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