sys/netproto/ipsec/xform_ah.c

   1 /*      $FreeBSD: src/sys/netipsec/xform_ah.c,v 1.1.4.2 2003/02/26 00:14:05 sam Exp $   */
   2 /*      $DragonFly: src/sys/netproto/ipsec/xform_ah.c,v 1.10 2006/10/12 01:32:51 hsu Exp $      */
   3 /*      $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */
   4 /*
   5  * The authors of this code are John Ioannidis (ji@tla.org),
   6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
   7  * Niels Provos (provos@physnet.uni-hamburg.de).
   8  *
   9  * The original version of this code was written by John Ioannidis
  10  * for BSD/OS in Athens, Greece, in November 1995.
  11  *
  12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
  13  * by Angelos D. Keromytis.
  14  *
  15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
  16  * and Niels Provos.
  17  *
  18  * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
  19  *
  20  * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
  21  * Angelos D. Keromytis and Niels Provos.
  22  * Copyright (c) 1999 Niklas Hallqvist.
  23  * Copyright (c) 2001 Angelos D. Keromytis.
  24  *
  25  * Permission to use, copy, and modify this software with or without fee
  26  * is hereby granted, provided that this entire notice is included in
  27  * all copies of any software which is or includes a copy or
  28  * modification of this software.
  29  * You may use this code under the GNU public license if you so wish. Please
  30  * contribute changes back to the authors under this freer than GPL license
  31  * so that we may further the use of strong encryption without limitations to
  32  * all.
  33  *
  34  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  35  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  36  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  37  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  38  * PURPOSE.
  39  */
  40 #include "opt_inet.h"
  41 #include "opt_inet6.h"
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/socket.h>
  47 #include <sys/syslog.h>
  48 #include <sys/kernel.h>
  49 #include <sys/sysctl.h>
  50
  51 #include <net/if.h>
  52
  53 #include <netinet/in.h>
  54 #include <netinet/in_systm.h>
  55 #include <netinet/ip.h>
  56 #include <netinet/ip_ecn.h>
  57 #include <netinet/ip6.h>
  58
  59 #include <net/route.h>
  60 #include <netproto/ipsec/ipsec.h>
  61 #include <netproto/ipsec/ah.h>
  62 #include <netproto/ipsec/ah_var.h>
  63 #include <netproto/ipsec/xform.h>
  64
  65 #ifdef INET6
  66 #include <netinet6/ip6_var.h>
  67 #include <netproto/ipsec/ipsec6.h>
  68 #include <netinet6/ip6_ecn.h>
  69 #endif
  70
  71 #include <netproto/ipsec/key.h>
  72 #include <netproto/ipsec/key_debug.h>
  73
  74 #include <opencrypto/cryptodev.h>
  75
  76 /*
  77  * Return header size in bytes.  The old protocol did not support
  78  * the replay counter; the new protocol always includes the counter.
  79  */
  80 #define HDRSIZE(sav) \
  81         (((sav)->flags & SADB_X_EXT_OLD) ? \
  82                 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
  83 /*
  84  * Return authenticator size in bytes.  The old protocol is known
  85  * to use a fixed 16-byte authenticator.  The new algorithm gets
  86  * this size from the xform but is (currently) always 12.
  87  */
  88 #define AUTHSIZE(sav) \
  89         ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)
  90
  91 int     ah_enable = 1;                  /* control flow of packets with AH */
  92 int     ah_cleartos = 1;                /* clear ip_tos when doing AH calc */
  93 struct  ahstat ahstat;
  94
  95 SYSCTL_DECL(_net_inet_ah);
  96 SYSCTL_INT(_net_inet_ah, OID_AUTO,
  97         ah_enable,      CTLFLAG_RW,     &ah_enable,     0, "");
  98 SYSCTL_INT(_net_inet_ah, OID_AUTO,
  99         ah_cleartos,    CTLFLAG_RW,     &ah_cleartos,   0, "");
 100 SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
 101         stats,          CTLFLAG_RD,     &ahstat,        ahstat, "");
 102
 103 static unsigned char ipseczeroes[256];  /* larger than an ip6 extension hdr */
 104
 105 static int ah_input_cb(struct cryptop*);
 106 static int ah_output_cb(struct cryptop*);
 107
 108 /*
 109  * NB: this is public for use by the PF_KEY support.
 110  */
 111 struct auth_hash *
 112 ah_algorithm_lookup(int alg)
 113 {
 114         if (alg >= AH_ALG_MAX)
 115                 return NULL;
 116         switch (alg) {
 117         case SADB_X_AALG_NULL:
 118                 return &auth_hash_null;
 119         case SADB_AALG_MD5HMAC:
 120                 return &auth_hash_hmac_md5_96;
 121         case SADB_AALG_SHA1HMAC:
 122                 return &auth_hash_hmac_sha1_96;
 123         case SADB_X_AALG_RIPEMD160HMAC:
 124                 return &auth_hash_hmac_ripemd_160_96;
 125         case SADB_X_AALG_MD5:
 126                 return &auth_hash_key_md5;
 127         case SADB_X_AALG_SHA:
 128                 return &auth_hash_key_sha1;
 129         case SADB_X_AALG_SHA2_256:
 130                 return &auth_hash_hmac_sha2_256;
 131         case SADB_X_AALG_SHA2_384:
 132                 return &auth_hash_hmac_sha2_384;
 133         case SADB_X_AALG_SHA2_512:
 134                 return &auth_hash_hmac_sha2_512;
 135         }
 136         return NULL;
 137 }
 138
 139 size_t
 140 ah_hdrsiz(struct secasvar *sav)
 141 {
 142         size_t size;
 143
 144         if (sav != NULL) {
 145                 int authsize;
 146                 KASSERT(sav->tdb_authalgxform != NULL,
 147                         ("ah_hdrsiz: null xform"));
 148                 /*XXX not right for null algorithm--does it matter??*/
 149                 authsize = AUTHSIZE(sav);
 150                 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
 151         } else {
 152                 /* default guess */
 153                 size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
 154         }
 155         return size;
 156 }
 157
 158 /*
 159  * NB: public for use by esp_init.
 160  */
 161 int
 162 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
 163 {
 164         struct auth_hash *thash;
 165         int keylen;
 166
 167         thash = ah_algorithm_lookup(sav->alg_auth);
 168         if (thash == NULL) {
 169                 DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
 170                         sav->alg_auth));
 171                 return EINVAL;
 172         }
 173         /*
 174          * Verify the replay state block allocation is consistent with
 175          * the protocol type.  We check here so we can make assumptions
 176          * later during protocol processing.
 177          */
 178         /* NB: replay state is setup elsewhere (sigh) */
 179         if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
 180                 DPRINTF(("ah_init: replay state block inconsistency, "
 181                         "%s algorithm %s replay state\n",
 182                         (sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
 183                         sav->replay == NULL ? "without" : "with"));
 184                 return EINVAL;
 185         }
 186         if (sav->key_auth == NULL) {
 187                 DPRINTF(("ah_init: no authentication key for %s "
 188                         "algorithm\n", thash->name));
 189                 return EINVAL;
 190         }
 191         keylen = _KEYLEN(sav->key_auth);
 192         if (keylen != thash->keysize && thash->keysize != 0) {
 193                 DPRINTF(("ah_init: invalid keylength %d, algorithm "
 194                          "%s requires keysize %d\n",
 195                          keylen, thash->name, thash->keysize));
 196                 return EINVAL;
 197         }
 198
 199         sav->tdb_xform = xsp;
 200         sav->tdb_authalgxform = thash;
 201
 202         /* Initialize crypto session. */
 203         bzero(cria, sizeof (*cria));
 204         cria->cri_alg = sav->tdb_authalgxform->type;
 205         cria->cri_klen = _KEYBITS(sav->key_auth);
 206         cria->cri_key = _KEYBUF(sav->key_auth);
 207
 208         return 0;
 209 }
 210
 211 /*
 212  * ah_init() is called when an SPI is being set up.
 213  */
 214 static int
 215 ah_init(struct secasvar *sav, struct xformsw *xsp)
 216 {
 217         struct cryptoini cria;
 218         int error;
 219
 220         error = ah_init0(sav, xsp, &cria);
 221         return error ? error :
 222                  crypto_newsession(&sav->tdb_cryptoid, &cria, crypto_support);
 223 }
 224
 225 /*
 226  * Paranoia.
 227  *
 228  * NB: public for use by esp_zeroize (XXX).
 229  */
 230 int
 231 ah_zeroize(struct secasvar *sav)
 232 {
 233         int err;
 234
 235         if (sav->key_auth)
 236                 bzero(_KEYBUF(sav->key_auth), _KEYLEN(sav->key_auth));
 237
 238         err = crypto_freesession(sav->tdb_cryptoid);
 239         sav->tdb_cryptoid = 0;
 240         sav->tdb_authalgxform = NULL;
 241         sav->tdb_xform = NULL;
 242         return err;
 243 }
 244
 245 /*
 246  * Massage IPv4/IPv6 headers for AH processing.
 247  */
 248 static int
 249 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
 250 {
 251         struct mbuf *m = *m0;
 252         unsigned char *ptr;
 253         int off, count;
 254
 255 #ifdef INET
 256         struct ip *ip;
 257 #endif /* INET */
 258
 259 #ifdef INET6
 260         struct ip6_ext *ip6e;
 261         struct ip6_hdr ip6;
 262         int alloc, len, ad;
 263 #endif /* INET6 */
 264
 265         switch (proto) {
 266 #ifdef INET
 267         case AF_INET:
 268                 /*
 269                  * This is the least painful way of dealing with IPv4 header
 270                  * and option processing -- just make sure they're in
 271                  * contiguous memory.
 272                  */
 273                 *m0 = m = m_pullup(m, skip);
 274                 if (m == NULL) {
 275                         DPRINTF(("ah_massage_headers: m_pullup failed\n"));
 276                         return ENOBUFS;
 277                 }
 278
 279                 /* Fix the IP header */
 280                 ip = mtod(m, struct ip *);
 281                 if (ah_cleartos)
 282                         ip->ip_tos = 0;
 283                 ip->ip_ttl = 0;
 284                 ip->ip_sum = 0;
 285
 286                 /*
 287                  * On input, fix ip_len which has been byte-swapped
 288                  * at ip_input().
 289                  */
 290                 if (!out) {
 291                         ip->ip_len = htons(ip->ip_len + skip);
 292
 293                         if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
 294                                 ip->ip_off = htons(ip->ip_off & IP_DF);
 295                         else
 296                                 ip->ip_off = 0;
 297                 } else {
 298                         if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
 299                                 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF);
 300                         else
 301                                 ip->ip_off = 0;
 302                 }
 303
 304                 ptr = mtod(m, unsigned char *) + sizeof(struct ip);
 305
 306                 /* IPv4 option processing */
 307                 for (off = sizeof(struct ip); off < skip;) {
 308                         if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
 309                             off + 1 < skip)
 310                                 ;
 311                         else {
 312                                 DPRINTF(("ah_massage_headers: illegal IPv4 "
 313                                     "option length for option %d\n",
 314                                     ptr[off]));
 315
 316                                 m_freem(m);
 317                                 return EINVAL;
 318                         }
 319
 320                         switch (ptr[off]) {
 321                         case IPOPT_EOL:
 322                                 off = skip;  /* End the loop. */
 323                                 break;
 324
 325                         case IPOPT_NOP:
 326                                 off++;
 327                                 break;
 328
 329                         case IPOPT_SECURITY:    /* 0x82 */
 330                         case 0x85:      /* Extended security. */
 331                         case 0x86:      /* Commercial security. */
 332                         case 0x94:      /* Router alert */
 333                         case 0x95:      /* RFC1770 */
 334                                 /* Sanity check for option length. */
 335                                 if (ptr[off + 1] < 2) {
 336                                         DPRINTF(("ah_massage_headers: "
 337                                             "illegal IPv4 option length for "
 338                                             "option %d\n", ptr[off]));
 339
 340                                         m_freem(m);
 341                                         return EINVAL;
 342                                 }
 343
 344                                 off += ptr[off + 1];
 345                                 break;
 346
 347                         case IPOPT_LSRR:
 348                         case IPOPT_SSRR:
 349                                 /* Sanity check for option length. */
 350                                 if (ptr[off + 1] < 2) {
 351                                         DPRINTF(("ah_massage_headers: "
 352                                             "illegal IPv4 option length for "
 353                                             "option %d\n", ptr[off]));
 354
 355                                         m_freem(m);
 356                                         return EINVAL;
 357                                 }
 358
 359                                 /*
 360                                  * On output, if we have either of the
 361                                  * source routing options, we should
 362                                  * swap the destination address of the
 363                                  * IP header with the last address
 364                                  * specified in the option, as that is
 365                                  * what the destination's IP header
 366                                  * will look like.
 367                                  */
 368                                 if (out)
 369                                         bcopy(ptr + off + ptr[off + 1] -
 370                                             sizeof(struct in_addr),
 371                                             &(ip->ip_dst), sizeof(struct in_addr));
 372
 373                                 /* Fall through */
 374                         default:
 375                                 /* Sanity check for option length. */
 376                                 if (ptr[off + 1] < 2) {
 377                                         DPRINTF(("ah_massage_headers: "
 378                                             "illegal IPv4 option length for "
 379                                             "option %d\n", ptr[off]));
 380                                         m_freem(m);
 381                                         return EINVAL;
 382                                 }
 383
 384                                 /* Zeroize all other options. */
 385                                 count = ptr[off + 1];
 386                                 bcopy(ipseczeroes, ptr, count);
 387                                 off += count;
 388                                 break;
 389                         }
 390
 391                         /* Sanity check. */
 392                         if (off > skip) {
 393                                 DPRINTF(("ah_massage_headers(): malformed "
 394                                     "IPv4 options header\n"));
 395
 396                                 m_freem(m);
 397                                 return EINVAL;
 398                         }
 399                 }
 400
 401                 break;
 402 #endif /* INET */
 403
 404 #ifdef INET6
 405         case AF_INET6:  /* Ugly... */
 406                 /* Copy and "cook" the IPv6 header. */
 407                 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
 408
 409                 /* We don't do IPv6 Jumbograms. */
 410                 if (ip6.ip6_plen == 0) {
 411                         DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
 412                         m_freem(m);
 413                         return EMSGSIZE;
 414                 }
 415
 416                 ip6.ip6_flow = 0;
 417                 ip6.ip6_hlim = 0;
 418                 ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
 419                 ip6.ip6_vfc |= IPV6_VERSION;
 420
 421                 /* Scoped address handling. */
 422                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
 423                         ip6.ip6_src.s6_addr16[1] = 0;
 424                 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
 425                         ip6.ip6_dst.s6_addr16[1] = 0;
 426
 427                 /* Done with IPv6 header. */
 428                 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
 429
 430                 /* Let's deal with the remaining headers (if any). */
 431                 if (skip - sizeof(struct ip6_hdr) > 0) {
 432                         if (m->m_len <= skip) {
 433                                 ptr = kmalloc(skip - sizeof(struct ip6_hdr),
 434                                             M_XDATA, M_INTWAIT | M_NULLOK);
 435                                 if (ptr == NULL) {
 436                                         DPRINTF(("ah_massage_headers: failed "
 437                                             "to allocate memory for IPv6 "
 438                                             "headers\n"));
 439                                         m_freem(m);
 440                                         return ENOBUFS;
 441                                 }
 442
 443                                 /*
 444                                  * Copy all the protocol headers after
 445                                  * the IPv6 header.
 446                                  */
 447                                 m_copydata(m, sizeof(struct ip6_hdr),
 448                                     skip - sizeof(struct ip6_hdr), ptr);
 449                                 alloc = 1;
 450                         } else {
 451                                 /* No need to allocate memory. */
 452                                 ptr = mtod(m, unsigned char *) +
 453                                     sizeof(struct ip6_hdr);
 454                                 alloc = 0;
 455                         }
 456                 } else
 457                         break;
 458
 459                 off = ip6.ip6_nxt & 0xff; /* Next header type. */
 460
 461                 for (len = 0; len < skip - sizeof(struct ip6_hdr);)
 462                         switch (off) {
 463                         case IPPROTO_HOPOPTS:
 464                         case IPPROTO_DSTOPTS:
 465                                 ip6e = (struct ip6_ext *) (ptr + len);
 466
 467                                 /*
 468                                  * Process the mutable/immutable
 469                                  * options -- borrows heavily from the
 470                                  * KAME code.
 471                                  */
 472                                 for (count = len + sizeof(struct ip6_ext);
 473                                      count < len + ((ip6e->ip6e_len + 1) << 3);) {
 474                                         if (ptr[count] == IP6OPT_PAD1) {
 475                                                 count++;
 476                                                 continue; /* Skip padding. */
 477                                         }
 478
 479                                         /* Sanity check. */
 480                                         if (count > len +
 481                                             ((ip6e->ip6e_len + 1) << 3)) {
 482                                                 m_freem(m);
 483
 484                                                 /* Free, if we allocated. */
 485                                                 if (alloc)
 486                                                         FREE(ptr, M_XDATA);
 487                                                 return EINVAL;
 488                                         }
 489
 490                                         ad = ptr[count + 1];
 491
 492                                         /* If mutable option, zeroize. */
 493                                         if (ptr[count] & IP6OPT_MUTABLE)
 494                                                 bcopy(ipseczeroes, ptr + count,
 495                                                     ptr[count + 1]);
 496
 497                                         count += ad;
 498
 499                                         /* Sanity check. */
 500                                         if (count >
 501                                             skip - sizeof(struct ip6_hdr)) {
 502                                                 m_freem(m);
 503
 504                                                 /* Free, if we allocated. */
 505                                                 if (alloc)
 506                                                         FREE(ptr, M_XDATA);
 507                                                 return EINVAL;
 508                                         }
 509                                 }
 510
 511                                 /* Advance. */
 512                                 len += ((ip6e->ip6e_len + 1) << 3);
 513                                 off = ip6e->ip6e_nxt;
 514                                 break;
 515
 516                         case IPPROTO_ROUTING:
 517                                 /*
 518                                  * Always include routing headers in
 519                                  * computation.
 520                                  */
 521                                 ip6e = (struct ip6_ext *) (ptr + len);
 522                                 len += ((ip6e->ip6e_len + 1) << 3);
 523                                 off = ip6e->ip6e_nxt;
 524                                 break;
 525
 526                         default:
 527                                 DPRINTF(("ah_massage_headers: unexpected "
 528                                     "IPv6 header type %d", off));
 529                                 if (alloc)
 530                                         FREE(ptr, M_XDATA);
 531                                 m_freem(m);
 532                                 return EINVAL;
 533                         }
 534
 535                 /* Copyback and free, if we allocated. */
 536                 if (alloc) {
 537                         m_copyback(m, sizeof(struct ip6_hdr),
 538                             skip - sizeof(struct ip6_hdr), ptr);
 539                         kfree(ptr, M_XDATA);
 540                 }
 541
 542                 break;
 543 #endif /* INET6 */
 544         }
 545
 546         return 0;
 547 }
 548
 549 /*
 550  * ah_input() gets called to verify that an input packet
 551  * passes authentication.
 552  */
 553 static int
 554 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
 555 {
 556         struct auth_hash *ahx;
 557         struct tdb_ident *tdbi;
 558         struct tdb_crypto *tc;
 559         struct m_tag *mtag;
 560         struct newah *ah;
 561         int hl, rplen, authsize;
 562
 563         struct cryptodesc *crda;
 564         struct cryptop *crp;
 565
 566         KASSERT(sav != NULL, ("ah_input: null SA"));
 567         KASSERT(sav->key_auth != NULL,
 568                 ("ah_input: null authentication key"));
 569         KASSERT(sav->tdb_authalgxform != NULL,
 570                 ("ah_input: null authentication xform"));
 571
 572         /* Figure out header size. */
 573         rplen = HDRSIZE(sav);
 574
 575         /* XXX don't pullup, just copy header */
 576         IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
 577         if (ah == NULL) {
 578                 DPRINTF(("ah_input: cannot pullup header\n"));
 579                 ahstat.ahs_hdrops++;            /*XXX*/
 580                 m_freem(m);
 581                 return ENOBUFS;
 582         }
 583
 584         /* Check replay window, if applicable. */
 585         if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
 586                 ahstat.ahs_replay++;
 587                 DPRINTF(("ah_input: packet replay failure: %s\n",
 588                           ipsec_logsastr(sav)));
 589                 m_freem(m);
 590                 return ENOBUFS;
 591         }
 592
 593         /* Verify AH header length. */
 594         hl = ah->ah_len * sizeof (u_int32_t);
 595         ahx = sav->tdb_authalgxform;
 596         authsize = AUTHSIZE(sav);
 597         if (hl != authsize + rplen - sizeof (struct ah)) {
 598                 DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
 599                         " for packet in SA %s/%08lx\n",
 600                         hl, (u_long) (authsize + rplen - sizeof (struct ah)),
 601                         ipsec_address(&sav->sah->saidx.dst),
 602                         (u_long) ntohl(sav->spi)));
 603                 ahstat.ahs_badauthl++;
 604                 m_freem(m);
 605                 return EACCES;
 606         }
 607         ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl;
 608
 609         /* Get crypto descriptors. */
 610         crp = crypto_getreq(1);
 611         if (crp == NULL) {
 612                 DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
 613                 ahstat.ahs_crypto++;
 614                 m_freem(m);
 615                 return ENOBUFS;
 616         }
 617
 618         crda = crp->crp_desc;
 619         KASSERT(crda != NULL, ("ah_input: null crypto descriptor"));
 620
 621         crda->crd_skip = 0;
 622         crda->crd_len = m->m_pkthdr.len;
 623         crda->crd_inject = skip + rplen;
 624
 625         /* Authentication operation. */
 626         crda->crd_alg = ahx->type;
 627         crda->crd_key = _KEYBUF(sav->key_auth);
 628         crda->crd_klen = _KEYBITS(sav->key_auth);
 629
 630         /* Find out if we've already done crypto. */
 631         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
 632              mtag != NULL;
 633              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
 634                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 635                 if (tdbi->proto == sav->sah->saidx.proto &&
 636                     tdbi->spi == sav->spi &&
 637                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
 638                           sizeof (union sockaddr_union)))
 639                         break;
 640         }
 641
 642         /* Allocate IPsec-specific opaque crypto info. */
 643         if (mtag == NULL) {
 644                 tc = kmalloc(sizeof (struct tdb_crypto) +
 645                         skip + rplen + authsize, M_XDATA,
 646                         M_INTWAIT | M_ZERO | M_NULLOK);
 647         } else {
 648                 /* Hash verification has already been done successfully. */
 649                 tc = kmalloc(sizeof (struct tdb_crypto),
 650                         M_XDATA, M_INTWAIT | M_ZERO | M_NULLOK);
 651         }
 652         if (tc == NULL) {
 653                 DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
 654                 ahstat.ahs_crypto++;
 655                 crypto_freereq(crp);
 656                 m_freem(m);
 657                 return ENOBUFS;
 658         }
 659
 660         /* Only save information if crypto processing is needed. */
 661         if (mtag == NULL) {
 662                 int error;
 663
 664                 /*
 665                  * Save the authenticator, the skipped portion of the packet,
 666                  * and the AH header.
 667                  */
 668                 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1));
 669
 670                 /* Zeroize the authenticator on the packet. */
 671                 m_copyback(m, skip + rplen, authsize, ipseczeroes);
 672
 673                 /* "Massage" the packet headers for crypto processing. */
 674                 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
 675                     skip, ahx->type, 0);
 676                 if (error != 0) {
 677                         /* NB: mbuf is free'd by ah_massage_headers */
 678                         ahstat.ahs_hdrops++;
 679                         kfree(tc, M_XDATA);
 680                         crypto_freereq(crp);
 681                         return error;
 682                 }
 683         }
 684
 685         /* Crypto operation descriptor. */
 686         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
 687         crp->crp_flags = CRYPTO_F_IMBUF;
 688         crp->crp_buf = (caddr_t) m;
 689         crp->crp_callback = ah_input_cb;
 690         crp->crp_sid = sav->tdb_cryptoid;
 691         crp->crp_opaque = (caddr_t) tc;
 692
 693         /* These are passed as-is to the callback. */
 694         tc->tc_spi = sav->spi;
 695         tc->tc_dst = sav->sah->saidx.dst;
 696         tc->tc_proto = sav->sah->saidx.proto;
 697         tc->tc_nxt = ah->ah_nxt;
 698         tc->tc_protoff = protoff;
 699         tc->tc_skip = skip;
 700         tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */
 701
 702         if (mtag == NULL)
 703                 return crypto_dispatch(crp);
 704         else
 705                 return ah_input_cb(crp);
 706 }
 707
 708 #ifdef INET6
 709 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
 710         if (saidx->dst.sa.sa_family == AF_INET6) {                           \
 711                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
 712         } else {                                                             \
 713                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
 714         }                                                                    \
 715 } while (0)
 716 #else
 717 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
 718         (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
 719 #endif
 720
 721 /*
 722  * AH input callback from the crypto driver.
 723  */
 724 static int
 725 ah_input_cb(struct cryptop *crp)
 726 {
 727         int rplen, error, skip, protoff;
 728         unsigned char calc[AH_ALEN_MAX];
 729         struct mbuf *m;
 730         struct cryptodesc *crd;
 731         struct auth_hash *ahx;
 732         struct tdb_crypto *tc;
 733         struct m_tag *mtag;
 734         struct secasvar *sav;
 735         struct secasindex *saidx;
 736         u_int8_t nxt;
 737         caddr_t ptr;
 738         int authsize;
 739
 740         crd = crp->crp_desc;
 741
 742         tc = (struct tdb_crypto *) crp->crp_opaque;
 743         KASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
 744         skip = tc->tc_skip;
 745         nxt = tc->tc_nxt;
 746         protoff = tc->tc_protoff;
 747         mtag = (struct m_tag *) tc->tc_ptr;
 748         m = (struct mbuf *) crp->crp_buf;
 749
 750         crit_enter();
 751
 752         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
 753         if (sav == NULL) {
 754                 ahstat.ahs_notdb++;
 755                 DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
 756                 error = ENOBUFS;                /*XXX*/
 757                 goto bad;
 758         }
 759
 760         saidx = &sav->sah->saidx;
 761         KASSERT(saidx->dst.sa.sa_family == AF_INET ||
 762                 saidx->dst.sa.sa_family == AF_INET6,
 763                 ("ah_input_cb: unexpected protocol family %u",
 764                  saidx->dst.sa.sa_family));
 765
 766         ahx = (struct auth_hash *) sav->tdb_authalgxform;
 767
 768         /* Check for crypto errors. */
 769         if (crp->crp_etype) {
 770                 if (sav->tdb_cryptoid != 0)
 771                         sav->tdb_cryptoid = crp->crp_sid;
 772
 773                 if (crp->crp_etype == EAGAIN)
 774                         return crypto_dispatch(crp);
 775
 776                 ahstat.ahs_noxform++;
 777                 DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
 778                 error = crp->crp_etype;
 779                 goto bad;
 780         } else {
 781                 ahstat.ahs_hist[sav->alg_auth]++;
 782                 crypto_freereq(crp);            /* No longer needed. */
 783                 crp = NULL;
 784         }
 785
 786         /* Shouldn't happen... */
 787         if (m == NULL) {
 788                 ahstat.ahs_crypto++;
 789                 DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
 790                 error = EINVAL;
 791                 goto bad;
 792         }
 793
 794         /* Figure out header size. */
 795         rplen = HDRSIZE(sav);
 796         authsize = AUTHSIZE(sav);
 797
 798         /* Copy authenticator off the packet. */
 799         m_copydata(m, skip + rplen, authsize, calc);
 800
 801         /*
 802          * If we have an mtag, we don't need to verify the authenticator --
 803          * it has been verified by an IPsec-aware NIC.
 804          */
 805         if (mtag == NULL) {
 806                 ptr = (caddr_t) (tc + 1);
 807
 808                 /* Verify authenticator. */
 809                 if (bcmp(ptr + skip + rplen, calc, authsize)) {
 810                         DPRINTF(("ah_input: authentication hash mismatch "
 811                             "for packet in SA %s/%08lx\n",
 812                             ipsec_address(&saidx->dst),
 813                             (u_long) ntohl(sav->spi)));
 814                         ahstat.ahs_badauth++;
 815                         error = EACCES;
 816                         goto bad;
 817                 }
 818
 819                 /* Fix the Next Protocol field. */
 820                 ((u_int8_t *) ptr)[protoff] = nxt;
 821
 822                 /* Copyback the saved (uncooked) network headers. */
 823                 m_copyback(m, 0, skip, ptr);
 824         } else {
 825                 /* Fix the Next Protocol field. */
 826                 m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
 827         }
 828
 829         kfree(tc, M_XDATA), tc = NULL;                  /* No longer needed */
 830
 831         /*
 832          * Header is now authenticated.
 833          */
 834         m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
 835
 836         /*
 837          * Update replay sequence number, if appropriate.
 838          */
 839         if (sav->replay) {
 840                 u_int32_t seq;
 841
 842                 m_copydata(m, skip + offsetof(struct newah, ah_seq),
 843                            sizeof (seq), (caddr_t) &seq);
 844                 if (ipsec_updatereplay(ntohl(seq), sav)) {
 845                         ahstat.ahs_replay++;
 846                         error = ENOBUFS;                        /*XXX as above*/
 847                         goto bad;
 848                 }
 849         }
 850
 851         /*
 852          * Remove the AH header and authenticator from the mbuf.
 853          */
 854         error = m_striphdr(m, skip, rplen + authsize);
 855         if (error) {
 856                 DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
 857                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
 858
 859                 ahstat.ahs_hdrops++;
 860                 goto bad;
 861         }
 862
 863         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
 864
 865         KEY_FREESAV(&sav);
 866         crit_exit();
 867         return error;
 868 bad:
 869         if (sav)
 870                 KEY_FREESAV(&sav);
 871         crit_exit();
 872         if (m != NULL)
 873                 m_freem(m);
 874         if (tc != NULL)
 875                 kfree(tc, M_XDATA);
 876         if (crp != NULL)
 877                 crypto_freereq(crp);
 878         return error;
 879 }
 880
 881 /*
 882  * AH output routine, called by ipsec[46]_process_packet().
 883  */
 884 static int
 885 ah_output(
 886         struct mbuf *m,
 887         struct ipsecrequest *isr,
 888         struct mbuf **mp,
 889         int skip,
 890         int protoff)
 891 {
 892         struct secasvar *sav;
 893         struct auth_hash *ahx;
 894         struct cryptodesc *crda;
 895         struct tdb_crypto *tc;
 896         struct mbuf *mi;
 897         struct cryptop *crp;
 898         u_int16_t iplen;
 899         int error, rplen, authsize, maxpacketsize, roff;
 900         u_int8_t prot;
 901         struct newah *ah;
 902
 903         sav = isr->sav;
 904         KASSERT(sav != NULL, ("ah_output: null SA"));
 905         ahx = sav->tdb_authalgxform;
 906         KASSERT(ahx != NULL, ("ah_output: null authentication xform"));
 907
 908         ahstat.ahs_output++;
 909
 910         /* Figure out header size. */
 911         rplen = HDRSIZE(sav);
 912
 913         /* Check for maximum packet size violations. */
 914         switch (sav->sah->saidx.dst.sa.sa_family) {
 915 #ifdef INET
 916         case AF_INET:
 917                 maxpacketsize = IP_MAXPACKET;
 918                 break;
 919 #endif /* INET */
 920 #ifdef INET6
 921         case AF_INET6:
 922                 maxpacketsize = IPV6_MAXPACKET;
 923                 break;
 924 #endif /* INET6 */
 925         default:
 926                 DPRINTF(("ah_output: unknown/unsupported protocol "
 927                     "family %u, SA %s/%08lx\n",
 928                     sav->sah->saidx.dst.sa.sa_family,
 929                     ipsec_address(&sav->sah->saidx.dst),
 930                     (u_long) ntohl(sav->spi)));
 931                 ahstat.ahs_nopf++;
 932                 error = EPFNOSUPPORT;
 933                 goto bad;
 934         }
 935         authsize = AUTHSIZE(sav);
 936         if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
 937                 DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
 938                     "(len %u, max len %u)\n",
 939                     ipsec_address(&sav->sah->saidx.dst),
 940                     (u_long) ntohl(sav->spi),
 941                     rplen + authsize + m->m_pkthdr.len, maxpacketsize));
 942                 ahstat.ahs_toobig++;
 943                 error = EMSGSIZE;
 944                 goto bad;
 945         }
 946
 947         /* Update the counters. */
 948         ahstat.ahs_obytes += m->m_pkthdr.len - skip;
 949
 950         m = m_clone(m);
 951         if (m == NULL) {
 952                 DPRINTF(("ah_output: cannot clone mbuf chain, SA %s/%08lx\n",
 953                     ipsec_address(&sav->sah->saidx.dst),
 954                     (u_long) ntohl(sav->spi)));
 955                 ahstat.ahs_hdrops++;
 956                 error = ENOBUFS;
 957                 goto bad;
 958         }
 959
 960         /* Inject AH header. */
 961         mi = m_makespace(m, skip, rplen + authsize, &roff);
 962         if (mi == NULL) {
 963                 DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
 964                     "%s/%08lx\n",
 965                     rplen + authsize,
 966                     ipsec_address(&sav->sah->saidx.dst),
 967                     (u_long) ntohl(sav->spi)));
 968                 ahstat.ahs_hdrops++;            /*XXX differs from openbsd */
 969                 error = ENOBUFS;
 970                 goto bad;
 971         }
 972
 973         /*
 974          * The AH header is guaranteed by m_makespace() to be in
 975          * contiguous memory, at roff bytes offset into the returned mbuf.
 976          */
 977         ah = (struct newah *)(mtod(mi, caddr_t) + roff);
 978
 979         /* Initialize the AH header. */
 980         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
 981         ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
 982         ah->ah_reserve = 0;
 983         ah->ah_spi = sav->spi;
 984
 985         /* Zeroize authenticator. */
 986         m_copyback(m, skip + rplen, authsize, ipseczeroes);
 987
 988         /* Insert packet replay counter, as requested.  */
 989         if (sav->replay) {
 990                 if (sav->replay->count == ~0 &&
 991                     (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
 992                         DPRINTF(("ah_output: replay counter wrapped for SA "
 993                                 "%s/%08lx\n",
 994                                 ipsec_address(&sav->sah->saidx.dst),
 995                                 (u_long) ntohl(sav->spi)));
 996                         ahstat.ahs_wrap++;
 997                         error = EINVAL;
 998                         goto bad;
 999                 }
1000                 sav->replay->count++;
1001                 ah->ah_seq = htonl(sav->replay->count);
1002         }
1003
1004         /* Get crypto descriptors. */
1005         crp = crypto_getreq(1);
1006         if (crp == NULL) {
1007                 DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
1008                 ahstat.ahs_crypto++;
1009                 error = ENOBUFS;
1010                 goto bad;
1011         }
1012
1013         crda = crp->crp_desc;
1014
1015         crda->crd_skip = 0;
1016         crda->crd_inject = skip + rplen;
1017         crda->crd_len = m->m_pkthdr.len;
1018
1019         /* Authentication operation. */
1020         crda->crd_alg = ahx->type;
1021         crda->crd_key = _KEYBUF(sav->key_auth);
1022         crda->crd_klen = _KEYBITS(sav->key_auth);
1023
1024         /* Allocate IPsec-specific opaque crypto info. */
1025         tc = kmalloc(sizeof(struct tdb_crypto) + skip, M_XDATA,
1026                 M_INTWAIT | M_ZERO | M_NULLOK);
1027         if (tc == NULL) {
1028                 crypto_freereq(crp);
1029                 DPRINTF(("ah_output: failed to allocate tdb_crypto\n"));
1030                 ahstat.ahs_crypto++;
1031                 error = ENOBUFS;
1032                 goto bad;
1033         }
1034
1035         /* Save the skipped portion of the packet. */
1036         m_copydata(m, 0, skip, (caddr_t) (tc + 1));
1037
1038         /*
1039          * Fix IP header length on the header used for
1040          * authentication. We don't need to fix the original
1041          * header length as it will be fixed by our caller.
1042          */
1043         switch (sav->sah->saidx.dst.sa.sa_family) {
1044 #ifdef INET
1045         case AF_INET:
1046                 bcopy(((caddr_t)(tc + 1)) +
1047                     offsetof(struct ip, ip_len),
1048                     (caddr_t) &iplen, sizeof(u_int16_t));
1049                 iplen = htons(ntohs(iplen) + rplen + authsize);
1050                 m_copyback(m, offsetof(struct ip, ip_len),
1051                     sizeof(u_int16_t), (caddr_t) &iplen);
1052                 break;
1053 #endif /* INET */
1054
1055 #ifdef INET6
1056         case AF_INET6:
1057                 bcopy(((caddr_t)(tc + 1)) +
1058                     offsetof(struct ip6_hdr, ip6_plen),
1059                     (caddr_t) &iplen, sizeof(u_int16_t));
1060                 iplen = htons(ntohs(iplen) + rplen + authsize);
1061                 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1062                     sizeof(u_int16_t), (caddr_t) &iplen);
1063                 break;
1064 #endif /* INET6 */
1065         }
1066
1067         /* Fix the Next Header field in saved header. */
1068         ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1069
1070         /* Update the Next Protocol field in the IP header. */
1071         prot = IPPROTO_AH;
1072         m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot);
1073
1074         /* "Massage" the packet headers for crypto processing. */
1075         error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1076                         skip, ahx->type, 1);
1077         if (error != 0) {
1078                 m = NULL;       /* mbuf was free'd by ah_massage_headers. */
1079                 kfree(tc, M_XDATA);
1080                 crypto_freereq(crp);
1081                 goto bad;
1082         }
1083
1084         /* Crypto operation descriptor. */
1085         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1086         crp->crp_flags = CRYPTO_F_IMBUF;
1087         crp->crp_buf = (caddr_t) m;
1088         crp->crp_callback = ah_output_cb;
1089         crp->crp_sid = sav->tdb_cryptoid;
1090         crp->crp_opaque = (caddr_t) tc;
1091
1092         /* These are passed as-is to the callback. */
1093         tc->tc_isr = isr;
1094         tc->tc_spi = sav->spi;
1095         tc->tc_dst = sav->sah->saidx.dst;
1096         tc->tc_proto = sav->sah->saidx.proto;
1097         tc->tc_skip = skip;
1098         tc->tc_protoff = protoff;
1099
1100         return crypto_dispatch(crp);
1101 bad:
1102         if (m)
1103                 m_freem(m);
1104         return (error);
1105 }
1106
1107 /*
1108  * AH output callback from the crypto driver.
1109  */
1110 static int
1111 ah_output_cb(struct cryptop *crp)
1112 {
1113         int skip, protoff, error;
1114         struct tdb_crypto *tc;
1115         struct ipsecrequest *isr;
1116         struct secasvar *sav;
1117         struct mbuf *m;
1118         caddr_t ptr;
1119         int err;
1120
1121         tc = (struct tdb_crypto *) crp->crp_opaque;
1122         KASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
1123         skip = tc->tc_skip;
1124         protoff = tc->tc_protoff;
1125         ptr = (caddr_t) (tc + 1);
1126         m = (struct mbuf *) crp->crp_buf;
1127
1128         crit_enter();
1129
1130         isr = tc->tc_isr;
1131         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
1132         if (sav == NULL) {
1133                 ahstat.ahs_notdb++;
1134                 DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
1135                 error = ENOBUFS;                /*XXX*/
1136                 goto bad;
1137         }
1138         KASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));
1139
1140         /* Check for crypto errors. */
1141         if (crp->crp_etype) {
1142                 if (sav->tdb_cryptoid != 0)
1143                         sav->tdb_cryptoid = crp->crp_sid;
1144
1145                 if (crp->crp_etype == EAGAIN) {
1146                         KEY_FREESAV(&sav);
1147                         crit_exit();
1148                         return crypto_dispatch(crp);
1149                 }
1150
1151                 ahstat.ahs_noxform++;
1152                 DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
1153                 error = crp->crp_etype;
1154                 goto bad;
1155         }
1156
1157         /* Shouldn't happen... */
1158         if (m == NULL) {
1159                 ahstat.ahs_crypto++;
1160                 DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
1161                 error = EINVAL;
1162                 goto bad;
1163         }
1164         ahstat.ahs_hist[sav->alg_auth]++;
1165
1166         /*
1167          * Copy original headers (with the new protocol number) back
1168          * in place.
1169          */
1170         m_copyback(m, 0, skip, ptr);
1171
1172         /* No longer needed. */
1173         kfree(tc, M_XDATA);
1174         crypto_freereq(crp);
1175
1176         /* NB: m is reclaimed by ipsec_process_done. */
1177         err = ipsec_process_done(m, isr);
1178         KEY_FREESAV(&sav);
1179         crit_exit();
1180         return err;
1181 bad:
1182         if (sav)
1183                 KEY_FREESAV(&sav);
1184         crit_exit();
1185         if (m)
1186                 m_freem(m);
1187         kfree(tc, M_XDATA);
1188         crypto_freereq(crp);
1189         return error;
1190 }
1191
1192 static struct xformsw ah_xformsw = {
1193         XF_AH,          XFT_AUTH,       "IPsec AH",
1194         ah_init,        ah_zeroize,     ah_input,       ah_output,
1195 };
1196
1197 static void
1198 ah_attach(void)
1199 {
1200         xform_register(&ah_xformsw);
1201 }
1202 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);