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