveip; |
626 | skb->transport_header = savesctp; |
627 | if (!sk) { |
628 | __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
629 | return -ENOENT; |
630 | } |
631 | |
632 | sctp_v4_err_handle(t: transport, skb, type, code, info); |
633 | sctp_err_finish(sk, t: transport); |
634 | |
635 | return 0; |
636 | } |
637 | |
638 | int sctp_udp_v4_err(struct sock *sk, struct sk_buff *skb) |
639 | { |
640 | struct net *net = dev_net(dev: skb->dev); |
641 | struct sctp_association *asoc; |
642 | struct sctp_transport *t; |
643 | struct icmphdr *hdr; |
644 | __u32 info = 0; |
645 | |
646 | skb->transport_header += sizeof(struct udphdr); |
647 | sk = sctp_err_lookup(net, AF_INET, skb, sctphdr: sctp_hdr(skb), app: &asoc, tpp: &t); |
648 | if (!sk) { |
649 | __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
650 | return -ENOENT; |
651 | } |
652 | |
653 | skb->transport_header -= sizeof(struct udphdr); |
654 | hdr = (struct icmphdr *)(skb_network_header(skb) - sizeof(struct icmphdr)); |
655 | if (hdr->type == ICMP_REDIRECT) { |
656 | /* can't be handled without outer iphdr known, leave it to udp_err */ |
657 | sctp_err_finish(sk, t); |
658 | return 0; |
659 | } |
660 | if (hdr->type == ICMP_DEST_UNREACH && hdr->code == ICMP_FRAG_NEEDED) |
661 | info = ntohs(hdr->un.frag.mtu); |
662 | sctp_v4_err_handle(t, skb, type: hdr->type, code: hdr->code, info); |
663 | |
664 | sctp_err_finish(sk, t); |
665 | return 1; |
666 | } |
667 | |
668 | /* |
669 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. |
670 | * |
671 | * This function scans all the chunks in the OOTB packet to determine if |
672 | * the packet should be discarded right away. If a response might be needed |
673 | * for this packet, or, if further processing is possible, the packet will |
674 | * be queued to a proper inqueue for the next phase of handling. |
675 | * |
676 | * Output: |
677 | * Return 0 - If further processing is needed. |
678 | * Return 1 - If the packet can be discarded right away. |
679 | */ |
680 | static int sctp_rcv_ootb(struct sk_buff *skb) |
681 | { |
682 | struct sctp_chunkhdr *ch, _ch; |
683 | int ch_end, offset = 0; |
684 | |
685 | /* Scan through all the chunks in the packet. */ |
686 | do { |
687 | /* Make sure we have at least the header there */ |
688 | if (offset + sizeof(_ch) > skb->len) |
689 | break; |
690 | |
691 | ch = skb_header_pointer(skb, offset, len: sizeof(*ch), buffer: &_ch); |
692 | |
693 | /* Break out if chunk length is less then minimal. */ |
694 | if (!ch || ntohs(ch->length) < sizeof(_ch)) |
695 | break; |
696 | |
697 | ch_end = offset + SCTP_PAD4(ntohs(ch->length)); |
698 | if (ch_end > skb->len) |
699 | break; |
700 | |
701 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the |
702 | * receiver MUST silently discard the OOTB packet and take no |
703 | * further action. |
704 | */ |
705 | if (SCTP_CID_ABORT == ch->type) |
706 | goto discard; |
707 | |
708 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE |
709 | * chunk, the receiver should silently discard the packet |
710 | * and take no further action. |
711 | */ |
712 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) |
713 | goto discard; |
714 | |
715 | /* RFC 4460, 2.11.2 |
716 | * This will discard packets with INIT chunk bundled as |
717 | * subsequent chunks in the packet. When INIT is first, |
718 | * the normal INIT processing will discard the chunk. |
719 | */ |
720 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) |
721 | goto discard; |
722 | |
723 | offset = ch_end; |
724 | } while (ch_end < skb->len); |
725 | |
726 | return 0; |
727 | |
728 | discard: |
729 | return 1; |
730 | } |
731 | |
732 | /* Insert endpoint into the hash table. */ |
733 | static int __sctp_hash_endpoint(struct sctp_endpoint *ep) |
734 | { |
735 | struct sock *sk = ep->base.sk; |
736 | struct net *net = sock_net(sk); |
737 | struct sctp_hashbucket *head; |
738 | |
739 | ep->hashent = sctp_ep_hashfn(net, lport: ep->base.bind_addr.port); |
740 | head = &sctp_ep_hashtable[ep->hashent]; |
741 | |
742 | if (sk->sk_reuseport) { |
743 | bool any = sctp_is_ep_boundall(sk); |
744 | struct sctp_endpoint *ep2; |
745 | struct list_head *list; |
746 | int cnt = 0, err = 1; |
747 | |
748 | list_for_each(list, &ep->base.bind_addr.address_list) |
749 | cnt++; |
750 | |
751 | sctp_for_each_hentry(ep2, &head->chain) { |
752 | struct sock *sk2 = ep2->base.sk; |
753 | |
754 | if (!net_eq(net1: sock_net(sk: sk2), net2: net) || sk2 == sk || |
755 | !uid_eq(left: sock_i_uid(sk: sk2), right: sock_i_uid(sk)) || |
756 | !sk2->sk_reuseport) |
757 | continue; |
758 | |
759 | err = sctp_bind_addrs_check(sp: sctp_sk(sk: sk2), |
760 | sp2: sctp_sk(sk), cnt2: cnt); |
761 | if (!err) { |
762 | err = reuseport_add_sock(sk, sk2, bind_inany: any); |
763 | if (err) |
764 | return err; |
765 | break; |
766 | } else if (err < 0) { |
767 | return err; |
768 | } |
769 | } |
770 | |
771 | if (err) { |
772 | err = reuseport_alloc(sk, bind_inany: any); |
773 | if (err) |
774 | return err; |
775 | } |
776 | } |
777 | |
778 | write_lock(&head->lock); |
779 | hlist_add_head(n: &ep->node, h: &head->chain); |
780 | write_unlock(&head->lock); |
781 | return 0; |
782 | } |
783 | |
784 | /* Add an endpoint to the hash. Local BH-safe. */ |
785 | int sctp_hash_endpoint(struct sctp_endpoint *ep) |
786 | { |
787 | int err; |
788 | |
789 | local_bh_disable(); |
790 | err = __sctp_hash_endpoint(ep); |
791 | local_bh_enable(); |
792 | |
793 | return err; |
794 | } |
795 | |
796 | /* Remove endpoint from the hash table. */ |
797 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) |
798 | { |
799 | struct sock *sk = ep->base.sk; |
800 | struct sctp_hashbucket *head; |
801 | |
802 | ep->hashent = sctp_ep_hashfn(net: sock_net(sk), lport: ep->base.bind_addr.port); |
803 | |
804 | head = &sctp_ep_hashtable[ep->hashent]; |
805 | |
806 | if (rcu_access_pointer(sk->sk_reuseport_cb)) |
807 | reuseport_detach_sock(sk); |
808 | |
809 | write_lock(&head->lock); |
810 | hlist_del_init(n: &ep->node); |
811 | write_unlock(&head->lock); |
812 | } |
813 | |
814 | /* Remove endpoint from the hash. Local BH-safe. */ |
815 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) |
816 | { |
817 | local_bh_disable(); |
818 | __sctp_unhash_endpoint(ep); |
819 | local_bh_enable(); |
820 | } |
821 | |
822 | static inline __u32 sctp_hashfn(const struct net *net, __be16 lport, |
823 | const union sctp_addr *paddr, __u32 seed) |
824 | { |
825 | __u32 addr; |
826 | |
827 | if (paddr->sa.sa_family == AF_INET6) |
828 | addr = jhash(key: &paddr->v6.sin6_addr, length: 16, initval: seed); |
829 | else |
830 | addr = (__force __u32)paddr->v4.sin_addr.s_addr; |
831 | |
832 | return jhash_3words(a: addr, b: ((__force __u32)paddr->v4.sin_port) << 16 | |
833 | (__force __u32)lport, c: net_hash_mix(net), initval: seed); |
834 | } |
835 | |
836 | /* Look up an endpoint. */ |
837 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint( |
838 | struct net *net, struct sk_buff *skb, |
839 | const union sctp_addr *laddr, |
840 | const union sctp_addr *paddr, |
841 | int dif, int sdif) |
842 | { |
843 | struct sctp_hashbucket *head; |
844 | struct sctp_endpoint *ep; |
845 | struct sock *sk; |
846 | __be16 lport; |
847 | int hash; |
848 | |
849 | lport = laddr->v4.sin_port; |
850 | hash = sctp_ep_hashfn(net, ntohs(lport)); |
851 | head = &sctp_ep_hashtable[hash]; |
852 | read_lock(&head->lock); |
853 | sctp_for_each_hentry(ep, &head->chain) { |
854 | if (sctp_endpoint_is_match(ep, net, laddr, dif, sdif)) |
855 | goto hit; |
856 | } |
857 | |
858 | ep = sctp_sk(sk: net->sctp.ctl_sock)->ep; |
859 | |
860 | hit: |
861 | sk = ep->base.sk; |
862 | if (sk->sk_reuseport) { |
863 | __u32 phash = sctp_hashfn(net, lport, paddr, seed: 0); |
864 | |
865 | sk = reuseport_select_sock(sk, hash: phash, skb, |
866 | hdr_len: sizeof(struct sctphdr)); |
867 | if (sk) |
868 | ep = sctp_sk(sk)->ep; |
869 | } |
870 | sctp_endpoint_hold(ep); |
871 | read_unlock(&head->lock); |
872 | return ep; |
873 | } |
874 | |
875 | /* rhashtable for transport */ |
876 | struct sctp_hash_cmp_arg { |
877 | const union sctp_addr *paddr; |
878 | const struct net *net; |
879 | __be16 lport; |
880 | }; |
881 | |
882 | static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg, |
883 | const void *ptr) |
884 | { |
885 | struct sctp_transport *t = (struct sctp_transport *)ptr; |
886 | const struct sctp_hash_cmp_arg *x = arg->key; |
887 | int err = 1; |
888 | |
889 | if (!sctp_cmp_addr_exact(ss1: &t->ipaddr, ss2: x->paddr)) |
890 | return err; |
891 | if (!sctp_transport_hold(t)) |
892 | return err; |
893 | |
894 | if (!net_eq(net1: t->asoc->base.net, net2: x->net)) |
895 | goto out; |
896 | if (x->lport != htons(t->asoc->base.bind_addr.port)) |
897 | goto out; |
898 | |
899 | err = 0; |
900 | out: |
901 | sctp_transport_put(t); |
902 | return err; |
903 | } |
904 | |
905 | static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed) |
906 | { |
907 | const struct sctp_transport *t = data; |
908 | |
909 | return sctp_hashfn(net: t->asoc->base.net, |
910 | htons(t->asoc->base.bind_addr.port), |
911 | paddr: &t->ipaddr, seed); |
912 | } |
913 | |
914 | static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed) |
915 | { |
916 | const struct sctp_hash_cmp_arg *x = data; |
917 | |
918 | return sctp_hashfn(net: x->net, lport: x->lport, paddr: x->paddr, seed); |
919 | } |
920 | |
921 | static const struct rhashtable_params sctp_hash_params = { |
922 | .head_offset = offsetof(struct sctp_transport, node), |
923 | .hashfn = sctp_hash_key, |
924 | .obj_hashfn = sctp_hash_obj, |
925 | .obj_cmpfn = sctp_hash_cmp, |
926 | .automatic_shrinking = true, |
927 | }; |
928 | |
929 | int sctp_transport_hashtable_init(void) |
930 | { |
931 | return rhltable_init(hlt: &sctp_transport_hashtable, params: &sctp_hash_params); |
932 | } |
933 | |
934 | void sctp_transport_hashtable_destroy(void) |
935 | { |
936 | rhltable_destroy(hlt: &sctp_transport_hashtable); |
937 | } |
938 | |
939 | int sctp_hash_transport(struct sctp_transport *t) |
940 | { |
941 | struct sctp_transport *transport; |
942 | struct rhlist_head *tmp, *list; |
943 | struct sctp_hash_cmp_arg arg; |
944 | int err; |
945 | |
946 | if (t->asoc->temp) |
947 | return 0; |
948 | |
949 | arg.net = t->asoc->base.net; |
950 | arg.paddr = &t->ipaddr; |
951 | arg.lport = htons(t->asoc->base.bind_addr.port); |
952 | |
953 | rcu_read_lock(); |
954 | list = rhltable_lookup(hlt: &sctp_transport_hashtable, key: &arg, |
955 | params: sctp_hash_params); |
956 | |
957 | rhl_for_each_entry_rcu(transport, tmp, list, node) |
958 | if (transport->asoc->ep == t->asoc->ep) { |
959 | rcu_read_unlock(); |
960 | return -EEXIST; |
961 | } |
962 | rcu_read_unlock(); |
963 | |
964 | err = rhltable_insert_key(hlt: &sctp_transport_hashtable, key: &arg, |
965 | list: &t->node, params: sctp_hash_params); |
966 | if (err) |
967 | pr_err_once("insert transport fail, errno %d\n" , err); |
968 | |
969 | return err; |
970 | } |
971 | |
972 | void sctp_unhash_transport(struct sctp_transport *t) |
973 | { |
974 | if (t->asoc->temp) |
975 | return; |
976 | |
977 | rhltable_remove(hlt: &sctp_transport_hashtable, list: &t->node, |
978 | params: sctp_hash_params); |
979 | } |
980 | |
981 | bool sctp_sk_bound_dev_eq(struct net *net, int bound_dev_if, int dif, int sdif) |
982 | { |
983 | bool l3mdev_accept = true; |
984 | |
985 | #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) |
986 | l3mdev_accept = !!READ_ONCE(net->sctp.l3mdev_accept); |
987 | #endif |
988 | return inet_bound_dev_eq(l3mdev_accept, bound_dev_if, dif, sdif); |
989 | } |
990 | |
991 | /* return a transport with holding it */ |
992 | struct sctp_transport *sctp_addrs_lookup_transport( |
993 | struct net *net, |
994 | const union sctp_addr *laddr, |
995 | const union sctp_addr *paddr, |
996 | int dif, int sdif) |
997 | { |
998 | struct rhlist_head *tmp, *list; |
999 | struct sctp_transport *t; |
1000 | int bound_dev_if; |
1001 | struct sctp_hash_cmp_arg arg = { |
1002 | .paddr = paddr, |
1003 | .net = net, |
1004 | .lport = laddr->v4.sin_port, |
1005 | }; |
1006 | |
1007 | list = rhltable_lookup(hlt: &sctp_transport_hashtable, key: &arg, |
1008 | params: sctp_hash_params); |
1009 | |
1010 | rhl_for_each_entry_rcu(t, tmp, list, node) { |
1011 | if (!sctp_transport_hold(t)) |
1012 | continue; |
1013 | |
1014 | bound_dev_if = READ_ONCE(t->asoc->base.sk->sk_bound_dev_if); |
1015 | if (sctp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif) && |
1016 | sctp_bind_addr_match(&t->asoc->base.bind_addr, |
1017 | laddr, sctp_sk(sk: t->asoc->base.sk))) |
1018 | return t; |
1019 | sctp_transport_put(t); |
1020 | } |
1021 | |
1022 | return NULL; |
1023 | } |
1024 | |
1025 | /* return a transport without holding it, as it's only used under sock lock */ |
1026 | struct sctp_transport *sctp_epaddr_lookup_transport( |
1027 | const struct sctp_endpoint *ep, |
1028 | const union sctp_addr *paddr) |
1029 | { |
1030 | struct rhlist_head *tmp, *list; |
1031 | struct sctp_transport *t; |
1032 | struct sctp_hash_cmp_arg arg = { |
1033 | .paddr = paddr, |
1034 | .net = ep->base.net, |
1035 | .lport = htons(ep->base.bind_addr.port), |
1036 | }; |
1037 | |
1038 | list = rhltable_lookup(hlt: &sctp_transport_hashtable, key: &arg, |
1039 | params: sctp_hash_params); |
1040 | |
1041 | rhl_for_each_entry_rcu(t, tmp, list, node) |
1042 | if (ep == t->asoc->ep) |
1043 | return t; |
1044 | |
1045 | return NULL; |
1046 | } |
1047 | |
1048 | /* Look up an association. */ |
1049 | static struct sctp_association *__sctp_lookup_association( |
1050 | struct net *net, |
1051 | const union sctp_addr *local, |
1052 | const union sctp_addr *peer, |
1053 | struct sctp_transport **pt, |
1054 | int dif, int sdif) |
1055 | { |
1056 | struct sctp_transport *t; |
1057 | struct sctp_association *asoc = NULL; |
1058 | |
1059 | t = sctp_addrs_lookup_transport(net, laddr: local, paddr: peer, dif, sdif); |
1060 | if (!t) |
1061 | goto out; |
1062 | |
1063 | asoc = t->asoc; |
1064 | *pt = t; |
1065 | |
1066 | out: |
1067 | return asoc; |
1068 | } |
1069 | |
1070 | /* Look up an association. protected by RCU read lock */ |
1071 | static |
1072 | struct sctp_association *sctp_lookup_association(struct net *net, |
1073 | const union sctp_addr *laddr, |
1074 | const union sctp_addr *paddr, |
1075 | struct sctp_transport **transportp, |
1076 | int dif, int sdif) |
1077 | { |
1078 | struct sctp_association *asoc; |
1079 | |
1080 | rcu_read_lock(); |
1081 | asoc = __sctp_lookup_association(net, local: laddr, peer: paddr, pt: transportp, dif, sdif); |
1082 | rcu_read_unlock(); |
1083 | |
1084 | return asoc; |
1085 | } |
1086 | |
1087 | /* Is there an association matching the given local and peer addresses? */ |
1088 | bool sctp_has_association(struct net *net, |
1089 | const union sctp_addr *laddr, |
1090 | const union sctp_addr *paddr, |
1091 | int dif, int sdif) |
1092 | { |
1093 | struct sctp_transport *transport; |
1094 | |
1095 | if (sctp_lookup_association(net, laddr, paddr, transportp: &transport, dif, sdif)) { |
1096 | sctp_transport_put(transport); |
1097 | return true; |
1098 | } |
1099 | |
1100 | return false; |
1101 | } |
1102 | |
1103 | /* |
1104 | * SCTP Implementors Guide, 2.18 Handling of address |
1105 | * parameters within the INIT or INIT-ACK. |
1106 | * |
1107 | * D) When searching for a matching TCB upon reception of an INIT |
1108 | * or INIT-ACK chunk the receiver SHOULD use not only the |
1109 | * source address of the packet (containing the INIT or |
1110 | * INIT-ACK) but the receiver SHOULD also use all valid |
1111 | * address parameters contained within the chunk. |
1112 | * |
1113 | * 2.18.3 Solution description |
1114 | * |
1115 | * This new text clearly specifies to an implementor the need |
1116 | * to look within the INIT or INIT-ACK. Any implementation that |
1117 | * does not do this, may not be able to establish associations |
1118 | * in certain circumstances. |
1119 | * |
1120 | */ |
1121 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
1122 | struct sk_buff *skb, |
1123 | const union sctp_addr *laddr, struct sctp_transport **transportp, |
1124 | int dif, int sdif) |
1125 | { |
1126 | struct sctp_association *asoc; |
1127 | union sctp_addr addr; |
1128 | union sctp_addr *paddr = &addr; |
1129 | struct sctphdr *sh = sctp_hdr(skb); |
1130 | union sctp_params params; |
1131 | struct sctp_init_chunk *init; |
1132 | struct sctp_af *af; |
1133 | |
1134 | /* |
1135 | * This code will NOT touch anything inside the chunk--it is |
1136 | * strictly READ-ONLY. |
1137 | * |
1138 | * RFC 2960 3 SCTP packet Format |
1139 | * |
1140 | * Multiple chunks can be bundled into one SCTP packet up to |
1141 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN |
1142 | * COMPLETE chunks. These chunks MUST NOT be bundled with any |
1143 | * other chunk in a packet. See Section 6.10 for more details |
1144 | * on chunk bundling. |
1145 | */ |
1146 | |
1147 | /* Find the start of the TLVs and the end of the chunk. This is |
1148 | * the region we search for address parameters. |
1149 | */ |
1150 | init = (struct sctp_init_chunk *)skb->data; |
1151 | |
1152 | /* Walk the parameters looking for embedded addresses. */ |
1153 | sctp_walk_params(params, init) { |
1154 | |
1155 | /* Note: Ignoring hostname addresses. */ |
1156 | af = sctp_get_af_specific(param_type2af(type: params.p->type)); |
1157 | if (!af) |
1158 | continue; |
1159 | |
1160 | if (!af->from_addr_param(paddr, params.addr, sh->source, 0)) |
1161 | continue; |
1162 | |
1163 | asoc = __sctp_lookup_association(net, local: laddr, peer: paddr, pt: transportp, dif, sdif); |
1164 | if (asoc) |
1165 | return asoc; |
1166 | } |
1167 | |
1168 | return NULL; |
1169 | } |
1170 | |
1171 | /* ADD-IP, Section 5.2 |
1172 | * When an endpoint receives an ASCONF Chunk from the remote peer |
1173 | * special procedures may be needed to identify the association the |
1174 | * ASCONF Chunk is associated with. To properly find the association |
1175 | * the following procedures SHOULD be followed: |
1176 | * |
1177 | * D2) If the association is not found, use the address found in the |
1178 | * Address Parameter TLV combined with the port number found in the |
1179 | * SCTP common header. If found proceed to rule D4. |
1180 | * |
1181 | * D2-ext) If more than one ASCONF Chunks are packed together, use the |
1182 | * address found in the ASCONF Address Parameter TLV of each of the |
1183 | * subsequent ASCONF Chunks. If found, proceed to rule D4. |
1184 | */ |
1185 | static struct sctp_association *__sctp_rcv_asconf_lookup( |
1186 | struct net *net, |
1187 | struct sctp_chunkhdr *ch, |
1188 | const union sctp_addr *laddr, |
1189 | __be16 peer_port, |
1190 | struct sctp_transport **transportp, |
1191 | int dif, int sdif) |
1192 | { |
1193 | struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch; |
1194 | struct sctp_af *af; |
1195 | union sctp_addr_param *param; |
1196 | union sctp_addr paddr; |
1197 | |
1198 | if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr)) |
1199 | return NULL; |
1200 | |
1201 | /* Skip over the ADDIP header and find the Address parameter */ |
1202 | param = (union sctp_addr_param *)(asconf + 1); |
1203 | |
1204 | af = sctp_get_af_specific(param_type2af(type: param->p.type)); |
1205 | if (unlikely(!af)) |
1206 | return NULL; |
1207 | |
1208 | if (!af->from_addr_param(&paddr, param, peer_port, 0)) |
1209 | return NULL; |
1210 | |
1211 | return __sctp_lookup_association(net, local: laddr, peer: &paddr, pt: transportp, dif, sdif); |
1212 | } |
1213 | |
1214 | |
1215 | /* SCTP-AUTH, Section 6.3: |
1216 | * If the receiver does not find a STCB for a packet containing an AUTH |
1217 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second |
1218 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing |
1219 | * association. |
1220 | * |
1221 | * This means that any chunks that can help us identify the association need |
1222 | * to be looked at to find this association. |
1223 | */ |
1224 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1225 | struct sk_buff *skb, |
1226 | const union sctp_addr *laddr, |
1227 | struct sctp_transport **transportp, |
1228 | int dif, int sdif) |
1229 | { |
1230 | struct sctp_association *asoc = NULL; |
1231 | struct sctp_chunkhdr *ch; |
1232 | int have_auth = 0; |
1233 | unsigned int chunk_num = 1; |
1234 | __u8 *ch_end; |
1235 | |
1236 | /* Walk through the chunks looking for AUTH or ASCONF chunks |
1237 | * to help us find the association. |
1238 | */ |
1239 | ch = (struct sctp_chunkhdr *)skb->data; |
1240 | do { |
1241 | /* Break out if chunk length is less then minimal. */ |
1242 | if (ntohs(ch->length) < sizeof(*ch)) |
1243 | break; |
1244 | |
1245 | ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); |
1246 | if (ch_end > skb_tail_pointer(skb)) |
1247 | break; |
1248 | |
1249 | switch (ch->type) { |
1250 | case SCTP_CID_AUTH: |
1251 | have_auth = chunk_num; |
1252 | break; |
1253 | |
1254 | case SCTP_CID_COOKIE_ECHO: |
1255 | /* If a packet arrives containing an AUTH chunk as |
1256 | * a first chunk, a COOKIE-ECHO chunk as the second |
1257 | * chunk, and possibly more chunks after them, and |
1258 | * the receiver does not have an STCB for that |
1259 | * packet, then authentication is based on |
1260 | * the contents of the COOKIE- ECHO chunk. |
1261 | */ |
1262 | if (have_auth == 1 && chunk_num == 2) |
1263 | return NULL; |
1264 | break; |
1265 | |
1266 | case SCTP_CID_ASCONF: |
1267 | if (have_auth || net->sctp.addip_noauth) |
1268 | asoc = __sctp_rcv_asconf_lookup( |
1269 | net, ch, laddr, |
1270 | peer_port: sctp_hdr(skb)->source, |
1271 | transportp, dif, sdif); |
1272 | break; |
1273 | default: |
1274 | break; |
1275 | } |
1276 | |
1277 | if (asoc) |
1278 | break; |
1279 | |
1280 | ch = (struct sctp_chunkhdr *)ch_end; |
1281 | chunk_num++; |
1282 | } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); |
1283 | |
1284 | return asoc; |
1285 | } |
1286 | |
1287 | /* |
1288 | * There are circumstances when we need to look inside the SCTP packet |
1289 | * for information to help us find the association. Examples |
1290 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH |
1291 | * chunks. |
1292 | */ |
1293 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1294 | struct sk_buff *skb, |
1295 | const union sctp_addr *laddr, |
1296 | struct sctp_transport **transportp, |
1297 | int dif, int sdif) |
1298 | { |
1299 | struct sctp_chunkhdr *ch; |
1300 | |
1301 | /* We do not allow GSO frames here as we need to linearize and |
1302 | * then cannot guarantee frame boundaries. This shouldn't be an |
1303 | * issue as packets hitting this are mostly INIT or INIT-ACK and |
1304 | * those cannot be on GSO-style anyway. |
1305 | */ |
1306 | if (skb_is_gso(skb) && skb_is_gso_sctp(skb)) |
1307 | return NULL; |
1308 | |
1309 | ch = (struct sctp_chunkhdr *)skb->data; |
1310 | |
1311 | /* The code below will attempt to walk the chunk and extract |
1312 | * parameter information. Before we do that, we need to verify |
1313 | * that the chunk length doesn't cause overflow. Otherwise, we'll |
1314 | * walk off the end. |
1315 | */ |
1316 | if (SCTP_PAD4(ntohs(ch->length)) > skb->len) |
1317 | return NULL; |
1318 | |
1319 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
1320 | if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
1321 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp, dif, sdif); |
1322 | |
1323 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp, dif, sdif); |
1324 | } |
1325 | |
1326 | /* Lookup an association for an inbound skb. */ |
1327 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1328 | struct sk_buff *skb, |
1329 | const union sctp_addr *paddr, |
1330 | const union sctp_addr *laddr, |
1331 | struct sctp_transport **transportp, |
1332 | int dif, int sdif) |
1333 | { |
1334 | struct sctp_association *asoc; |
1335 | |
1336 | asoc = __sctp_lookup_association(net, local: laddr, peer: paddr, pt: transportp, dif, sdif); |
1337 | if (asoc) |
1338 | goto out; |
1339 | |
1340 | /* Further lookup for INIT/INIT-ACK packets. |
1341 | * SCTP Implementors Guide, 2.18 Handling of address |
1342 | * parameters within the INIT or INIT-ACK. |
1343 | */ |
1344 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp, dif, sdif); |
1345 | if (asoc) |
1346 | goto out; |
1347 | |
1348 | if (paddr->sa.sa_family == AF_INET) |
1349 | pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n" , |
1350 | &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port), |
1351 | &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port)); |
1352 | else |
1353 | pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n" , |
1354 | &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port), |
1355 | &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port)); |
1356 | |
1357 | out: |
1358 | return asoc; |
1359 | } |
1360 | |