1 /* 2 * Extension Header handling for IPv6 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * Andi Kleen <ak@muc.de> 8 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 /* Changes: 17 * yoshfuji : ensure not to overrun while parsing 18 * tlv options. 19 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). 20 * YOSHIFUJI Hideaki @USAGI Register inbound extension header 21 * handlers as inet6_protocol{}. 22 */ 23 24 #include <linux/errno.h> 25 #include <linux/types.h> 26 #include <linux/socket.h> 27 #include <linux/sockios.h> 28 #include <linux/net.h> 29 #include <linux/netdevice.h> 30 #include <linux/in6.h> 31 #include <linux/icmpv6.h> 32 #include <linux/slab.h> 33 #include <linux/export.h> 34 35 #include <net/dst.h> 36 #include <net/sock.h> 37 #include <net/snmp.h> 38 39 #include <net/ipv6.h> 40 #include <net/protocol.h> 41 #include <net/transp_v6.h> 42 #include <net/rawv6.h> 43 #include <net/ndisc.h> 44 #include <net/ip6_route.h> 45 #include <net/addrconf.h> 46 #include <net/calipso.h> 47 #if IS_ENABLED(CONFIG_IPV6_MIP6) 48 #include <net/xfrm.h> 49 #endif 50 #include <linux/seg6.h> 51 #include <net/seg6.h> 52 #ifdef CONFIG_IPV6_SEG6_HMAC 53 #include <net/seg6_hmac.h> 54 #endif 55 56 #include <linux/uaccess.h> 57 58 /* 59 * Parsing tlv encoded headers. 60 * 61 * Parsing function "func" returns true, if parsing succeed 62 * and false, if it failed. 63 * It MUST NOT touch skb->h. 64 */ 65 66 struct tlvtype_proc { 67 int type; 68 bool (*func)(struct sk_buff *skb, int offset); 69 }; 70 71 /********************* 72 Generic functions 73 *********************/ 74 75 /* An unknown option is detected, decide what to do */ 76 77 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff) 78 { 79 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 80 case 0: /* ignore */ 81 return true; 82 83 case 1: /* drop packet */ 84 break; 85 86 case 3: /* Send ICMP if not a multicast address and drop packet */ 87 /* Actually, it is redundant check. icmp_send 88 will recheck in any case. 89 */ 90 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 91 break; 92 case 2: /* send ICMP PARM PROB regardless and drop packet */ 93 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 94 return false; 95 } 96 97 kfree_skb(skb); 98 return false; 99 } 100 101 /* Parse tlv encoded option header (hop-by-hop or destination) */ 102 103 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb) 104 { 105 const struct tlvtype_proc *curr; 106 const unsigned char *nh = skb_network_header(skb); 107 int off = skb_network_header_len(skb); 108 int len = (skb_transport_header(skb)[1] + 1) << 3; 109 int padlen = 0; 110 111 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 112 goto bad; 113 114 off += 2; 115 len -= 2; 116 117 while (len > 0) { 118 int optlen = nh[off + 1] + 2; 119 int i; 120 121 switch (nh[off]) { 122 case IPV6_TLV_PAD1: 123 optlen = 1; 124 padlen++; 125 if (padlen > 7) 126 goto bad; 127 break; 128 129 case IPV6_TLV_PADN: 130 /* RFC 2460 states that the purpose of PadN is 131 * to align the containing header to multiples 132 * of 8. 7 is therefore the highest valid value. 133 * See also RFC 4942, Section 2.1.9.5. 134 */ 135 padlen += optlen; 136 if (padlen > 7) 137 goto bad; 138 /* RFC 4942 recommends receiving hosts to 139 * actively check PadN payload to contain 140 * only zeroes. 141 */ 142 for (i = 2; i < optlen; i++) { 143 if (nh[off + i] != 0) 144 goto bad; 145 } 146 break; 147 148 default: /* Other TLV code so scan list */ 149 if (optlen > len) 150 goto bad; 151 for (curr = procs; curr->type >= 0; curr++) { 152 if (curr->type == nh[off]) { 153 /* type specific length/alignment 154 checks will be performed in the 155 func(). */ 156 if (curr->func(skb, off) == false) 157 return false; 158 break; 159 } 160 } 161 if (curr->type < 0) { 162 if (ip6_tlvopt_unknown(skb, off) == 0) 163 return false; 164 } 165 padlen = 0; 166 break; 167 } 168 off += optlen; 169 len -= optlen; 170 } 171 172 if (len == 0) 173 return true; 174 bad: 175 kfree_skb(skb); 176 return false; 177 } 178 179 /***************************** 180 Destination options header. 181 *****************************/ 182 183 #if IS_ENABLED(CONFIG_IPV6_MIP6) 184 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 185 { 186 struct ipv6_destopt_hao *hao; 187 struct inet6_skb_parm *opt = IP6CB(skb); 188 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 189 struct in6_addr tmp_addr; 190 int ret; 191 192 if (opt->dsthao) { 193 net_dbg_ratelimited("hao duplicated\n"); 194 goto discard; 195 } 196 opt->dsthao = opt->dst1; 197 opt->dst1 = 0; 198 199 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 200 201 if (hao->length != 16) { 202 net_dbg_ratelimited("hao invalid option length = %d\n", 203 hao->length); 204 goto discard; 205 } 206 207 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 208 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 209 &hao->addr); 210 goto discard; 211 } 212 213 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 214 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 215 if (unlikely(ret < 0)) 216 goto discard; 217 218 if (skb_cloned(skb)) { 219 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 220 goto discard; 221 222 /* update all variable using below by copied skbuff */ 223 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 224 optoff); 225 ipv6h = ipv6_hdr(skb); 226 } 227 228 if (skb->ip_summed == CHECKSUM_COMPLETE) 229 skb->ip_summed = CHECKSUM_NONE; 230 231 tmp_addr = ipv6h->saddr; 232 ipv6h->saddr = hao->addr; 233 hao->addr = tmp_addr; 234 235 if (skb->tstamp == 0) 236 __net_timestamp(skb); 237 238 return true; 239 240 discard: 241 kfree_skb(skb); 242 return false; 243 } 244 #endif 245 246 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 247 #if IS_ENABLED(CONFIG_IPV6_MIP6) 248 { 249 .type = IPV6_TLV_HAO, 250 .func = ipv6_dest_hao, 251 }, 252 #endif 253 {-1, NULL} 254 }; 255 256 static int ipv6_destopt_rcv(struct sk_buff *skb) 257 { 258 struct inet6_skb_parm *opt = IP6CB(skb); 259 #if IS_ENABLED(CONFIG_IPV6_MIP6) 260 __u16 dstbuf; 261 #endif 262 struct dst_entry *dst = skb_dst(skb); 263 264 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 265 !pskb_may_pull(skb, (skb_transport_offset(skb) + 266 ((skb_transport_header(skb)[1] + 1) << 3)))) { 267 __IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst), 268 IPSTATS_MIB_INHDRERRORS); 269 kfree_skb(skb); 270 return -1; 271 } 272 273 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 274 #if IS_ENABLED(CONFIG_IPV6_MIP6) 275 dstbuf = opt->dst1; 276 #endif 277 278 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) { 279 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 280 opt = IP6CB(skb); 281 #if IS_ENABLED(CONFIG_IPV6_MIP6) 282 opt->nhoff = dstbuf; 283 #else 284 opt->nhoff = opt->dst1; 285 #endif 286 return 1; 287 } 288 289 __IP6_INC_STATS(dev_net(dst->dev), 290 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); 291 return -1; 292 } 293 294 static void seg6_update_csum(struct sk_buff *skb) 295 { 296 struct ipv6_sr_hdr *hdr; 297 struct in6_addr *addr; 298 __be32 from, to; 299 300 /* srh is at transport offset and seg_left is already decremented 301 * but daddr is not yet updated with next segment 302 */ 303 304 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 305 addr = hdr->segments + hdr->segments_left; 306 307 hdr->segments_left++; 308 from = *(__be32 *)hdr; 309 310 hdr->segments_left--; 311 to = *(__be32 *)hdr; 312 313 /* update skb csum with diff resulting from seg_left decrement */ 314 315 update_csum_diff4(skb, from, to); 316 317 /* compute csum diff between current and next segment and update */ 318 319 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 320 (__be32 *)addr); 321 } 322 323 static int ipv6_srh_rcv(struct sk_buff *skb) 324 { 325 struct inet6_skb_parm *opt = IP6CB(skb); 326 struct net *net = dev_net(skb->dev); 327 struct ipv6_sr_hdr *hdr; 328 struct inet6_dev *idev; 329 struct in6_addr *addr; 330 bool cleanup = false; 331 int accept_seg6; 332 333 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 334 335 idev = __in6_dev_get(skb->dev); 336 337 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 338 if (accept_seg6 > idev->cnf.seg6_enabled) 339 accept_seg6 = idev->cnf.seg6_enabled; 340 341 if (!accept_seg6) { 342 kfree_skb(skb); 343 return -1; 344 } 345 346 #ifdef CONFIG_IPV6_SEG6_HMAC 347 if (!seg6_hmac_validate_skb(skb)) { 348 kfree_skb(skb); 349 return -1; 350 } 351 #endif 352 353 looped_back: 354 if (hdr->segments_left > 0) { 355 if (hdr->nexthdr != NEXTHDR_IPV6 && hdr->segments_left == 1 && 356 sr_has_cleanup(hdr)) 357 cleanup = true; 358 } else { 359 if (hdr->nexthdr == NEXTHDR_IPV6) { 360 int offset = (hdr->hdrlen + 1) << 3; 361 362 skb_postpull_rcsum(skb, skb_network_header(skb), 363 skb_network_header_len(skb)); 364 365 if (!pskb_pull(skb, offset)) { 366 kfree_skb(skb); 367 return -1; 368 } 369 skb_postpull_rcsum(skb, skb_transport_header(skb), 370 offset); 371 372 skb_reset_network_header(skb); 373 skb_reset_transport_header(skb); 374 skb->encapsulation = 0; 375 376 __skb_tunnel_rx(skb, skb->dev, net); 377 378 netif_rx(skb); 379 return -1; 380 } 381 382 opt->srcrt = skb_network_header_len(skb); 383 opt->lastopt = opt->srcrt; 384 skb->transport_header += (hdr->hdrlen + 1) << 3; 385 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 386 387 return 1; 388 } 389 390 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 391 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 392 IPSTATS_MIB_INHDRERRORS); 393 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 394 ((&hdr->segments_left) - 395 skb_network_header(skb))); 396 kfree_skb(skb); 397 return -1; 398 } 399 400 if (skb_cloned(skb)) { 401 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 402 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 403 IPSTATS_MIB_OUTDISCARDS); 404 kfree_skb(skb); 405 return -1; 406 } 407 } 408 409 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 410 411 hdr->segments_left--; 412 addr = hdr->segments + hdr->segments_left; 413 414 skb_push(skb, sizeof(struct ipv6hdr)); 415 416 if (skb->ip_summed == CHECKSUM_COMPLETE) 417 seg6_update_csum(skb); 418 419 ipv6_hdr(skb)->daddr = *addr; 420 421 if (cleanup) { 422 int srhlen = (hdr->hdrlen + 1) << 3; 423 int nh = hdr->nexthdr; 424 425 skb_pull_rcsum(skb, sizeof(struct ipv6hdr) + srhlen); 426 memmove(skb_network_header(skb) + srhlen, 427 skb_network_header(skb), 428 (unsigned char *)hdr - skb_network_header(skb)); 429 skb->network_header += srhlen; 430 ipv6_hdr(skb)->nexthdr = nh; 431 ipv6_hdr(skb)->payload_len = htons(skb->len - 432 sizeof(struct ipv6hdr)); 433 skb_push_rcsum(skb, sizeof(struct ipv6hdr)); 434 } 435 436 skb_dst_drop(skb); 437 438 ip6_route_input(skb); 439 440 if (skb_dst(skb)->error) { 441 dst_input(skb); 442 return -1; 443 } 444 445 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 446 if (ipv6_hdr(skb)->hop_limit <= 1) { 447 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 448 IPSTATS_MIB_INHDRERRORS); 449 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 450 ICMPV6_EXC_HOPLIMIT, 0); 451 kfree_skb(skb); 452 return -1; 453 } 454 ipv6_hdr(skb)->hop_limit--; 455 456 /* be sure that srh is still present before reinjecting */ 457 if (!cleanup) { 458 skb_pull(skb, sizeof(struct ipv6hdr)); 459 goto looped_back; 460 } 461 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 462 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr); 463 } 464 465 dst_input(skb); 466 467 return -1; 468 } 469 470 /******************************** 471 Routing header. 472 ********************************/ 473 474 /* called with rcu_read_lock() */ 475 static int ipv6_rthdr_rcv(struct sk_buff *skb) 476 { 477 struct inet6_skb_parm *opt = IP6CB(skb); 478 struct in6_addr *addr = NULL; 479 struct in6_addr daddr; 480 struct inet6_dev *idev; 481 int n, i; 482 struct ipv6_rt_hdr *hdr; 483 struct rt0_hdr *rthdr; 484 struct net *net = dev_net(skb->dev); 485 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 486 487 idev = __in6_dev_get(skb->dev); 488 if (idev && accept_source_route > idev->cnf.accept_source_route) 489 accept_source_route = idev->cnf.accept_source_route; 490 491 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 492 !pskb_may_pull(skb, (skb_transport_offset(skb) + 493 ((skb_transport_header(skb)[1] + 1) << 3)))) { 494 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 495 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, ip6_dst_idev(skb_dst(skb)), 505 IPSTATS_MIB_INADDRERRORS); 506 kfree_skb(skb); 507 return -1; 508 } 509 510 /* segment routing */ 511 if (hdr->type == IPV6_SRCRT_TYPE_4) 512 return ipv6_srh_rcv(skb); 513 514 looped_back: 515 if (hdr->segments_left == 0) { 516 switch (hdr->type) { 517 #if IS_ENABLED(CONFIG_IPV6_MIP6) 518 case IPV6_SRCRT_TYPE_2: 519 /* Silently discard type 2 header unless it was 520 * processed by own 521 */ 522 if (!addr) { 523 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 524 IPSTATS_MIB_INADDRERRORS); 525 kfree_skb(skb); 526 return -1; 527 } 528 break; 529 #endif 530 default: 531 break; 532 } 533 534 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 535 skb->transport_header += (hdr->hdrlen + 1) << 3; 536 opt->dst0 = opt->dst1; 537 opt->dst1 = 0; 538 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 539 return 1; 540 } 541 542 switch (hdr->type) { 543 #if IS_ENABLED(CONFIG_IPV6_MIP6) 544 case IPV6_SRCRT_TYPE_2: 545 if (accept_source_route < 0) 546 goto unknown_rh; 547 /* Silently discard invalid RTH type 2 */ 548 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 549 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 550 IPSTATS_MIB_INHDRERRORS); 551 kfree_skb(skb); 552 return -1; 553 } 554 break; 555 #endif 556 default: 557 goto unknown_rh; 558 } 559 560 /* 561 * This is the routing header forwarding algorithm from 562 * RFC 2460, page 16. 563 */ 564 565 n = hdr->hdrlen >> 1; 566 567 if (hdr->segments_left > n) { 568 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 569 IPSTATS_MIB_INHDRERRORS); 570 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 571 ((&hdr->segments_left) - 572 skb_network_header(skb))); 573 return -1; 574 } 575 576 /* We are about to mangle packet header. Be careful! 577 Do not damage packets queued somewhere. 578 */ 579 if (skb_cloned(skb)) { 580 /* the copy is a forwarded packet */ 581 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 582 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 583 IPSTATS_MIB_OUTDISCARDS); 584 kfree_skb(skb); 585 return -1; 586 } 587 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 588 } 589 590 if (skb->ip_summed == CHECKSUM_COMPLETE) 591 skb->ip_summed = CHECKSUM_NONE; 592 593 i = n - --hdr->segments_left; 594 595 rthdr = (struct rt0_hdr *) hdr; 596 addr = rthdr->addr; 597 addr += i - 1; 598 599 switch (hdr->type) { 600 #if IS_ENABLED(CONFIG_IPV6_MIP6) 601 case IPV6_SRCRT_TYPE_2: 602 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 603 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 604 IPPROTO_ROUTING) < 0) { 605 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 606 IPSTATS_MIB_INADDRERRORS); 607 kfree_skb(skb); 608 return -1; 609 } 610 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 611 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 612 IPSTATS_MIB_INADDRERRORS); 613 kfree_skb(skb); 614 return -1; 615 } 616 break; 617 #endif 618 default: 619 break; 620 } 621 622 if (ipv6_addr_is_multicast(addr)) { 623 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 624 IPSTATS_MIB_INADDRERRORS); 625 kfree_skb(skb); 626 return -1; 627 } 628 629 daddr = *addr; 630 *addr = ipv6_hdr(skb)->daddr; 631 ipv6_hdr(skb)->daddr = daddr; 632 633 skb_dst_drop(skb); 634 ip6_route_input(skb); 635 if (skb_dst(skb)->error) { 636 skb_push(skb, skb->data - skb_network_header(skb)); 637 dst_input(skb); 638 return -1; 639 } 640 641 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 642 if (ipv6_hdr(skb)->hop_limit <= 1) { 643 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 644 IPSTATS_MIB_INHDRERRORS); 645 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 646 0); 647 kfree_skb(skb); 648 return -1; 649 } 650 ipv6_hdr(skb)->hop_limit--; 651 goto looped_back; 652 } 653 654 skb_push(skb, skb->data - skb_network_header(skb)); 655 dst_input(skb); 656 return -1; 657 658 unknown_rh: 659 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); 660 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 661 (&hdr->type) - skb_network_header(skb)); 662 return -1; 663 } 664 665 static const struct inet6_protocol rthdr_protocol = { 666 .handler = ipv6_rthdr_rcv, 667 .flags = INET6_PROTO_NOPOLICY, 668 }; 669 670 static const struct inet6_protocol destopt_protocol = { 671 .handler = ipv6_destopt_rcv, 672 .flags = INET6_PROTO_NOPOLICY, 673 }; 674 675 static const struct inet6_protocol nodata_protocol = { 676 .handler = dst_discard, 677 .flags = INET6_PROTO_NOPOLICY, 678 }; 679 680 int __init ipv6_exthdrs_init(void) 681 { 682 int ret; 683 684 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 685 if (ret) 686 goto out; 687 688 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 689 if (ret) 690 goto out_rthdr; 691 692 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 693 if (ret) 694 goto out_destopt; 695 696 out: 697 return ret; 698 out_destopt: 699 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 700 out_rthdr: 701 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 702 goto out; 703 }; 704 705 void ipv6_exthdrs_exit(void) 706 { 707 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 708 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 709 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 710 } 711 712 /********************************** 713 Hop-by-hop options. 714 **********************************/ 715 716 /* 717 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 718 */ 719 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 720 { 721 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 722 } 723 724 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 725 { 726 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 727 } 728 729 /* Router Alert as of RFC 2711 */ 730 731 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 732 { 733 const unsigned char *nh = skb_network_header(skb); 734 735 if (nh[optoff + 1] == 2) { 736 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 737 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 738 return true; 739 } 740 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 741 nh[optoff + 1]); 742 kfree_skb(skb); 743 return false; 744 } 745 746 /* Jumbo payload */ 747 748 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 749 { 750 const unsigned char *nh = skb_network_header(skb); 751 struct net *net = ipv6_skb_net(skb); 752 u32 pkt_len; 753 754 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 755 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 756 nh[optoff+1]); 757 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 758 IPSTATS_MIB_INHDRERRORS); 759 goto drop; 760 } 761 762 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 763 if (pkt_len <= IPV6_MAXPLEN) { 764 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 765 IPSTATS_MIB_INHDRERRORS); 766 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 767 return false; 768 } 769 if (ipv6_hdr(skb)->payload_len) { 770 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 771 IPSTATS_MIB_INHDRERRORS); 772 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 773 return false; 774 } 775 776 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 777 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 778 IPSTATS_MIB_INTRUNCATEDPKTS); 779 goto drop; 780 } 781 782 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 783 goto drop; 784 785 return true; 786 787 drop: 788 kfree_skb(skb); 789 return false; 790 } 791 792 /* CALIPSO RFC 5570 */ 793 794 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 795 { 796 const unsigned char *nh = skb_network_header(skb); 797 798 if (nh[optoff + 1] < 8) 799 goto drop; 800 801 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 802 goto drop; 803 804 if (!calipso_validate(skb, nh + optoff)) 805 goto drop; 806 807 return true; 808 809 drop: 810 kfree_skb(skb); 811 return false; 812 } 813 814 static const struct tlvtype_proc tlvprochopopt_lst[] = { 815 { 816 .type = IPV6_TLV_ROUTERALERT, 817 .func = ipv6_hop_ra, 818 }, 819 { 820 .type = IPV6_TLV_JUMBO, 821 .func = ipv6_hop_jumbo, 822 }, 823 { 824 .type = IPV6_TLV_CALIPSO, 825 .func = ipv6_hop_calipso, 826 }, 827 { -1, } 828 }; 829 830 int ipv6_parse_hopopts(struct sk_buff *skb) 831 { 832 struct inet6_skb_parm *opt = IP6CB(skb); 833 834 /* 835 * skb_network_header(skb) is equal to skb->data, and 836 * skb_network_header_len(skb) is always equal to 837 * sizeof(struct ipv6hdr) by definition of 838 * hop-by-hop options. 839 */ 840 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 841 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 842 ((skb_transport_header(skb)[1] + 1) << 3)))) { 843 kfree_skb(skb); 844 return -1; 845 } 846 847 opt->flags |= IP6SKB_HOPBYHOP; 848 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) { 849 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 850 opt = IP6CB(skb); 851 opt->nhoff = sizeof(struct ipv6hdr); 852 return 1; 853 } 854 return -1; 855 } 856 857 /* 858 * Creating outbound headers. 859 * 860 * "build" functions work when skb is filled from head to tail (datagram) 861 * "push" functions work when headers are added from tail to head (tcp) 862 * 863 * In both cases we assume, that caller reserved enough room 864 * for headers. 865 */ 866 867 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 868 struct ipv6_rt_hdr *opt, 869 struct in6_addr **addr_p, struct in6_addr *saddr) 870 { 871 struct rt0_hdr *phdr, *ihdr; 872 int hops; 873 874 ihdr = (struct rt0_hdr *) opt; 875 876 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 877 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 878 879 hops = ihdr->rt_hdr.hdrlen >> 1; 880 881 if (hops > 1) 882 memcpy(phdr->addr, ihdr->addr + 1, 883 (hops - 1) * sizeof(struct in6_addr)); 884 885 phdr->addr[hops - 1] = **addr_p; 886 *addr_p = ihdr->addr; 887 888 phdr->rt_hdr.nexthdr = *proto; 889 *proto = NEXTHDR_ROUTING; 890 } 891 892 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 893 struct ipv6_rt_hdr *opt, 894 struct in6_addr **addr_p, struct in6_addr *saddr) 895 { 896 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 897 int plen, hops; 898 899 sr_ihdr = (struct ipv6_sr_hdr *)opt; 900 plen = (sr_ihdr->hdrlen + 1) << 3; 901 902 sr_phdr = (struct ipv6_sr_hdr *)skb_push(skb, plen); 903 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 904 905 hops = sr_ihdr->first_segment + 1; 906 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 907 (hops - 1) * sizeof(struct in6_addr)); 908 909 sr_phdr->segments[0] = **addr_p; 910 *addr_p = &sr_ihdr->segments[hops - 1]; 911 912 #ifdef CONFIG_IPV6_SEG6_HMAC 913 if (sr_has_hmac(sr_phdr)) { 914 struct net *net = NULL; 915 916 if (skb->dev) 917 net = dev_net(skb->dev); 918 else if (skb->sk) 919 net = sock_net(skb->sk); 920 921 WARN_ON(!net); 922 923 if (net) 924 seg6_push_hmac(net, saddr, sr_phdr); 925 } 926 #endif 927 928 sr_phdr->nexthdr = *proto; 929 *proto = NEXTHDR_ROUTING; 930 } 931 932 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 933 struct ipv6_rt_hdr *opt, 934 struct in6_addr **addr_p, struct in6_addr *saddr) 935 { 936 switch (opt->type) { 937 case IPV6_SRCRT_TYPE_0: 938 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 939 break; 940 case IPV6_SRCRT_TYPE_4: 941 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 942 break; 943 default: 944 break; 945 } 946 } 947 948 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 949 { 950 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt)); 951 952 memcpy(h, opt, ipv6_optlen(opt)); 953 h->nexthdr = *proto; 954 *proto = type; 955 } 956 957 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 958 u8 *proto, 959 struct in6_addr **daddr, struct in6_addr *saddr) 960 { 961 if (opt->srcrt) { 962 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 963 /* 964 * IPV6_RTHDRDSTOPTS is ignored 965 * unless IPV6_RTHDR is set (RFC3542). 966 */ 967 if (opt->dst0opt) 968 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 969 } 970 if (opt->hopopt) 971 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 972 } 973 EXPORT_SYMBOL(ipv6_push_nfrag_opts); 974 975 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 976 { 977 if (opt->dst1opt) 978 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 979 } 980 981 struct ipv6_txoptions * 982 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 983 { 984 struct ipv6_txoptions *opt2; 985 986 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 987 if (opt2) { 988 long dif = (char *)opt2 - (char *)opt; 989 memcpy(opt2, opt, opt->tot_len); 990 if (opt2->hopopt) 991 *((char **)&opt2->hopopt) += dif; 992 if (opt2->dst0opt) 993 *((char **)&opt2->dst0opt) += dif; 994 if (opt2->dst1opt) 995 *((char **)&opt2->dst1opt) += dif; 996 if (opt2->srcrt) 997 *((char **)&opt2->srcrt) += dif; 998 atomic_set(&opt2->refcnt, 1); 999 } 1000 return opt2; 1001 } 1002 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1003 1004 static int ipv6_renew_option(void *ohdr, 1005 struct ipv6_opt_hdr __user *newopt, int newoptlen, 1006 int inherit, 1007 struct ipv6_opt_hdr **hdr, 1008 char **p) 1009 { 1010 if (inherit) { 1011 if (ohdr) { 1012 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); 1013 *hdr = (struct ipv6_opt_hdr *)*p; 1014 *p += CMSG_ALIGN(ipv6_optlen(*hdr)); 1015 } 1016 } else { 1017 if (newopt) { 1018 if (copy_from_user(*p, newopt, newoptlen)) 1019 return -EFAULT; 1020 *hdr = (struct ipv6_opt_hdr *)*p; 1021 if (ipv6_optlen(*hdr) > newoptlen) 1022 return -EINVAL; 1023 *p += CMSG_ALIGN(newoptlen); 1024 } 1025 } 1026 return 0; 1027 } 1028 1029 /** 1030 * ipv6_renew_options - replace a specific ext hdr with a new one. 1031 * 1032 * @sk: sock from which to allocate memory 1033 * @opt: original options 1034 * @newtype: option type to replace in @opt 1035 * @newopt: new option of type @newtype to replace (user-mem) 1036 * @newoptlen: length of @newopt 1037 * 1038 * Returns a new set of options which is a copy of @opt with the 1039 * option type @newtype replaced with @newopt. 1040 * 1041 * @opt may be NULL, in which case a new set of options is returned 1042 * containing just @newopt. 1043 * 1044 * @newopt may be NULL, in which case the specified option type is 1045 * not copied into the new set of options. 1046 * 1047 * The new set of options is allocated from the socket option memory 1048 * buffer of @sk. 1049 */ 1050 struct ipv6_txoptions * 1051 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1052 int newtype, 1053 struct ipv6_opt_hdr __user *newopt, int newoptlen) 1054 { 1055 int tot_len = 0; 1056 char *p; 1057 struct ipv6_txoptions *opt2; 1058 int err; 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 && newoptlen) 1072 tot_len += CMSG_ALIGN(newoptlen); 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 atomic_set(&opt2->refcnt, 1); 1084 opt2->tot_len = tot_len; 1085 p = (char *)(opt2 + 1); 1086 1087 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, 1088 newtype != IPV6_HOPOPTS, 1089 &opt2->hopopt, &p); 1090 if (err) 1091 goto out; 1092 1093 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, 1094 newtype != IPV6_RTHDRDSTOPTS, 1095 &opt2->dst0opt, &p); 1096 if (err) 1097 goto out; 1098 1099 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, 1100 newtype != IPV6_RTHDR, 1101 (struct ipv6_opt_hdr **)&opt2->srcrt, &p); 1102 if (err) 1103 goto out; 1104 1105 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, 1106 newtype != IPV6_DSTOPTS, 1107 &opt2->dst1opt, &p); 1108 if (err) 1109 goto out; 1110 1111 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1112 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1113 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1114 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1115 1116 return opt2; 1117 out: 1118 sock_kfree_s(sk, opt2, opt2->tot_len); 1119 return ERR_PTR(err); 1120 } 1121 1122 /** 1123 * ipv6_renew_options_kern - replace a specific ext hdr with a new one. 1124 * 1125 * @sk: sock from which to allocate memory 1126 * @opt: original options 1127 * @newtype: option type to replace in @opt 1128 * @newopt: new option of type @newtype to replace (kernel-mem) 1129 * @newoptlen: length of @newopt 1130 * 1131 * See ipv6_renew_options(). The difference is that @newopt is 1132 * kernel memory, rather than user memory. 1133 */ 1134 struct ipv6_txoptions * 1135 ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt, 1136 int newtype, struct ipv6_opt_hdr *newopt, 1137 int newoptlen) 1138 { 1139 struct ipv6_txoptions *ret_val; 1140 const mm_segment_t old_fs = get_fs(); 1141 1142 set_fs(KERNEL_DS); 1143 ret_val = ipv6_renew_options(sk, opt, newtype, 1144 (struct ipv6_opt_hdr __user *)newopt, 1145 newoptlen); 1146 set_fs(old_fs); 1147 return ret_val; 1148 } 1149 1150 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1151 struct ipv6_txoptions *opt) 1152 { 1153 /* 1154 * ignore the dest before srcrt unless srcrt is being included. 1155 * --yoshfuji 1156 */ 1157 if (opt && opt->dst0opt && !opt->srcrt) { 1158 if (opt_space != opt) { 1159 memcpy(opt_space, opt, sizeof(*opt_space)); 1160 opt = opt_space; 1161 } 1162 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1163 opt->dst0opt = NULL; 1164 } 1165 1166 return opt; 1167 } 1168 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1169 1170 /** 1171 * fl6_update_dst - update flowi destination address with info given 1172 * by srcrt option, if any. 1173 * 1174 * @fl6: flowi6 for which daddr is to be updated 1175 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1176 * @orig: copy of original daddr address if modified 1177 * 1178 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1179 * and initial value of fl6->daddr set in orig 1180 */ 1181 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1182 const struct ipv6_txoptions *opt, 1183 struct in6_addr *orig) 1184 { 1185 if (!opt || !opt->srcrt) 1186 return NULL; 1187 1188 *orig = fl6->daddr; 1189 1190 switch (opt->srcrt->type) { 1191 case IPV6_SRCRT_TYPE_0: 1192 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1193 break; 1194 case IPV6_SRCRT_TYPE_4: 1195 { 1196 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1197 1198 fl6->daddr = srh->segments[srh->first_segment]; 1199 break; 1200 } 1201 default: 1202 return NULL; 1203 } 1204 1205 return orig; 1206 } 1207 EXPORT_SYMBOL_GPL(fl6_update_dst); 1208