1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Connection tracking protocol helper module for SCTP.
4 *
5 * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
6 * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
7 *
8 * SCTP is defined in RFC 2960. References to various sections in this code
9 * are to this RFC.
10 */
11
12 #include <linux/types.h>
13 #include <linux/timer.h>
14 #include <linux/netfilter.h>
15 #include <linux/in.h>
16 #include <linux/ip.h>
17 #include <linux/sctp.h>
18 #include <linux/string.h>
19 #include <linux/seq_file.h>
20 #include <linux/spinlock.h>
21 #include <linux/interrupt.h>
22 #include <net/sctp/checksum.h>
23
24 #include <net/netfilter/nf_log.h>
25 #include <net/netfilter/nf_conntrack.h>
26 #include <net/netfilter/nf_conntrack_l4proto.h>
27 #include <net/netfilter/nf_conntrack_ecache.h>
28 #include <net/netfilter/nf_conntrack_timeout.h>
29
30 static const char *const sctp_conntrack_names[] = {
31 [SCTP_CONNTRACK_NONE] = "NONE",
32 [SCTP_CONNTRACK_CLOSED] = "CLOSED",
33 [SCTP_CONNTRACK_COOKIE_WAIT] = "COOKIE_WAIT",
34 [SCTP_CONNTRACK_COOKIE_ECHOED] = "COOKIE_ECHOED",
35 [SCTP_CONNTRACK_ESTABLISHED] = "ESTABLISHED",
36 [SCTP_CONNTRACK_SHUTDOWN_SENT] = "SHUTDOWN_SENT",
37 [SCTP_CONNTRACK_SHUTDOWN_RECD] = "SHUTDOWN_RECD",
38 [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT] = "SHUTDOWN_ACK_SENT",
39 [SCTP_CONNTRACK_HEARTBEAT_SENT] = "HEARTBEAT_SENT",
40 };
41
42 #define SECS * HZ
43 #define MINS * 60 SECS
44 #define HOURS * 60 MINS
45 #define DAYS * 24 HOURS
46
47 static const unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] = {
48 [SCTP_CONNTRACK_CLOSED] = 10 SECS,
49 [SCTP_CONNTRACK_COOKIE_WAIT] = 3 SECS,
50 [SCTP_CONNTRACK_COOKIE_ECHOED] = 3 SECS,
51 [SCTP_CONNTRACK_ESTABLISHED] = 210 SECS,
52 [SCTP_CONNTRACK_SHUTDOWN_SENT] = 3 SECS,
53 [SCTP_CONNTRACK_SHUTDOWN_RECD] = 3 SECS,
54 [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT] = 3 SECS,
55 [SCTP_CONNTRACK_HEARTBEAT_SENT] = 30 SECS,
56 };
57
58 #define SCTP_FLAG_HEARTBEAT_VTAG_FAILED 1
59
60 #define sNO SCTP_CONNTRACK_NONE
61 #define sCL SCTP_CONNTRACK_CLOSED
62 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
63 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
64 #define sES SCTP_CONNTRACK_ESTABLISHED
65 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
66 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
67 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
68 #define sHS SCTP_CONNTRACK_HEARTBEAT_SENT
69 #define sIV SCTP_CONNTRACK_MAX
70
71 /*
72 These are the descriptions of the states:
73
74 NOTE: These state names are tantalizingly similar to the states of an
75 SCTP endpoint. But the interpretation of the states is a little different,
76 considering that these are the states of the connection and not of an end
77 point. Please note the subtleties. -Kiran
78
79 NONE - Nothing so far.
80 COOKIE WAIT - We have seen an INIT chunk in the original direction, or also
81 an INIT_ACK chunk in the reply direction.
82 COOKIE ECHOED - We have seen a COOKIE_ECHO chunk in the original direction.
83 ESTABLISHED - We have seen a COOKIE_ACK in the reply direction.
84 SHUTDOWN_SENT - We have seen a SHUTDOWN chunk in the original direction.
85 SHUTDOWN_RECD - We have seen a SHUTDOWN chunk in the reply direction.
86 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
87 to that of the SHUTDOWN chunk.
88 CLOSED - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
89 the SHUTDOWN chunk. Connection is closed.
90 HEARTBEAT_SENT - We have seen a HEARTBEAT in a new flow.
91 */
92
93 /* TODO
94 - I have assumed that the first INIT is in the original direction.
95 This messes things when an INIT comes in the reply direction in CLOSED
96 state.
97 - Check the error type in the reply dir before transitioning from
98 cookie echoed to closed.
99 - Sec 5.2.4 of RFC 2960
100 - Full Multi Homing support.
101 */
102
103 /* SCTP conntrack state transitions */
104 static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
105 {
106 /* ORIGINAL */
107 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS */
108 /* init */ {sCL, sCL, sCW, sCE, sES, sCL, sCL, sSA, sCW},
109 /* init_ack */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL},
110 /* abort */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
111 /* shutdown */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA, sCL},
112 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA, sSA},
113 /* error */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sCL},/* Can't have Stale cookie*/
114 /* cookie_echo */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA, sCL},/* 5.2.4 - Big TODO */
115 /* cookie_ack */ {sCL, sCL, sCW, sES, sES, sSS, sSR, sSA, sCL},/* Can't come in orig dir */
116 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL, sCL},
117 /* heartbeat */ {sHS, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
118 /* heartbeat_ack*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
119 },
120 {
121 /* REPLY */
122 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS */
123 /* init */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sIV},/* INIT in sCL Big TODO */
124 /* init_ack */ {sIV, sCW, sCW, sCE, sES, sSS, sSR, sSA, sIV},
125 /* abort */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL, sIV},
126 /* shutdown */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA, sIV},
127 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA, sIV},
128 /* error */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA, sIV},
129 /* cookie_echo */ {sIV, sCL, sCE, sCE, sES, sSS, sSR, sSA, sIV},/* Can't come in reply dir */
130 /* cookie_ack */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA, sIV},
131 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL, sIV},
132 /* heartbeat */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sHS},
133 /* heartbeat_ack*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA, sES},
134 }
135 };
136
137 #ifdef CONFIG_NF_CONNTRACK_PROCFS
138 /* Print out the private part of the conntrack. */
sctp_print_conntrack(struct seq_file * s,struct nf_conn * ct)139 static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
140 {
141 seq_printf(s, "%s ", sctp_conntrack_names[ct->proto.sctp.state]);
142 }
143 #endif
144
145 /* do_basic_checks ensures sch->length > 0, do not use before */
146 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \
147 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \
148 (offset) < (skb)->len && \
149 ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \
150 (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
151
152 /* Some validity checks to make sure the chunks are fine */
do_basic_checks(struct nf_conn * ct,const struct sk_buff * skb,unsigned int dataoff,unsigned long * map,const struct nf_hook_state * state)153 static int do_basic_checks(struct nf_conn *ct,
154 const struct sk_buff *skb,
155 unsigned int dataoff,
156 unsigned long *map,
157 const struct nf_hook_state *state)
158 {
159 u_int32_t offset, count;
160 struct sctp_chunkhdr _sch, *sch;
161 int flag;
162
163 flag = 0;
164
165 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
166 if (sch->type == SCTP_CID_INIT ||
167 sch->type == SCTP_CID_INIT_ACK ||
168 sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
169 flag = 1;
170
171 /*
172 * Cookie Ack/Echo chunks not the first OR
173 * Init / Init Ack / Shutdown compl chunks not the only chunks
174 * OR zero-length.
175 */
176 if (((sch->type == SCTP_CID_COOKIE_ACK ||
177 sch->type == SCTP_CID_COOKIE_ECHO ||
178 flag) &&
179 count != 0) || !sch->length) {
180 nf_ct_l4proto_log_invalid(skb, ct, state,
181 "%s failed. chunk num %d, type %d, len %d flag %d\n",
182 __func__, count, sch->type, sch->length, flag);
183 return 1;
184 }
185
186 if (map)
187 set_bit(sch->type, map);
188 }
189
190 return count == 0;
191 }
192
sctp_new_state(enum ip_conntrack_dir dir,enum sctp_conntrack cur_state,int chunk_type)193 static int sctp_new_state(enum ip_conntrack_dir dir,
194 enum sctp_conntrack cur_state,
195 int chunk_type)
196 {
197 int i;
198
199 switch (chunk_type) {
200 case SCTP_CID_INIT:
201 i = 0;
202 break;
203 case SCTP_CID_INIT_ACK:
204 i = 1;
205 break;
206 case SCTP_CID_ABORT:
207 i = 2;
208 break;
209 case SCTP_CID_SHUTDOWN:
210 i = 3;
211 break;
212 case SCTP_CID_SHUTDOWN_ACK:
213 i = 4;
214 break;
215 case SCTP_CID_ERROR:
216 i = 5;
217 break;
218 case SCTP_CID_COOKIE_ECHO:
219 i = 6;
220 break;
221 case SCTP_CID_COOKIE_ACK:
222 i = 7;
223 break;
224 case SCTP_CID_SHUTDOWN_COMPLETE:
225 i = 8;
226 break;
227 case SCTP_CID_HEARTBEAT:
228 i = 9;
229 break;
230 case SCTP_CID_HEARTBEAT_ACK:
231 i = 10;
232 break;
233 default:
234 /* Other chunks like DATA or SACK do not change the state */
235 pr_debug("Unknown chunk type %d, Will stay in %s\n",
236 chunk_type, sctp_conntrack_names[cur_state]);
237 return cur_state;
238 }
239
240 return sctp_conntracks[dir][i][cur_state];
241 }
242
243 /* Don't need lock here: this conntrack not in circulation yet */
244 static noinline bool
sctp_new(struct nf_conn * ct,const struct sk_buff * skb,const struct sctphdr * sh,unsigned int dataoff)245 sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
246 const struct sctphdr *sh, unsigned int dataoff)
247 {
248 enum sctp_conntrack new_state;
249 const struct sctp_chunkhdr *sch;
250 struct sctp_chunkhdr _sch;
251 u32 offset, count;
252
253 memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
254 new_state = SCTP_CONNTRACK_MAX;
255 for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) {
256 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
257 SCTP_CONNTRACK_NONE, sch->type);
258
259 /* Invalid: delete conntrack */
260 if (new_state == SCTP_CONNTRACK_NONE ||
261 new_state == SCTP_CONNTRACK_MAX) {
262 pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
263 return false;
264 }
265
266 /* Copy the vtag into the state info */
267 if (sch->type == SCTP_CID_INIT) {
268 struct sctp_inithdr _inithdr, *ih;
269 /* Sec 8.5.1 (A) */
270 if (sh->vtag)
271 return false;
272
273 ih = skb_header_pointer(skb, offset + sizeof(_sch),
274 sizeof(_inithdr), &_inithdr);
275 if (!ih)
276 return false;
277
278 pr_debug("Setting vtag %x for new conn\n",
279 ih->init_tag);
280
281 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
282 } else if (sch->type == SCTP_CID_HEARTBEAT) {
283 pr_debug("Setting vtag %x for secondary conntrack\n",
284 sh->vtag);
285 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
286 } else if (sch->type == SCTP_CID_SHUTDOWN_ACK) {
287 /* If it is a shutdown ack OOTB packet, we expect a return
288 shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
289 pr_debug("Setting vtag %x for new conn OOTB\n",
290 sh->vtag);
291 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
292 }
293
294 ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
295 }
296
297 return true;
298 }
299
sctp_error(struct sk_buff * skb,unsigned int dataoff,const struct nf_hook_state * state)300 static bool sctp_error(struct sk_buff *skb,
301 unsigned int dataoff,
302 const struct nf_hook_state *state)
303 {
304 const struct sctphdr *sh;
305 const char *logmsg;
306
307 if (skb->len < dataoff + sizeof(struct sctphdr)) {
308 logmsg = "nf_ct_sctp: short packet ";
309 goto out_invalid;
310 }
311 if (state->hook == NF_INET_PRE_ROUTING &&
312 state->net->ct.sysctl_checksum &&
313 skb->ip_summed == CHECKSUM_NONE) {
314 if (skb_ensure_writable(skb, dataoff + sizeof(*sh))) {
315 logmsg = "nf_ct_sctp: failed to read header ";
316 goto out_invalid;
317 }
318 sh = (const struct sctphdr *)(skb->data + dataoff);
319 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
320 logmsg = "nf_ct_sctp: bad CRC ";
321 goto out_invalid;
322 }
323 skb->ip_summed = CHECKSUM_UNNECESSARY;
324 }
325 return false;
326 out_invalid:
327 nf_l4proto_log_invalid(skb, state, IPPROTO_SCTP, "%s", logmsg);
328 return true;
329 }
330
331 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
nf_conntrack_sctp_packet(struct nf_conn * ct,struct sk_buff * skb,unsigned int dataoff,enum ip_conntrack_info ctinfo,const struct nf_hook_state * state)332 int nf_conntrack_sctp_packet(struct nf_conn *ct,
333 struct sk_buff *skb,
334 unsigned int dataoff,
335 enum ip_conntrack_info ctinfo,
336 const struct nf_hook_state *state)
337 {
338 enum sctp_conntrack new_state, old_state;
339 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
340 const struct sctphdr *sh;
341 struct sctphdr _sctph;
342 const struct sctp_chunkhdr *sch;
343 struct sctp_chunkhdr _sch;
344 u_int32_t offset, count;
345 unsigned int *timeouts;
346 unsigned long map[256 / sizeof(unsigned long)] = { 0 };
347 bool ignore = false;
348
349 if (sctp_error(skb, dataoff, state))
350 return -NF_ACCEPT;
351
352 sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
353 if (sh == NULL)
354 goto out;
355
356 if (do_basic_checks(ct, skb, dataoff, map, state) != 0)
357 goto out;
358
359 if (!nf_ct_is_confirmed(ct)) {
360 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
361 if (test_bit(SCTP_CID_ABORT, map) ||
362 test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
363 test_bit(SCTP_CID_COOKIE_ACK, map))
364 return -NF_ACCEPT;
365
366 if (!sctp_new(ct, skb, sh, dataoff))
367 return -NF_ACCEPT;
368 }
369
370 /* Check the verification tag (Sec 8.5) */
371 if (!test_bit(SCTP_CID_INIT, map) &&
372 !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
373 !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
374 !test_bit(SCTP_CID_ABORT, map) &&
375 !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
376 !test_bit(SCTP_CID_HEARTBEAT, map) &&
377 !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
378 sh->vtag != ct->proto.sctp.vtag[dir]) {
379 nf_ct_l4proto_log_invalid(skb, ct, state,
380 "verification tag check failed %x vs %x for dir %d",
381 sh->vtag, ct->proto.sctp.vtag[dir], dir);
382 goto out;
383 }
384
385 old_state = new_state = SCTP_CONNTRACK_NONE;
386 spin_lock_bh(&ct->lock);
387 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
388 /* Special cases of Verification tag check (Sec 8.5.1) */
389 if (sch->type == SCTP_CID_INIT) {
390 /* (A) vtag MUST be zero */
391 if (sh->vtag != 0)
392 goto out_unlock;
393 } else if (sch->type == SCTP_CID_ABORT) {
394 /* (B) vtag MUST match own vtag if T flag is unset OR
395 * MUST match peer's vtag if T flag is set
396 */
397 if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
398 sh->vtag != ct->proto.sctp.vtag[dir]) ||
399 ((sch->flags & SCTP_CHUNK_FLAG_T) &&
400 sh->vtag != ct->proto.sctp.vtag[!dir]))
401 goto out_unlock;
402 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
403 /* (C) vtag MUST match own vtag if T flag is unset OR
404 * MUST match peer's vtag if T flag is set
405 */
406 if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
407 sh->vtag != ct->proto.sctp.vtag[dir]) ||
408 ((sch->flags & SCTP_CHUNK_FLAG_T) &&
409 sh->vtag != ct->proto.sctp.vtag[!dir]))
410 goto out_unlock;
411 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
412 /* (D) vtag must be same as init_vtag as found in INIT_ACK */
413 if (sh->vtag != ct->proto.sctp.vtag[dir])
414 goto out_unlock;
415 } else if (sch->type == SCTP_CID_COOKIE_ACK) {
416 ct->proto.sctp.init[dir] = 0;
417 ct->proto.sctp.init[!dir] = 0;
418 } else if (sch->type == SCTP_CID_HEARTBEAT) {
419 if (ct->proto.sctp.vtag[dir] == 0) {
420 pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
421 ct->proto.sctp.vtag[dir] = sh->vtag;
422 } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
423 if (test_bit(SCTP_CID_DATA, map) || ignore)
424 goto out_unlock;
425
426 ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
427 ct->proto.sctp.last_dir = dir;
428 ignore = true;
429 continue;
430 } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
431 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
432 }
433 } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
434 if (ct->proto.sctp.vtag[dir] == 0) {
435 pr_debug("Setting vtag %x for dir %d\n",
436 sh->vtag, dir);
437 ct->proto.sctp.vtag[dir] = sh->vtag;
438 } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
439 if (test_bit(SCTP_CID_DATA, map) || ignore)
440 goto out_unlock;
441
442 if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
443 ct->proto.sctp.last_dir == dir)
444 goto out_unlock;
445
446 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
447 ct->proto.sctp.vtag[dir] = sh->vtag;
448 ct->proto.sctp.vtag[!dir] = 0;
449 } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
450 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
451 }
452 }
453
454 old_state = ct->proto.sctp.state;
455 new_state = sctp_new_state(dir, old_state, sch->type);
456
457 /* Invalid */
458 if (new_state == SCTP_CONNTRACK_MAX) {
459 nf_ct_l4proto_log_invalid(skb, ct, state,
460 "Invalid, old_state %d, dir %d, type %d",
461 old_state, dir, sch->type);
462
463 goto out_unlock;
464 }
465
466 /* If it is an INIT or an INIT ACK note down the vtag */
467 if (sch->type == SCTP_CID_INIT) {
468 struct sctp_inithdr _ih, *ih;
469
470 ih = skb_header_pointer(skb, offset + sizeof(_sch), sizeof(*ih), &_ih);
471 if (!ih)
472 goto out_unlock;
473
474 if (ct->proto.sctp.init[dir] && ct->proto.sctp.init[!dir])
475 ct->proto.sctp.init[!dir] = 0;
476 ct->proto.sctp.init[dir] = 1;
477
478 pr_debug("Setting vtag %x for dir %d\n", ih->init_tag, !dir);
479 ct->proto.sctp.vtag[!dir] = ih->init_tag;
480
481 /* don't renew timeout on init retransmit so
482 * port reuse by client or NAT middlebox cannot
483 * keep entry alive indefinitely (incl. nat info).
484 */
485 if (new_state == SCTP_CONNTRACK_CLOSED &&
486 old_state == SCTP_CONNTRACK_CLOSED &&
487 nf_ct_is_confirmed(ct))
488 ignore = true;
489 } else if (sch->type == SCTP_CID_INIT_ACK) {
490 struct sctp_inithdr _ih, *ih;
491 __be32 vtag;
492
493 ih = skb_header_pointer(skb, offset + sizeof(_sch), sizeof(*ih), &_ih);
494 if (!ih)
495 goto out_unlock;
496
497 vtag = ct->proto.sctp.vtag[!dir];
498 if (!ct->proto.sctp.init[!dir] && vtag && vtag != ih->init_tag)
499 goto out_unlock;
500 /* collision */
501 if (ct->proto.sctp.init[dir] && ct->proto.sctp.init[!dir] &&
502 vtag != ih->init_tag)
503 goto out_unlock;
504
505 pr_debug("Setting vtag %x for dir %d\n", ih->init_tag, !dir);
506 ct->proto.sctp.vtag[!dir] = ih->init_tag;
507 }
508
509 ct->proto.sctp.state = new_state;
510 if (old_state != new_state) {
511 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
512 if (new_state == SCTP_CONNTRACK_ESTABLISHED &&
513 !test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
514 nf_conntrack_event_cache(IPCT_ASSURED, ct);
515 }
516 }
517 spin_unlock_bh(&ct->lock);
518
519 /* allow but do not refresh timeout */
520 if (ignore)
521 return NF_ACCEPT;
522
523 timeouts = nf_ct_timeout_lookup(ct);
524 if (!timeouts)
525 timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts;
526
527 nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
528
529 return NF_ACCEPT;
530
531 out_unlock:
532 spin_unlock_bh(&ct->lock);
533 out:
534 return -NF_ACCEPT;
535 }
536
sctp_can_early_drop(const struct nf_conn * ct)537 static bool sctp_can_early_drop(const struct nf_conn *ct)
538 {
539 switch (ct->proto.sctp.state) {
540 case SCTP_CONNTRACK_SHUTDOWN_SENT:
541 case SCTP_CONNTRACK_SHUTDOWN_RECD:
542 case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
543 return true;
544 default:
545 break;
546 }
547
548 return false;
549 }
550
551 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
552
553 #include <linux/netfilter/nfnetlink.h>
554 #include <linux/netfilter/nfnetlink_conntrack.h>
555
sctp_to_nlattr(struct sk_buff * skb,struct nlattr * nla,struct nf_conn * ct,bool destroy)556 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
557 struct nf_conn *ct, bool destroy)
558 {
559 struct nlattr *nest_parms;
560
561 spin_lock_bh(&ct->lock);
562 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP);
563 if (!nest_parms)
564 goto nla_put_failure;
565
566 if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state))
567 goto nla_put_failure;
568
569 if (destroy)
570 goto skip_state;
571
572 if (nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
573 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
574 nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
575 ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
576 goto nla_put_failure;
577
578 skip_state:
579 spin_unlock_bh(&ct->lock);
580 nla_nest_end(skb, nest_parms);
581
582 return 0;
583
584 nla_put_failure:
585 spin_unlock_bh(&ct->lock);
586 return -1;
587 }
588
589 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
590 [CTA_PROTOINFO_SCTP_STATE] = { .type = NLA_U8 },
591 [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] = { .type = NLA_U32 },
592 [CTA_PROTOINFO_SCTP_VTAG_REPLY] = { .type = NLA_U32 },
593 };
594
595 #define SCTP_NLATTR_SIZE ( \
596 NLA_ALIGN(NLA_HDRLEN + 1) + \
597 NLA_ALIGN(NLA_HDRLEN + 4) + \
598 NLA_ALIGN(NLA_HDRLEN + 4))
599
nlattr_to_sctp(struct nlattr * cda[],struct nf_conn * ct)600 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
601 {
602 struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
603 struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
604 int err;
605
606 /* updates may not contain the internal protocol info, skip parsing */
607 if (!attr)
608 return 0;
609
610 err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_SCTP_MAX, attr,
611 sctp_nla_policy, NULL);
612 if (err < 0)
613 return err;
614
615 if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
616 !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
617 !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
618 return -EINVAL;
619
620 spin_lock_bh(&ct->lock);
621 ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
622 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
623 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
624 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
625 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
626 spin_unlock_bh(&ct->lock);
627
628 return 0;
629 }
630 #endif
631
632 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
633
634 #include <linux/netfilter/nfnetlink.h>
635 #include <linux/netfilter/nfnetlink_cttimeout.h>
636
sctp_timeout_nlattr_to_obj(struct nlattr * tb[],struct net * net,void * data)637 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
638 struct net *net, void *data)
639 {
640 unsigned int *timeouts = data;
641 struct nf_sctp_net *sn = nf_sctp_pernet(net);
642 int i;
643
644 if (!timeouts)
645 timeouts = sn->timeouts;
646
647 /* set default SCTP timeouts. */
648 for (i=0; i<SCTP_CONNTRACK_MAX; i++)
649 timeouts[i] = sn->timeouts[i];
650
651 /* there's a 1:1 mapping between attributes and protocol states. */
652 for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
653 if (tb[i]) {
654 timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
655 }
656 }
657
658 timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
659 return 0;
660 }
661
662 static int
sctp_timeout_obj_to_nlattr(struct sk_buff * skb,const void * data)663 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
664 {
665 const unsigned int *timeouts = data;
666 int i;
667
668 for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
669 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
670 goto nla_put_failure;
671 }
672 return 0;
673
674 nla_put_failure:
675 return -ENOSPC;
676 }
677
678 static const struct nla_policy
679 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
680 [CTA_TIMEOUT_SCTP_CLOSED] = { .type = NLA_U32 },
681 [CTA_TIMEOUT_SCTP_COOKIE_WAIT] = { .type = NLA_U32 },
682 [CTA_TIMEOUT_SCTP_COOKIE_ECHOED] = { .type = NLA_U32 },
683 [CTA_TIMEOUT_SCTP_ESTABLISHED] = { .type = NLA_U32 },
684 [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT] = { .type = NLA_U32 },
685 [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD] = { .type = NLA_U32 },
686 [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT] = { .type = NLA_U32 },
687 [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT] = { .type = NLA_U32 },
688 [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED] = { .type = NLA_U32 },
689 };
690 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
691
nf_conntrack_sctp_init_net(struct net * net)692 void nf_conntrack_sctp_init_net(struct net *net)
693 {
694 struct nf_sctp_net *sn = nf_sctp_pernet(net);
695 int i;
696
697 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
698 sn->timeouts[i] = sctp_timeouts[i];
699
700 /* timeouts[0] is unused, init it so ->timeouts[0] contains
701 * 'new' timeout, like udp or icmp.
702 */
703 sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
704 }
705
706 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp = {
707 .l4proto = IPPROTO_SCTP,
708 #ifdef CONFIG_NF_CONNTRACK_PROCFS
709 .print_conntrack = sctp_print_conntrack,
710 #endif
711 .can_early_drop = sctp_can_early_drop,
712 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
713 .nlattr_size = SCTP_NLATTR_SIZE,
714 .to_nlattr = sctp_to_nlattr,
715 .from_nlattr = nlattr_to_sctp,
716 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
717 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
718 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
719 .nla_policy = nf_ct_port_nla_policy,
720 #endif
721 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
722 .ctnl_timeout = {
723 .nlattr_to_obj = sctp_timeout_nlattr_to_obj,
724 .obj_to_nlattr = sctp_timeout_obj_to_nlattr,
725 .nlattr_max = CTA_TIMEOUT_SCTP_MAX,
726 .obj_size = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
727 .nla_policy = sctp_timeout_nla_policy,
728 },
729 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
730 };
731