Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netipsec/ipsec_output.c
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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, 185 struct inpcb *inp, u_int idx) 186 { 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, inp, 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 SPI 0x%08x failed " 234 "with error %d\n", __func__, ntohl(sav->spi), 235 error)); 236 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 237 goto bad; 238 } 239 inp = NULL; 240 } 241 242 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 243 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 244 goto bad; 245 246 /* 247 * Dispatch to the appropriate IPsec transform logic. The 248 * packet will be returned for transmission after crypto 249 * processing, etc. are completed. 250 * 251 * NB: m & sav are ``passed to caller'' who's responsible for 252 * reclaiming their resources. 253 */ 254 switch(dst->sa.sa_family) { 255 case AF_INET: 256 ip = mtod(m, struct ip *); 257 i = ip->ip_hl << 2; 258 off = offsetof(struct ip, ip_p); 259 break; 260 #ifdef INET6 261 case AF_INET6: 262 i = sizeof(struct ip6_hdr); 263 off = offsetof(struct ip6_hdr, ip6_nxt); 264 break; 265 #endif /* INET6 */ 266 default: 267 DPRINTF(("%s: unsupported protocol family %u\n", 268 __func__, dst->sa.sa_family)); 269 error = EPFNOSUPPORT; 270 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 271 goto bad; 272 } 273 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 274 return (error); 275 bad: 276 IPSECSTAT_INC(ips_out_inval); 277 if (m != NULL) 278 m_freem(m); 279 if (sav != NULL) 280 key_freesav(&sav); 281 key_freesp(&sp); 282 return (error); 283 } 284 285 int 286 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp, 287 struct inpcb *inp) 288 { 289 290 return (ipsec4_perform_request(m, sp, inp, 0)); 291 } 292 293 static int 294 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 295 { 296 struct secpolicy *sp; 297 int error; 298 299 /* Lookup for the corresponding outbound security policy */ 300 sp = ipsec4_checkpolicy(m, inp, &error, !forwarding); 301 if (sp == NULL) { 302 if (error == -EINVAL) { 303 /* Discarded by policy. */ 304 m_freem(m); 305 return (EACCES); 306 } 307 return (0); /* No IPsec required. */ 308 } 309 310 /* 311 * Usually we have to have tunnel mode IPsec security policy 312 * when we are forwarding a packet. Otherwise we could not handle 313 * encrypted replies, because they are not destined for us. But 314 * some users are doing source address translation for forwarded 315 * packets, and thus, even if they are forwarded, the replies will 316 * return back to us. 317 */ 318 if (!forwarding) { 319 /* 320 * Do delayed checksums now because we send before 321 * this is done in the normal processing path. 322 */ 323 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 324 in_delayed_cksum(m); 325 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 326 } 327 #ifdef SCTP 328 if (m->m_pkthdr.csum_flags & CSUM_SCTP) { 329 struct ip *ip = mtod(m, struct ip *); 330 331 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 332 m->m_pkthdr.csum_flags &= ~CSUM_SCTP; 333 } 334 #endif 335 } 336 /* NB: callee frees mbuf and releases reference to SP */ 337 error = ipsec4_process_packet(m, sp, inp); 338 if (error == EJUSTRETURN) { 339 /* 340 * We had a SP with a level of 'use' and no SA. We 341 * will just continue to process the packet without 342 * IPsec processing and return without error. 343 */ 344 return (0); 345 } 346 if (error == 0) 347 return (EINPROGRESS); /* consumed by IPsec */ 348 return (error); 349 } 350 351 /* 352 * IPSEC_OUTPUT() method implementation for IPv4. 353 * 0 - no IPsec handling needed 354 * other values - mbuf consumed by IPsec. 355 */ 356 int 357 ipsec4_output(struct mbuf *m, struct inpcb *inp) 358 { 359 360 /* 361 * If the packet is resubmitted to ip_output (e.g. after 362 * AH, ESP, etc. processing), there will be a tag to bypass 363 * the lookup and related policy checking. 364 */ 365 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 366 return (0); 367 368 return (ipsec4_common_output(m, inp, 0)); 369 } 370 371 /* 372 * IPSEC_FORWARD() method implementation for IPv4. 373 * 0 - no IPsec handling needed 374 * other values - mbuf consumed by IPsec. 375 */ 376 int 377 ipsec4_forward(struct mbuf *m) 378 { 379 380 /* 381 * Check if this packet has an active inbound SP and needs to be 382 * dropped instead of forwarded. 383 */ 384 if (ipsec4_in_reject(m, NULL) != 0) { 385 m_freem(m); 386 return (EACCES); 387 } 388 return (ipsec4_common_output(m, NULL, 1)); 389 } 390 #endif 391 392 #ifdef INET6 393 static int 394 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa, 395 const struct in6_addr *ia) 396 { 397 struct in6_addr ia2; 398 399 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) { 400 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2)); 401 ia2.s6_addr16[1] = htons(sa->sin6_scope_id); 402 return (IN6_ARE_ADDR_EQUAL(ia, &ia2)); 403 } 404 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia)); 405 } 406 407 static struct secasvar * 408 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 409 { 410 struct secasindex *saidx, tmpsaidx; 411 struct ipsecrequest *isr; 412 struct sockaddr_in6 *sin6; 413 struct secasvar *sav; 414 struct ip6_hdr *ip6; 415 416 /* 417 * Check system global policy controls. 418 */ 419 next: 420 isr = sp->req[*pidx]; 421 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 422 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 423 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 424 DPRINTF(("%s: IPsec outbound packet dropped due" 425 " to policy (check your sysctls)\n", __func__)); 426 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 427 *error = EHOSTUNREACH; 428 return (NULL); 429 } 430 /* 431 * Craft SA index to search for proper SA. Note that 432 * we only fillin unspecified SA peers for transport 433 * mode; for tunnel mode they must already be filled in. 434 */ 435 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 436 saidx = &tmpsaidx; 437 *saidx = isr->saidx; 438 ip6 = mtod(m, struct ip6_hdr *); 439 if (saidx->src.sin6.sin6_len == 0) { 440 sin6 = (struct sockaddr_in6 *)&saidx->src; 441 sin6->sin6_len = sizeof(*sin6); 442 sin6->sin6_family = AF_INET6; 443 sin6->sin6_port = IPSEC_PORT_ANY; 444 sin6->sin6_addr = ip6->ip6_src; 445 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 446 /* fix scope id for comparing SPD */ 447 sin6->sin6_addr.s6_addr16[1] = 0; 448 sin6->sin6_scope_id = 449 ntohs(ip6->ip6_src.s6_addr16[1]); 450 } 451 } 452 if (saidx->dst.sin6.sin6_len == 0) { 453 sin6 = (struct sockaddr_in6 *)&saidx->dst; 454 sin6->sin6_len = sizeof(*sin6); 455 sin6->sin6_family = AF_INET6; 456 sin6->sin6_port = IPSEC_PORT_ANY; 457 sin6->sin6_addr = ip6->ip6_dst; 458 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 459 /* fix scope id for comparing SPD */ 460 sin6->sin6_addr.s6_addr16[1] = 0; 461 sin6->sin6_scope_id = 462 ntohs(ip6->ip6_dst.s6_addr16[1]); 463 } 464 } 465 } else 466 saidx = &sp->req[*pidx]->saidx; 467 /* 468 * Lookup SA and validate it. 469 */ 470 sav = key_allocsa_policy(sp, saidx, error); 471 if (sav == NULL) { 472 IPSEC6STAT_INC(ips_out_nosa); 473 if (*error != 0) 474 return (NULL); 475 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 476 /* 477 * We have no SA and policy that doesn't require 478 * this IPsec transform, thus we can continue w/o 479 * IPsec processing, i.e. return EJUSTRETURN. 480 * But first check if there is some bundled transform. 481 */ 482 if (sp->tcount > ++(*pidx)) 483 goto next; 484 *error = EJUSTRETURN; 485 } 486 return (NULL); 487 } 488 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 489 return (sav); 490 } 491 492 /* 493 * IPsec output logic for IPv6. 494 */ 495 static int 496 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp, 497 struct inpcb *inp, u_int idx) 498 { 499 struct ipsec_ctx_data ctx; 500 union sockaddr_union *dst; 501 struct secasvar *sav; 502 struct ip6_hdr *ip6; 503 int error, i, off; 504 505 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 506 507 sav = ipsec6_allocsa(m, sp, &idx, &error); 508 if (sav == NULL) { 509 if (error == EJUSTRETURN) { /* No IPsec required */ 510 key_freesp(&sp); 511 return (error); 512 } 513 goto bad; 514 } 515 516 /* Fix IP length in case if it is not set yet. */ 517 ip6 = mtod(m, struct ip6_hdr *); 518 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); 519 520 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE); 521 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 522 goto bad; 523 524 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */ 525 dst = &sav->sah->saidx.dst; 526 527 /* Do the appropriate encapsulation, if necessary */ 528 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 529 dst->sa.sa_family != AF_INET6 || /* PF mismatch */ 530 ((dst->sa.sa_family == AF_INET6) && 531 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) && 532 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) { 533 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) { 534 /* No jumbogram support. */ 535 error = ENXIO; /*XXX*/ 536 goto bad; 537 } 538 error = ipsec_encap(&m, &sav->sah->saidx); 539 if (error != 0) { 540 DPRINTF(("%s: encapsulation for SPI 0x%08x failed " 541 "with error %d\n", __func__, ntohl(sav->spi), 542 error)); 543 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 544 goto bad; 545 } 546 inp = NULL; 547 } 548 549 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 550 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 551 goto bad; 552 553 switch(dst->sa.sa_family) { 554 #ifdef INET 555 case AF_INET: 556 { 557 struct ip *ip; 558 ip = mtod(m, struct ip *); 559 i = ip->ip_hl << 2; 560 off = offsetof(struct ip, ip_p); 561 } 562 break; 563 #endif /* AF_INET */ 564 case AF_INET6: 565 i = sizeof(struct ip6_hdr); 566 off = offsetof(struct ip6_hdr, ip6_nxt); 567 break; 568 default: 569 DPRINTF(("%s: unsupported protocol family %u\n", 570 __func__, dst->sa.sa_family)); 571 error = EPFNOSUPPORT; 572 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 573 goto bad; 574 } 575 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 576 return (error); 577 bad: 578 IPSEC6STAT_INC(ips_out_inval); 579 if (m != NULL) 580 m_freem(m); 581 if (sav != NULL) 582 key_freesav(&sav); 583 key_freesp(&sp); 584 return (error); 585 } 586 587 int 588 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp, 589 struct inpcb *inp) 590 { 591 592 return (ipsec6_perform_request(m, sp, inp, 0)); 593 } 594 595 static int 596 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 597 { 598 struct secpolicy *sp; 599 int error; 600 601 /* Lookup for the corresponding outbound security policy */ 602 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding); 603 if (sp == NULL) { 604 if (error == -EINVAL) { 605 /* Discarded by policy. */ 606 m_freem(m); 607 return (EACCES); 608 } 609 return (0); /* No IPsec required. */ 610 } 611 612 if (!forwarding) { 613 /* 614 * Do delayed checksums now because we send before 615 * this is done in the normal processing path. 616 */ 617 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 618 in6_delayed_cksum(m, m->m_pkthdr.len - 619 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr)); 620 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 621 } 622 #ifdef SCTP 623 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 624 sctp_delayed_cksum(m, sizeof(struct ip6_hdr)); 625 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 626 } 627 #endif 628 } 629 /* NB: callee frees mbuf and releases reference to SP */ 630 error = ipsec6_process_packet(m, sp, inp); 631 if (error == EJUSTRETURN) { 632 /* 633 * We had a SP with a level of 'use' and no SA. We 634 * will just continue to process the packet without 635 * IPsec processing and return without error. 636 */ 637 return (0); 638 } 639 if (error == 0) 640 return (EINPROGRESS); /* consumed by IPsec */ 641 return (error); 642 } 643 644 /* 645 * IPSEC_OUTPUT() method implementation for IPv6. 646 * 0 - no IPsec handling needed 647 * other values - mbuf consumed by IPsec. 648 */ 649 int 650 ipsec6_output(struct mbuf *m, struct inpcb *inp) 651 { 652 653 /* 654 * If the packet is resubmitted to ip_output (e.g. after 655 * AH, ESP, etc. processing), there will be a tag to bypass 656 * the lookup and related policy checking. 657 */ 658 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 659 return (0); 660 661 return (ipsec6_common_output(m, inp, 0)); 662 } 663 664 /* 665 * IPSEC_FORWARD() method implementation for IPv6. 666 * 0 - no IPsec handling needed 667 * other values - mbuf consumed by IPsec. 668 */ 669 int 670 ipsec6_forward(struct mbuf *m) 671 { 672 673 /* 674 * Check if this packet has an active inbound SP and needs to be 675 * dropped instead of forwarded. 676 */ 677 if (ipsec6_in_reject(m, NULL) != 0) { 678 m_freem(m); 679 return (EACCES); 680 } 681 return (ipsec6_common_output(m, NULL, 1)); 682 } 683 #endif /* INET6 */ 684 685 int 686 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 687 u_int idx) 688 { 689 struct xform_history *xh; 690 struct secasindex *saidx; 691 struct m_tag *mtag; 692 int error; 693 694 saidx = &sav->sah->saidx; 695 switch (saidx->dst.sa.sa_family) { 696 #ifdef INET 697 case AF_INET: 698 /* Fix the header length, for AH processing. */ 699 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len); 700 break; 701 #endif /* INET */ 702 #ifdef INET6 703 case AF_INET6: 704 /* Fix the header length, for AH processing. */ 705 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) { 706 error = ENXIO; 707 goto bad; 708 } 709 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) { 710 /* No jumbogram support. */ 711 error = ENXIO; /*?*/ 712 goto bad; 713 } 714 mtod(m, struct ip6_hdr *)->ip6_plen = 715 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); 716 break; 717 #endif /* INET6 */ 718 default: 719 DPRINTF(("%s: unknown protocol family %u\n", __func__, 720 saidx->dst.sa.sa_family)); 721 error = ENXIO; 722 goto bad; 723 } 724 725 /* 726 * Add a record of what we've done to the packet. 727 */ 728 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT); 729 if (mtag == NULL) { 730 DPRINTF(("%s: could not get packet tag\n", __func__)); 731 error = ENOMEM; 732 goto bad; 733 } 734 735 xh = (struct xform_history *)(mtag + 1); 736 xh->dst = saidx->dst; 737 xh->proto = saidx->proto; 738 xh->mode = saidx->mode; 739 xh->spi = sav->spi; 740 m_tag_prepend(m, mtag); 741 742 key_sa_recordxfer(sav, m); /* record data transfer */ 743 744 /* 745 * If there's another (bundled) SA to apply, do so. 746 * Note that this puts a burden on the kernel stack size. 747 * If this is a problem we'll need to introduce a queue 748 * to set the packet on so we can unwind the stack before 749 * doing further processing. 750 */ 751 if (++idx < sp->tcount) { 752 switch (saidx->dst.sa.sa_family) { 753 #ifdef INET 754 case AF_INET: 755 key_freesav(&sav); 756 IPSECSTAT_INC(ips_out_bundlesa); 757 return (ipsec4_perform_request(m, sp, NULL, idx)); 758 /* NOTREACHED */ 759 #endif 760 #ifdef INET6 761 case AF_INET6: 762 key_freesav(&sav); 763 IPSEC6STAT_INC(ips_out_bundlesa); 764 return (ipsec6_perform_request(m, sp, NULL, idx)); 765 /* NOTREACHED */ 766 #endif /* INET6 */ 767 default: 768 DPRINTF(("%s: unknown protocol family %u\n", __func__, 769 saidx->dst.sa.sa_family)); 770 error = EPFNOSUPPORT; 771 goto bad; 772 } 773 } 774 775 key_freesp(&sp), sp = NULL; /* Release reference to SP */ 776 #ifdef INET 777 /* 778 * Do UDP encapsulation if SA requires it. 779 */ 780 if (sav->natt != NULL) { 781 error = udp_ipsec_output(m, sav); 782 if (error != 0) 783 goto bad; 784 } 785 #endif /* INET */ 786 /* 787 * We're done with IPsec processing, transmit the packet using the 788 * appropriate network protocol (IP or IPv6). 789 */ 790 switch (saidx->dst.sa.sa_family) { 791 #ifdef INET 792 case AF_INET: 793 key_freesav(&sav); 794 return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL); 795 #endif /* INET */ 796 #ifdef INET6 797 case AF_INET6: 798 key_freesav(&sav); 799 return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 800 #endif /* INET6 */ 801 } 802 panic("ipsec_process_done"); 803 bad: 804 m_freem(m); 805 key_freesav(&sav); 806 if (sp != NULL) 807 key_freesp(&sp); 808 return (error); 809 } 810 811 /* 812 * ipsec_prepend() is optimized version of M_PREPEND(). 813 * ipsec_encap() is called by IPsec output routine for tunnel mode SA. 814 * It is expected that after IP encapsulation some IPsec transform will 815 * be performed. Each IPsec transform inserts its variable length header 816 * just after outer IP header using m_makespace(). If given mbuf has not 817 * enough free space at the beginning, we allocate new mbuf and reserve 818 * some space at the beginning and at the end. 819 * This helps avoid allocating of new mbuf and data copying in m_makespace(), 820 * we place outer header in the middle of mbuf's data with reserved leading 821 * and trailing space: 822 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ] 823 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will 824 * be used to inject AH/ESP/IPCOMP header. 825 */ 826 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \ 827 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \ 828 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */)) 829 static struct mbuf * 830 ipsec_prepend(struct mbuf *m, int len, int how) 831 { 832 struct mbuf *n; 833 834 M_ASSERTPKTHDR(m); 835 IPSEC_ASSERT(len < MHLEN, ("wrong length")); 836 if (M_LEADINGSPACE(m) >= len) { 837 /* No need to allocate new mbuf. */ 838 m->m_data -= len; 839 m->m_len += len; 840 m->m_pkthdr.len += len; 841 return (m); 842 } 843 n = m_gethdr(how, m->m_type); 844 if (n == NULL) { 845 m_freem(m); 846 return (NULL); 847 } 848 m_move_pkthdr(n, m); 849 n->m_next = m; 850 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n)) 851 m_align(n, len + IPSEC_TRAILINGSPACE); 852 n->m_len = len; 853 n->m_pkthdr.len += len; 854 return (n); 855 } 856 857 static int 858 ipsec_encap(struct mbuf **mp, struct secasindex *saidx) 859 { 860 #ifdef INET6 861 struct ip6_hdr *ip6; 862 #endif 863 struct ip *ip; 864 int setdf; 865 uint8_t itos, proto; 866 867 ip = mtod(*mp, struct ip *); 868 switch (ip->ip_v) { 869 #ifdef INET 870 case IPVERSION: 871 proto = IPPROTO_IPIP; 872 /* 873 * Collect IP_DF state from the inner header 874 * and honor system-wide control of how to handle it. 875 */ 876 switch (V_ip4_ipsec_dfbit) { 877 case 0: /* clear in outer header */ 878 case 1: /* set in outer header */ 879 setdf = V_ip4_ipsec_dfbit; 880 break; 881 default:/* propagate to outer header */ 882 setdf = (ip->ip_off & htons(IP_DF)) != 0; 883 } 884 itos = ip->ip_tos; 885 break; 886 #endif 887 #ifdef INET6 888 case (IPV6_VERSION >> 4): 889 proto = IPPROTO_IPV6; 890 ip6 = mtod(*mp, struct ip6_hdr *); 891 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 892 setdf = V_ip4_ipsec_dfbit ? 1: 0; 893 /* scoped address handling */ 894 in6_clearscope(&ip6->ip6_src); 895 in6_clearscope(&ip6->ip6_dst); 896 break; 897 #endif 898 default: 899 return (EAFNOSUPPORT); 900 } 901 switch (saidx->dst.sa.sa_family) { 902 #ifdef INET 903 case AF_INET: 904 if (saidx->src.sa.sa_family != AF_INET || 905 saidx->src.sin.sin_addr.s_addr == INADDR_ANY || 906 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) 907 return (EINVAL); 908 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT); 909 if (*mp == NULL) 910 return (ENOBUFS); 911 ip = mtod(*mp, struct ip *); 912 ip->ip_v = IPVERSION; 913 ip->ip_hl = sizeof(struct ip) >> 2; 914 ip->ip_p = proto; 915 ip->ip_len = htons((*mp)->m_pkthdr.len); 916 ip->ip_ttl = V_ip_defttl; 917 ip->ip_sum = 0; 918 ip->ip_off = setdf ? htons(IP_DF): 0; 919 ip->ip_src = saidx->src.sin.sin_addr; 920 ip->ip_dst = saidx->dst.sin.sin_addr; 921 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos); 922 ip_fillid(ip); 923 break; 924 #endif /* INET */ 925 #ifdef INET6 926 case AF_INET6: 927 if (saidx->src.sa.sa_family != AF_INET6 || 928 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) || 929 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr)) 930 return (EINVAL); 931 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT); 932 if (*mp == NULL) 933 return (ENOBUFS); 934 ip6 = mtod(*mp, struct ip6_hdr *); 935 ip6->ip6_flow = 0; 936 ip6->ip6_vfc = IPV6_VERSION; 937 ip6->ip6_hlim = V_ip6_defhlim; 938 ip6->ip6_nxt = proto; 939 ip6->ip6_dst = saidx->dst.sin6.sin6_addr; 940 /* For link-local address embed scope zone id */ 941 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 942 ip6->ip6_dst.s6_addr16[1] = 943 htons(saidx->dst.sin6.sin6_scope_id & 0xffff); 944 ip6->ip6_src = saidx->src.sin6.sin6_addr; 945 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 946 ip6->ip6_src.s6_addr16[1] = 947 htons(saidx->src.sin6.sin6_scope_id & 0xffff); 948 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6)); 949 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos); 950 ip6->ip6_flow |= htonl((uint32_t)proto << 20); 951 break; 952 #endif /* INET6 */ 953 default: 954 return (EAFNOSUPPORT); 955 } 956 (*mp)->m_flags &= ~(M_BCAST | M_MCAST); 957 return (0); 958 } 959
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