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 72 static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk); 73 74 static 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 94 static int icmpv6_rcv(struct sk_buff *skb); 95 96 static 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 */ 103 static 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 } 118 119 static 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 */ 135 136 static 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 } 165 166 static 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 } 177 178 static 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 */ 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 if (!res) 229 __ICMP6_INC_STATS(net, ip6_dst_idev(dst), 230 ICMP6_MIB_RATELIMITHOST); 231 dst_release(dst); 232 return res; 233 } 234 235 static 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 */ 260 261 static 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 } 271 272 void 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 } 309 310 struct icmpv6_msg { 311 struct sk_buff *skb; 312 int offset; 313 uint8_t type; 314 }; 315 316 static 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) 331 static 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 347 static inline void mip6_addr_swap(struct sk_buff *skb, const struct inet6_skb_parm *opt) {} 348 #endif 349 350 static 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. 366 */ 367 if (ipv6_anycast_destination(dst, &fl6->daddr)) { 368 net_dbg_ratelimited("icmp6_send: acast source\n"); 369 dst_release(dst); 370 return ERR_PTR(-EINVAL); 371 } 372 373 /* No need to clone since we're just using its address. */ 374 dst2 = dst; 375 376 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), sk, 0); 377 if (!IS_ERR(dst)) { 378 if (dst != dst2) 379 return dst; 380 } else { 381 if (PTR_ERR(dst) == -EPERM) 382 dst = NULL; 383 else 384 return dst; 385 } 386 387 err = xfrm_decode_session_reverse(skb, flowi6_to_flowi(&fl2), AF_INET6); 388 if (err) 389 goto relookup_failed; 390 391 err = ip6_dst_lookup(net, sk, &dst2, &fl2); 392 if (err) 393 goto relookup_failed; 394 395 dst2 = xfrm_lookup(net, dst2, flowi6_to_flowi(&fl2), sk, XFRM_LOOKUP_ICMP); 396 if (!IS_ERR(dst2)) { 397 dst_release(dst); 398 dst = dst2; 399 } else { 400 err = PTR_ERR(dst2); 401 if (err == -EPERM) { 402 dst_release(dst); 403 return dst2; 404 } else 405 goto relookup_failed; 406 } 407 408 relookup_failed: 409 if (dst) 410 return dst; 411 return ERR_PTR(err); 412 } 413 414 static struct net_device *icmp6_dev(const struct sk_buff *skb) 415 { 416 struct net_device *dev = skb->dev; 417 418 /* for local traffic to local address, skb dev is the loopback 419 * device. Check if there is a dst attached to the skb and if so 420 * get the real device index. Same is needed for replies to a link 421 * local address on a device enslaved to an L3 master device 422 */ 423 if (unlikely(dev->ifindex == LOOPBACK_IFINDEX || netif_is_l3_master(skb->dev))) { 424 const struct rt6_info *rt6 = skb_rt6_info(skb); 425 426 if (rt6) 427 dev = rt6->rt6i_idev->dev; 428 } 429 430 return dev; 431 } 432 433 static int icmp6_iif(const struct sk_buff *skb) 434 { 435 return icmp6_dev(skb)->ifindex; 436 } 437 438 /* 439 * Send an ICMP message in response to a packet in error 440 */ 441 void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, 442 const struct in6_addr *force_saddr, 443 const struct inet6_skb_parm *parm) 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 /* 505 * The source device is used for looking up which routing table 506 * to use for sending an ICMP error. 507 */ 508 iif = l3mdev_master_ifindex(skb->dev); 509 } 510 511 /* 512 * Must not send error if the source does not uniquely 513 * identify a single node (RFC2463 Section 2.4). 514 * We check unspecified / multicast addresses here, 515 * and anycast addresses will be checked later. 516 */ 517 if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) { 518 net_dbg_ratelimited("icmp6_send: addr_any/mcast source [%pI6c > %pI6c]\n", 519 &hdr->saddr, &hdr->daddr); 520 return; 521 } 522 523 /* 524 * Never answer to a ICMP packet. 525 */ 526 if (is_ineligible(skb)) { 527 net_dbg_ratelimited("icmp6_send: no reply to icmp error [%pI6c > %pI6c]\n", 528 &hdr->saddr, &hdr->daddr); 529 return; 530 } 531 532 /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ 533 local_bh_disable(); 534 535 /* Check global sysctl_icmp_msgs_per_sec ratelimit */ 536 if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) 537 goto out_bh_enable; 538 539 mip6_addr_swap(skb, parm); 540 541 sk = icmpv6_xmit_lock(net); 542 if (!sk) 543 goto out_bh_enable; 544 545 memset(&fl6, 0, sizeof(fl6)); 546 fl6.flowi6_proto = IPPROTO_ICMPV6; 547 fl6.daddr = hdr->saddr; 548 if (force_saddr) 549 saddr = force_saddr; 550 if (saddr) { 551 fl6.saddr = *saddr; 552 } else if (!icmpv6_rt_has_prefsrc(sk, type, &fl6)) { 553 /* select a more meaningful saddr from input if */ 554 struct net_device *in_netdev; 555 556 in_netdev = dev_get_by_index(net, parm->iif); 557 if (in_netdev) { 558 ipv6_dev_get_saddr(net, in_netdev, &fl6.daddr, 559 inet6_sk(sk)->srcprefs, 560 &fl6.saddr); 561 dev_put(in_netdev); 562 } 563 } 564 fl6.flowi6_mark = mark; 565 fl6.flowi6_oif = iif; 566 fl6.fl6_icmp_type = type; 567 fl6.fl6_icmp_code = code; 568 fl6.flowi6_uid = sock_net_uid(net, NULL); 569 fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL); 570 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6)); 571 572 np = inet6_sk(sk); 573 574 if (!icmpv6_xrlim_allow(sk, type, &fl6)) 575 goto out; 576 577 tmp_hdr.icmp6_type = type; 578 tmp_hdr.icmp6_code = code; 579 tmp_hdr.icmp6_cksum = 0; 580 tmp_hdr.icmp6_pointer = htonl(info); 581 582 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 583 fl6.flowi6_oif = np->mcast_oif; 584 else if (!fl6.flowi6_oif) 585 fl6.flowi6_oif = np->ucast_oif; 586 587 ipcm6_init_sk(&ipc6, np); 588 ipc6.sockc.mark = mark; 589 fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel); 590 591 dst = icmpv6_route_lookup(net, skb, sk, &fl6); 592 if (IS_ERR(dst)) 593 goto out; 594 595 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 596 597 msg.skb = skb; 598 msg.offset = skb_network_offset(skb); 599 msg.type = type; 600 601 len = skb->len - msg.offset; 602 len = min_t(unsigned int, len, IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(struct icmp6hdr)); 603 if (len < 0) { 604 net_dbg_ratelimited("icmp: len problem [%pI6c > %pI6c]\n", 605 &hdr->saddr, &hdr->daddr); 606 goto out_dst_release; 607 } 608 609 rcu_read_lock(); 610 idev = __in6_dev_get(skb->dev); 611 612 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 613 len + sizeof(struct icmp6hdr), 614 sizeof(struct icmp6hdr), 615 &ipc6, &fl6, (struct rt6_info *)dst, 616 MSG_DONTWAIT)) { 617 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 618 ip6_flush_pending_frames(sk); 619 } else { 620 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 621 len + sizeof(struct icmp6hdr)); 622 } 623 rcu_read_unlock(); 624 out_dst_release: 625 dst_release(dst); 626 out: 627 icmpv6_xmit_unlock(sk); 628 out_bh_enable: 629 local_bh_enable(); 630 } 631 EXPORT_SYMBOL(icmp6_send); 632 633 /* Slightly more convenient version of icmp6_send with drop reasons. 634 */ 635 void icmpv6_param_prob_reason(struct sk_buff *skb, u8 code, int pos, 636 enum skb_drop_reason reason) 637 { 638 icmp6_send(skb, ICMPV6_PARAMPROB, code, pos, NULL, IP6CB(skb)); 639 kfree_skb_reason(skb, reason); 640 } 641 642 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH 643 * if sufficient data bytes are available 644 * @nhs is the size of the tunnel header(s) : 645 * Either an IPv4 header for SIT encap 646 * an IPv4 header + GRE header for GRE encap 647 */ 648 int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type, 649 unsigned int data_len) 650 { 651 struct in6_addr temp_saddr; 652 struct rt6_info *rt; 653 struct sk_buff *skb2; 654 u32 info = 0; 655 656 if (!pskb_may_pull(skb, nhs + sizeof(struct ipv6hdr) + 8)) 657 return 1; 658 659 /* RFC 4884 (partial) support for ICMP extensions */ 660 if (data_len < 128 || (data_len & 7) || skb->len < data_len) 661 data_len = 0; 662 663 skb2 = data_len ? skb_copy(skb, GFP_ATOMIC) : skb_clone(skb, GFP_ATOMIC); 664 665 if (!skb2) 666 return 1; 667 668 skb_dst_drop(skb2); 669 skb_pull(skb2, nhs); 670 skb_reset_network_header(skb2); 671 672 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 673 skb, 0); 674 675 if (rt && rt->dst.dev) 676 skb2->dev = rt->dst.dev; 677 678 ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr, &temp_saddr); 679 680 if (data_len) { 681 /* RFC 4884 (partial) support : 682 * insert 0 padding at the end, before the extensions 683 */ 684 __skb_push(skb2, nhs); 685 skb_reset_network_header(skb2); 686 memmove(skb2->data, skb2->data + nhs, data_len - nhs); 687 memset(skb2->data + data_len - nhs, 0, nhs); 688 /* RFC 4884 4.5 : Length is measured in 64-bit words, 689 * and stored in reserved[0] 690 */ 691 info = (data_len/8) << 24; 692 } 693 if (type == ICMP_TIME_EXCEEDED) 694 icmp6_send(skb2, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 695 info, &temp_saddr, IP6CB(skb2)); 696 else 697 icmp6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 698 info, &temp_saddr, IP6CB(skb2)); 699 if (rt) 700 ip6_rt_put(rt); 701 702 kfree_skb(skb2); 703 704 return 0; 705 } 706 EXPORT_SYMBOL(ip6_err_gen_icmpv6_unreach); 707 708 static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) 709 { 710 struct net *net = dev_net(skb->dev); 711 struct sock *sk; 712 struct inet6_dev *idev; 713 struct ipv6_pinfo *np; 714 const struct in6_addr *saddr = NULL; 715 struct icmp6hdr *icmph = icmp6_hdr(skb); 716 struct icmp6hdr tmp_hdr; 717 struct flowi6 fl6; 718 struct icmpv6_msg msg; 719 struct dst_entry *dst; 720 struct ipcm6_cookie ipc6; 721 u32 mark = IP6_REPLY_MARK(net, skb->mark); 722 SKB_DR(reason); 723 bool acast; 724 u8 type; 725 726 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) && 727 net->ipv6.sysctl.icmpv6_echo_ignore_multicast) 728 return reason; 729 730 saddr = &ipv6_hdr(skb)->daddr; 731 732 acast = ipv6_anycast_destination(skb_dst(skb), saddr); 733 if (acast && net->ipv6.sysctl.icmpv6_echo_ignore_anycast) 734 return reason; 735 736 if (!ipv6_unicast_destination(skb) && 737 !(net->ipv6.sysctl.anycast_src_echo_reply && acast)) 738 saddr = NULL; 739 740 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST) 741 type = ICMPV6_EXT_ECHO_REPLY; 742 else 743 type = ICMPV6_ECHO_REPLY; 744 745 memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr)); 746 tmp_hdr.icmp6_type = type; 747 748 memset(&fl6, 0, sizeof(fl6)); 749 if (net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ICMPV6_ECHO_REPLIES) 750 fl6.flowlabel = ip6_flowlabel(ipv6_hdr(skb)); 751 752 fl6.flowi6_proto = IPPROTO_ICMPV6; 753 fl6.daddr = ipv6_hdr(skb)->saddr; 754 if (saddr) 755 fl6.saddr = *saddr; 756 fl6.flowi6_oif = icmp6_iif(skb); 757 fl6.fl6_icmp_type = type; 758 fl6.flowi6_mark = mark; 759 fl6.flowi6_uid = sock_net_uid(net, NULL); 760 security_skb_classify_flow(skb, flowi6_to_flowi_common(&fl6)); 761 762 local_bh_disable(); 763 sk = icmpv6_xmit_lock(net); 764 if (!sk) 765 goto out_bh_enable; 766 np = inet6_sk(sk); 767 768 if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr)) 769 fl6.flowi6_oif = np->mcast_oif; 770 else if (!fl6.flowi6_oif) 771 fl6.flowi6_oif = np->ucast_oif; 772 773 if (ip6_dst_lookup(net, sk, &dst, &fl6)) 774 goto out; 775 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0); 776 if (IS_ERR(dst)) 777 goto out; 778 779 /* Check the ratelimit */ 780 if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) || 781 !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) 782 goto out_dst_release; 783 784 idev = __in6_dev_get(skb->dev); 785 786 msg.skb = skb; 787 msg.offset = 0; 788 msg.type = type; 789 790 ipcm6_init_sk(&ipc6, np); 791 ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst); 792 ipc6.tclass = ipv6_get_dsfield(ipv6_hdr(skb)); 793 ipc6.sockc.mark = mark; 794 795 if (icmph->icmp6_type == ICMPV6_EXT_ECHO_REQUEST) 796 if (!icmp_build_probe(skb, (struct icmphdr *)&tmp_hdr)) 797 goto out_dst_release; 798 799 if (ip6_append_data(sk, icmpv6_getfrag, &msg, 800 skb->len + sizeof(struct icmp6hdr), 801 sizeof(struct icmp6hdr), &ipc6, &fl6, 802 (struct rt6_info *)dst, MSG_DONTWAIT)) { 803 __ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTERRORS); 804 ip6_flush_pending_frames(sk); 805 } else { 806 icmpv6_push_pending_frames(sk, &fl6, &tmp_hdr, 807 skb->len + sizeof(struct icmp6hdr)); 808 reason = SKB_CONSUMED; 809 } 810 out_dst_release: 811 dst_release(dst); 812 out: 813 icmpv6_xmit_unlock(sk); 814 out_bh_enable: 815 local_bh_enable(); 816 return reason; 817 } 818 819 enum skb_drop_reason icmpv6_notify(struct sk_buff *skb, u8 type, 820 u8 code, __be32 info) 821 { 822 struct inet6_skb_parm *opt = IP6CB(skb); 823 struct net *net = dev_net(skb->dev); 824 const struct inet6_protocol *ipprot; 825 enum skb_drop_reason reason; 826 int inner_offset; 827 __be16 frag_off; 828 u8 nexthdr; 829 830 reason = pskb_may_pull_reason(skb, sizeof(struct ipv6hdr)); 831 if (reason != SKB_NOT_DROPPED_YET) 832 goto out; 833 834 seg6_icmp_srh(skb, opt); 835 836 nexthdr = ((struct ipv6hdr *)skb->data)->nexthdr; 837 if (ipv6_ext_hdr(nexthdr)) { 838 /* now skip over extension headers */ 839 inner_offset = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), 840 &nexthdr, &frag_off); 841 if (inner_offset < 0) { 842 SKB_DR_SET(reason, IPV6_BAD_EXTHDR); 843 goto out; 844 } 845 } else { 846 inner_offset = sizeof(struct ipv6hdr); 847 } 848 849 /* Checkin header including 8 bytes of inner protocol header. */ 850 reason = pskb_may_pull_reason(skb, inner_offset + 8); 851 if (reason != SKB_NOT_DROPPED_YET) 852 goto out; 853 854 /* BUGGG_FUTURE: we should try to parse exthdrs in this packet. 855 Without this we will not able f.e. to make source routed 856 pmtu discovery. 857 Corresponding argument (opt) to notifiers is already added. 858 --ANK (980726) 859 */ 860 861 ipprot = rcu_dereference(inet6_protos[nexthdr]); 862 if (ipprot && ipprot->err_handler) 863 ipprot->err_handler(skb, opt, type, code, inner_offset, info); 864 865 raw6_icmp_error(skb, nexthdr, type, code, inner_offset, info); 866 return SKB_CONSUMED; 867 868 out: 869 __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); 870 return reason; 871 } 872 873 /* 874 * Handle icmp messages 875 */ 876 877 static int icmpv6_rcv(struct sk_buff *skb) 878 { 879 enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED; 880 struct net *net = dev_net(skb->dev); 881 struct net_device *dev = icmp6_dev(skb); 882 struct inet6_dev *idev = __in6_dev_get(dev); 883 const struct in6_addr *saddr, *daddr; 884 struct icmp6hdr *hdr; 885 u8 type; 886 887 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { 888 struct sec_path *sp = skb_sec_path(skb); 889 int nh; 890 891 if (!(sp && sp->xvec[sp->len - 1]->props.flags & 892 XFRM_STATE_ICMP)) { 893 reason = SKB_DROP_REASON_XFRM_POLICY; 894 goto drop_no_count; 895 } 896 897 if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr))) 898 goto drop_no_count; 899 900 nh = skb_network_offset(skb); 901 skb_set_network_header(skb, sizeof(*hdr)); 902 903 if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, 904 skb)) { 905 reason = SKB_DROP_REASON_XFRM_POLICY; 906 goto drop_no_count; 907 } 908 909 skb_set_network_header(skb, nh); 910 } 911 912 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INMSGS); 913 914 saddr = &ipv6_hdr(skb)->saddr; 915 daddr = &ipv6_hdr(skb)->daddr; 916 917 if (skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo)) { 918 net_dbg_ratelimited("ICMPv6 checksum failed [%pI6c > %pI6c]\n", 919 saddr, daddr); 920 goto csum_error; 921 } 922 923 if (!pskb_pull(skb, sizeof(*hdr))) 924 goto discard_it; 925 926 hdr = icmp6_hdr(skb); 927 928 type = hdr->icmp6_type; 929 930 ICMP6MSGIN_INC_STATS(dev_net(dev), idev, type); 931 932 switch (type) { 933 case ICMPV6_ECHO_REQUEST: 934 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all) 935 reason = icmpv6_echo_reply(skb); 936 break; 937 case ICMPV6_EXT_ECHO_REQUEST: 938 if (!net->ipv6.sysctl.icmpv6_echo_ignore_all && 939 READ_ONCE(net->ipv4.sysctl_icmp_echo_enable_probe)) 940 reason = icmpv6_echo_reply(skb); 941 break; 942 943 case ICMPV6_ECHO_REPLY: 944 reason = ping_rcv(skb); 945 break; 946 947 case ICMPV6_EXT_ECHO_REPLY: 948 reason = ping_rcv(skb); 949 break; 950 951 case ICMPV6_PKT_TOOBIG: 952 /* BUGGG_FUTURE: if packet contains rthdr, we cannot update 953 standard destination cache. Seems, only "advanced" 954 destination cache will allow to solve this problem 955 --ANK (980726) 956 */ 957 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 958 goto discard_it; 959 hdr = icmp6_hdr(skb); 960 961 /* to notify */ 962 fallthrough; 963 case ICMPV6_DEST_UNREACH: 964 case ICMPV6_TIME_EXCEED: 965 case ICMPV6_PARAMPROB: 966 reason = icmpv6_notify(skb, type, hdr->icmp6_code, 967 hdr->icmp6_mtu); 968 break; 969 970 case NDISC_ROUTER_SOLICITATION: 971 case NDISC_ROUTER_ADVERTISEMENT: 972 case NDISC_NEIGHBOUR_SOLICITATION: 973 case NDISC_NEIGHBOUR_ADVERTISEMENT: 974 case NDISC_REDIRECT: 975 reason = ndisc_rcv(skb); 976 break; 977 978 case ICMPV6_MGM_QUERY: 979 igmp6_event_query(skb); 980 return 0; 981 982 case ICMPV6_MGM_REPORT: 983 igmp6_event_report(skb); 984 return 0; 985 986 case ICMPV6_MGM_REDUCTION: 987 case ICMPV6_NI_QUERY: 988 case ICMPV6_NI_REPLY: 989 case ICMPV6_MLD2_REPORT: 990 case ICMPV6_DHAAD_REQUEST: 991 case ICMPV6_DHAAD_REPLY: 992 case ICMPV6_MOBILE_PREFIX_SOL: 993 case ICMPV6_MOBILE_PREFIX_ADV: 994 break; 995 996 default: 997 /* informational */ 998 if (type & ICMPV6_INFOMSG_MASK) 999 break; 1000 1001 net_dbg_ratelimited("icmpv6: msg of unknown type [%pI6c > %pI6c]\n", 1002 saddr, daddr); 1003 1004 /* 1005 * error of unknown type. 1006 * must pass to upper level 1007 */ 1008 1009 reason = icmpv6_notify(skb, type, hdr->icmp6_code, 1010 hdr->icmp6_mtu); 1011 } 1012 1013 /* until the v6 path can be better sorted assume failure and 1014 * preserve the status quo behaviour for the rest of the paths to here 1015 */ 1016 if (reason) 1017 kfree_skb_reason(skb, reason); 1018 else 1019 consume_skb(skb); 1020 1021 return 0; 1022 1023 csum_error: 1024 reason = SKB_DROP_REASON_ICMP_CSUM; 1025 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS); 1026 discard_it: 1027 __ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS); 1028 drop_no_count: 1029 kfree_skb_reason(skb, reason); 1030 return 0; 1031 } 1032 1033 void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6, 1034 u8 type, 1035 const struct in6_addr *saddr, 1036 const struct in6_addr *daddr, 1037 int oif) 1038 { 1039 memset(fl6, 0, sizeof(*fl6)); 1040 fl6->saddr = *saddr; 1041 fl6->daddr = *daddr; 1042 fl6->flowi6_proto = IPPROTO_ICMPV6; 1043 fl6->fl6_icmp_type = type; 1044 fl6->fl6_icmp_code = 0; 1045 fl6->flowi6_oif = oif; 1046 security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6)); 1047 } 1048 1049 int __init icmpv6_init(void) 1050 { 1051 struct sock *sk; 1052 int err, i; 1053 1054 for_each_possible_cpu(i) { 1055 err = inet_ctl_sock_create(&sk, PF_INET6, 1056 SOCK_RAW, IPPROTO_ICMPV6, &init_net); 1057 if (err < 0) { 1058 pr_err("Failed to initialize the ICMP6 control socket (err %d)\n", 1059 err); 1060 return err; 1061 } 1062 1063 per_cpu(ipv6_icmp_sk, i) = sk; 1064 1065 /* Enough space for 2 64K ICMP packets, including 1066 * sk_buff struct overhead. 1067 */ 1068 sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024); 1069 } 1070 1071 err = -EAGAIN; 1072 if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0) 1073 goto fail; 1074 1075 err = inet6_register_icmp_sender(icmp6_send); 1076 if (err) 1077 goto sender_reg_err; 1078 return 0; 1079 1080 sender_reg_err: 1081 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1082 fail: 1083 pr_err("Failed to register ICMP6 protocol\n"); 1084 return err; 1085 } 1086 1087 void icmpv6_cleanup(void) 1088 { 1089 inet6_unregister_icmp_sender(icmp6_send); 1090 inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6); 1091 } 1092 1093 1094 static const struct icmp6_err { 1095 int err; 1096 int fatal; 1097 } tab_unreach[] = { 1098 { /* NOROUTE */ 1099 .err = ENETUNREACH, 1100 .fatal = 0, 1101 }, 1102 { /* ADM_PROHIBITED */ 1103 .err = EACCES, 1104 .fatal = 1, 1105 }, 1106 { /* Was NOT_NEIGHBOUR, now reserved */ 1107 .err = EHOSTUNREACH, 1108 .fatal = 0, 1109 }, 1110 { /* ADDR_UNREACH */ 1111 .err = EHOSTUNREACH, 1112 .fatal = 0, 1113 }, 1114 { /* PORT_UNREACH */ 1115 .err = ECONNREFUSED, 1116 .fatal = 1, 1117 }, 1118 { /* POLICY_FAIL */ 1119 .err = EACCES, 1120 .fatal = 1, 1121 }, 1122 { /* REJECT_ROUTE */ 1123 .err = EACCES, 1124 .fatal = 1, 1125 }, 1126 }; 1127 1128 int icmpv6_err_convert(u8 type, u8 code, int *err) 1129 { 1130 int fatal = 0; 1131 1132 *err = EPROTO; 1133 1134 switch (type) { 1135 case ICMPV6_DEST_UNREACH: 1136 fatal = 1; 1137 if (code < ARRAY_SIZE(tab_unreach)) { 1138 *err = tab_unreach[code].err; 1139 fatal = tab_unreach[code].fatal; 1140 } 1141 break; 1142 1143 case ICMPV6_PKT_TOOBIG: 1144 *err = EMSGSIZE; 1145 break; 1146 1147 case ICMPV6_PARAMPROB: 1148 *err = EPROTO; 1149 fatal = 1; 1150 break; 1151 1152 case ICMPV6_TIME_EXCEED: 1153 *err = EHOSTUNREACH; 1154 break; 1155 } 1156 1157 return fatal; 1158 } 1159 EXPORT_SYMBOL(icmpv6_err_convert); 1160 1161 #ifdef CONFIG_SYSCTL 1162 static struct ctl_table ipv6_icmp_table_template[] = { 1163 { 1164 .procname = "ratelimit", 1165 .data = &init_net.ipv6.sysctl.icmpv6_time, 1166 .maxlen = sizeof(int), 1167 .mode = 0644, 1168 .proc_handler = proc_dointvec_ms_jiffies, 1169 }, 1170 { 1171 .procname = "echo_ignore_all", 1172 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_all, 1173 .maxlen = sizeof(u8), 1174 .mode = 0644, 1175 .proc_handler = proc_dou8vec_minmax, 1176 }, 1177 { 1178 .procname = "echo_ignore_multicast", 1179 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast, 1180 .maxlen = sizeof(u8), 1181 .mode = 0644, 1182 .proc_handler = proc_dou8vec_minmax, 1183 }, 1184 { 1185 .procname = "echo_ignore_anycast", 1186 .data = &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast, 1187 .maxlen = sizeof(u8), 1188 .mode = 0644, 1189 .proc_handler = proc_dou8vec_minmax, 1190 }, 1191 { 1192 .procname = "ratemask", 1193 .data = &init_net.ipv6.sysctl.icmpv6_ratemask_ptr, 1194 .maxlen = ICMPV6_MSG_MAX + 1, 1195 .mode = 0644, 1196 .proc_handler = proc_do_large_bitmap, 1197 }, 1198 { }, 1199 }; 1200 1201 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net) 1202 { 1203 struct ctl_table *table; 1204 1205 table = kmemdup(ipv6_icmp_table_template, 1206 sizeof(ipv6_icmp_table_template), 1207 GFP_KERNEL); 1208 1209 if (table) { 1210 table[0].data = &net->ipv6.sysctl.icmpv6_time; 1211 table[1].data = &net->ipv6.sysctl.icmpv6_echo_ignore_all; 1212 table[2].data = &net->ipv6.sysctl.icmpv6_echo_ignore_multicast; 1213 table[3].data = &net->ipv6.sysctl.icmpv6_echo_ignore_anycast; 1214 table[4].data = &net->ipv6.sysctl.icmpv6_ratemask_ptr; 1215 } 1216 return table; 1217 } 1218 #endif 1219