lib/gssapi/krb5/get_mic.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 "gsskrb5_locl.h"
  35
  36 #ifdef HEIM_WEAK_CRYPTO
  37
  38 static OM_uint32
  39 mic_des
  40            (OM_uint32 * minor_status,
  41             const gsskrb5_ctx ctx,
  42             krb5_context context,
  43             gss_qop_t qop_req,
  44             const gss_buffer_t message_buffer,
  45             gss_buffer_t message_token,
  46             krb5_keyblock *key
  47            )
  48 {
  49   u_char *p;
  50   EVP_MD_CTX *md5;
  51   u_char hash[16];
  52   DES_key_schedule schedule;
  53   EVP_CIPHER_CTX des_ctx;
  54   DES_cblock deskey;
  55   DES_cblock zero;
  56   int32_t seq_number;
  57   size_t len, total_len;
  58
  59   _gsskrb5_encap_length (22, &len, &total_len, GSS_KRB5_MECHANISM);
  60
  61   message_token->length = total_len;
  62   message_token->value  = malloc (total_len);
  63   if (message_token->value == NULL) {
  64     message_token->length = 0;
  65     *minor_status = ENOMEM;
  66     return GSS_S_FAILURE;
  67   }
  68
  69   p = _gsskrb5_make_header(message_token->value,
  70                               len,
  71                               "\x01\x01", /* TOK_ID */
  72                               GSS_KRB5_MECHANISM);
  73
  74   memcpy (p, "\x00\x00", 2);    /* SGN_ALG = DES MAC MD5 */
  75   p += 2;
  76
  77   memcpy (p, "\xff\xff\xff\xff", 4); /* Filler */
  78   p += 4;
  79
  80   /* Fill in later (SND-SEQ) */
  81   memset (p, 0, 16);
  82   p += 16;
  83
  84   /* checksum */
  85   md5 = EVP_MD_CTX_create();
  86   EVP_DigestInit_ex(md5, EVP_md5(), NULL);
  87   EVP_DigestUpdate(md5, p - 24, 8);
  88   EVP_DigestUpdate(md5, message_buffer->value, message_buffer->length);
  89   EVP_DigestFinal_ex(md5, hash, NULL);
  90   EVP_MD_CTX_destroy(md5);
  91
  92   memset (&zero, 0, sizeof(zero));
  93   memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
  94   DES_set_key_unchecked (&deskey, &schedule);
  95   DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
  96                  &schedule, &zero);
  97   memcpy (p - 8, hash, 8);      /* SGN_CKSUM */
  98
  99   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 100   /* sequence number */
 101   krb5_auth_con_getlocalseqnumber (context,
 102                                    ctx->auth_context,
 103                                    &seq_number);
 104
 105   p -= 16;                      /* SND_SEQ */
 106   p[0] = (seq_number >> 0)  & 0xFF;
 107   p[1] = (seq_number >> 8)  & 0xFF;
 108   p[2] = (seq_number >> 16) & 0xFF;
 109   p[3] = (seq_number >> 24) & 0xFF;
 110   memset (p + 4,
 111           (ctx->more_flags & LOCAL) ? 0 : 0xFF,
 112           4);
 113
 114   EVP_CIPHER_CTX_init(&des_ctx);
 115   EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, p + 8, 1);
 116   EVP_Cipher(&des_ctx, p, p, 8);
 117   EVP_CIPHER_CTX_cleanup(&des_ctx);
 118
 119   krb5_auth_con_setlocalseqnumber (context,
 120                                ctx->auth_context,
 121                                ++seq_number);
 122   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 123
 124   memset (deskey, 0, sizeof(deskey));
 125   memset (&schedule, 0, sizeof(schedule));
 126
 127   *minor_status = 0;
 128   return GSS_S_COMPLETE;
 129 }
 130 #endif
 131
 132 static OM_uint32
 133 mic_des3
 134            (OM_uint32 * minor_status,
 135             const gsskrb5_ctx ctx,
 136             krb5_context context,
 137             gss_qop_t qop_req,
 138             const gss_buffer_t message_buffer,
 139             gss_buffer_t message_token,
 140             krb5_keyblock *key
 141            )
 142 {
 143   u_char *p;
 144   Checksum cksum;
 145   u_char seq[8];
 146
 147   int32_t seq_number;
 148   size_t len, total_len;
 149
 150   krb5_crypto crypto;
 151   krb5_error_code kret;
 152   krb5_data encdata;
 153   char *tmp;
 154   char ivec[8];
 155
 156   _gsskrb5_encap_length (36, &len, &total_len, GSS_KRB5_MECHANISM);
 157
 158   message_token->length = total_len;
 159   message_token->value  = malloc (total_len);
 160   if (message_token->value == NULL) {
 161       message_token->length = 0;
 162       *minor_status = ENOMEM;
 163       return GSS_S_FAILURE;
 164   }
 165
 166   p = _gsskrb5_make_header(message_token->value,
 167                               len,
 168                               "\x01\x01", /* TOK-ID */
 169                               GSS_KRB5_MECHANISM);
 170
 171   memcpy (p, "\x04\x00", 2);    /* SGN_ALG = HMAC SHA1 DES3-KD */
 172   p += 2;
 173
 174   memcpy (p, "\xff\xff\xff\xff", 4); /* filler */
 175   p += 4;
 176
 177   /* this should be done in parts */
 178
 179   tmp = malloc (message_buffer->length + 8);
 180   if (tmp == NULL) {
 181       free (message_token->value);
 182       message_token->value = NULL;
 183       message_token->length = 0;
 184       *minor_status = ENOMEM;
 185       return GSS_S_FAILURE;
 186   }
 187   memcpy (tmp, p - 8, 8);
 188   memcpy (tmp + 8, message_buffer->value, message_buffer->length);
 189
 190   kret = krb5_crypto_init(context, key, 0, &crypto);
 191   if (kret) {
 192       free (message_token->value);
 193       message_token->value = NULL;
 194       message_token->length = 0;
 195       free (tmp);
 196       *minor_status = kret;
 197       return GSS_S_FAILURE;
 198   }
 199
 200   kret = krb5_create_checksum (context,
 201                                crypto,
 202                                KRB5_KU_USAGE_SIGN,
 203                                0,
 204                                tmp,
 205                                message_buffer->length + 8,
 206                                &cksum);
 207   free (tmp);
 208   krb5_crypto_destroy (context, crypto);
 209   if (kret) {
 210       free (message_token->value);
 211       message_token->value = NULL;
 212       message_token->length = 0;
 213       *minor_status = kret;
 214       return GSS_S_FAILURE;
 215   }
 216
 217   memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
 218
 219   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 220   /* sequence number */
 221   krb5_auth_con_getlocalseqnumber (context,
 222                                ctx->auth_context,
 223                                &seq_number);
 224
 225   seq[0] = (seq_number >> 0)  & 0xFF;
 226   seq[1] = (seq_number >> 8)  & 0xFF;
 227   seq[2] = (seq_number >> 16) & 0xFF;
 228   seq[3] = (seq_number >> 24) & 0xFF;
 229   memset (seq + 4,
 230           (ctx->more_flags & LOCAL) ? 0 : 0xFF,
 231           4);
 232
 233   kret = krb5_crypto_init(context, key,
 234                           ETYPE_DES3_CBC_NONE, &crypto);
 235   if (kret) {
 236       free (message_token->value);
 237       message_token->value = NULL;
 238       message_token->length = 0;
 239       *minor_status = kret;
 240       return GSS_S_FAILURE;
 241   }
 242
 243   if (ctx->more_flags & COMPAT_OLD_DES3)
 244       memset(ivec, 0, 8);
 245   else
 246       memcpy(ivec, p + 8, 8);
 247
 248   kret = krb5_encrypt_ivec (context,
 249                             crypto,
 250                             KRB5_KU_USAGE_SEQ,
 251                             seq, 8, &encdata, ivec);
 252   krb5_crypto_destroy (context, crypto);
 253   if (kret) {
 254       free (message_token->value);
 255       message_token->value = NULL;
 256       message_token->length = 0;
 257       *minor_status = kret;
 258       return GSS_S_FAILURE;
 259   }
 260
 261   assert (encdata.length == 8);
 262
 263   memcpy (p, encdata.data, encdata.length);
 264   krb5_data_free (&encdata);
 265
 266   krb5_auth_con_setlocalseqnumber (context,
 267                                ctx->auth_context,
 268                                ++seq_number);
 269   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 270
 271   free_Checksum (&cksum);
 272   *minor_status = 0;
 273   return GSS_S_COMPLETE;
 274 }
 275
 276 OM_uint32 GSSAPI_CALLCONV _gsskrb5_get_mic
 277            (OM_uint32 * minor_status,
 278             gss_const_ctx_id_t context_handle,
 279             gss_qop_t qop_req,
 280             const gss_buffer_t message_buffer,
 281             gss_buffer_t message_token
 282            )
 283 {
 284   krb5_context context;
 285   const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
 286   krb5_keyblock *key;
 287   OM_uint32 ret;
 288
 289   GSSAPI_KRB5_INIT (&context);
 290
 291   if (ctx->more_flags & IS_CFX)
 292       return _gssapi_mic_cfx (minor_status, ctx, context, qop_req,
 293                               message_buffer, message_token);
 294
 295   HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
 296   ret = _gsskrb5i_get_token_key(ctx, context, &key);
 297   HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
 298   if (ret) {
 299       *minor_status = ret;
 300       return GSS_S_FAILURE;
 301   }
 302
 303   switch (key->keytype) {
 304   case KRB5_ENCTYPE_DES_CBC_CRC :
 305   case KRB5_ENCTYPE_DES_CBC_MD4 :
 306   case KRB5_ENCTYPE_DES_CBC_MD5 :
 307 #ifdef HEIM_WEAK_CRYPTO
 308       ret = mic_des (minor_status, ctx, context, qop_req,
 309                      message_buffer, message_token, key);
 310 #else
 311       ret = GSS_S_FAILURE;
 312 #endif
 313       break;
 314   case KRB5_ENCTYPE_DES3_CBC_MD5 :
 315   case KRB5_ENCTYPE_DES3_CBC_SHA1 :
 316       ret = mic_des3 (minor_status, ctx, context, qop_req,
 317                       message_buffer, message_token, key);
 318       break;
 319   case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5:
 320   case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56:
 321       ret = _gssapi_get_mic_arcfour (minor_status, ctx, context, qop_req,
 322                                      message_buffer, message_token, key);
 323       break;
 324   default :
 325       abort();
 326       break;
 327   }
 328   krb5_free_keyblock (context, key);
 329   return ret;
 330 }