1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting 5 * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 /* 33 * IPsec output processing. 34 */ 35 #include "opt_inet.h" 36 #include "opt_inet6.h" 37 #include "opt_ipsec.h" 38 #include "opt_sctp.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/domain.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/errno.h> 47 #include <sys/hhook.h> 48 #include <sys/syslog.h> 49 50 #include <net/if.h> 51 #include <net/if_enc.h> 52 #include <net/if_var.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_var.h> 59 #include <netinet/in_var.h> 60 #include <netinet/ip_ecn.h> 61 #ifdef INET6 62 #include <netinet6/ip6_ecn.h> 63 #endif 64 #include <netinet/ip_icmp.h> 65 #include <netinet/tcp_var.h> 66 67 #include <netinet/ip6.h> 68 #ifdef INET6 69 #include <netinet6/ip6_var.h> 70 #include <netinet6/scope6_var.h> 71 #endif 72 #include <netinet/in_pcb.h> 73 #ifdef INET6 74 #include <netinet/icmp6.h> 75 #endif 76 #if defined(SCTP) || defined(SCTP_SUPPORT) 77 #include <netinet/sctp_crc32.h> 78 #endif 79 80 #include <netinet/udp.h> 81 #include <netipsec/ah.h> 82 #include <netipsec/esp.h> 83 #include <netipsec/ipsec.h> 84 #ifdef INET6 85 #include <netipsec/ipsec6.h> 86 #endif 87 #include <netipsec/ah_var.h> 88 #include <netipsec/esp_var.h> 89 #include <netipsec/ipcomp_var.h> 90 91 #include <netipsec/xform.h> 92 93 #include <netipsec/key.h> 94 #include <netipsec/keydb.h> 95 #include <netipsec/key_debug.h> 96 97 #include <machine/in_cksum.h> 98 99 #define IPSEC_OSTAT_INC(proto, name) do { \ 100 if ((proto) == IPPROTO_ESP) \ 101 ESPSTAT_INC(esps_##name); \ 102 else if ((proto) == IPPROTO_AH)\ 103 AHSTAT_INC(ahs_##name); \ 104 else \ 105 IPCOMPSTAT_INC(ipcomps_##name); \ 106 } while (0) 107 108 static int ipsec_encap(struct mbuf **mp, struct secasindex *saidx); 109 static size_t ipsec_get_pmtu(struct secasvar *sav); 110 111 #ifdef INET 112 static struct secasvar * 113 ipsec4_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 114 { 115 struct secasindex *saidx, tmpsaidx; 116 struct ipsecrequest *isr; 117 struct sockaddr_in *sin; 118 struct secasvar *sav; 119 struct ip *ip; 120 121 /* 122 * Check system global policy controls. 123 */ 124 next: 125 isr = sp->req[*pidx]; 126 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 127 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 128 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 129 DPRINTF(("%s: IPsec outbound packet dropped due" 130 " to policy (check your sysctls)\n", __func__)); 131 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 132 *error = EHOSTUNREACH; 133 return (NULL); 134 } 135 /* 136 * Craft SA index to search for proper SA. Note that 137 * we only initialize unspecified SA peers for transport 138 * mode; for tunnel mode they must already be filled in. 139 */ 140 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 141 saidx = &tmpsaidx; 142 *saidx = isr->saidx; 143 ip = mtod(m, struct ip *); 144 if (saidx->src.sa.sa_len == 0) { 145 sin = &saidx->src.sin; 146 sin->sin_len = sizeof(*sin); 147 sin->sin_family = AF_INET; 148 sin->sin_port = IPSEC_PORT_ANY; 149 sin->sin_addr = ip->ip_src; 150 } 151 if (saidx->dst.sa.sa_len == 0) { 152 sin = &saidx->dst.sin; 153 sin->sin_len = sizeof(*sin); 154 sin->sin_family = AF_INET; 155 sin->sin_port = IPSEC_PORT_ANY; 156 sin->sin_addr = ip->ip_dst; 157 } 158 } else 159 saidx = &sp->req[*pidx]->saidx; 160 /* 161 * Lookup SA and validate it. 162 */ 163 sav = key_allocsa_policy(sp, saidx, error); 164 if (sav == NULL) { 165 IPSECSTAT_INC(ips_out_nosa); 166 if (*error != 0) 167 return (NULL); 168 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 169 /* 170 * We have no SA and policy that doesn't require 171 * this IPsec transform, thus we can continue w/o 172 * IPsec processing, i.e. return EJUSTRETURN. 173 * But first check if there is some bundled transform. 174 */ 175 if (sp->tcount > ++(*pidx)) 176 goto next; 177 *error = EJUSTRETURN; 178 } 179 return (NULL); 180 } 181 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 182 return (sav); 183 } 184 185 /* 186 * IPsec output logic for IPv4. 187 */ 188 static int 189 ipsec4_perform_request(struct mbuf *m, struct secpolicy *sp, 190 struct inpcb *inp, u_int idx) 191 { 192 struct ipsec_ctx_data ctx; 193 union sockaddr_union *dst; 194 struct secasvar *sav; 195 struct ip *ip; 196 int error, i, off; 197 198 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 199 200 /* 201 * We hold the reference to SP. Content of SP couldn't be changed. 202 * Craft secasindex and do lookup for suitable SA. 203 * Then do encapsulation if needed and call xform's output. 204 * We need to store SP in the xform callback parameters. 205 * In xform callback we will extract SP and it can be used to 206 * determine next transform. At the end of transform we can 207 * release reference to SP. 208 */ 209 sav = ipsec4_allocsa(m, sp, &idx, &error); 210 if (sav == NULL) { 211 if (error == EJUSTRETURN) { /* No IPsec required */ 212 key_freesp(&sp); 213 return (error); 214 } 215 goto bad; 216 } 217 /* 218 * XXXAE: most likely ip_sum at this point is wrong. 219 */ 220 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET, IPSEC_ENC_BEFORE); 221 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 222 goto bad; 223 224 ip = mtod(m, struct ip *); 225 dst = &sav->sah->saidx.dst; 226 /* Do the appropriate encapsulation, if necessary */ 227 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 228 dst->sa.sa_family != AF_INET || /* PF mismatch */ 229 (dst->sa.sa_family == AF_INET && /* Proxy */ 230 dst->sin.sin_addr.s_addr != INADDR_ANY && 231 dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) { 232 /* Fix IPv4 header checksum and length */ 233 ip->ip_len = htons(m->m_pkthdr.len); 234 ip->ip_sum = 0; 235 ip->ip_sum = in_cksum(m, ip->ip_hl << 2); 236 error = ipsec_encap(&m, &sav->sah->saidx); 237 if (error != 0) { 238 DPRINTF(("%s: encapsulation for SPI 0x%08x failed " 239 "with error %d\n", __func__, ntohl(sav->spi), 240 error)); 241 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 242 goto bad; 243 } 244 inp = NULL; 245 } 246 247 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 248 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 249 goto bad; 250 251 /* 252 * Dispatch to the appropriate IPsec transform logic. The 253 * packet will be returned for transmission after crypto 254 * processing, etc. are completed. 255 * 256 * NB: m & sav are ``passed to caller'' who's responsible for 257 * reclaiming their resources. 258 */ 259 switch(dst->sa.sa_family) { 260 case AF_INET: 261 ip = mtod(m, struct ip *); 262 i = ip->ip_hl << 2; 263 off = offsetof(struct ip, ip_p); 264 break; 265 #ifdef INET6 266 case AF_INET6: 267 i = sizeof(struct ip6_hdr); 268 off = offsetof(struct ip6_hdr, ip6_nxt); 269 break; 270 #endif /* INET6 */ 271 default: 272 DPRINTF(("%s: unsupported protocol family %u\n", 273 __func__, dst->sa.sa_family)); 274 error = EPFNOSUPPORT; 275 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 276 goto bad; 277 } 278 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 279 return (error); 280 bad: 281 IPSECSTAT_INC(ips_out_inval); 282 if (m != NULL) 283 m_freem(m); 284 if (sav != NULL) 285 key_freesav(&sav); 286 key_freesp(&sp); 287 return (error); 288 } 289 290 int 291 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp, 292 struct inpcb *inp) 293 { 294 295 return (ipsec4_perform_request(m, sp, inp, 0)); 296 } 297 298 int 299 ipsec4_check_pmtu(struct mbuf *m, struct secpolicy *sp, int forwarding) 300 { 301 struct secasvar *sav; 302 struct ip *ip; 303 size_t hlen, pmtu; 304 uint32_t idx; 305 int error; 306 307 /* Don't check PMTU if the frame won't have DF bit set. */ 308 if (!V_ip4_ipsec_dfbit) 309 return (0); 310 if (V_ip4_ipsec_dfbit == 1) 311 goto setdf; 312 313 /* V_ip4_ipsec_dfbit > 1 - we will copy it from inner header. */ 314 ip = mtod(m, struct ip *); 315 if (!(ip->ip_off & htons(IP_DF))) 316 return (0); 317 318 setdf: 319 idx = sp->tcount - 1; 320 sav = ipsec4_allocsa(m, sp, &idx, &error); 321 if (sav == NULL) { 322 key_freesp(&sp); 323 /* 324 * No matching SA was found and SADB_ACQUIRE message was generated. 325 * Since we have matched a SP to this packet drop it silently. 326 */ 327 if (error == 0) 328 error = EINPROGRESS; 329 if (error != EJUSTRETURN) 330 m_freem(m); 331 332 return (error); 333 } 334 335 pmtu = ipsec_get_pmtu(sav); 336 if (pmtu == 0) { 337 key_freesav(&sav); 338 return (0); 339 } 340 341 hlen = ipsec_hdrsiz_internal(sp); 342 key_freesav(&sav); 343 344 if (m_length(m, NULL) + hlen > pmtu) { 345 /* 346 * If we're forwarding generate ICMP message here, 347 * so that it contains pmtu subtracted by header size. 348 * Set error to EINPROGRESS, in order for the frame 349 * to be dropped silently. 350 */ 351 if (forwarding) { 352 if (pmtu > hlen) 353 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 354 0, pmtu - hlen); 355 else 356 m_freem(m); 357 358 key_freesp(&sp); 359 return (EINPROGRESS); /* Pretend that we consumed it. */ 360 } else { 361 m_freem(m); 362 key_freesp(&sp); 363 return (EMSGSIZE); 364 } 365 } 366 367 return (0); 368 } 369 370 static int 371 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 372 { 373 struct secpolicy *sp; 374 int error; 375 376 /* Lookup for the corresponding outbound security policy */ 377 sp = ipsec4_checkpolicy(m, inp, &error, !forwarding); 378 if (sp == NULL) { 379 if (error == -EINVAL) { 380 /* Discarded by policy. */ 381 m_freem(m); 382 return (EACCES); 383 } 384 return (0); /* No IPsec required. */ 385 } 386 387 /* 388 * Usually we have to have tunnel mode IPsec security policy 389 * when we are forwarding a packet. Otherwise we could not handle 390 * encrypted replies, because they are not destined for us. But 391 * some users are doing source address translation for forwarded 392 * packets, and thus, even if they are forwarded, the replies will 393 * return back to us. 394 */ 395 if (!forwarding) { 396 /* 397 * Do delayed checksums now because we send before 398 * this is done in the normal processing path. 399 */ 400 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 401 m = mb_unmapped_to_ext(m); 402 if (m == NULL) { 403 IPSECSTAT_INC(ips_out_nomem); 404 key_freesp(&sp); 405 return (ENOBUFS); 406 } 407 in_delayed_cksum(m); 408 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 409 } 410 #if defined(SCTP) || defined(SCTP_SUPPORT) 411 if (m->m_pkthdr.csum_flags & CSUM_SCTP) { 412 struct ip *ip; 413 414 m = mb_unmapped_to_ext(m); 415 if (m == NULL) { 416 IPSECSTAT_INC(ips_out_nomem); 417 key_freesp(&sp); 418 return (ENOBUFS); 419 } 420 ip = mtod(m, struct ip *); 421 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 422 m->m_pkthdr.csum_flags &= ~CSUM_SCTP; 423 } 424 #endif 425 } 426 /* NB: callee frees mbuf and releases reference to SP */ 427 error = ipsec4_check_pmtu(m, sp, forwarding); 428 if (error != 0) { 429 if (error == EJUSTRETURN) 430 return (0); 431 432 return (error); 433 } 434 435 error = ipsec4_process_packet(m, sp, inp); 436 if (error == EJUSTRETURN) { 437 /* 438 * We had a SP with a level of 'use' and no SA. We 439 * will just continue to process the packet without 440 * IPsec processing and return without error. 441 */ 442 return (0); 443 } 444 if (error == 0) 445 return (EINPROGRESS); /* consumed by IPsec */ 446 return (error); 447 } 448 449 /* 450 * IPSEC_OUTPUT() method implementation for IPv4. 451 * 0 - no IPsec handling needed 452 * other values - mbuf consumed by IPsec. 453 */ 454 int 455 ipsec4_output(struct mbuf *m, struct inpcb *inp) 456 { 457 458 /* 459 * If the packet is resubmitted to ip_output (e.g. after 460 * AH, ESP, etc. processing), there will be a tag to bypass 461 * the lookup and related policy checking. 462 */ 463 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 464 return (0); 465 466 return (ipsec4_common_output(m, inp, 0)); 467 } 468 469 /* 470 * IPSEC_FORWARD() method implementation for IPv4. 471 * 0 - no IPsec handling needed 472 * other values - mbuf consumed by IPsec. 473 */ 474 int 475 ipsec4_forward(struct mbuf *m) 476 { 477 478 /* 479 * Check if this packet has an active inbound SP and needs to be 480 * dropped instead of forwarded. 481 */ 482 if (ipsec4_in_reject(m, NULL) != 0) { 483 m_freem(m); 484 return (EACCES); 485 } 486 return (ipsec4_common_output(m, NULL, 1)); 487 } 488 #endif 489 490 #ifdef INET6 491 static int 492 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa, 493 const struct in6_addr *ia) 494 { 495 struct in6_addr ia2; 496 497 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) { 498 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2)); 499 ia2.s6_addr16[1] = htons(sa->sin6_scope_id); 500 return (IN6_ARE_ADDR_EQUAL(ia, &ia2)); 501 } 502 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia)); 503 } 504 505 static struct secasvar * 506 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 507 { 508 struct secasindex *saidx, tmpsaidx; 509 struct ipsecrequest *isr; 510 struct sockaddr_in6 *sin6; 511 struct secasvar *sav; 512 struct ip6_hdr *ip6; 513 514 /* 515 * Check system global policy controls. 516 */ 517 next: 518 isr = sp->req[*pidx]; 519 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 520 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 521 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 522 DPRINTF(("%s: IPsec outbound packet dropped due" 523 " to policy (check your sysctls)\n", __func__)); 524 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 525 *error = EHOSTUNREACH; 526 return (NULL); 527 } 528 /* 529 * Craft SA index to search for proper SA. Note that 530 * we only fillin unspecified SA peers for transport 531 * mode; for tunnel mode they must already be filled in. 532 */ 533 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 534 saidx = &tmpsaidx; 535 *saidx = isr->saidx; 536 ip6 = mtod(m, struct ip6_hdr *); 537 if (saidx->src.sin6.sin6_len == 0) { 538 sin6 = (struct sockaddr_in6 *)&saidx->src; 539 sin6->sin6_len = sizeof(*sin6); 540 sin6->sin6_family = AF_INET6; 541 sin6->sin6_port = IPSEC_PORT_ANY; 542 sin6->sin6_addr = ip6->ip6_src; 543 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 544 /* fix scope id for comparing SPD */ 545 sin6->sin6_addr.s6_addr16[1] = 0; 546 sin6->sin6_scope_id = 547 ntohs(ip6->ip6_src.s6_addr16[1]); 548 } 549 } 550 if (saidx->dst.sin6.sin6_len == 0) { 551 sin6 = (struct sockaddr_in6 *)&saidx->dst; 552 sin6->sin6_len = sizeof(*sin6); 553 sin6->sin6_family = AF_INET6; 554 sin6->sin6_port = IPSEC_PORT_ANY; 555 sin6->sin6_addr = ip6->ip6_dst; 556 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 557 /* fix scope id for comparing SPD */ 558 sin6->sin6_addr.s6_addr16[1] = 0; 559 sin6->sin6_scope_id = 560 ntohs(ip6->ip6_dst.s6_addr16[1]); 561 } 562 } 563 } else 564 saidx = &sp->req[*pidx]->saidx; 565 /* 566 * Lookup SA and validate it. 567 */ 568 sav = key_allocsa_policy(sp, saidx, error); 569 if (sav == NULL) { 570 IPSEC6STAT_INC(ips_out_nosa); 571 if (*error != 0) 572 return (NULL); 573 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 574 /* 575 * We have no SA and policy that doesn't require 576 * this IPsec transform, thus we can continue w/o 577 * IPsec processing, i.e. return EJUSTRETURN. 578 * But first check if there is some bundled transform. 579 */ 580 if (sp->tcount > ++(*pidx)) 581 goto next; 582 *error = EJUSTRETURN; 583 } 584 return (NULL); 585 } 586 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 587 return (sav); 588 } 589 590 /* 591 * IPsec output logic for IPv6. 592 */ 593 static int 594 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp, 595 struct inpcb *inp, u_int idx) 596 { 597 struct ipsec_ctx_data ctx; 598 union sockaddr_union *dst; 599 struct secasvar *sav; 600 struct ip6_hdr *ip6; 601 int error, i, off; 602 603 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 604 605 sav = ipsec6_allocsa(m, sp, &idx, &error); 606 if (sav == NULL) { 607 if (error == EJUSTRETURN) { /* No IPsec required */ 608 key_freesp(&sp); 609 return (error); 610 } 611 goto bad; 612 } 613 614 /* Fix IP length in case if it is not set yet. */ 615 ip6 = mtod(m, struct ip6_hdr *); 616 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); 617 618 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE); 619 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 620 goto bad; 621 622 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */ 623 dst = &sav->sah->saidx.dst; 624 625 /* Do the appropriate encapsulation, if necessary */ 626 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 627 dst->sa.sa_family != AF_INET6 || /* PF mismatch */ 628 ((dst->sa.sa_family == AF_INET6) && 629 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) && 630 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) { 631 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) { 632 /* No jumbogram support. */ 633 error = ENXIO; /*XXX*/ 634 goto bad; 635 } 636 error = ipsec_encap(&m, &sav->sah->saidx); 637 if (error != 0) { 638 DPRINTF(("%s: encapsulation for SPI 0x%08x failed " 639 "with error %d\n", __func__, ntohl(sav->spi), 640 error)); 641 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 642 goto bad; 643 } 644 inp = NULL; 645 } 646 647 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 648 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 649 goto bad; 650 651 switch(dst->sa.sa_family) { 652 #ifdef INET 653 case AF_INET: 654 { 655 struct ip *ip; 656 ip = mtod(m, struct ip *); 657 i = ip->ip_hl << 2; 658 off = offsetof(struct ip, ip_p); 659 } 660 break; 661 #endif /* AF_INET */ 662 case AF_INET6: 663 i = sizeof(struct ip6_hdr); 664 off = offsetof(struct ip6_hdr, ip6_nxt); 665 break; 666 default: 667 DPRINTF(("%s: unsupported protocol family %u\n", 668 __func__, dst->sa.sa_family)); 669 error = EPFNOSUPPORT; 670 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 671 goto bad; 672 } 673 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 674 return (error); 675 bad: 676 IPSEC6STAT_INC(ips_out_inval); 677 if (m != NULL) 678 m_freem(m); 679 if (sav != NULL) 680 key_freesav(&sav); 681 key_freesp(&sp); 682 return (error); 683 } 684 685 int 686 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp, 687 struct inpcb *inp) 688 { 689 690 return (ipsec6_perform_request(m, sp, inp, 0)); 691 } 692 693 /* 694 * IPv6 implementation is based on IPv4 implementation. 695 */ 696 int 697 ipsec6_check_pmtu(struct mbuf *m, struct secpolicy *sp, int forwarding) 698 { 699 struct secasvar *sav; 700 size_t hlen, pmtu; 701 uint32_t idx; 702 int error; 703 704 /* 705 * According to RFC8200 L3 fragmentation is supposed to be done only on 706 * locally generated packets. During L3 forwarding packets that are too 707 * big are always supposed to be dropped, with an ICMPv6 packet being 708 * sent back. 709 */ 710 if (!forwarding) 711 return (0); 712 713 idx = sp->tcount - 1; 714 sav = ipsec6_allocsa(m, sp, &idx, &error); 715 if (sav == NULL) { 716 key_freesp(&sp); 717 /* 718 * No matching SA was found and SADB_ACQUIRE message was generated. 719 * Since we have matched a SP to this packet drop it silently. 720 */ 721 if (error == 0) 722 error = EINPROGRESS; 723 if (error != EJUSTRETURN) 724 m_freem(m); 725 726 return (error); 727 } 728 729 pmtu = ipsec_get_pmtu(sav); 730 if (pmtu == 0) { 731 key_freesav(&sav); 732 return (0); 733 } 734 735 hlen = ipsec_hdrsiz_internal(sp); 736 key_freesav(&sav); 737 738 if (m_length(m, NULL) + hlen > pmtu) { 739 /* 740 * If we're forwarding generate ICMPv6 message here, 741 * so that it contains pmtu subtracted by header size. 742 * Set error to EINPROGRESS, in order for the frame 743 * to be dropped silently. 744 */ 745 if (forwarding) { 746 if (pmtu > hlen) 747 icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, pmtu - hlen); 748 else 749 m_freem(m); 750 751 key_freesp(&sp); 752 return (EINPROGRESS); /* Pretend that we consumed it. */ 753 } 754 } 755 756 return (0); 757 } 758 759 static int 760 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 761 { 762 struct secpolicy *sp; 763 int error; 764 765 /* Lookup for the corresponding outbound security policy */ 766 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding); 767 if (sp == NULL) { 768 if (error == -EINVAL) { 769 /* Discarded by policy. */ 770 m_freem(m); 771 return (EACCES); 772 } 773 return (0); /* No IPsec required. */ 774 } 775 776 if (!forwarding) { 777 /* 778 * Do delayed checksums now because we send before 779 * this is done in the normal processing path. 780 */ 781 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 782 m = mb_unmapped_to_ext(m); 783 if (m == NULL) { 784 IPSEC6STAT_INC(ips_out_nomem); 785 key_freesp(&sp); 786 return (ENOBUFS); 787 } 788 in6_delayed_cksum(m, m->m_pkthdr.len - 789 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr)); 790 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 791 } 792 #if defined(SCTP) || defined(SCTP_SUPPORT) 793 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 794 m = mb_unmapped_to_ext(m); 795 if (m == NULL) { 796 IPSEC6STAT_INC(ips_out_nomem); 797 key_freesp(&sp); 798 return (ENOBUFS); 799 } 800 sctp_delayed_cksum(m, sizeof(struct ip6_hdr)); 801 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 802 } 803 #endif 804 } 805 806 error = ipsec6_check_pmtu(m, sp, forwarding); 807 if (error != 0) { 808 if (error == EJUSTRETURN) 809 return (0); 810 811 return (error); 812 } 813 814 /* NB: callee frees mbuf and releases reference to SP */ 815 error = ipsec6_process_packet(m, sp, inp); 816 if (error == EJUSTRETURN) { 817 /* 818 * We had a SP with a level of 'use' and no SA. We 819 * will just continue to process the packet without 820 * IPsec processing and return without error. 821 */ 822 return (0); 823 } 824 if (error == 0) 825 return (EINPROGRESS); /* consumed by IPsec */ 826 return (error); 827 } 828 829 /* 830 * IPSEC_OUTPUT() method implementation for IPv6. 831 * 0 - no IPsec handling needed 832 * other values - mbuf consumed by IPsec. 833 */ 834 int 835 ipsec6_output(struct mbuf *m, struct inpcb *inp) 836 { 837 838 /* 839 * If the packet is resubmitted to ip_output (e.g. after 840 * AH, ESP, etc. processing), there will be a tag to bypass 841 * the lookup and related policy checking. 842 */ 843 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 844 return (0); 845 846 return (ipsec6_common_output(m, inp, 0)); 847 } 848 849 /* 850 * IPSEC_FORWARD() method implementation for IPv6. 851 * 0 - no IPsec handling needed 852 * other values - mbuf consumed by IPsec. 853 */ 854 int 855 ipsec6_forward(struct mbuf *m) 856 { 857 858 /* 859 * Check if this packet has an active inbound SP and needs to be 860 * dropped instead of forwarded. 861 */ 862 if (ipsec6_in_reject(m, NULL) != 0) { 863 m_freem(m); 864 return (EACCES); 865 } 866 return (ipsec6_common_output(m, NULL, 1)); 867 } 868 #endif /* INET6 */ 869 870 int 871 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 872 u_int idx) 873 { 874 struct epoch_tracker et; 875 struct xform_history *xh; 876 struct secasindex *saidx; 877 struct m_tag *mtag; 878 int error; 879 880 saidx = &sav->sah->saidx; 881 switch (saidx->dst.sa.sa_family) { 882 #ifdef INET 883 case AF_INET: 884 /* Fix the header length, for AH processing. */ 885 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len); 886 break; 887 #endif /* INET */ 888 #ifdef INET6 889 case AF_INET6: 890 /* Fix the header length, for AH processing. */ 891 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) { 892 error = ENXIO; 893 goto bad; 894 } 895 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) { 896 /* No jumbogram support. */ 897 error = ENXIO; /*?*/ 898 goto bad; 899 } 900 mtod(m, struct ip6_hdr *)->ip6_plen = 901 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); 902 break; 903 #endif /* INET6 */ 904 default: 905 DPRINTF(("%s: unknown protocol family %u\n", __func__, 906 saidx->dst.sa.sa_family)); 907 error = ENXIO; 908 goto bad; 909 } 910 911 /* 912 * Add a record of what we've done to the packet. 913 */ 914 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT); 915 if (mtag == NULL) { 916 DPRINTF(("%s: could not get packet tag\n", __func__)); 917 error = ENOMEM; 918 goto bad; 919 } 920 921 xh = (struct xform_history *)(mtag + 1); 922 xh->dst = saidx->dst; 923 xh->proto = saidx->proto; 924 xh->mode = saidx->mode; 925 xh->spi = sav->spi; 926 m_tag_prepend(m, mtag); 927 928 key_sa_recordxfer(sav, m); /* record data transfer */ 929 930 /* 931 * If there's another (bundled) SA to apply, do so. 932 * Note that this puts a burden on the kernel stack size. 933 * If this is a problem we'll need to introduce a queue 934 * to set the packet on so we can unwind the stack before 935 * doing further processing. 936 */ 937 if (++idx < sp->tcount) { 938 switch (saidx->dst.sa.sa_family) { 939 #ifdef INET 940 case AF_INET: 941 key_freesav(&sav); 942 IPSECSTAT_INC(ips_out_bundlesa); 943 return (ipsec4_perform_request(m, sp, NULL, idx)); 944 /* NOTREACHED */ 945 #endif 946 #ifdef INET6 947 case AF_INET6: 948 key_freesav(&sav); 949 IPSEC6STAT_INC(ips_out_bundlesa); 950 return (ipsec6_perform_request(m, sp, NULL, idx)); 951 /* NOTREACHED */ 952 #endif /* INET6 */ 953 default: 954 DPRINTF(("%s: unknown protocol family %u\n", __func__, 955 saidx->dst.sa.sa_family)); 956 error = EPFNOSUPPORT; 957 goto bad; 958 } 959 } 960 961 key_freesp(&sp), sp = NULL; /* Release reference to SP */ 962 #ifdef INET 963 /* 964 * Do UDP encapsulation if SA requires it. 965 */ 966 if (sav->natt != NULL) { 967 error = udp_ipsec_output(m, sav); 968 if (error != 0) 969 goto bad; 970 } 971 #endif /* INET */ 972 /* 973 * We're done with IPsec processing, transmit the packet using the 974 * appropriate network protocol (IP or IPv6). 975 */ 976 NET_EPOCH_ENTER(et); 977 switch (saidx->dst.sa.sa_family) { 978 #ifdef INET 979 case AF_INET: 980 key_freesav(&sav); 981 error = ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL); 982 break; 983 #endif /* INET */ 984 #ifdef INET6 985 case AF_INET6: 986 key_freesav(&sav); 987 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 988 break; 989 #endif /* INET6 */ 990 default: 991 panic("ipsec_process_done"); 992 } 993 NET_EPOCH_EXIT(et); 994 return (error); 995 bad: 996 m_freem(m); 997 key_freesav(&sav); 998 if (sp != NULL) 999 key_freesp(&sp); 1000 return (error); 1001 } 1002 1003 /* 1004 * ipsec_prepend() is optimized version of M_PREPEND(). 1005 * ipsec_encap() is called by IPsec output routine for tunnel mode SA. 1006 * It is expected that after IP encapsulation some IPsec transform will 1007 * be performed. Each IPsec transform inserts its variable length header 1008 * just after outer IP header using m_makespace(). If given mbuf has not 1009 * enough free space at the beginning, we allocate new mbuf and reserve 1010 * some space at the beginning and at the end. 1011 * This helps avoid allocating of new mbuf and data copying in m_makespace(), 1012 * we place outer header in the middle of mbuf's data with reserved leading 1013 * and trailing space: 1014 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ] 1015 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will 1016 * be used to inject AH/ESP/IPCOMP header. 1017 */ 1018 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \ 1019 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \ 1020 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */)) 1021 static struct mbuf * 1022 ipsec_prepend(struct mbuf *m, int len, int how) 1023 { 1024 struct mbuf *n; 1025 1026 M_ASSERTPKTHDR(m); 1027 IPSEC_ASSERT(len < MHLEN, ("wrong length")); 1028 if (M_LEADINGSPACE(m) >= len) { 1029 /* No need to allocate new mbuf. */ 1030 m->m_data -= len; 1031 m->m_len += len; 1032 m->m_pkthdr.len += len; 1033 return (m); 1034 } 1035 n = m_gethdr(how, m->m_type); 1036 if (n == NULL) { 1037 m_freem(m); 1038 return (NULL); 1039 } 1040 m_move_pkthdr(n, m); 1041 n->m_next = m; 1042 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n)) 1043 m_align(n, len + IPSEC_TRAILINGSPACE); 1044 n->m_len = len; 1045 n->m_pkthdr.len += len; 1046 return (n); 1047 } 1048 1049 static size_t 1050 ipsec_get_pmtu(struct secasvar *sav) 1051 { 1052 union sockaddr_union *dst; 1053 struct in_conninfo inc; 1054 size_t pmtu; 1055 1056 dst = &sav->sah->saidx.dst; 1057 memset(&inc, 0, sizeof(inc)); 1058 1059 switch (dst->sa.sa_family) { 1060 #ifdef INET 1061 case AF_INET: 1062 inc.inc_faddr = satosin(&dst->sa)->sin_addr; 1063 break; 1064 #endif 1065 #ifdef INET6 1066 case AF_INET6: 1067 inc.inc6_faddr = satosin6(&dst->sa)->sin6_addr; 1068 inc.inc_flags |= INC_ISIPV6; 1069 break; 1070 #endif 1071 default: 1072 return (0); 1073 } 1074 1075 pmtu = tcp_hc_getmtu(&inc); 1076 if (pmtu != 0) 1077 return (pmtu); 1078 1079 /* No entry in hostcache. Assume that PMTU is equal to link's MTU */ 1080 switch (dst->sa.sa_family) { 1081 #ifdef INET 1082 case AF_INET: 1083 pmtu = tcp_maxmtu(&inc, NULL); 1084 break; 1085 #endif 1086 #ifdef INET6 1087 case AF_INET6: 1088 pmtu = tcp_maxmtu6(&inc, NULL); 1089 break; 1090 #endif 1091 default: 1092 return (0); 1093 } 1094 if (pmtu == 0) 1095 return (0); 1096 1097 tcp_hc_updatemtu(&inc, pmtu); 1098 1099 return (pmtu); 1100 } 1101 1102 static int 1103 ipsec_encap(struct mbuf **mp, struct secasindex *saidx) 1104 { 1105 #ifdef INET6 1106 struct ip6_hdr *ip6; 1107 #endif 1108 struct ip *ip; 1109 int setdf; 1110 uint8_t itos, proto; 1111 1112 ip = mtod(*mp, struct ip *); 1113 switch (ip->ip_v) { 1114 #ifdef INET 1115 case IPVERSION: 1116 proto = IPPROTO_IPIP; 1117 /* 1118 * Collect IP_DF state from the inner header 1119 * and honor system-wide control of how to handle it. 1120 */ 1121 switch (V_ip4_ipsec_dfbit) { 1122 case 0: /* clear in outer header */ 1123 case 1: /* set in outer header */ 1124 setdf = V_ip4_ipsec_dfbit; 1125 break; 1126 default:/* propagate to outer header */ 1127 setdf = (ip->ip_off & htons(IP_DF)) != 0; 1128 } 1129 itos = ip->ip_tos; 1130 break; 1131 #endif 1132 #ifdef INET6 1133 case (IPV6_VERSION >> 4): 1134 proto = IPPROTO_IPV6; 1135 ip6 = mtod(*mp, struct ip6_hdr *); 1136 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 1137 setdf = V_ip4_ipsec_dfbit ? 1: 0; 1138 /* scoped address handling */ 1139 in6_clearscope(&ip6->ip6_src); 1140 in6_clearscope(&ip6->ip6_dst); 1141 break; 1142 #endif 1143 default: 1144 return (EAFNOSUPPORT); 1145 } 1146 switch (saidx->dst.sa.sa_family) { 1147 #ifdef INET 1148 case AF_INET: 1149 if (saidx->src.sa.sa_family != AF_INET || 1150 saidx->src.sin.sin_addr.s_addr == INADDR_ANY || 1151 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) 1152 return (EINVAL); 1153 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT); 1154 if (*mp == NULL) 1155 return (ENOBUFS); 1156 ip = mtod(*mp, struct ip *); 1157 ip->ip_v = IPVERSION; 1158 ip->ip_hl = sizeof(struct ip) >> 2; 1159 ip->ip_p = proto; 1160 ip->ip_len = htons((*mp)->m_pkthdr.len); 1161 ip->ip_ttl = V_ip_defttl; 1162 ip->ip_sum = 0; 1163 ip->ip_off = setdf ? htons(IP_DF): 0; 1164 ip->ip_src = saidx->src.sin.sin_addr; 1165 ip->ip_dst = saidx->dst.sin.sin_addr; 1166 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos); 1167 ip_fillid(ip); 1168 break; 1169 #endif /* INET */ 1170 #ifdef INET6 1171 case AF_INET6: 1172 if (saidx->src.sa.sa_family != AF_INET6 || 1173 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) || 1174 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr)) 1175 return (EINVAL); 1176 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT); 1177 if (*mp == NULL) 1178 return (ENOBUFS); 1179 ip6 = mtod(*mp, struct ip6_hdr *); 1180 ip6->ip6_flow = 0; 1181 ip6->ip6_vfc = IPV6_VERSION; 1182 ip6->ip6_hlim = V_ip6_defhlim; 1183 ip6->ip6_nxt = proto; 1184 ip6->ip6_dst = saidx->dst.sin6.sin6_addr; 1185 /* For link-local address embed scope zone id */ 1186 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 1187 ip6->ip6_dst.s6_addr16[1] = 1188 htons(saidx->dst.sin6.sin6_scope_id & 0xffff); 1189 ip6->ip6_src = saidx->src.sin6.sin6_addr; 1190 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 1191 ip6->ip6_src.s6_addr16[1] = 1192 htons(saidx->src.sin6.sin6_scope_id & 0xffff); 1193 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6)); 1194 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos); 1195 ip6->ip6_flow |= htonl((uint32_t)proto << 20); 1196 break; 1197 #endif /* INET6 */ 1198 default: 1199 return (EAFNOSUPPORT); 1200 } 1201 (*mp)->m_flags &= ~(M_BCAST | M_MCAST); 1202 return (0); 1203 } 1204