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 /* fall through */ 93 case 2: /* send ICMP PARM PROB regardless and drop packet */ 94 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 95 return false; 96 } 97 98 kfree_skb(skb); 99 return false; 100 } 101 102 /* Parse tlv encoded option header (hop-by-hop or destination) */ 103 104 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb) 105 { 106 const struct tlvtype_proc *curr; 107 const unsigned char *nh = skb_network_header(skb); 108 int off = skb_network_header_len(skb); 109 int len = (skb_transport_header(skb)[1] + 1) << 3; 110 int padlen = 0; 111 112 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 113 goto bad; 114 115 off += 2; 116 len -= 2; 117 118 while (len > 0) { 119 int optlen = nh[off + 1] + 2; 120 int i; 121 122 switch (nh[off]) { 123 case IPV6_TLV_PAD1: 124 optlen = 1; 125 padlen++; 126 if (padlen > 7) 127 goto bad; 128 break; 129 130 case IPV6_TLV_PADN: 131 /* RFC 2460 states that the purpose of PadN is 132 * to align the containing header to multiples 133 * of 8. 7 is therefore the highest valid value. 134 * See also RFC 4942, Section 2.1.9.5. 135 */ 136 padlen += optlen; 137 if (padlen > 7) 138 goto bad; 139 /* RFC 4942 recommends receiving hosts to 140 * actively check PadN payload to contain 141 * only zeroes. 142 */ 143 for (i = 2; i < optlen; i++) { 144 if (nh[off + i] != 0) 145 goto bad; 146 } 147 break; 148 149 default: /* Other TLV code so scan list */ 150 if (optlen > len) 151 goto bad; 152 for (curr = procs; curr->type >= 0; curr++) { 153 if (curr->type == nh[off]) { 154 /* type specific length/alignment 155 checks will be performed in the 156 func(). */ 157 if (curr->func(skb, off) == false) 158 return false; 159 break; 160 } 161 } 162 if (curr->type < 0) { 163 if (ip6_tlvopt_unknown(skb, off) == 0) 164 return false; 165 } 166 padlen = 0; 167 break; 168 } 169 off += optlen; 170 len -= optlen; 171 } 172 173 if (len == 0) 174 return true; 175 bad: 176 kfree_skb(skb); 177 return false; 178 } 179 180 /***************************** 181 Destination options header. 182 *****************************/ 183 184 #if IS_ENABLED(CONFIG_IPV6_MIP6) 185 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 186 { 187 struct ipv6_destopt_hao *hao; 188 struct inet6_skb_parm *opt = IP6CB(skb); 189 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 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 swap(ipv6h->saddr, hao->addr); 232 233 if (skb->tstamp == 0) 234 __net_timestamp(skb); 235 236 return true; 237 238 discard: 239 kfree_skb(skb); 240 return false; 241 } 242 #endif 243 244 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 245 #if IS_ENABLED(CONFIG_IPV6_MIP6) 246 { 247 .type = IPV6_TLV_HAO, 248 .func = ipv6_dest_hao, 249 }, 250 #endif 251 {-1, NULL} 252 }; 253 254 static int ipv6_destopt_rcv(struct sk_buff *skb) 255 { 256 struct inet6_skb_parm *opt = IP6CB(skb); 257 #if IS_ENABLED(CONFIG_IPV6_MIP6) 258 __u16 dstbuf; 259 #endif 260 struct dst_entry *dst = skb_dst(skb); 261 262 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 263 !pskb_may_pull(skb, (skb_transport_offset(skb) + 264 ((skb_transport_header(skb)[1] + 1) << 3)))) { 265 __IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst), 266 IPSTATS_MIB_INHDRERRORS); 267 kfree_skb(skb); 268 return -1; 269 } 270 271 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 272 #if IS_ENABLED(CONFIG_IPV6_MIP6) 273 dstbuf = opt->dst1; 274 #endif 275 276 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) { 277 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 278 opt = IP6CB(skb); 279 #if IS_ENABLED(CONFIG_IPV6_MIP6) 280 opt->nhoff = dstbuf; 281 #else 282 opt->nhoff = opt->dst1; 283 #endif 284 return 1; 285 } 286 287 __IP6_INC_STATS(dev_net(dst->dev), 288 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); 289 return -1; 290 } 291 292 static void seg6_update_csum(struct sk_buff *skb) 293 { 294 struct ipv6_sr_hdr *hdr; 295 struct in6_addr *addr; 296 __be32 from, to; 297 298 /* srh is at transport offset and seg_left is already decremented 299 * but daddr is not yet updated with next segment 300 */ 301 302 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 303 addr = hdr->segments + hdr->segments_left; 304 305 hdr->segments_left++; 306 from = *(__be32 *)hdr; 307 308 hdr->segments_left--; 309 to = *(__be32 *)hdr; 310 311 /* update skb csum with diff resulting from seg_left decrement */ 312 313 update_csum_diff4(skb, from, to); 314 315 /* compute csum diff between current and next segment and update */ 316 317 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 318 (__be32 *)addr); 319 } 320 321 static int ipv6_srh_rcv(struct sk_buff *skb) 322 { 323 struct inet6_skb_parm *opt = IP6CB(skb); 324 struct net *net = dev_net(skb->dev); 325 struct ipv6_sr_hdr *hdr; 326 struct inet6_dev *idev; 327 struct in6_addr *addr; 328 int accept_seg6; 329 330 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 331 332 idev = __in6_dev_get(skb->dev); 333 334 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 335 if (accept_seg6 > idev->cnf.seg6_enabled) 336 accept_seg6 = idev->cnf.seg6_enabled; 337 338 if (!accept_seg6) { 339 kfree_skb(skb); 340 return -1; 341 } 342 343 #ifdef CONFIG_IPV6_SEG6_HMAC 344 if (!seg6_hmac_validate_skb(skb)) { 345 kfree_skb(skb); 346 return -1; 347 } 348 #endif 349 350 looped_back: 351 if (hdr->segments_left == 0) { 352 if (hdr->nexthdr == NEXTHDR_IPV6) { 353 int offset = (hdr->hdrlen + 1) << 3; 354 355 skb_postpull_rcsum(skb, skb_network_header(skb), 356 skb_network_header_len(skb)); 357 358 if (!pskb_pull(skb, offset)) { 359 kfree_skb(skb); 360 return -1; 361 } 362 skb_postpull_rcsum(skb, skb_transport_header(skb), 363 offset); 364 365 skb_reset_network_header(skb); 366 skb_reset_transport_header(skb); 367 skb->encapsulation = 0; 368 369 __skb_tunnel_rx(skb, skb->dev, net); 370 371 netif_rx(skb); 372 return -1; 373 } 374 375 opt->srcrt = skb_network_header_len(skb); 376 opt->lastopt = opt->srcrt; 377 skb->transport_header += (hdr->hdrlen + 1) << 3; 378 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 379 380 return 1; 381 } 382 383 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 384 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 385 IPSTATS_MIB_INHDRERRORS); 386 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 387 ((&hdr->segments_left) - 388 skb_network_header(skb))); 389 return -1; 390 } 391 392 if (skb_cloned(skb)) { 393 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 394 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 395 IPSTATS_MIB_OUTDISCARDS); 396 kfree_skb(skb); 397 return -1; 398 } 399 } 400 401 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 402 403 hdr->segments_left--; 404 addr = hdr->segments + hdr->segments_left; 405 406 skb_push(skb, sizeof(struct ipv6hdr)); 407 408 if (skb->ip_summed == CHECKSUM_COMPLETE) 409 seg6_update_csum(skb); 410 411 ipv6_hdr(skb)->daddr = *addr; 412 413 skb_dst_drop(skb); 414 415 ip6_route_input(skb); 416 417 if (skb_dst(skb)->error) { 418 dst_input(skb); 419 return -1; 420 } 421 422 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 423 if (ipv6_hdr(skb)->hop_limit <= 1) { 424 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 425 IPSTATS_MIB_INHDRERRORS); 426 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 427 ICMPV6_EXC_HOPLIMIT, 0); 428 kfree_skb(skb); 429 return -1; 430 } 431 ipv6_hdr(skb)->hop_limit--; 432 433 skb_pull(skb, sizeof(struct ipv6hdr)); 434 goto looped_back; 435 } 436 437 dst_input(skb); 438 439 return -1; 440 } 441 442 /******************************** 443 Routing header. 444 ********************************/ 445 446 /* called with rcu_read_lock() */ 447 static int ipv6_rthdr_rcv(struct sk_buff *skb) 448 { 449 struct inet6_skb_parm *opt = IP6CB(skb); 450 struct in6_addr *addr = NULL; 451 struct in6_addr daddr; 452 struct inet6_dev *idev; 453 int n, i; 454 struct ipv6_rt_hdr *hdr; 455 struct rt0_hdr *rthdr; 456 struct net *net = dev_net(skb->dev); 457 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 458 459 idev = __in6_dev_get(skb->dev); 460 if (idev && accept_source_route > idev->cnf.accept_source_route) 461 accept_source_route = idev->cnf.accept_source_route; 462 463 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 464 !pskb_may_pull(skb, (skb_transport_offset(skb) + 465 ((skb_transport_header(skb)[1] + 1) << 3)))) { 466 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 467 IPSTATS_MIB_INHDRERRORS); 468 kfree_skb(skb); 469 return -1; 470 } 471 472 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 473 474 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 475 skb->pkt_type != PACKET_HOST) { 476 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 477 IPSTATS_MIB_INADDRERRORS); 478 kfree_skb(skb); 479 return -1; 480 } 481 482 /* segment routing */ 483 if (hdr->type == IPV6_SRCRT_TYPE_4) 484 return ipv6_srh_rcv(skb); 485 486 looped_back: 487 if (hdr->segments_left == 0) { 488 switch (hdr->type) { 489 #if IS_ENABLED(CONFIG_IPV6_MIP6) 490 case IPV6_SRCRT_TYPE_2: 491 /* Silently discard type 2 header unless it was 492 * processed by own 493 */ 494 if (!addr) { 495 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 496 IPSTATS_MIB_INADDRERRORS); 497 kfree_skb(skb); 498 return -1; 499 } 500 break; 501 #endif 502 default: 503 break; 504 } 505 506 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 507 skb->transport_header += (hdr->hdrlen + 1) << 3; 508 opt->dst0 = opt->dst1; 509 opt->dst1 = 0; 510 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 511 return 1; 512 } 513 514 switch (hdr->type) { 515 #if IS_ENABLED(CONFIG_IPV6_MIP6) 516 case IPV6_SRCRT_TYPE_2: 517 if (accept_source_route < 0) 518 goto unknown_rh; 519 /* Silently discard invalid RTH type 2 */ 520 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 521 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 522 IPSTATS_MIB_INHDRERRORS); 523 kfree_skb(skb); 524 return -1; 525 } 526 break; 527 #endif 528 default: 529 goto unknown_rh; 530 } 531 532 /* 533 * This is the routing header forwarding algorithm from 534 * RFC 2460, page 16. 535 */ 536 537 n = hdr->hdrlen >> 1; 538 539 if (hdr->segments_left > n) { 540 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 541 IPSTATS_MIB_INHDRERRORS); 542 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 543 ((&hdr->segments_left) - 544 skb_network_header(skb))); 545 return -1; 546 } 547 548 /* We are about to mangle packet header. Be careful! 549 Do not damage packets queued somewhere. 550 */ 551 if (skb_cloned(skb)) { 552 /* the copy is a forwarded packet */ 553 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 554 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 555 IPSTATS_MIB_OUTDISCARDS); 556 kfree_skb(skb); 557 return -1; 558 } 559 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 560 } 561 562 if (skb->ip_summed == CHECKSUM_COMPLETE) 563 skb->ip_summed = CHECKSUM_NONE; 564 565 i = n - --hdr->segments_left; 566 567 rthdr = (struct rt0_hdr *) hdr; 568 addr = rthdr->addr; 569 addr += i - 1; 570 571 switch (hdr->type) { 572 #if IS_ENABLED(CONFIG_IPV6_MIP6) 573 case IPV6_SRCRT_TYPE_2: 574 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 575 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 576 IPPROTO_ROUTING) < 0) { 577 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 578 IPSTATS_MIB_INADDRERRORS); 579 kfree_skb(skb); 580 return -1; 581 } 582 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 583 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 584 IPSTATS_MIB_INADDRERRORS); 585 kfree_skb(skb); 586 return -1; 587 } 588 break; 589 #endif 590 default: 591 break; 592 } 593 594 if (ipv6_addr_is_multicast(addr)) { 595 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 596 IPSTATS_MIB_INADDRERRORS); 597 kfree_skb(skb); 598 return -1; 599 } 600 601 daddr = *addr; 602 *addr = ipv6_hdr(skb)->daddr; 603 ipv6_hdr(skb)->daddr = daddr; 604 605 skb_dst_drop(skb); 606 ip6_route_input(skb); 607 if (skb_dst(skb)->error) { 608 skb_push(skb, skb->data - skb_network_header(skb)); 609 dst_input(skb); 610 return -1; 611 } 612 613 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 614 if (ipv6_hdr(skb)->hop_limit <= 1) { 615 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 616 IPSTATS_MIB_INHDRERRORS); 617 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 618 0); 619 kfree_skb(skb); 620 return -1; 621 } 622 ipv6_hdr(skb)->hop_limit--; 623 goto looped_back; 624 } 625 626 skb_push(skb, skb->data - skb_network_header(skb)); 627 dst_input(skb); 628 return -1; 629 630 unknown_rh: 631 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); 632 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 633 (&hdr->type) - skb_network_header(skb)); 634 return -1; 635 } 636 637 static const struct inet6_protocol rthdr_protocol = { 638 .handler = ipv6_rthdr_rcv, 639 .flags = INET6_PROTO_NOPOLICY, 640 }; 641 642 static const struct inet6_protocol destopt_protocol = { 643 .handler = ipv6_destopt_rcv, 644 .flags = INET6_PROTO_NOPOLICY, 645 }; 646 647 static const struct inet6_protocol nodata_protocol = { 648 .handler = dst_discard, 649 .flags = INET6_PROTO_NOPOLICY, 650 }; 651 652 int __init ipv6_exthdrs_init(void) 653 { 654 int ret; 655 656 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 657 if (ret) 658 goto out; 659 660 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 661 if (ret) 662 goto out_rthdr; 663 664 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 665 if (ret) 666 goto out_destopt; 667 668 out: 669 return ret; 670 out_destopt: 671 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 672 out_rthdr: 673 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 674 goto out; 675 }; 676 677 void ipv6_exthdrs_exit(void) 678 { 679 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 680 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 681 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 682 } 683 684 /********************************** 685 Hop-by-hop options. 686 **********************************/ 687 688 /* 689 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 690 */ 691 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 692 { 693 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 694 } 695 696 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 697 { 698 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 699 } 700 701 /* Router Alert as of RFC 2711 */ 702 703 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 704 { 705 const unsigned char *nh = skb_network_header(skb); 706 707 if (nh[optoff + 1] == 2) { 708 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 709 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 710 return true; 711 } 712 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 713 nh[optoff + 1]); 714 kfree_skb(skb); 715 return false; 716 } 717 718 /* Jumbo payload */ 719 720 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 721 { 722 const unsigned char *nh = skb_network_header(skb); 723 struct net *net = ipv6_skb_net(skb); 724 u32 pkt_len; 725 726 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 727 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 728 nh[optoff+1]); 729 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 730 IPSTATS_MIB_INHDRERRORS); 731 goto drop; 732 } 733 734 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 735 if (pkt_len <= IPV6_MAXPLEN) { 736 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 737 IPSTATS_MIB_INHDRERRORS); 738 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 739 return false; 740 } 741 if (ipv6_hdr(skb)->payload_len) { 742 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 743 IPSTATS_MIB_INHDRERRORS); 744 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 745 return false; 746 } 747 748 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 749 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 750 IPSTATS_MIB_INTRUNCATEDPKTS); 751 goto drop; 752 } 753 754 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 755 goto drop; 756 757 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 758 return true; 759 760 drop: 761 kfree_skb(skb); 762 return false; 763 } 764 765 /* CALIPSO RFC 5570 */ 766 767 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 768 { 769 const unsigned char *nh = skb_network_header(skb); 770 771 if (nh[optoff + 1] < 8) 772 goto drop; 773 774 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 775 goto drop; 776 777 if (!calipso_validate(skb, nh + optoff)) 778 goto drop; 779 780 return true; 781 782 drop: 783 kfree_skb(skb); 784 return false; 785 } 786 787 static const struct tlvtype_proc tlvprochopopt_lst[] = { 788 { 789 .type = IPV6_TLV_ROUTERALERT, 790 .func = ipv6_hop_ra, 791 }, 792 { 793 .type = IPV6_TLV_JUMBO, 794 .func = ipv6_hop_jumbo, 795 }, 796 { 797 .type = IPV6_TLV_CALIPSO, 798 .func = ipv6_hop_calipso, 799 }, 800 { -1, } 801 }; 802 803 int ipv6_parse_hopopts(struct sk_buff *skb) 804 { 805 struct inet6_skb_parm *opt = IP6CB(skb); 806 807 /* 808 * skb_network_header(skb) is equal to skb->data, and 809 * skb_network_header_len(skb) is always equal to 810 * sizeof(struct ipv6hdr) by definition of 811 * hop-by-hop options. 812 */ 813 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 814 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 815 ((skb_transport_header(skb)[1] + 1) << 3)))) { 816 kfree_skb(skb); 817 return -1; 818 } 819 820 opt->flags |= IP6SKB_HOPBYHOP; 821 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) { 822 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 823 opt = IP6CB(skb); 824 opt->nhoff = sizeof(struct ipv6hdr); 825 return 1; 826 } 827 return -1; 828 } 829 830 /* 831 * Creating outbound headers. 832 * 833 * "build" functions work when skb is filled from head to tail (datagram) 834 * "push" functions work when headers are added from tail to head (tcp) 835 * 836 * In both cases we assume, that caller reserved enough room 837 * for headers. 838 */ 839 840 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 841 struct ipv6_rt_hdr *opt, 842 struct in6_addr **addr_p, struct in6_addr *saddr) 843 { 844 struct rt0_hdr *phdr, *ihdr; 845 int hops; 846 847 ihdr = (struct rt0_hdr *) opt; 848 849 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 850 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 851 852 hops = ihdr->rt_hdr.hdrlen >> 1; 853 854 if (hops > 1) 855 memcpy(phdr->addr, ihdr->addr + 1, 856 (hops - 1) * sizeof(struct in6_addr)); 857 858 phdr->addr[hops - 1] = **addr_p; 859 *addr_p = ihdr->addr; 860 861 phdr->rt_hdr.nexthdr = *proto; 862 *proto = NEXTHDR_ROUTING; 863 } 864 865 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 866 struct ipv6_rt_hdr *opt, 867 struct in6_addr **addr_p, struct in6_addr *saddr) 868 { 869 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 870 int plen, hops; 871 872 sr_ihdr = (struct ipv6_sr_hdr *)opt; 873 plen = (sr_ihdr->hdrlen + 1) << 3; 874 875 sr_phdr = skb_push(skb, plen); 876 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 877 878 hops = sr_ihdr->first_segment + 1; 879 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 880 (hops - 1) * sizeof(struct in6_addr)); 881 882 sr_phdr->segments[0] = **addr_p; 883 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 884 885 #ifdef CONFIG_IPV6_SEG6_HMAC 886 if (sr_has_hmac(sr_phdr)) { 887 struct net *net = NULL; 888 889 if (skb->dev) 890 net = dev_net(skb->dev); 891 else if (skb->sk) 892 net = sock_net(skb->sk); 893 894 WARN_ON(!net); 895 896 if (net) 897 seg6_push_hmac(net, saddr, sr_phdr); 898 } 899 #endif 900 901 sr_phdr->nexthdr = *proto; 902 *proto = NEXTHDR_ROUTING; 903 } 904 905 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 906 struct ipv6_rt_hdr *opt, 907 struct in6_addr **addr_p, struct in6_addr *saddr) 908 { 909 switch (opt->type) { 910 case IPV6_SRCRT_TYPE_0: 911 case IPV6_SRCRT_STRICT: 912 case IPV6_SRCRT_TYPE_2: 913 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 914 break; 915 case IPV6_SRCRT_TYPE_4: 916 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 917 break; 918 default: 919 break; 920 } 921 } 922 923 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 924 { 925 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 926 927 memcpy(h, opt, ipv6_optlen(opt)); 928 h->nexthdr = *proto; 929 *proto = type; 930 } 931 932 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 933 u8 *proto, 934 struct in6_addr **daddr, struct in6_addr *saddr) 935 { 936 if (opt->srcrt) { 937 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 938 /* 939 * IPV6_RTHDRDSTOPTS is ignored 940 * unless IPV6_RTHDR is set (RFC3542). 941 */ 942 if (opt->dst0opt) 943 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 944 } 945 if (opt->hopopt) 946 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 947 } 948 949 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 950 { 951 if (opt->dst1opt) 952 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 953 } 954 EXPORT_SYMBOL(ipv6_push_frag_opts); 955 956 struct ipv6_txoptions * 957 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 958 { 959 struct ipv6_txoptions *opt2; 960 961 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 962 if (opt2) { 963 long dif = (char *)opt2 - (char *)opt; 964 memcpy(opt2, opt, opt->tot_len); 965 if (opt2->hopopt) 966 *((char **)&opt2->hopopt) += dif; 967 if (opt2->dst0opt) 968 *((char **)&opt2->dst0opt) += dif; 969 if (opt2->dst1opt) 970 *((char **)&opt2->dst1opt) += dif; 971 if (opt2->srcrt) 972 *((char **)&opt2->srcrt) += dif; 973 refcount_set(&opt2->refcnt, 1); 974 } 975 return opt2; 976 } 977 EXPORT_SYMBOL_GPL(ipv6_dup_options); 978 979 static int ipv6_renew_option(void *ohdr, 980 struct ipv6_opt_hdr __user *newopt, int newoptlen, 981 int inherit, 982 struct ipv6_opt_hdr **hdr, 983 char **p) 984 { 985 if (inherit) { 986 if (ohdr) { 987 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); 988 *hdr = (struct ipv6_opt_hdr *)*p; 989 *p += CMSG_ALIGN(ipv6_optlen(*hdr)); 990 } 991 } else { 992 if (newopt) { 993 if (copy_from_user(*p, newopt, newoptlen)) 994 return -EFAULT; 995 *hdr = (struct ipv6_opt_hdr *)*p; 996 if (ipv6_optlen(*hdr) > newoptlen) 997 return -EINVAL; 998 *p += CMSG_ALIGN(newoptlen); 999 } 1000 } 1001 return 0; 1002 } 1003 1004 /** 1005 * ipv6_renew_options - replace a specific ext hdr with a new one. 1006 * 1007 * @sk: sock from which to allocate memory 1008 * @opt: original options 1009 * @newtype: option type to replace in @opt 1010 * @newopt: new option of type @newtype to replace (user-mem) 1011 * @newoptlen: length of @newopt 1012 * 1013 * Returns a new set of options which is a copy of @opt with the 1014 * option type @newtype replaced with @newopt. 1015 * 1016 * @opt may be NULL, in which case a new set of options is returned 1017 * containing just @newopt. 1018 * 1019 * @newopt may be NULL, in which case the specified option type is 1020 * not copied into the new set of options. 1021 * 1022 * The new set of options is allocated from the socket option memory 1023 * buffer of @sk. 1024 */ 1025 struct ipv6_txoptions * 1026 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1027 int newtype, 1028 struct ipv6_opt_hdr __user *newopt, int newoptlen) 1029 { 1030 int tot_len = 0; 1031 char *p; 1032 struct ipv6_txoptions *opt2; 1033 int err; 1034 1035 if (opt) { 1036 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1037 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1038 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1039 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1040 if (newtype != IPV6_RTHDR && opt->srcrt) 1041 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1042 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1043 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1044 } 1045 1046 if (newopt && newoptlen) 1047 tot_len += CMSG_ALIGN(newoptlen); 1048 1049 if (!tot_len) 1050 return NULL; 1051 1052 tot_len += sizeof(*opt2); 1053 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1054 if (!opt2) 1055 return ERR_PTR(-ENOBUFS); 1056 1057 memset(opt2, 0, tot_len); 1058 refcount_set(&opt2->refcnt, 1); 1059 opt2->tot_len = tot_len; 1060 p = (char *)(opt2 + 1); 1061 1062 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, 1063 newtype != IPV6_HOPOPTS, 1064 &opt2->hopopt, &p); 1065 if (err) 1066 goto out; 1067 1068 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, 1069 newtype != IPV6_RTHDRDSTOPTS, 1070 &opt2->dst0opt, &p); 1071 if (err) 1072 goto out; 1073 1074 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, 1075 newtype != IPV6_RTHDR, 1076 (struct ipv6_opt_hdr **)&opt2->srcrt, &p); 1077 if (err) 1078 goto out; 1079 1080 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, 1081 newtype != IPV6_DSTOPTS, 1082 &opt2->dst1opt, &p); 1083 if (err) 1084 goto out; 1085 1086 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1087 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1088 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1089 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1090 1091 return opt2; 1092 out: 1093 sock_kfree_s(sk, opt2, opt2->tot_len); 1094 return ERR_PTR(err); 1095 } 1096 1097 /** 1098 * ipv6_renew_options_kern - replace a specific ext hdr with a new one. 1099 * 1100 * @sk: sock from which to allocate memory 1101 * @opt: original options 1102 * @newtype: option type to replace in @opt 1103 * @newopt: new option of type @newtype to replace (kernel-mem) 1104 * @newoptlen: length of @newopt 1105 * 1106 * See ipv6_renew_options(). The difference is that @newopt is 1107 * kernel memory, rather than user memory. 1108 */ 1109 struct ipv6_txoptions * 1110 ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt, 1111 int newtype, struct ipv6_opt_hdr *newopt, 1112 int newoptlen) 1113 { 1114 struct ipv6_txoptions *ret_val; 1115 const mm_segment_t old_fs = get_fs(); 1116 1117 set_fs(KERNEL_DS); 1118 ret_val = ipv6_renew_options(sk, opt, newtype, 1119 (struct ipv6_opt_hdr __user *)newopt, 1120 newoptlen); 1121 set_fs(old_fs); 1122 return ret_val; 1123 } 1124 1125 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1126 struct ipv6_txoptions *opt) 1127 { 1128 /* 1129 * ignore the dest before srcrt unless srcrt is being included. 1130 * --yoshfuji 1131 */ 1132 if (opt && opt->dst0opt && !opt->srcrt) { 1133 if (opt_space != opt) { 1134 memcpy(opt_space, opt, sizeof(*opt_space)); 1135 opt = opt_space; 1136 } 1137 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1138 opt->dst0opt = NULL; 1139 } 1140 1141 return opt; 1142 } 1143 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1144 1145 /** 1146 * fl6_update_dst - update flowi destination address with info given 1147 * by srcrt option, if any. 1148 * 1149 * @fl6: flowi6 for which daddr is to be updated 1150 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1151 * @orig: copy of original daddr address if modified 1152 * 1153 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1154 * and initial value of fl6->daddr set in orig 1155 */ 1156 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1157 const struct ipv6_txoptions *opt, 1158 struct in6_addr *orig) 1159 { 1160 if (!opt || !opt->srcrt) 1161 return NULL; 1162 1163 *orig = fl6->daddr; 1164 1165 switch (opt->srcrt->type) { 1166 case IPV6_SRCRT_TYPE_0: 1167 case IPV6_SRCRT_STRICT: 1168 case IPV6_SRCRT_TYPE_2: 1169 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1170 break; 1171 case IPV6_SRCRT_TYPE_4: 1172 { 1173 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1174 1175 fl6->daddr = srh->segments[srh->segments_left]; 1176 break; 1177 } 1178 default: 1179 return NULL; 1180 } 1181 1182 return orig; 1183 } 1184 EXPORT_SYMBOL_GPL(fl6_update_dst); 1185