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sys/netipsec/ipsec_output.c
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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_pcb.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/ip.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip_ecn.h> 62 #ifdef INET6 63 #include <netinet6/ip6_ecn.h> 64 #endif 65 #include <netinet/ip_icmp.h> 66 #include <netinet/tcp_var.h> 67 68 #include <netinet/ip6.h> 69 #ifdef INET6 70 #include <netinet6/ip6_var.h> 71 #include <netinet6/scope6_var.h> 72 #endif 73 #include <netinet/in_pcb.h> 74 #ifdef INET6 75 #include <netinet/icmp6.h> 76 #endif 77 #if defined(SCTP) || defined(SCTP_SUPPORT) 78 #include <netinet/sctp_crc32.h> 79 #endif 80 81 #include <netinet/udp.h> 82 #include <netipsec/ah.h> 83 #include <netipsec/esp.h> 84 #include <netipsec/ipsec.h> 85 #ifdef INET6 86 #include <netipsec/ipsec6.h> 87 #endif 88 #include <netipsec/ipsec_support.h> 89 #include <netipsec/ah_var.h> 90 #include <netipsec/esp_var.h> 91 #include <netipsec/ipcomp_var.h> 92 93 #include <netipsec/xform.h> 94 95 #include <netipsec/key.h> 96 #include <netipsec/keydb.h> 97 #include <netipsec/key_debug.h> 98 99 #include <machine/in_cksum.h> 100 101 #define IPSEC_OSTAT_INC(proto, name) do { \ 102 if ((proto) == IPPROTO_ESP) \ 103 ESPSTAT_INC(esps_##name); \ 104 else if ((proto) == IPPROTO_AH)\ 105 AHSTAT_INC(ahs_##name); \ 106 else \ 107 IPCOMPSTAT_INC(ipcomps_##name); \ 108 } while (0) 109 110 static int ipsec_encap(struct mbuf **mp, struct secasindex *saidx); 111 static size_t ipsec_get_pmtu(struct secasvar *sav); 112 113 #ifdef INET 114 static struct secasvar * 115 ipsec4_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 116 { 117 struct secasindex *saidx, tmpsaidx; 118 struct ipsecrequest *isr; 119 struct sockaddr_in *sin; 120 struct secasvar *sav; 121 struct ip *ip; 122 123 /* 124 * Check system global policy controls. 125 */ 126 next: 127 isr = sp->req[*pidx]; 128 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 129 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 130 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 131 DPRINTF(("%s: IPsec outbound packet dropped due" 132 " to policy (check your sysctls)\n", __func__)); 133 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 134 *error = EHOSTUNREACH; 135 return (NULL); 136 } 137 /* 138 * Craft SA index to search for proper SA. Note that 139 * we only initialize unspecified SA peers for transport 140 * mode; for tunnel mode they must already be filled in. 141 */ 142 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 143 saidx = &tmpsaidx; 144 *saidx = isr->saidx; 145 ip = mtod(m, struct ip *); 146 if (saidx->src.sa.sa_len == 0) { 147 sin = &saidx->src.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_src; 152 } 153 if (saidx->dst.sa.sa_len == 0) { 154 sin = &saidx->dst.sin; 155 sin->sin_len = sizeof(*sin); 156 sin->sin_family = AF_INET; 157 sin->sin_port = IPSEC_PORT_ANY; 158 sin->sin_addr = ip->ip_dst; 159 } 160 } else 161 saidx = &sp->req[*pidx]->saidx; 162 /* 163 * Lookup SA and validate it. 164 */ 165 sav = key_allocsa_policy(sp, saidx, error); 166 if (sav == NULL) { 167 IPSECSTAT_INC(ips_out_nosa); 168 if (*error != 0) 169 return (NULL); 170 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 171 /* 172 * We have no SA and policy that doesn't require 173 * this IPsec transform, thus we can continue w/o 174 * IPsec processing, i.e. return EJUSTRETURN. 175 * But first check if there is some bundled transform. 176 */ 177 if (sp->tcount > ++(*pidx)) 178 goto next; 179 *error = EJUSTRETURN; 180 } 181 return (NULL); 182 } 183 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 184 return (sav); 185 } 186 187 /* 188 * IPsec output logic for IPv4. 189 */ 190 static int 191 ipsec4_perform_request(struct mbuf *m, struct secpolicy *sp, 192 struct inpcb *inp, u_int idx) 193 { 194 struct ipsec_ctx_data ctx; 195 union sockaddr_union *dst; 196 struct secasvar *sav; 197 struct ip *ip; 198 int error, i, off; 199 200 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 201 202 /* 203 * We hold the reference to SP. Content of SP couldn't be changed. 204 * Craft secasindex and do lookup for suitable SA. 205 * Then do encapsulation if needed and call xform's output. 206 * We need to store SP in the xform callback parameters. 207 * In xform callback we will extract SP and it can be used to 208 * determine next transform. At the end of transform we can 209 * release reference to SP. 210 */ 211 sav = ipsec4_allocsa(m, sp, &idx, &error); 212 if (sav == NULL) { 213 if (error == EJUSTRETURN) { /* No IPsec required */ 214 key_freesp(&sp); 215 return (error); 216 } 217 goto bad; 218 } 219 /* 220 * XXXAE: most likely ip_sum at this point is wrong. 221 */ 222 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET, IPSEC_ENC_BEFORE); 223 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 224 goto bad; 225 226 ip = mtod(m, struct ip *); 227 dst = &sav->sah->saidx.dst; 228 /* Do the appropriate encapsulation, if necessary */ 229 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 230 dst->sa.sa_family != AF_INET || /* PF mismatch */ 231 (dst->sa.sa_family == AF_INET && /* Proxy */ 232 dst->sin.sin_addr.s_addr != INADDR_ANY && 233 dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) { 234 /* Fix IPv4 header checksum and length */ 235 ip->ip_len = htons(m->m_pkthdr.len); 236 ip->ip_sum = 0; 237 ip->ip_sum = in_cksum(m, ip->ip_hl << 2); 238 error = ipsec_encap(&m, &sav->sah->saidx); 239 if (error != 0) { 240 DPRINTF(("%s: encapsulation for SPI 0x%08x failed " 241 "with error %d\n", __func__, ntohl(sav->spi), 242 error)); 243 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 244 goto bad; 245 } 246 inp = NULL; 247 } 248 249 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 250 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 251 goto bad; 252 253 /* 254 * Dispatch to the appropriate IPsec transform logic. The 255 * packet will be returned for transmission after crypto 256 * processing, etc. are completed. 257 * 258 * NB: m & sav are ``passed to caller'' who's responsible for 259 * reclaiming their resources. 260 */ 261 switch(dst->sa.sa_family) { 262 case AF_INET: 263 ip = mtod(m, struct ip *); 264 i = ip->ip_hl << 2; 265 off = offsetof(struct ip, ip_p); 266 break; 267 #ifdef INET6 268 case AF_INET6: 269 i = sizeof(struct ip6_hdr); 270 off = offsetof(struct ip6_hdr, ip6_nxt); 271 break; 272 #endif /* INET6 */ 273 default: 274 DPRINTF(("%s: unsupported protocol family %u\n", 275 __func__, dst->sa.sa_family)); 276 error = EPFNOSUPPORT; 277 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 278 goto bad; 279 } 280 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 281 return (error); 282 bad: 283 IPSECSTAT_INC(ips_out_inval); 284 if (m != NULL) 285 m_freem(m); 286 if (sav != NULL) 287 key_freesav(&sav); 288 key_freesp(&sp); 289 return (error); 290 } 291 292 int 293 ipsec4_process_packet(struct mbuf *m, struct secpolicy *sp, 294 struct inpcb *inp) 295 { 296 297 return (ipsec4_perform_request(m, sp, inp, 0)); 298 } 299 300 int 301 ipsec4_check_pmtu(struct mbuf *m, struct secpolicy *sp, int forwarding) 302 { 303 struct secasvar *sav; 304 struct ip *ip; 305 size_t hlen, pmtu; 306 uint32_t idx; 307 int error; 308 309 /* Don't check PMTU if the frame won't have DF bit set. */ 310 if (!V_ip4_ipsec_dfbit) 311 return (0); 312 if (V_ip4_ipsec_dfbit == 1) 313 goto setdf; 314 315 /* V_ip4_ipsec_dfbit > 1 - we will copy it from inner header. */ 316 ip = mtod(m, struct ip *); 317 if (!(ip->ip_off & htons(IP_DF))) 318 return (0); 319 320 setdf: 321 idx = sp->tcount - 1; 322 sav = ipsec4_allocsa(m, sp, &idx, &error); 323 if (sav == NULL) { 324 key_freesp(&sp); 325 /* 326 * No matching SA was found and SADB_ACQUIRE message was generated. 327 * Since we have matched a SP to this packet drop it silently. 328 */ 329 if (error == 0) 330 error = EINPROGRESS; 331 if (error != EJUSTRETURN) 332 m_freem(m); 333 334 return (error); 335 } 336 337 pmtu = ipsec_get_pmtu(sav); 338 if (pmtu == 0) { 339 key_freesav(&sav); 340 return (0); 341 } 342 343 hlen = ipsec_hdrsiz_internal(sp); 344 key_freesav(&sav); 345 346 if (m_length(m, NULL) + hlen > pmtu) { 347 /* 348 * If we're forwarding generate ICMP message here, 349 * so that it contains pmtu subtracted by header size. 350 * Set error to EINPROGRESS, in order for the frame 351 * to be dropped silently. 352 */ 353 if (forwarding) { 354 if (pmtu > hlen) 355 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 356 0, pmtu - hlen); 357 else 358 m_freem(m); 359 360 key_freesp(&sp); 361 return (EINPROGRESS); /* Pretend that we consumed it. */ 362 } else { 363 m_freem(m); 364 key_freesp(&sp); 365 return (EMSGSIZE); 366 } 367 } 368 369 return (0); 370 } 371 372 static int 373 ipsec4_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 374 { 375 struct secpolicy *sp; 376 int error; 377 378 /* Lookup for the corresponding outbound security policy */ 379 sp = ipsec4_checkpolicy(m, inp, &error, !forwarding); 380 if (sp == NULL) { 381 if (error == -EINVAL) { 382 /* Discarded by policy. */ 383 m_freem(m); 384 return (EACCES); 385 } 386 return (0); /* No IPsec required. */ 387 } 388 389 /* 390 * Usually we have to have tunnel mode IPsec security policy 391 * when we are forwarding a packet. Otherwise we could not handle 392 * encrypted replies, because they are not destined for us. But 393 * some users are doing source address translation for forwarded 394 * packets, and thus, even if they are forwarded, the replies will 395 * return back to us. 396 */ 397 if (!forwarding) { 398 /* 399 * Do delayed checksums now because we send before 400 * this is done in the normal processing path. 401 */ 402 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 403 in_delayed_cksum(m); 404 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 405 } 406 #if defined(SCTP) || defined(SCTP_SUPPORT) 407 if (m->m_pkthdr.csum_flags & CSUM_SCTP) { 408 struct ip *ip; 409 410 ip = mtod(m, struct ip *); 411 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 412 m->m_pkthdr.csum_flags &= ~CSUM_SCTP; 413 } 414 #endif 415 } 416 /* NB: callee frees mbuf and releases reference to SP */ 417 error = ipsec4_check_pmtu(m, sp, forwarding); 418 if (error != 0) { 419 if (error == EJUSTRETURN) 420 return (0); 421 422 return (error); 423 } 424 425 error = ipsec4_process_packet(m, sp, inp); 426 if (error == EJUSTRETURN) { 427 /* 428 * We had a SP with a level of 'use' and no SA. We 429 * will just continue to process the packet without 430 * IPsec processing and return without error. 431 */ 432 return (0); 433 } 434 if (error == 0) 435 return (EINPROGRESS); /* consumed by IPsec */ 436 return (error); 437 } 438 439 /* 440 * IPSEC_OUTPUT() method implementation for IPv4. 441 * 0 - no IPsec handling needed 442 * other values - mbuf consumed by IPsec. 443 */ 444 int 445 ipsec4_output(struct mbuf *m, struct inpcb *inp) 446 { 447 448 /* 449 * If the packet is resubmitted to ip_output (e.g. after 450 * AH, ESP, etc. processing), there will be a tag to bypass 451 * the lookup and related policy checking. 452 */ 453 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 454 return (0); 455 456 return (ipsec4_common_output(m, inp, 0)); 457 } 458 459 /* 460 * IPSEC_FORWARD() method implementation for IPv4. 461 * 0 - no IPsec handling needed 462 * other values - mbuf consumed by IPsec. 463 */ 464 int 465 ipsec4_forward(struct mbuf *m) 466 { 467 468 /* 469 * Check if this packet has an active inbound SP and needs to be 470 * dropped instead of forwarded. 471 */ 472 if (ipsec4_in_reject(m, NULL) != 0) { 473 m_freem(m); 474 return (EACCES); 475 } 476 return (ipsec4_common_output(m, NULL, 1)); 477 } 478 #endif 479 480 #ifdef INET6 481 static int 482 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa, 483 const struct in6_addr *ia) 484 { 485 struct in6_addr ia2; 486 487 if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr)) { 488 memcpy(&ia2, &sa->sin6_addr, sizeof(ia2)); 489 ia2.s6_addr16[1] = htons(sa->sin6_scope_id); 490 return (IN6_ARE_ADDR_EQUAL(ia, &ia2)); 491 } 492 return (IN6_ARE_ADDR_EQUAL(&sa->sin6_addr, ia)); 493 } 494 495 static struct secasvar * 496 ipsec6_allocsa(struct mbuf *m, struct secpolicy *sp, u_int *pidx, int *error) 497 { 498 struct secasindex *saidx, tmpsaidx; 499 struct ipsecrequest *isr; 500 struct sockaddr_in6 *sin6; 501 struct secasvar *sav; 502 struct ip6_hdr *ip6; 503 504 /* 505 * Check system global policy controls. 506 */ 507 next: 508 isr = sp->req[*pidx]; 509 if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) || 510 (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) || 511 (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) { 512 DPRINTF(("%s: IPsec outbound packet dropped due" 513 " to policy (check your sysctls)\n", __func__)); 514 IPSEC_OSTAT_INC(isr->saidx.proto, pdrops); 515 *error = EHOSTUNREACH; 516 return (NULL); 517 } 518 /* 519 * Craft SA index to search for proper SA. Note that 520 * we only fillin unspecified SA peers for transport 521 * mode; for tunnel mode they must already be filled in. 522 */ 523 if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) { 524 saidx = &tmpsaidx; 525 *saidx = isr->saidx; 526 ip6 = mtod(m, struct ip6_hdr *); 527 if (saidx->src.sin6.sin6_len == 0) { 528 sin6 = (struct sockaddr_in6 *)&saidx->src; 529 sin6->sin6_len = sizeof(*sin6); 530 sin6->sin6_family = AF_INET6; 531 sin6->sin6_port = IPSEC_PORT_ANY; 532 sin6->sin6_addr = ip6->ip6_src; 533 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) { 534 /* fix scope id for comparing SPD */ 535 sin6->sin6_addr.s6_addr16[1] = 0; 536 sin6->sin6_scope_id = 537 ntohs(ip6->ip6_src.s6_addr16[1]); 538 } 539 } 540 if (saidx->dst.sin6.sin6_len == 0) { 541 sin6 = (struct sockaddr_in6 *)&saidx->dst; 542 sin6->sin6_len = sizeof(*sin6); 543 sin6->sin6_family = AF_INET6; 544 sin6->sin6_port = IPSEC_PORT_ANY; 545 sin6->sin6_addr = ip6->ip6_dst; 546 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) { 547 /* fix scope id for comparing SPD */ 548 sin6->sin6_addr.s6_addr16[1] = 0; 549 sin6->sin6_scope_id = 550 ntohs(ip6->ip6_dst.s6_addr16[1]); 551 } 552 } 553 } else 554 saidx = &sp->req[*pidx]->saidx; 555 /* 556 * Lookup SA and validate it. 557 */ 558 sav = key_allocsa_policy(sp, saidx, error); 559 if (sav == NULL) { 560 IPSEC6STAT_INC(ips_out_nosa); 561 if (*error != 0) 562 return (NULL); 563 if (ipsec_get_reqlevel(sp, *pidx) != IPSEC_LEVEL_REQUIRE) { 564 /* 565 * We have no SA and policy that doesn't require 566 * this IPsec transform, thus we can continue w/o 567 * IPsec processing, i.e. return EJUSTRETURN. 568 * But first check if there is some bundled transform. 569 */ 570 if (sp->tcount > ++(*pidx)) 571 goto next; 572 *error = EJUSTRETURN; 573 } 574 return (NULL); 575 } 576 IPSEC_ASSERT(sav->tdb_xform != NULL, ("SA with NULL tdb_xform")); 577 return (sav); 578 } 579 580 /* 581 * IPsec output logic for IPv6. 582 */ 583 static int 584 ipsec6_perform_request(struct mbuf *m, struct secpolicy *sp, 585 struct inpcb *inp, u_int idx) 586 { 587 struct ipsec_ctx_data ctx; 588 union sockaddr_union *dst; 589 struct secasvar *sav; 590 struct ip6_hdr *ip6; 591 int error, i, off; 592 593 IPSEC_ASSERT(idx < sp->tcount, ("Wrong IPsec request index %d", idx)); 594 595 sav = ipsec6_allocsa(m, sp, &idx, &error); 596 if (sav == NULL) { 597 if (error == EJUSTRETURN) { /* No IPsec required */ 598 key_freesp(&sp); 599 return (error); 600 } 601 goto bad; 602 } 603 604 /* Fix IP length in case if it is not set yet. */ 605 ip6 = mtod(m, struct ip6_hdr *); 606 ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6)); 607 608 IPSEC_INIT_CTX(&ctx, &m, inp, sav, AF_INET6, IPSEC_ENC_BEFORE); 609 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 610 goto bad; 611 612 ip6 = mtod(m, struct ip6_hdr *); /* pfil can change mbuf */ 613 dst = &sav->sah->saidx.dst; 614 615 /* Do the appropriate encapsulation, if necessary */ 616 if (sp->req[idx]->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */ 617 dst->sa.sa_family != AF_INET6 || /* PF mismatch */ 618 ((dst->sa.sa_family == AF_INET6) && 619 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) && 620 (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) { 621 if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) { 622 /* No jumbogram support. */ 623 error = ENXIO; /*XXX*/ 624 goto bad; 625 } 626 error = ipsec_encap(&m, &sav->sah->saidx); 627 if (error != 0) { 628 DPRINTF(("%s: encapsulation for SPI 0x%08x failed " 629 "with error %d\n", __func__, ntohl(sav->spi), 630 error)); 631 /* XXXAE: IPSEC_OSTAT_INC(tunnel); */ 632 goto bad; 633 } 634 inp = NULL; 635 } 636 637 IPSEC_INIT_CTX(&ctx, &m, inp, sav, dst->sa.sa_family, IPSEC_ENC_AFTER); 638 if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_OUT)) != 0) 639 goto bad; 640 641 switch(dst->sa.sa_family) { 642 #ifdef INET 643 case AF_INET: 644 { 645 struct ip *ip; 646 ip = mtod(m, struct ip *); 647 i = ip->ip_hl << 2; 648 off = offsetof(struct ip, ip_p); 649 } 650 break; 651 #endif /* AF_INET */ 652 case AF_INET6: 653 i = sizeof(struct ip6_hdr); 654 off = offsetof(struct ip6_hdr, ip6_nxt); 655 break; 656 default: 657 DPRINTF(("%s: unsupported protocol family %u\n", 658 __func__, dst->sa.sa_family)); 659 error = EPFNOSUPPORT; 660 IPSEC_OSTAT_INC(sav->sah->saidx.proto, nopf); 661 goto bad; 662 } 663 error = (*sav->tdb_xform->xf_output)(m, sp, sav, idx, i, off); 664 return (error); 665 bad: 666 IPSEC6STAT_INC(ips_out_inval); 667 if (m != NULL) 668 m_freem(m); 669 if (sav != NULL) 670 key_freesav(&sav); 671 key_freesp(&sp); 672 return (error); 673 } 674 675 int 676 ipsec6_process_packet(struct mbuf *m, struct secpolicy *sp, 677 struct inpcb *inp) 678 { 679 680 return (ipsec6_perform_request(m, sp, inp, 0)); 681 } 682 683 /* 684 * IPv6 implementation is based on IPv4 implementation. 685 */ 686 int 687 ipsec6_check_pmtu(struct mbuf *m, struct secpolicy *sp, int forwarding) 688 { 689 struct secasvar *sav; 690 size_t hlen, pmtu; 691 uint32_t idx; 692 int error; 693 694 /* 695 * According to RFC8200 L3 fragmentation is supposed to be done only on 696 * locally generated packets. During L3 forwarding packets that are too 697 * big are always supposed to be dropped, with an ICMPv6 packet being 698 * sent back. 699 */ 700 if (!forwarding) 701 return (0); 702 703 idx = sp->tcount - 1; 704 sav = ipsec6_allocsa(m, sp, &idx, &error); 705 if (sav == NULL) { 706 key_freesp(&sp); 707 /* 708 * No matching SA was found and SADB_ACQUIRE message was generated. 709 * Since we have matched a SP to this packet drop it silently. 710 */ 711 if (error == 0) 712 error = EINPROGRESS; 713 if (error != EJUSTRETURN) 714 m_freem(m); 715 716 return (error); 717 } 718 719 pmtu = ipsec_get_pmtu(sav); 720 if (pmtu == 0) { 721 key_freesav(&sav); 722 return (0); 723 } 724 725 hlen = ipsec_hdrsiz_internal(sp); 726 key_freesav(&sav); 727 728 if (m_length(m, NULL) + hlen > pmtu) { 729 /* 730 * If we're forwarding generate ICMPv6 message here, 731 * so that it contains pmtu subtracted by header size. 732 * Set error to EINPROGRESS, in order for the frame 733 * to be dropped silently. 734 */ 735 if (forwarding) { 736 if (pmtu > hlen) 737 icmp6_error(m, ICMP6_PACKET_TOO_BIG, 0, pmtu - hlen); 738 else 739 m_freem(m); 740 741 key_freesp(&sp); 742 return (EINPROGRESS); /* Pretend that we consumed it. */ 743 } 744 } 745 746 return (0); 747 } 748 749 static int 750 ipsec6_common_output(struct mbuf *m, struct inpcb *inp, int forwarding) 751 { 752 struct secpolicy *sp; 753 int error; 754 755 /* Lookup for the corresponding outbound security policy */ 756 sp = ipsec6_checkpolicy(m, inp, &error, !forwarding); 757 if (sp == NULL) { 758 if (error == -EINVAL) { 759 /* Discarded by policy. */ 760 m_freem(m); 761 return (EACCES); 762 } 763 return (0); /* No IPsec required. */ 764 } 765 766 if (!forwarding) { 767 /* 768 * Do delayed checksums now because we send before 769 * this is done in the normal processing path. 770 */ 771 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 772 in6_delayed_cksum(m, m->m_pkthdr.len - 773 sizeof(struct ip6_hdr), sizeof(struct ip6_hdr)); 774 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; 775 } 776 #if defined(SCTP) || defined(SCTP_SUPPORT) 777 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { 778 sctp_delayed_cksum(m, sizeof(struct ip6_hdr)); 779 m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; 780 } 781 #endif 782 } 783 784 error = ipsec6_check_pmtu(m, sp, forwarding); 785 if (error != 0) { 786 if (error == EJUSTRETURN) 787 return (0); 788 789 return (error); 790 } 791 792 /* NB: callee frees mbuf and releases reference to SP */ 793 error = ipsec6_process_packet(m, sp, inp); 794 if (error == EJUSTRETURN) { 795 /* 796 * We had a SP with a level of 'use' and no SA. We 797 * will just continue to process the packet without 798 * IPsec processing and return without error. 799 */ 800 return (0); 801 } 802 if (error == 0) 803 return (EINPROGRESS); /* consumed by IPsec */ 804 return (error); 805 } 806 807 /* 808 * IPSEC_OUTPUT() method implementation for IPv6. 809 * 0 - no IPsec handling needed 810 * other values - mbuf consumed by IPsec. 811 */ 812 int 813 ipsec6_output(struct mbuf *m, struct inpcb *inp) 814 { 815 816 /* 817 * If the packet is resubmitted to ip_output (e.g. after 818 * AH, ESP, etc. processing), there will be a tag to bypass 819 * the lookup and related policy checking. 820 */ 821 if (m_tag_find(m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) 822 return (0); 823 824 return (ipsec6_common_output(m, inp, 0)); 825 } 826 827 /* 828 * IPSEC_FORWARD() method implementation for IPv6. 829 * 0 - no IPsec handling needed 830 * other values - mbuf consumed by IPsec. 831 */ 832 int 833 ipsec6_forward(struct mbuf *m) 834 { 835 836 /* 837 * Check if this packet has an active inbound SP and needs to be 838 * dropped instead of forwarded. 839 */ 840 if (ipsec6_in_reject(m, NULL) != 0) { 841 m_freem(m); 842 return (EACCES); 843 } 844 return (ipsec6_common_output(m, NULL, 1)); 845 } 846 #endif /* INET6 */ 847 848 int 849 ipsec_process_done(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 850 u_int idx) 851 { 852 struct epoch_tracker et; 853 struct xform_history *xh; 854 struct secasindex *saidx; 855 struct m_tag *mtag; 856 int error; 857 858 saidx = &sav->sah->saidx; 859 switch (saidx->dst.sa.sa_family) { 860 #ifdef INET 861 case AF_INET: 862 /* Fix the header length, for AH processing. */ 863 mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len); 864 break; 865 #endif /* INET */ 866 #ifdef INET6 867 case AF_INET6: 868 /* Fix the header length, for AH processing. */ 869 if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) { 870 error = ENXIO; 871 goto bad; 872 } 873 if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) { 874 /* No jumbogram support. */ 875 error = ENXIO; /*?*/ 876 goto bad; 877 } 878 mtod(m, struct ip6_hdr *)->ip6_plen = 879 htons(m->m_pkthdr.len - sizeof(struct ip6_hdr)); 880 break; 881 #endif /* INET6 */ 882 default: 883 DPRINTF(("%s: unknown protocol family %u\n", __func__, 884 saidx->dst.sa.sa_family)); 885 error = ENXIO; 886 goto bad; 887 } 888 889 /* 890 * Add a record of what we've done to the packet. 891 */ 892 mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, sizeof(*xh), M_NOWAIT); 893 if (mtag == NULL) { 894 DPRINTF(("%s: could not get packet tag\n", __func__)); 895 error = ENOMEM; 896 goto bad; 897 } 898 899 xh = (struct xform_history *)(mtag + 1); 900 xh->dst = saidx->dst; 901 xh->proto = saidx->proto; 902 xh->mode = saidx->mode; 903 xh->spi = sav->spi; 904 m_tag_prepend(m, mtag); 905 906 key_sa_recordxfer(sav, m); /* record data transfer */ 907 908 /* 909 * If there's another (bundled) SA to apply, do so. 910 * Note that this puts a burden on the kernel stack size. 911 * If this is a problem we'll need to introduce a queue 912 * to set the packet on so we can unwind the stack before 913 * doing further processing. 914 */ 915 if (++idx < sp->tcount) { 916 switch (saidx->dst.sa.sa_family) { 917 #ifdef INET 918 case AF_INET: 919 key_freesav(&sav); 920 IPSECSTAT_INC(ips_out_bundlesa); 921 return (ipsec4_perform_request(m, sp, NULL, idx)); 922 /* NOTREACHED */ 923 #endif 924 #ifdef INET6 925 case AF_INET6: 926 key_freesav(&sav); 927 IPSEC6STAT_INC(ips_out_bundlesa); 928 return (ipsec6_perform_request(m, sp, NULL, idx)); 929 /* NOTREACHED */ 930 #endif /* INET6 */ 931 default: 932 DPRINTF(("%s: unknown protocol family %u\n", __func__, 933 saidx->dst.sa.sa_family)); 934 error = EPFNOSUPPORT; 935 goto bad; 936 } 937 } 938 939 key_freesp(&sp), sp = NULL; /* Release reference to SP */ 940 #ifdef INET 941 /* 942 * Do UDP encapsulation if SA requires it. 943 */ 944 if (sav->natt != NULL) { 945 error = udp_ipsec_output(m, sav); 946 if (error != 0) 947 goto bad; 948 } 949 #endif /* INET */ 950 /* 951 * We're done with IPsec processing, transmit the packet using the 952 * appropriate network protocol (IP or IPv6). 953 */ 954 NET_EPOCH_ENTER(et); 955 switch (saidx->dst.sa.sa_family) { 956 #ifdef INET 957 case AF_INET: 958 key_freesav(&sav); 959 error = ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL); 960 break; 961 #endif /* INET */ 962 #ifdef INET6 963 case AF_INET6: 964 key_freesav(&sav); 965 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); 966 break; 967 #endif /* INET6 */ 968 default: 969 panic("ipsec_process_done"); 970 } 971 NET_EPOCH_EXIT(et); 972 return (error); 973 bad: 974 m_freem(m); 975 key_freesav(&sav); 976 if (sp != NULL) 977 key_freesp(&sp); 978 return (error); 979 } 980 981 /* 982 * ipsec_prepend() is optimized version of M_PREPEND(). 983 * ipsec_encap() is called by IPsec output routine for tunnel mode SA. 984 * It is expected that after IP encapsulation some IPsec transform will 985 * be performed. Each IPsec transform inserts its variable length header 986 * just after outer IP header using m_makespace(). If given mbuf has not 987 * enough free space at the beginning, we allocate new mbuf and reserve 988 * some space at the beginning and at the end. 989 * This helps avoid allocating of new mbuf and data copying in m_makespace(), 990 * we place outer header in the middle of mbuf's data with reserved leading 991 * and trailing space: 992 * [ LEADINGSPACE ][ Outer IP header ][ TRAILINGSPACE ] 993 * LEADINGSPACE will be used to add ethernet header, TRAILINGSPACE will 994 * be used to inject AH/ESP/IPCOMP header. 995 */ 996 #define IPSEC_TRAILINGSPACE (sizeof(struct udphdr) +/* NAT-T */ \ 997 max(sizeof(struct newesp) + EALG_MAX_BLOCK_LEN, /* ESP + IV */ \ 998 sizeof(struct newah) + HASH_MAX_LEN /* AH + ICV */)) 999 static struct mbuf * 1000 ipsec_prepend(struct mbuf *m, int len, int how) 1001 { 1002 struct mbuf *n; 1003 1004 M_ASSERTPKTHDR(m); 1005 IPSEC_ASSERT(len < MHLEN, ("wrong length")); 1006 if (M_LEADINGSPACE(m) >= len) { 1007 /* No need to allocate new mbuf. */ 1008 m->m_data -= len; 1009 m->m_len += len; 1010 m->m_pkthdr.len += len; 1011 return (m); 1012 } 1013 n = m_gethdr(how, m->m_type); 1014 if (n == NULL) { 1015 m_freem(m); 1016 return (NULL); 1017 } 1018 m_move_pkthdr(n, m); 1019 n->m_next = m; 1020 if (len + IPSEC_TRAILINGSPACE < M_SIZE(n)) 1021 m_align(n, len + IPSEC_TRAILINGSPACE); 1022 n->m_len = len; 1023 n->m_pkthdr.len += len; 1024 return (n); 1025 } 1026 1027 static size_t 1028 ipsec_get_pmtu(struct secasvar *sav) 1029 { 1030 union sockaddr_union *dst; 1031 struct in_conninfo inc; 1032 size_t pmtu; 1033 1034 dst = &sav->sah->saidx.dst; 1035 memset(&inc, 0, sizeof(inc)); 1036 1037 switch (dst->sa.sa_family) { 1038 #ifdef INET 1039 case AF_INET: 1040 inc.inc_faddr = satosin(&dst->sa)->sin_addr; 1041 break; 1042 #endif 1043 #ifdef INET6 1044 case AF_INET6: 1045 inc.inc6_faddr = satosin6(&dst->sa)->sin6_addr; 1046 inc.inc_flags |= INC_ISIPV6; 1047 break; 1048 #endif 1049 default: 1050 return (0); 1051 } 1052 1053 pmtu = tcp_hc_getmtu(&inc); 1054 if (pmtu != 0) 1055 return (pmtu); 1056 1057 /* No entry in hostcache. Assume that PMTU is equal to link's MTU */ 1058 switch (dst->sa.sa_family) { 1059 #ifdef INET 1060 case AF_INET: 1061 pmtu = tcp_maxmtu(&inc, NULL); 1062 break; 1063 #endif 1064 #ifdef INET6 1065 case AF_INET6: 1066 pmtu = tcp_maxmtu6(&inc, NULL); 1067 break; 1068 #endif 1069 default: 1070 return (0); 1071 } 1072 if (pmtu == 0) 1073 return (0); 1074 1075 tcp_hc_updatemtu(&inc, pmtu); 1076 1077 return (pmtu); 1078 } 1079 1080 static int 1081 ipsec_encap(struct mbuf **mp, struct secasindex *saidx) 1082 { 1083 #ifdef INET6 1084 struct ip6_hdr *ip6; 1085 #endif 1086 struct ip *ip; 1087 #ifdef INET 1088 int setdf; 1089 #endif 1090 uint8_t itos, proto; 1091 1092 ip = mtod(*mp, struct ip *); 1093 switch (ip->ip_v) { 1094 #ifdef INET 1095 case IPVERSION: 1096 proto = IPPROTO_IPIP; 1097 /* 1098 * Collect IP_DF state from the inner header 1099 * and honor system-wide control of how to handle it. 1100 */ 1101 switch (V_ip4_ipsec_dfbit) { 1102 case 0: /* clear in outer header */ 1103 case 1: /* set in outer header */ 1104 setdf = V_ip4_ipsec_dfbit; 1105 break; 1106 default:/* propagate to outer header */ 1107 setdf = (ip->ip_off & htons(IP_DF)) != 0; 1108 } 1109 itos = ip->ip_tos; 1110 break; 1111 #endif 1112 #ifdef INET6 1113 case (IPV6_VERSION >> 4): 1114 proto = IPPROTO_IPV6; 1115 ip6 = mtod(*mp, struct ip6_hdr *); 1116 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff; 1117 /* scoped address handling */ 1118 in6_clearscope(&ip6->ip6_src); 1119 in6_clearscope(&ip6->ip6_dst); 1120 break; 1121 #endif 1122 default: 1123 return (EAFNOSUPPORT); 1124 } 1125 switch (saidx->dst.sa.sa_family) { 1126 #ifdef INET 1127 case AF_INET: 1128 if (saidx->src.sa.sa_family != AF_INET || 1129 saidx->src.sin.sin_addr.s_addr == INADDR_ANY || 1130 saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) 1131 return (EINVAL); 1132 *mp = ipsec_prepend(*mp, sizeof(struct ip), M_NOWAIT); 1133 if (*mp == NULL) 1134 return (ENOBUFS); 1135 ip = mtod(*mp, struct ip *); 1136 ip->ip_v = IPVERSION; 1137 ip->ip_hl = sizeof(struct ip) >> 2; 1138 ip->ip_p = proto; 1139 ip->ip_len = htons((*mp)->m_pkthdr.len); 1140 ip->ip_ttl = V_ip_defttl; 1141 ip->ip_sum = 0; 1142 ip->ip_off = setdf ? htons(IP_DF): 0; 1143 ip->ip_src = saidx->src.sin.sin_addr; 1144 ip->ip_dst = saidx->dst.sin.sin_addr; 1145 ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos); 1146 ip_fillid(ip); 1147 break; 1148 #endif /* INET */ 1149 #ifdef INET6 1150 case AF_INET6: 1151 if (saidx->src.sa.sa_family != AF_INET6 || 1152 IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) || 1153 IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr)) 1154 return (EINVAL); 1155 *mp = ipsec_prepend(*mp, sizeof(struct ip6_hdr), M_NOWAIT); 1156 if (*mp == NULL) 1157 return (ENOBUFS); 1158 ip6 = mtod(*mp, struct ip6_hdr *); 1159 ip6->ip6_flow = 0; 1160 ip6->ip6_vfc = IPV6_VERSION; 1161 ip6->ip6_hlim = V_ip6_defhlim; 1162 ip6->ip6_nxt = proto; 1163 ip6->ip6_dst = saidx->dst.sin6.sin6_addr; 1164 /* For link-local address embed scope zone id */ 1165 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) 1166 ip6->ip6_dst.s6_addr16[1] = 1167 htons(saidx->dst.sin6.sin6_scope_id & 0xffff); 1168 ip6->ip6_src = saidx->src.sin6.sin6_addr; 1169 if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) 1170 ip6->ip6_src.s6_addr16[1] = 1171 htons(saidx->src.sin6.sin6_scope_id & 0xffff); 1172 ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6)); 1173 ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos); 1174 ip6->ip6_flow |= htonl((uint32_t)proto << 20); 1175 break; 1176 #endif /* INET6 */ 1177 default: 1178 return (EAFNOSUPPORT); 1179 } 1180 (*mp)->m_flags &= ~(M_BCAST | M_MCAST); 1181 return (0); 1182 }
Cache object: 00109522bc0ac9a872ee9edb190eeef4
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