lib/gssapi/wrap.c

   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 "gssapi_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 OM_uint32
  39 gss_krb5_get_localkey(const gss_ctx_id_t context_handle,
  40                        krb5_keyblock **key)
  41 {
  42     krb5_keyblock *skey;
  43
  44     krb5_auth_con_getlocalsubkey(gssapi_krb5_context,
  45                                  context_handle->auth_context,
  46                                  &skey);
  47     if(skey == NULL)
  48         krb5_auth_con_getremotesubkey(gssapi_krb5_context,
  49                                       context_handle->auth_context,
  50                                       &skey);
  51     if(skey == NULL)
  52         krb5_auth_con_getkey(gssapi_krb5_context,
  53                              context_handle->auth_context,
  54                              &skey);
  55     if(skey == NULL)
  56         return GSS_S_FAILURE;
  57     *key = skey;
  58     return 0;
  59 }
  60
  61 static OM_uint32
  62 sub_wrap_size (
  63             OM_uint32 req_output_size,
  64             OM_uint32 * max_input_size,
  65             int blocksize,
  66             int extrasize
  67            )
  68 {
  69   size_t len, total_len, padlength;
  70   padlength = blocksize - (req_output_size % blocksize);
  71   len = req_output_size + 8 + padlength + extrasize;
  72   gssapi_krb5_encap_length(len, &len, &total_len);
  73   *max_input_size = (OM_uint32)total_len;
  74   return GSS_S_COMPLETE;
  75 }
  76
  77 OM_uint32
  78 gss_wrap_size_limit (
  79             OM_uint32 * minor_status,
  80             const gss_ctx_id_t context_handle,
  81             int conf_req_flag,
  82             gss_qop_t qop_req,
  83             OM_uint32 req_output_size,
  84             OM_uint32 * max_input_size
  85            )
  86 {
  87   krb5_keyblock *key;
  88   OM_uint32 ret;
  89   krb5_keytype keytype;
  90
  91   ret = gss_krb5_get_localkey(context_handle, &key);
  92   if (ret) {
  93       gssapi_krb5_set_error_string ();
  94       *minor_status = ret;
  95       return GSS_S_FAILURE;
  96   }
  97   krb5_enctype_to_keytype (gssapi_krb5_context, key->keytype, &keytype);
  98
  99   switch (keytype) {
 100   case KEYTYPE_DES :
 101   case KEYTYPE_ARCFOUR:
 102       ret = sub_wrap_size(req_output_size, max_input_size, 8, 22);
 103       break;
 104   case KEYTYPE_DES3 :
 105       ret = sub_wrap_size(req_output_size, max_input_size, 8, 34);
 106       break;
 107   default :
 108       *minor_status = KRB5_PROG_ETYPE_NOSUPP;
 109       ret = GSS_S_FAILURE;
 110       break;
 111   }
 112   krb5_free_keyblock (gssapi_krb5_context, key);
 113   *minor_status = 0;
 114   return ret;
 115 }
 116
 117 static OM_uint32
 118 wrap_des
 119            (OM_uint32 * minor_status,
 120             const gss_ctx_id_t context_handle,
 121             int conf_req_flag,
 122             gss_qop_t qop_req,
 123             const gss_buffer_t input_message_buffer,
 124             int * conf_state,
 125             gss_buffer_t output_message_buffer,
 126             krb5_keyblock *key
 127            )
 128 {
 129   u_char *p;
 130   MD5_CTX md5;
 131   u_char hash[16];
 132   des_key_schedule schedule;
 133   des_cblock deskey;
 134   des_cblock zero;
 135   int i;
 136   int32_t seq_number;
 137   size_t len, total_len, padlength, datalen;
 138
 139   padlength = 8 - (input_message_buffer->length % 8);
 140   datalen = input_message_buffer->length + padlength + 8;
 141   len = datalen + 22;
 142   gssapi_krb5_encap_length (len, &len, &total_len);
 143
 144   output_message_buffer->length = total_len;
 145   output_message_buffer->value  = malloc (total_len);
 146   if (output_message_buffer->value == NULL) {
 147     *minor_status = ENOMEM;
 148     return GSS_S_FAILURE;
 149   }
 150
 151   p = gssapi_krb5_make_header(output_message_buffer->value,
 152                               len,
 153                               "\x02\x01"); /* TOK_ID */
 154
 155   /* SGN_ALG */
 156   memcpy (p, "\x00\x00", 2);
 157   p += 2;
 158   /* SEAL_ALG */
 159   if(conf_req_flag)
 160       memcpy (p, "\x00\x00", 2);
 161   else
 162       memcpy (p, "\xff\xff", 2);
 163   p += 2;
 164   /* Filler */
 165   memcpy (p, "\xff\xff", 2);
 166   p += 2;
 167
 168   /* fill in later */
 169   memset (p, 0, 16);
 170   p += 16;
 171
 172   /* confounder + data + pad */
 173   krb5_generate_random_block(p, 8);
 174   memcpy (p + 8, input_message_buffer->value,
 175           input_message_buffer->length);
 176   memset (p + 8 + input_message_buffer->length, padlength, padlength);
 177
 178   /* checksum */
 179   MD5_Init (&md5);
 180   MD5_Update (&md5, p - 24, 8);
 181   MD5_Update (&md5, p, datalen);
 182   MD5_Final (hash, &md5);
 183
 184   memset (&zero, 0, sizeof(zero));
 185   memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 186   des_set_key (&deskey, schedule);
 187   des_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
 188                  schedule, &zero);
 189   memcpy (p - 8, hash, 8);
 190
 191   /* sequence number */
 192   krb5_auth_con_getlocalseqnumber (gssapi_krb5_context,
 193                                context_handle->auth_context,
 194                                &seq_number);
 195
 196   p -= 16;
 197   p[0] = (seq_number >> 0)  & 0xFF;
 198   p[1] = (seq_number >> 8)  & 0xFF;
 199   p[2] = (seq_number >> 16) & 0xFF;
 200   p[3] = (seq_number >> 24) & 0xFF;
 201   memset (p + 4,
 202           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 203           4);
 204
 205   des_set_key (&deskey, schedule);
 206   des_cbc_encrypt ((void *)p, (void *)p, 8,
 207                    schedule, (des_cblock *)(p + 8), DES_ENCRYPT);
 208
 209   krb5_auth_con_setlocalseqnumber (gssapi_krb5_context,
 210                                context_handle->auth_context,
 211                                ++seq_number);
 212
 213   /* encrypt the data */
 214   p += 16;
 215
 216   if(conf_req_flag) {
 217       memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 218
 219       for (i = 0; i < sizeof(deskey); ++i)
 220           deskey[i] ^= 0xf0;
 221       des_set_key (&deskey, schedule);
 222       memset (&zero, 0, sizeof(zero));
 223       des_cbc_encrypt ((void *)p,
 224                        (void *)p,
 225                        datalen,
 226                        schedule,
 227                        &zero,
 228                        DES_ENCRYPT);
 229
 230       memset (deskey, 0, sizeof(deskey));
 231       memset (schedule, 0, sizeof(schedule));
 232   }
 233   if(conf_state != NULL)
 234       *conf_state = conf_req_flag;
 235   *minor_status = 0;
 236   return GSS_S_COMPLETE;
 237 }
 238
 239 static OM_uint32
 240 wrap_des3
 241            (OM_uint32 * minor_status,
 242             const gss_ctx_id_t context_handle,
 243             int conf_req_flag,
 244             gss_qop_t qop_req,
 245             const gss_buffer_t input_message_buffer,
 246             int * conf_state,
 247             gss_buffer_t output_message_buffer,
 248             krb5_keyblock *key
 249            )
 250 {
 251   u_char *p;
 252   u_char seq[8];
 253   int32_t seq_number;
 254   size_t len, total_len, padlength, datalen;
 255   u_int32_t ret;
 256   krb5_crypto crypto;
 257   Checksum cksum;
 258   krb5_data encdata;
 259
 260   padlength = 8 - (input_message_buffer->length % 8);
 261   datalen = input_message_buffer->length + padlength + 8;
 262   len = datalen + 34;
 263   gssapi_krb5_encap_length (len, &len, &total_len);
 264
 265   output_message_buffer->length = total_len;
 266   output_message_buffer->value  = malloc (total_len);
 267   if (output_message_buffer->value == NULL) {
 268     *minor_status = ENOMEM;
 269     return GSS_S_FAILURE;
 270   }
 271
 272   p = gssapi_krb5_make_header(output_message_buffer->value,
 273                               len,
 274                               "\x02\x01"); /* TOK_ID */
 275
 276   /* SGN_ALG */
 277   memcpy (p, "\x04\x00", 2);    /* HMAC SHA1 DES3-KD */
 278   p += 2;
 279   /* SEAL_ALG */
 280   if(conf_req_flag)
 281       memcpy (p, "\x02\x00", 2); /* DES3-KD */
 282   else
 283       memcpy (p, "\xff\xff", 2);
 284   p += 2;
 285   /* Filler */
 286   memcpy (p, "\xff\xff", 2);
 287   p += 2;
 288
 289   /* calculate checksum (the above + confounder + data + pad) */
 290
 291   memcpy (p + 20, p - 8, 8);
 292   krb5_generate_random_block(p + 28, 8);
 293   memcpy (p + 28 + 8, input_message_buffer->value,
 294           input_message_buffer->length);
 295   memset (p + 28 + 8 + input_message_buffer->length, padlength, padlength);
 296
 297   ret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto);
 298   if (ret) {
 299       gssapi_krb5_set_error_string ();
 300       free (output_message_buffer->value);
 301       *minor_status = ret;
 302       return GSS_S_FAILURE;
 303   }
 304
 305   ret = krb5_create_checksum (gssapi_krb5_context,
 306                               crypto,
 307                               KRB5_KU_USAGE_SIGN,
 308                               0,
 309                               p + 20,
 310                               datalen + 8,
 311                               &cksum);
 312   krb5_crypto_destroy (gssapi_krb5_context, crypto);
 313   if (ret) {
 314       gssapi_krb5_set_error_string ();
 315       free (output_message_buffer->value);
 316       *minor_status = ret;
 317       return GSS_S_FAILURE;
 318   }
 319
 320   /* zero out SND_SEQ + SGN_CKSUM in case */
 321   memset (p, 0, 28);
 322
 323   memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
 324   free_Checksum (&cksum);
 325
 326   /* sequence number */
 327   krb5_auth_con_getlocalseqnumber (gssapi_krb5_context,
 328                                context_handle->auth_context,
 329                                &seq_number);
 330
 331   seq[0] = (seq_number >> 0)  & 0xFF;
 332   seq[1] = (seq_number >> 8)  & 0xFF;
 333   seq[2] = (seq_number >> 16) & 0xFF;
 334   seq[3] = (seq_number >> 24) & 0xFF;
 335   memset (seq + 4,
 336           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 337           4);
 338
 339
 340   ret = krb5_crypto_init(gssapi_krb5_context, key, ETYPE_DES3_CBC_NONE,
 341                          &crypto);
 342   if (ret) {
 343       free (output_message_buffer->value);
 344       *minor_status = ret;
 345       return GSS_S_FAILURE;
 346   }
 347
 348   {
 349       des_cblock ivec;
 350
 351       memcpy (&ivec, p + 8, 8);
 352       ret = krb5_encrypt_ivec (gssapi_krb5_context,
 353                                crypto,
 354                                KRB5_KU_USAGE_SEQ,
 355                                seq, 8, &encdata,
 356                                &ivec);
 357   }
 358   krb5_crypto_destroy (gssapi_krb5_context, crypto);
 359   if (ret) {
 360       gssapi_krb5_set_error_string ();
 361       free (output_message_buffer->value);
 362       *minor_status = ret;
 363       return GSS_S_FAILURE;
 364   }
 365
 366   assert (encdata.length == 8);
 367
 368   memcpy (p, encdata.data, encdata.length);
 369   krb5_data_free (&encdata);
 370
 371   krb5_auth_con_setlocalseqnumber (gssapi_krb5_context,
 372                                context_handle->auth_context,
 373                                ++seq_number);
 374
 375   /* encrypt the data */
 376   p += 28;
 377
 378   if(conf_req_flag) {
 379       krb5_data tmp;
 380
 381       ret = krb5_crypto_init(gssapi_krb5_context, key,
 382                              ETYPE_DES3_CBC_NONE, &crypto);
 383       if (ret) {
 384           gssapi_krb5_set_error_string ();
 385           free (output_message_buffer->value);
 386           *minor_status = ret;
 387           return GSS_S_FAILURE;
 388       }
 389       ret = krb5_encrypt(gssapi_krb5_context, crypto, KRB5_KU_USAGE_SEAL,
 390                          p, datalen, &tmp);
 391       krb5_crypto_destroy(gssapi_krb5_context, crypto);
 392       if (ret) {
 393           gssapi_krb5_set_error_string ();
 394           free (output_message_buffer->value);
 395           *minor_status = ret;
 396           return GSS_S_FAILURE;
 397       }
 398       assert (tmp.length == datalen);
 399
 400       memcpy (p, tmp.data, datalen);
 401       krb5_data_free(&tmp);
 402   }
 403   if(conf_state != NULL)
 404       *conf_state = conf_req_flag;
 405   *minor_status = 0;
 406   return GSS_S_COMPLETE;
 407 }
 408
 409 OM_uint32 gss_wrap
 410            (OM_uint32 * minor_status,
 411             const gss_ctx_id_t context_handle,
 412             int conf_req_flag,
 413             gss_qop_t qop_req,
 414             const gss_buffer_t input_message_buffer,
 415             int * conf_state,
 416             gss_buffer_t output_message_buffer
 417            )
 418 {
 419   krb5_keyblock *key;
 420   OM_uint32 ret;
 421   krb5_keytype keytype;
 422
 423   ret = gss_krb5_get_localkey(context_handle, &key);
 424   if (ret) {
 425       gssapi_krb5_set_error_string ();
 426       *minor_status = ret;
 427       return GSS_S_FAILURE;
 428   }
 429   krb5_enctype_to_keytype (gssapi_krb5_context, key->keytype, &keytype);
 430
 431   switch (keytype) {
 432   case KEYTYPE_DES :
 433       ret = wrap_des (minor_status, context_handle, conf_req_flag,
 434                       qop_req, input_message_buffer, conf_state,
 435                       output_message_buffer, key);
 436       break;
 437   case KEYTYPE_DES3 :
 438       ret = wrap_des3 (minor_status, context_handle, conf_req_flag,
 439                        qop_req, input_message_buffer, conf_state,
 440                        output_message_buffer, key);
 441       break;
 442   case KEYTYPE_ARCFOUR:
 443       ret = _gssapi_wrap_arcfour (minor_status, context_handle, conf_req_flag,
 444                                   qop_req, input_message_buffer, conf_state,
 445                                   output_message_buffer, key);
 446       break;
 447   default :
 448       *minor_status = KRB5_PROG_ETYPE_NOSUPP;
 449       ret = GSS_S_FAILURE;
 450       break;
 451   }
 452   krb5_free_keyblock (gssapi_krb5_context, key);
 453   return ret;
 454 }