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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#if IS_ENABLED(CONFIG_IPV6_MIP6)
47#include <net/xfrm.h>
48#endif
49
50#include <linux/uaccess.h>
51
52/*
53 * Parsing tlv encoded headers.
54 *
55 * Parsing function "func" returns true, if parsing succeed
56 * and false, if it failed.
57 * It MUST NOT touch skb->h.
58 */
59
60struct tlvtype_proc {
61 int type;
62 bool (*func)(struct sk_buff *skb, int offset);
63};
64
65/*********************
66 Generic functions
67 *********************/
68
69/* An unknown option is detected, decide what to do */
70
71static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
72{
73 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
74 case 0: /* ignore */
75 return true;
76
77 case 1: /* drop packet */
78 break;
79
80 case 3: /* Send ICMP if not a multicast address and drop packet */
81 /* Actually, it is redundant check. icmp_send
82 will recheck in any case.
83 */
84 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
85 break;
86 case 2: /* send ICMP PARM PROB regardless and drop packet */
87 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
88 return false;
89 }
90
91 kfree_skb(skb);
92 return false;
93}
94
95/* Parse tlv encoded option header (hop-by-hop or destination) */
96
97static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
98{
99 const struct tlvtype_proc *curr;
100 const unsigned char *nh = skb_network_header(skb);
101 int off = skb_network_header_len(skb);
102 int len = (skb_transport_header(skb)[1] + 1) << 3;
103 int padlen = 0;
104
105 if (skb_transport_offset(skb) + len > skb_headlen(skb))
106 goto bad;
107
108 off += 2;
109 len -= 2;
110
111 while (len > 0) {
112 int optlen = nh[off + 1] + 2;
113 int i;
114
115 switch (nh[off]) {
116 case IPV6_TLV_PAD1:
117 optlen = 1;
118 padlen++;
119 if (padlen > 7)
120 goto bad;
121 break;
122
123 case IPV6_TLV_PADN:
124 /* RFC 2460 states that the purpose of PadN is
125 * to align the containing header to multiples
126 * of 8. 7 is therefore the highest valid value.
127 * See also RFC 4942, Section 2.1.9.5.
128 */
129 padlen += optlen;
130 if (padlen > 7)
131 goto bad;
132 /* RFC 4942 recommends receiving hosts to
133 * actively check PadN payload to contain
134 * only zeroes.
135 */
136 for (i = 2; i < optlen; i++) {
137 if (nh[off + i] != 0)
138 goto bad;
139 }
140 break;
141
142 default: /* Other TLV code so scan list */
143 if (optlen > len)
144 goto bad;
145 for (curr = procs; curr->type >= 0; curr++) {
146 if (curr->type == nh[off]) {
147 /* type specific length/alignment
148 checks will be performed in the
149 func(). */
150 if (curr->func(skb, off) == false)
151 return false;
152 break;
153 }
154 }
155 if (curr->type < 0) {
156 if (ip6_tlvopt_unknown(skb, off) == 0)
157 return false;
158 }
159 padlen = 0;
160 break;
161 }
162 off += optlen;
163 len -= optlen;
164 }
165
166 if (len == 0)
167 return true;
168bad:
169 kfree_skb(skb);
170 return false;
171}
172
173/*****************************
174 Destination options header.
175 *****************************/
176
177#if IS_ENABLED(CONFIG_IPV6_MIP6)
178static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
179{
180 struct ipv6_destopt_hao *hao;
181 struct inet6_skb_parm *opt = IP6CB(skb);
182 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
183 struct in6_addr tmp_addr;
184 int ret;
185
186 if (opt->dsthao) {
187 net_dbg_ratelimited("hao duplicated\n");
188 goto discard;
189 }
190 opt->dsthao = opt->dst1;
191 opt->dst1 = 0;
192
193 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
194
195 if (hao->length != 16) {
196 net_dbg_ratelimited("hao invalid option length = %d\n",
197 hao->length);
198 goto discard;
199 }
200
201 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
202 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
203 &hao->addr);
204 goto discard;
205 }
206
207 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
208 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
209 if (unlikely(ret < 0))
210 goto discard;
211
212 if (skb_cloned(skb)) {
213 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
214 goto discard;
215
216 /* update all variable using below by copied skbuff */
217 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
218 optoff);
219 ipv6h = ipv6_hdr(skb);
220 }
221
222 if (skb->ip_summed == CHECKSUM_COMPLETE)
223 skb->ip_summed = CHECKSUM_NONE;
224
225 tmp_addr = ipv6h->saddr;
226 ipv6h->saddr = hao->addr;
227 hao->addr = tmp_addr;
228
229 if (skb->tstamp.tv64 == 0)
230 __net_timestamp(skb);
231
232 return true;
233
234 discard:
235 kfree_skb(skb);
236 return false;
237}
238#endif
239
240static const struct tlvtype_proc tlvprocdestopt_lst[] = {
241#if IS_ENABLED(CONFIG_IPV6_MIP6)
242 {
243 .type = IPV6_TLV_HAO,
244 .func = ipv6_dest_hao,
245 },
246#endif
247 {-1, NULL}
248};
249
250static int ipv6_destopt_rcv(struct sk_buff *skb)
251{
252 struct inet6_skb_parm *opt = IP6CB(skb);
253#if IS_ENABLED(CONFIG_IPV6_MIP6)
254 __u16 dstbuf;
255#endif
256 struct dst_entry *dst = skb_dst(skb);
257
258 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
259 !pskb_may_pull(skb, (skb_transport_offset(skb) +
260 ((skb_transport_header(skb)[1] + 1) << 3)))) {
261 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
262 IPSTATS_MIB_INHDRERRORS);
263 kfree_skb(skb);
264 return -1;
265 }
266
267 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
268#if IS_ENABLED(CONFIG_IPV6_MIP6)
269 dstbuf = opt->dst1;
270#endif
271
272 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
273 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
274 opt = IP6CB(skb);
275#if IS_ENABLED(CONFIG_IPV6_MIP6)
276 opt->nhoff = dstbuf;
277#else
278 opt->nhoff = opt->dst1;
279#endif
280 return 1;
281 }
282
283 IP6_INC_STATS_BH(dev_net(dst->dev),
284 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
285 return -1;
286}
287
288/********************************
289 Routing header.
290 ********************************/
291
292/* called with rcu_read_lock() */
293static int ipv6_rthdr_rcv(struct sk_buff *skb)
294{
295 struct inet6_skb_parm *opt = IP6CB(skb);
296 struct in6_addr *addr = NULL;
297 struct in6_addr daddr;
298 struct inet6_dev *idev;
299 int n, i;
300 struct ipv6_rt_hdr *hdr;
301 struct rt0_hdr *rthdr;
302 struct net *net = dev_net(skb->dev);
303 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
304
305 idev = __in6_dev_get(skb->dev);
306 if (idev && accept_source_route > idev->cnf.accept_source_route)
307 accept_source_route = idev->cnf.accept_source_route;
308
309 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
310 !pskb_may_pull(skb, (skb_transport_offset(skb) +
311 ((skb_transport_header(skb)[1] + 1) << 3)))) {
312 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
313 IPSTATS_MIB_INHDRERRORS);
314 kfree_skb(skb);
315 return -1;
316 }
317
318 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
319
320 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
321 skb->pkt_type != PACKET_HOST) {
322 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
323 IPSTATS_MIB_INADDRERRORS);
324 kfree_skb(skb);
325 return -1;
326 }
327
328looped_back:
329 if (hdr->segments_left == 0) {
330 switch (hdr->type) {
331#if IS_ENABLED(CONFIG_IPV6_MIP6)
332 case IPV6_SRCRT_TYPE_2:
333 /* Silently discard type 2 header unless it was
334 * processed by own
335 */
336 if (!addr) {
337 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
338 IPSTATS_MIB_INADDRERRORS);
339 kfree_skb(skb);
340 return -1;
341 }
342 break;
343#endif
344 default:
345 break;
346 }
347
348 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
349 skb->transport_header += (hdr->hdrlen + 1) << 3;
350 opt->dst0 = opt->dst1;
351 opt->dst1 = 0;
352 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
353 return 1;
354 }
355
356 switch (hdr->type) {
357#if IS_ENABLED(CONFIG_IPV6_MIP6)
358 case IPV6_SRCRT_TYPE_2:
359 if (accept_source_route < 0)
360 goto unknown_rh;
361 /* Silently discard invalid RTH type 2 */
362 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
363 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
364 IPSTATS_MIB_INHDRERRORS);
365 kfree_skb(skb);
366 return -1;
367 }
368 break;
369#endif
370 default:
371 goto unknown_rh;
372 }
373
374 /*
375 * This is the routing header forwarding algorithm from
376 * RFC 2460, page 16.
377 */
378
379 n = hdr->hdrlen >> 1;
380
381 if (hdr->segments_left > n) {
382 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
383 IPSTATS_MIB_INHDRERRORS);
384 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
385 ((&hdr->segments_left) -
386 skb_network_header(skb)));
387 return -1;
388 }
389
390 /* We are about to mangle packet header. Be careful!
391 Do not damage packets queued somewhere.
392 */
393 if (skb_cloned(skb)) {
394 /* the copy is a forwarded packet */
395 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
396 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
397 IPSTATS_MIB_OUTDISCARDS);
398 kfree_skb(skb);
399 return -1;
400 }
401 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
402 }
403
404 if (skb->ip_summed == CHECKSUM_COMPLETE)
405 skb->ip_summed = CHECKSUM_NONE;
406
407 i = n - --hdr->segments_left;
408
409 rthdr = (struct rt0_hdr *) hdr;
410 addr = rthdr->addr;
411 addr += i - 1;
412
413 switch (hdr->type) {
414#if IS_ENABLED(CONFIG_IPV6_MIP6)
415 case IPV6_SRCRT_TYPE_2:
416 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
417 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
418 IPPROTO_ROUTING) < 0) {
419 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
420 IPSTATS_MIB_INADDRERRORS);
421 kfree_skb(skb);
422 return -1;
423 }
424 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
425 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
426 IPSTATS_MIB_INADDRERRORS);
427 kfree_skb(skb);
428 return -1;
429 }
430 break;
431#endif
432 default:
433 break;
434 }
435
436 if (ipv6_addr_is_multicast(addr)) {
437 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
438 IPSTATS_MIB_INADDRERRORS);
439 kfree_skb(skb);
440 return -1;
441 }
442
443 daddr = *addr;
444 *addr = ipv6_hdr(skb)->daddr;
445 ipv6_hdr(skb)->daddr = daddr;
446
447 skb_dst_drop(skb);
448 ip6_route_input(skb);
449 if (skb_dst(skb)->error) {
450 skb_push(skb, skb->data - skb_network_header(skb));
451 dst_input(skb);
452 return -1;
453 }
454
455 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
456 if (ipv6_hdr(skb)->hop_limit <= 1) {
457 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
458 IPSTATS_MIB_INHDRERRORS);
459 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
460 0);
461 kfree_skb(skb);
462 return -1;
463 }
464 ipv6_hdr(skb)->hop_limit--;
465 goto looped_back;
466 }
467
468 skb_push(skb, skb->data - skb_network_header(skb));
469 dst_input(skb);
470 return -1;
471
472unknown_rh:
473 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
474 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
475 (&hdr->type) - skb_network_header(skb));
476 return -1;
477}
478
479static const struct inet6_protocol rthdr_protocol = {
480 .handler = ipv6_rthdr_rcv,
481 .flags = INET6_PROTO_NOPOLICY,
482};
483
484static const struct inet6_protocol destopt_protocol = {
485 .handler = ipv6_destopt_rcv,
486 .flags = INET6_PROTO_NOPOLICY,
487};
488
489static const struct inet6_protocol nodata_protocol = {
490 .handler = dst_discard,
491 .flags = INET6_PROTO_NOPOLICY,
492};
493
494int __init ipv6_exthdrs_init(void)
495{
496 int ret;
497
498 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
499 if (ret)
500 goto out;
501
502 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
503 if (ret)
504 goto out_rthdr;
505
506 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
507 if (ret)
508 goto out_destopt;
509
510out:
511 return ret;
512out_destopt:
513 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
514out_rthdr:
515 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
516 goto out;
517};
518
519void ipv6_exthdrs_exit(void)
520{
521 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
522 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
523 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
524}
525
526/**********************************
527 Hop-by-hop options.
528 **********************************/
529
530/*
531 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
532 */
533static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
534{
535 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
536}
537
538static inline struct net *ipv6_skb_net(struct sk_buff *skb)
539{
540 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
541}
542
543/* Router Alert as of RFC 2711 */
544
545static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
546{
547 const unsigned char *nh = skb_network_header(skb);
548
549 if (nh[optoff + 1] == 2) {
550 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
551 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
552 return true;
553 }
554 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
555 nh[optoff + 1]);
556 kfree_skb(skb);
557 return false;
558}
559
560/* Jumbo payload */
561
562static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
563{
564 const unsigned char *nh = skb_network_header(skb);
565 struct net *net = ipv6_skb_net(skb);
566 u32 pkt_len;
567
568 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
569 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
570 nh[optoff+1]);
571 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
572 IPSTATS_MIB_INHDRERRORS);
573 goto drop;
574 }
575
576 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
577 if (pkt_len <= IPV6_MAXPLEN) {
578 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
579 IPSTATS_MIB_INHDRERRORS);
580 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
581 return false;
582 }
583 if (ipv6_hdr(skb)->payload_len) {
584 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
585 IPSTATS_MIB_INHDRERRORS);
586 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
587 return false;
588 }
589
590 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
591 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
592 IPSTATS_MIB_INTRUNCATEDPKTS);
593 goto drop;
594 }
595
596 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
597 goto drop;
598
599 return true;
600
601drop:
602 kfree_skb(skb);
603 return false;
604}
605
606static const struct tlvtype_proc tlvprochopopt_lst[] = {
607 {
608 .type = IPV6_TLV_ROUTERALERT,
609 .func = ipv6_hop_ra,
610 },
611 {
612 .type = IPV6_TLV_JUMBO,
613 .func = ipv6_hop_jumbo,
614 },
615 { -1, }
616};
617
618int ipv6_parse_hopopts(struct sk_buff *skb)
619{
620 struct inet6_skb_parm *opt = IP6CB(skb);
621
622 /*
623 * skb_network_header(skb) is equal to skb->data, and
624 * skb_network_header_len(skb) is always equal to
625 * sizeof(struct ipv6hdr) by definition of
626 * hop-by-hop options.
627 */
628 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
629 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
630 ((skb_transport_header(skb)[1] + 1) << 3)))) {
631 kfree_skb(skb);
632 return -1;
633 }
634
635 opt->flags |= IP6SKB_HOPBYHOP;
636 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
637 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
638 opt = IP6CB(skb);
639 opt->nhoff = sizeof(struct ipv6hdr);
640 return 1;
641 }
642 return -1;
643}
644
645/*
646 * Creating outbound headers.
647 *
648 * "build" functions work when skb is filled from head to tail (datagram)
649 * "push" functions work when headers are added from tail to head (tcp)
650 *
651 * In both cases we assume, that caller reserved enough room
652 * for headers.
653 */
654
655static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
656 struct ipv6_rt_hdr *opt,
657 struct in6_addr **addr_p)
658{
659 struct rt0_hdr *phdr, *ihdr;
660 int hops;
661
662 ihdr = (struct rt0_hdr *) opt;
663
664 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
665 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
666
667 hops = ihdr->rt_hdr.hdrlen >> 1;
668
669 if (hops > 1)
670 memcpy(phdr->addr, ihdr->addr + 1,
671 (hops - 1) * sizeof(struct in6_addr));
672
673 phdr->addr[hops - 1] = **addr_p;
674 *addr_p = ihdr->addr;
675
676 phdr->rt_hdr.nexthdr = *proto;
677 *proto = NEXTHDR_ROUTING;
678}
679
680static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
681{
682 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
683
684 memcpy(h, opt, ipv6_optlen(opt));
685 h->nexthdr = *proto;
686 *proto = type;
687}
688
689void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
690 u8 *proto,
691 struct in6_addr **daddr)
692{
693 if (opt->srcrt) {
694 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
695 /*
696 * IPV6_RTHDRDSTOPTS is ignored
697 * unless IPV6_RTHDR is set (RFC3542).
698 */
699 if (opt->dst0opt)
700 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
701 }
702 if (opt->hopopt)
703 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
704}
705EXPORT_SYMBOL(ipv6_push_nfrag_opts);
706
707void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
708{
709 if (opt->dst1opt)
710 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
711}
712
713struct ipv6_txoptions *
714ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
715{
716 struct ipv6_txoptions *opt2;
717
718 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
719 if (opt2) {
720 long dif = (char *)opt2 - (char *)opt;
721 memcpy(opt2, opt, opt->tot_len);
722 if (opt2->hopopt)
723 *((char **)&opt2->hopopt) += dif;
724 if (opt2->dst0opt)
725 *((char **)&opt2->dst0opt) += dif;
726 if (opt2->dst1opt)
727 *((char **)&opt2->dst1opt) += dif;
728 if (opt2->srcrt)
729 *((char **)&opt2->srcrt) += dif;
730 atomic_set(&opt2->refcnt, 1);
731 }
732 return opt2;
733}
734EXPORT_SYMBOL_GPL(ipv6_dup_options);
735
736static int ipv6_renew_option(void *ohdr,
737 struct ipv6_opt_hdr __user *newopt, int newoptlen,
738 int inherit,
739 struct ipv6_opt_hdr **hdr,
740 char **p)
741{
742 if (inherit) {
743 if (ohdr) {
744 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
745 *hdr = (struct ipv6_opt_hdr *)*p;
746 *p += CMSG_ALIGN(ipv6_optlen(*hdr));
747 }
748 } else {
749 if (newopt) {
750 if (copy_from_user(*p, newopt, newoptlen))
751 return -EFAULT;
752 *hdr = (struct ipv6_opt_hdr *)*p;
753 if (ipv6_optlen(*hdr) > newoptlen)
754 return -EINVAL;
755 *p += CMSG_ALIGN(newoptlen);
756 }
757 }
758 return 0;
759}
760
761struct ipv6_txoptions *
762ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
763 int newtype,
764 struct ipv6_opt_hdr __user *newopt, int newoptlen)
765{
766 int tot_len = 0;
767 char *p;
768 struct ipv6_txoptions *opt2;
769 int err;
770
771 if (opt) {
772 if (newtype != IPV6_HOPOPTS && opt->hopopt)
773 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
774 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
775 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
776 if (newtype != IPV6_RTHDR && opt->srcrt)
777 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
778 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
779 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
780 }
781
782 if (newopt && newoptlen)
783 tot_len += CMSG_ALIGN(newoptlen);
784
785 if (!tot_len)
786 return NULL;
787
788 tot_len += sizeof(*opt2);
789 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
790 if (!opt2)
791 return ERR_PTR(-ENOBUFS);
792
793 memset(opt2, 0, tot_len);
794 atomic_set(&opt2->refcnt, 1);
795 opt2->tot_len = tot_len;
796 p = (char *)(opt2 + 1);
797
798 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
799 newtype != IPV6_HOPOPTS,
800 &opt2->hopopt, &p);
801 if (err)
802 goto out;
803
804 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
805 newtype != IPV6_RTHDRDSTOPTS,
806 &opt2->dst0opt, &p);
807 if (err)
808 goto out;
809
810 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
811 newtype != IPV6_RTHDR,
812 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
813 if (err)
814 goto out;
815
816 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
817 newtype != IPV6_DSTOPTS,
818 &opt2->dst1opt, &p);
819 if (err)
820 goto out;
821
822 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
823 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
824 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
825 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
826
827 return opt2;
828out:
829 sock_kfree_s(sk, opt2, opt2->tot_len);
830 return ERR_PTR(err);
831}
832
833struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
834 struct ipv6_txoptions *opt)
835{
836 /*
837 * ignore the dest before srcrt unless srcrt is being included.
838 * --yoshfuji
839 */
840 if (opt && opt->dst0opt && !opt->srcrt) {
841 if (opt_space != opt) {
842 memcpy(opt_space, opt, sizeof(*opt_space));
843 opt = opt_space;
844 }
845 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
846 opt->dst0opt = NULL;
847 }
848
849 return opt;
850}
851EXPORT_SYMBOL_GPL(ipv6_fixup_options);
852
853/**
854 * fl6_update_dst - update flowi destination address with info given
855 * by srcrt option, if any.
856 *
857 * @fl6: flowi6 for which daddr is to be updated
858 * @opt: struct ipv6_txoptions in which to look for srcrt opt
859 * @orig: copy of original daddr address if modified
860 *
861 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
862 * and initial value of fl6->daddr set in orig
863 */
864struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
865 const struct ipv6_txoptions *opt,
866 struct in6_addr *orig)
867{
868 if (!opt || !opt->srcrt)
869 return NULL;
870
871 *orig = fl6->daddr;
872 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
873 return orig;
874}
875EXPORT_SYMBOL_GPL(fl6_update_dst);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Extension Header handling for IPv6
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Andi Kleen <ak@muc.de>
9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
10 */
11
12/* Changes:
13 * yoshfuji : ensure not to overrun while parsing
14 * tlv options.
15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
17 * handlers as inet6_protocol{}.
18 */
19
20#include <linux/errno.h>
21#include <linux/types.h>
22#include <linux/socket.h>
23#include <linux/sockios.h>
24#include <linux/net.h>
25#include <linux/netdevice.h>
26#include <linux/in6.h>
27#include <linux/icmpv6.h>
28#include <linux/slab.h>
29#include <linux/export.h>
30
31#include <net/dst.h>
32#include <net/sock.h>
33#include <net/snmp.h>
34
35#include <net/ipv6.h>
36#include <net/protocol.h>
37#include <net/transp_v6.h>
38#include <net/rawv6.h>
39#include <net/ndisc.h>
40#include <net/ip6_route.h>
41#include <net/addrconf.h>
42#include <net/calipso.h>
43#if IS_ENABLED(CONFIG_IPV6_MIP6)
44#include <net/xfrm.h>
45#endif
46#include <linux/seg6.h>
47#include <net/seg6.h>
48#ifdef CONFIG_IPV6_SEG6_HMAC
49#include <net/seg6_hmac.h>
50#endif
51
52#include <linux/uaccess.h>
53
54/*
55 * Parsing tlv encoded headers.
56 *
57 * Parsing function "func" returns true, if parsing succeed
58 * and false, if it failed.
59 * It MUST NOT touch skb->h.
60 */
61
62struct tlvtype_proc {
63 int type;
64 bool (*func)(struct sk_buff *skb, int offset);
65};
66
67/*********************
68 Generic functions
69 *********************/
70
71/* An unknown option is detected, decide what to do */
72
73static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
74 bool disallow_unknowns)
75{
76 if (disallow_unknowns) {
77 /* If unknown TLVs are disallowed by configuration
78 * then always silently drop packet. Note this also
79 * means no ICMP parameter problem is sent which
80 * could be a good property to mitigate a reflection DOS
81 * attack.
82 */
83
84 goto drop;
85 }
86
87 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
88 case 0: /* ignore */
89 return true;
90
91 case 1: /* drop packet */
92 break;
93
94 case 3: /* Send ICMP if not a multicast address and drop packet */
95 /* Actually, it is redundant check. icmp_send
96 will recheck in any case.
97 */
98 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
99 break;
100 /* fall through */
101 case 2: /* send ICMP PARM PROB regardless and drop packet */
102 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
103 return false;
104 }
105
106drop:
107 kfree_skb(skb);
108 return false;
109}
110
111/* Parse tlv encoded option header (hop-by-hop or destination) */
112
113static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
114 struct sk_buff *skb,
115 int max_count)
116{
117 int len = (skb_transport_header(skb)[1] + 1) << 3;
118 const unsigned char *nh = skb_network_header(skb);
119 int off = skb_network_header_len(skb);
120 const struct tlvtype_proc *curr;
121 bool disallow_unknowns = false;
122 int tlv_count = 0;
123 int padlen = 0;
124
125 if (unlikely(max_count < 0)) {
126 disallow_unknowns = true;
127 max_count = -max_count;
128 }
129
130 if (skb_transport_offset(skb) + len > skb_headlen(skb))
131 goto bad;
132
133 off += 2;
134 len -= 2;
135
136 while (len > 0) {
137 int optlen = nh[off + 1] + 2;
138 int i;
139
140 switch (nh[off]) {
141 case IPV6_TLV_PAD1:
142 optlen = 1;
143 padlen++;
144 if (padlen > 7)
145 goto bad;
146 break;
147
148 case IPV6_TLV_PADN:
149 /* RFC 2460 states that the purpose of PadN is
150 * to align the containing header to multiples
151 * of 8. 7 is therefore the highest valid value.
152 * See also RFC 4942, Section 2.1.9.5.
153 */
154 padlen += optlen;
155 if (padlen > 7)
156 goto bad;
157 /* RFC 4942 recommends receiving hosts to
158 * actively check PadN payload to contain
159 * only zeroes.
160 */
161 for (i = 2; i < optlen; i++) {
162 if (nh[off + i] != 0)
163 goto bad;
164 }
165 break;
166
167 default: /* Other TLV code so scan list */
168 if (optlen > len)
169 goto bad;
170
171 tlv_count++;
172 if (tlv_count > max_count)
173 goto bad;
174
175 for (curr = procs; curr->type >= 0; curr++) {
176 if (curr->type == nh[off]) {
177 /* type specific length/alignment
178 checks will be performed in the
179 func(). */
180 if (curr->func(skb, off) == false)
181 return false;
182 break;
183 }
184 }
185 if (curr->type < 0 &&
186 !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
187 return false;
188
189 padlen = 0;
190 break;
191 }
192 off += optlen;
193 len -= optlen;
194 }
195
196 if (len == 0)
197 return true;
198bad:
199 kfree_skb(skb);
200 return false;
201}
202
203/*****************************
204 Destination options header.
205 *****************************/
206
207#if IS_ENABLED(CONFIG_IPV6_MIP6)
208static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
209{
210 struct ipv6_destopt_hao *hao;
211 struct inet6_skb_parm *opt = IP6CB(skb);
212 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
213 int ret;
214
215 if (opt->dsthao) {
216 net_dbg_ratelimited("hao duplicated\n");
217 goto discard;
218 }
219 opt->dsthao = opt->dst1;
220 opt->dst1 = 0;
221
222 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
223
224 if (hao->length != 16) {
225 net_dbg_ratelimited("hao invalid option length = %d\n",
226 hao->length);
227 goto discard;
228 }
229
230 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
231 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
232 &hao->addr);
233 goto discard;
234 }
235
236 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
237 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
238 if (unlikely(ret < 0))
239 goto discard;
240
241 if (skb_cloned(skb)) {
242 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
243 goto discard;
244
245 /* update all variable using below by copied skbuff */
246 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
247 optoff);
248 ipv6h = ipv6_hdr(skb);
249 }
250
251 if (skb->ip_summed == CHECKSUM_COMPLETE)
252 skb->ip_summed = CHECKSUM_NONE;
253
254 swap(ipv6h->saddr, hao->addr);
255
256 if (skb->tstamp == 0)
257 __net_timestamp(skb);
258
259 return true;
260
261 discard:
262 kfree_skb(skb);
263 return false;
264}
265#endif
266
267static const struct tlvtype_proc tlvprocdestopt_lst[] = {
268#if IS_ENABLED(CONFIG_IPV6_MIP6)
269 {
270 .type = IPV6_TLV_HAO,
271 .func = ipv6_dest_hao,
272 },
273#endif
274 {-1, NULL}
275};
276
277static int ipv6_destopt_rcv(struct sk_buff *skb)
278{
279 struct inet6_dev *idev = __in6_dev_get(skb->dev);
280 struct inet6_skb_parm *opt = IP6CB(skb);
281#if IS_ENABLED(CONFIG_IPV6_MIP6)
282 __u16 dstbuf;
283#endif
284 struct dst_entry *dst = skb_dst(skb);
285 struct net *net = dev_net(skb->dev);
286 int extlen;
287
288 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
289 !pskb_may_pull(skb, (skb_transport_offset(skb) +
290 ((skb_transport_header(skb)[1] + 1) << 3)))) {
291 __IP6_INC_STATS(dev_net(dst->dev), idev,
292 IPSTATS_MIB_INHDRERRORS);
293fail_and_free:
294 kfree_skb(skb);
295 return -1;
296 }
297
298 extlen = (skb_transport_header(skb)[1] + 1) << 3;
299 if (extlen > net->ipv6.sysctl.max_dst_opts_len)
300 goto fail_and_free;
301
302 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
303#if IS_ENABLED(CONFIG_IPV6_MIP6)
304 dstbuf = opt->dst1;
305#endif
306
307 if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
308 init_net.ipv6.sysctl.max_dst_opts_cnt)) {
309 skb->transport_header += extlen;
310 opt = IP6CB(skb);
311#if IS_ENABLED(CONFIG_IPV6_MIP6)
312 opt->nhoff = dstbuf;
313#else
314 opt->nhoff = opt->dst1;
315#endif
316 return 1;
317 }
318
319 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
320 return -1;
321}
322
323static void seg6_update_csum(struct sk_buff *skb)
324{
325 struct ipv6_sr_hdr *hdr;
326 struct in6_addr *addr;
327 __be32 from, to;
328
329 /* srh is at transport offset and seg_left is already decremented
330 * but daddr is not yet updated with next segment
331 */
332
333 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
334 addr = hdr->segments + hdr->segments_left;
335
336 hdr->segments_left++;
337 from = *(__be32 *)hdr;
338
339 hdr->segments_left--;
340 to = *(__be32 *)hdr;
341
342 /* update skb csum with diff resulting from seg_left decrement */
343
344 update_csum_diff4(skb, from, to);
345
346 /* compute csum diff between current and next segment and update */
347
348 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
349 (__be32 *)addr);
350}
351
352static int ipv6_srh_rcv(struct sk_buff *skb)
353{
354 struct inet6_skb_parm *opt = IP6CB(skb);
355 struct net *net = dev_net(skb->dev);
356 struct ipv6_sr_hdr *hdr;
357 struct inet6_dev *idev;
358 struct in6_addr *addr;
359 int accept_seg6;
360
361 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
362
363 idev = __in6_dev_get(skb->dev);
364
365 accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
366 if (accept_seg6 > idev->cnf.seg6_enabled)
367 accept_seg6 = idev->cnf.seg6_enabled;
368
369 if (!accept_seg6) {
370 kfree_skb(skb);
371 return -1;
372 }
373
374#ifdef CONFIG_IPV6_SEG6_HMAC
375 if (!seg6_hmac_validate_skb(skb)) {
376 kfree_skb(skb);
377 return -1;
378 }
379#endif
380
381looped_back:
382 if (hdr->segments_left == 0) {
383 if (hdr->nexthdr == NEXTHDR_IPV6) {
384 int offset = (hdr->hdrlen + 1) << 3;
385
386 skb_postpull_rcsum(skb, skb_network_header(skb),
387 skb_network_header_len(skb));
388
389 if (!pskb_pull(skb, offset)) {
390 kfree_skb(skb);
391 return -1;
392 }
393 skb_postpull_rcsum(skb, skb_transport_header(skb),
394 offset);
395
396 skb_reset_network_header(skb);
397 skb_reset_transport_header(skb);
398 skb->encapsulation = 0;
399
400 __skb_tunnel_rx(skb, skb->dev, net);
401
402 netif_rx(skb);
403 return -1;
404 }
405
406 opt->srcrt = skb_network_header_len(skb);
407 opt->lastopt = opt->srcrt;
408 skb->transport_header += (hdr->hdrlen + 1) << 3;
409 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
410
411 return 1;
412 }
413
414 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
415 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
416 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
417 ((&hdr->segments_left) -
418 skb_network_header(skb)));
419 return -1;
420 }
421
422 if (skb_cloned(skb)) {
423 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
424 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
425 IPSTATS_MIB_OUTDISCARDS);
426 kfree_skb(skb);
427 return -1;
428 }
429 }
430
431 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
432
433 hdr->segments_left--;
434 addr = hdr->segments + hdr->segments_left;
435
436 skb_push(skb, sizeof(struct ipv6hdr));
437
438 if (skb->ip_summed == CHECKSUM_COMPLETE)
439 seg6_update_csum(skb);
440
441 ipv6_hdr(skb)->daddr = *addr;
442
443 skb_dst_drop(skb);
444
445 ip6_route_input(skb);
446
447 if (skb_dst(skb)->error) {
448 dst_input(skb);
449 return -1;
450 }
451
452 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
453 if (ipv6_hdr(skb)->hop_limit <= 1) {
454 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
455 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
456 ICMPV6_EXC_HOPLIMIT, 0);
457 kfree_skb(skb);
458 return -1;
459 }
460 ipv6_hdr(skb)->hop_limit--;
461
462 skb_pull(skb, sizeof(struct ipv6hdr));
463 goto looped_back;
464 }
465
466 dst_input(skb);
467
468 return -1;
469}
470
471/********************************
472 Routing header.
473 ********************************/
474
475/* called with rcu_read_lock() */
476static int ipv6_rthdr_rcv(struct sk_buff *skb)
477{
478 struct inet6_dev *idev = __in6_dev_get(skb->dev);
479 struct inet6_skb_parm *opt = IP6CB(skb);
480 struct in6_addr *addr = NULL;
481 struct in6_addr daddr;
482 int n, i;
483 struct ipv6_rt_hdr *hdr;
484 struct rt0_hdr *rthdr;
485 struct net *net = dev_net(skb->dev);
486 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
487
488 idev = __in6_dev_get(skb->dev);
489 if (idev && accept_source_route > idev->cnf.accept_source_route)
490 accept_source_route = idev->cnf.accept_source_route;
491
492 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
493 !pskb_may_pull(skb, (skb_transport_offset(skb) +
494 ((skb_transport_header(skb)[1] + 1) << 3)))) {
495 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
496 kfree_skb(skb);
497 return -1;
498 }
499
500 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
501
502 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
503 skb->pkt_type != PACKET_HOST) {
504 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
505 kfree_skb(skb);
506 return -1;
507 }
508
509 /* segment routing */
510 if (hdr->type == IPV6_SRCRT_TYPE_4)
511 return ipv6_srh_rcv(skb);
512
513looped_back:
514 if (hdr->segments_left == 0) {
515 switch (hdr->type) {
516#if IS_ENABLED(CONFIG_IPV6_MIP6)
517 case IPV6_SRCRT_TYPE_2:
518 /* Silently discard type 2 header unless it was
519 * processed by own
520 */
521 if (!addr) {
522 __IP6_INC_STATS(net, idev,
523 IPSTATS_MIB_INADDRERRORS);
524 kfree_skb(skb);
525 return -1;
526 }
527 break;
528#endif
529 default:
530 break;
531 }
532
533 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
534 skb->transport_header += (hdr->hdrlen + 1) << 3;
535 opt->dst0 = opt->dst1;
536 opt->dst1 = 0;
537 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
538 return 1;
539 }
540
541 switch (hdr->type) {
542#if IS_ENABLED(CONFIG_IPV6_MIP6)
543 case IPV6_SRCRT_TYPE_2:
544 if (accept_source_route < 0)
545 goto unknown_rh;
546 /* Silently discard invalid RTH type 2 */
547 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
548 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
549 kfree_skb(skb);
550 return -1;
551 }
552 break;
553#endif
554 default:
555 goto unknown_rh;
556 }
557
558 /*
559 * This is the routing header forwarding algorithm from
560 * RFC 2460, page 16.
561 */
562
563 n = hdr->hdrlen >> 1;
564
565 if (hdr->segments_left > n) {
566 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
567 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
568 ((&hdr->segments_left) -
569 skb_network_header(skb)));
570 return -1;
571 }
572
573 /* We are about to mangle packet header. Be careful!
574 Do not damage packets queued somewhere.
575 */
576 if (skb_cloned(skb)) {
577 /* the copy is a forwarded packet */
578 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
579 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
580 IPSTATS_MIB_OUTDISCARDS);
581 kfree_skb(skb);
582 return -1;
583 }
584 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
585 }
586
587 if (skb->ip_summed == CHECKSUM_COMPLETE)
588 skb->ip_summed = CHECKSUM_NONE;
589
590 i = n - --hdr->segments_left;
591
592 rthdr = (struct rt0_hdr *) hdr;
593 addr = rthdr->addr;
594 addr += i - 1;
595
596 switch (hdr->type) {
597#if IS_ENABLED(CONFIG_IPV6_MIP6)
598 case IPV6_SRCRT_TYPE_2:
599 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
600 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
601 IPPROTO_ROUTING) < 0) {
602 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
603 kfree_skb(skb);
604 return -1;
605 }
606 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
607 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
608 kfree_skb(skb);
609 return -1;
610 }
611 break;
612#endif
613 default:
614 break;
615 }
616
617 if (ipv6_addr_is_multicast(addr)) {
618 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
619 kfree_skb(skb);
620 return -1;
621 }
622
623 daddr = *addr;
624 *addr = ipv6_hdr(skb)->daddr;
625 ipv6_hdr(skb)->daddr = daddr;
626
627 skb_dst_drop(skb);
628 ip6_route_input(skb);
629 if (skb_dst(skb)->error) {
630 skb_push(skb, skb->data - skb_network_header(skb));
631 dst_input(skb);
632 return -1;
633 }
634
635 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
636 if (ipv6_hdr(skb)->hop_limit <= 1) {
637 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
638 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
639 0);
640 kfree_skb(skb);
641 return -1;
642 }
643 ipv6_hdr(skb)->hop_limit--;
644 goto looped_back;
645 }
646
647 skb_push(skb, skb->data - skb_network_header(skb));
648 dst_input(skb);
649 return -1;
650
651unknown_rh:
652 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
653 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
654 (&hdr->type) - skb_network_header(skb));
655 return -1;
656}
657
658static const struct inet6_protocol rthdr_protocol = {
659 .handler = ipv6_rthdr_rcv,
660 .flags = INET6_PROTO_NOPOLICY,
661};
662
663static const struct inet6_protocol destopt_protocol = {
664 .handler = ipv6_destopt_rcv,
665 .flags = INET6_PROTO_NOPOLICY,
666};
667
668static const struct inet6_protocol nodata_protocol = {
669 .handler = dst_discard,
670 .flags = INET6_PROTO_NOPOLICY,
671};
672
673int __init ipv6_exthdrs_init(void)
674{
675 int ret;
676
677 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
678 if (ret)
679 goto out;
680
681 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
682 if (ret)
683 goto out_rthdr;
684
685 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
686 if (ret)
687 goto out_destopt;
688
689out:
690 return ret;
691out_destopt:
692 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
693out_rthdr:
694 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
695 goto out;
696};
697
698void ipv6_exthdrs_exit(void)
699{
700 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
701 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
702 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
703}
704
705/**********************************
706 Hop-by-hop options.
707 **********************************/
708
709/*
710 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
711 */
712static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
713{
714 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
715}
716
717static inline struct net *ipv6_skb_net(struct sk_buff *skb)
718{
719 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
720}
721
722/* Router Alert as of RFC 2711 */
723
724static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
725{
726 const unsigned char *nh = skb_network_header(skb);
727
728 if (nh[optoff + 1] == 2) {
729 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
730 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
731 return true;
732 }
733 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
734 nh[optoff + 1]);
735 kfree_skb(skb);
736 return false;
737}
738
739/* Jumbo payload */
740
741static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
742{
743 const unsigned char *nh = skb_network_header(skb);
744 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
745 struct net *net = ipv6_skb_net(skb);
746 u32 pkt_len;
747
748 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
749 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
750 nh[optoff+1]);
751 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
752 goto drop;
753 }
754
755 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
756 if (pkt_len <= IPV6_MAXPLEN) {
757 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
758 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
759 return false;
760 }
761 if (ipv6_hdr(skb)->payload_len) {
762 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
763 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
764 return false;
765 }
766
767 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
768 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
769 goto drop;
770 }
771
772 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
773 goto drop;
774
775 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
776 return true;
777
778drop:
779 kfree_skb(skb);
780 return false;
781}
782
783/* CALIPSO RFC 5570 */
784
785static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
786{
787 const unsigned char *nh = skb_network_header(skb);
788
789 if (nh[optoff + 1] < 8)
790 goto drop;
791
792 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
793 goto drop;
794
795 if (!calipso_validate(skb, nh + optoff))
796 goto drop;
797
798 return true;
799
800drop:
801 kfree_skb(skb);
802 return false;
803}
804
805static const struct tlvtype_proc tlvprochopopt_lst[] = {
806 {
807 .type = IPV6_TLV_ROUTERALERT,
808 .func = ipv6_hop_ra,
809 },
810 {
811 .type = IPV6_TLV_JUMBO,
812 .func = ipv6_hop_jumbo,
813 },
814 {
815 .type = IPV6_TLV_CALIPSO,
816 .func = ipv6_hop_calipso,
817 },
818 { -1, }
819};
820
821int ipv6_parse_hopopts(struct sk_buff *skb)
822{
823 struct inet6_skb_parm *opt = IP6CB(skb);
824 struct net *net = dev_net(skb->dev);
825 int extlen;
826
827 /*
828 * skb_network_header(skb) is equal to skb->data, and
829 * skb_network_header_len(skb) is always equal to
830 * sizeof(struct ipv6hdr) by definition of
831 * hop-by-hop options.
832 */
833 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
834 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
835 ((skb_transport_header(skb)[1] + 1) << 3)))) {
836fail_and_free:
837 kfree_skb(skb);
838 return -1;
839 }
840
841 extlen = (skb_transport_header(skb)[1] + 1) << 3;
842 if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
843 goto fail_and_free;
844
845 opt->flags |= IP6SKB_HOPBYHOP;
846 if (ip6_parse_tlv(tlvprochopopt_lst, skb,
847 init_net.ipv6.sysctl.max_hbh_opts_cnt)) {
848 skb->transport_header += extlen;
849 opt = IP6CB(skb);
850 opt->nhoff = sizeof(struct ipv6hdr);
851 return 1;
852 }
853 return -1;
854}
855
856/*
857 * Creating outbound headers.
858 *
859 * "build" functions work when skb is filled from head to tail (datagram)
860 * "push" functions work when headers are added from tail to head (tcp)
861 *
862 * In both cases we assume, that caller reserved enough room
863 * for headers.
864 */
865
866static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
867 struct ipv6_rt_hdr *opt,
868 struct in6_addr **addr_p, struct in6_addr *saddr)
869{
870 struct rt0_hdr *phdr, *ihdr;
871 int hops;
872
873 ihdr = (struct rt0_hdr *) opt;
874
875 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
876 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
877
878 hops = ihdr->rt_hdr.hdrlen >> 1;
879
880 if (hops > 1)
881 memcpy(phdr->addr, ihdr->addr + 1,
882 (hops - 1) * sizeof(struct in6_addr));
883
884 phdr->addr[hops - 1] = **addr_p;
885 *addr_p = ihdr->addr;
886
887 phdr->rt_hdr.nexthdr = *proto;
888 *proto = NEXTHDR_ROUTING;
889}
890
891static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
892 struct ipv6_rt_hdr *opt,
893 struct in6_addr **addr_p, struct in6_addr *saddr)
894{
895 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
896 int plen, hops;
897
898 sr_ihdr = (struct ipv6_sr_hdr *)opt;
899 plen = (sr_ihdr->hdrlen + 1) << 3;
900
901 sr_phdr = skb_push(skb, plen);
902 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
903
904 hops = sr_ihdr->first_segment + 1;
905 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
906 (hops - 1) * sizeof(struct in6_addr));
907
908 sr_phdr->segments[0] = **addr_p;
909 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
910
911 if (sr_ihdr->hdrlen > hops * 2) {
912 int tlvs_offset, tlvs_length;
913
914 tlvs_offset = (1 + hops * 2) << 3;
915 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
916 memcpy((char *)sr_phdr + tlvs_offset,
917 (char *)sr_ihdr + tlvs_offset, tlvs_length);
918 }
919
920#ifdef CONFIG_IPV6_SEG6_HMAC
921 if (sr_has_hmac(sr_phdr)) {
922 struct net *net = NULL;
923
924 if (skb->dev)
925 net = dev_net(skb->dev);
926 else if (skb->sk)
927 net = sock_net(skb->sk);
928
929 WARN_ON(!net);
930
931 if (net)
932 seg6_push_hmac(net, saddr, sr_phdr);
933 }
934#endif
935
936 sr_phdr->nexthdr = *proto;
937 *proto = NEXTHDR_ROUTING;
938}
939
940static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
941 struct ipv6_rt_hdr *opt,
942 struct in6_addr **addr_p, struct in6_addr *saddr)
943{
944 switch (opt->type) {
945 case IPV6_SRCRT_TYPE_0:
946 case IPV6_SRCRT_STRICT:
947 case IPV6_SRCRT_TYPE_2:
948 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
949 break;
950 case IPV6_SRCRT_TYPE_4:
951 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
952 break;
953 default:
954 break;
955 }
956}
957
958static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
959{
960 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
961
962 memcpy(h, opt, ipv6_optlen(opt));
963 h->nexthdr = *proto;
964 *proto = type;
965}
966
967void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
968 u8 *proto,
969 struct in6_addr **daddr, struct in6_addr *saddr)
970{
971 if (opt->srcrt) {
972 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
973 /*
974 * IPV6_RTHDRDSTOPTS is ignored
975 * unless IPV6_RTHDR is set (RFC3542).
976 */
977 if (opt->dst0opt)
978 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
979 }
980 if (opt->hopopt)
981 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
982}
983
984void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
985{
986 if (opt->dst1opt)
987 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
988}
989EXPORT_SYMBOL(ipv6_push_frag_opts);
990
991struct ipv6_txoptions *
992ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
993{
994 struct ipv6_txoptions *opt2;
995
996 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
997 if (opt2) {
998 long dif = (char *)opt2 - (char *)opt;
999 memcpy(opt2, opt, opt->tot_len);
1000 if (opt2->hopopt)
1001 *((char **)&opt2->hopopt) += dif;
1002 if (opt2->dst0opt)
1003 *((char **)&opt2->dst0opt) += dif;
1004 if (opt2->dst1opt)
1005 *((char **)&opt2->dst1opt) += dif;
1006 if (opt2->srcrt)
1007 *((char **)&opt2->srcrt) += dif;
1008 refcount_set(&opt2->refcnt, 1);
1009 }
1010 return opt2;
1011}
1012EXPORT_SYMBOL_GPL(ipv6_dup_options);
1013
1014static void ipv6_renew_option(int renewtype,
1015 struct ipv6_opt_hdr **dest,
1016 struct ipv6_opt_hdr *old,
1017 struct ipv6_opt_hdr *new,
1018 int newtype, char **p)
1019{
1020 struct ipv6_opt_hdr *src;
1021
1022 src = (renewtype == newtype ? new : old);
1023 if (!src)
1024 return;
1025
1026 memcpy(*p, src, ipv6_optlen(src));
1027 *dest = (struct ipv6_opt_hdr *)*p;
1028 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1029}
1030
1031/**
1032 * ipv6_renew_options - replace a specific ext hdr with a new one.
1033 *
1034 * @sk: sock from which to allocate memory
1035 * @opt: original options
1036 * @newtype: option type to replace in @opt
1037 * @newopt: new option of type @newtype to replace (user-mem)
1038 * @newoptlen: length of @newopt
1039 *
1040 * Returns a new set of options which is a copy of @opt with the
1041 * option type @newtype replaced with @newopt.
1042 *
1043 * @opt may be NULL, in which case a new set of options is returned
1044 * containing just @newopt.
1045 *
1046 * @newopt may be NULL, in which case the specified option type is
1047 * not copied into the new set of options.
1048 *
1049 * The new set of options is allocated from the socket option memory
1050 * buffer of @sk.
1051 */
1052struct ipv6_txoptions *
1053ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1054 int newtype, struct ipv6_opt_hdr *newopt)
1055{
1056 int tot_len = 0;
1057 char *p;
1058 struct ipv6_txoptions *opt2;
1059
1060 if (opt) {
1061 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1062 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1063 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1064 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1065 if (newtype != IPV6_RTHDR && opt->srcrt)
1066 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1067 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1068 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1069 }
1070
1071 if (newopt)
1072 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1073
1074 if (!tot_len)
1075 return NULL;
1076
1077 tot_len += sizeof(*opt2);
1078 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1079 if (!opt2)
1080 return ERR_PTR(-ENOBUFS);
1081
1082 memset(opt2, 0, tot_len);
1083 refcount_set(&opt2->refcnt, 1);
1084 opt2->tot_len = tot_len;
1085 p = (char *)(opt2 + 1);
1086
1087 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1088 (opt ? opt->hopopt : NULL),
1089 newopt, newtype, &p);
1090 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1091 (opt ? opt->dst0opt : NULL),
1092 newopt, newtype, &p);
1093 ipv6_renew_option(IPV6_RTHDR,
1094 (struct ipv6_opt_hdr **)&opt2->srcrt,
1095 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1096 newopt, newtype, &p);
1097 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1098 (opt ? opt->dst1opt : NULL),
1099 newopt, newtype, &p);
1100
1101 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1102 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1103 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1104 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1105
1106 return opt2;
1107}
1108
1109struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1110 struct ipv6_txoptions *opt)
1111{
1112 /*
1113 * ignore the dest before srcrt unless srcrt is being included.
1114 * --yoshfuji
1115 */
1116 if (opt && opt->dst0opt && !opt->srcrt) {
1117 if (opt_space != opt) {
1118 memcpy(opt_space, opt, sizeof(*opt_space));
1119 opt = opt_space;
1120 }
1121 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1122 opt->dst0opt = NULL;
1123 }
1124
1125 return opt;
1126}
1127EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1128
1129/**
1130 * fl6_update_dst - update flowi destination address with info given
1131 * by srcrt option, if any.
1132 *
1133 * @fl6: flowi6 for which daddr is to be updated
1134 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1135 * @orig: copy of original daddr address if modified
1136 *
1137 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1138 * and initial value of fl6->daddr set in orig
1139 */
1140struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1141 const struct ipv6_txoptions *opt,
1142 struct in6_addr *orig)
1143{
1144 if (!opt || !opt->srcrt)
1145 return NULL;
1146
1147 *orig = fl6->daddr;
1148
1149 switch (opt->srcrt->type) {
1150 case IPV6_SRCRT_TYPE_0:
1151 case IPV6_SRCRT_STRICT:
1152 case IPV6_SRCRT_TYPE_2:
1153 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1154 break;
1155 case IPV6_SRCRT_TYPE_4:
1156 {
1157 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1158
1159 fl6->daddr = srh->segments[srh->segments_left];
1160 break;
1161 }
1162 default:
1163 return NULL;
1164 }
1165
1166 return orig;
1167}
1168EXPORT_SYMBOL_GPL(fl6_update_dst);