1 /*
2 * Extension Header handling for IPv6
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 * Andi Kleen <ak@muc.de>
8 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 /* Changes:
17 * yoshfuji : ensure not to overrun while parsing
18 * tlv options.
19 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
20 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
21 * handlers as inet6_protocol{}.
22 */
23
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
27 #include <linux/sockios.h>
28 #include <linux/net.h>
29 #include <linux/netdevice.h>
30 #include <linux/in6.h>
31 #include <linux/icmpv6.h>
32 #include <linux/slab.h>
33 #include <linux/export.h>
34
35 #include <net/dst.h>
36 #include <net/sock.h>
37 #include <net/snmp.h>
38
39 #include <net/ipv6.h>
40 #include <net/protocol.h>
41 #include <net/transp_v6.h>
42 #include <net/rawv6.h>
43 #include <net/ndisc.h>
44 #include <net/ip6_route.h>
45 #include <net/addrconf.h>
46 #include <net/calipso.h>
47 #if IS_ENABLED(CONFIG_IPV6_MIP6)
48 #include <net/xfrm.h>
49 #endif
50 #include <linux/seg6.h>
51 #include <net/seg6.h>
52 #ifdef CONFIG_IPV6_SEG6_HMAC
53 #include <net/seg6_hmac.h>
54 #endif
55
56 #include <linux/uaccess.h>
57
58 /*
59 * Parsing tlv encoded headers.
60 *
61 * Parsing function "func" returns true, if parsing succeed
62 * and false, if it failed.
63 * It MUST NOT touch skb->h.
64 */
65
66 struct tlvtype_proc {
67 int type;
68 bool (*func)(struct sk_buff *skb, int offset);
69 };
70
71 /*********************
72 Generic functions
73 *********************/
74
75 /* An unknown option is detected, decide what to do */
76
ip6_tlvopt_unknown(struct sk_buff * skb,int optoff)77 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
78 {
79 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
80 case 0: /* ignore */
81 return true;
82
83 case 1: /* drop packet */
84 break;
85
86 case 3: /* Send ICMP if not a multicast address and drop packet */
87 /* Actually, it is redundant check. icmp_send
88 will recheck in any case.
89 */
90 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
91 break;
92 case 2: /* send ICMP PARM PROB regardless and drop packet */
93 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
94 return false;
95 }
96
97 kfree_skb(skb);
98 return false;
99 }
100
101 /* Parse tlv encoded option header (hop-by-hop or destination) */
102
ip6_parse_tlv(const struct tlvtype_proc * procs,struct sk_buff * skb)103 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
104 {
105 const struct tlvtype_proc *curr;
106 const unsigned char *nh = skb_network_header(skb);
107 int off = skb_network_header_len(skb);
108 int len = (skb_transport_header(skb)[1] + 1) << 3;
109 int padlen = 0;
110
111 if (skb_transport_offset(skb) + len > skb_headlen(skb))
112 goto bad;
113
114 off += 2;
115 len -= 2;
116
117 while (len > 0) {
118 int optlen = nh[off + 1] + 2;
119 int i;
120
121 switch (nh[off]) {
122 case IPV6_TLV_PAD1:
123 optlen = 1;
124 padlen++;
125 if (padlen > 7)
126 goto bad;
127 break;
128
129 case IPV6_TLV_PADN:
130 /* RFC 2460 states that the purpose of PadN is
131 * to align the containing header to multiples
132 * of 8. 7 is therefore the highest valid value.
133 * See also RFC 4942, Section 2.1.9.5.
134 */
135 padlen += optlen;
136 if (padlen > 7)
137 goto bad;
138 /* RFC 4942 recommends receiving hosts to
139 * actively check PadN payload to contain
140 * only zeroes.
141 */
142 for (i = 2; i < optlen; i++) {
143 if (nh[off + i] != 0)
144 goto bad;
145 }
146 break;
147
148 default: /* Other TLV code so scan list */
149 if (optlen > len)
150 goto bad;
151 for (curr = procs; curr->type >= 0; curr++) {
152 if (curr->type == nh[off]) {
153 /* type specific length/alignment
154 checks will be performed in the
155 func(). */
156 if (curr->func(skb, off) == false)
157 return false;
158 break;
159 }
160 }
161 if (curr->type < 0) {
162 if (ip6_tlvopt_unknown(skb, off) == 0)
163 return false;
164 }
165 padlen = 0;
166 break;
167 }
168 off += optlen;
169 len -= optlen;
170 }
171
172 if (len == 0)
173 return true;
174 bad:
175 kfree_skb(skb);
176 return false;
177 }
178
179 /*****************************
180 Destination options header.
181 *****************************/
182
183 #if IS_ENABLED(CONFIG_IPV6_MIP6)
ipv6_dest_hao(struct sk_buff * skb,int optoff)184 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
185 {
186 struct ipv6_destopt_hao *hao;
187 struct inet6_skb_parm *opt = IP6CB(skb);
188 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
189 struct in6_addr tmp_addr;
190 int ret;
191
192 if (opt->dsthao) {
193 net_dbg_ratelimited("hao duplicated\n");
194 goto discard;
195 }
196 opt->dsthao = opt->dst1;
197 opt->dst1 = 0;
198
199 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
200
201 if (hao->length != 16) {
202 net_dbg_ratelimited("hao invalid option length = %d\n",
203 hao->length);
204 goto discard;
205 }
206
207 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
208 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
209 &hao->addr);
210 goto discard;
211 }
212
213 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
214 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
215 if (unlikely(ret < 0))
216 goto discard;
217
218 if (skb_cloned(skb)) {
219 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
220 goto discard;
221
222 /* update all variable using below by copied skbuff */
223 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
224 optoff);
225 ipv6h = ipv6_hdr(skb);
226 }
227
228 if (skb->ip_summed == CHECKSUM_COMPLETE)
229 skb->ip_summed = CHECKSUM_NONE;
230
231 tmp_addr = ipv6h->saddr;
232 ipv6h->saddr = hao->addr;
233 hao->addr = tmp_addr;
234
235 if (skb->tstamp == 0)
236 __net_timestamp(skb);
237
238 return true;
239
240 discard:
241 kfree_skb(skb);
242 return false;
243 }
244 #endif
245
246 static const struct tlvtype_proc tlvprocdestopt_lst[] = {
247 #if IS_ENABLED(CONFIG_IPV6_MIP6)
248 {
249 .type = IPV6_TLV_HAO,
250 .func = ipv6_dest_hao,
251 },
252 #endif
253 {-1, NULL}
254 };
255
ipv6_destopt_rcv(struct sk_buff * skb)256 static int ipv6_destopt_rcv(struct sk_buff *skb)
257 {
258 struct inet6_skb_parm *opt = IP6CB(skb);
259 #if IS_ENABLED(CONFIG_IPV6_MIP6)
260 __u16 dstbuf;
261 #endif
262 struct dst_entry *dst = skb_dst(skb);
263
264 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
265 !pskb_may_pull(skb, (skb_transport_offset(skb) +
266 ((skb_transport_header(skb)[1] + 1) << 3)))) {
267 __IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
268 IPSTATS_MIB_INHDRERRORS);
269 kfree_skb(skb);
270 return -1;
271 }
272
273 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
274 #if IS_ENABLED(CONFIG_IPV6_MIP6)
275 dstbuf = opt->dst1;
276 #endif
277
278 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
279 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
280 opt = IP6CB(skb);
281 #if IS_ENABLED(CONFIG_IPV6_MIP6)
282 opt->nhoff = dstbuf;
283 #else
284 opt->nhoff = opt->dst1;
285 #endif
286 return 1;
287 }
288
289 __IP6_INC_STATS(dev_net(dst->dev),
290 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
291 return -1;
292 }
293
seg6_update_csum(struct sk_buff * skb)294 static void seg6_update_csum(struct sk_buff *skb)
295 {
296 struct ipv6_sr_hdr *hdr;
297 struct in6_addr *addr;
298 __be32 from, to;
299
300 /* srh is at transport offset and seg_left is already decremented
301 * but daddr is not yet updated with next segment
302 */
303
304 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
305 addr = hdr->segments + hdr->segments_left;
306
307 hdr->segments_left++;
308 from = *(__be32 *)hdr;
309
310 hdr->segments_left--;
311 to = *(__be32 *)hdr;
312
313 /* update skb csum with diff resulting from seg_left decrement */
314
315 update_csum_diff4(skb, from, to);
316
317 /* compute csum diff between current and next segment and update */
318
319 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
320 (__be32 *)addr);
321 }
322
ipv6_srh_rcv(struct sk_buff * skb)323 static int ipv6_srh_rcv(struct sk_buff *skb)
324 {
325 struct inet6_skb_parm *opt = IP6CB(skb);
326 struct net *net = dev_net(skb->dev);
327 struct ipv6_sr_hdr *hdr;
328 struct inet6_dev *idev;
329 struct in6_addr *addr;
330 int accept_seg6;
331
332 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
333
334 idev = __in6_dev_get(skb->dev);
335
336 accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
337 if (accept_seg6 > idev->cnf.seg6_enabled)
338 accept_seg6 = idev->cnf.seg6_enabled;
339
340 if (!accept_seg6) {
341 kfree_skb(skb);
342 return -1;
343 }
344
345 #ifdef CONFIG_IPV6_SEG6_HMAC
346 if (!seg6_hmac_validate_skb(skb)) {
347 kfree_skb(skb);
348 return -1;
349 }
350 #endif
351
352 looped_back:
353 if (hdr->segments_left == 0) {
354 if (hdr->nexthdr == NEXTHDR_IPV6) {
355 int offset = (hdr->hdrlen + 1) << 3;
356
357 skb_postpull_rcsum(skb, skb_network_header(skb),
358 skb_network_header_len(skb));
359
360 if (!pskb_pull(skb, offset)) {
361 kfree_skb(skb);
362 return -1;
363 }
364 skb_postpull_rcsum(skb, skb_transport_header(skb),
365 offset);
366
367 skb_reset_network_header(skb);
368 skb_reset_transport_header(skb);
369 skb->encapsulation = 0;
370
371 __skb_tunnel_rx(skb, skb->dev, net);
372
373 netif_rx(skb);
374 return -1;
375 }
376
377 opt->srcrt = skb_network_header_len(skb);
378 opt->lastopt = opt->srcrt;
379 skb->transport_header += (hdr->hdrlen + 1) << 3;
380 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
381
382 return 1;
383 }
384
385 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
386 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
387 IPSTATS_MIB_INHDRERRORS);
388 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
389 ((&hdr->segments_left) -
390 skb_network_header(skb)));
391 return -1;
392 }
393
394 if (skb_cloned(skb)) {
395 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
396 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
397 IPSTATS_MIB_OUTDISCARDS);
398 kfree_skb(skb);
399 return -1;
400 }
401 }
402
403 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
404
405 hdr->segments_left--;
406 addr = hdr->segments + hdr->segments_left;
407
408 skb_push(skb, sizeof(struct ipv6hdr));
409
410 if (skb->ip_summed == CHECKSUM_COMPLETE)
411 seg6_update_csum(skb);
412
413 ipv6_hdr(skb)->daddr = *addr;
414
415 skb_dst_drop(skb);
416
417 ip6_route_input(skb);
418
419 if (skb_dst(skb)->error) {
420 dst_input(skb);
421 return -1;
422 }
423
424 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
425 if (ipv6_hdr(skb)->hop_limit <= 1) {
426 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
427 IPSTATS_MIB_INHDRERRORS);
428 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
429 ICMPV6_EXC_HOPLIMIT, 0);
430 kfree_skb(skb);
431 return -1;
432 }
433 ipv6_hdr(skb)->hop_limit--;
434
435 skb_pull(skb, sizeof(struct ipv6hdr));
436 goto looped_back;
437 }
438
439 dst_input(skb);
440
441 return -1;
442 }
443
444 /********************************
445 Routing header.
446 ********************************/
447
448 /* called with rcu_read_lock() */
ipv6_rthdr_rcv(struct sk_buff * skb)449 static int ipv6_rthdr_rcv(struct sk_buff *skb)
450 {
451 struct inet6_skb_parm *opt = IP6CB(skb);
452 struct in6_addr *addr = NULL;
453 struct in6_addr daddr;
454 struct inet6_dev *idev;
455 int n, i;
456 struct ipv6_rt_hdr *hdr;
457 struct rt0_hdr *rthdr;
458 struct net *net = dev_net(skb->dev);
459 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
460
461 idev = __in6_dev_get(skb->dev);
462 if (idev && accept_source_route > idev->cnf.accept_source_route)
463 accept_source_route = idev->cnf.accept_source_route;
464
465 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
466 !pskb_may_pull(skb, (skb_transport_offset(skb) +
467 ((skb_transport_header(skb)[1] + 1) << 3)))) {
468 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
469 IPSTATS_MIB_INHDRERRORS);
470 kfree_skb(skb);
471 return -1;
472 }
473
474 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
475
476 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
477 skb->pkt_type != PACKET_HOST) {
478 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
479 IPSTATS_MIB_INADDRERRORS);
480 kfree_skb(skb);
481 return -1;
482 }
483
484 /* segment routing */
485 if (hdr->type == IPV6_SRCRT_TYPE_4)
486 return ipv6_srh_rcv(skb);
487
488 looped_back:
489 if (hdr->segments_left == 0) {
490 switch (hdr->type) {
491 #if IS_ENABLED(CONFIG_IPV6_MIP6)
492 case IPV6_SRCRT_TYPE_2:
493 /* Silently discard type 2 header unless it was
494 * processed by own
495 */
496 if (!addr) {
497 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
498 IPSTATS_MIB_INADDRERRORS);
499 kfree_skb(skb);
500 return -1;
501 }
502 break;
503 #endif
504 default:
505 break;
506 }
507
508 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
509 skb->transport_header += (hdr->hdrlen + 1) << 3;
510 opt->dst0 = opt->dst1;
511 opt->dst1 = 0;
512 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
513 return 1;
514 }
515
516 switch (hdr->type) {
517 #if IS_ENABLED(CONFIG_IPV6_MIP6)
518 case IPV6_SRCRT_TYPE_2:
519 if (accept_source_route < 0)
520 goto unknown_rh;
521 /* Silently discard invalid RTH type 2 */
522 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
523 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
524 IPSTATS_MIB_INHDRERRORS);
525 kfree_skb(skb);
526 return -1;
527 }
528 break;
529 #endif
530 default:
531 goto unknown_rh;
532 }
533
534 /*
535 * This is the routing header forwarding algorithm from
536 * RFC 2460, page 16.
537 */
538
539 n = hdr->hdrlen >> 1;
540
541 if (hdr->segments_left > n) {
542 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
543 IPSTATS_MIB_INHDRERRORS);
544 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
545 ((&hdr->segments_left) -
546 skb_network_header(skb)));
547 return -1;
548 }
549
550 /* We are about to mangle packet header. Be careful!
551 Do not damage packets queued somewhere.
552 */
553 if (skb_cloned(skb)) {
554 /* the copy is a forwarded packet */
555 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
556 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
557 IPSTATS_MIB_OUTDISCARDS);
558 kfree_skb(skb);
559 return -1;
560 }
561 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
562 }
563
564 if (skb->ip_summed == CHECKSUM_COMPLETE)
565 skb->ip_summed = CHECKSUM_NONE;
566
567 i = n - --hdr->segments_left;
568
569 rthdr = (struct rt0_hdr *) hdr;
570 addr = rthdr->addr;
571 addr += i - 1;
572
573 switch (hdr->type) {
574 #if IS_ENABLED(CONFIG_IPV6_MIP6)
575 case IPV6_SRCRT_TYPE_2:
576 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
577 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
578 IPPROTO_ROUTING) < 0) {
579 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
580 IPSTATS_MIB_INADDRERRORS);
581 kfree_skb(skb);
582 return -1;
583 }
584 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
585 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
586 IPSTATS_MIB_INADDRERRORS);
587 kfree_skb(skb);
588 return -1;
589 }
590 break;
591 #endif
592 default:
593 break;
594 }
595
596 if (ipv6_addr_is_multicast(addr)) {
597 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
598 IPSTATS_MIB_INADDRERRORS);
599 kfree_skb(skb);
600 return -1;
601 }
602
603 daddr = *addr;
604 *addr = ipv6_hdr(skb)->daddr;
605 ipv6_hdr(skb)->daddr = daddr;
606
607 skb_dst_drop(skb);
608 ip6_route_input(skb);
609 if (skb_dst(skb)->error) {
610 skb_push(skb, skb->data - skb_network_header(skb));
611 dst_input(skb);
612 return -1;
613 }
614
615 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
616 if (ipv6_hdr(skb)->hop_limit <= 1) {
617 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
618 IPSTATS_MIB_INHDRERRORS);
619 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
620 0);
621 kfree_skb(skb);
622 return -1;
623 }
624 ipv6_hdr(skb)->hop_limit--;
625 goto looped_back;
626 }
627
628 skb_push(skb, skb->data - skb_network_header(skb));
629 dst_input(skb);
630 return -1;
631
632 unknown_rh:
633 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
634 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
635 (&hdr->type) - skb_network_header(skb));
636 return -1;
637 }
638
639 static const struct inet6_protocol rthdr_protocol = {
640 .handler = ipv6_rthdr_rcv,
641 .flags = INET6_PROTO_NOPOLICY,
642 };
643
644 static const struct inet6_protocol destopt_protocol = {
645 .handler = ipv6_destopt_rcv,
646 .flags = INET6_PROTO_NOPOLICY,
647 };
648
649 static const struct inet6_protocol nodata_protocol = {
650 .handler = dst_discard,
651 .flags = INET6_PROTO_NOPOLICY,
652 };
653
ipv6_exthdrs_init(void)654 int __init ipv6_exthdrs_init(void)
655 {
656 int ret;
657
658 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
659 if (ret)
660 goto out;
661
662 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
663 if (ret)
664 goto out_rthdr;
665
666 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
667 if (ret)
668 goto out_destopt;
669
670 out:
671 return ret;
672 out_destopt:
673 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
674 out_rthdr:
675 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
676 goto out;
677 };
678
ipv6_exthdrs_exit(void)679 void ipv6_exthdrs_exit(void)
680 {
681 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
682 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
683 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
684 }
685
686 /**********************************
687 Hop-by-hop options.
688 **********************************/
689
690 /*
691 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
692 */
ipv6_skb_idev(struct sk_buff * skb)693 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
694 {
695 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
696 }
697
ipv6_skb_net(struct sk_buff * skb)698 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
699 {
700 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
701 }
702
703 /* Router Alert as of RFC 2711 */
704
ipv6_hop_ra(struct sk_buff * skb,int optoff)705 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
706 {
707 const unsigned char *nh = skb_network_header(skb);
708
709 if (nh[optoff + 1] == 2) {
710 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
711 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
712 return true;
713 }
714 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
715 nh[optoff + 1]);
716 kfree_skb(skb);
717 return false;
718 }
719
720 /* Jumbo payload */
721
ipv6_hop_jumbo(struct sk_buff * skb,int optoff)722 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
723 {
724 const unsigned char *nh = skb_network_header(skb);
725 struct net *net = ipv6_skb_net(skb);
726 u32 pkt_len;
727
728 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
729 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
730 nh[optoff+1]);
731 __IP6_INC_STATS(net, ipv6_skb_idev(skb),
732 IPSTATS_MIB_INHDRERRORS);
733 goto drop;
734 }
735
736 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
737 if (pkt_len <= IPV6_MAXPLEN) {
738 __IP6_INC_STATS(net, ipv6_skb_idev(skb),
739 IPSTATS_MIB_INHDRERRORS);
740 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
741 return false;
742 }
743 if (ipv6_hdr(skb)->payload_len) {
744 __IP6_INC_STATS(net, ipv6_skb_idev(skb),
745 IPSTATS_MIB_INHDRERRORS);
746 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
747 return false;
748 }
749
750 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
751 __IP6_INC_STATS(net, ipv6_skb_idev(skb),
752 IPSTATS_MIB_INTRUNCATEDPKTS);
753 goto drop;
754 }
755
756 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
757 goto drop;
758
759 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
760 return true;
761
762 drop:
763 kfree_skb(skb);
764 return false;
765 }
766
767 /* CALIPSO RFC 5570 */
768
ipv6_hop_calipso(struct sk_buff * skb,int optoff)769 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
770 {
771 const unsigned char *nh = skb_network_header(skb);
772
773 if (nh[optoff + 1] < 8)
774 goto drop;
775
776 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
777 goto drop;
778
779 if (!calipso_validate(skb, nh + optoff))
780 goto drop;
781
782 return true;
783
784 drop:
785 kfree_skb(skb);
786 return false;
787 }
788
789 static const struct tlvtype_proc tlvprochopopt_lst[] = {
790 {
791 .type = IPV6_TLV_ROUTERALERT,
792 .func = ipv6_hop_ra,
793 },
794 {
795 .type = IPV6_TLV_JUMBO,
796 .func = ipv6_hop_jumbo,
797 },
798 {
799 .type = IPV6_TLV_CALIPSO,
800 .func = ipv6_hop_calipso,
801 },
802 { -1, }
803 };
804
ipv6_parse_hopopts(struct sk_buff * skb)805 int ipv6_parse_hopopts(struct sk_buff *skb)
806 {
807 struct inet6_skb_parm *opt = IP6CB(skb);
808
809 /*
810 * skb_network_header(skb) is equal to skb->data, and
811 * skb_network_header_len(skb) is always equal to
812 * sizeof(struct ipv6hdr) by definition of
813 * hop-by-hop options.
814 */
815 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
816 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
817 ((skb_transport_header(skb)[1] + 1) << 3)))) {
818 kfree_skb(skb);
819 return -1;
820 }
821
822 opt->flags |= IP6SKB_HOPBYHOP;
823 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
824 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
825 opt = IP6CB(skb);
826 opt->nhoff = sizeof(struct ipv6hdr);
827 return 1;
828 }
829 return -1;
830 }
831
832 /*
833 * Creating outbound headers.
834 *
835 * "build" functions work when skb is filled from head to tail (datagram)
836 * "push" functions work when headers are added from tail to head (tcp)
837 *
838 * In both cases we assume, that caller reserved enough room
839 * for headers.
840 */
841
ipv6_push_rthdr0(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)842 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
843 struct ipv6_rt_hdr *opt,
844 struct in6_addr **addr_p, struct in6_addr *saddr)
845 {
846 struct rt0_hdr *phdr, *ihdr;
847 int hops;
848
849 ihdr = (struct rt0_hdr *) opt;
850
851 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
852 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
853
854 hops = ihdr->rt_hdr.hdrlen >> 1;
855
856 if (hops > 1)
857 memcpy(phdr->addr, ihdr->addr + 1,
858 (hops - 1) * sizeof(struct in6_addr));
859
860 phdr->addr[hops - 1] = **addr_p;
861 *addr_p = ihdr->addr;
862
863 phdr->rt_hdr.nexthdr = *proto;
864 *proto = NEXTHDR_ROUTING;
865 }
866
ipv6_push_rthdr4(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)867 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
868 struct ipv6_rt_hdr *opt,
869 struct in6_addr **addr_p, struct in6_addr *saddr)
870 {
871 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
872 int plen, hops;
873
874 sr_ihdr = (struct ipv6_sr_hdr *)opt;
875 plen = (sr_ihdr->hdrlen + 1) << 3;
876
877 sr_phdr = skb_push(skb, plen);
878 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
879
880 hops = sr_ihdr->first_segment + 1;
881 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
882 (hops - 1) * sizeof(struct in6_addr));
883
884 sr_phdr->segments[0] = **addr_p;
885 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
886
887 if (sr_ihdr->hdrlen > hops * 2) {
888 int tlvs_offset, tlvs_length;
889
890 tlvs_offset = (1 + hops * 2) << 3;
891 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
892 memcpy((char *)sr_phdr + tlvs_offset,
893 (char *)sr_ihdr + tlvs_offset, tlvs_length);
894 }
895
896 #ifdef CONFIG_IPV6_SEG6_HMAC
897 if (sr_has_hmac(sr_phdr)) {
898 struct net *net = NULL;
899
900 if (skb->dev)
901 net = dev_net(skb->dev);
902 else if (skb->sk)
903 net = sock_net(skb->sk);
904
905 WARN_ON(!net);
906
907 if (net)
908 seg6_push_hmac(net, saddr, sr_phdr);
909 }
910 #endif
911
912 sr_phdr->nexthdr = *proto;
913 *proto = NEXTHDR_ROUTING;
914 }
915
ipv6_push_rthdr(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)916 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
917 struct ipv6_rt_hdr *opt,
918 struct in6_addr **addr_p, struct in6_addr *saddr)
919 {
920 switch (opt->type) {
921 case IPV6_SRCRT_TYPE_0:
922 case IPV6_SRCRT_STRICT:
923 case IPV6_SRCRT_TYPE_2:
924 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
925 break;
926 case IPV6_SRCRT_TYPE_4:
927 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
928 break;
929 default:
930 break;
931 }
932 }
933
ipv6_push_exthdr(struct sk_buff * skb,u8 * proto,u8 type,struct ipv6_opt_hdr * opt)934 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
935 {
936 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
937
938 memcpy(h, opt, ipv6_optlen(opt));
939 h->nexthdr = *proto;
940 *proto = type;
941 }
942
ipv6_push_nfrag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 * proto,struct in6_addr ** daddr,struct in6_addr * saddr)943 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
944 u8 *proto,
945 struct in6_addr **daddr, struct in6_addr *saddr)
946 {
947 if (opt->srcrt) {
948 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
949 /*
950 * IPV6_RTHDRDSTOPTS is ignored
951 * unless IPV6_RTHDR is set (RFC3542).
952 */
953 if (opt->dst0opt)
954 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
955 }
956 if (opt->hopopt)
957 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
958 }
959
ipv6_push_frag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 * proto)960 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
961 {
962 if (opt->dst1opt)
963 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
964 }
965 EXPORT_SYMBOL(ipv6_push_frag_opts);
966
967 struct ipv6_txoptions *
ipv6_dup_options(struct sock * sk,struct ipv6_txoptions * opt)968 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
969 {
970 struct ipv6_txoptions *opt2;
971
972 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
973 if (opt2) {
974 long dif = (char *)opt2 - (char *)opt;
975 memcpy(opt2, opt, opt->tot_len);
976 if (opt2->hopopt)
977 *((char **)&opt2->hopopt) += dif;
978 if (opt2->dst0opt)
979 *((char **)&opt2->dst0opt) += dif;
980 if (opt2->dst1opt)
981 *((char **)&opt2->dst1opt) += dif;
982 if (opt2->srcrt)
983 *((char **)&opt2->srcrt) += dif;
984 refcount_set(&opt2->refcnt, 1);
985 }
986 return opt2;
987 }
988 EXPORT_SYMBOL_GPL(ipv6_dup_options);
989
ipv6_renew_option(int renewtype,struct ipv6_opt_hdr ** dest,struct ipv6_opt_hdr * old,struct ipv6_opt_hdr * new,int newtype,char ** p)990 static void ipv6_renew_option(int renewtype,
991 struct ipv6_opt_hdr **dest,
992 struct ipv6_opt_hdr *old,
993 struct ipv6_opt_hdr *new,
994 int newtype, char **p)
995 {
996 struct ipv6_opt_hdr *src;
997
998 src = (renewtype == newtype ? new : old);
999 if (!src)
1000 return;
1001
1002 memcpy(*p, src, ipv6_optlen(src));
1003 *dest = (struct ipv6_opt_hdr *)*p;
1004 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1005 }
1006
1007 /**
1008 * ipv6_renew_options - replace a specific ext hdr with a new one.
1009 *
1010 * @sk: sock from which to allocate memory
1011 * @opt: original options
1012 * @newtype: option type to replace in @opt
1013 * @newopt: new option of type @newtype to replace (user-mem)
1014 * @newoptlen: length of @newopt
1015 *
1016 * Returns a new set of options which is a copy of @opt with the
1017 * option type @newtype replaced with @newopt.
1018 *
1019 * @opt may be NULL, in which case a new set of options is returned
1020 * containing just @newopt.
1021 *
1022 * @newopt may be NULL, in which case the specified option type is
1023 * not copied into the new set of options.
1024 *
1025 * The new set of options is allocated from the socket option memory
1026 * buffer of @sk.
1027 */
1028 struct ipv6_txoptions *
ipv6_renew_options(struct sock * sk,struct ipv6_txoptions * opt,int newtype,struct ipv6_opt_hdr * newopt)1029 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1030 int newtype, struct ipv6_opt_hdr *newopt)
1031 {
1032 int tot_len = 0;
1033 char *p;
1034 struct ipv6_txoptions *opt2;
1035
1036 if (opt) {
1037 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1038 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1039 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1040 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1041 if (newtype != IPV6_RTHDR && opt->srcrt)
1042 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1043 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1044 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1045 }
1046
1047 if (newopt)
1048 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1049
1050 if (!tot_len)
1051 return NULL;
1052
1053 tot_len += sizeof(*opt2);
1054 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1055 if (!opt2)
1056 return ERR_PTR(-ENOBUFS);
1057
1058 memset(opt2, 0, tot_len);
1059 refcount_set(&opt2->refcnt, 1);
1060 opt2->tot_len = tot_len;
1061 p = (char *)(opt2 + 1);
1062
1063 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1064 (opt ? opt->hopopt : NULL),
1065 newopt, newtype, &p);
1066 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1067 (opt ? opt->dst0opt : NULL),
1068 newopt, newtype, &p);
1069 ipv6_renew_option(IPV6_RTHDR,
1070 (struct ipv6_opt_hdr **)&opt2->srcrt,
1071 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1072 newopt, newtype, &p);
1073 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1074 (opt ? opt->dst1opt : NULL),
1075 newopt, newtype, &p);
1076
1077 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1078 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1079 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1080 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1081
1082 return opt2;
1083 }
1084
ipv6_fixup_options(struct ipv6_txoptions * opt_space,struct ipv6_txoptions * opt)1085 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1086 struct ipv6_txoptions *opt)
1087 {
1088 /*
1089 * ignore the dest before srcrt unless srcrt is being included.
1090 * --yoshfuji
1091 */
1092 if (opt && opt->dst0opt && !opt->srcrt) {
1093 if (opt_space != opt) {
1094 memcpy(opt_space, opt, sizeof(*opt_space));
1095 opt = opt_space;
1096 }
1097 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1098 opt->dst0opt = NULL;
1099 }
1100
1101 return opt;
1102 }
1103 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1104
1105 /**
1106 * fl6_update_dst - update flowi destination address with info given
1107 * by srcrt option, if any.
1108 *
1109 * @fl6: flowi6 for which daddr is to be updated
1110 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1111 * @orig: copy of original daddr address if modified
1112 *
1113 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1114 * and initial value of fl6->daddr set in orig
1115 */
fl6_update_dst(struct flowi6 * fl6,const struct ipv6_txoptions * opt,struct in6_addr * orig)1116 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1117 const struct ipv6_txoptions *opt,
1118 struct in6_addr *orig)
1119 {
1120 if (!opt || !opt->srcrt)
1121 return NULL;
1122
1123 *orig = fl6->daddr;
1124
1125 switch (opt->srcrt->type) {
1126 case IPV6_SRCRT_TYPE_0:
1127 case IPV6_SRCRT_STRICT:
1128 case IPV6_SRCRT_TYPE_2:
1129 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1130 break;
1131 case IPV6_SRCRT_TYPE_4:
1132 {
1133 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1134
1135 fl6->daddr = srh->segments[srh->segments_left];
1136 break;
1137 }
1138 default:
1139 return NULL;
1140 }
1141
1142 return orig;
1143 }
1144 EXPORT_SYMBOL_GPL(fl6_update_dst);
1145