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 if (error != 0) { 277 key_freesav(&sav); 278 key_freesp(&sp); 279 } 280 return (error); 281 bad: 282 IPSECSTAT_INC(ips_out_inval); 283 if (m != NULL) 284 m_freem(m); 285 if (sav != NULL) 286 key_freesav(&sav); 287 key_freesp(&sp); 288 return (error); 289 } 290 291 int 292 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp, 293 struct inpcb *inp) 294 { 295 296 return (ipsec4_perform_request(m, sp, 0)); 297 } 298 299 static int 300 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 301 { 302 struct secpolicy *sp; 303 int error; 304 305 /* Lookup for the corresponding outbound security policy */ 306 sp = ipsec4_checkpolicy(m, inp, &error); 307 if (sp == NULL) { 308 if (error == -EINVAL) { 309 /* Discarded by policy. */ 310 m_freem(m); 311 return (EACCES); 312 } 313 return (0); /* No IPsec required. */ 314 } 315 316 /* 317 * Usually we have to have tunnel mode IPsec security policy 318 * when we are forwarding a packet. Otherwise we could not handle 319 * encrypted replies, because they are not destined for us. But 320 * some users are doing source address translation for forwarded 321 * packets, and thus, even if they are forwarded, the replies will 322 * return back to us. 323 */ 324 if (!forwarding) { 325 /* 326 * Do delayed checksums now because we send before 327 * this is done in the normal processing path. 328 */ 329 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 330 in_delayed_cksum(m); 331 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 332 } 333 #ifdef SCTP 334 if (m->m_pkthdr.csum_flags & CSUM_SCTP) { 335 struct ip *ip = mtod(m, struct ip *); 336 337 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 338 m->m_pkthdr.csum_flags &= ~CSUM_SCTP; 339 } 340 #endif 341 } 342 /* NB: callee frees mbuf and releases reference to SP */ 343 error = ipsec4_process_packet(m, sp, inp); 344 if (error == EJUSTRETURN) { 345 /* 346 * We had a SP with a level of 'use' and no SA. We 347 * will just continue to process the packet without 348 * IPsec processing and return without error. 349 */ 350 return (0); 351 } 352 if (error == 0) 353 return (EINPROGRESS); /* consumed by IPsec */ 354 return (error); 355 } 356 357 /* 358 * IPSEC_OUTPUT() method implementation for IPv4. 359 * 0 - no IPsec handling needed 360 * other values - mbuf consumed by IPsec. 361 */ 362 int 363 ipsec4_output(struct mbuf *m, struct inpcb *inp) 364 { 365 366 /* 367 * If the packet is resubmitted to ip_output (e.g. after 368 * AH, ESP, etc. processing), there will be a tag to bypass 369 * the lookup and related policy checking. 370 */ 371 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 372 return (0); 373 374 return (ipsec4_common_output(m, inp, 0)); 375 } 376 377 /* 378 * IPSEC_FORWARD() method implementation for IPv4. 379 * 0 - no IPsec handling needed 380 * other values - mbuf consumed by IPsec. 381 */ 382 int 383 ipsec4_forward(struct mbuf *m) 384 { 385 386 /* 387 * Check if this packet has an active inbound SP and needs to be 388 * dropped instead of forwarded. 389 */ 390 if (ipsec4_in_reject(m, NULL) != 0) { 391 m_freem(m); 392 return (EACCES); 393 } 394 return (ipsec4_common_output(m, NULL, 1)); 395 } 396 #endif 397 398 #ifdef INET6 399 static int 400 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa, 401 const struct in6_addr *ia) 402 { 403 struct in6_addr ia2; 404 405 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) { 406 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2)); 407 ia2.s6_addr16[1] = htons(sa->sin6_scope_id); 408 return (IN6_ARE_ADDR_EQUAL(ia, &ia2)); 409 } 410 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia)); 411 } 412 413 static struct secasvar * 414 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 415 { 416 struct secasindex *saidx, tmpsaidx; 417 struct ipsecrequest *isr; 418 struct sockaddr_in6 *sin6; 419 struct secasvar *sav; 420 struct ip6_hdr *ip6; 421 422 /* 423 * Check system global policy controls. 424 */ 425 next: 426 isr = sp->req[*pidx]; 427 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 428 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 429 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 430 DPRINTF(("%s: IPsec outbound packet dropped due" 431 " to policy (check your sysctls)\n", __func__)); 432 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 433 *error = EHOSTUNREACH; 434 return (NULL); 435 } 436 /* 437 * Craft SA index to search for proper SA. Note that 438 * we only fillin unspecified SA peers for transport 439 * mode; for tunnel mode they must already be filled in. 440 */ 441 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 442 saidx = &tmpsaidx; 443 *saidx = isr->saidx; 444 ip6 = mtod(m, struct ip6_hdr *); 445 if (saidx->src.sin6.sin6_len == 0) { 446 sin6 = (struct sockaddr_in6 *)&saidx->src; 447 sin6->sin6_len = sizeof(*sin6); 448 sin6->sin6_family = AF_INET6; 449 sin6->sin6_port = IPSEC_PORT_ANY; 450 sin6->sin6_addr = ip6->ip6_src; 451 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 452 /* fix scope id for comparing SPD */ 453 sin6->sin6_addr.s6_addr16[1] = 0; 454 sin6->sin6_scope_id = 455 ntohs(ip6->ip6_src.s6_addr16[1]); 456 } 457 } 458 if (saidx->dst.sin6.sin6_len == 0) { 459 sin6 = (struct sockaddr_in6 *)&saidx->dst; 460 sin6->sin6_len = sizeof(*sin6); 461 sin6->sin6_family = AF_INET6; 462 sin6->sin6_port = IPSEC_PORT_ANY; 463 sin6->sin6_addr = ip6->ip6_dst; 464 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 465 /* fix scope id for comparing SPD */ 466 sin6->sin6_addr.s6_addr16[1] = 0; 467 sin6->sin6_scope_id = 468 ntohs(ip6->ip6_dst.s6_addr16[1]); 469 } 470 } 471 } else 472 saidx = &sp->req[*pidx]->saidx; 473 /* 474 * Lookup SA and validate it. 475 */ 476 sav = key_allocsa_policy(sp, saidx, error); 477 if (sav == NULL) { 478 IPSEC6STAT_INC(ips_out_nosa); 479 if (*error != 0) 480 return (NULL); 481 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 482 /* 483 * We have no SA and policy that doesn't require 484 * this IPsec transform, thus we can continue w/o 485 * IPsec processing, i.e. return EJUSTRETURN. 486 * But first check if there is some bundled transform. 487 */ 488 if (sp->tcount > ++(*pidx)) 489 goto next; 490 *error = EJUSTRETURN; 491 } 492 return (NULL); 493 } 494 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 495 return (sav); 496 } 497 498 /* 499 * IPsec output logic for IPv6. 500 */ 501 static int 502 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp, u_int idx) 503 { 504 char sbuf[IPSEC_ADDRSTRLEN], dbuf[IPSEC_ADDRSTRLEN]; 505 struct ipsec_ctx_data ctx; 506 union sockaddr_union *dst; 507 struct secasvar *sav; 508 struct ip6_hdr *ip6; 509 int error, i, off; 510 511 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 512 513 sav = ipsec6_allocsa(m, sp, &idx, &error); 514 if (sav == NULL) { 515 if (error == EJUSTRETURN) { /* No IPsec required */ 516 key_freesp(&sp); 517 return (error); 518 } 519 goto bad; 520 } 521 522 /* Fix IP length in case if it is not set yet. */ 523 ip6 = mtod(m, struct ip6_hdr *); 524 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); 525 526 IPSEC_INIT_CTX(&ctx, &m, sav, AF_INET6, IPSEC_ENC_BEFORE); 527 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 528 goto bad; 529 530 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */ 531 dst = &sav->sah->saidx.dst; 532 533 /* Do the appropriate encapsulation, if necessary */ 534 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 535 dst->sa.sa_family != AF_INET6 || /* PF mismatch */ 536 ((dst->sa.sa_family == AF_INET6) && 537 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) && 538 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) { 539 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) { 540 /* No jumbogram support. */ 541 error = ENXIO; /*XXX*/ 542 goto bad; 543 } 544 error = ipsec_encap(&m, &sav->sah->saidx); 545 if (error != 0) { 546 DPRINTF(("%s: encapsulation for SA %s->%s " 547 "SPI 0x%08x failed with error %d\n", __func__, 548 ipsec_address(&sav->sah->saidx.src, sbuf, 549 sizeof(sbuf)), 550 ipsec_address(&sav->sah->saidx.dst, dbuf, 551 sizeof(dbuf)), ntohl(sav->spi), error)); 552 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 553 goto bad; 554 } 555 } 556 557 IPSEC_INIT_CTX(&ctx, &m, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 558 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 559 goto bad; 560 561 switch(dst->sa.sa_family) { 562 #ifdef INET 563 case AF_INET: 564 { 565 struct ip *ip; 566 ip = mtod(m, struct ip *); 567 i = ip->ip_hl << 2; 568 off = offsetof(struct ip, ip_p); 569 } 570 break; 571 #endif /* AF_INET */ 572 case AF_INET6: 573 i = sizeof(struct ip6_hdr); 574 off = offsetof(struct ip6_hdr, ip6_nxt); 575 break; 576 default: 577 DPRINTF(("%s: unsupported protocol family %u\n", 578 __func__, dst->sa.sa_family)); 579 error = EPFNOSUPPORT; 580 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 581 goto bad; 582 } 583 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 584 if (error != 0) { 585 key_freesav(&sav); 586 key_freesp(&sp); 587 } 588 return (error); 589 bad: 590 IPSEC6STAT_INC(ips_out_inval); 591 if (m != NULL) 592 m_freem(m); 593 if (sav != NULL) 594 key_freesav(&sav); 595 key_freesp(&sp); 596 return (error); 597 } 598 599 int 600 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp, 601 struct inpcb *inp) 602 { 603 604 return (ipsec6_perform_request(m, sp, 0)); 605 } 606 607 static int 608 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 609 { 610 struct secpolicy *sp; 611 int error; 612 613 /* Lookup for the corresponding outbound security policy */ 614 sp = ipsec6_checkpolicy(m, inp, &error); 615 if (sp == NULL) { 616 if (error == -EINVAL) { 617 /* Discarded by policy. */ 618 m_freem(m); 619 return (EACCES); 620 } 621 return (0); /* No IPsec required. */ 622 } 623 624 if (!forwarding) { 625 /* 626 * Do delayed checksums now because we send before 627 * this is done in the normal processing path. 628 */ 629 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 630 in6_delayed_cksum(m, m->m_pkthdr.len - 631 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr)); 632 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 633 } 634 #ifdef SCTP 635 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 636 sctp_delayed_cksum(m, sizeof(struct ip6_hdr)); 637 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 638 } 639 #endif 640 } 641 /* NB: callee frees mbuf and releases reference to SP */ 642 error = ipsec6_process_packet(m, sp, inp); 643 if (error == EJUSTRETURN) { 644 /* 645 * We had a SP with a level of 'use' and no SA. We 646 * will just continue to process the packet without 647 * IPsec processing and return without error. 648 */ 649 return (0); 650 } 651 if (error == 0) 652 return (EINPROGRESS); /* consumed by IPsec */ 653 return (error); 654 } 655 656 /* 657 * IPSEC_OUTPUT() method implementation for IPv6. 658 * 0 - no IPsec handling needed 659 * other values - mbuf consumed by IPsec. 660 */ 661 int 662 ipsec6_output(struct mbuf *m, struct inpcb *inp) 663 { 664 665 /* 666 * If the packet is resubmitted to ip_output (e.g. after 667 * AH, ESP, etc. processing), there will be a tag to bypass 668 * the lookup and related policy checking. 669 */ 670 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 671 return (0); 672 673 return (ipsec6_common_output(m, inp, 0)); 674 } 675 676 /* 677 * IPSEC_FORWARD() method implementation for IPv6. 678 * 0 - no IPsec handling needed 679 * other values - mbuf consumed by IPsec. 680 */ 681 int 682 ipsec6_forward(struct mbuf *m) 683 { 684 685 /* 686 * Check if this packet has an active inbound SP and needs to be 687 * dropped instead of forwarded. 688 */ 689 if (ipsec6_in_reject(m, NULL) != 0) { 690 m_freem(m); 691 return (EACCES); 692 } 693 return (ipsec6_common_output(m, NULL, 1)); 694 } 695 #endif /* INET6 */ 696 697 int 698 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 699 u_int idx) 700 { 701 struct xform_history *xh; 702 struct secasindex *saidx; 703 struct m_tag *mtag; 704 int error; 705 706 saidx = &sav->sah->saidx; 707 switch (saidx->dst.sa.sa_family) { 708 #ifdef INET 709 case AF_INET: 710 /* Fix the header length, for AH processing. */ 711 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len); 712 break; 713 #endif /* INET */ 714 #ifdef INET6 715 case AF_INET6: 716 /* Fix the header length, for AH processing. */ 717 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) { 718 error = ENXIO; 719 goto bad; 720 } 721 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) { 722 /* No jumbogram support. */ 723 error = ENXIO; /*?*/ 724 goto bad; 725 } 726 mtod(m, struct ip6_hdr *)->ip6_plen = 727 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); 728 break; 729 #endif /* INET6 */ 730 default: 731 DPRINTF(("%s: unknown protocol family %u\n", __func__, 732 saidx->dst.sa.sa_family)); 733 error = ENXIO; 734 goto bad; 735 } 736 737 /* 738 * Add a record of what we've done to the packet. 739 */ 740 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT); 741 if (mtag == NULL) { 742 DPRINTF(("%s: could not get packet tag\n", __func__)); 743 error = ENOMEM; 744 goto bad; 745 } 746 747 xh = (struct xform_history *)(mtag + 1); 748 xh->dst = saidx->dst; 749 xh->proto = saidx->proto; 750 xh->mode = saidx->mode; 751 xh->spi = sav->spi; 752 m_tag_prepend(m, mtag); 753 754 key_sa_recordxfer(sav, m); /* record data transfer */ 755 756 /* 757 * If there's another (bundled) SA to apply, do so. 758 * Note that this puts a burden on the kernel stack size. 759 * If this is a problem we'll need to introduce a queue 760 * to set the packet on so we can unwind the stack before 761 * doing further processing. 762 */ 763 if (++idx < sp->tcount) { 764 switch (saidx->dst.sa.sa_family) { 765 #ifdef INET 766 case AF_INET: 767 key_freesav(&sav); 768 IPSECSTAT_INC(ips_out_bundlesa); 769 return (ipsec4_perform_request(m, sp, idx)); 770 /* NOTREACHED */ 771 #endif 772 #ifdef INET6 773 case AF_INET6: 774 key_freesav(&sav); 775 IPSEC6STAT_INC(ips_out_bundlesa); 776 return (ipsec6_perform_request(m, sp, idx)); 777 /* NOTREACHED */ 778 #endif /* INET6 */ 779 default: 780 DPRINTF(("%s: unknown protocol family %u\n", __func__, 781 saidx->dst.sa.sa_family)); 782 error = EPFNOSUPPORT; 783 goto bad; 784 } 785 } 786 787 key_freesp(&sp), sp = NULL; /* Release reference to SP */ 788 #ifdef INET 789 /* 790 * Do UDP encapsulation if SA requires it. 791 */ 792 if (sav->natt != NULL) { 793 error = udp_ipsec_output(m, sav); 794 if (error != 0) 795 goto bad; 796 } 797 #endif /* INET */ 798 /* 799 * We're done with IPsec processing, transmit the packet using the 800 * appropriate network protocol (IP or IPv6). 801 */ 802 switch (saidx->dst.sa.sa_family) { 803 #ifdef INET 804 case AF_INET: 805 key_freesav(&sav); 806 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL); 807 #endif /* INET */ 808 #ifdef INET6 809 case AF_INET6: 810 key_freesav(&sav); 811 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 812 #endif /* INET6 */ 813 } 814 panic("ipsec_process_done"); 815 bad: 816 m_freem(m); 817 key_freesav(&sav); 818 if (sp != NULL) 819 key_freesp(&sp); 820 return (error); 821 } 822 823 /* 824 * ipsec_prepend() is optimized version of M_PREPEND(). 825 * ipsec_encap() is called by IPsec output routine for tunnel mode SA. 826 * It is expected that after IP encapsulation some IPsec transform will 827 * be performed. Each IPsec transform inserts its variable length header 828 * just after outer IP header using m_makespace(). If given mbuf has not 829 * enough free space at the beginning, we allocate new mbuf and reserve 830 * some space at the beginning and at the end. 831 * This helps avoid allocating of new mbuf and data copying in m_makespace(), 832 * we place outer header in the middle of mbuf's data with reserved leading 833 * and trailing space: 834 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ] 835 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will 836 * be used to inject AH/ESP/IPCOMP header. 837 */ 838 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \ 839 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \ 840 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */)) 841 static struct mbuf * 842 ipsec_prepend(struct mbuf *m, int len, int how) 843 { 844 struct mbuf *n; 845 846 M_ASSERTPKTHDR(m); 847 IPSEC_ASSERT(len < MHLEN, ("wrong length")); 848 if (M_LEADINGSPACE(m) >= len) { 849 /* No need to allocate new mbuf. */ 850 m->m_data -= len; 851 m->m_len += len; 852 m->m_pkthdr.len += len; 853 return (m); 854 } 855 n = m_gethdr(how, m->m_type); 856 if (n == NULL) { 857 m_freem(m); 858 return (NULL); 859 } 860 m_move_pkthdr(n, m); 861 n->m_next = m; 862 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n)) 863 m_align(n, len + IPSEC_TRAILINGSPACE); 864 n->m_len = len; 865 n->m_pkthdr.len += len; 866 return (n); 867 } 868 869 static int 870 ipsec_encap(struct mbuf **mp, struct secasindex *saidx) 871 { 872 #ifdef INET6 873 struct ip6_hdr *ip6; 874 #endif 875 struct ip *ip; 876 int setdf; 877 uint8_t itos, proto; 878 879 ip = mtod(*mp, struct ip *); 880 switch (ip->ip_v) { 881 #ifdef INET 882 case IPVERSION: 883 proto = IPPROTO_IPIP; 884 /* 885 * Collect IP_DF state from the inner header 886 * and honor system-wide control of how to handle it. 887 */ 888 switch (V_ip4_ipsec_dfbit) { 889 case 0: /* clear in outer header */ 890 case 1: /* set in outer header */ 891 setdf = V_ip4_ipsec_dfbit; 892 break; 893 default:/* propagate to outer header */ 894 setdf = (ip->ip_off & htons(IP_DF)) != 0; 895 } 896 itos = ip->ip_tos; 897 break; 898 #endif 899 #ifdef INET6 900 case (IPV6_VERSION >> 4): 901 proto = IPPROTO_IPV6; 902 ip6 = mtod(*mp, struct ip6_hdr *); 903 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 904 setdf = V_ip4_ipsec_dfbit ? 1: 0; 905 /* scoped address handling */ 906 in6_clearscope(&ip6->ip6_src); 907 in6_clearscope(&ip6->ip6_dst); 908 break; 909 #endif 910 default: 911 return (EAFNOSUPPORT); 912 } 913 switch (saidx->dst.sa.sa_family) { 914 #ifdef INET 915 case AF_INET: 916 if (saidx->src.sa.sa_family != AF_INET || 917 saidx->src.sin.sin_addr.s_addr == INADDR_ANY || 918 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) 919 return (EINVAL); 920 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT); 921 if (*mp == NULL) 922 return (ENOBUFS); 923 ip = mtod(*mp, struct ip *); 924 ip->ip_v = IPVERSION; 925 ip->ip_hl = sizeof(struct ip) >> 2; 926 ip->ip_p = proto; 927 ip->ip_len = htons((*mp)->m_pkthdr.len); 928 ip->ip_ttl = V_ip_defttl; 929 ip->ip_sum = 0; 930 ip->ip_off = setdf ? htons(IP_DF): 0; 931 ip->ip_src = saidx->src.sin.sin_addr; 932 ip->ip_dst = saidx->dst.sin.sin_addr; 933 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos); 934 ip_fillid(ip); 935 break; 936 #endif /* INET */ 937 #ifdef INET6 938 case AF_INET6: 939 if (saidx->src.sa.sa_family != AF_INET6 || 940 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) || 941 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr)) 942 return (EINVAL); 943 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT); 944 if (*mp == NULL) 945 return (ENOBUFS); 946 ip6 = mtod(*mp, struct ip6_hdr *); 947 ip6->ip6_flow = 0; 948 ip6->ip6_vfc = IPV6_VERSION; 949 ip6->ip6_hlim = V_ip6_defhlim; 950 ip6->ip6_nxt = proto; 951 ip6->ip6_dst = saidx->dst.sin6.sin6_addr; 952 /* For link-local address embed scope zone id */ 953 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 954 ip6->ip6_dst.s6_addr16[1] = 955 htons(saidx->dst.sin6.sin6_scope_id & 0xffff); 956 ip6->ip6_src = saidx->src.sin6.sin6_addr; 957 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 958 ip6->ip6_src.s6_addr16[1] = 959 htons(saidx->src.sin6.sin6_scope_id & 0xffff); 960 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6)); 961 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos); 962 ip6->ip6_flow |= htonl((uint32_t)proto << 20); 963 break; 964 #endif /* INET6 */ 965 default: 966 return (EAFNOSUPPORT); 967 } 968 (*mp)->m_flags &= ~(M_BCAST | M_MCAST); 969 return (0); 970 } 971 972