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