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] = 300 SECS / 1000,
53 [SCTP_CONNTRACK_SHUTDOWN_RECD] = 300 SECS / 1000,
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 directoin.
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, sSS, sSR, 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, sCE, 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, sCW, 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 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \
146 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \
147 (offset) < (skb)->len && \
148 ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \
149 (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
150
151 /* 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)152 static int do_basic_checks(struct nf_conn *ct,
153 const struct sk_buff *skb,
154 unsigned int dataoff,
155 unsigned long *map)
156 {
157 u_int32_t offset, count;
158 struct sctp_chunkhdr _sch, *sch;
159 int flag;
160
161 flag = 0;
162
163 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
164 pr_debug("Chunk Num: %d Type: %d\n", count, sch->type);
165
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 pr_debug("Basic checks failed\n");
181 return 1;
182 }
183
184 if (map)
185 set_bit(sch->type, map);
186 }
187
188 pr_debug("Basic checks passed\n");
189 return count == 0;
190 }
191
sctp_new_state(enum ip_conntrack_dir dir,enum sctp_conntrack cur_state,int chunk_type)192 static int sctp_new_state(enum ip_conntrack_dir dir,
193 enum sctp_conntrack cur_state,
194 int chunk_type)
195 {
196 int i;
197
198 pr_debug("Chunk type: %d\n", chunk_type);
199
200 switch (chunk_type) {
201 case SCTP_CID_INIT:
202 pr_debug("SCTP_CID_INIT\n");
203 i = 0;
204 break;
205 case SCTP_CID_INIT_ACK:
206 pr_debug("SCTP_CID_INIT_ACK\n");
207 i = 1;
208 break;
209 case SCTP_CID_ABORT:
210 pr_debug("SCTP_CID_ABORT\n");
211 i = 2;
212 break;
213 case SCTP_CID_SHUTDOWN:
214 pr_debug("SCTP_CID_SHUTDOWN\n");
215 i = 3;
216 break;
217 case SCTP_CID_SHUTDOWN_ACK:
218 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
219 i = 4;
220 break;
221 case SCTP_CID_ERROR:
222 pr_debug("SCTP_CID_ERROR\n");
223 i = 5;
224 break;
225 case SCTP_CID_COOKIE_ECHO:
226 pr_debug("SCTP_CID_COOKIE_ECHO\n");
227 i = 6;
228 break;
229 case SCTP_CID_COOKIE_ACK:
230 pr_debug("SCTP_CID_COOKIE_ACK\n");
231 i = 7;
232 break;
233 case SCTP_CID_SHUTDOWN_COMPLETE:
234 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
235 i = 8;
236 break;
237 case SCTP_CID_HEARTBEAT:
238 pr_debug("SCTP_CID_HEARTBEAT");
239 i = 9;
240 break;
241 case SCTP_CID_HEARTBEAT_ACK:
242 pr_debug("SCTP_CID_HEARTBEAT_ACK");
243 i = 10;
244 break;
245 default:
246 /* Other chunks like DATA or SACK do not change the state */
247 pr_debug("Unknown chunk type, Will stay in %s\n",
248 sctp_conntrack_names[cur_state]);
249 return cur_state;
250 }
251
252 pr_debug("dir: %d cur_state: %s chunk_type: %d new_state: %s\n",
253 dir, sctp_conntrack_names[cur_state], chunk_type,
254 sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
255
256 return sctp_conntracks[dir][i][cur_state];
257 }
258
259 /* Don't need lock here: this conntrack not in circulation yet */
260 static noinline bool
sctp_new(struct nf_conn * ct,const struct sk_buff * skb,const struct sctphdr * sh,unsigned int dataoff)261 sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
262 const struct sctphdr *sh, unsigned int dataoff)
263 {
264 enum sctp_conntrack new_state;
265 const struct sctp_chunkhdr *sch;
266 struct sctp_chunkhdr _sch;
267 u32 offset, count;
268
269 memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
270 new_state = SCTP_CONNTRACK_MAX;
271 for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) {
272 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
273 SCTP_CONNTRACK_NONE, sch->type);
274
275 /* Invalid: delete conntrack */
276 if (new_state == SCTP_CONNTRACK_NONE ||
277 new_state == SCTP_CONNTRACK_MAX) {
278 pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
279 return false;
280 }
281
282 /* Copy the vtag into the state info */
283 if (sch->type == SCTP_CID_INIT) {
284 struct sctp_inithdr _inithdr, *ih;
285 /* Sec 8.5.1 (A) */
286 if (sh->vtag)
287 return false;
288
289 ih = skb_header_pointer(skb, offset + sizeof(_sch),
290 sizeof(_inithdr), &_inithdr);
291 if (!ih)
292 return false;
293
294 pr_debug("Setting vtag %x for new conn\n",
295 ih->init_tag);
296
297 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = ih->init_tag;
298 } else if (sch->type == SCTP_CID_HEARTBEAT) {
299 pr_debug("Setting vtag %x for secondary conntrack\n",
300 sh->vtag);
301 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] = sh->vtag;
302 } else {
303 /* If it is a shutdown ack OOTB packet, we expect a return
304 shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
305 pr_debug("Setting vtag %x for new conn OOTB\n",
306 sh->vtag);
307 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
308 }
309
310 ct->proto.sctp.state = SCTP_CONNTRACK_NONE;
311 }
312
313 return true;
314 }
315
sctp_error(struct sk_buff * skb,unsigned int dataoff,const struct nf_hook_state * state)316 static bool sctp_error(struct sk_buff *skb,
317 unsigned int dataoff,
318 const struct nf_hook_state *state)
319 {
320 const struct sctphdr *sh;
321 const char *logmsg;
322
323 if (skb->len < dataoff + sizeof(struct sctphdr)) {
324 logmsg = "nf_ct_sctp: short packet ";
325 goto out_invalid;
326 }
327 if (state->hook == NF_INET_PRE_ROUTING &&
328 state->net->ct.sysctl_checksum &&
329 skb->ip_summed == CHECKSUM_NONE) {
330 if (skb_ensure_writable(skb, dataoff + sizeof(*sh))) {
331 logmsg = "nf_ct_sctp: failed to read header ";
332 goto out_invalid;
333 }
334 sh = (const struct sctphdr *)(skb->data + dataoff);
335 if (sh->checksum != sctp_compute_cksum(skb, dataoff)) {
336 logmsg = "nf_ct_sctp: bad CRC ";
337 goto out_invalid;
338 }
339 skb->ip_summed = CHECKSUM_UNNECESSARY;
340 }
341 return false;
342 out_invalid:
343 nf_l4proto_log_invalid(skb, state, IPPROTO_SCTP, "%s", logmsg);
344 return true;
345 }
346
347 /* 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)348 int nf_conntrack_sctp_packet(struct nf_conn *ct,
349 struct sk_buff *skb,
350 unsigned int dataoff,
351 enum ip_conntrack_info ctinfo,
352 const struct nf_hook_state *state)
353 {
354 enum sctp_conntrack new_state, old_state;
355 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
356 const struct sctphdr *sh;
357 struct sctphdr _sctph;
358 const struct sctp_chunkhdr *sch;
359 struct sctp_chunkhdr _sch;
360 u_int32_t offset, count;
361 unsigned int *timeouts;
362 unsigned long map[256 / sizeof(unsigned long)] = { 0 };
363 bool ignore = false;
364
365 if (sctp_error(skb, dataoff, state))
366 return -NF_ACCEPT;
367
368 sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
369 if (sh == NULL)
370 goto out;
371
372 if (do_basic_checks(ct, skb, dataoff, map) != 0)
373 goto out;
374
375 if (!nf_ct_is_confirmed(ct)) {
376 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
377 if (test_bit(SCTP_CID_ABORT, map) ||
378 test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
379 test_bit(SCTP_CID_COOKIE_ACK, map))
380 return -NF_ACCEPT;
381
382 if (!sctp_new(ct, skb, sh, dataoff))
383 return -NF_ACCEPT;
384 }
385
386 /* Check the verification tag (Sec 8.5) */
387 if (!test_bit(SCTP_CID_INIT, map) &&
388 !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
389 !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
390 !test_bit(SCTP_CID_ABORT, map) &&
391 !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
392 !test_bit(SCTP_CID_HEARTBEAT, map) &&
393 !test_bit(SCTP_CID_HEARTBEAT_ACK, map) &&
394 sh->vtag != ct->proto.sctp.vtag[dir]) {
395 pr_debug("Verification tag check failed\n");
396 goto out;
397 }
398
399 old_state = new_state = SCTP_CONNTRACK_NONE;
400 spin_lock_bh(&ct->lock);
401 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
402 /* Special cases of Verification tag check (Sec 8.5.1) */
403 if (sch->type == SCTP_CID_INIT) {
404 /* (A) vtag MUST be zero */
405 if (sh->vtag != 0)
406 goto out_unlock;
407 } else if (sch->type == SCTP_CID_ABORT) {
408 /* (B) vtag MUST match own vtag if T flag is unset OR
409 * MUST match peer's vtag if T flag is set
410 */
411 if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
412 sh->vtag != ct->proto.sctp.vtag[dir]) ||
413 ((sch->flags & SCTP_CHUNK_FLAG_T) &&
414 sh->vtag != ct->proto.sctp.vtag[!dir]))
415 goto out_unlock;
416 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
417 /* (C) vtag MUST match own vtag if T flag is unset OR
418 * MUST match peer's vtag if T flag is set
419 */
420 if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
421 sh->vtag != ct->proto.sctp.vtag[dir]) ||
422 ((sch->flags & SCTP_CHUNK_FLAG_T) &&
423 sh->vtag != ct->proto.sctp.vtag[!dir]))
424 goto out_unlock;
425 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
426 /* (D) vtag must be same as init_vtag as found in INIT_ACK */
427 if (sh->vtag != ct->proto.sctp.vtag[dir])
428 goto out_unlock;
429 } else if (sch->type == SCTP_CID_HEARTBEAT) {
430 if (ct->proto.sctp.vtag[dir] == 0) {
431 pr_debug("Setting %d vtag %x for dir %d\n", sch->type, sh->vtag, dir);
432 ct->proto.sctp.vtag[dir] = sh->vtag;
433 } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
434 if (test_bit(SCTP_CID_DATA, map) || ignore)
435 goto out_unlock;
436
437 ct->proto.sctp.flags |= SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
438 ct->proto.sctp.last_dir = dir;
439 ignore = true;
440 continue;
441 } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
442 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
443 }
444 } else if (sch->type == SCTP_CID_HEARTBEAT_ACK) {
445 if (ct->proto.sctp.vtag[dir] == 0) {
446 pr_debug("Setting vtag %x for dir %d\n",
447 sh->vtag, dir);
448 ct->proto.sctp.vtag[dir] = sh->vtag;
449 } else if (sh->vtag != ct->proto.sctp.vtag[dir]) {
450 if (test_bit(SCTP_CID_DATA, map) || ignore)
451 goto out_unlock;
452
453 if ((ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) == 0 ||
454 ct->proto.sctp.last_dir == dir)
455 goto out_unlock;
456
457 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
458 ct->proto.sctp.vtag[dir] = sh->vtag;
459 ct->proto.sctp.vtag[!dir] = 0;
460 } else if (ct->proto.sctp.flags & SCTP_FLAG_HEARTBEAT_VTAG_FAILED) {
461 ct->proto.sctp.flags &= ~SCTP_FLAG_HEARTBEAT_VTAG_FAILED;
462 }
463 }
464
465 old_state = ct->proto.sctp.state;
466 new_state = sctp_new_state(dir, old_state, sch->type);
467
468 /* Invalid */
469 if (new_state == SCTP_CONNTRACK_MAX) {
470 pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
471 "conntrack=%u\n",
472 dir, sch->type, old_state);
473 goto out_unlock;
474 }
475
476 /* If it is an INIT or an INIT ACK note down the vtag */
477 if (sch->type == SCTP_CID_INIT ||
478 sch->type == SCTP_CID_INIT_ACK) {
479 struct sctp_inithdr _inithdr, *ih;
480
481 ih = skb_header_pointer(skb, offset + sizeof(_sch),
482 sizeof(_inithdr), &_inithdr);
483 if (ih == NULL)
484 goto out_unlock;
485 pr_debug("Setting vtag %x for dir %d\n",
486 ih->init_tag, !dir);
487 ct->proto.sctp.vtag[!dir] = ih->init_tag;
488
489 /* don't renew timeout on init retransmit so
490 * port reuse by client or NAT middlebox cannot
491 * keep entry alive indefinitely (incl. nat info).
492 */
493 if (new_state == SCTP_CONNTRACK_CLOSED &&
494 old_state == SCTP_CONNTRACK_CLOSED &&
495 nf_ct_is_confirmed(ct))
496 ignore = true;
497 }
498
499 ct->proto.sctp.state = new_state;
500 if (old_state != new_state) {
501 nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
502 if (new_state == SCTP_CONNTRACK_ESTABLISHED &&
503 !test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
504 nf_conntrack_event_cache(IPCT_ASSURED, ct);
505 }
506 }
507 spin_unlock_bh(&ct->lock);
508
509 /* allow but do not refresh timeout */
510 if (ignore)
511 return NF_ACCEPT;
512
513 timeouts = nf_ct_timeout_lookup(ct);
514 if (!timeouts)
515 timeouts = nf_sctp_pernet(nf_ct_net(ct))->timeouts;
516
517 nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
518
519 return NF_ACCEPT;
520
521 out_unlock:
522 spin_unlock_bh(&ct->lock);
523 out:
524 return -NF_ACCEPT;
525 }
526
sctp_can_early_drop(const struct nf_conn * ct)527 static bool sctp_can_early_drop(const struct nf_conn *ct)
528 {
529 switch (ct->proto.sctp.state) {
530 case SCTP_CONNTRACK_SHUTDOWN_SENT:
531 case SCTP_CONNTRACK_SHUTDOWN_RECD:
532 case SCTP_CONNTRACK_SHUTDOWN_ACK_SENT:
533 return true;
534 default:
535 break;
536 }
537
538 return false;
539 }
540
541 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
542
543 #include <linux/netfilter/nfnetlink.h>
544 #include <linux/netfilter/nfnetlink_conntrack.h>
545
sctp_to_nlattr(struct sk_buff * skb,struct nlattr * nla,struct nf_conn * ct,bool destroy)546 static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
547 struct nf_conn *ct, bool destroy)
548 {
549 struct nlattr *nest_parms;
550
551 spin_lock_bh(&ct->lock);
552 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP);
553 if (!nest_parms)
554 goto nla_put_failure;
555
556 if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state))
557 goto nla_put_failure;
558
559 if (destroy)
560 goto skip_state;
561
562 if (nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
563 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
564 nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
565 ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
566 goto nla_put_failure;
567
568 skip_state:
569 spin_unlock_bh(&ct->lock);
570 nla_nest_end(skb, nest_parms);
571
572 return 0;
573
574 nla_put_failure:
575 spin_unlock_bh(&ct->lock);
576 return -1;
577 }
578
579 static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
580 [CTA_PROTOINFO_SCTP_STATE] = { .type = NLA_U8 },
581 [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] = { .type = NLA_U32 },
582 [CTA_PROTOINFO_SCTP_VTAG_REPLY] = { .type = NLA_U32 },
583 };
584
585 #define SCTP_NLATTR_SIZE ( \
586 NLA_ALIGN(NLA_HDRLEN + 1) + \
587 NLA_ALIGN(NLA_HDRLEN + 4) + \
588 NLA_ALIGN(NLA_HDRLEN + 4))
589
nlattr_to_sctp(struct nlattr * cda[],struct nf_conn * ct)590 static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
591 {
592 struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
593 struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
594 int err;
595
596 /* updates may not contain the internal protocol info, skip parsing */
597 if (!attr)
598 return 0;
599
600 err = nla_parse_nested_deprecated(tb, CTA_PROTOINFO_SCTP_MAX, attr,
601 sctp_nla_policy, NULL);
602 if (err < 0)
603 return err;
604
605 if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
606 !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
607 !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
608 return -EINVAL;
609
610 spin_lock_bh(&ct->lock);
611 ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
612 ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
613 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
614 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
615 nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
616 spin_unlock_bh(&ct->lock);
617
618 return 0;
619 }
620 #endif
621
622 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
623
624 #include <linux/netfilter/nfnetlink.h>
625 #include <linux/netfilter/nfnetlink_cttimeout.h>
626
sctp_timeout_nlattr_to_obj(struct nlattr * tb[],struct net * net,void * data)627 static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
628 struct net *net, void *data)
629 {
630 unsigned int *timeouts = data;
631 struct nf_sctp_net *sn = nf_sctp_pernet(net);
632 int i;
633
634 if (!timeouts)
635 timeouts = sn->timeouts;
636
637 /* set default SCTP timeouts. */
638 for (i=0; i<SCTP_CONNTRACK_MAX; i++)
639 timeouts[i] = sn->timeouts[i];
640
641 /* there's a 1:1 mapping between attributes and protocol states. */
642 for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
643 if (tb[i]) {
644 timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
645 }
646 }
647
648 timeouts[CTA_TIMEOUT_SCTP_UNSPEC] = timeouts[CTA_TIMEOUT_SCTP_CLOSED];
649 return 0;
650 }
651
652 static int
sctp_timeout_obj_to_nlattr(struct sk_buff * skb,const void * data)653 sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
654 {
655 const unsigned int *timeouts = data;
656 int i;
657
658 for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
659 if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
660 goto nla_put_failure;
661 }
662 return 0;
663
664 nla_put_failure:
665 return -ENOSPC;
666 }
667
668 static const struct nla_policy
669 sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
670 [CTA_TIMEOUT_SCTP_CLOSED] = { .type = NLA_U32 },
671 [CTA_TIMEOUT_SCTP_COOKIE_WAIT] = { .type = NLA_U32 },
672 [CTA_TIMEOUT_SCTP_COOKIE_ECHOED] = { .type = NLA_U32 },
673 [CTA_TIMEOUT_SCTP_ESTABLISHED] = { .type = NLA_U32 },
674 [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT] = { .type = NLA_U32 },
675 [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD] = { .type = NLA_U32 },
676 [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT] = { .type = NLA_U32 },
677 [CTA_TIMEOUT_SCTP_HEARTBEAT_SENT] = { .type = NLA_U32 },
678 [CTA_TIMEOUT_SCTP_HEARTBEAT_ACKED] = { .type = NLA_U32 },
679 };
680 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
681
nf_conntrack_sctp_init_net(struct net * net)682 void nf_conntrack_sctp_init_net(struct net *net)
683 {
684 struct nf_sctp_net *sn = nf_sctp_pernet(net);
685 int i;
686
687 for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
688 sn->timeouts[i] = sctp_timeouts[i];
689
690 /* timeouts[0] is unused, init it so ->timeouts[0] contains
691 * 'new' timeout, like udp or icmp.
692 */
693 sn->timeouts[0] = sctp_timeouts[SCTP_CONNTRACK_CLOSED];
694 }
695
696 const struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp = {
697 .l4proto = IPPROTO_SCTP,
698 #ifdef CONFIG_NF_CONNTRACK_PROCFS
699 .print_conntrack = sctp_print_conntrack,
700 #endif
701 .can_early_drop = sctp_can_early_drop,
702 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
703 .nlattr_size = SCTP_NLATTR_SIZE,
704 .to_nlattr = sctp_to_nlattr,
705 .from_nlattr = nlattr_to_sctp,
706 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
707 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
708 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
709 .nla_policy = nf_ct_port_nla_policy,
710 #endif
711 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
712 .ctnl_timeout = {
713 .nlattr_to_obj = sctp_timeout_nlattr_to_obj,
714 .obj_to_nlattr = sctp_timeout_obj_to_nlattr,
715 .nlattr_max = CTA_TIMEOUT_SCTP_MAX,
716 .obj_size = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
717 .nla_policy = sctp_timeout_nla_policy,
718 },
719 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
720 };
721