lib/gssapi/krb5/arcfour.c

   1 /*
   2  * Copyright (c) 2003 - 2006 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   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  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "gsskrb5_locl.h"
  35
  36 /*
  37  * Implements draft-brezak-win2k-krb-rc4-hmac-04.txt
  38  *
  39  * The arcfour message have the following formats:
  40  *
  41  * MIC token
  42  *      TOK_ID[2] = 01 01
  43  *      SGN_ALG[2] = 11 00
  44  *      Filler[4]
  45  *      SND_SEQ[8]
  46  *      SGN_CKSUM[8]
  47  *
  48  * WRAP token
  49  *      TOK_ID[2] = 02 01
  50  *      SGN_ALG[2];
  51  *      SEAL_ALG[2]
  52  *      Filler[2]
  53  *      SND_SEQ[2]
  54  *      SGN_CKSUM[8]
  55  *      Confounder[8]
  56  */
  57
  58 /*
  59  * WRAP in DCE-style have a fixed size header, the oid and length over
  60  * the WRAP header is a total of
  61  * GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE +
  62  * GSS_ARCFOUR_WRAP_TOKEN_SIZE byte (ie total of 45 bytes overhead,
  63  * remember the 2 bytes from APPL [0] SEQ).
  64  */
  65
  66 #define GSS_ARCFOUR_WRAP_TOKEN_SIZE 32
  67 #define GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE 13
  68
  69
  70 static krb5_error_code
  71 arcfour_mic_key(krb5_context context, krb5_keyblock *key,
  72                 void *cksum_data, size_t cksum_size,
  73                 void *key6_data, size_t key6_size)
  74 {
  75     krb5_error_code ret;
  76
  77     Checksum cksum_k5;
  78     krb5_keyblock key5;
  79     char k5_data[16];
  80
  81     Checksum cksum_k6;
  82
  83     char T[4];
  84
  85     memset(T, 0, 4);
  86     cksum_k5.checksum.data = k5_data;
  87     cksum_k5.checksum.length = sizeof(k5_data);
  88
  89     if (key->keytype == KEYTYPE_ARCFOUR_56) {
  90         char L40[14] = "fortybits";
  91
  92         memcpy(L40 + 10, T, sizeof(T));
  93         ret = krb5_hmac(context, CKSUMTYPE_RSA_MD5,
  94                         L40, 14, 0, key, &cksum_k5);
  95         memset(&k5_data[7], 0xAB, 9);
  96     } else {
  97         ret = krb5_hmac(context, CKSUMTYPE_RSA_MD5,
  98                         T, 4, 0, key, &cksum_k5);
  99     }
 100     if (ret)
 101         return ret;
 102
 103     key5.keytype = KEYTYPE_ARCFOUR;
 104     key5.keyvalue = cksum_k5.checksum;
 105
 106     cksum_k6.checksum.data = key6_data;
 107     cksum_k6.checksum.length = key6_size;
 108
 109     return krb5_hmac(context, CKSUMTYPE_RSA_MD5,
 110                      cksum_data, cksum_size, 0, &key5, &cksum_k6);
 111 }
 112
 113
 114 static krb5_error_code
 115 arcfour_mic_cksum(krb5_context context,
 116                   krb5_keyblock *key, unsigned usage,
 117                   u_char *sgn_cksum, size_t sgn_cksum_sz,
 118                   const u_char *v1, size_t l1,
 119                   const void *v2, size_t l2,
 120                   const void *v3, size_t l3)
 121 {
 122     Checksum CKSUM;
 123     u_char *ptr;
 124     size_t len;
 125     krb5_crypto crypto;
 126     krb5_error_code ret;
 127
 128     assert(sgn_cksum_sz == 8);
 129
 130     len = l1 + l2 + l3;
 131
 132     ptr = malloc(len);
 133     if (ptr == NULL)
 134         return ENOMEM;
 135
 136     memcpy(ptr, v1, l1);
 137     memcpy(ptr + l1, v2, l2);
 138     memcpy(ptr + l1 + l2, v3, l3);
 139
 140     ret = krb5_crypto_init(context, key, 0, &crypto);
 141     if (ret) {
 142         free(ptr);
 143         return ret;
 144     }
 145
 146     ret = krb5_create_checksum(context,
 147                                crypto,
 148                                usage,
 149                                0,
 150                                ptr, len,
 151                                &CKSUM);
 152     free(ptr);
 153     if (ret == 0) {
 154         memcpy(sgn_cksum, CKSUM.checksum.data, sgn_cksum_sz);
 155         free_Checksum(&CKSUM);
 156     }
 157     krb5_crypto_destroy(context, crypto);
 158
 159     return ret;
 160 }
 161
 162
 163 OM_uint32
 164 _gssapi_get_mic_arcfour(OM_uint32 * minor_status,
 165                         const gsskrb5_ctx context_handle,
 166                         krb5_context context,
 167                         gss_qop_t qop_req,
 168                         const gss_buffer_t message_buffer,
 169                         gss_buffer_t message_token,
 170                         krb5_keyblock *key)
 171 {
 172     krb5_error_code ret;
 173     int32_t seq_number;
 174     size_t len, total_len;
 175     u_char k6_data[16], *p0, *p;
 176     RC4_KEY rc4_key;
 177
 178     _gsskrb5_encap_length (22, &len, &total_len, GSS_KRB5_MECHANISM);
 179
 180     message_token->length = total_len;
 181     message_token->value  = malloc (total_len);
 182     if (message_token->value == NULL) {
 183         *minor_status = ENOMEM;
 184         return GSS_S_FAILURE;
 185     }
 186
 187     p0 = _gssapi_make_mech_header(message_token->value,
 188                                   len,
 189                                   GSS_KRB5_MECHANISM);
 190     p = p0;
 191
 192     *p++ = 0x01; /* TOK_ID */
 193     *p++ = 0x01;
 194     *p++ = 0x11; /* SGN_ALG */
 195     *p++ = 0x00;
 196     *p++ = 0xff; /* Filler */
 197     *p++ = 0xff;
 198     *p++ = 0xff;
 199     *p++ = 0xff;
 200
 201     p = NULL;
 202
 203     ret = arcfour_mic_cksum(context,
 204                             key, KRB5_KU_USAGE_SIGN,
 205                             p0 + 16, 8,  /* SGN_CKSUM */
 206                             p0, 8, /* TOK_ID, SGN_ALG, Filer */
 207                             message_buffer->value, message_buffer->length,
 208                             NULL, 0);
 209     if (ret) {
 210         _gsskrb5_release_buffer(minor_status, message_token);
 211         *minor_status = ret;
 212         return GSS_S_FAILURE;
 213     }
 214
 215     ret = arcfour_mic_key(context, key,
 216                           p0 + 16, 8, /* SGN_CKSUM */
 217                           k6_data, sizeof(k6_data));
 218     if (ret) {
 219         _gsskrb5_release_buffer(minor_status, message_token);
 220         *minor_status = ret;
 221         return GSS_S_FAILURE;
 222     }
 223
 224     HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 225     krb5_auth_con_getlocalseqnumber (context,
 226                                      context_handle->auth_context,
 227                                      &seq_number);
 228     p = p0 + 8; /* SND_SEQ */
 229     _gsskrb5_encode_be_om_uint32(seq_number, p);
 230
 231     krb5_auth_con_setlocalseqnumber (context,
 232                                      context_handle->auth_context,
 233                                      ++seq_number);
 234     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 235
 236     memset (p + 4, (context_handle->more_flags & LOCAL) ? 0 : 0xff, 4);
 237
 238     RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
 239     RC4 (&rc4_key, 8, p, p);
 240
 241     memset(&rc4_key, 0, sizeof(rc4_key));
 242     memset(k6_data, 0, sizeof(k6_data));
 243
 244     *minor_status = 0;
 245     return GSS_S_COMPLETE;
 246 }
 247
 248
 249 OM_uint32
 250 _gssapi_verify_mic_arcfour(OM_uint32 * minor_status,
 251                            const gsskrb5_ctx context_handle,
 252                            krb5_context context,
 253                            const gss_buffer_t message_buffer,
 254                            const gss_buffer_t token_buffer,
 255                            gss_qop_t * qop_state,
 256                            krb5_keyblock *key,
 257                            char *type)
 258 {
 259     krb5_error_code ret;
 260     uint32_t seq_number;
 261     OM_uint32 omret;
 262     u_char SND_SEQ[8], cksum_data[8], *p;
 263     char k6_data[16];
 264     int cmp;
 265
 266     if (qop_state)
 267         *qop_state = 0;
 268
 269     p = token_buffer->value;
 270     omret = _gsskrb5_verify_header (&p,
 271                                        token_buffer->length,
 272                                        (u_char *)type,
 273                                        GSS_KRB5_MECHANISM);
 274     if (omret)
 275         return omret;
 276
 277     if (memcmp(p, "\x11\x00", 2) != 0) /* SGN_ALG = HMAC MD5 ARCFOUR */
 278         return GSS_S_BAD_SIG;
 279     p += 2;
 280     if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
 281         return GSS_S_BAD_MIC;
 282     p += 4;
 283
 284     ret = arcfour_mic_cksum(context,
 285                             key, KRB5_KU_USAGE_SIGN,
 286                             cksum_data, sizeof(cksum_data),
 287                             p - 8, 8,
 288                             message_buffer->value, message_buffer->length,
 289                             NULL, 0);
 290     if (ret) {
 291         *minor_status = ret;
 292         return GSS_S_FAILURE;
 293     }
 294
 295     ret = arcfour_mic_key(context, key,
 296                           cksum_data, sizeof(cksum_data),
 297                           k6_data, sizeof(k6_data));
 298     if (ret) {
 299         *minor_status = ret;
 300         return GSS_S_FAILURE;
 301     }
 302
 303     cmp = memcmp(cksum_data, p + 8, 8);
 304     if (cmp) {
 305         *minor_status = 0;
 306         return GSS_S_BAD_MIC;
 307     }
 308
 309     {
 310         RC4_KEY rc4_key;
 311
 312         RC4_set_key (&rc4_key, sizeof(k6_data), (void*)k6_data);
 313         RC4 (&rc4_key, 8, p, SND_SEQ);
 314
 315         memset(&rc4_key, 0, sizeof(rc4_key));
 316         memset(k6_data, 0, sizeof(k6_data));
 317     }
 318
 319     _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
 320
 321     if (context_handle->more_flags & LOCAL)
 322         cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
 323     else
 324         cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
 325
 326     memset(SND_SEQ, 0, sizeof(SND_SEQ));
 327     if (cmp != 0) {
 328         *minor_status = 0;
 329         return GSS_S_BAD_MIC;
 330     }
 331
 332     HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 333     omret = _gssapi_msg_order_check(context_handle->order, seq_number);
 334     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 335     if (omret)
 336         return omret;
 337
 338     *minor_status = 0;
 339     return GSS_S_COMPLETE;
 340 }
 341
 342 OM_uint32
 343 _gssapi_wrap_arcfour(OM_uint32 * minor_status,
 344                      const gsskrb5_ctx context_handle,
 345                      krb5_context context,
 346                      int conf_req_flag,
 347                      gss_qop_t qop_req,
 348                      const gss_buffer_t input_message_buffer,
 349                      int * conf_state,
 350                      gss_buffer_t output_message_buffer,
 351                      krb5_keyblock *key)
 352 {
 353     u_char Klocaldata[16], k6_data[16], *p, *p0;
 354     size_t len, total_len, datalen;
 355     krb5_keyblock Klocal;
 356     krb5_error_code ret;
 357     int32_t seq_number;
 358
 359     if (conf_state)
 360         *conf_state = 0;
 361
 362     datalen = input_message_buffer->length;
 363
 364     if (IS_DCE_STYLE(context_handle)) {
 365         len = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 366         _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
 367         total_len += datalen;
 368     } else {
 369         datalen += 1; /* padding */
 370         len = datalen + GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 371         _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
 372     }
 373
 374     output_message_buffer->length = total_len;
 375     output_message_buffer->value  = malloc (total_len);
 376     if (output_message_buffer->value == NULL) {
 377         *minor_status = ENOMEM;
 378         return GSS_S_FAILURE;
 379     }
 380
 381     p0 = _gssapi_make_mech_header(output_message_buffer->value,
 382                                   len,
 383                                   GSS_KRB5_MECHANISM);
 384     p = p0;
 385
 386     *p++ = 0x02; /* TOK_ID */
 387     *p++ = 0x01;
 388     *p++ = 0x11; /* SGN_ALG */
 389     *p++ = 0x00;
 390     if (conf_req_flag) {
 391         *p++ = 0x10; /* SEAL_ALG */
 392         *p++ = 0x00;
 393     } else {
 394         *p++ = 0xff; /* SEAL_ALG */
 395         *p++ = 0xff;
 396     }
 397     *p++ = 0xff; /* Filler */
 398     *p++ = 0xff;
 399
 400     p = NULL;
 401
 402     HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 403     krb5_auth_con_getlocalseqnumber (context,
 404                                      context_handle->auth_context,
 405                                      &seq_number);
 406
 407     _gsskrb5_encode_be_om_uint32(seq_number, p0 + 8);
 408
 409     krb5_auth_con_setlocalseqnumber (context,
 410                                      context_handle->auth_context,
 411                                      ++seq_number);
 412     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 413
 414     memset (p0 + 8 + 4,
 415             (context_handle->more_flags & LOCAL) ? 0 : 0xff,
 416             4);
 417
 418     krb5_generate_random_block(p0 + 24, 8); /* fill in Confounder */
 419
 420     /* p points to data */
 421     p = p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 422     memcpy(p, input_message_buffer->value, input_message_buffer->length);
 423
 424     if (!IS_DCE_STYLE(context_handle))
 425         p[input_message_buffer->length] = 1; /* padding */
 426
 427     ret = arcfour_mic_cksum(context,
 428                             key, KRB5_KU_USAGE_SEAL,
 429                             p0 + 16, 8, /* SGN_CKSUM */
 430                             p0, 8, /* TOK_ID, SGN_ALG, SEAL_ALG, Filler */
 431                             p0 + 24, 8, /* Confounder */
 432                             p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
 433                             datalen);
 434     if (ret) {
 435         *minor_status = ret;
 436         _gsskrb5_release_buffer(minor_status, output_message_buffer);
 437         return GSS_S_FAILURE;
 438     }
 439
 440     {
 441         int i;
 442
 443         Klocal.keytype = key->keytype;
 444         Klocal.keyvalue.data = Klocaldata;
 445         Klocal.keyvalue.length = sizeof(Klocaldata);
 446
 447         for (i = 0; i < 16; i++)
 448             Klocaldata[i] = ((u_char *)key->keyvalue.data)[i] ^ 0xF0;
 449     }
 450     ret = arcfour_mic_key(context, &Klocal,
 451                           p0 + 8, 4, /* SND_SEQ */
 452                           k6_data, sizeof(k6_data));
 453     memset(Klocaldata, 0, sizeof(Klocaldata));
 454     if (ret) {
 455         _gsskrb5_release_buffer(minor_status, output_message_buffer);
 456         *minor_status = ret;
 457         return GSS_S_FAILURE;
 458     }
 459
 460
 461     if(conf_req_flag) {
 462         RC4_KEY rc4_key;
 463
 464         RC4_set_key (&rc4_key, sizeof(k6_data), (void *)k6_data);
 465         /* XXX ? */
 466         RC4 (&rc4_key, 8 + datalen, p0 + 24, p0 + 24); /* Confounder + data */
 467         memset(&rc4_key, 0, sizeof(rc4_key));
 468     }
 469     memset(k6_data, 0, sizeof(k6_data));
 470
 471     ret = arcfour_mic_key(context, key,
 472                           p0 + 16, 8, /* SGN_CKSUM */
 473                           k6_data, sizeof(k6_data));
 474     if (ret) {
 475         _gsskrb5_release_buffer(minor_status, output_message_buffer);
 476         *minor_status = ret;
 477         return GSS_S_FAILURE;
 478     }
 479
 480     {
 481         RC4_KEY rc4_key;
 482
 483         RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
 484         RC4 (&rc4_key, 8, p0 + 8, p0 + 8); /* SND_SEQ */
 485         memset(&rc4_key, 0, sizeof(rc4_key));
 486         memset(k6_data, 0, sizeof(k6_data));
 487     }
 488
 489     if (conf_state)
 490         *conf_state = conf_req_flag;
 491
 492     *minor_status = 0;
 493     return GSS_S_COMPLETE;
 494 }
 495
 496 OM_uint32 _gssapi_unwrap_arcfour(OM_uint32 *minor_status,
 497                                  const gsskrb5_ctx context_handle,
 498                                  krb5_context context,
 499                                  const gss_buffer_t input_message_buffer,
 500                                  gss_buffer_t output_message_buffer,
 501                                  int *conf_state,
 502                                  gss_qop_t *qop_state,
 503                                  krb5_keyblock *key)
 504 {
 505     u_char Klocaldata[16];
 506     krb5_keyblock Klocal;
 507     krb5_error_code ret;
 508     uint32_t seq_number;
 509     size_t datalen;
 510     OM_uint32 omret;
 511     u_char k6_data[16], SND_SEQ[8], Confounder[8];
 512     u_char cksum_data[8];
 513     u_char *p, *p0;
 514     int cmp;
 515     int conf_flag;
 516     size_t padlen = 0, len;
 517
 518     if (conf_state)
 519         *conf_state = 0;
 520     if (qop_state)
 521         *qop_state = 0;
 522
 523     p0 = input_message_buffer->value;
 524
 525     if (IS_DCE_STYLE(context_handle)) {
 526         len = GSS_ARCFOUR_WRAP_TOKEN_SIZE +
 527             GSS_ARCFOUR_WRAP_TOKEN_DCE_DER_HEADER_SIZE;
 528         if (input_message_buffer->length < len)
 529             return GSS_S_BAD_MECH;
 530     } else {
 531         len = input_message_buffer->length;
 532     }
 533
 534     omret = _gssapi_verify_mech_header(&p0,
 535                                        len,
 536                                        GSS_KRB5_MECHANISM);
 537     if (omret)
 538         return omret;
 539
 540     /* length of mech header */
 541     len = (p0 - (u_char *)input_message_buffer->value) +
 542         GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 543
 544     if (len > input_message_buffer->length)
 545         return GSS_S_BAD_MECH;
 546
 547     /* length of data */
 548     datalen = input_message_buffer->length - len;
 549
 550     p = p0;
 551
 552     if (memcmp(p, "\x02\x01", 2) != 0)
 553         return GSS_S_BAD_SIG;
 554     p += 2;
 555     if (memcmp(p, "\x11\x00", 2) != 0) /* SGN_ALG = HMAC MD5 ARCFOUR */
 556         return GSS_S_BAD_SIG;
 557     p += 2;
 558
 559     if (memcmp (p, "\x10\x00", 2) == 0)
 560         conf_flag = 1;
 561     else if (memcmp (p, "\xff\xff", 2) == 0)
 562         conf_flag = 0;
 563     else
 564         return GSS_S_BAD_SIG;
 565
 566     p += 2;
 567     if (memcmp (p, "\xff\xff", 2) != 0)
 568         return GSS_S_BAD_MIC;
 569     p = NULL;
 570
 571     ret = arcfour_mic_key(context, key,
 572                           p0 + 16, 8, /* SGN_CKSUM */
 573                           k6_data, sizeof(k6_data));
 574     if (ret) {
 575         *minor_status = ret;
 576         return GSS_S_FAILURE;
 577     }
 578
 579     {
 580         RC4_KEY rc4_key;
 581
 582         RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
 583         RC4 (&rc4_key, 8, p0 + 8, SND_SEQ); /* SND_SEQ */
 584         memset(&rc4_key, 0, sizeof(rc4_key));
 585         memset(k6_data, 0, sizeof(k6_data));
 586     }
 587
 588     _gsskrb5_decode_be_om_uint32(SND_SEQ, &seq_number);
 589
 590     if (context_handle->more_flags & LOCAL)
 591         cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
 592     else
 593         cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
 594
 595     if (cmp != 0) {
 596         *minor_status = 0;
 597         return GSS_S_BAD_MIC;
 598     }
 599
 600     {
 601         int i;
 602
 603         Klocal.keytype = key->keytype;
 604         Klocal.keyvalue.data = Klocaldata;
 605         Klocal.keyvalue.length = sizeof(Klocaldata);
 606
 607         for (i = 0; i < 16; i++)
 608             Klocaldata[i] = ((u_char *)key->keyvalue.data)[i] ^ 0xF0;
 609     }
 610     ret = arcfour_mic_key(context, &Klocal,
 611                           SND_SEQ, 4,
 612                           k6_data, sizeof(k6_data));
 613     memset(Klocaldata, 0, sizeof(Klocaldata));
 614     if (ret) {
 615         *minor_status = ret;
 616         return GSS_S_FAILURE;
 617     }
 618
 619     output_message_buffer->value = malloc(datalen);
 620     if (output_message_buffer->value == NULL) {
 621         *minor_status = ENOMEM;
 622         return GSS_S_FAILURE;
 623     }
 624     output_message_buffer->length = datalen;
 625
 626     if(conf_flag) {
 627         RC4_KEY rc4_key;
 628
 629         RC4_set_key (&rc4_key, sizeof(k6_data), k6_data);
 630         RC4 (&rc4_key, 8, p0 + 24, Confounder); /* Confounder */
 631         RC4 (&rc4_key, datalen, p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
 632              output_message_buffer->value);
 633         memset(&rc4_key, 0, sizeof(rc4_key));
 634     } else {
 635         memcpy(Confounder, p0 + 24, 8); /* Confounder */
 636         memcpy(output_message_buffer->value,
 637                p0 + GSS_ARCFOUR_WRAP_TOKEN_SIZE,
 638                datalen);
 639     }
 640     memset(k6_data, 0, sizeof(k6_data));
 641
 642     if (!IS_DCE_STYLE(context_handle)) {
 643         ret = _gssapi_verify_pad(output_message_buffer, datalen, &padlen);
 644         if (ret) {
 645             _gsskrb5_release_buffer(minor_status, output_message_buffer);
 646             *minor_status = 0;
 647             return ret;
 648         }
 649         output_message_buffer->length -= padlen;
 650     }
 651
 652     ret = arcfour_mic_cksum(context,
 653                             key, KRB5_KU_USAGE_SEAL,
 654                             cksum_data, sizeof(cksum_data),
 655                             p0, 8,
 656                             Confounder, sizeof(Confounder),
 657                             output_message_buffer->value,
 658                             output_message_buffer->length + padlen);
 659     if (ret) {
 660         _gsskrb5_release_buffer(minor_status, output_message_buffer);
 661         *minor_status = ret;
 662         return GSS_S_FAILURE;
 663     }
 664
 665     cmp = memcmp(cksum_data, p0 + 16, 8); /* SGN_CKSUM */
 666     if (cmp) {
 667         _gsskrb5_release_buffer(minor_status, output_message_buffer);
 668         *minor_status = 0;
 669         return GSS_S_BAD_MIC;
 670     }
 671
 672     HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 673     omret = _gssapi_msg_order_check(context_handle->order, seq_number);
 674     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 675     if (omret)
 676         return omret;
 677
 678     if (conf_state)
 679         *conf_state = conf_flag;
 680
 681     *minor_status = 0;
 682     return GSS_S_COMPLETE;
 683 }
 684
 685 static OM_uint32
 686 max_wrap_length_arcfour(const gsskrb5_ctx ctx,
 687                         krb5_crypto crypto,
 688                         size_t input_length,
 689                         OM_uint32 *max_input_size)
 690 {
 691     /*
 692      * if GSS_C_DCE_STYLE is in use:
 693      *  - we only need to encapsulate the WRAP token
 694      * However, since this is a fixed since, we just
 695      */
 696     if (IS_DCE_STYLE(ctx)) {
 697         size_t len, total_len;
 698
 699         len = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 700         _gssapi_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
 701
 702         if (input_length < len)
 703             *max_input_size = 0;
 704         else
 705             *max_input_size = input_length - len;
 706
 707     } else {
 708         size_t extrasize = GSS_ARCFOUR_WRAP_TOKEN_SIZE;
 709         size_t blocksize = 8;
 710         size_t len, total_len;
 711
 712         len = 8 + input_length + blocksize + extrasize;
 713
 714         _gsskrb5_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
 715
 716         total_len -= input_length; /* token length */
 717         if (total_len < input_length) {
 718             *max_input_size = (input_length - total_len);
 719             (*max_input_size) &= (~(OM_uint32)(blocksize - 1));
 720         } else {
 721             *max_input_size = 0;
 722         }
 723     }
 724
 725     return GSS_S_COMPLETE;
 726 }
 727
 728 OM_uint32
 729 _gssapi_wrap_size_arcfour(OM_uint32 *minor_status,
 730                           const gsskrb5_ctx ctx,
 731                           krb5_context context,
 732                           int conf_req_flag,
 733                           gss_qop_t qop_req,
 734                           OM_uint32 req_output_size,
 735                           OM_uint32 *max_input_size,
 736                           krb5_keyblock *key)
 737 {
 738     krb5_error_code ret;
 739     krb5_crypto crypto;
 740
 741     ret = krb5_crypto_init(context, key, 0, &crypto);
 742     if (ret != 0) {
 743         *minor_status = ret;
 744         return GSS_S_FAILURE;
 745     }
 746
 747     ret = max_wrap_length_arcfour(ctx, crypto,
 748                                   req_output_size, max_input_size);
 749     if (ret != 0) {
 750         *minor_status = ret;
 751         krb5_crypto_destroy(context, crypto);
 752         return GSS_S_FAILURE;
 753     }
 754
 755     krb5_crypto_destroy(context, crypto);
 756
 757     return GSS_S_COMPLETE;
 758 }