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1/*
2 * Internet Control Message Protocol (ICMPv6)
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * Based on net/ipv4/icmp.c
9 *
10 * RFC 1885
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17
18/*
19 * Changes:
20 *
21 * Andi Kleen : exception handling
22 * Andi Kleen add rate limits. never reply to a icmp.
23 * add more length checks and other fixes.
24 * yoshfuji : ensure to sent parameter problem for
25 * fragments.
26 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
27 * Randy Dunlap and
28 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
29 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
30 */
31
32#define pr_fmt(fmt) "IPv6: " fmt
33
34#include <linux/module.h>
35#include <linux/errno.h>
36#include <linux/types.h>
37#include <linux/socket.h>
38#include <linux/in.h>
39#include <linux/kernel.h>
40#include <linux/sockios.h>
41#include <linux/net.h>
42#include <linux/skbuff.h>
43#include <linux/init.h>
44#include <linux/netfilter.h>
45#include <linux/slab.h>
46
47#ifdef CONFIG_SYSCTL
48#include <linux/sysctl.h>
49#endif
50
51#include <linux/inet.h>
52#include <linux/netdevice.h>
53#include <linux/icmpv6.h>
54
55#include <net/ip.h>
56#include <net/sock.h>
57
58#include <net/ipv6.h>
59#include <net/ip6_checksum.h>
60#include <net/ping.h>
61#include <net/protocol.h>
62#include <net/raw.h>
63#include <net/rawv6.h>
64#include <net/transp_v6.h>
65#include <net/ip6_route.h>
66#include <net/addrconf.h>
67#include <net/icmp.h>
68#include <net/xfrm.h>
69#include <net/inet_common.h>
70#include <net/dsfield.h>
71#include <net/l3mdev.h>
72
73#include <linux/uaccess.h>
74
75/*
76 * The ICMP socket(s). This is the most convenient way to flow control
77 * our ICMP output as well as maintain a clean interface throughout
78 * all layers. All Socketless IP sends will soon be gone.
79 *
80 * On SMP we have one ICMP socket per-cpu.
81 */
82static inline struct sock *icmpv6_sk(struct net *net)
83{
84 return net->ipv6.icmp_sk[smp_processor_id()];
85}
86
87static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
88 u8 type, u8 code, int offset, __be32 info)
89{
90 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
91 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
92 struct net *net = dev_net(skb->dev);
93
94 if (type == ICMPV6_PKT_TOOBIG)
95 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
96 else if (type == NDISC_REDIRECT)
97 ip6_redirect(skb, net, skb->dev->ifindex, 0,
98 sock_net_uid(net, NULL));
99
100 if (!(type & ICMPV6_INFOMSG_MASK))
101 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
102 ping_err(skb, offset, ntohl(info));
103}
104
105static int icmpv6_rcv(struct sk_buff *skb);
106
107static const struct inet6_protocol icmpv6_protocol = {
108 .handler = icmpv6_rcv,
109 .err_handler = icmpv6_err,
110 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
111};
112
113/* Called with BH disabled */
114static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
115{
116 struct sock *sk;
117
118 sk = icmpv6_sk(net);
119 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
120 /* This can happen if the output path (f.e. SIT or
121 * ip6ip6 tunnel) signals dst_link_failure() for an
122 * outgoing ICMP6 packet.
123 */
124 return NULL;
125 }
126 return sk;
127}
128
129static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
130{
131 spin_unlock(&sk->sk_lock.slock);
132}
133
134/*
135 * Figure out, may we reply to this packet with icmp error.
136 *
137 * We do not reply, if:
138 * - it was icmp error message.
139 * - it is truncated, so that it is known, that protocol is ICMPV6
140 * (i.e. in the middle of some exthdr)
141 *
142 * --ANK (980726)
143 */
144
145static bool is_ineligible(const struct sk_buff *skb)
146{
147 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
148 int len = skb->len - ptr;
149 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
150 __be16 frag_off;
151
152 if (len < 0)
153 return true;
154
155 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
156 if (ptr < 0)
157 return false;
158 if (nexthdr == IPPROTO_ICMPV6) {
159 u8 _type, *tp;
160 tp = skb_header_pointer(skb,
161 ptr+offsetof(struct icmp6hdr, icmp6_type),
162 sizeof(_type), &_type);
163 if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
164 return true;
165 }
166 return false;
167}
168
169static bool icmpv6_mask_allow(int type)
170{
171 /* Informational messages are not limited. */
172 if (type & ICMPV6_INFOMSG_MASK)
173 return true;
174
175 /* Do not limit pmtu discovery, it would break it. */
176 if (type == ICMPV6_PKT_TOOBIG)
177 return true;
178
179 return false;
180}
181
182static bool icmpv6_global_allow(int type)
183{
184 if (icmpv6_mask_allow(type))
185 return true;
186
187 if (icmp_global_allow())
188 return true;
189
190 return false;
191}
192
193/*
194 * Check the ICMP output rate limit
195 */
196static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
197 struct flowi6 *fl6)
198{
199 struct net *net = sock_net(sk);
200 struct dst_entry *dst;
201 bool res = false;
202
203 if (icmpv6_mask_allow(type))
204 return true;
205
206 /*
207 * Look up the output route.
208 * XXX: perhaps the expire for routing entries cloned by
209 * this lookup should be more aggressive (not longer than timeout).
210 */
211 dst = ip6_route_output(net, sk, fl6);
212 if (dst->error) {
213 IP6_INC_STATS(net, ip6_dst_idev(dst),
214 IPSTATS_MIB_OUTNOROUTES);
215 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
216 res = true;
217 } else {
218 struct rt6_info *rt = (struct rt6_info *)dst;
219 int tmo = net->ipv6.sysctl.icmpv6_time;
220 struct inet_peer *peer;
221
222 /* Give more bandwidth to wider prefixes. */
223 if (rt->rt6i_dst.plen < 128)
224 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
225
226 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1);
227 res = inet_peer_xrlim_allow(peer, tmo);
228 if (peer)
229 inet_putpeer(peer);
230 }
231 dst_release(dst);
232 return res;
233}
234
235/*
236 * an inline helper for the "simple" if statement below
237 * checks if parameter problem report is caused by an
238 * unrecognized IPv6 option that has the Option Type
239 * highest-order two bits set to 10
240 */
241
242static bool opt_unrec(struct sk_buff *skb, __u32 offset)
243{
244 u8 _optval, *op;
245
246 offset += skb_network_offset(skb);
247 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
248 if (!op)
249 return true;
250 return (*op & 0xC0) == 0x80;
251}
252
253void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
254 struct icmp6hdr *thdr, int len)
255{
256 struct sk_buff *skb;
257 struct icmp6hdr *icmp6h;
258
259 skb = skb_peek(&sk->sk_write_queue);
260 if (!skb)
261 return;
262
263 icmp6h = icmp6_hdr(skb);
264 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
265 icmp6h->icmp6_cksum = 0;
266
267 if (skb_queue_len(&sk->sk_write_queue) == 1) {
268 skb->csum = csum_partial(icmp6h,
269 sizeof(struct icmp6hdr), skb->csum);
270 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
271 &fl6->daddr,
272 len, fl6->flowi6_proto,
273 skb->csum);
274 } else {
275 __wsum tmp_csum = 0;
276
277 skb_queue_walk(&sk->sk_write_queue, skb) {
278 tmp_csum = csum_add(tmp_csum, skb->csum);
279 }
280
281 tmp_csum = csum_partial(icmp6h,
282 sizeof(struct icmp6hdr), tmp_csum);
283 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
284 &fl6->daddr,
285 len, fl6->flowi6_proto,
286 tmp_csum);
287 }
288 ip6_push_pending_frames(sk);
289}
290
291struct icmpv6_msg {
292 struct sk_buff *skb;
293 int offset;
294 uint8_t type;
295};
296
297static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
298{
299 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
300 struct sk_buff *org_skb = msg->skb;
301 __wsum csum = 0;
302
303 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
304 to, len, csum);
305 skb->csum = csum_block_add(skb->csum, csum, odd);
306 if (!(msg->type & ICMPV6_INFOMSG_MASK))
307 nf_ct_attach(skb, org_skb);
308 return 0;
309}
310
311#if IS_ENABLED(CONFIG_IPV6_MIP6)
312static void mip6_addr_swap(struct sk_buff *skb)
313{
314 struct ipv6hdr *iph = ipv6_hdr(skb);
315 struct inet6_skb_parm *opt = IP6CB(skb);
316 struct ipv6_destopt_hao *hao;
317 struct in6_addr tmp;
318 int off;
319
320 if (opt->dsthao) {
321 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
322 if (likely(off >= 0)) {
323 hao = (struct ipv6_destopt_hao *)
324 (skb_network_header(skb) + off);
325 tmp = iph->saddr;
326 iph->saddr = hao->addr;
327 hao->addr = tmp;
328 }
329 }
330}
331#else
332static inline void mip6_addr_swap(struct sk_buff *skb) {}
333#endif
334
335static struct dst_entry *icmpv6_route_lookup(struct net *net,
336 struct sk_buff *skb,
337 struct sock *sk,
338 struct flowi6 *fl6)
339{
340 struct dst_entry *dst, *dst2;
341 struct flowi6 fl2;
342 int err;
343
344 err = ip6_dst_lookup(net, sk, &dst, fl6);
345 if (err)
346 return ERR_PTR(err);
347
348 /*
349 * We won't send icmp if the destination is known
350 * anycast.
351 */
352 if (ipv6_anycast_destination(dst, &fl6->daddr)) {
353 net_dbg_ratelimited("icmp6_send: acast source\n");
354 dst_release(dst);
355 return ERR_PTR(-EINVAL);
356 }
357
358 /* No need to clone since we're just using its address. */
359 dst2 = dst;
360
361 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
362 if (!IS_ERR(dst)) {
363 if (dst != dst2)
364 return dst;
365 } else {
366 if (PTR_ERR(dst) == -EPERM)
367 dst = NULL;
368 else
369 return dst;
370 }
371
372 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
373 if (err)
374 goto relookup_failed;
375
376 err = ip6_dst_lookup(net, sk, &dst2, &fl2);
377 if (err)
378 goto relookup_failed;
379
380 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
381 if (!IS_ERR(dst2)) {
382 dst_release(dst);
383 dst = dst2;
384 } else {
385 err = PTR_ERR(dst2);
386 if (err == -EPERM) {
387 dst_release(dst);
388 return dst2;
389 } else
390 goto relookup_failed;
391 }
392
393relookup_failed:
394 if (dst)
395 return dst;
396 return ERR_PTR(err);
397}
398
399static int icmp6_iif(const struct sk_buff *skb)
400{
401 int iif = skb->dev->ifindex;
402
403 /* for local traffic to local address, skb dev is the loopback
404 * device. Check if there is a dst attached to the skb and if so
405 * get the real device index.
406 */
407 if (unlikely(iif == LOOPBACK_IFINDEX)) {
408 const struct rt6_info *rt6 = skb_rt6_info(skb);
409
410 if (rt6)
411 iif = rt6->rt6i_idev->dev->ifindex;
412 }
413
414 return iif;
415}
416
417/*
418 * Send an ICMP message in response to a packet in error
419 */
420static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
421 const struct in6_addr *force_saddr)
422{
423 struct net *net = dev_net(skb->dev);
424 struct inet6_dev *idev = NULL;
425 struct ipv6hdr *hdr = ipv6_hdr(skb);
426 struct sock *sk;
427 struct ipv6_pinfo *np;
428 const struct in6_addr *saddr = NULL;
429 struct dst_entry *dst;
430 struct icmp6hdr tmp_hdr;
431 struct flowi6 fl6;
432 struct icmpv6_msg msg;
433 struct sockcm_cookie sockc_unused = {0};
434 struct ipcm6_cookie ipc6;
435 int iif = 0;
436 int addr_type = 0;
437 int len;
438 u32 mark = IP6_REPLY_MARK(net, skb->mark);
439
440 if ((u8 *)hdr < skb->head ||
441 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
442 return;
443
444 /*
445 * Make sure we respect the rules
446 * i.e. RFC 1885 2.4(e)
447 * Rule (e.1) is enforced by not using icmp6_send
448 * in any code that processes icmp errors.
449 */
450 addr_type = ipv6_addr_type(&hdr->daddr);
451
452 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
453 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
454 saddr = &hdr->daddr;
455
456 /*
457 * Dest addr check
458 */
459
460 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
461 if (type != ICMPV6_PKT_TOOBIG &&
462 !(type == ICMPV6_PARAMPROB &&
463 code == ICMPV6_UNK_OPTION &&
464 (opt_unrec(skb, info))))
465 return;
466
467 saddr = NULL;
468 }
469
470 addr_type = ipv6_addr_type(&hdr->saddr);
471
472 /*
473 * Source addr check
474 */
475
476 if (__ipv6_addr_needs_scope_id(addr_type)) {
477 iif = icmp6_iif(skb);
478 } else {
479 dst = skb_dst(skb);
480 iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev);
481 }
482
483 /*
484 * Must not send error if the source does not uniquely
485 * identify a single node (RFC2463 Section 2.4).
486 * We check unspecified / multicast addresses here,
487 * and anycast addresses will be checked later.
488 */
489 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
490 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
491 &hdr->saddr, &hdr->daddr);
492 return;
493 }
494
495 /*
496 * Never answer to a ICMP packet.
497 */
498 if (is_ineligible(skb)) {
499 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
500 &hdr->saddr, &hdr->daddr);
501 return;
502 }
503
504 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */
505 local_bh_disable();
506
507 /* Check global sysctl_icmp_msgs_per_sec ratelimit */
508 if (!(skb->dev->flags&IFF_LOOPBACK) && !icmpv6_global_allow(type))
509 goto out_bh_enable;
510
511 mip6_addr_swap(skb);
512
513 memset(&fl6, 0, sizeof(fl6));
514 fl6.flowi6_proto = IPPROTO_ICMPV6;
515 fl6.daddr = hdr->saddr;
516 if (force_saddr)
517 saddr = force_saddr;
518 if (saddr)
519 fl6.saddr = *saddr;
520 fl6.flowi6_mark = mark;
521 fl6.flowi6_oif = iif;
522 fl6.fl6_icmp_type = type;
523 fl6.fl6_icmp_code = code;
524 fl6.flowi6_uid = sock_net_uid(net, NULL);
525 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
526 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
527
528 sk = icmpv6_xmit_lock(net);
529 if (!sk)
530 goto out_bh_enable;
531
532 sk->sk_mark = mark;
533 np = inet6_sk(sk);
534
535 if (!icmpv6_xrlim_allow(sk, type, &fl6))
536 goto out;
537
538 tmp_hdr.icmp6_type = type;
539 tmp_hdr.icmp6_code = code;
540 tmp_hdr.icmp6_cksum = 0;
541 tmp_hdr.icmp6_pointer = htonl(info);
542
543 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
544 fl6.flowi6_oif = np->mcast_oif;
545 else if (!fl6.flowi6_oif)
546 fl6.flowi6_oif = np->ucast_oif;
547
548 ipc6.tclass = np->tclass;
549 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
550
551 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
552 if (IS_ERR(dst))
553 goto out;
554
555 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
556 ipc6.dontfrag = np->dontfrag;
557 ipc6.opt = NULL;
558
559 msg.skb = skb;
560 msg.offset = skb_network_offset(skb);
561 msg.type = type;
562
563 len = skb->len - msg.offset;
564 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
565 if (len < 0) {
566 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
567 &hdr->saddr, &hdr->daddr);
568 goto out_dst_release;
569 }
570
571 rcu_read_lock();
572 idev = __in6_dev_get(skb->dev);
573
574 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
575 len + sizeof(struct icmp6hdr),
576 sizeof(struct icmp6hdr),
577 &ipc6, &fl6, (struct rt6_info *)dst,
578 MSG_DONTWAIT, &sockc_unused)) {
579 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
580 ip6_flush_pending_frames(sk);
581 } else {
582 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
583 len + sizeof(struct icmp6hdr));
584 }
585 rcu_read_unlock();
586out_dst_release:
587 dst_release(dst);
588out:
589 icmpv6_xmit_unlock(sk);
590out_bh_enable:
591 local_bh_enable();
592}
593
594/* Slightly more convenient version of icmp6_send.
595 */
596void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
597{
598 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL);
599 kfree_skb(skb);
600}
601
602/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
603 * if sufficient data bytes are available
604 * @nhs is the size of the tunnel header(s) :
605 * Either an IPv4 header for SIT encap
606 * an IPv4 header + GRE header for GRE encap
607 */
608int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
609 unsigned int data_len)
610{
611 struct in6_addr temp_saddr;
612 struct rt6_info *rt;
613 struct sk_buff *skb2;
614 u32 info = 0;
615
616 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
617 return 1;
618
619 /* RFC 4884 (partial) support for ICMP extensions */
620 if (data_len < 128 || (data_len & 7) || skb->len < data_len)
621 data_len = 0;
622
623 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
624
625 if (!skb2)
626 return 1;
627
628 skb_dst_drop(skb2);
629 skb_pull(skb2, nhs);
630 skb_reset_network_header(skb2);
631
632 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0,
633 skb, 0);
634
635 if (rt && rt->dst.dev)
636 skb2->dev = rt->dst.dev;
637
638 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
639
640 if (data_len) {
641 /* RFC 4884 (partial) support :
642 * insert 0 padding at the end, before the extensions
643 */
644 __skb_push(skb2, nhs);
645 skb_reset_network_header(skb2);
646 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
647 memset(skb2->data + data_len - nhs, 0, nhs);
648 /* RFC 4884 4.5 : Length is measured in 64-bit words,
649 * and stored in reserved[0]
650 */
651 info = (data_len/8) << 24;
652 }
653 if (type == ICMP_TIME_EXCEEDED)
654 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
655 info, &temp_saddr);
656 else
657 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
658 info, &temp_saddr);
659 if (rt)
660 ip6_rt_put(rt);
661
662 kfree_skb(skb2);
663
664 return 0;
665}
666EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
667
668static void icmpv6_echo_reply(struct sk_buff *skb)
669{
670 struct net *net = dev_net(skb->dev);
671 struct sock *sk;
672 struct inet6_dev *idev;
673 struct ipv6_pinfo *np;
674 const struct in6_addr *saddr = NULL;
675 struct icmp6hdr *icmph = icmp6_hdr(skb);
676 struct icmp6hdr tmp_hdr;
677 struct flowi6 fl6;
678 struct icmpv6_msg msg;
679 struct dst_entry *dst;
680 struct ipcm6_cookie ipc6;
681 u32 mark = IP6_REPLY_MARK(net, skb->mark);
682 struct sockcm_cookie sockc_unused = {0};
683
684 saddr = &ipv6_hdr(skb)->daddr;
685
686 if (!ipv6_unicast_destination(skb) &&
687 !(net->ipv6.sysctl.anycast_src_echo_reply &&
688 ipv6_anycast_destination(skb_dst(skb), saddr)))
689 saddr = NULL;
690
691 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
692 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY;
693
694 memset(&fl6, 0, sizeof(fl6));
695 fl6.flowi6_proto = IPPROTO_ICMPV6;
696 fl6.daddr = ipv6_hdr(skb)->saddr;
697 if (saddr)
698 fl6.saddr = *saddr;
699 fl6.flowi6_oif = icmp6_iif(skb);
700 fl6.fl6_icmp_type = ICMPV6_ECHO_REPLY;
701 fl6.flowi6_mark = mark;
702 fl6.flowi6_uid = sock_net_uid(net, NULL);
703 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
704
705 local_bh_disable();
706 sk = icmpv6_xmit_lock(net);
707 if (!sk)
708 goto out_bh_enable;
709 sk->sk_mark = mark;
710 np = inet6_sk(sk);
711
712 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
713 fl6.flowi6_oif = np->mcast_oif;
714 else if (!fl6.flowi6_oif)
715 fl6.flowi6_oif = np->ucast_oif;
716
717 if (ip6_dst_lookup(net, sk, &dst, &fl6))
718 goto out;
719 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
720 if (IS_ERR(dst))
721 goto out;
722
723 idev = __in6_dev_get(skb->dev);
724
725 msg.skb = skb;
726 msg.offset = 0;
727 msg.type = ICMPV6_ECHO_REPLY;
728
729 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
730 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
731 ipc6.dontfrag = np->dontfrag;
732 ipc6.opt = NULL;
733
734 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
735 skb->len + sizeof(struct icmp6hdr),
736 sizeof(struct icmp6hdr), &ipc6, &fl6,
737 (struct rt6_info *)dst, MSG_DONTWAIT,
738 &sockc_unused)) {
739 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
740 ip6_flush_pending_frames(sk);
741 } else {
742 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
743 skb->len + sizeof(struct icmp6hdr));
744 }
745 dst_release(dst);
746out:
747 icmpv6_xmit_unlock(sk);
748out_bh_enable:
749 local_bh_enable();
750}
751
752void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
753{
754 const struct inet6_protocol *ipprot;
755 int inner_offset;
756 __be16 frag_off;
757 u8 nexthdr;
758 struct net *net = dev_net(skb->dev);
759
760 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
761 goto out;
762
763 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
764 if (ipv6_ext_hdr(nexthdr)) {
765 /* now skip over extension headers */
766 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
767 &nexthdr, &frag_off);
768 if (inner_offset < 0)
769 goto out;
770 } else {
771 inner_offset = sizeof(struct ipv6hdr);
772 }
773
774 /* Checkin header including 8 bytes of inner protocol header. */
775 if (!pskb_may_pull(skb, inner_offset+8))
776 goto out;
777
778 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
779 Without this we will not able f.e. to make source routed
780 pmtu discovery.
781 Corresponding argument (opt) to notifiers is already added.
782 --ANK (980726)
783 */
784
785 ipprot = rcu_dereference(inet6_protos[nexthdr]);
786 if (ipprot && ipprot->err_handler)
787 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
788
789 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
790 return;
791
792out:
793 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
794}
795
796/*
797 * Handle icmp messages
798 */
799
800static int icmpv6_rcv(struct sk_buff *skb)
801{
802 struct net_device *dev = skb->dev;
803 struct inet6_dev *idev = __in6_dev_get(dev);
804 const struct in6_addr *saddr, *daddr;
805 struct icmp6hdr *hdr;
806 u8 type;
807 bool success = false;
808
809 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
810 struct sec_path *sp = skb_sec_path(skb);
811 int nh;
812
813 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
814 XFRM_STATE_ICMP))
815 goto drop_no_count;
816
817 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
818 goto drop_no_count;
819
820 nh = skb_network_offset(skb);
821 skb_set_network_header(skb, sizeof(*hdr));
822
823 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
824 goto drop_no_count;
825
826 skb_set_network_header(skb, nh);
827 }
828
829 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
830
831 saddr = &ipv6_hdr(skb)->saddr;
832 daddr = &ipv6_hdr(skb)->daddr;
833
834 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
835 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
836 saddr, daddr);
837 goto csum_error;
838 }
839
840 if (!pskb_pull(skb, sizeof(*hdr)))
841 goto discard_it;
842
843 hdr = icmp6_hdr(skb);
844
845 type = hdr->icmp6_type;
846
847 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
848
849 switch (type) {
850 case ICMPV6_ECHO_REQUEST:
851 icmpv6_echo_reply(skb);
852 break;
853
854 case ICMPV6_ECHO_REPLY:
855 success = ping_rcv(skb);
856 break;
857
858 case ICMPV6_PKT_TOOBIG:
859 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
860 standard destination cache. Seems, only "advanced"
861 destination cache will allow to solve this problem
862 --ANK (980726)
863 */
864 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
865 goto discard_it;
866 hdr = icmp6_hdr(skb);
867
868 /* to notify */
869 /* fall through */
870 case ICMPV6_DEST_UNREACH:
871 case ICMPV6_TIME_EXCEED:
872 case ICMPV6_PARAMPROB:
873 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
874 break;
875
876 case NDISC_ROUTER_SOLICITATION:
877 case NDISC_ROUTER_ADVERTISEMENT:
878 case NDISC_NEIGHBOUR_SOLICITATION:
879 case NDISC_NEIGHBOUR_ADVERTISEMENT:
880 case NDISC_REDIRECT:
881 ndisc_rcv(skb);
882 break;
883
884 case ICMPV6_MGM_QUERY:
885 igmp6_event_query(skb);
886 break;
887
888 case ICMPV6_MGM_REPORT:
889 igmp6_event_report(skb);
890 break;
891
892 case ICMPV6_MGM_REDUCTION:
893 case ICMPV6_NI_QUERY:
894 case ICMPV6_NI_REPLY:
895 case ICMPV6_MLD2_REPORT:
896 case ICMPV6_DHAAD_REQUEST:
897 case ICMPV6_DHAAD_REPLY:
898 case ICMPV6_MOBILE_PREFIX_SOL:
899 case ICMPV6_MOBILE_PREFIX_ADV:
900 break;
901
902 default:
903 /* informational */
904 if (type & ICMPV6_INFOMSG_MASK)
905 break;
906
907 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
908 saddr, daddr);
909
910 /*
911 * error of unknown type.
912 * must pass to upper level
913 */
914
915 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
916 }
917
918 /* until the v6 path can be better sorted assume failure and
919 * preserve the status quo behaviour for the rest of the paths to here
920 */
921 if (success)
922 consume_skb(skb);
923 else
924 kfree_skb(skb);
925
926 return 0;
927
928csum_error:
929 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
930discard_it:
931 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
932drop_no_count:
933 kfree_skb(skb);
934 return 0;
935}
936
937void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
938 u8 type,
939 const struct in6_addr *saddr,
940 const struct in6_addr *daddr,
941 int oif)
942{
943 memset(fl6, 0, sizeof(*fl6));
944 fl6->saddr = *saddr;
945 fl6->daddr = *daddr;
946 fl6->flowi6_proto = IPPROTO_ICMPV6;
947 fl6->fl6_icmp_type = type;
948 fl6->fl6_icmp_code = 0;
949 fl6->flowi6_oif = oif;
950 security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
951}
952
953static int __net_init icmpv6_sk_init(struct net *net)
954{
955 struct sock *sk;
956 int err, i, j;
957
958 net->ipv6.icmp_sk =
959 kzalloc(nr_cpu_ids * sizeof(struct sock *), GFP_KERNEL);
960 if (!net->ipv6.icmp_sk)
961 return -ENOMEM;
962
963 for_each_possible_cpu(i) {
964 err = inet_ctl_sock_create(&sk, PF_INET6,
965 SOCK_RAW, IPPROTO_ICMPV6, net);
966 if (err < 0) {
967 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
968 err);
969 goto fail;
970 }
971
972 net->ipv6.icmp_sk[i] = sk;
973
974 /* Enough space for 2 64K ICMP packets, including
975 * sk_buff struct overhead.
976 */
977 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
978 }
979 return 0;
980
981 fail:
982 for (j = 0; j < i; j++)
983 inet_ctl_sock_destroy(net->ipv6.icmp_sk[j]);
984 kfree(net->ipv6.icmp_sk);
985 return err;
986}
987
988static void __net_exit icmpv6_sk_exit(struct net *net)
989{
990 int i;
991
992 for_each_possible_cpu(i) {
993 inet_ctl_sock_destroy(net->ipv6.icmp_sk[i]);
994 }
995 kfree(net->ipv6.icmp_sk);
996}
997
998static struct pernet_operations icmpv6_sk_ops = {
999 .init = icmpv6_sk_init,
1000 .exit = icmpv6_sk_exit,
1001};
1002
1003int __init icmpv6_init(void)
1004{
1005 int err;
1006
1007 err = register_pernet_subsys(&icmpv6_sk_ops);
1008 if (err < 0)
1009 return err;
1010
1011 err = -EAGAIN;
1012 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
1013 goto fail;
1014
1015 err = inet6_register_icmp_sender(icmp6_send);
1016 if (err)
1017 goto sender_reg_err;
1018 return 0;
1019
1020sender_reg_err:
1021 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1022fail:
1023 pr_err("Failed to register ICMP6 protocol\n");
1024 unregister_pernet_subsys(&icmpv6_sk_ops);
1025 return err;
1026}
1027
1028void icmpv6_cleanup(void)
1029{
1030 inet6_unregister_icmp_sender(icmp6_send);
1031 unregister_pernet_subsys(&icmpv6_sk_ops);
1032 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1033}
1034
1035
1036static const struct icmp6_err {
1037 int err;
1038 int fatal;
1039} tab_unreach[] = {
1040 { /* NOROUTE */
1041 .err = ENETUNREACH,
1042 .fatal = 0,
1043 },
1044 { /* ADM_PROHIBITED */
1045 .err = EACCES,
1046 .fatal = 1,
1047 },
1048 { /* Was NOT_NEIGHBOUR, now reserved */
1049 .err = EHOSTUNREACH,
1050 .fatal = 0,
1051 },
1052 { /* ADDR_UNREACH */
1053 .err = EHOSTUNREACH,
1054 .fatal = 0,
1055 },
1056 { /* PORT_UNREACH */
1057 .err = ECONNREFUSED,
1058 .fatal = 1,
1059 },
1060 { /* POLICY_FAIL */
1061 .err = EACCES,
1062 .fatal = 1,
1063 },
1064 { /* REJECT_ROUTE */
1065 .err = EACCES,
1066 .fatal = 1,
1067 },
1068};
1069
1070int icmpv6_err_convert(u8 type, u8 code, int *err)
1071{
1072 int fatal = 0;
1073
1074 *err = EPROTO;
1075
1076 switch (type) {
1077 case ICMPV6_DEST_UNREACH:
1078 fatal = 1;
1079 if (code < ARRAY_SIZE(tab_unreach)) {
1080 *err = tab_unreach[code].err;
1081 fatal = tab_unreach[code].fatal;
1082 }
1083 break;
1084
1085 case ICMPV6_PKT_TOOBIG:
1086 *err = EMSGSIZE;
1087 break;
1088
1089 case ICMPV6_PARAMPROB:
1090 *err = EPROTO;
1091 fatal = 1;
1092 break;
1093
1094 case ICMPV6_TIME_EXCEED:
1095 *err = EHOSTUNREACH;
1096 break;
1097 }
1098
1099 return fatal;
1100}
1101EXPORT_SYMBOL(icmpv6_err_convert);
1102
1103#ifdef CONFIG_SYSCTL
1104static struct ctl_table ipv6_icmp_table_template[] = {
1105 {
1106 .procname = "ratelimit",
1107 .data = &init_net.ipv6.sysctl.icmpv6_time,
1108 .maxlen = sizeof(int),
1109 .mode = 0644,
1110 .proc_handler = proc_dointvec_ms_jiffies,
1111 },
1112 { },
1113};
1114
1115struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1116{
1117 struct ctl_table *table;
1118
1119 table = kmemdup(ipv6_icmp_table_template,
1120 sizeof(ipv6_icmp_table_template),
1121 GFP_KERNEL);
1122
1123 if (table)
1124 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1125
1126 return table;
1127}
1128#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Internet Control Message Protocol (ICMPv6)
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 *
9 * Based on net/ipv4/icmp.c
10 *
11 * RFC 1885
12 */
13
14/*
15 * Changes:
16 *
17 * Andi Kleen : exception handling
18 * Andi Kleen add rate limits. never reply to a icmp.
19 * add more length checks and other fixes.
20 * yoshfuji : ensure to sent parameter problem for
21 * fragments.
22 * YOSHIFUJI Hideaki @USAGI: added sysctl for icmp rate limit.
23 * Randy Dunlap and
24 * YOSHIFUJI Hideaki @USAGI: Per-interface statistics support
25 * Kazunori MIYAZAWA @USAGI: change output process to use ip6_append_data
26 */
27
28#define pr_fmt(fmt) "IPv6: " fmt
29
30#include <linux/module.h>
31#include <linux/errno.h>
32#include <linux/types.h>
33#include <linux/socket.h>
34#include <linux/in.h>
35#include <linux/kernel.h>
36#include <linux/sockios.h>
37#include <linux/net.h>
38#include <linux/skbuff.h>
39#include <linux/init.h>
40#include <linux/netfilter.h>
41#include <linux/slab.h>
42
43#ifdef CONFIG_SYSCTL
44#include <linux/sysctl.h>
45#endif
46
47#include <linux/inet.h>
48#include <linux/netdevice.h>
49#include <linux/icmpv6.h>
50
51#include <net/ip.h>
52#include <net/sock.h>
53
54#include <net/ipv6.h>
55#include <net/ip6_checksum.h>
56#include <net/ping.h>
57#include <net/protocol.h>
58#include <net/raw.h>
59#include <net/rawv6.h>
60#include <net/seg6.h>
61#include <net/transp_v6.h>
62#include <net/ip6_route.h>
63#include <net/addrconf.h>
64#include <net/icmp.h>
65#include <net/xfrm.h>
66#include <net/inet_common.h>
67#include <net/dsfield.h>
68#include <net/l3mdev.h>
69
70#include <linux/uaccess.h>
71
72static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk);
73
74static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
75 u8 type, u8 code, int offset, __be32 info)
76{
77 /* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
78 struct icmp6hdr *icmp6 = (struct icmp6hdr *) (skb->data + offset);
79 struct net *net = dev_net_rcu(skb->dev);
80
81 if (type == ICMPV6_PKT_TOOBIG)
82 ip6_update_pmtu(skb, net, info, skb->dev->ifindex, 0, sock_net_uid(net, NULL));
83 else if (type == NDISC_REDIRECT)
84 ip6_redirect(skb, net, skb->dev->ifindex, 0,
85 sock_net_uid(net, NULL));
86
87 if (!(type & ICMPV6_INFOMSG_MASK))
88 if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
89 ping_err(skb, offset, ntohl(info));
90
91 return 0;
92}
93
94static int icmpv6_rcv(struct sk_buff *skb);
95
96static const struct inet6_protocol icmpv6_protocol = {
97 .handler = icmpv6_rcv,
98 .err_handler = icmpv6_err,
99 .flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
100};
101
102/* Called with BH disabled */
103static struct sock *icmpv6_xmit_lock(struct net *net)
104{
105 struct sock *sk;
106
107 sk = this_cpu_read(ipv6_icmp_sk);
108 if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
109 /* This can happen if the output path (f.e. SIT or
110 * ip6ip6 tunnel) signals dst_link_failure() for an
111 * outgoing ICMP6 packet.
112 */
113 return NULL;
114 }
115 sock_net_set(sk, net);
116 return sk;
117}
118
119static void icmpv6_xmit_unlock(struct sock *sk)
120{
121 sock_net_set(sk, &init_net);
122 spin_unlock(&sk->sk_lock.slock);
123}
124
125/*
126 * Figure out, may we reply to this packet with icmp error.
127 *
128 * We do not reply, if:
129 * - it was icmp error message.
130 * - it is truncated, so that it is known, that protocol is ICMPV6
131 * (i.e. in the middle of some exthdr)
132 *
133 * --ANK (980726)
134 */
135
136static bool is_ineligible(const struct sk_buff *skb)
137{
138 int ptr = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
139 int len = skb->len - ptr;
140 __u8 nexthdr = ipv6_hdr(skb)->nexthdr;
141 __be16 frag_off;
142
143 if (len < 0)
144 return true;
145
146 ptr = ipv6_skip_exthdr(skb, ptr, &nexthdr, &frag_off);
147 if (ptr < 0)
148 return false;
149 if (nexthdr == IPPROTO_ICMPV6) {
150 u8 _type, *tp;
151 tp = skb_header_pointer(skb,
152 ptr+offsetof(struct icmp6hdr, icmp6_type),
153 sizeof(_type), &_type);
154
155 /* Based on RFC 8200, Section 4.5 Fragment Header, return
156 * false if this is a fragment packet with no icmp header info.
157 */
158 if (!tp && frag_off != 0)
159 return false;
160 else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
161 return true;
162 }
163 return false;
164}
165
166static bool icmpv6_mask_allow(struct net *net, int type)
167{
168 if (type > ICMPV6_MSG_MAX)
169 return true;
170
171 /* Limit if icmp type is set in ratemask. */
172 if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask))
173 return true;
174
175 return false;
176}
177
178static bool icmpv6_global_allow(struct net *net, int type,
179 bool *apply_ratelimit)
180{
181 if (icmpv6_mask_allow(net, type))
182 return true;
183
184 if (icmp_global_allow(net)) {
185 *apply_ratelimit = true;
186 return true;
187 }
188 __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL);
189 return false;
190}
191
192/*
193 * Check the ICMP output rate limit
194 */
195static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
196 struct flowi6 *fl6, bool apply_ratelimit)
197{
198 struct net *net = sock_net(sk);
199 struct dst_entry *dst;
200 bool res = false;
201
202 if (!apply_ratelimit)
203 return true;
204
205 /*
206 * Look up the output route.
207 * XXX: perhaps the expire for routing entries cloned by
208 * this lookup should be more aggressive (not longer than timeout).
209 */
210 dst = ip6_route_output(net, sk, fl6);
211 if (dst->error) {
212 IP6_INC_STATS(net, ip6_dst_idev(dst),
213 IPSTATS_MIB_OUTNOROUTES);
214 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
215 res = true;
216 } else {
217 struct rt6_info *rt = dst_rt6_info(dst);
218 int tmo = net->ipv6.sysctl.icmpv6_time;
219 struct inet_peer *peer;
220
221 /* Give more bandwidth to wider prefixes. */
222 if (rt->rt6i_dst.plen < 128)
223 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
224
225 rcu_read_lock();
226 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr);
227 res = inet_peer_xrlim_allow(peer, tmo);
228 rcu_read_unlock();
229 }
230 if (!res)
231 __ICMP6_INC_STATS(net, ip6_dst_idev(dst),
232 ICMP6_MIB_RATELIMITHOST);
233 else
234 icmp_global_consume(net);
235 dst_release(dst);
236 return res;
237}
238
239static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type,
240 struct flowi6 *fl6)
241{
242 struct net *net = sock_net(sk);
243 struct dst_entry *dst;
244 bool res = false;
245
246 dst = ip6_route_output(net, sk, fl6);
247 if (!dst->error) {
248 struct rt6_info *rt = dst_rt6_info(dst);
249 struct in6_addr prefsrc;
250
251 rt6_get_prefsrc(rt, &prefsrc);
252 res = !ipv6_addr_any(&prefsrc);
253 }
254 dst_release(dst);
255 return res;
256}
257
258/*
259 * an inline helper for the "simple" if statement below
260 * checks if parameter problem report is caused by an
261 * unrecognized IPv6 option that has the Option Type
262 * highest-order two bits set to 10
263 */
264
265static bool opt_unrec(struct sk_buff *skb, __u32 offset)
266{
267 u8 _optval, *op;
268
269 offset += skb_network_offset(skb);
270 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
271 if (!op)
272 return true;
273 return (*op & 0xC0) == 0x80;
274}
275
276void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
277 struct icmp6hdr *thdr, int len)
278{
279 struct sk_buff *skb;
280 struct icmp6hdr *icmp6h;
281
282 skb = skb_peek(&sk->sk_write_queue);
283 if (!skb)
284 return;
285
286 icmp6h = icmp6_hdr(skb);
287 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
288 icmp6h->icmp6_cksum = 0;
289
290 if (skb_queue_len(&sk->sk_write_queue) == 1) {
291 skb->csum = csum_partial(icmp6h,
292 sizeof(struct icmp6hdr), skb->csum);
293 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
294 &fl6->daddr,
295 len, fl6->flowi6_proto,
296 skb->csum);
297 } else {
298 __wsum tmp_csum = 0;
299
300 skb_queue_walk(&sk->sk_write_queue, skb) {
301 tmp_csum = csum_add(tmp_csum, skb->csum);
302 }
303
304 tmp_csum = csum_partial(icmp6h,
305 sizeof(struct icmp6hdr), tmp_csum);
306 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
307 &fl6->daddr,
308 len, fl6->flowi6_proto,
309 tmp_csum);
310 }
311 ip6_push_pending_frames(sk);
312}
313
314struct icmpv6_msg {
315 struct sk_buff *skb;
316 int offset;
317 uint8_t type;
318};
319
320static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
321{
322 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
323 struct sk_buff *org_skb = msg->skb;
324 __wsum csum;
325
326 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
327 to, len);
328 skb->csum = csum_block_add(skb->csum, csum, odd);
329 if (!(msg->type & ICMPV6_INFOMSG_MASK))
330 nf_ct_attach(skb, org_skb);
331 return 0;
332}
333
334#if IS_ENABLED(CONFIG_IPV6_MIP6)
335static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt)
336{
337 struct ipv6hdr *iph = ipv6_hdr(skb);
338 struct ipv6_destopt_hao *hao;
339 int off;
340
341 if (opt->dsthao) {
342 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
343 if (likely(off >= 0)) {
344 hao = (struct ipv6_destopt_hao *)
345 (skb_network_header(skb) + off);
346 swap(iph->saddr, hao->addr);
347 }
348 }
349}
350#else
351static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {}
352#endif
353
354static struct dst_entry *icmpv6_route_lookup(struct net *net,
355 struct sk_buff *skb,
356 struct sock *sk,
357 struct flowi6 *fl6)
358{
359 struct dst_entry *dst, *dst2;
360 struct flowi6 fl2;
361 int err;
362
363 err = ip6_dst_lookup(net, sk, &dst, fl6);
364 if (err)
365 return ERR_PTR(err);
366
367 /*
368 * We won't send icmp if the destination is known
369 * anycast unless we need to treat anycast as unicast.
370 */
371 if (!READ_ONCE(net->ipv6.sysctl.icmpv6_error_anycast_as_unicast) &&
372 ipv6_anycast_destination(dst, &fl6->daddr)) {
373 net_dbg_ratelimited("icmp6_send: acast source\n");
374 dst_release(dst);
375 return ERR_PTR(-EINVAL);
376 }
377
378 /* No need to clone since we're just using its address. */
379 dst2 = dst;
380
381 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
382 if (!IS_ERR(dst)) {
383 if (dst != dst2)
384 return dst;
385 } else {
386 if (PTR_ERR(dst) == -EPERM)
387 dst = NULL;
388 else
389 return dst;
390 }
391
392 err = xfrm_decode_session_reverse(net, skb, flowi6_to_flowi(&fl2), AF_INET6);
393 if (err)
394 goto relookup_failed;
395
396 err = ip6_dst_lookup(net, sk, &dst2, &fl2);
397 if (err)
398 goto relookup_failed;
399
400 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
401 if (!IS_ERR(dst2)) {
402 dst_release(dst);
403 dst = dst2;
404 } else {
405 err = PTR_ERR(dst2);
406 if (err == -EPERM) {
407 dst_release(dst);
408 return dst2;
409 } else
410 goto relookup_failed;
411 }
412
413relookup_failed:
414 if (dst)
415 return dst;
416 return ERR_PTR(err);
417}
418
419static struct net_device *icmp6_dev(const struct sk_buff *skb)
420{
421 struct net_device *dev = skb->dev;
422
423 /* for local traffic to local address, skb dev is the loopback
424 * device. Check if there is a dst attached to the skb and if so
425 * get the real device index. Same is needed for replies to a link
426 * local address on a device enslaved to an L3 master device
427 */
428 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
429 const struct rt6_info *rt6 = skb_rt6_info(skb);
430
431 /* The destination could be an external IP in Ext Hdr (SRv6, RPL, etc.),
432 * and ip6_null_entry could be set to skb if no route is found.
433 */
434 if (rt6 && rt6->rt6i_idev)
435 dev = rt6->rt6i_idev->dev;
436 }
437
438 return dev;
439}
440
441static int icmp6_iif(const struct sk_buff *skb)
442{
443 return icmp6_dev(skb)->ifindex;
444}
445
446/*
447 * Send an ICMP message in response to a packet in error
448 */
449void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
450 const struct in6_addr *force_saddr,
451 const struct inet6_skb_parm *parm)
452{
453 struct inet6_dev *idev = NULL;
454 struct ipv6hdr *hdr = ipv6_hdr(skb);
455 struct sock *sk;
456 struct net *net;
457 struct ipv6_pinfo *np;
458 const struct in6_addr *saddr = NULL;
459 bool apply_ratelimit = false;
460 struct dst_entry *dst;
461 struct icmp6hdr tmp_hdr;
462 struct flowi6 fl6;
463 struct icmpv6_msg msg;
464 struct ipcm6_cookie ipc6;
465 int iif = 0;
466 int addr_type = 0;
467 int len;
468 u32 mark;
469
470 if ((u8 *)hdr < skb->head ||
471 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
472 return;
473
474 if (!skb->dev)
475 return;
476
477 rcu_read_lock();
478
479 net = dev_net_rcu(skb->dev);
480 mark = IP6_REPLY_MARK(net, skb->mark);
481 /*
482 * Make sure we respect the rules
483 * i.e. RFC 1885 2.4(e)
484 * Rule (e.1) is enforced by not using icmp6_send
485 * in any code that processes icmp errors.
486 */
487 addr_type = ipv6_addr_type(&hdr->daddr);
488
489 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
490 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
491 saddr = &hdr->daddr;
492
493 /*
494 * Dest addr check
495 */
496
497 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
498 if (type != ICMPV6_PKT_TOOBIG &&
499 !(type == ICMPV6_PARAMPROB &&
500 code == ICMPV6_UNK_OPTION &&
501 (opt_unrec(skb, info))))
502 goto out;
503
504 saddr = NULL;
505 }
506
507 addr_type = ipv6_addr_type(&hdr->saddr);
508
509 /*
510 * Source addr check
511 */
512
513 if (__ipv6_addr_needs_scope_id(addr_type)) {
514 iif = icmp6_iif(skb);
515 } else {
516 /*
517 * The source device is used for looking up which routing table
518 * to use for sending an ICMP error.
519 */
520 iif = l3mdev_master_ifindex(skb->dev);
521 }
522
523 /*
524 * Must not send error if the source does not uniquely
525 * identify a single node (RFC2463 Section 2.4).
526 * We check unspecified / multicast addresses here,
527 * and anycast addresses will be checked later.
528 */
529 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
530 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
531 &hdr->saddr, &hdr->daddr);
532 goto out;
533 }
534
535 /*
536 * Never answer to a ICMP packet.
537 */
538 if (is_ineligible(skb)) {
539 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
540 &hdr->saddr, &hdr->daddr);
541 goto out;
542 }
543
544 /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */
545 local_bh_disable();
546
547 /* Check global sysctl_icmp_msgs_per_sec ratelimit */
548 if (!(skb->dev->flags & IFF_LOOPBACK) &&
549 !icmpv6_global_allow(net, type, &apply_ratelimit))
550 goto out_bh_enable;
551
552 mip6_addr_swap(skb, parm);
553
554 sk = icmpv6_xmit_lock(net);
555 if (!sk)
556 goto out_bh_enable;
557
558 memset(&fl6, 0, sizeof(fl6));
559 fl6.flowi6_proto = IPPROTO_ICMPV6;
560 fl6.daddr = hdr->saddr;
561 if (force_saddr)
562 saddr = force_saddr;
563 if (saddr) {
564 fl6.saddr = *saddr;
565 } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) {
566 /* select a more meaningful saddr from input if */
567 struct net_device *in_netdev;
568
569 in_netdev = dev_get_by_index(net, parm->iif);
570 if (in_netdev) {
571 ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr,
572 inet6_sk(sk)->srcprefs,
573 &fl6.saddr);
574 dev_put(in_netdev);
575 }
576 }
577 fl6.flowi6_mark = mark;
578 fl6.flowi6_oif = iif;
579 fl6.fl6_icmp_type = type;
580 fl6.fl6_icmp_code = code;
581 fl6.flowi6_uid = sock_net_uid(net, NULL);
582 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
583 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
584
585 np = inet6_sk(sk);
586
587 if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit))
588 goto out_unlock;
589
590 tmp_hdr.icmp6_type = type;
591 tmp_hdr.icmp6_code = code;
592 tmp_hdr.icmp6_cksum = 0;
593 tmp_hdr.icmp6_pointer = htonl(info);
594
595 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
596 fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
597 else if (!fl6.flowi6_oif)
598 fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
599
600 ipcm6_init_sk(&ipc6, sk);
601 ipc6.sockc.mark = mark;
602 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
603
604 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
605 if (IS_ERR(dst))
606 goto out_unlock;
607
608 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
609
610 msg.skb = skb;
611 msg.offset = skb_network_offset(skb);
612 msg.type = type;
613
614 len = skb->len - msg.offset;
615 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
616 if (len < 0) {
617 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
618 &hdr->saddr, &hdr->daddr);
619 goto out_dst_release;
620 }
621
622 idev = __in6_dev_get(skb->dev);
623
624 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
625 len + sizeof(struct icmp6hdr),
626 sizeof(struct icmp6hdr),
627 &ipc6, &fl6, dst_rt6_info(dst),
628 MSG_DONTWAIT)) {
629 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
630 ip6_flush_pending_frames(sk);
631 } else {
632 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
633 len + sizeof(struct icmp6hdr));
634 }
635
636out_dst_release:
637 dst_release(dst);
638out_unlock:
639 icmpv6_xmit_unlock(sk);
640out_bh_enable:
641 local_bh_enable();
642out:
643 rcu_read_unlock();
644}
645EXPORT_SYMBOL(icmp6_send);
646
647/* Slightly more convenient version of icmp6_send with drop reasons.
648 */
649void icmpv6_param_prob_reason(struct sk_buff *skb, u8 code, int pos,
650 enum skb_drop_reason reason)
651{
652 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb));
653 kfree_skb_reason(skb, reason);
654}
655
656/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
657 * if sufficient data bytes are available
658 * @nhs is the size of the tunnel header(s) :
659 * Either an IPv4 header for SIT encap
660 * an IPv4 header + GRE header for GRE encap
661 */
662int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
663 unsigned int data_len)
664{
665 struct in6_addr temp_saddr;
666 struct rt6_info *rt;
667 struct sk_buff *skb2;
668 u32 info = 0;
669
670 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
671 return 1;
672
673 /* RFC 4884 (partial) support for ICMP extensions */
674 if (data_len < 128 || (data_len & 7) || skb->len < data_len)
675 data_len = 0;
676
677 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
678
679 if (!skb2)
680 return 1;
681
682 skb_dst_drop(skb2);
683 skb_pull(skb2, nhs);
684 skb_reset_network_header(skb2);
685
686 rt = rt6_lookup(dev_net_rcu(skb->dev), &ipv6_hdr(skb2)->saddr,
687 NULL, 0, skb, 0);
688
689 if (rt && rt->dst.dev)
690 skb2->dev = rt->dst.dev;
691
692 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
693
694 if (data_len) {
695 /* RFC 4884 (partial) support :
696 * insert 0 padding at the end, before the extensions
697 */
698 __skb_push(skb2, nhs);
699 skb_reset_network_header(skb2);
700 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
701 memset(skb2->data + data_len - nhs, 0, nhs);
702 /* RFC 4884 4.5 : Length is measured in 64-bit words,
703 * and stored in reserved[0]
704 */
705 info = (data_len/8) << 24;
706 }
707 if (type == ICMP_TIME_EXCEEDED)
708 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
709 info, &temp_saddr, IP6CB(skb2));
710 else
711 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
712 info, &temp_saddr, IP6CB(skb2));
713 if (rt)
714 ip6_rt_put(rt);
715
716 kfree_skb(skb2);
717
718 return 0;
719}
720EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
721
722static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb)
723{
724 struct net *net = dev_net_rcu(skb->dev);
725 struct sock *sk;
726 struct inet6_dev *idev;
727 struct ipv6_pinfo *np;
728 const struct in6_addr *saddr = NULL;
729 struct icmp6hdr *icmph = icmp6_hdr(skb);
730 bool apply_ratelimit = false;
731 struct icmp6hdr tmp_hdr;
732 struct flowi6 fl6;
733 struct icmpv6_msg msg;
734 struct dst_entry *dst;
735 struct ipcm6_cookie ipc6;
736 u32 mark = IP6_REPLY_MARK(net, skb->mark);
737 SKB_DR(reason);
738 bool acast;
739 u8 type;
740
741 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) &&
742 net->ipv6.sysctl.icmpv6_echo_ignore_multicast)
743 return reason;
744
745 saddr = &ipv6_hdr(skb)->daddr;
746
747 acast = ipv6_anycast_destination(skb_dst(skb), saddr);
748 if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast)
749 return reason;
750
751 if (!ipv6_unicast_destination(skb) &&
752 !(net->ipv6.sysctl.anycast_src_echo_reply && acast))
753 saddr = NULL;
754
755 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)
756 type = ICMPV6_EXT_ECHO_REPLY;
757 else
758 type = ICMPV6_ECHO_REPLY;
759
760 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
761 tmp_hdr.icmp6_type = type;
762
763 memset(&fl6, 0, sizeof(fl6));
764 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES)
765 fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb));
766
767 fl6.flowi6_proto = IPPROTO_ICMPV6;
768 fl6.daddr = ipv6_hdr(skb)->saddr;
769 if (saddr)
770 fl6.saddr = *saddr;
771 fl6.flowi6_oif = icmp6_iif(skb);
772 fl6.fl6_icmp_type = type;
773 fl6.flowi6_mark = mark;
774 fl6.flowi6_uid = sock_net_uid(net, NULL);
775 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
776
777 local_bh_disable();
778 sk = icmpv6_xmit_lock(net);
779 if (!sk)
780 goto out_bh_enable;
781 np = inet6_sk(sk);
782
783 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
784 fl6.flowi6_oif = READ_ONCE(np->mcast_oif);
785 else if (!fl6.flowi6_oif)
786 fl6.flowi6_oif = READ_ONCE(np->ucast_oif);
787
788 if (ip6_dst_lookup(net, sk, &dst, &fl6))
789 goto out;
790 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
791 if (IS_ERR(dst))
792 goto out;
793
794 /* Check the ratelimit */
795 if ((!(skb->dev->flags & IFF_LOOPBACK) &&
796 !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) ||
797 !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit))
798 goto out_dst_release;
799
800 idev = __in6_dev_get(skb->dev);
801
802 msg.skb = skb;
803 msg.offset = 0;
804 msg.type = type;
805
806 ipcm6_init_sk(&ipc6, sk);
807 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
808 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb));
809 ipc6.sockc.mark = mark;
810
811 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST)
812 if (!icmp_build_probe(skb, (struct icmphdr *)&tmp_hdr))
813 goto out_dst_release;
814
815 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
816 skb->len + sizeof(struct icmp6hdr),
817 sizeof(struct icmp6hdr), &ipc6, &fl6,
818 dst_rt6_info(dst), MSG_DONTWAIT)) {
819 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
820 ip6_flush_pending_frames(sk);
821 } else {
822 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
823 skb->len + sizeof(struct icmp6hdr));
824 reason = SKB_CONSUMED;
825 }
826out_dst_release:
827 dst_release(dst);
828out:
829 icmpv6_xmit_unlock(sk);
830out_bh_enable:
831 local_bh_enable();
832 return reason;
833}
834
835enum skb_drop_reason icmpv6_notify(struct sk_buff *skb, u8 type,
836 u8 code, __be32 info)
837{
838 struct inet6_skb_parm *opt = IP6CB(skb);
839 struct net *net = dev_net_rcu(skb->dev);
840 const struct inet6_protocol *ipprot;
841 enum skb_drop_reason reason;
842 int inner_offset;
843 __be16 frag_off;
844 u8 nexthdr;
845
846 reason = pskb_may_pull_reason(skb, sizeof(struct ipv6hdr));
847 if (reason != SKB_NOT_DROPPED_YET)
848 goto out;
849
850 seg6_icmp_srh(skb, opt);
851
852 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
853 if (ipv6_ext_hdr(nexthdr)) {
854 /* now skip over extension headers */
855 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
856 &nexthdr, &frag_off);
857 if (inner_offset < 0) {
858 SKB_DR_SET(reason, IPV6_BAD_EXTHDR);
859 goto out;
860 }
861 } else {
862 inner_offset = sizeof(struct ipv6hdr);
863 }
864
865 /* Checkin header including 8 bytes of inner protocol header. */
866 reason = pskb_may_pull_reason(skb, inner_offset + 8);
867 if (reason != SKB_NOT_DROPPED_YET)
868 goto out;
869
870 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
871 Without this we will not able f.e. to make source routed
872 pmtu discovery.
873 Corresponding argument (opt) to notifiers is already added.
874 --ANK (980726)
875 */
876
877 ipprot = rcu_dereference(inet6_protos[nexthdr]);
878 if (ipprot && ipprot->err_handler)
879 ipprot->err_handler(skb, opt, type, code, inner_offset, info);
880
881 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
882 return SKB_CONSUMED;
883
884out:
885 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
886 return reason;
887}
888
889/*
890 * Handle icmp messages
891 */
892
893static int icmpv6_rcv(struct sk_buff *skb)
894{
895 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
896 struct net *net = dev_net_rcu(skb->dev);
897 struct net_device *dev = icmp6_dev(skb);
898 struct inet6_dev *idev = __in6_dev_get(dev);
899 const struct in6_addr *saddr, *daddr;
900 struct icmp6hdr *hdr;
901 u8 type;
902
903 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
904 struct sec_path *sp = skb_sec_path(skb);
905 int nh;
906
907 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
908 XFRM_STATE_ICMP)) {
909 reason = SKB_DROP_REASON_XFRM_POLICY;
910 goto drop_no_count;
911 }
912
913 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
914 goto drop_no_count;
915
916 nh = skb_network_offset(skb);
917 skb_set_network_header(skb, sizeof(*hdr));
918
919 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN,
920 skb)) {
921 reason = SKB_DROP_REASON_XFRM_POLICY;
922 goto drop_no_count;
923 }
924
925 skb_set_network_header(skb, nh);
926 }
927
928 __ICMP6_INC_STATS(dev_net_rcu(dev), idev, ICMP6_MIB_INMSGS);
929
930 saddr = &ipv6_hdr(skb)->saddr;
931 daddr = &ipv6_hdr(skb)->daddr;
932
933 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
934 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
935 saddr, daddr);
936 goto csum_error;
937 }
938
939 if (!pskb_pull(skb, sizeof(*hdr)))
940 goto discard_it;
941
942 hdr = icmp6_hdr(skb);
943
944 type = hdr->icmp6_type;
945
946 ICMP6MSGIN_INC_STATS(dev_net_rcu(dev), idev, type);
947
948 switch (type) {
949 case ICMPV6_ECHO_REQUEST:
950 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)
951 reason = icmpv6_echo_reply(skb);
952 break;
953 case ICMPV6_EXT_ECHO_REQUEST:
954 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&
955 READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe))
956 reason = icmpv6_echo_reply(skb);
957 break;
958
959 case ICMPV6_ECHO_REPLY:
960 reason = ping_rcv(skb);
961 break;
962
963 case ICMPV6_EXT_ECHO_REPLY:
964 reason = ping_rcv(skb);
965 break;
966
967 case ICMPV6_PKT_TOOBIG:
968 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
969 standard destination cache. Seems, only "advanced"
970 destination cache will allow to solve this problem
971 --ANK (980726)
972 */
973 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
974 goto discard_it;
975 hdr = icmp6_hdr(skb);
976
977 /* to notify */
978 fallthrough;
979 case ICMPV6_DEST_UNREACH:
980 case ICMPV6_TIME_EXCEED:
981 case ICMPV6_PARAMPROB:
982 reason = icmpv6_notify(skb, type, hdr->icmp6_code,
983 hdr->icmp6_mtu);
984 break;
985
986 case NDISC_ROUTER_SOLICITATION:
987 case NDISC_ROUTER_ADVERTISEMENT:
988 case NDISC_NEIGHBOUR_SOLICITATION:
989 case NDISC_NEIGHBOUR_ADVERTISEMENT:
990 case NDISC_REDIRECT:
991 reason = ndisc_rcv(skb);
992 break;
993
994 case ICMPV6_MGM_QUERY:
995 igmp6_event_query(skb);
996 return 0;
997
998 case ICMPV6_MGM_REPORT:
999 igmp6_event_report(skb);
1000 return 0;
1001
1002 case ICMPV6_MGM_REDUCTION:
1003 case ICMPV6_NI_QUERY:
1004 case ICMPV6_NI_REPLY:
1005 case ICMPV6_MLD2_REPORT:
1006 case ICMPV6_DHAAD_REQUEST:
1007 case ICMPV6_DHAAD_REPLY:
1008 case ICMPV6_MOBILE_PREFIX_SOL:
1009 case ICMPV6_MOBILE_PREFIX_ADV:
1010 break;
1011
1012 default:
1013 /* informational */
1014 if (type & ICMPV6_INFOMSG_MASK)
1015 break;
1016
1017 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
1018 saddr, daddr);
1019
1020 /*
1021 * error of unknown type.
1022 * must pass to upper level
1023 */
1024
1025 reason = icmpv6_notify(skb, type, hdr->icmp6_code,
1026 hdr->icmp6_mtu);
1027 }
1028
1029 /* until the v6 path can be better sorted assume failure and
1030 * preserve the status quo behaviour for the rest of the paths to here
1031 */
1032 if (reason)
1033 kfree_skb_reason(skb, reason);
1034 else
1035 consume_skb(skb);
1036
1037 return 0;
1038
1039csum_error:
1040 reason = SKB_DROP_REASON_ICMP_CSUM;
1041 __ICMP6_INC_STATS(dev_net_rcu(dev), idev, ICMP6_MIB_CSUMERRORS);
1042discard_it:
1043 __ICMP6_INC_STATS(dev_net_rcu(dev), idev, ICMP6_MIB_INERRORS);
1044drop_no_count:
1045 kfree_skb_reason(skb, reason);
1046 return 0;
1047}
1048
1049void icmpv6_flow_init(const struct sock *sk, struct flowi6 *fl6, u8 type,
1050 const struct in6_addr *saddr,
1051 const struct in6_addr *daddr, int oif)
1052{
1053 memset(fl6, 0, sizeof(*fl6));
1054 fl6->saddr = *saddr;
1055 fl6->daddr = *daddr;
1056 fl6->flowi6_proto = IPPROTO_ICMPV6;
1057 fl6->fl6_icmp_type = type;
1058 fl6->fl6_icmp_code = 0;
1059 fl6->flowi6_oif = oif;
1060 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
1061}
1062
1063int __init icmpv6_init(void)
1064{
1065 struct sock *sk;
1066 int err, i;
1067
1068 for_each_possible_cpu(i) {
1069 err = inet_ctl_sock_create(&sk, PF_INET6,
1070 SOCK_RAW, IPPROTO_ICMPV6, &init_net);
1071 if (err < 0) {
1072 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
1073 err);
1074 return err;
1075 }
1076
1077 per_cpu(ipv6_icmp_sk, i) = sk;
1078
1079 /* Enough space for 2 64K ICMP packets, including
1080 * sk_buff struct overhead.
1081 */
1082 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1083 }
1084
1085 err = -EAGAIN;
1086 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
1087 goto fail;
1088
1089 err = inet6_register_icmp_sender(icmp6_send);
1090 if (err)
1091 goto sender_reg_err;
1092 return 0;
1093
1094sender_reg_err:
1095 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1096fail:
1097 pr_err("Failed to register ICMP6 protocol\n");
1098 return err;
1099}
1100
1101void icmpv6_cleanup(void)
1102{
1103 inet6_unregister_icmp_sender(icmp6_send);
1104 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1105}
1106
1107
1108static const struct icmp6_err {
1109 int err;
1110 int fatal;
1111} tab_unreach[] = {
1112 { /* NOROUTE */
1113 .err = ENETUNREACH,
1114 .fatal = 0,
1115 },
1116 { /* ADM_PROHIBITED */
1117 .err = EACCES,
1118 .fatal = 1,
1119 },
1120 { /* Was NOT_NEIGHBOUR, now reserved */
1121 .err = EHOSTUNREACH,
1122 .fatal = 0,
1123 },
1124 { /* ADDR_UNREACH */
1125 .err = EHOSTUNREACH,
1126 .fatal = 0,
1127 },
1128 { /* PORT_UNREACH */
1129 .err = ECONNREFUSED,
1130 .fatal = 1,
1131 },
1132 { /* POLICY_FAIL */
1133 .err = EACCES,
1134 .fatal = 1,
1135 },
1136 { /* REJECT_ROUTE */
1137 .err = EACCES,
1138 .fatal = 1,
1139 },
1140};
1141
1142int icmpv6_err_convert(u8 type, u8 code, int *err)
1143{
1144 int fatal = 0;
1145
1146 *err = EPROTO;
1147
1148 switch (type) {
1149 case ICMPV6_DEST_UNREACH:
1150 fatal = 1;
1151 if (code < ARRAY_SIZE(tab_unreach)) {
1152 *err = tab_unreach[code].err;
1153 fatal = tab_unreach[code].fatal;
1154 }
1155 break;
1156
1157 case ICMPV6_PKT_TOOBIG:
1158 *err = EMSGSIZE;
1159 break;
1160
1161 case ICMPV6_PARAMPROB:
1162 *err = EPROTO;
1163 fatal = 1;
1164 break;
1165
1166 case ICMPV6_TIME_EXCEED:
1167 *err = EHOSTUNREACH;
1168 break;
1169 }
1170
1171 return fatal;
1172}
1173EXPORT_SYMBOL(icmpv6_err_convert);
1174
1175#ifdef CONFIG_SYSCTL
1176static struct ctl_table ipv6_icmp_table_template[] = {
1177 {
1178 .procname = "ratelimit",
1179 .data = &init_net.ipv6.sysctl.icmpv6_time,
1180 .maxlen = sizeof(int),
1181 .mode = 0644,
1182 .proc_handler = proc_dointvec_ms_jiffies,
1183 },
1184 {
1185 .procname = "echo_ignore_all",
1186 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all,
1187 .maxlen = sizeof(u8),
1188 .mode = 0644,
1189 .proc_handler = proc_dou8vec_minmax,
1190 },
1191 {
1192 .procname = "echo_ignore_multicast",
1193 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
1194 .maxlen = sizeof(u8),
1195 .mode = 0644,
1196 .proc_handler = proc_dou8vec_minmax,
1197 },
1198 {
1199 .procname = "echo_ignore_anycast",
1200 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
1201 .maxlen = sizeof(u8),
1202 .mode = 0644,
1203 .proc_handler = proc_dou8vec_minmax,
1204 },
1205 {
1206 .procname = "ratemask",
1207 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr,
1208 .maxlen = ICMPV6_MSG_MAX + 1,
1209 .mode = 0644,
1210 .proc_handler = proc_do_large_bitmap,
1211 },
1212 {
1213 .procname = "error_anycast_as_unicast",
1214 .data = &init_net.ipv6.sysctl.icmpv6_error_anycast_as_unicast,
1215 .maxlen = sizeof(u8),
1216 .mode = 0644,
1217 .proc_handler = proc_dou8vec_minmax,
1218 .extra1 = SYSCTL_ZERO,
1219 .extra2 = SYSCTL_ONE,
1220 },
1221};
1222
1223struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1224{
1225 struct ctl_table *table;
1226
1227 table = kmemdup(ipv6_icmp_table_template,
1228 sizeof(ipv6_icmp_table_template),
1229 GFP_KERNEL);
1230
1231 if (table) {
1232 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1233 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
1234 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
1235 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast;
1236 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr;
1237 table[5].data = &net->ipv6.sysctl.icmpv6_error_anycast_as_unicast;
1238 }
1239 return table;
1240}
1241
1242size_t ipv6_icmp_sysctl_table_size(void)
1243{
1244 return ARRAY_SIZE(ipv6_icmp_table_template);
1245}
1246#endif