root/source4/heimdal/lib/gssapi/krb5/wrap.c

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DEFINITIONS

This source file includes following definitions.
  1. _gsskrb5i_get_initiator_subkey
  2. _gsskrb5i_get_acceptor_subkey
  3. _gsskrb5i_get_token_key
  4. sub_wrap_size
  5. _gsskrb5_wrap_size_limit

   1 /*
   2  * Copyright (c) 1997 - 2003 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 "krb5/gsskrb5_locl.h"
  35 
  36 RCSID("$Id$");
  37 
  38 /*
  39  * Return initiator subkey, or if that doesn't exists, the subkey.
  40  */
  41 
  42 krb5_error_code
  43 _gsskrb5i_get_initiator_subkey(const gsskrb5_ctx ctx,
     /* [<][>][^][v][top][bottom][index][help] */
  44                                krb5_context context,
  45                                krb5_keyblock **key)
  46 {
  47     krb5_error_code ret;
  48     *key = NULL;
  49 
  50     if (ctx->more_flags & LOCAL) {
  51         ret = krb5_auth_con_getlocalsubkey(context,
  52                                      ctx->auth_context,
  53                                      key);
  54     } else {
  55         ret = krb5_auth_con_getremotesubkey(context,
  56                                       ctx->auth_context,
  57                                       key);
  58     }
  59     if (ret == 0 && *key == NULL)
  60         ret = krb5_auth_con_getkey(context,
  61                                    ctx->auth_context,
  62                                    key);
  63     if (ret == 0 && *key == NULL) {
  64         krb5_set_error_message(context, 0, "No initiator subkey available");
  65         return GSS_KRB5_S_KG_NO_SUBKEY;
  66     }
  67     return ret;
  68 }
  69 
  70 krb5_error_code
  71 _gsskrb5i_get_acceptor_subkey(const gsskrb5_ctx ctx,
     /* [<][>][^][v][top][bottom][index][help] */
  72                               krb5_context context,
  73                               krb5_keyblock **key)
  74 {
  75     krb5_error_code ret;
  76     *key = NULL;
  77 
  78     if (ctx->more_flags & LOCAL) {
  79         ret = krb5_auth_con_getremotesubkey(context,
  80                                       ctx->auth_context,
  81                                       key);
  82     } else {
  83         ret = krb5_auth_con_getlocalsubkey(context,
  84                                      ctx->auth_context,
  85                                      key);
  86     }
  87     if (ret == 0 && *key == NULL) {
  88         krb5_set_error_message(context, 0, "No acceptor subkey available");
  89         return GSS_KRB5_S_KG_NO_SUBKEY;
  90     }
  91     return ret;
  92 }
  93 
  94 OM_uint32
  95 _gsskrb5i_get_token_key(const gsskrb5_ctx ctx,
     /* [<][>][^][v][top][bottom][index][help] */
  96                         krb5_context context,
  97                         krb5_keyblock **key)
  98 {
  99     _gsskrb5i_get_acceptor_subkey(ctx, context, key);
 100     if(*key == NULL) {
 101         /*
 102          * Only use the initiator subkey or ticket session key if an
 103          * acceptor subkey was not required.
 104          */
 105         if ((ctx->more_flags & ACCEPTOR_SUBKEY) == 0)
 106             _gsskrb5i_get_initiator_subkey(ctx, context, key);
 107     }
 108     if (*key == NULL) {
 109         krb5_set_error_message(context, 0, "No token key available");
 110         return GSS_KRB5_S_KG_NO_SUBKEY;
 111     }
 112     return 0;
 113 }
 114 
 115 static OM_uint32
 116 sub_wrap_size (
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 117             OM_uint32 req_output_size,
 118             OM_uint32 * max_input_size,
 119             int blocksize,
 120             int extrasize
 121            )
 122 {
 123     size_t len, total_len;
 124 
 125     len = 8 + req_output_size + blocksize + extrasize;
 126 
 127     _gsskrb5_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
 128 
 129     total_len -= req_output_size; /* token length */
 130     if (total_len < req_output_size) {
 131         *max_input_size = (req_output_size - total_len);
 132         (*max_input_size) &= (~(OM_uint32)(blocksize - 1));
 133     } else {
 134         *max_input_size = 0;
 135     }
 136     return GSS_S_COMPLETE;
 137 }
 138 
 139 OM_uint32
 140 _gsskrb5_wrap_size_limit (
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 141             OM_uint32 * minor_status,
 142             const gss_ctx_id_t context_handle,
 143             int conf_req_flag,
 144             gss_qop_t qop_req,
 145             OM_uint32 req_output_size,
 146             OM_uint32 * max_input_size
 147            )
 148 {
 149   krb5_context context;
 150   krb5_keyblock *key;
 151   OM_uint32 ret;
 152   krb5_keytype keytype;
 153   const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
 154 
 155   GSSAPI_KRB5_INIT (&context);
 156 
 157   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 158   ret = _gsskrb5i_get_token_key(ctx, context, &key);
 159   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 160   if (ret) {
 161       *minor_status = ret;
 162       return GSS_S_FAILURE;
 163   }
 164   krb5_enctype_to_keytype (context, key->keytype, &keytype);
 165 
 166   switch (keytype) {
 167   case KEYTYPE_DES :
 168       ret = sub_wrap_size(req_output_size, max_input_size, 8, 22);
 169       break;
 170   case KEYTYPE_ARCFOUR:
 171   case KEYTYPE_ARCFOUR_56:
 172       ret = _gssapi_wrap_size_arcfour(minor_status, ctx, context,
 173                                       conf_req_flag, qop_req,
 174                                       req_output_size, max_input_size, key);
 175       break;
 176   case KEYTYPE_DES3 :
 177       ret = sub_wrap_size(req_output_size, max_input_size, 8, 34);
 178       break;
 179   default :
 180       ret = _gssapi_wrap_size_cfx(minor_status, ctx, context,
 181                                   conf_req_flag, qop_req,
 182                                   req_output_size, max_input_size, key);
 183       break;
 184   }
 185   krb5_free_keyblock (context, key);
 186   *minor_status = 0;
 187   return ret;
 188 }
 189 
 190 static OM_uint32
 191 wrap_des
 192            (OM_uint32 * minor_status,
 193             const gsskrb5_ctx ctx,
 194             krb5_context context,
 195             int conf_req_flag,
 196             gss_qop_t qop_req,
 197             const gss_buffer_t input_message_buffer,
 198             int * conf_state,
 199             gss_buffer_t output_message_buffer,
 200             krb5_keyblock *key
 201            )
 202 {
 203   u_char *p;
 204   MD5_CTX md5;
 205   u_char hash[16];
 206   DES_key_schedule schedule;
 207   DES_cblock deskey;
 208   DES_cblock zero;
 209   int i;
 210   int32_t seq_number;
 211   size_t len, total_len, padlength, datalen;
 212 
 213   if (IS_DCE_STYLE(ctx)) {
 214     padlength = 0;
 215     datalen = input_message_buffer->length;
 216     len = 22 + 8;
 217     _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
 218     total_len += datalen;
 219     datalen += 8;
 220   } else {
 221     padlength = 8 - (input_message_buffer->length % 8);
 222     datalen = input_message_buffer->length + padlength + 8;
 223     len = datalen + 22;
 224     _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
 225   }
 226 
 227   output_message_buffer->length = total_len;
 228   output_message_buffer->value  = malloc (total_len);
 229   if (output_message_buffer->value == NULL) {
 230     output_message_buffer->length = 0;
 231     *minor_status = ENOMEM;
 232     return GSS_S_FAILURE;
 233   }
 234 
 235   p = _gsskrb5_make_header(output_message_buffer->value,
 236                               len,
 237                               "\x02\x01", /* TOK_ID */
 238                               GSS_KRB5_MECHANISM);
 239 
 240   /* SGN_ALG */
 241   memcpy (p, "\x00\x00", 2);
 242   p += 2;
 243   /* SEAL_ALG */
 244   if(conf_req_flag)
 245       memcpy (p, "\x00\x00", 2);
 246   else
 247       memcpy (p, "\xff\xff", 2);
 248   p += 2;
 249   /* Filler */
 250   memcpy (p, "\xff\xff", 2);
 251   p += 2;
 252 
 253   /* fill in later */
 254   memset (p, 0, 16);
 255   p += 16;
 256 
 257   /* confounder + data + pad */
 258   krb5_generate_random_block(p, 8);
 259   memcpy (p + 8, input_message_buffer->value,
 260           input_message_buffer->length);
 261   memset (p + 8 + input_message_buffer->length, padlength, padlength);
 262 
 263   /* checksum */
 264   MD5_Init (&md5);
 265   MD5_Update (&md5, p - 24, 8);
 266   MD5_Update (&md5, p, datalen);
 267   MD5_Final (hash, &md5);
 268 
 269   memset (&zero, 0, sizeof(zero));
 270   memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 271   DES_set_key_unchecked (&deskey, &schedule);
 272   DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
 273                  &schedule, &zero);
 274   memcpy (p - 8, hash, 8);
 275 
 276   /* sequence number */
 277   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 278   krb5_auth_con_getlocalseqnumber (context,
 279                                    ctx->auth_context,
 280                                    &seq_number);
 281 
 282   p -= 16;
 283   p[0] = (seq_number >> 0)  & 0xFF;
 284   p[1] = (seq_number >> 8)  & 0xFF;
 285   p[2] = (seq_number >> 16) & 0xFF;
 286   p[3] = (seq_number >> 24) & 0xFF;
 287   memset (p + 4,
 288           (ctx->more_flags & LOCAL) ? 0 : 0xFF,
 289           4);
 290 
 291   DES_set_key_unchecked (&deskey, &schedule);
 292   DES_cbc_encrypt ((void *)p, (void *)p, 8,
 293                    &schedule, (DES_cblock *)(p + 8), DES_ENCRYPT);
 294 
 295   krb5_auth_con_setlocalseqnumber (context,
 296                                ctx->auth_context,
 297                                ++seq_number);
 298   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 299 
 300   /* encrypt the data */
 301   p += 16;
 302 
 303   if(conf_req_flag) {
 304       memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 305 
 306       for (i = 0; i < sizeof(deskey); ++i)
 307           deskey[i] ^= 0xf0;
 308       DES_set_key_unchecked (&deskey, &schedule);
 309       memset (&zero, 0, sizeof(zero));
 310       DES_cbc_encrypt ((void *)p,
 311                        (void *)p,
 312                        datalen,
 313                        &schedule,
 314                        &zero,
 315                        DES_ENCRYPT);
 316   }
 317   memset (deskey, 0, sizeof(deskey));
 318   memset (&schedule, 0, sizeof(schedule));
 319 
 320   if(conf_state != NULL)
 321       *conf_state = conf_req_flag;
 322   *minor_status = 0;
 323   return GSS_S_COMPLETE;
 324 }
 325 
 326 static OM_uint32
 327 wrap_des3
 328            (OM_uint32 * minor_status,
 329             const gsskrb5_ctx ctx,
 330             krb5_context context,
 331             int conf_req_flag,
 332             gss_qop_t qop_req,
 333             const gss_buffer_t input_message_buffer,
 334             int * conf_state,
 335             gss_buffer_t output_message_buffer,
 336             krb5_keyblock *key
 337            )
 338 {
 339   u_char *p;
 340   u_char seq[8];
 341   int32_t seq_number;
 342   size_t len, total_len, padlength, datalen;
 343   uint32_t ret;
 344   krb5_crypto crypto;
 345   Checksum cksum;
 346   krb5_data encdata;
 347 
 348   if (IS_DCE_STYLE(ctx)) {
 349     padlength = 0;
 350     datalen = input_message_buffer->length;
 351     len = 34 + 8;
 352     _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
 353     total_len += datalen;
 354     datalen += 8;
 355   } else {
 356     padlength = 8 - (input_message_buffer->length % 8);
 357     datalen = input_message_buffer->length + padlength + 8;
 358     len = datalen + 34;
 359     _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
 360   }
 361 
 362   output_message_buffer->length = total_len;
 363   output_message_buffer->value  = malloc (total_len);
 364   if (output_message_buffer->value == NULL) {
 365     output_message_buffer->length = 0;
 366     *minor_status = ENOMEM;
 367     return GSS_S_FAILURE;
 368   }
 369 
 370   p = _gsskrb5_make_header(output_message_buffer->value,
 371                               len,
 372                               "\x02\x01", /* TOK_ID */
 373                               GSS_KRB5_MECHANISM);
 374 
 375   /* SGN_ALG */
 376   memcpy (p, "\x04\x00", 2);    /* HMAC SHA1 DES3-KD */
 377   p += 2;
 378   /* SEAL_ALG */
 379   if(conf_req_flag)
 380       memcpy (p, "\x02\x00", 2); /* DES3-KD */
 381   else
 382       memcpy (p, "\xff\xff", 2);
 383   p += 2;
 384   /* Filler */
 385   memcpy (p, "\xff\xff", 2);
 386   p += 2;
 387 
 388   /* calculate checksum (the above + confounder + data + pad) */
 389 
 390   memcpy (p + 20, p - 8, 8);
 391   krb5_generate_random_block(p + 28, 8);
 392   memcpy (p + 28 + 8, input_message_buffer->value,
 393           input_message_buffer->length);
 394   memset (p + 28 + 8 + input_message_buffer->length, padlength, padlength);
 395 
 396   ret = krb5_crypto_init(context, key, 0, &crypto);
 397   if (ret) {
 398       free (output_message_buffer->value);
 399       output_message_buffer->length = 0;
 400       output_message_buffer->value = NULL;
 401       *minor_status = ret;
 402       return GSS_S_FAILURE;
 403   }
 404 
 405   ret = krb5_create_checksum (context,
 406                               crypto,
 407                               KRB5_KU_USAGE_SIGN,
 408                               0,
 409                               p + 20,
 410                               datalen + 8,
 411                               &cksum);
 412   krb5_crypto_destroy (context, crypto);
 413   if (ret) {
 414       free (output_message_buffer->value);
 415       output_message_buffer->length = 0;
 416       output_message_buffer->value = NULL;
 417       *minor_status = ret;
 418       return GSS_S_FAILURE;
 419   }
 420 
 421   /* zero out SND_SEQ + SGN_CKSUM in case */
 422   memset (p, 0, 28);
 423 
 424   memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
 425   free_Checksum (&cksum);
 426 
 427   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 428   /* sequence number */
 429   krb5_auth_con_getlocalseqnumber (context,
 430                                ctx->auth_context,
 431                                &seq_number);
 432 
 433   seq[0] = (seq_number >> 0)  & 0xFF;
 434   seq[1] = (seq_number >> 8)  & 0xFF;
 435   seq[2] = (seq_number >> 16) & 0xFF;
 436   seq[3] = (seq_number >> 24) & 0xFF;
 437   memset (seq + 4,
 438           (ctx->more_flags & LOCAL) ? 0 : 0xFF,
 439           4);
 440 
 441 
 442   ret = krb5_crypto_init(context, key, ETYPE_DES3_CBC_NONE,
 443                          &crypto);
 444   if (ret) {
 445       free (output_message_buffer->value);
 446       output_message_buffer->length = 0;
 447       output_message_buffer->value = NULL;
 448       *minor_status = ret;
 449       return GSS_S_FAILURE;
 450   }
 451 
 452   {
 453       DES_cblock ivec;
 454 
 455       memcpy (&ivec, p + 8, 8);
 456       ret = krb5_encrypt_ivec (context,
 457                                crypto,
 458                                KRB5_KU_USAGE_SEQ,
 459                                seq, 8, &encdata,
 460                                &ivec);
 461   }
 462   krb5_crypto_destroy (context, crypto);
 463   if (ret) {
 464       free (output_message_buffer->value);
 465       output_message_buffer->length = 0;
 466       output_message_buffer->value = NULL;
 467       *minor_status = ret;
 468       return GSS_S_FAILURE;
 469   }
 470 
 471   assert (encdata.length == 8);
 472 
 473   memcpy (p, encdata.data, encdata.length);
 474   krb5_data_free (&encdata);
 475 
 476   krb5_auth_con_setlocalseqnumber (context,
 477                                ctx->auth_context,
 478                                ++seq_number);
 479   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 480 
 481   /* encrypt the data */
 482   p += 28;
 483 
 484   if(conf_req_flag) {
 485       krb5_data tmp;
 486 
 487       ret = krb5_crypto_init(context, key,
 488                              ETYPE_DES3_CBC_NONE, &crypto);
 489       if (ret) {
 490           free (output_message_buffer->value);
 491           output_message_buffer->length = 0;
 492           output_message_buffer->value = NULL;
 493           *minor_status = ret;
 494           return GSS_S_FAILURE;
 495       }
 496       ret = krb5_encrypt(context, crypto, KRB5_KU_USAGE_SEAL,
 497                          p, datalen, &tmp);
 498       krb5_crypto_destroy(context, crypto);
 499       if (ret) {
 500           free (output_message_buffer->value);
 501           output_message_buffer->length = 0;
 502           output_message_buffer->value = NULL;
 503           *minor_status = ret;
 504           return GSS_S_FAILURE;
 505       }
 506       assert (tmp.length == datalen);
 507 
 508       memcpy (p, tmp.data, datalen);
 509       krb5_data_free(&tmp);
 510   }
 511   if(conf_state != NULL)
 512       *conf_state = conf_req_flag;
 513   *minor_status = 0;
 514   return GSS_S_COMPLETE;
 515 }
 516 
 517 OM_uint32 _gsskrb5_wrap
 518            (OM_uint32 * minor_status,
 519             const gss_ctx_id_t context_handle,
 520             int conf_req_flag,
 521             gss_qop_t qop_req,
 522             const gss_buffer_t input_message_buffer,
 523             int * conf_state,
 524             gss_buffer_t output_message_buffer
 525            )
 526 {
 527   krb5_context context;
 528   krb5_keyblock *key;
 529   OM_uint32 ret;
 530   krb5_keytype keytype;
 531   const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
 532 
 533   GSSAPI_KRB5_INIT (&context);
 534 
 535   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 536   ret = _gsskrb5i_get_token_key(ctx, context, &key);
 537   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 538   if (ret) {
 539       *minor_status = ret;
 540       return GSS_S_FAILURE;
 541   }
 542   krb5_enctype_to_keytype (context, key->keytype, &keytype);
 543 
 544   switch (keytype) {
 545   case KEYTYPE_DES :
 546       ret = wrap_des (minor_status, ctx, context, conf_req_flag,
 547                       qop_req, input_message_buffer, conf_state,
 548                       output_message_buffer, key);
 549       break;
 550   case KEYTYPE_DES3 :
 551       ret = wrap_des3 (minor_status, ctx, context, conf_req_flag,
 552                        qop_req, input_message_buffer, conf_state,
 553                        output_message_buffer, key);
 554       break;
 555   case KEYTYPE_ARCFOUR:
 556   case KEYTYPE_ARCFOUR_56:
 557       ret = _gssapi_wrap_arcfour (minor_status, ctx, context, conf_req_flag,
 558                                   qop_req, input_message_buffer, conf_state,
 559                                   output_message_buffer, key);
 560       break;
 561   default :
 562       ret = _gssapi_wrap_cfx (minor_status, ctx, context, conf_req_flag,
 563                               qop_req, input_message_buffer, conf_state,
 564                               output_message_buffer, key);
 565       break;
 566   }
 567   krb5_free_keyblock (context, key);
 568   return ret;
 569 }

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