crypto/external/bsd/heimdal/dist/lib/gssapi/krb5/unwrap.c

   1 /*      $NetBSD: unwrap.c,v 1.1.1.2 2014/04/24 12:45:29 pettai Exp $    */
   2
   3 /*
   4  * Copyright (c) 1997 - 2004 Kungliga Tekniska Högskolan
   5  * (Royal Institute of Technology, Stockholm, Sweden).
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * 3. Neither the name of the Institute nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "gsskrb5_locl.h"
  37
  38 #ifdef HEIM_WEAK_CRYPTO
  39
  40 static OM_uint32
  41 unwrap_des
  42            (OM_uint32 * minor_status,
  43             const gsskrb5_ctx context_handle,
  44             const gss_buffer_t input_message_buffer,
  45             gss_buffer_t output_message_buffer,
  46             int * conf_state,
  47             gss_qop_t * qop_state,
  48             krb5_keyblock *key
  49            )
  50 {
  51   u_char *p, *seq;
  52   size_t len;
  53   EVP_MD_CTX *md5;
  54   u_char hash[16];
  55   EVP_CIPHER_CTX des_ctx;
  56   DES_key_schedule schedule;
  57   DES_cblock deskey;
  58   DES_cblock zero;
  59   size_t i;
  60   uint32_t seq_number;
  61   size_t padlength;
  62   OM_uint32 ret;
  63   int cstate;
  64   int cmp;
  65   int token_len;
  66
  67   if (IS_DCE_STYLE(context_handle)) {
  68      token_len = 22 + 8 + 15; /* 45 */
  69   } else {
  70      token_len = input_message_buffer->length;
  71   }
  72
  73   p = input_message_buffer->value;
  74   ret = _gsskrb5_verify_header (&p,
  75                                    token_len,
  76                                    "\x02\x01",
  77                                    GSS_KRB5_MECHANISM);
  78   if (ret)
  79       return ret;
  80
  81   if (memcmp (p, "\x00\x00", 2) != 0)
  82     return GSS_S_BAD_SIG;
  83   p += 2;
  84   if (memcmp (p, "\x00\x00", 2) == 0) {
  85       cstate = 1;
  86   } else if (memcmp (p, "\xFF\xFF", 2) == 0) {
  87       cstate = 0;
  88   } else
  89       return GSS_S_BAD_MIC;
  90   p += 2;
  91   if(conf_state != NULL)
  92       *conf_state = cstate;
  93   if (memcmp (p, "\xff\xff", 2) != 0)
  94     return GSS_S_DEFECTIVE_TOKEN;
  95   p += 2;
  96   p += 16;
  97
  98   len = p - (u_char *)input_message_buffer->value;
  99
 100   if(cstate) {
 101       /* decrypt data */
 102       memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 103       memset (&zero, 0, sizeof(zero));
 104
 105       for (i = 0; i < sizeof(deskey); ++i)
 106           deskey[i] ^= 0xf0;
 107
 108
 109       EVP_CIPHER_CTX_init(&des_ctx);
 110       EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, deskey, zero, 0);
 111       EVP_Cipher(&des_ctx, p, p, input_message_buffer->length - len);
 112       EVP_CIPHER_CTX_cleanup(&des_ctx);
 113
 114       memset (&schedule, 0, sizeof(schedule));
 115   }
 116
 117   if (IS_DCE_STYLE(context_handle)) {
 118     padlength = 0;
 119   } else {
 120     /* check pad */
 121     ret = _gssapi_verify_pad(input_message_buffer,
 122                              input_message_buffer->length - len,
 123                              &padlength);
 124     if (ret)
 125         return ret;
 126   }
 127
 128   md5 = EVP_MD_CTX_create();
 129   EVP_DigestInit_ex(md5, EVP_md5(), NULL);
 130   EVP_DigestUpdate(md5, p - 24, 8);
 131   EVP_DigestUpdate(md5, p, input_message_buffer->length - len);
 132   EVP_DigestFinal_ex(md5, hash, NULL);
 133   EVP_MD_CTX_destroy(md5);
 134
 135   memset (&zero, 0, sizeof(zero));
 136   memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
 137   DES_set_key_unchecked (&deskey, &schedule);
 138   DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
 139                  &schedule, &zero);
 140   if (ct_memcmp (p - 8, hash, 8) != 0)
 141     return GSS_S_BAD_MIC;
 142
 143   /* verify sequence number */
 144
 145   HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 146
 147   p -= 16;
 148
 149   EVP_CIPHER_CTX_init(&des_ctx);
 150   EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
 151   EVP_Cipher(&des_ctx, p, p, 8);
 152   EVP_CIPHER_CTX_cleanup(&des_ctx);
 153
 154   memset (deskey, 0, sizeof(deskey));
 155   memset (&schedule, 0, sizeof(schedule));
 156
 157   seq = p;
 158   _gsskrb5_decode_om_uint32(seq, &seq_number);
 159
 160   if (context_handle->more_flags & LOCAL)
 161       cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
 162   else
 163       cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
 164
 165   if (cmp != 0) {
 166     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 167     return GSS_S_BAD_MIC;
 168   }
 169
 170   ret = _gssapi_msg_order_check(context_handle->order, seq_number);
 171   if (ret) {
 172     HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 173     return ret;
 174   }
 175
 176   HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 177
 178   /* copy out data */
 179
 180   output_message_buffer->length = input_message_buffer->length
 181     - len - padlength - 8;
 182   output_message_buffer->value  = malloc(output_message_buffer->length);
 183   if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
 184       return GSS_S_FAILURE;
 185   memcpy (output_message_buffer->value,
 186           p + 24,
 187           output_message_buffer->length);
 188   return GSS_S_COMPLETE;
 189 }
 190 #endif
 191
 192 static OM_uint32
 193 unwrap_des3
 194            (OM_uint32 * minor_status,
 195             const gsskrb5_ctx context_handle,
 196             krb5_context context,
 197             const gss_buffer_t input_message_buffer,
 198             gss_buffer_t output_message_buffer,
 199             int * conf_state,
 200             gss_qop_t * qop_state,
 201             krb5_keyblock *key
 202            )
 203 {
 204   u_char *p;
 205   size_t len;
 206   u_char *seq;
 207   krb5_data seq_data;
 208   u_char cksum[20];
 209   uint32_t seq_number;
 210   size_t padlength;
 211   OM_uint32 ret;
 212   int cstate;
 213   krb5_crypto crypto;
 214   Checksum csum;
 215   int cmp;
 216   int token_len;
 217
 218   if (IS_DCE_STYLE(context_handle)) {
 219      token_len = 34 + 8 + 15; /* 57 */
 220   } else {
 221      token_len = input_message_buffer->length;
 222   }
 223
 224   p = input_message_buffer->value;
 225   ret = _gsskrb5_verify_header (&p,
 226                                    token_len,
 227                                    "\x02\x01",
 228                                    GSS_KRB5_MECHANISM);
 229   if (ret)
 230       return ret;
 231
 232   if (memcmp (p, "\x04\x00", 2) != 0) /* HMAC SHA1 DES3_KD */
 233     return GSS_S_BAD_SIG;
 234   p += 2;
 235   if (ct_memcmp (p, "\x02\x00", 2) == 0) {
 236     cstate = 1;
 237   } else if (ct_memcmp (p, "\xff\xff", 2) == 0) {
 238     cstate = 0;
 239   } else
 240     return GSS_S_BAD_MIC;
 241   p += 2;
 242   if(conf_state != NULL)
 243     *conf_state = cstate;
 244   if (ct_memcmp (p, "\xff\xff", 2) != 0)
 245     return GSS_S_DEFECTIVE_TOKEN;
 246   p += 2;
 247   p += 28;
 248
 249   len = p - (u_char *)input_message_buffer->value;
 250
 251   if(cstate) {
 252       /* decrypt data */
 253       krb5_data tmp;
 254
 255       ret = krb5_crypto_init(context, key,
 256                              ETYPE_DES3_CBC_NONE, &crypto);
 257       if (ret) {
 258           *minor_status = ret;
 259           return GSS_S_FAILURE;
 260       }
 261       ret = krb5_decrypt(context, crypto, KRB5_KU_USAGE_SEAL,
 262                          p, input_message_buffer->length - len, &tmp);
 263       krb5_crypto_destroy(context, crypto);
 264       if (ret) {
 265           *minor_status = ret;
 266           return GSS_S_FAILURE;
 267       }
 268       assert (tmp.length == input_message_buffer->length - len);
 269
 270       memcpy (p, tmp.data, tmp.length);
 271       krb5_data_free(&tmp);
 272   }
 273
 274   if (IS_DCE_STYLE(context_handle)) {
 275     padlength = 0;
 276   } else {
 277     /* check pad */
 278     ret = _gssapi_verify_pad(input_message_buffer,
 279                              input_message_buffer->length - len,
 280                              &padlength);
 281     if (ret)
 282         return ret;
 283   }
 284
 285   /* verify sequence number */
 286
 287   HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
 288
 289   p -= 28;
 290
 291   ret = krb5_crypto_init(context, key,
 292                          ETYPE_DES3_CBC_NONE, &crypto);
 293   if (ret) {
 294       *minor_status = ret;
 295       HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 296       return GSS_S_FAILURE;
 297   }
 298   {
 299       DES_cblock ivec;
 300
 301       memcpy(&ivec, p + 8, 8);
 302       ret = krb5_decrypt_ivec (context,
 303                                crypto,
 304                                KRB5_KU_USAGE_SEQ,
 305                                p, 8, &seq_data,
 306                                &ivec);
 307   }
 308   krb5_crypto_destroy (context, crypto);
 309   if (ret) {
 310       *minor_status = ret;
 311       HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 312       return GSS_S_FAILURE;
 313   }
 314   if (seq_data.length != 8) {
 315       krb5_data_free (&seq_data);
 316       *minor_status = 0;
 317       HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 318       return GSS_S_BAD_MIC;
 319   }
 320
 321   seq = seq_data.data;
 322   _gsskrb5_decode_om_uint32(seq, &seq_number);
 323
 324   if (context_handle->more_flags & LOCAL)
 325       cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
 326   else
 327       cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
 328
 329   krb5_data_free (&seq_data);
 330   if (cmp != 0) {
 331       *minor_status = 0;
 332       HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 333       return GSS_S_BAD_MIC;
 334   }
 335
 336   ret = _gssapi_msg_order_check(context_handle->order, seq_number);
 337   if (ret) {
 338       *minor_status = 0;
 339       HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 340       return ret;
 341   }
 342
 343   HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
 344
 345   /* verify checksum */
 346
 347   memcpy (cksum, p + 8, 20);
 348
 349   memcpy (p + 20, p - 8, 8);
 350
 351   csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
 352   csum.checksum.length = 20;
 353   csum.checksum.data   = cksum;
 354
 355   ret = krb5_crypto_init(context, key, 0, &crypto);
 356   if (ret) {
 357       *minor_status = ret;
 358       return GSS_S_FAILURE;
 359   }
 360
 361   ret = krb5_verify_checksum (context, crypto,
 362                               KRB5_KU_USAGE_SIGN,
 363                               p + 20,
 364                               input_message_buffer->length - len + 8,
 365                               &csum);
 366   krb5_crypto_destroy (context, crypto);
 367   if (ret) {
 368       *minor_status = ret;
 369       return GSS_S_FAILURE;
 370   }
 371
 372   /* copy out data */
 373
 374   output_message_buffer->length = input_message_buffer->length
 375     - len - padlength - 8;
 376   output_message_buffer->value  = malloc(output_message_buffer->length);
 377   if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
 378       return GSS_S_FAILURE;
 379   memcpy (output_message_buffer->value,
 380           p + 36,
 381           output_message_buffer->length);
 382   return GSS_S_COMPLETE;
 383 }
 384
 385 OM_uint32 GSSAPI_CALLCONV _gsskrb5_unwrap
 386            (OM_uint32 * minor_status,
 387             const gss_ctx_id_t context_handle,
 388             const gss_buffer_t input_message_buffer,
 389             gss_buffer_t output_message_buffer,
 390             int * conf_state,
 391             gss_qop_t * qop_state
 392            )
 393 {
 394   krb5_keyblock *key;
 395   krb5_context context;
 396   OM_uint32 ret;
 397   krb5_keytype keytype;
 398   gsskrb5_ctx ctx = (gsskrb5_ctx) context_handle;
 399
 400   output_message_buffer->value = NULL;
 401   output_message_buffer->length = 0;
 402   if (qop_state != NULL)
 403       *qop_state = GSS_C_QOP_DEFAULT;
 404
 405   GSSAPI_KRB5_INIT (&context);
 406
 407   if (ctx->more_flags & IS_CFX)
 408       return _gssapi_unwrap_cfx (minor_status, ctx, context,
 409                                  input_message_buffer, output_message_buffer,
 410                                  conf_state, qop_state);
 411
 412   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 413   ret = _gsskrb5i_get_token_key(ctx, context, &key);
 414   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 415   if (ret) {
 416       *minor_status = ret;
 417       return GSS_S_FAILURE;
 418   }
 419   krb5_enctype_to_keytype (context, key->keytype, &keytype);
 420
 421   *minor_status = 0;
 422
 423   switch (keytype) {
 424   case KEYTYPE_DES :
 425 #ifdef HEIM_WEAK_CRYPTO
 426       ret = unwrap_des (minor_status, ctx,
 427                         input_message_buffer, output_message_buffer,
 428                         conf_state, qop_state, key);
 429 #else
 430       ret = GSS_S_FAILURE;
 431 #endif
 432       break;
 433   case KEYTYPE_DES3 :
 434       ret = unwrap_des3 (minor_status, ctx, context,
 435                          input_message_buffer, output_message_buffer,
 436                          conf_state, qop_state, key);
 437       break;
 438   case KEYTYPE_ARCFOUR:
 439   case KEYTYPE_ARCFOUR_56:
 440       ret = _gssapi_unwrap_arcfour (minor_status, ctx, context,
 441                                     input_message_buffer, output_message_buffer,
 442                                     conf_state, qop_state, key);
 443       break;
 444   default :
 445       abort();
 446       break;
 447   }
 448   krb5_free_keyblock (context, key);
 449   return ret;
 450 }