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); 161 162 /* Based on RFC 8200, Section 4.5 Fragment Header, return 163 * false if this is a fragment packet with no icmp header info. 164 */ 165 if (!tp && frag_off != 0) 166 return false; 167 else if (!tp || !(*tp & ICMPV6_INFOMSG_MASK)) 168 return true; 169 } 170 return false; 171 } 172 173 static bool icmpv6_mask_allow(struct net *net, int type) 174 { 175 if (type > ICMPV6_MSG_MAX) 176 return true; 177 178 /* Limit if icmp type is set in ratemask. */ 179 if (!test_bit(type, net->ipv6.sysctl.icmpv6_ratemask)) 180 return true; 181 182 return false; 183 } 184 185 static bool icmpv6_global_allow(struct net *net, int type) 186 { 187 if (icmpv6_mask_allow(net, type)) 188 return true; 189 190 if (icmp_global_allow()) 191 return true; 192 193 return false; 194 } 195 196 /* 197 * Check the ICMP output rate limit 198 */ 199 static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, 200 struct flowi6 *fl6) 201 { 202 struct net *net = sock_net(sk); 203 struct dst_entry *dst; 204 bool res = false; 205 206 if (icmpv6_mask_allow(net, type)) 207 return true; 208 209 /* 210 * Look up the output route. 211 * XXX: perhaps the expire for routing entries cloned by 212 * this lookup should be more aggressive (not longer than timeout). 213 */ 214 dst = ip6_route_output(net, sk, fl6); 215 if (dst->error) { 216 IP6_INC_STATS(net, ip6_dst_idev(dst), 217 IPSTATS_MIB_OUTNOROUTES); 218 } else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) { 219 res = true; 220 } else { 221 struct rt6_info *rt = (struct rt6_info *)dst; 222 int tmo = net->ipv6.sysctl.icmpv6_time; 223 struct inet_peer *peer; 224 225 /* Give more bandwidth to wider prefixes. */ 226 if (rt->rt6i_dst.plen < 128) 227 tmo >>= ((128 - rt->rt6i_dst.plen)>>5); 228 229 peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr, 1); 230 res = inet_peer_xrlim_allow(peer, tmo); 231 if (peer) 232 inet_putpeer(peer); 233 } 234 dst_release(dst); 235 return res; 236 } 237 238 static bool icmpv6_rt_has_prefsrc(struct sock *sk, u8 type, 239 struct flowi6 *fl6) 240 { 241 struct net *net = sock_net(sk); 242 struct dst_entry *dst; 243 bool res = false; 244 245 dst = ip6_route_output(net, sk, fl6); 246 if (!dst->error) { 247 struct rt6_info *rt = (struct rt6_info *)dst; 248 struct in6_addr prefsrc; 249 250 rt6_get_prefsrc(rt, &prefsrc); 251 res = !ipv6_addr_any(&prefsrc); 252 } 253 dst_release(dst); 254 return res; 255 } 256 257 /* 258 * an inline helper for the "simple" if statement below 259 * checks if parameter problem report is caused by an 260 * unrecognized IPv6 option that has the Option Type 261 * highest-order two bits set to 10 262 */ 263 264 static bool opt_unrec(struct sk_buff *skb, __u32 offset) 265 { 266 u8 _optval, *op; 267 268 offset += skb_network_offset(skb); 269 op = skb_header_pointer(skb, offset, sizeof(_optval), &_optval); 270 if (!op) 271 return true; 272 return (*op & 0xC0) == 0x80; 273 } 274 275 void icmpv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6, 276 struct icmp6hdr *thdr, int len) 277 { 278 struct sk_buff *skb; 279 struct icmp6hdr *icmp6h; 280 281 skb = skb_peek(&sk->sk_write_queue); 282 if (!skb) 283 return; 284 285 icmp6h = icmp6_hdr(skb); 286 memcpy(icmp6h, thdr, sizeof(struct icmp6hdr)); 287 icmp6h->icmp6_cksum = 0; 288 289 if (skb_queue_len(&sk->sk_write_queue) == 1) { 290 skb->csum = csum_partial(icmp6h, 291 sizeof(struct icmp6hdr), skb->csum); 292 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 293 &fl6->daddr, 294 len, fl6->flowi6_proto, 295 skb->csum); 296 } else { 297 __wsum tmp_csum = 0; 298 299 skb_queue_walk(&sk->sk_write_queue, skb) { 300 tmp_csum = csum_add(tmp_csum, skb->csum); 301 } 302 303 tmp_csum = csum_partial(icmp6h, 304 sizeof(struct icmp6hdr), tmp_csum); 305 icmp6h->icmp6_cksum = csum_ipv6_magic(&fl6->saddr, 306 &fl6->daddr, 307 len, fl6->flowi6_proto, 308 tmp_csum); 309 } 310 ip6_push_pending_frames(sk); 311 } 312 313 struct icmpv6_msg { 314 struct sk_buff *skb; 315 int offset; 316 uint8_t type; 317 }; 318 319 static int icmpv6_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) 320 { 321 struct icmpv6_msg *msg = (struct icmpv6_msg *) from; 322 struct sk_buff *org_skb = msg->skb; 323 __wsum csum; 324 325 csum = skb_copy_and_csum_bits(org_skb, msg->offset + offset, 326 to, len); 327 skb->csum = csum_block_add(skb->csum, csum, odd); 328 if (!(msg->type & ICMPV6_INFOMSG_MASK)) 329 nf_ct_attach(skb, org_skb); 330 return 0; 331 } 332 333 #if IS_ENABLED(CONFIG_IPV6_MIP6) 334 static void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) 335 { 336 struct ipv6hdr *iph = ipv6_hdr(skb); 337 struct ipv6_destopt_hao *hao; 338 struct in6_addr tmp; 339 int off; 340 341 if (opt->dsthao) { 342 off = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 343 if (likely(off >= 0)) { 344 hao = (struct ipv6_destopt_hao *) 345 (skb_network_header(skb) + off); 346 tmp = iph->saddr; 347 iph->saddr = hao->addr; 348 hao->addr = tmp; 349 } 350 } 351 } 352 #else 353 static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {} 354 #endif 355 356 static struct dst_entry *icmpv6_route_lookup(struct net *net, 357 struct sk_buff *skb, 358 struct sock *sk, 359 struct flowi6 *fl6) 360 { 361 struct dst_entry *dst, *dst2; 362 struct flowi6 fl2; 363 int err; 364 365 err = ip6_dst_lookup(net, sk, &dst, fl6); 366 if (err) 367 return ERR_PTR(err); 368 369 /* 370 * We won't send icmp if the destination is known 371 * anycast. 372 */ 373 if (ipv6_anycast_destination(dst, &fl6->daddr)) { 374 net_dbg_ratelimited("icmp6_send: acast source\n"); 375 dst_release(dst); 376 return ERR_PTR(-EINVAL); 377 } 378 379 /* No need to clone since we're just using its address. */ 380 dst2 = dst; 381 382 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 383 if (!IS_ERR(dst)) { 384 if (dst != dst2) 385 return dst; 386 } else { 387 if (PTR_ERR(dst) == -EPERM) 388 dst = NULL; 389 else 390 return dst; 391 } 392 393 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 394 if (err) 395 goto relookup_failed; 396 397 err = ip6_dst_lookup(net, sk, &dst2, &fl2); 398 if (err) 399 goto relookup_failed; 400 401 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 402 if (!IS_ERR(dst2)) { 403 dst_release(dst); 404 dst = dst2; 405 } else { 406 err = PTR_ERR(dst2); 407 if (err == -EPERM) { 408 dst_release(dst); 409 return dst2; 410 } else 411 goto relookup_failed; 412 } 413 414 relookup_failed: 415 if (dst) 416 return dst; 417 return ERR_PTR(err); 418 } 419 420 static struct net_device *icmp6_dev(const struct sk_buff *skb) 421 { 422 struct net_device *dev = skb->dev; 423 424 /* for local traffic to local address, skb dev is the loopback 425 * device. Check if there is a dst attached to the skb and if so 426 * get the real device index. Same is needed for replies to a link 427 * local address on a device enslaved to an L3 master device 428 */ 429 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) { 430 const struct rt6_info *rt6 = skb_rt6_info(skb); 431 432 if (rt6) 433 dev = rt6->rt6i_idev->dev; 434 } 435 436 return dev; 437 } 438 439 static int icmp6_iif(const struct sk_buff *skb) 440 { 441 return icmp6_dev(skb)->ifindex; 442 } 443 444 /* 445 * Send an ICMP message in response to a packet in error 446 */ 447 void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, 448 const struct in6_addr *force_saddr, 449 const struct inet6_skb_parm *parm) 450 { 451 struct inet6_dev *idev = NULL; 452 struct ipv6hdr *hdr = ipv6_hdr(skb); 453 struct sock *sk; 454 struct net *net; 455 struct ipv6_pinfo *np; 456 const struct in6_addr *saddr = NULL; 457 struct dst_entry *dst; 458 struct icmp6hdr tmp_hdr; 459 struct flowi6 fl6; 460 struct icmpv6_msg msg; 461 struct ipcm6_cookie ipc6; 462 int iif = 0; 463 int addr_type = 0; 464 int len; 465 u32 mark; 466 467 if ((u8 *)hdr < skb->head || 468 (skb_network_header(skb) + sizeof(*hdr)) > skb_tail_pointer(skb)) 469 return; 470 471 if (!skb->dev) 472 return; 473 net = dev_net(skb->dev); 474 mark = IP6_REPLY_MARK(net, skb->mark); 475 /* 476 * Make sure we respect the rules 477 * i.e. RFC 1885 2.4(e) 478 * Rule (e.1) is enforced by not using icmp6_send 479 * in any code that processes icmp errors. 480 */ 481 addr_type = ipv6_addr_type(&hdr->daddr); 482 483 if (ipv6_chk_addr(net, &hdr->daddr, skb->dev, 0) || 484 ipv6_chk_acast_addr_src(net, skb->dev, &hdr->daddr)) 485 saddr = &hdr->daddr; 486 487 /* 488 * Dest addr check 489 */ 490 491 if (addr_type & IPV6_ADDR_MULTICAST || skb->pkt_type != PACKET_HOST) { 492 if (type != ICMPV6_PKT_TOOBIG && 493 !(type == ICMPV6_PARAMPROB && 494 code == ICMPV6_UNK_OPTION && 495 (opt_unrec(skb, info)))) 496 return; 497 498 saddr = NULL; 499 } 500 501 addr_type = ipv6_addr_type(&hdr->saddr); 502 503 /* 504 * Source addr check 505 */ 506 507 if (__ipv6_addr_needs_scope_id(addr_type)) { 508 iif = icmp6_iif(skb); 509 } else { 510 /* 511 * The source device is used for looking up which routing table 512 * to use for sending an ICMP error. 513 */ 514 iif = l3mdev_master_ifindex(skb->dev); 515 } 516 517 /* 518 * Must not send error if the source does not uniquely 519 * identify a single node (RFC2463 Section 2.4). 520 * We check unspecified / multicast addresses here, 521 * and anycast addresses will be checked later. 522 */ 523 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 524 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", 525 &hdr->saddr, &hdr->daddr); 526 return; 527 } 528 529 /* 530 * Never answer to a ICMP packet. 531 */ 532 if (is_ineligible(skb)) { 533 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", 534 &hdr->saddr, &hdr->daddr); 535 return; 536 } 537 538 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ 539 local_bh_disable(); 540 541 /* Check global sysctl_icmp_msgs_per_sec ratelimit */ 542 if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) 543 goto out_bh_enable; 544 545 mip6_addr_swap(skb, parm); 546 547 sk = icmpv6_xmit_lock(net); 548 if (!sk) 549 goto out_bh_enable; 550 551 memset(&fl6, 0, sizeof(fl6)); 552 fl6.flowi6_proto = IPPROTO_ICMPV6; 553 fl6.daddr = hdr->saddr; 554 if (force_saddr) 555 saddr = force_saddr; 556 if (saddr) { 557 fl6.saddr = *saddr; 558 } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) { 559 /* select a more meaningful saddr from input if */ 560 struct net_device *in_netdev; 561 562 in_netdev = dev_get_by_index(net, parm->iif); 563 if (in_netdev) { 564 ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr, 565 inet6_sk(sk)->srcprefs, 566 &fl6.saddr); 567 dev_put(in_netdev); 568 } 569 } 570 fl6.flowi6_mark = mark; 571 fl6.flowi6_oif = iif; 572 fl6.fl6_icmp_type = type; 573 fl6.fl6_icmp_code = code; 574 fl6.flowi6_uid = sock_net_uid(net, NULL); 575 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL); 576 security_skb_classify_flow(skb, flowi6_to_flowi(&fl6)); 577 578 np = inet6_sk(sk); 579 580 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 581 goto out; 582 583 tmp_hdr.icmp6_type = type; 584 tmp_hdr.icmp6_code = code; 585 tmp_hdr.icmp6_cksum = 0; 586 tmp_hdr.icmp6_pointer = htonl(info); 587 588 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 589 fl6.flowi6_oif = np->mcast_oif; 590 else if (!fl6.flowi6_oif) 591 fl6.flowi6_oif = np->ucast_oif; 592 593 ipcm6_init_sk(&ipc6, np); 594 ipc6.sockc.mark = mark; 595 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 596 597 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 598 if (IS_ERR(dst)) 599 goto out; 600 601 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 602 603 msg.skb = skb; 604 msg.offset = skb_network_offset(skb); 605 msg.type = type; 606 607 len = skb->len - msg.offset; 608 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 609 if (len < 0) { 610 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 611 &hdr->saddr, &hdr->daddr); 612 goto out_dst_release; 613 } 614 615 rcu_read_lock(); 616 idev = __in6_dev_get(skb->dev); 617 618 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 619 len + sizeof(struct icmp6hdr), 620 sizeof(struct icmp6hdr), 621 &ipc6, &fl6, (struct rt6_info *)dst, 622 MSG_DONTWAIT)) { 623 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 624 ip6_flush_pending_frames(sk); 625 } else { 626 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 627 len + sizeof(struct icmp6hdr)); 628 } 629 rcu_read_unlock(); 630 out_dst_release: 631 dst_release(dst); 632 out: 633 icmpv6_xmit_unlock(sk); 634 out_bh_enable: 635 local_bh_enable(); 636 } 637 EXPORT_SYMBOL(icmp6_send); 638 639 /* Slightly more convenient version of icmp6_send. 640 */ 641 void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos) 642 { 643 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb)); 644 kfree_skb(skb); 645 } 646 647 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH 648 * if sufficient data bytes are available 649 * @nhs is the size of the tunnel header(s) : 650 * Either an IPv4 header for SIT encap 651 * an IPv4 header + GRE header for GRE encap 652 */ 653 int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type, 654 unsigned int data_len) 655 { 656 struct in6_addr temp_saddr; 657 struct rt6_info *rt; 658 struct sk_buff *skb2; 659 u32 info = 0; 660 661 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8)) 662 return 1; 663 664 /* RFC 4884 (partial) support for ICMP extensions */ 665 if (data_len < 128 || (data_len & 7) || skb->len < data_len) 666 data_len = 0; 667 668 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC); 669 670 if (!skb2) 671 return 1; 672 673 skb_dst_drop(skb2); 674 skb_pull(skb2, nhs); 675 skb_reset_network_header(skb2); 676 677 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 678 skb, 0); 679 680 if (rt && rt->dst.dev) 681 skb2->dev = rt->dst.dev; 682 683 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr); 684 685 if (data_len) { 686 /* RFC 4884 (partial) support : 687 * insert 0 padding at the end, before the extensions 688 */ 689 __skb_push(skb2, nhs); 690 skb_reset_network_header(skb2); 691 memmove(skb2->data, skb2->data + nhs, data_len - nhs); 692 memset(skb2->data + data_len - nhs, 0, nhs); 693 /* RFC 4884 4.5 : Length is measured in 64-bit words, 694 * and stored in reserved[0] 695 */ 696 info = (data_len/8) << 24; 697 } 698 if (type == ICMP_TIME_EXCEEDED) 699 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 700 info, &temp_saddr, IP6CB(skb2)); 701 else 702 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 703 info, &temp_saddr, IP6CB(skb2)); 704 if (rt) 705 ip6_rt_put(rt); 706 707 kfree_skb(skb2); 708 709 return 0; 710 } 711 EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach); 712 713 static void icmpv6_echo_reply(struct sk_buff *skb) 714 { 715 struct net *net = dev_net(skb->dev); 716 struct sock *sk; 717 struct inet6_dev *idev; 718 struct ipv6_pinfo *np; 719 const struct in6_addr *saddr = NULL; 720 struct icmp6hdr *icmph = icmp6_hdr(skb); 721 struct icmp6hdr tmp_hdr; 722 struct flowi6 fl6; 723 struct icmpv6_msg msg; 724 struct dst_entry *dst; 725 struct ipcm6_cookie ipc6; 726 u32 mark = IP6_REPLY_MARK(net, skb->mark); 727 bool acast; 728 729 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) && 730 net->ipv6.sysctl.icmpv6_echo_ignore_multicast) 731 return; 732 733 saddr = &ipv6_hdr(skb)->daddr; 734 735 acast = ipv6_anycast_destination(skb_dst(skb), saddr); 736 if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast) 737 return; 738 739 if (!ipv6_unicast_destination(skb) && 740 !(net->ipv6.sysctl.anycast_src_echo_reply && acast)) 741 saddr = NULL; 742 743 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 744 tmp_hdr.icmp6_type = ICMPV6_ECHO_REPLY; 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 = ICMPV6_ECHO_REPLY; 756 fl6.flowi6_mark = mark; 757 fl6.flowi6_uid = sock_net_uid(net, NULL); 758 security_skb_classify_flow(skb, flowi6_to_flowi(&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 = ICMPV6_ECHO_REPLY; 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 (ip6_append_data(sk, icmpv6_getfrag, &msg, 794 skb->len + sizeof(struct icmp6hdr), 795 sizeof(struct icmp6hdr), &ipc6, &fl6, 796 (struct rt6_info *)dst, MSG_DONTWAIT)) { 797 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 798 ip6_flush_pending_frames(sk); 799 } else { 800 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 801 skb->len + sizeof(struct icmp6hdr)); 802 } 803 out_dst_release: 804 dst_release(dst); 805 out: 806 icmpv6_xmit_unlock(sk); 807 out_bh_enable: 808 local_bh_enable(); 809 } 810 811 void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info) 812 { 813 const struct inet6_protocol *ipprot; 814 int inner_offset; 815 __be16 frag_off; 816 u8 nexthdr; 817 struct net *net = dev_net(skb->dev); 818 819 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 820 goto out; 821 822 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 823 if (ipv6_ext_hdr(nexthdr)) { 824 /* now skip over extension headers */ 825 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 826 &nexthdr, &frag_off); 827 if (inner_offset < 0) 828 goto out; 829 } else { 830 inner_offset = sizeof(struct ipv6hdr); 831 } 832 833 /* Checkin header including 8 bytes of inner protocol header. */ 834 if (!pskb_may_pull(skb, inner_offset+8)) 835 goto out; 836 837 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 838 Without this we will not able f.e. to make source routed 839 pmtu discovery. 840 Corresponding argument (opt) to notifiers is already added. 841 --ANK (980726) 842 */ 843 844 ipprot = rcu_dereference(inet6_protos[nexthdr]); 845 if (ipprot && ipprot->err_handler) 846 ipprot->err_handler(skb, NULL, type, code, inner_offset, info); 847 848 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 849 return; 850 851 out: 852 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 853 } 854 855 /* 856 * Handle icmp messages 857 */ 858 859 static int icmpv6_rcv(struct sk_buff *skb) 860 { 861 struct net *net = dev_net(skb->dev); 862 struct net_device *dev = icmp6_dev(skb); 863 struct inet6_dev *idev = __in6_dev_get(dev); 864 const struct in6_addr *saddr, *daddr; 865 struct icmp6hdr *hdr; 866 u8 type; 867 bool success = false; 868 869 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 870 struct sec_path *sp = skb_sec_path(skb); 871 int nh; 872 873 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 874 XFRM_STATE_ICMP)) 875 goto drop_no_count; 876 877 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 878 goto drop_no_count; 879 880 nh = skb_network_offset(skb); 881 skb_set_network_header(skb, sizeof(*hdr)); 882 883 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb)) 884 goto drop_no_count; 885 886 skb_set_network_header(skb, nh); 887 } 888 889 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 890 891 saddr = &ipv6_hdr(skb)->saddr; 892 daddr = &ipv6_hdr(skb)->daddr; 893 894 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 895 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 896 saddr, daddr); 897 goto csum_error; 898 } 899 900 if (!pskb_pull(skb, sizeof(*hdr))) 901 goto discard_it; 902 903 hdr = icmp6_hdr(skb); 904 905 type = hdr->icmp6_type; 906 907 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 908 909 switch (type) { 910 case ICMPV6_ECHO_REQUEST: 911 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) 912 icmpv6_echo_reply(skb); 913 break; 914 915 case ICMPV6_ECHO_REPLY: 916 success = ping_rcv(skb); 917 break; 918 919 case ICMPV6_PKT_TOOBIG: 920 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 921 standard destination cache. Seems, only "advanced" 922 destination cache will allow to solve this problem 923 --ANK (980726) 924 */ 925 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 926 goto discard_it; 927 hdr = icmp6_hdr(skb); 928 929 /* to notify */ 930 fallthrough; 931 case ICMPV6_DEST_UNREACH: 932 case ICMPV6_TIME_EXCEED: 933 case ICMPV6_PARAMPROB: 934 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 935 break; 936 937 case NDISC_ROUTER_SOLICITATION: 938 case NDISC_ROUTER_ADVERTISEMENT: 939 case NDISC_NEIGHBOUR_SOLICITATION: 940 case NDISC_NEIGHBOUR_ADVERTISEMENT: 941 case NDISC_REDIRECT: 942 ndisc_rcv(skb); 943 break; 944 945 case ICMPV6_MGM_QUERY: 946 igmp6_event_query(skb); 947 break; 948 949 case ICMPV6_MGM_REPORT: 950 igmp6_event_report(skb); 951 break; 952 953 case ICMPV6_MGM_REDUCTION: 954 case ICMPV6_NI_QUERY: 955 case ICMPV6_NI_REPLY: 956 case ICMPV6_MLD2_REPORT: 957 case ICMPV6_DHAAD_REQUEST: 958 case ICMPV6_DHAAD_REPLY: 959 case ICMPV6_MOBILE_PREFIX_SOL: 960 case ICMPV6_MOBILE_PREFIX_ADV: 961 break; 962 963 default: 964 /* informational */ 965 if (type & ICMPV6_INFOMSG_MASK) 966 break; 967 968 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 969 saddr, daddr); 970 971 /* 972 * error of unknown type. 973 * must pass to upper level 974 */ 975 976 icmpv6_notify(skb, type, hdr->icmp6_code, hdr->icmp6_mtu); 977 } 978 979 /* until the v6 path can be better sorted assume failure and 980 * preserve the status quo behaviour for the rest of the paths to here 981 */ 982 if (success) 983 consume_skb(skb); 984 else 985 kfree_skb(skb); 986 987 return 0; 988 989 csum_error: 990 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 991 discard_it: 992 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 993 drop_no_count: 994 kfree_skb(skb); 995 return 0; 996 } 997 998 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 999 u8 type, 1000 const struct in6_addr *saddr, 1001 const struct in6_addr *daddr, 1002 int oif) 1003 { 1004 memset(fl6, 0, sizeof(*fl6)); 1005 fl6->saddr = *saddr; 1006 fl6->daddr = *daddr; 1007 fl6->flowi6_proto = IPPROTO_ICMPV6; 1008 fl6->fl6_icmp_type = type; 1009 fl6->fl6_icmp_code = 0; 1010 fl6->flowi6_oif = oif; 1011 security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); 1012 } 1013 1014 static void __net_exit icmpv6_sk_exit(struct net *net) 1015 { 1016 int i; 1017 1018 for_each_possible_cpu(i) 1019 inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i)); 1020 free_percpu(net->ipv6.icmp_sk); 1021 } 1022 1023 static int __net_init icmpv6_sk_init(struct net *net) 1024 { 1025 struct sock *sk; 1026 int err, i; 1027 1028 net->ipv6.icmp_sk = alloc_percpu(struct sock *); 1029 if (!net->ipv6.icmp_sk) 1030 return -ENOMEM; 1031 1032 for_each_possible_cpu(i) { 1033 err = inet_ctl_sock_create(&sk, PF_INET6, 1034 SOCK_RAW, IPPROTO_ICMPV6, net); 1035 if (err < 0) { 1036 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 1037 err); 1038 goto fail; 1039 } 1040 1041 *per_cpu_ptr(net->ipv6.icmp_sk, i) = sk; 1042 1043 /* Enough space for 2 64K ICMP packets, including 1044 * sk_buff struct overhead. 1045 */ 1046 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 1047 } 1048 return 0; 1049 1050 fail: 1051 icmpv6_sk_exit(net); 1052 return err; 1053 } 1054 1055 static struct pernet_operations icmpv6_sk_ops = { 1056 .init = icmpv6_sk_init, 1057 .exit = icmpv6_sk_exit, 1058 }; 1059 1060 int __init icmpv6_init(void) 1061 { 1062 int err; 1063 1064 err = register_pernet_subsys(&icmpv6_sk_ops); 1065 if (err < 0) 1066 return err; 1067 1068 err = -EAGAIN; 1069 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 1070 goto fail; 1071 1072 err = inet6_register_icmp_sender(icmp6_send); 1073 if (err) 1074 goto sender_reg_err; 1075 return 0; 1076 1077 sender_reg_err: 1078 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1079 fail: 1080 pr_err("Failed to register ICMP6 protocol\n"); 1081 unregister_pernet_subsys(&icmpv6_sk_ops); 1082 return err; 1083 } 1084 1085 void icmpv6_cleanup(void) 1086 { 1087 inet6_unregister_icmp_sender(icmp6_send); 1088 unregister_pernet_subsys(&icmpv6_sk_ops); 1089 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1090 } 1091 1092 1093 static const struct icmp6_err { 1094 int err; 1095 int fatal; 1096 } tab_unreach[] = { 1097 { /* NOROUTE */ 1098 .err = ENETUNREACH, 1099 .fatal = 0, 1100 }, 1101 { /* ADM_PROHIBITED */ 1102 .err = EACCES, 1103 .fatal = 1, 1104 }, 1105 { /* Was NOT_NEIGHBOUR, now reserved */ 1106 .err = EHOSTUNREACH, 1107 .fatal = 0, 1108 }, 1109 { /* ADDR_UNREACH */ 1110 .err = EHOSTUNREACH, 1111 .fatal = 0, 1112 }, 1113 { /* PORT_UNREACH */ 1114 .err = ECONNREFUSED, 1115 .fatal = 1, 1116 }, 1117 { /* POLICY_FAIL */ 1118 .err = EACCES, 1119 .fatal = 1, 1120 }, 1121 { /* REJECT_ROUTE */ 1122 .err = EACCES, 1123 .fatal = 1, 1124 }, 1125 }; 1126 1127 int icmpv6_err_convert(u8 type, u8 code, int *err) 1128 { 1129 int fatal = 0; 1130 1131 *err = EPROTO; 1132 1133 switch (type) { 1134 case ICMPV6_DEST_UNREACH: 1135 fatal = 1; 1136 if (code < ARRAY_SIZE(tab_unreach)) { 1137 *err = tab_unreach[code].err; 1138 fatal = tab_unreach[code].fatal; 1139 } 1140 break; 1141 1142 case ICMPV6_PKT_TOOBIG: 1143 *err = EMSGSIZE; 1144 break; 1145 1146 case ICMPV6_PARAMPROB: 1147 *err = EPROTO; 1148 fatal = 1; 1149 break; 1150 1151 case ICMPV6_TIME_EXCEED: 1152 *err = EHOSTUNREACH; 1153 break; 1154 } 1155 1156 return fatal; 1157 } 1158 EXPORT_SYMBOL(icmpv6_err_convert); 1159 1160 #ifdef CONFIG_SYSCTL 1161 static struct ctl_table ipv6_icmp_table_template[] = { 1162 { 1163 .procname = "ratelimit", 1164 .data = &init_net.ipv6.sysctl.icmpv6_time, 1165 .maxlen = sizeof(int), 1166 .mode = 0644, 1167 .proc_handler = proc_dointvec_ms_jiffies, 1168 }, 1169 { 1170 .procname = "echo_ignore_all", 1171 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, 1172 .maxlen = sizeof(int), 1173 .mode = 0644, 1174 .proc_handler = proc_dointvec, 1175 }, 1176 { 1177 .procname = "echo_ignore_multicast", 1178 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast, 1179 .maxlen = sizeof(int), 1180 .mode = 0644, 1181 .proc_handler = proc_dointvec, 1182 }, 1183 { 1184 .procname = "echo_ignore_anycast", 1185 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast, 1186 .maxlen = sizeof(int), 1187 .mode = 0644, 1188 .proc_handler = proc_dointvec, 1189 }, 1190 { 1191 .procname = "ratemask", 1192 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr, 1193 .maxlen = ICMPV6_MSG_MAX + 1, 1194 .mode = 0644, 1195 .proc_handler = proc_do_large_bitmap, 1196 }, 1197 { }, 1198 }; 1199 1200 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1201 { 1202 struct ctl_table *table; 1203 1204 table = kmemdup(ipv6_icmp_table_template, 1205 sizeof(ipv6_icmp_table_template), 1206 GFP_KERNEL); 1207 1208 if (table) { 1209 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1210 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; 1211 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast; 1212 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast; 1213 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr; 1214 } 1215 return table; 1216 } 1217 #endif 1218