1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Extension Header handling for IPv6 4 * Linux INET6 implementation 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * Andi Kleen <ak@muc.de> 9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 10 */ 11 12 /* Changes: 13 * yoshfuji : ensure not to overrun while parsing 14 * tlv options. 15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). 16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header 17 * handlers as inet6_protocol{}. 18 */ 19 20 #include <linux/errno.h> 21 #include <linux/types.h> 22 #include <linux/socket.h> 23 #include <linux/sockios.h> 24 #include <linux/net.h> 25 #include <linux/netdevice.h> 26 #include <linux/in6.h> 27 #include <linux/icmpv6.h> 28 #include <linux/slab.h> 29 #include <linux/export.h> 30 31 #include <net/dst.h> 32 #include <net/sock.h> 33 #include <net/snmp.h> 34 35 #include <net/ipv6.h> 36 #include <net/protocol.h> 37 #include <net/transp_v6.h> 38 #include <net/rawv6.h> 39 #include <net/ndisc.h> 40 #include <net/ip6_route.h> 41 #include <net/addrconf.h> 42 #include <net/calipso.h> 43 #if IS_ENABLED(CONFIG_IPV6_MIP6) 44 #include <net/xfrm.h> 45 #endif 46 #include <linux/seg6.h> 47 #include <net/seg6.h> 48 #ifdef CONFIG_IPV6_SEG6_HMAC 49 #include <net/seg6_hmac.h> 50 #endif 51 52 #include <linux/uaccess.h> 53 54 /* 55 * Parsing tlv encoded headers. 56 * 57 * Parsing function "func" returns true, if parsing succeed 58 * and false, if it failed. 59 * It MUST NOT touch skb->h. 60 */ 61 62 struct tlvtype_proc { 63 int type; 64 bool (*func)(struct sk_buff *skb, int offset); 65 }; 66 67 /********************* 68 Generic functions 69 *********************/ 70 71 /* An unknown option is detected, decide what to do */ 72 73 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff, 74 bool disallow_unknowns) 75 { 76 if (disallow_unknowns) { 77 /* If unknown TLVs are disallowed by configuration 78 * then always silently drop packet. Note this also 79 * means no ICMP parameter problem is sent which 80 * could be a good property to mitigate a reflection DOS 81 * attack. 82 */ 83 84 goto drop; 85 } 86 87 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 88 case 0: /* ignore */ 89 return true; 90 91 case 1: /* drop packet */ 92 break; 93 94 case 3: /* Send ICMP if not a multicast address and drop packet */ 95 /* Actually, it is redundant check. icmp_send 96 will recheck in any case. 97 */ 98 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 99 break; 100 /* fall through */ 101 case 2: /* send ICMP PARM PROB regardless and drop packet */ 102 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 103 return false; 104 } 105 106 drop: 107 kfree_skb(skb); 108 return false; 109 } 110 111 /* Parse tlv encoded option header (hop-by-hop or destination) */ 112 113 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, 114 struct sk_buff *skb, 115 int max_count) 116 { 117 int len = (skb_transport_header(skb)[1] + 1) << 3; 118 const unsigned char *nh = skb_network_header(skb); 119 int off = skb_network_header_len(skb); 120 const struct tlvtype_proc *curr; 121 bool disallow_unknowns = false; 122 int tlv_count = 0; 123 int padlen = 0; 124 125 if (unlikely(max_count < 0)) { 126 disallow_unknowns = true; 127 max_count = -max_count; 128 } 129 130 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 131 goto bad; 132 133 off += 2; 134 len -= 2; 135 136 while (len > 0) { 137 int optlen = nh[off + 1] + 2; 138 int i; 139 140 switch (nh[off]) { 141 case IPV6_TLV_PAD1: 142 optlen = 1; 143 padlen++; 144 if (padlen > 7) 145 goto bad; 146 break; 147 148 case IPV6_TLV_PADN: 149 /* RFC 2460 states that the purpose of PadN is 150 * to align the containing header to multiples 151 * of 8. 7 is therefore the highest valid value. 152 * See also RFC 4942, Section 2.1.9.5. 153 */ 154 padlen += optlen; 155 if (padlen > 7) 156 goto bad; 157 /* RFC 4942 recommends receiving hosts to 158 * actively check PadN payload to contain 159 * only zeroes. 160 */ 161 for (i = 2; i < optlen; i++) { 162 if (nh[off + i] != 0) 163 goto bad; 164 } 165 break; 166 167 default: /* Other TLV code so scan list */ 168 if (optlen > len) 169 goto bad; 170 171 tlv_count++; 172 if (tlv_count > max_count) 173 goto bad; 174 175 for (curr = procs; curr->type >= 0; curr++) { 176 if (curr->type == nh[off]) { 177 /* type specific length/alignment 178 checks will be performed in the 179 func(). */ 180 if (curr->func(skb, off) == false) 181 return false; 182 break; 183 } 184 } 185 if (curr->type < 0 && 186 !ip6_tlvopt_unknown(skb, off, disallow_unknowns)) 187 return false; 188 189 padlen = 0; 190 break; 191 } 192 off += optlen; 193 len -= optlen; 194 } 195 196 if (len == 0) 197 return true; 198 bad: 199 kfree_skb(skb); 200 return false; 201 } 202 203 /***************************** 204 Destination options header. 205 *****************************/ 206 207 #if IS_ENABLED(CONFIG_IPV6_MIP6) 208 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 209 { 210 struct ipv6_destopt_hao *hao; 211 struct inet6_skb_parm *opt = IP6CB(skb); 212 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 213 int ret; 214 215 if (opt->dsthao) { 216 net_dbg_ratelimited("hao duplicated\n"); 217 goto discard; 218 } 219 opt->dsthao = opt->dst1; 220 opt->dst1 = 0; 221 222 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 223 224 if (hao->length != 16) { 225 net_dbg_ratelimited("hao invalid option length = %d\n", 226 hao->length); 227 goto discard; 228 } 229 230 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 231 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 232 &hao->addr); 233 goto discard; 234 } 235 236 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 237 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 238 if (unlikely(ret < 0)) 239 goto discard; 240 241 if (skb_cloned(skb)) { 242 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 243 goto discard; 244 245 /* update all variable using below by copied skbuff */ 246 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 247 optoff); 248 ipv6h = ipv6_hdr(skb); 249 } 250 251 if (skb->ip_summed == CHECKSUM_COMPLETE) 252 skb->ip_summed = CHECKSUM_NONE; 253 254 swap(ipv6h->saddr, hao->addr); 255 256 if (skb->tstamp == 0) 257 __net_timestamp(skb); 258 259 return true; 260 261 discard: 262 kfree_skb(skb); 263 return false; 264 } 265 #endif 266 267 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 268 #if IS_ENABLED(CONFIG_IPV6_MIP6) 269 { 270 .type = IPV6_TLV_HAO, 271 .func = ipv6_dest_hao, 272 }, 273 #endif 274 {-1, NULL} 275 }; 276 277 static int ipv6_destopt_rcv(struct sk_buff *skb) 278 { 279 struct inet6_dev *idev = __in6_dev_get(skb->dev); 280 struct inet6_skb_parm *opt = IP6CB(skb); 281 #if IS_ENABLED(CONFIG_IPV6_MIP6) 282 __u16 dstbuf; 283 #endif 284 struct dst_entry *dst = skb_dst(skb); 285 struct net *net = dev_net(skb->dev); 286 int extlen; 287 288 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 289 !pskb_may_pull(skb, (skb_transport_offset(skb) + 290 ((skb_transport_header(skb)[1] + 1) << 3)))) { 291 __IP6_INC_STATS(dev_net(dst->dev), idev, 292 IPSTATS_MIB_INHDRERRORS); 293 fail_and_free: 294 kfree_skb(skb); 295 return -1; 296 } 297 298 extlen = (skb_transport_header(skb)[1] + 1) << 3; 299 if (extlen > net->ipv6.sysctl.max_dst_opts_len) 300 goto fail_and_free; 301 302 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 303 #if IS_ENABLED(CONFIG_IPV6_MIP6) 304 dstbuf = opt->dst1; 305 #endif 306 307 if (ip6_parse_tlv(tlvprocdestopt_lst, skb, 308 init_net.ipv6.sysctl.max_dst_opts_cnt)) { 309 skb->transport_header += extlen; 310 opt = IP6CB(skb); 311 #if IS_ENABLED(CONFIG_IPV6_MIP6) 312 opt->nhoff = dstbuf; 313 #else 314 opt->nhoff = opt->dst1; 315 #endif 316 return 1; 317 } 318 319 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 320 return -1; 321 } 322 323 static void seg6_update_csum(struct sk_buff *skb) 324 { 325 struct ipv6_sr_hdr *hdr; 326 struct in6_addr *addr; 327 __be32 from, to; 328 329 /* srh is at transport offset and seg_left is already decremented 330 * but daddr is not yet updated with next segment 331 */ 332 333 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 334 addr = hdr->segments + hdr->segments_left; 335 336 hdr->segments_left++; 337 from = *(__be32 *)hdr; 338 339 hdr->segments_left--; 340 to = *(__be32 *)hdr; 341 342 /* update skb csum with diff resulting from seg_left decrement */ 343 344 update_csum_diff4(skb, from, to); 345 346 /* compute csum diff between current and next segment and update */ 347 348 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 349 (__be32 *)addr); 350 } 351 352 static int ipv6_srh_rcv(struct sk_buff *skb) 353 { 354 struct inet6_skb_parm *opt = IP6CB(skb); 355 struct net *net = dev_net(skb->dev); 356 struct ipv6_sr_hdr *hdr; 357 struct inet6_dev *idev; 358 struct in6_addr *addr; 359 int accept_seg6; 360 361 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 362 363 idev = __in6_dev_get(skb->dev); 364 365 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 366 if (accept_seg6 > idev->cnf.seg6_enabled) 367 accept_seg6 = idev->cnf.seg6_enabled; 368 369 if (!accept_seg6) { 370 kfree_skb(skb); 371 return -1; 372 } 373 374 #ifdef CONFIG_IPV6_SEG6_HMAC 375 if (!seg6_hmac_validate_skb(skb)) { 376 kfree_skb(skb); 377 return -1; 378 } 379 #endif 380 381 looped_back: 382 if (hdr->segments_left == 0) { 383 if (hdr->nexthdr == NEXTHDR_IPV6) { 384 int offset = (hdr->hdrlen + 1) << 3; 385 386 skb_postpull_rcsum(skb, skb_network_header(skb), 387 skb_network_header_len(skb)); 388 389 if (!pskb_pull(skb, offset)) { 390 kfree_skb(skb); 391 return -1; 392 } 393 skb_postpull_rcsum(skb, skb_transport_header(skb), 394 offset); 395 396 skb_reset_network_header(skb); 397 skb_reset_transport_header(skb); 398 skb->encapsulation = 0; 399 400 __skb_tunnel_rx(skb, skb->dev, net); 401 402 netif_rx(skb); 403 return -1; 404 } 405 406 opt->srcrt = skb_network_header_len(skb); 407 opt->lastopt = opt->srcrt; 408 skb->transport_header += (hdr->hdrlen + 1) << 3; 409 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 410 411 return 1; 412 } 413 414 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 415 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 416 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 417 ((&hdr->segments_left) - 418 skb_network_header(skb))); 419 return -1; 420 } 421 422 if (skb_cloned(skb)) { 423 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 424 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 425 IPSTATS_MIB_OUTDISCARDS); 426 kfree_skb(skb); 427 return -1; 428 } 429 } 430 431 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 432 433 hdr->segments_left--; 434 addr = hdr->segments + hdr->segments_left; 435 436 skb_push(skb, sizeof(struct ipv6hdr)); 437 438 if (skb->ip_summed == CHECKSUM_COMPLETE) 439 seg6_update_csum(skb); 440 441 ipv6_hdr(skb)->daddr = *addr; 442 443 skb_dst_drop(skb); 444 445 ip6_route_input(skb); 446 447 if (skb_dst(skb)->error) { 448 dst_input(skb); 449 return -1; 450 } 451 452 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 453 if (ipv6_hdr(skb)->hop_limit <= 1) { 454 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 455 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 456 ICMPV6_EXC_HOPLIMIT, 0); 457 kfree_skb(skb); 458 return -1; 459 } 460 ipv6_hdr(skb)->hop_limit--; 461 462 skb_pull(skb, sizeof(struct ipv6hdr)); 463 goto looped_back; 464 } 465 466 dst_input(skb); 467 468 return -1; 469 } 470 471 /******************************** 472 Routing header. 473 ********************************/ 474 475 /* called with rcu_read_lock() */ 476 static int ipv6_rthdr_rcv(struct sk_buff *skb) 477 { 478 struct inet6_dev *idev = __in6_dev_get(skb->dev); 479 struct inet6_skb_parm *opt = IP6CB(skb); 480 struct in6_addr *addr = NULL; 481 struct in6_addr daddr; 482 int n, i; 483 struct ipv6_rt_hdr *hdr; 484 struct rt0_hdr *rthdr; 485 struct net *net = dev_net(skb->dev); 486 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 487 488 idev = __in6_dev_get(skb->dev); 489 if (idev && accept_source_route > idev->cnf.accept_source_route) 490 accept_source_route = idev->cnf.accept_source_route; 491 492 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 493 !pskb_may_pull(skb, (skb_transport_offset(skb) + 494 ((skb_transport_header(skb)[1] + 1) << 3)))) { 495 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 496 kfree_skb(skb); 497 return -1; 498 } 499 500 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 501 502 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 503 skb->pkt_type != PACKET_HOST) { 504 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 505 kfree_skb(skb); 506 return -1; 507 } 508 509 /* segment routing */ 510 if (hdr->type == IPV6_SRCRT_TYPE_4) 511 return ipv6_srh_rcv(skb); 512 513 looped_back: 514 if (hdr->segments_left == 0) { 515 switch (hdr->type) { 516 #if IS_ENABLED(CONFIG_IPV6_MIP6) 517 case IPV6_SRCRT_TYPE_2: 518 /* Silently discard type 2 header unless it was 519 * processed by own 520 */ 521 if (!addr) { 522 __IP6_INC_STATS(net, idev, 523 IPSTATS_MIB_INADDRERRORS); 524 kfree_skb(skb); 525 return -1; 526 } 527 break; 528 #endif 529 default: 530 break; 531 } 532 533 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 534 skb->transport_header += (hdr->hdrlen + 1) << 3; 535 opt->dst0 = opt->dst1; 536 opt->dst1 = 0; 537 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 538 return 1; 539 } 540 541 switch (hdr->type) { 542 #if IS_ENABLED(CONFIG_IPV6_MIP6) 543 case IPV6_SRCRT_TYPE_2: 544 if (accept_source_route < 0) 545 goto unknown_rh; 546 /* Silently discard invalid RTH type 2 */ 547 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 548 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 549 kfree_skb(skb); 550 return -1; 551 } 552 break; 553 #endif 554 default: 555 goto unknown_rh; 556 } 557 558 /* 559 * This is the routing header forwarding algorithm from 560 * RFC 2460, page 16. 561 */ 562 563 n = hdr->hdrlen >> 1; 564 565 if (hdr->segments_left > n) { 566 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 567 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 568 ((&hdr->segments_left) - 569 skb_network_header(skb))); 570 return -1; 571 } 572 573 /* We are about to mangle packet header. Be careful! 574 Do not damage packets queued somewhere. 575 */ 576 if (skb_cloned(skb)) { 577 /* the copy is a forwarded packet */ 578 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 579 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 580 IPSTATS_MIB_OUTDISCARDS); 581 kfree_skb(skb); 582 return -1; 583 } 584 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 585 } 586 587 if (skb->ip_summed == CHECKSUM_COMPLETE) 588 skb->ip_summed = CHECKSUM_NONE; 589 590 i = n - --hdr->segments_left; 591 592 rthdr = (struct rt0_hdr *) hdr; 593 addr = rthdr->addr; 594 addr += i - 1; 595 596 switch (hdr->type) { 597 #if IS_ENABLED(CONFIG_IPV6_MIP6) 598 case IPV6_SRCRT_TYPE_2: 599 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 600 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 601 IPPROTO_ROUTING) < 0) { 602 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 603 kfree_skb(skb); 604 return -1; 605 } 606 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 607 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 608 kfree_skb(skb); 609 return -1; 610 } 611 break; 612 #endif 613 default: 614 break; 615 } 616 617 if (ipv6_addr_is_multicast(addr)) { 618 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 619 kfree_skb(skb); 620 return -1; 621 } 622 623 daddr = *addr; 624 *addr = ipv6_hdr(skb)->daddr; 625 ipv6_hdr(skb)->daddr = daddr; 626 627 skb_dst_drop(skb); 628 ip6_route_input(skb); 629 if (skb_dst(skb)->error) { 630 skb_push(skb, skb->data - skb_network_header(skb)); 631 dst_input(skb); 632 return -1; 633 } 634 635 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 636 if (ipv6_hdr(skb)->hop_limit <= 1) { 637 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 638 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 639 0); 640 kfree_skb(skb); 641 return -1; 642 } 643 ipv6_hdr(skb)->hop_limit--; 644 goto looped_back; 645 } 646 647 skb_push(skb, skb->data - skb_network_header(skb)); 648 dst_input(skb); 649 return -1; 650 651 unknown_rh: 652 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 653 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 654 (&hdr->type) - skb_network_header(skb)); 655 return -1; 656 } 657 658 static const struct inet6_protocol rthdr_protocol = { 659 .handler = ipv6_rthdr_rcv, 660 .flags = INET6_PROTO_NOPOLICY, 661 }; 662 663 static const struct inet6_protocol destopt_protocol = { 664 .handler = ipv6_destopt_rcv, 665 .flags = INET6_PROTO_NOPOLICY, 666 }; 667 668 static const struct inet6_protocol nodata_protocol = { 669 .handler = dst_discard, 670 .flags = INET6_PROTO_NOPOLICY, 671 }; 672 673 int __init ipv6_exthdrs_init(void) 674 { 675 int ret; 676 677 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 678 if (ret) 679 goto out; 680 681 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 682 if (ret) 683 goto out_rthdr; 684 685 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 686 if (ret) 687 goto out_destopt; 688 689 out: 690 return ret; 691 out_destopt: 692 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 693 out_rthdr: 694 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 695 goto out; 696 }; 697 698 void ipv6_exthdrs_exit(void) 699 { 700 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 701 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 702 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 703 } 704 705 /********************************** 706 Hop-by-hop options. 707 **********************************/ 708 709 /* 710 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 711 */ 712 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 713 { 714 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 715 } 716 717 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 718 { 719 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 720 } 721 722 /* Router Alert as of RFC 2711 */ 723 724 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 725 { 726 const unsigned char *nh = skb_network_header(skb); 727 728 if (nh[optoff + 1] == 2) { 729 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 730 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 731 return true; 732 } 733 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 734 nh[optoff + 1]); 735 kfree_skb(skb); 736 return false; 737 } 738 739 /* Jumbo payload */ 740 741 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 742 { 743 const unsigned char *nh = skb_network_header(skb); 744 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev); 745 struct net *net = ipv6_skb_net(skb); 746 u32 pkt_len; 747 748 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 749 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 750 nh[optoff+1]); 751 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 752 goto drop; 753 } 754 755 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 756 if (pkt_len <= IPV6_MAXPLEN) { 757 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 758 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 759 return false; 760 } 761 if (ipv6_hdr(skb)->payload_len) { 762 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 763 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 764 return false; 765 } 766 767 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 768 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS); 769 goto drop; 770 } 771 772 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 773 goto drop; 774 775 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 776 return true; 777 778 drop: 779 kfree_skb(skb); 780 return false; 781 } 782 783 /* CALIPSO RFC 5570 */ 784 785 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 786 { 787 const unsigned char *nh = skb_network_header(skb); 788 789 if (nh[optoff + 1] < 8) 790 goto drop; 791 792 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 793 goto drop; 794 795 if (!calipso_validate(skb, nh + optoff)) 796 goto drop; 797 798 return true; 799 800 drop: 801 kfree_skb(skb); 802 return false; 803 } 804 805 static const struct tlvtype_proc tlvprochopopt_lst[] = { 806 { 807 .type = IPV6_TLV_ROUTERALERT, 808 .func = ipv6_hop_ra, 809 }, 810 { 811 .type = IPV6_TLV_JUMBO, 812 .func = ipv6_hop_jumbo, 813 }, 814 { 815 .type = IPV6_TLV_CALIPSO, 816 .func = ipv6_hop_calipso, 817 }, 818 { -1, } 819 }; 820 821 int ipv6_parse_hopopts(struct sk_buff *skb) 822 { 823 struct inet6_skb_parm *opt = IP6CB(skb); 824 struct net *net = dev_net(skb->dev); 825 int extlen; 826 827 /* 828 * skb_network_header(skb) is equal to skb->data, and 829 * skb_network_header_len(skb) is always equal to 830 * sizeof(struct ipv6hdr) by definition of 831 * hop-by-hop options. 832 */ 833 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 834 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 835 ((skb_transport_header(skb)[1] + 1) << 3)))) { 836 fail_and_free: 837 kfree_skb(skb); 838 return -1; 839 } 840 841 extlen = (skb_transport_header(skb)[1] + 1) << 3; 842 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 843 goto fail_and_free; 844 845 opt->flags |= IP6SKB_HOPBYHOP; 846 if (ip6_parse_tlv(tlvprochopopt_lst, skb, 847 init_net.ipv6.sysctl.max_hbh_opts_cnt)) { 848 skb->transport_header += extlen; 849 opt = IP6CB(skb); 850 opt->nhoff = sizeof(struct ipv6hdr); 851 return 1; 852 } 853 return -1; 854 } 855 856 /* 857 * Creating outbound headers. 858 * 859 * "build" functions work when skb is filled from head to tail (datagram) 860 * "push" functions work when headers are added from tail to head (tcp) 861 * 862 * In both cases we assume, that caller reserved enough room 863 * for headers. 864 */ 865 866 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 867 struct ipv6_rt_hdr *opt, 868 struct in6_addr **addr_p, struct in6_addr *saddr) 869 { 870 struct rt0_hdr *phdr, *ihdr; 871 int hops; 872 873 ihdr = (struct rt0_hdr *) opt; 874 875 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 876 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 877 878 hops = ihdr->rt_hdr.hdrlen >> 1; 879 880 if (hops > 1) 881 memcpy(phdr->addr, ihdr->addr + 1, 882 (hops - 1) * sizeof(struct in6_addr)); 883 884 phdr->addr[hops - 1] = **addr_p; 885 *addr_p = ihdr->addr; 886 887 phdr->rt_hdr.nexthdr = *proto; 888 *proto = NEXTHDR_ROUTING; 889 } 890 891 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 892 struct ipv6_rt_hdr *opt, 893 struct in6_addr **addr_p, struct in6_addr *saddr) 894 { 895 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 896 int plen, hops; 897 898 sr_ihdr = (struct ipv6_sr_hdr *)opt; 899 plen = (sr_ihdr->hdrlen + 1) << 3; 900 901 sr_phdr = skb_push(skb, plen); 902 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 903 904 hops = sr_ihdr->first_segment + 1; 905 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 906 (hops - 1) * sizeof(struct in6_addr)); 907 908 sr_phdr->segments[0] = **addr_p; 909 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 910 911 if (sr_ihdr->hdrlen > hops * 2) { 912 int tlvs_offset, tlvs_length; 913 914 tlvs_offset = (1 + hops * 2) << 3; 915 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 916 memcpy((char *)sr_phdr + tlvs_offset, 917 (char *)sr_ihdr + tlvs_offset, tlvs_length); 918 } 919 920 #ifdef CONFIG_IPV6_SEG6_HMAC 921 if (sr_has_hmac(sr_phdr)) { 922 struct net *net = NULL; 923 924 if (skb->dev) 925 net = dev_net(skb->dev); 926 else if (skb->sk) 927 net = sock_net(skb->sk); 928 929 WARN_ON(!net); 930 931 if (net) 932 seg6_push_hmac(net, saddr, sr_phdr); 933 } 934 #endif 935 936 sr_phdr->nexthdr = *proto; 937 *proto = NEXTHDR_ROUTING; 938 } 939 940 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 941 struct ipv6_rt_hdr *opt, 942 struct in6_addr **addr_p, struct in6_addr *saddr) 943 { 944 switch (opt->type) { 945 case IPV6_SRCRT_TYPE_0: 946 case IPV6_SRCRT_STRICT: 947 case IPV6_SRCRT_TYPE_2: 948 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 949 break; 950 case IPV6_SRCRT_TYPE_4: 951 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 952 break; 953 default: 954 break; 955 } 956 } 957 958 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 959 { 960 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 961 962 memcpy(h, opt, ipv6_optlen(opt)); 963 h->nexthdr = *proto; 964 *proto = type; 965 } 966 967 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 968 u8 *proto, 969 struct in6_addr **daddr, struct in6_addr *saddr) 970 { 971 if (opt->srcrt) { 972 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 973 /* 974 * IPV6_RTHDRDSTOPTS is ignored 975 * unless IPV6_RTHDR is set (RFC3542). 976 */ 977 if (opt->dst0opt) 978 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 979 } 980 if (opt->hopopt) 981 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 982 } 983 984 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 985 { 986 if (opt->dst1opt) 987 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 988 } 989 EXPORT_SYMBOL(ipv6_push_frag_opts); 990 991 struct ipv6_txoptions * 992 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 993 { 994 struct ipv6_txoptions *opt2; 995 996 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 997 if (opt2) { 998 long dif = (char *)opt2 - (char *)opt; 999 memcpy(opt2, opt, opt->tot_len); 1000 if (opt2->hopopt) 1001 *((char **)&opt2->hopopt) += dif; 1002 if (opt2->dst0opt) 1003 *((char **)&opt2->dst0opt) += dif; 1004 if (opt2->dst1opt) 1005 *((char **)&opt2->dst1opt) += dif; 1006 if (opt2->srcrt) 1007 *((char **)&opt2->srcrt) += dif; 1008 refcount_set(&opt2->refcnt, 1); 1009 } 1010 return opt2; 1011 } 1012 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1013 1014 static void ipv6_renew_option(int renewtype, 1015 struct ipv6_opt_hdr **dest, 1016 struct ipv6_opt_hdr *old, 1017 struct ipv6_opt_hdr *new, 1018 int newtype, char **p) 1019 { 1020 struct ipv6_opt_hdr *src; 1021 1022 src = (renewtype == newtype ? new : old); 1023 if (!src) 1024 return; 1025 1026 memcpy(*p, src, ipv6_optlen(src)); 1027 *dest = (struct ipv6_opt_hdr *)*p; 1028 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1029 } 1030 1031 /** 1032 * ipv6_renew_options - replace a specific ext hdr with a new one. 1033 * 1034 * @sk: sock from which to allocate memory 1035 * @opt: original options 1036 * @newtype: option type to replace in @opt 1037 * @newopt: new option of type @newtype to replace (user-mem) 1038 * @newoptlen: length of @newopt 1039 * 1040 * Returns a new set of options which is a copy of @opt with the 1041 * option type @newtype replaced with @newopt. 1042 * 1043 * @opt may be NULL, in which case a new set of options is returned 1044 * containing just @newopt. 1045 * 1046 * @newopt may be NULL, in which case the specified option type is 1047 * not copied into the new set of options. 1048 * 1049 * The new set of options is allocated from the socket option memory 1050 * buffer of @sk. 1051 */ 1052 struct ipv6_txoptions * 1053 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1054 int newtype, struct ipv6_opt_hdr *newopt) 1055 { 1056 int tot_len = 0; 1057 char *p; 1058 struct ipv6_txoptions *opt2; 1059 1060 if (opt) { 1061 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1062 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1063 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1064 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1065 if (newtype != IPV6_RTHDR && opt->srcrt) 1066 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1067 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1068 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1069 } 1070 1071 if (newopt) 1072 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1073 1074 if (!tot_len) 1075 return NULL; 1076 1077 tot_len += sizeof(*opt2); 1078 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1079 if (!opt2) 1080 return ERR_PTR(-ENOBUFS); 1081 1082 memset(opt2, 0, tot_len); 1083 refcount_set(&opt2->refcnt, 1); 1084 opt2->tot_len = tot_len; 1085 p = (char *)(opt2 + 1); 1086 1087 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1088 (opt ? opt->hopopt : NULL), 1089 newopt, newtype, &p); 1090 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1091 (opt ? opt->dst0opt : NULL), 1092 newopt, newtype, &p); 1093 ipv6_renew_option(IPV6_RTHDR, 1094 (struct ipv6_opt_hdr **)&opt2->srcrt, 1095 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1096 newopt, newtype, &p); 1097 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1098 (opt ? opt->dst1opt : NULL), 1099 newopt, newtype, &p); 1100 1101 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1102 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1103 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1104 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1105 1106 return opt2; 1107 } 1108 1109 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1110 struct ipv6_txoptions *opt) 1111 { 1112 /* 1113 * ignore the dest before srcrt unless srcrt is being included. 1114 * --yoshfuji 1115 */ 1116 if (opt && opt->dst0opt && !opt->srcrt) { 1117 if (opt_space != opt) { 1118 memcpy(opt_space, opt, sizeof(*opt_space)); 1119 opt = opt_space; 1120 } 1121 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1122 opt->dst0opt = NULL; 1123 } 1124 1125 return opt; 1126 } 1127 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1128 1129 /** 1130 * fl6_update_dst - update flowi destination address with info given 1131 * by srcrt option, if any. 1132 * 1133 * @fl6: flowi6 for which daddr is to be updated 1134 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1135 * @orig: copy of original daddr address if modified 1136 * 1137 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1138 * and initial value of fl6->daddr set in orig 1139 */ 1140 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1141 const struct ipv6_txoptions *opt, 1142 struct in6_addr *orig) 1143 { 1144 if (!opt || !opt->srcrt) 1145 return NULL; 1146 1147 *orig = fl6->daddr; 1148 1149 switch (opt->srcrt->type) { 1150 case IPV6_SRCRT_TYPE_0: 1151 case IPV6_SRCRT_STRICT: 1152 case IPV6_SRCRT_TYPE_2: 1153 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1154 break; 1155 case IPV6_SRCRT_TYPE_4: 1156 { 1157 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1158 1159 fl6->daddr = srh->segments[srh->segments_left]; 1160 break; 1161 } 1162 default: 1163 return NULL; 1164 } 1165 1166 return orig; 1167 } 1168 EXPORT_SYMBOL_GPL(fl6_update_dst); 1169