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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
162 /* Based on RFC 8200, Section 4.5 Fragment Header, return
163 * false if this is a fragment packet with no icmp header info.
164 */
165 if (!tp && frag_off != 0)
166 return false;
167 else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK))
168 return true;
169 }
170 return false;
171}
172
173static bool icmpv6_mask_allow(struct net *net, int type)
174{
175 if (type > ICMPV6_MSG_MAX)
176 return true;
177
178 /* Limit if icmp type is set in ratemask. */
179 if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask))
180 return true;
181
182 return false;
183}
184
185static bool icmpv6_global_allow(struct net *net, int type)
186{
187 if (icmpv6_mask_allow(net, type))
188 return true;
189
190 if (icmp_global_allow())
191 return true;
192
193 return false;
194}
195
196/*
197 * Check the ICMP output rate limit
198 */
199static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
200 struct flowi6 *fl6)
201{
202 struct net *net = sock_net(sk);
203 struct dst_entry *dst;
204 bool res = false;
205
206 if (icmpv6_mask_allow(net, type))
207 return true;
208
209 /*
210 * Look up the output route.
211 * XXX: perhaps the expire for routing entries cloned by
212 * this lookup should be more aggressive (not longer than timeout).
213 */
214 dst = ip6_route_output(net, sk, fl6);
215 if (dst->error) {
216 IP6_INC_STATS(net, ip6_dst_idev(dst),
217 IPSTATS_MIB_OUTNOROUTES);
218 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
219 res = true;
220 } else {
221 struct rt6_info *rt = (struct rt6_info *)dst;
222 int tmo = net->ipv6.sysctl.icmpv6_time;
223 struct inet_peer *peer;
224
225 /* Give more bandwidth to wider prefixes. */
226 if (rt->rt6i_dst.plen < 128)
227 tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
228
229 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1);
230 res = inet_peer_xrlim_allow(peer, tmo);
231 if (peer)
232 inet_putpeer(peer);
233 }
234 dst_release(dst);
235 return res;
236}
237
238static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type,
239 struct flowi6 *fl6)
240{
241 struct net *net = sock_net(sk);
242 struct dst_entry *dst;
243 bool res = false;
244
245 dst = ip6_route_output(net, sk, fl6);
246 if (!dst->error) {
247 struct rt6_info *rt = (struct rt6_info *)dst;
248 struct in6_addr prefsrc;
249
250 rt6_get_prefsrc(rt, &prefsrc);
251 res = !ipv6_addr_any(&prefsrc);
252 }
253 dst_release(dst);
254 return res;
255}
256
257/*
258 * an inline helper for the "simple" if statement below
259 * checks if parameter problem report is caused by an
260 * unrecognized IPv6 option that has the Option Type
261 * highest-order two bits set to 10
262 */
263
264static bool opt_unrec(struct sk_buff *skb, __u32 offset)
265{
266 u8 _optval, *op;
267
268 offset += skb_network_offset(skb);
269 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval);
270 if (!op)
271 return true;
272 return (*op & 0xC0) == 0x80;
273}
274
275void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
276 struct icmp6hdr *thdr, int len)
277{
278 struct sk_buff *skb;
279 struct icmp6hdr *icmp6h;
280
281 skb = skb_peek(&sk->sk_write_queue);
282 if (!skb)
283 return;
284
285 icmp6h = icmp6_hdr(skb);
286 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr));
287 icmp6h->icmp6_cksum = 0;
288
289 if (skb_queue_len(&sk->sk_write_queue) == 1) {
290 skb->csum = csum_partial(icmp6h,
291 sizeof(struct icmp6hdr), skb->csum);
292 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
293 &fl6->daddr,
294 len, fl6->flowi6_proto,
295 skb->csum);
296 } else {
297 __wsum tmp_csum = 0;
298
299 skb_queue_walk(&sk->sk_write_queue, skb) {
300 tmp_csum = csum_add(tmp_csum, skb->csum);
301 }
302
303 tmp_csum = csum_partial(icmp6h,
304 sizeof(struct icmp6hdr), tmp_csum);
305 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr,
306 &fl6->daddr,
307 len, fl6->flowi6_proto,
308 tmp_csum);
309 }
310 ip6_push_pending_frames(sk);
311}
312
313struct icmpv6_msg {
314 struct sk_buff *skb;
315 int offset;
316 uint8_t type;
317};
318
319static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
320{
321 struct icmpv6_msg *msg = (struct icmpv6_msg *) from;
322 struct sk_buff *org_skb = msg->skb;
323 __wsum csum;
324
325 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset,
326 to, len);
327 skb->csum = csum_block_add(skb->csum, csum, odd);
328 if (!(msg->type & ICMPV6_INFOMSG_MASK))
329 nf_ct_attach(skb, org_skb);
330 return 0;
331}
332
333#if IS_ENABLED(CONFIG_IPV6_MIP6)
334static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt)
335{
336 struct ipv6hdr *iph = ipv6_hdr(skb);
337 struct ipv6_destopt_hao *hao;
338 struct in6_addr tmp;
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 tmp = iph->saddr;
347 iph->saddr = hao->addr;
348 hao->addr = tmp;
349 }
350 }
351}
352#else
353static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {}
354#endif
355
356static struct dst_entry *icmpv6_route_lookup(struct net *net,
357 struct sk_buff *skb,
358 struct sock *sk,
359 struct flowi6 *fl6)
360{
361 struct dst_entry *dst, *dst2;
362 struct flowi6 fl2;
363 int err;
364
365 err = ip6_dst_lookup(net, sk, &dst, fl6);
366 if (err)
367 return ERR_PTR(err);
368
369 /*
370 * We won't send icmp if the destination is known
371 * anycast.
372 */
373 if (ipv6_anycast_destination(dst, &fl6->daddr)) {
374 net_dbg_ratelimited("icmp6_send: acast source\n");
375 dst_release(dst);
376 return ERR_PTR(-EINVAL);
377 }
378
379 /* No need to clone since we're just using its address. */
380 dst2 = dst;
381
382 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0);
383 if (!IS_ERR(dst)) {
384 if (dst != dst2)
385 return dst;
386 } else {
387 if (PTR_ERR(dst) == -EPERM)
388 dst = NULL;
389 else
390 return dst;
391 }
392
393 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6);
394 if (err)
395 goto relookup_failed;
396
397 err = ip6_dst_lookup(net, sk, &dst2, &fl2);
398 if (err)
399 goto relookup_failed;
400
401 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP);
402 if (!IS_ERR(dst2)) {
403 dst_release(dst);
404 dst = dst2;
405 } else {
406 err = PTR_ERR(dst2);
407 if (err == -EPERM) {
408 dst_release(dst);
409 return dst2;
410 } else
411 goto relookup_failed;
412 }
413
414relookup_failed:
415 if (dst)
416 return dst;
417 return ERR_PTR(err);
418}
419
420static struct net_device *icmp6_dev(const struct sk_buff *skb)
421{
422 struct net_device *dev = skb->dev;
423
424 /* for local traffic to local address, skb dev is the loopback
425 * device. Check if there is a dst attached to the skb and if so
426 * get the real device index. Same is needed for replies to a link
427 * local address on a device enslaved to an L3 master device
428 */
429 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) {
430 const struct rt6_info *rt6 = skb_rt6_info(skb);
431
432 if (rt6)
433 dev = rt6->rt6i_idev->dev;
434 }
435
436 return dev;
437}
438
439static int icmp6_iif(const struct sk_buff *skb)
440{
441 return icmp6_dev(skb)->ifindex;
442}
443
444/*
445 * Send an ICMP message in response to a packet in error
446 */
447void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
448 const struct in6_addr *force_saddr,
449 const struct inet6_skb_parm *parm)
450{
451 struct inet6_dev *idev = NULL;
452 struct ipv6hdr *hdr = ipv6_hdr(skb);
453 struct sock *sk;
454 struct net *net;
455 struct ipv6_pinfo *np;
456 const struct in6_addr *saddr = NULL;
457 struct dst_entry *dst;
458 struct icmp6hdr tmp_hdr;
459 struct flowi6 fl6;
460 struct icmpv6_msg msg;
461 struct ipcm6_cookie ipc6;
462 int iif = 0;
463 int addr_type = 0;
464 int len;
465 u32 mark;
466
467 if ((u8 *)hdr < skb->head ||
468 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb))
469 return;
470
471 if (!skb->dev)
472 return;
473 net = dev_net(skb->dev);
474 mark = IP6_REPLY_MARK(net, skb->mark);
475 /*
476 * Make sure we respect the rules
477 * i.e. RFC 1885 2.4(e)
478 * Rule (e.1) is enforced by not using icmp6_send
479 * in any code that processes icmp errors.
480 */
481 addr_type = ipv6_addr_type(&hdr->daddr);
482
483 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) ||
484 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr))
485 saddr = &hdr->daddr;
486
487 /*
488 * Dest addr check
489 */
490
491 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) {
492 if (type != ICMPV6_PKT_TOOBIG &&
493 !(type == ICMPV6_PARAMPROB &&
494 code == ICMPV6_UNK_OPTION &&
495 (opt_unrec(skb, info))))
496 return;
497
498 saddr = NULL;
499 }
500
501 addr_type = ipv6_addr_type(&hdr->saddr);
502
503 /*
504 * Source addr check
505 */
506
507 if (__ipv6_addr_needs_scope_id(addr_type)) {
508 iif = icmp6_iif(skb);
509 } else {
510 /*
511 * The source device is used for looking up which routing table
512 * to use for sending an ICMP error.
513 */
514 iif = l3mdev_master_ifindex(skb->dev);
515 }
516
517 /*
518 * Must not send error if the source does not uniquely
519 * identify a single node (RFC2463 Section 2.4).
520 * We check unspecified / multicast addresses here,
521 * and anycast addresses will be checked later.
522 */
523 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
524 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n",
525 &hdr->saddr, &hdr->daddr);
526 return;
527 }
528
529 /*
530 * Never answer to a ICMP packet.
531 */
532 if (is_ineligible(skb)) {
533 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n",
534 &hdr->saddr, &hdr->daddr);
535 return;
536 }
537
538 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */
539 local_bh_disable();
540
541 /* Check global sysctl_icmp_msgs_per_sec ratelimit */
542 if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type))
543 goto out_bh_enable;
544
545 mip6_addr_swap(skb, parm);
546
547 sk = icmpv6_xmit_lock(net);
548 if (!sk)
549 goto out_bh_enable;
550
551 memset(&fl6, 0, sizeof(fl6));
552 fl6.flowi6_proto = IPPROTO_ICMPV6;
553 fl6.daddr = hdr->saddr;
554 if (force_saddr)
555 saddr = force_saddr;
556 if (saddr) {
557 fl6.saddr = *saddr;
558 } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) {
559 /* select a more meaningful saddr from input if */
560 struct net_device *in_netdev;
561
562 in_netdev = dev_get_by_index(net, parm->iif);
563 if (in_netdev) {
564 ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr,
565 inet6_sk(sk)->srcprefs,
566 &fl6.saddr);
567 dev_put(in_netdev);
568 }
569 }
570 fl6.flowi6_mark = mark;
571 fl6.flowi6_oif = iif;
572 fl6.fl6_icmp_type = type;
573 fl6.fl6_icmp_code = code;
574 fl6.flowi6_uid = sock_net_uid(net, NULL);
575 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
576 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6));
577
578 np = inet6_sk(sk);
579
580 if (!icmpv6_xrlim_allow(sk, type, &fl6))
581 goto out;
582
583 tmp_hdr.icmp6_type = type;
584 tmp_hdr.icmp6_code = code;
585 tmp_hdr.icmp6_cksum = 0;
586 tmp_hdr.icmp6_pointer = htonl(info);
587
588 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
589 fl6.flowi6_oif = np->mcast_oif;
590 else if (!fl6.flowi6_oif)
591 fl6.flowi6_oif = np->ucast_oif;
592
593 ipcm6_init_sk(&ipc6, np);
594 ipc6.sockc.mark = mark;
595 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);
596
597 dst = icmpv6_route_lookup(net, skb, sk, &fl6);
598 if (IS_ERR(dst))
599 goto out;
600
601 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);
602
603 msg.skb = skb;
604 msg.offset = skb_network_offset(skb);
605 msg.type = type;
606
607 len = skb->len - msg.offset;
608 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr));
609 if (len < 0) {
610 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n",
611 &hdr->saddr, &hdr->daddr);
612 goto out_dst_release;
613 }
614
615 rcu_read_lock();
616 idev = __in6_dev_get(skb->dev);
617
618 if (ip6_append_data(sk, icmpv6_getfrag, &msg,
619 len + sizeof(struct icmp6hdr),
620 sizeof(struct icmp6hdr),
621 &ipc6, &fl6, (struct rt6_info *)dst,
622 MSG_DONTWAIT)) {
623 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS);
624 ip6_flush_pending_frames(sk);
625 } else {
626 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr,
627 len + sizeof(struct icmp6hdr));
628 }
629 rcu_read_unlock();
630out_dst_release:
631 dst_release(dst);
632out:
633 icmpv6_xmit_unlock(sk);
634out_bh_enable:
635 local_bh_enable();
636}
637EXPORT_SYMBOL(icmp6_send);
638
639/* Slightly more convenient version of icmp6_send.
640 */
641void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
642{
643 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb));
644 kfree_skb(skb);
645}
646
647/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
648 * if sufficient data bytes are available
649 * @nhs is the size of the tunnel header(s) :
650 * Either an IPv4 header for SIT encap
651 * an IPv4 header + GRE header for GRE encap
652 */
653int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
654 unsigned int data_len)
655{
656 struct in6_addr temp_saddr;
657 struct rt6_info *rt;
658 struct sk_buff *skb2;
659 u32 info = 0;
660
661 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8))
662 return 1;
663
664 /* RFC 4884 (partial) support for ICMP extensions */
665 if (data_len < 128 || (data_len & 7) || skb->len < data_len)
666 data_len = 0;
667
668 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC);
669
670 if (!skb2)
671 return 1;
672
673 skb_dst_drop(skb2);
674 skb_pull(skb2, nhs);
675 skb_reset_network_header(skb2);
676
677 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0,
678 skb, 0);
679
680 if (rt && rt->dst.dev)
681 skb2->dev = rt->dst.dev;
682
683 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr);
684
685 if (data_len) {
686 /* RFC 4884 (partial) support :
687 * insert 0 padding at the end, before the extensions
688 */
689 __skb_push(skb2, nhs);
690 skb_reset_network_header(skb2);
691 memmove(skb2->data, skb2->data + nhs, data_len - nhs);
692 memset(skb2->data + data_len - nhs, 0, nhs);
693 /* RFC 4884 4.5 : Length is measured in 64-bit words,
694 * and stored in reserved[0]
695 */
696 info = (data_len/8) << 24;
697 }
698 if (type == ICMP_TIME_EXCEEDED)
699 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
700 info, &temp_saddr, IP6CB(skb2));
701 else
702 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH,
703 info, &temp_saddr, IP6CB(skb2));
704 if (rt)
705 ip6_rt_put(rt);
706
707 kfree_skb(skb2);
708
709 return 0;
710}
711EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach);
712
713static void icmpv6_echo_reply(struct sk_buff *skb)
714{
715 struct net *net = dev_net(skb->dev);
716 struct sock *sk;
717 struct inet6_dev *idev;
718 struct ipv6_pinfo *np;
719 const struct in6_addr *saddr = NULL;
720 struct icmp6hdr *icmph = icmp6_hdr(skb);
721 struct icmp6hdr tmp_hdr;
722 struct flowi6 fl6;
723 struct icmpv6_msg msg;
724 struct dst_entry *dst;
725 struct ipcm6_cookie ipc6;
726 u32 mark = IP6_REPLY_MARK(net, skb->mark);
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;
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;
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 = np->mcast_oif;
774 else if (!fl6.flowi6_oif)
775 fl6.flowi6_oif = 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, np);
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 }
813out_dst_release:
814 dst_release(dst);
815out:
816 icmpv6_xmit_unlock(sk);
817out_bh_enable:
818 local_bh_enable();
819}
820
821void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
822{
823 const struct inet6_protocol *ipprot;
824 int inner_offset;
825 __be16 frag_off;
826 u8 nexthdr;
827 struct net *net = dev_net(skb->dev);
828
829 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
830 goto out;
831
832 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr;
833 if (ipv6_ext_hdr(nexthdr)) {
834 /* now skip over extension headers */
835 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
836 &nexthdr, &frag_off);
837 if (inner_offset < 0)
838 goto out;
839 } else {
840 inner_offset = sizeof(struct ipv6hdr);
841 }
842
843 /* Checkin header including 8 bytes of inner protocol header. */
844 if (!pskb_may_pull(skb, inner_offset+8))
845 goto out;
846
847 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet.
848 Without this we will not able f.e. to make source routed
849 pmtu discovery.
850 Corresponding argument (opt) to notifiers is already added.
851 --ANK (980726)
852 */
853
854 ipprot = rcu_dereference(inet6_protos[nexthdr]);
855 if (ipprot && ipprot->err_handler)
856 ipprot->err_handler(skb, NULL, type, code, inner_offset, info);
857
858 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info);
859 return;
860
861out:
862 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
863}
864
865/*
866 * Handle icmp messages
867 */
868
869static int icmpv6_rcv(struct sk_buff *skb)
870{
871 struct net *net = dev_net(skb->dev);
872 struct net_device *dev = icmp6_dev(skb);
873 struct inet6_dev *idev = __in6_dev_get(dev);
874 const struct in6_addr *saddr, *daddr;
875 struct icmp6hdr *hdr;
876 u8 type;
877 bool success = false;
878
879 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
880 struct sec_path *sp = skb_sec_path(skb);
881 int nh;
882
883 if (!(sp && sp->xvec[sp->len - 1]->props.flags &
884 XFRM_STATE_ICMP))
885 goto drop_no_count;
886
887 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
888 goto drop_no_count;
889
890 nh = skb_network_offset(skb);
891 skb_set_network_header(skb, sizeof(*hdr));
892
893 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
894 goto drop_no_count;
895
896 skb_set_network_header(skb, nh);
897 }
898
899 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS);
900
901 saddr = &ipv6_hdr(skb)->saddr;
902 daddr = &ipv6_hdr(skb)->daddr;
903
904 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) {
905 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n",
906 saddr, daddr);
907 goto csum_error;
908 }
909
910 if (!pskb_pull(skb, sizeof(*hdr)))
911 goto discard_it;
912
913 hdr = icmp6_hdr(skb);
914
915 type = hdr->icmp6_type;
916
917 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type);
918
919 switch (type) {
920 case ICMPV6_ECHO_REQUEST:
921 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all)
922 icmpv6_echo_reply(skb);
923 break;
924 case ICMPV6_EXT_ECHO_REQUEST:
925 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all &&
926 net->ipv4.sysctl_icmp_echo_enable_probe)
927 icmpv6_echo_reply(skb);
928 break;
929
930 case ICMPV6_ECHO_REPLY:
931 success = ping_rcv(skb);
932 break;
933
934 case ICMPV6_EXT_ECHO_REPLY:
935 success = ping_rcv(skb);
936 break;
937
938 case ICMPV6_PKT_TOOBIG:
939 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update
940 standard destination cache. Seems, only "advanced"
941 destination cache will allow to solve this problem
942 --ANK (980726)
943 */
944 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
945 goto discard_it;
946 hdr = icmp6_hdr(skb);
947
948 /* to notify */
949 fallthrough;
950 case ICMPV6_DEST_UNREACH:
951 case ICMPV6_TIME_EXCEED:
952 case ICMPV6_PARAMPROB:
953 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
954 break;
955
956 case NDISC_ROUTER_SOLICITATION:
957 case NDISC_ROUTER_ADVERTISEMENT:
958 case NDISC_NEIGHBOUR_SOLICITATION:
959 case NDISC_NEIGHBOUR_ADVERTISEMENT:
960 case NDISC_REDIRECT:
961 ndisc_rcv(skb);
962 break;
963
964 case ICMPV6_MGM_QUERY:
965 igmp6_event_query(skb);
966 return 0;
967
968 case ICMPV6_MGM_REPORT:
969 igmp6_event_report(skb);
970 return 0;
971
972 case ICMPV6_MGM_REDUCTION:
973 case ICMPV6_NI_QUERY:
974 case ICMPV6_NI_REPLY:
975 case ICMPV6_MLD2_REPORT:
976 case ICMPV6_DHAAD_REQUEST:
977 case ICMPV6_DHAAD_REPLY:
978 case ICMPV6_MOBILE_PREFIX_SOL:
979 case ICMPV6_MOBILE_PREFIX_ADV:
980 break;
981
982 default:
983 /* informational */
984 if (type & ICMPV6_INFOMSG_MASK)
985 break;
986
987 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n",
988 saddr, daddr);
989
990 /*
991 * error of unknown type.
992 * must pass to upper level
993 */
994
995 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu);
996 }
997
998 /* until the v6 path can be better sorted assume failure and
999 * preserve the status quo behaviour for the rest of the paths to here
1000 */
1001 if (success)
1002 consume_skb(skb);
1003 else
1004 kfree_skb(skb);
1005
1006 return 0;
1007
1008csum_error:
1009 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
1010discard_it:
1011 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
1012drop_no_count:
1013 kfree_skb(skb);
1014 return 0;
1015}
1016
1017void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
1018 u8 type,
1019 const struct in6_addr *saddr,
1020 const struct in6_addr *daddr,
1021 int oif)
1022{
1023 memset(fl6, 0, sizeof(*fl6));
1024 fl6->saddr = *saddr;
1025 fl6->daddr = *daddr;
1026 fl6->flowi6_proto = IPPROTO_ICMPV6;
1027 fl6->fl6_icmp_type = type;
1028 fl6->fl6_icmp_code = 0;
1029 fl6->flowi6_oif = oif;
1030 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
1031}
1032
1033static void __net_exit icmpv6_sk_exit(struct net *net)
1034{
1035 int i;
1036
1037 for_each_possible_cpu(i)
1038 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i));
1039 free_percpu(net->ipv6.icmp_sk);
1040}
1041
1042static int __net_init icmpv6_sk_init(struct net *net)
1043{
1044 struct sock *sk;
1045 int err, i;
1046
1047 net->ipv6.icmp_sk = alloc_percpu(struct sock *);
1048 if (!net->ipv6.icmp_sk)
1049 return -ENOMEM;
1050
1051 for_each_possible_cpu(i) {
1052 err = inet_ctl_sock_create(&sk, PF_INET6,
1053 SOCK_RAW, IPPROTO_ICMPV6, net);
1054 if (err < 0) {
1055 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
1056 err);
1057 goto fail;
1058 }
1059
1060 *per_cpu_ptr(net->ipv6.icmp_sk, i) = sk;
1061
1062 /* Enough space for 2 64K ICMP packets, including
1063 * sk_buff struct overhead.
1064 */
1065 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
1066 }
1067 return 0;
1068
1069 fail:
1070 icmpv6_sk_exit(net);
1071 return err;
1072}
1073
1074static struct pernet_operations icmpv6_sk_ops = {
1075 .init = icmpv6_sk_init,
1076 .exit = icmpv6_sk_exit,
1077};
1078
1079int __init icmpv6_init(void)
1080{
1081 int err;
1082
1083 err = register_pernet_subsys(&icmpv6_sk_ops);
1084 if (err < 0)
1085 return err;
1086
1087 err = -EAGAIN;
1088 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
1089 goto fail;
1090
1091 err = inet6_register_icmp_sender(icmp6_send);
1092 if (err)
1093 goto sender_reg_err;
1094 return 0;
1095
1096sender_reg_err:
1097 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1098fail:
1099 pr_err("Failed to register ICMP6 protocol\n");
1100 unregister_pernet_subsys(&icmpv6_sk_ops);
1101 return err;
1102}
1103
1104void icmpv6_cleanup(void)
1105{
1106 inet6_unregister_icmp_sender(icmp6_send);
1107 unregister_pernet_subsys(&icmpv6_sk_ops);
1108 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
1109}
1110
1111
1112static const struct icmp6_err {
1113 int err;
1114 int fatal;
1115} tab_unreach[] = {
1116 { /* NOROUTE */
1117 .err = ENETUNREACH,
1118 .fatal = 0,
1119 },
1120 { /* ADM_PROHIBITED */
1121 .err = EACCES,
1122 .fatal = 1,
1123 },
1124 { /* Was NOT_NEIGHBOUR, now reserved */
1125 .err = EHOSTUNREACH,
1126 .fatal = 0,
1127 },
1128 { /* ADDR_UNREACH */
1129 .err = EHOSTUNREACH,
1130 .fatal = 0,
1131 },
1132 { /* PORT_UNREACH */
1133 .err = ECONNREFUSED,
1134 .fatal = 1,
1135 },
1136 { /* POLICY_FAIL */
1137 .err = EACCES,
1138 .fatal = 1,
1139 },
1140 { /* REJECT_ROUTE */
1141 .err = EACCES,
1142 .fatal = 1,
1143 },
1144};
1145
1146int icmpv6_err_convert(u8 type, u8 code, int *err)
1147{
1148 int fatal = 0;
1149
1150 *err = EPROTO;
1151
1152 switch (type) {
1153 case ICMPV6_DEST_UNREACH:
1154 fatal = 1;
1155 if (code < ARRAY_SIZE(tab_unreach)) {
1156 *err = tab_unreach[code].err;
1157 fatal = tab_unreach[code].fatal;
1158 }
1159 break;
1160
1161 case ICMPV6_PKT_TOOBIG:
1162 *err = EMSGSIZE;
1163 break;
1164
1165 case ICMPV6_PARAMPROB:
1166 *err = EPROTO;
1167 fatal = 1;
1168 break;
1169
1170 case ICMPV6_TIME_EXCEED:
1171 *err = EHOSTUNREACH;
1172 break;
1173 }
1174
1175 return fatal;
1176}
1177EXPORT_SYMBOL(icmpv6_err_convert);
1178
1179#ifdef CONFIG_SYSCTL
1180static struct ctl_table ipv6_icmp_table_template[] = {
1181 {
1182 .procname = "ratelimit",
1183 .data = &init_net.ipv6.sysctl.icmpv6_time,
1184 .maxlen = sizeof(int),
1185 .mode = 0644,
1186 .proc_handler = proc_dointvec_ms_jiffies,
1187 },
1188 {
1189 .procname = "echo_ignore_all",
1190 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all,
1191 .maxlen = sizeof(u8),
1192 .mode = 0644,
1193 .proc_handler = proc_dou8vec_minmax,
1194 },
1195 {
1196 .procname = "echo_ignore_multicast",
1197 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
1198 .maxlen = sizeof(u8),
1199 .mode = 0644,
1200 .proc_handler = proc_dou8vec_minmax,
1201 },
1202 {
1203 .procname = "echo_ignore_anycast",
1204 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
1205 .maxlen = sizeof(u8),
1206 .mode = 0644,
1207 .proc_handler = proc_dou8vec_minmax,
1208 },
1209 {
1210 .procname = "ratemask",
1211 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr,
1212 .maxlen = ICMPV6_MSG_MAX + 1,
1213 .mode = 0644,
1214 .proc_handler = proc_do_large_bitmap,
1215 },
1216 { },
1217};
1218
1219struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
1220{
1221 struct ctl_table *table;
1222
1223 table = kmemdup(ipv6_icmp_table_template,
1224 sizeof(ipv6_icmp_table_template),
1225 GFP_KERNEL);
1226
1227 if (table) {
1228 table[0].data = &net->ipv6.sysctl.icmpv6_time;
1229 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all;
1230 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast;
1231 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast;
1232 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr;
1233 }
1234 return table;
1235}
1236#endif