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 int accept_seg6; 331 332 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 333 334 idev = __in6_dev_get(skb->dev); 335 336 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 337 if (accept_seg6 > idev->cnf.seg6_enabled) 338 accept_seg6 = idev->cnf.seg6_enabled; 339 340 if (!accept_seg6) { 341 kfree_skb(skb); 342 return -1; 343 } 344 345 #ifdef CONFIG_IPV6_SEG6_HMAC 346 if (!seg6_hmac_validate_skb(skb)) { 347 kfree_skb(skb); 348 return -1; 349 } 350 #endif 351 352 looped_back: 353 if (hdr->segments_left == 0) { 354 if (hdr->nexthdr == NEXTHDR_IPV6) { 355 int offset = (hdr->hdrlen + 1) << 3; 356 357 skb_postpull_rcsum(skb, skb_network_header(skb), 358 skb_network_header_len(skb)); 359 360 if (!pskb_pull(skb, offset)) { 361 kfree_skb(skb); 362 return -1; 363 } 364 skb_postpull_rcsum(skb, skb_transport_header(skb), 365 offset); 366 367 skb_reset_network_header(skb); 368 skb_reset_transport_header(skb); 369 skb->encapsulation = 0; 370 371 __skb_tunnel_rx(skb, skb->dev, net); 372 373 netif_rx(skb); 374 return -1; 375 } 376 377 opt->srcrt = skb_network_header_len(skb); 378 opt->lastopt = opt->srcrt; 379 skb->transport_header += (hdr->hdrlen + 1) << 3; 380 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 381 382 return 1; 383 } 384 385 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 386 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 387 IPSTATS_MIB_INHDRERRORS); 388 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 389 ((&hdr->segments_left) - 390 skb_network_header(skb))); 391 return -1; 392 } 393 394 if (skb_cloned(skb)) { 395 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 396 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 397 IPSTATS_MIB_OUTDISCARDS); 398 kfree_skb(skb); 399 return -1; 400 } 401 } 402 403 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 404 405 hdr->segments_left--; 406 addr = hdr->segments + hdr->segments_left; 407 408 skb_push(skb, sizeof(struct ipv6hdr)); 409 410 if (skb->ip_summed == CHECKSUM_COMPLETE) 411 seg6_update_csum(skb); 412 413 ipv6_hdr(skb)->daddr = *addr; 414 415 skb_dst_drop(skb); 416 417 ip6_route_input(skb); 418 419 if (skb_dst(skb)->error) { 420 dst_input(skb); 421 return -1; 422 } 423 424 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 425 if (ipv6_hdr(skb)->hop_limit <= 1) { 426 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 427 IPSTATS_MIB_INHDRERRORS); 428 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 429 ICMPV6_EXC_HOPLIMIT, 0); 430 kfree_skb(skb); 431 return -1; 432 } 433 ipv6_hdr(skb)->hop_limit--; 434 435 skb_pull(skb, sizeof(struct ipv6hdr)); 436 goto looped_back; 437 } 438 439 dst_input(skb); 440 441 return -1; 442 } 443 444 /******************************** 445 Routing header. 446 ********************************/ 447 448 /* called with rcu_read_lock() */ 449 static int ipv6_rthdr_rcv(struct sk_buff *skb) 450 { 451 struct inet6_skb_parm *opt = IP6CB(skb); 452 struct in6_addr *addr = NULL; 453 struct in6_addr daddr; 454 struct inet6_dev *idev; 455 int n, i; 456 struct ipv6_rt_hdr *hdr; 457 struct rt0_hdr *rthdr; 458 struct net *net = dev_net(skb->dev); 459 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 460 461 idev = __in6_dev_get(skb->dev); 462 if (idev && accept_source_route > idev->cnf.accept_source_route) 463 accept_source_route = idev->cnf.accept_source_route; 464 465 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 466 !pskb_may_pull(skb, (skb_transport_offset(skb) + 467 ((skb_transport_header(skb)[1] + 1) << 3)))) { 468 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 469 IPSTATS_MIB_INHDRERRORS); 470 kfree_skb(skb); 471 return -1; 472 } 473 474 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 475 476 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 477 skb->pkt_type != PACKET_HOST) { 478 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 479 IPSTATS_MIB_INADDRERRORS); 480 kfree_skb(skb); 481 return -1; 482 } 483 484 /* segment routing */ 485 if (hdr->type == IPV6_SRCRT_TYPE_4) 486 return ipv6_srh_rcv(skb); 487 488 looped_back: 489 if (hdr->segments_left == 0) { 490 switch (hdr->type) { 491 #if IS_ENABLED(CONFIG_IPV6_MIP6) 492 case IPV6_SRCRT_TYPE_2: 493 /* Silently discard type 2 header unless it was 494 * processed by own 495 */ 496 if (!addr) { 497 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 498 IPSTATS_MIB_INADDRERRORS); 499 kfree_skb(skb); 500 return -1; 501 } 502 break; 503 #endif 504 default: 505 break; 506 } 507 508 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 509 skb->transport_header += (hdr->hdrlen + 1) << 3; 510 opt->dst0 = opt->dst1; 511 opt->dst1 = 0; 512 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 513 return 1; 514 } 515 516 switch (hdr->type) { 517 #if IS_ENABLED(CONFIG_IPV6_MIP6) 518 case IPV6_SRCRT_TYPE_2: 519 if (accept_source_route < 0) 520 goto unknown_rh; 521 /* Silently discard invalid RTH type 2 */ 522 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 523 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 524 IPSTATS_MIB_INHDRERRORS); 525 kfree_skb(skb); 526 return -1; 527 } 528 break; 529 #endif 530 default: 531 goto unknown_rh; 532 } 533 534 /* 535 * This is the routing header forwarding algorithm from 536 * RFC 2460, page 16. 537 */ 538 539 n = hdr->hdrlen >> 1; 540 541 if (hdr->segments_left > n) { 542 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 543 IPSTATS_MIB_INHDRERRORS); 544 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 545 ((&hdr->segments_left) - 546 skb_network_header(skb))); 547 return -1; 548 } 549 550 /* We are about to mangle packet header. Be careful! 551 Do not damage packets queued somewhere. 552 */ 553 if (skb_cloned(skb)) { 554 /* the copy is a forwarded packet */ 555 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 556 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 557 IPSTATS_MIB_OUTDISCARDS); 558 kfree_skb(skb); 559 return -1; 560 } 561 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 562 } 563 564 if (skb->ip_summed == CHECKSUM_COMPLETE) 565 skb->ip_summed = CHECKSUM_NONE; 566 567 i = n - --hdr->segments_left; 568 569 rthdr = (struct rt0_hdr *) hdr; 570 addr = rthdr->addr; 571 addr += i - 1; 572 573 switch (hdr->type) { 574 #if IS_ENABLED(CONFIG_IPV6_MIP6) 575 case IPV6_SRCRT_TYPE_2: 576 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 577 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 578 IPPROTO_ROUTING) < 0) { 579 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 580 IPSTATS_MIB_INADDRERRORS); 581 kfree_skb(skb); 582 return -1; 583 } 584 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 585 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 586 IPSTATS_MIB_INADDRERRORS); 587 kfree_skb(skb); 588 return -1; 589 } 590 break; 591 #endif 592 default: 593 break; 594 } 595 596 if (ipv6_addr_is_multicast(addr)) { 597 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 598 IPSTATS_MIB_INADDRERRORS); 599 kfree_skb(skb); 600 return -1; 601 } 602 603 daddr = *addr; 604 *addr = ipv6_hdr(skb)->daddr; 605 ipv6_hdr(skb)->daddr = daddr; 606 607 skb_dst_drop(skb); 608 ip6_route_input(skb); 609 if (skb_dst(skb)->error) { 610 skb_push(skb, skb->data - skb_network_header(skb)); 611 dst_input(skb); 612 return -1; 613 } 614 615 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 616 if (ipv6_hdr(skb)->hop_limit <= 1) { 617 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 618 IPSTATS_MIB_INHDRERRORS); 619 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 620 0); 621 kfree_skb(skb); 622 return -1; 623 } 624 ipv6_hdr(skb)->hop_limit--; 625 goto looped_back; 626 } 627 628 skb_push(skb, skb->data - skb_network_header(skb)); 629 dst_input(skb); 630 return -1; 631 632 unknown_rh: 633 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); 634 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 635 (&hdr->type) - skb_network_header(skb)); 636 return -1; 637 } 638 639 static const struct inet6_protocol rthdr_protocol = { 640 .handler = ipv6_rthdr_rcv, 641 .flags = INET6_PROTO_NOPOLICY, 642 }; 643 644 static const struct inet6_protocol destopt_protocol = { 645 .handler = ipv6_destopt_rcv, 646 .flags = INET6_PROTO_NOPOLICY, 647 }; 648 649 static const struct inet6_protocol nodata_protocol = { 650 .handler = dst_discard, 651 .flags = INET6_PROTO_NOPOLICY, 652 }; 653 654 int __init ipv6_exthdrs_init(void) 655 { 656 int ret; 657 658 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 659 if (ret) 660 goto out; 661 662 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 663 if (ret) 664 goto out_rthdr; 665 666 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 667 if (ret) 668 goto out_destopt; 669 670 out: 671 return ret; 672 out_destopt: 673 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 674 out_rthdr: 675 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 676 goto out; 677 }; 678 679 void ipv6_exthdrs_exit(void) 680 { 681 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 682 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 683 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 684 } 685 686 /********************************** 687 Hop-by-hop options. 688 **********************************/ 689 690 /* 691 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 692 */ 693 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 694 { 695 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 696 } 697 698 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 699 { 700 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 701 } 702 703 /* Router Alert as of RFC 2711 */ 704 705 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 706 { 707 const unsigned char *nh = skb_network_header(skb); 708 709 if (nh[optoff + 1] == 2) { 710 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 711 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 712 return true; 713 } 714 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 715 nh[optoff + 1]); 716 kfree_skb(skb); 717 return false; 718 } 719 720 /* Jumbo payload */ 721 722 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 723 { 724 const unsigned char *nh = skb_network_header(skb); 725 struct net *net = ipv6_skb_net(skb); 726 u32 pkt_len; 727 728 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 729 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 730 nh[optoff+1]); 731 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 732 IPSTATS_MIB_INHDRERRORS); 733 goto drop; 734 } 735 736 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 737 if (pkt_len <= IPV6_MAXPLEN) { 738 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 739 IPSTATS_MIB_INHDRERRORS); 740 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 741 return false; 742 } 743 if (ipv6_hdr(skb)->payload_len) { 744 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 745 IPSTATS_MIB_INHDRERRORS); 746 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 747 return false; 748 } 749 750 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 751 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 752 IPSTATS_MIB_INTRUNCATEDPKTS); 753 goto drop; 754 } 755 756 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 757 goto drop; 758 759 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 760 return true; 761 762 drop: 763 kfree_skb(skb); 764 return false; 765 } 766 767 /* CALIPSO RFC 5570 */ 768 769 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 770 { 771 const unsigned char *nh = skb_network_header(skb); 772 773 if (nh[optoff + 1] < 8) 774 goto drop; 775 776 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 777 goto drop; 778 779 if (!calipso_validate(skb, nh + optoff)) 780 goto drop; 781 782 return true; 783 784 drop: 785 kfree_skb(skb); 786 return false; 787 } 788 789 static const struct tlvtype_proc tlvprochopopt_lst[] = { 790 { 791 .type = IPV6_TLV_ROUTERALERT, 792 .func = ipv6_hop_ra, 793 }, 794 { 795 .type = IPV6_TLV_JUMBO, 796 .func = ipv6_hop_jumbo, 797 }, 798 { 799 .type = IPV6_TLV_CALIPSO, 800 .func = ipv6_hop_calipso, 801 }, 802 { -1, } 803 }; 804 805 int ipv6_parse_hopopts(struct sk_buff *skb) 806 { 807 struct inet6_skb_parm *opt = IP6CB(skb); 808 809 /* 810 * skb_network_header(skb) is equal to skb->data, and 811 * skb_network_header_len(skb) is always equal to 812 * sizeof(struct ipv6hdr) by definition of 813 * hop-by-hop options. 814 */ 815 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 816 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 817 ((skb_transport_header(skb)[1] + 1) << 3)))) { 818 kfree_skb(skb); 819 return -1; 820 } 821 822 opt->flags |= IP6SKB_HOPBYHOP; 823 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) { 824 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 825 opt = IP6CB(skb); 826 opt->nhoff = sizeof(struct ipv6hdr); 827 return 1; 828 } 829 return -1; 830 } 831 832 /* 833 * Creating outbound headers. 834 * 835 * "build" functions work when skb is filled from head to tail (datagram) 836 * "push" functions work when headers are added from tail to head (tcp) 837 * 838 * In both cases we assume, that caller reserved enough room 839 * for headers. 840 */ 841 842 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 843 struct ipv6_rt_hdr *opt, 844 struct in6_addr **addr_p, struct in6_addr *saddr) 845 { 846 struct rt0_hdr *phdr, *ihdr; 847 int hops; 848 849 ihdr = (struct rt0_hdr *) opt; 850 851 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 852 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 853 854 hops = ihdr->rt_hdr.hdrlen >> 1; 855 856 if (hops > 1) 857 memcpy(phdr->addr, ihdr->addr + 1, 858 (hops - 1) * sizeof(struct in6_addr)); 859 860 phdr->addr[hops - 1] = **addr_p; 861 *addr_p = ihdr->addr; 862 863 phdr->rt_hdr.nexthdr = *proto; 864 *proto = NEXTHDR_ROUTING; 865 } 866 867 static void ipv6_push_rthdr4(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 ipv6_sr_hdr *sr_phdr, *sr_ihdr; 872 int plen, hops; 873 874 sr_ihdr = (struct ipv6_sr_hdr *)opt; 875 plen = (sr_ihdr->hdrlen + 1) << 3; 876 877 sr_phdr = skb_push(skb, plen); 878 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 879 880 hops = sr_ihdr->first_segment + 1; 881 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 882 (hops - 1) * sizeof(struct in6_addr)); 883 884 sr_phdr->segments[0] = **addr_p; 885 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 886 887 #ifdef CONFIG_IPV6_SEG6_HMAC 888 if (sr_has_hmac(sr_phdr)) { 889 struct net *net = NULL; 890 891 if (skb->dev) 892 net = dev_net(skb->dev); 893 else if (skb->sk) 894 net = sock_net(skb->sk); 895 896 WARN_ON(!net); 897 898 if (net) 899 seg6_push_hmac(net, saddr, sr_phdr); 900 } 901 #endif 902 903 sr_phdr->nexthdr = *proto; 904 *proto = NEXTHDR_ROUTING; 905 } 906 907 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 908 struct ipv6_rt_hdr *opt, 909 struct in6_addr **addr_p, struct in6_addr *saddr) 910 { 911 switch (opt->type) { 912 case IPV6_SRCRT_TYPE_0: 913 case IPV6_SRCRT_STRICT: 914 case IPV6_SRCRT_TYPE_2: 915 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 916 break; 917 case IPV6_SRCRT_TYPE_4: 918 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 919 break; 920 default: 921 break; 922 } 923 } 924 925 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 926 { 927 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 928 929 memcpy(h, opt, ipv6_optlen(opt)); 930 h->nexthdr = *proto; 931 *proto = type; 932 } 933 934 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 935 u8 *proto, 936 struct in6_addr **daddr, struct in6_addr *saddr) 937 { 938 if (opt->srcrt) { 939 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 940 /* 941 * IPV6_RTHDRDSTOPTS is ignored 942 * unless IPV6_RTHDR is set (RFC3542). 943 */ 944 if (opt->dst0opt) 945 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 946 } 947 if (opt->hopopt) 948 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 949 } 950 951 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 952 { 953 if (opt->dst1opt) 954 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 955 } 956 EXPORT_SYMBOL(ipv6_push_frag_opts); 957 958 struct ipv6_txoptions * 959 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 960 { 961 struct ipv6_txoptions *opt2; 962 963 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 964 if (opt2) { 965 long dif = (char *)opt2 - (char *)opt; 966 memcpy(opt2, opt, opt->tot_len); 967 if (opt2->hopopt) 968 *((char **)&opt2->hopopt) += dif; 969 if (opt2->dst0opt) 970 *((char **)&opt2->dst0opt) += dif; 971 if (opt2->dst1opt) 972 *((char **)&opt2->dst1opt) += dif; 973 if (opt2->srcrt) 974 *((char **)&opt2->srcrt) += dif; 975 refcount_set(&opt2->refcnt, 1); 976 } 977 return opt2; 978 } 979 EXPORT_SYMBOL_GPL(ipv6_dup_options); 980 981 static int ipv6_renew_option(void *ohdr, 982 struct ipv6_opt_hdr __user *newopt, int newoptlen, 983 int inherit, 984 struct ipv6_opt_hdr **hdr, 985 char **p) 986 { 987 if (inherit) { 988 if (ohdr) { 989 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); 990 *hdr = (struct ipv6_opt_hdr *)*p; 991 *p += CMSG_ALIGN(ipv6_optlen(*hdr)); 992 } 993 } else { 994 if (newopt) { 995 if (copy_from_user(*p, newopt, newoptlen)) 996 return -EFAULT; 997 *hdr = (struct ipv6_opt_hdr *)*p; 998 if (ipv6_optlen(*hdr) > newoptlen) 999 return -EINVAL; 1000 *p += CMSG_ALIGN(newoptlen); 1001 } 1002 } 1003 return 0; 1004 } 1005 1006 /** 1007 * ipv6_renew_options - replace a specific ext hdr with a new one. 1008 * 1009 * @sk: sock from which to allocate memory 1010 * @opt: original options 1011 * @newtype: option type to replace in @opt 1012 * @newopt: new option of type @newtype to replace (user-mem) 1013 * @newoptlen: length of @newopt 1014 * 1015 * Returns a new set of options which is a copy of @opt with the 1016 * option type @newtype replaced with @newopt. 1017 * 1018 * @opt may be NULL, in which case a new set of options is returned 1019 * containing just @newopt. 1020 * 1021 * @newopt may be NULL, in which case the specified option type is 1022 * not copied into the new set of options. 1023 * 1024 * The new set of options is allocated from the socket option memory 1025 * buffer of @sk. 1026 */ 1027 struct ipv6_txoptions * 1028 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1029 int newtype, 1030 struct ipv6_opt_hdr __user *newopt, int newoptlen) 1031 { 1032 int tot_len = 0; 1033 char *p; 1034 struct ipv6_txoptions *opt2; 1035 int err; 1036 1037 if (opt) { 1038 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1039 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1040 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1041 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1042 if (newtype != IPV6_RTHDR && opt->srcrt) 1043 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1044 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1045 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1046 } 1047 1048 if (newopt && newoptlen) 1049 tot_len += CMSG_ALIGN(newoptlen); 1050 1051 if (!tot_len) 1052 return NULL; 1053 1054 tot_len += sizeof(*opt2); 1055 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1056 if (!opt2) 1057 return ERR_PTR(-ENOBUFS); 1058 1059 memset(opt2, 0, tot_len); 1060 refcount_set(&opt2->refcnt, 1); 1061 opt2->tot_len = tot_len; 1062 p = (char *)(opt2 + 1); 1063 1064 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, 1065 newtype != IPV6_HOPOPTS, 1066 &opt2->hopopt, &p); 1067 if (err) 1068 goto out; 1069 1070 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, 1071 newtype != IPV6_RTHDRDSTOPTS, 1072 &opt2->dst0opt, &p); 1073 if (err) 1074 goto out; 1075 1076 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, 1077 newtype != IPV6_RTHDR, 1078 (struct ipv6_opt_hdr **)&opt2->srcrt, &p); 1079 if (err) 1080 goto out; 1081 1082 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, 1083 newtype != IPV6_DSTOPTS, 1084 &opt2->dst1opt, &p); 1085 if (err) 1086 goto out; 1087 1088 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1089 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1090 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1091 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1092 1093 return opt2; 1094 out: 1095 sock_kfree_s(sk, opt2, opt2->tot_len); 1096 return ERR_PTR(err); 1097 } 1098 1099 /** 1100 * ipv6_renew_options_kern - replace a specific ext hdr with a new one. 1101 * 1102 * @sk: sock from which to allocate memory 1103 * @opt: original options 1104 * @newtype: option type to replace in @opt 1105 * @newopt: new option of type @newtype to replace (kernel-mem) 1106 * @newoptlen: length of @newopt 1107 * 1108 * See ipv6_renew_options(). The difference is that @newopt is 1109 * kernel memory, rather than user memory. 1110 */ 1111 struct ipv6_txoptions * 1112 ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt, 1113 int newtype, struct ipv6_opt_hdr *newopt, 1114 int newoptlen) 1115 { 1116 struct ipv6_txoptions *ret_val; 1117 const mm_segment_t old_fs = get_fs(); 1118 1119 set_fs(KERNEL_DS); 1120 ret_val = ipv6_renew_options(sk, opt, newtype, 1121 (struct ipv6_opt_hdr __user *)newopt, 1122 newoptlen); 1123 set_fs(old_fs); 1124 return ret_val; 1125 } 1126 1127 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1128 struct ipv6_txoptions *opt) 1129 { 1130 /* 1131 * ignore the dest before srcrt unless srcrt is being included. 1132 * --yoshfuji 1133 */ 1134 if (opt && opt->dst0opt && !opt->srcrt) { 1135 if (opt_space != opt) { 1136 memcpy(opt_space, opt, sizeof(*opt_space)); 1137 opt = opt_space; 1138 } 1139 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1140 opt->dst0opt = NULL; 1141 } 1142 1143 return opt; 1144 } 1145 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1146 1147 /** 1148 * fl6_update_dst - update flowi destination address with info given 1149 * by srcrt option, if any. 1150 * 1151 * @fl6: flowi6 for which daddr is to be updated 1152 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1153 * @orig: copy of original daddr address if modified 1154 * 1155 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1156 * and initial value of fl6->daddr set in orig 1157 */ 1158 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1159 const struct ipv6_txoptions *opt, 1160 struct in6_addr *orig) 1161 { 1162 if (!opt || !opt->srcrt) 1163 return NULL; 1164 1165 *orig = fl6->daddr; 1166 1167 switch (opt->srcrt->type) { 1168 case IPV6_SRCRT_TYPE_0: 1169 case IPV6_SRCRT_STRICT: 1170 case IPV6_SRCRT_TYPE_2: 1171 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1172 break; 1173 case IPV6_SRCRT_TYPE_4: 1174 { 1175 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1176 1177 fl6->daddr = srh->segments[srh->segments_left]; 1178 break; 1179 } 1180 default: 1181 return NULL; 1182 } 1183 1184 return orig; 1185 } 1186 EXPORT_SYMBOL_GPL(fl6_update_dst); 1187