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