lib/gssapi/krb5/get_mic.c

   1 /*
   2  * Copyright (c) 1997 - 2001 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 static OM_uint32
  39 mic_des
  40            (OM_uint32 * minor_status,
  41             const gss_ctx_id_t context_handle,
  42             gss_qop_t qop_req,
  43             const gss_buffer_t message_buffer,
  44             gss_buffer_t message_token,
  45             krb5_keyblock *key
  46            )
  47 {
  48   u_char *p;
  49   MD5_CTX md5;
  50   u_char hash[16];
  51   des_key_schedule schedule;
  52   des_cblock deskey;
  53   des_cblock zero;
  54   int32_t seq_number;
  55   size_t len, total_len;
  56
  57   gssapi_krb5_encap_length (22, &len, &total_len);
  58
  59   message_token->length = total_len;
  60   message_token->value  = malloc (total_len);
  61   if (message_token->value == NULL) {
  62     *minor_status = ENOMEM;
  63     return GSS_S_FAILURE;
  64   }
  65
  66   p = gssapi_krb5_make_header(message_token->value,
  67                               len,
  68                               "\x01\x01"); /* TOK_ID */
  69
  70   memcpy (p, "\x00\x00", 2);    /* SGN_ALG = DES MAC MD5 */
  71   p += 2;
  72
  73   memcpy (p, "\xff\xff\xff\xff", 4); /* Filler */
  74   p += 4;
  75
  76   /* Fill in later (SND-SEQ) */
  77   memset (p, 0, 16);
  78   p += 16;
  79
  80   /* checksum */
  81   MD5_Init (&md5);
  82   MD5_Update (&md5, p - 24, 8);
  83   MD5_Update (&md5, message_buffer->value, message_buffer->length);
  84   MD5_Final (hash, &md5);
  85
  86   memset (&zero, 0, sizeof(zero));
  87   memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
  88   des_set_key (&deskey, schedule);
  89   des_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
  90                  schedule, &zero);
  91   memcpy (p - 8, hash, 8);      /* SGN_CKSUM */
  92
  93   /* sequence number */
  94   krb5_auth_con_getlocalseqnumber (gssapi_krb5_context,
  95                                context_handle->auth_context,
  96                                &seq_number);
  97
  98   p -= 16;                      /* SND_SEQ */
  99   p[0] = (seq_number >> 0)  & 0xFF;
 100   p[1] = (seq_number >> 8)  & 0xFF;
 101   p[2] = (seq_number >> 16) & 0xFF;
 102   p[3] = (seq_number >> 24) & 0xFF;
 103   memset (p + 4,
 104           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 105           4);
 106
 107   des_set_key (&deskey, schedule);
 108   des_cbc_encrypt ((void *)p, (void *)p, 8,
 109                    schedule, (des_cblock *)(p + 8), DES_ENCRYPT);
 110
 111   krb5_auth_con_setlocalseqnumber (gssapi_krb5_context,
 112                                context_handle->auth_context,
 113                                ++seq_number);
 114
 115   memset (deskey, 0, sizeof(deskey));
 116   memset (schedule, 0, sizeof(schedule));
 117
 118   return GSS_S_COMPLETE;
 119 }
 120
 121 static OM_uint32
 122 mic_des3
 123            (OM_uint32 * minor_status,
 124             const gss_ctx_id_t context_handle,
 125             gss_qop_t qop_req,
 126             const gss_buffer_t message_buffer,
 127             gss_buffer_t message_token,
 128             krb5_keyblock *key
 129            )
 130 {
 131   u_char *p;
 132   Checksum cksum;
 133   u_char seq[8];
 134
 135   int32_t seq_number;
 136   size_t len, total_len;
 137
 138   krb5_crypto crypto;
 139   krb5_error_code kret;
 140   krb5_data encdata;
 141   char *tmp;
 142
 143   gssapi_krb5_encap_length (36, &len, &total_len);
 144
 145   message_token->length = total_len;
 146   message_token->value  = malloc (total_len);
 147   if (message_token->value == NULL) {
 148       *minor_status = ENOMEM;
 149       return GSS_S_FAILURE;
 150   }
 151
 152   p = gssapi_krb5_make_header(message_token->value,
 153                               len,
 154                               "\x01\x01"); /* TOK-ID */
 155
 156   memcpy (p, "\x04\x00", 2);    /* SGN_ALG = HMAC SHA1 DES3-KD */
 157   p += 2;
 158
 159   memcpy (p, "\xff\xff\xff\xff", 4); /* filler */
 160   p += 4;
 161
 162   /* this should be done in parts */
 163
 164   tmp = malloc (message_buffer->length + 8);
 165   if (tmp == NULL) {
 166       free (message_token->value);
 167       *minor_status = ENOMEM;
 168       return GSS_S_FAILURE;
 169   }
 170   memcpy (tmp, p - 8, 8);
 171   memcpy (tmp + 8, message_buffer->value, message_buffer->length);
 172
 173   kret = krb5_crypto_init(gssapi_krb5_context, key, 0, &crypto);
 174   if (kret) {
 175       free (message_token->value);
 176       free (tmp);
 177       gssapi_krb5_set_error_string ();
 178       *minor_status = kret;
 179       return GSS_S_FAILURE;
 180   }
 181
 182   kret = krb5_create_checksum (gssapi_krb5_context,
 183                                crypto,
 184                                KRB5_KU_USAGE_SIGN,
 185                                0,
 186                                tmp,
 187                                message_buffer->length + 8,
 188                                &cksum);
 189   free (tmp);
 190   krb5_crypto_destroy (gssapi_krb5_context, crypto);
 191   if (kret) {
 192       free (message_token->value);
 193       gssapi_krb5_set_error_string ();
 194       *minor_status = kret;
 195       return GSS_S_FAILURE;
 196   }
 197
 198   memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
 199
 200   /* sequence number */
 201   krb5_auth_con_getlocalseqnumber (gssapi_krb5_context,
 202                                context_handle->auth_context,
 203                                &seq_number);
 204
 205   seq[0] = (seq_number >> 0)  & 0xFF;
 206   seq[1] = (seq_number >> 8)  & 0xFF;
 207   seq[2] = (seq_number >> 16) & 0xFF;
 208   seq[3] = (seq_number >> 24) & 0xFF;
 209   memset (seq + 4,
 210           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 211           4);
 212
 213   kret = krb5_crypto_init(gssapi_krb5_context, key,
 214                           ETYPE_DES3_CBC_NONE, &crypto);
 215   if (kret) {
 216       free (message_token->value);
 217       gssapi_krb5_set_error_string ();
 218       *minor_status = kret;
 219       return GSS_S_FAILURE;
 220   }
 221
 222   kret = krb5_encrypt (gssapi_krb5_context,
 223                        crypto,
 224                        KRB5_KU_USAGE_SEQ,
 225                        seq, 8, &encdata);
 226   krb5_crypto_destroy (gssapi_krb5_context, crypto);
 227   if (kret) {
 228       free (message_token->value);
 229       gssapi_krb5_set_error_string ();
 230       *minor_status = kret;
 231       return GSS_S_FAILURE;
 232   }
 233
 234   assert (encdata.length == 8);
 235
 236   memcpy (p, encdata.data, encdata.length);
 237   krb5_data_free (&encdata);
 238
 239   p += 8 + cksum.checksum.length;
 240
 241   memcpy (p, message_buffer->value, message_buffer->length);
 242
 243   krb5_auth_con_setlocalseqnumber (gssapi_krb5_context,
 244                                context_handle->auth_context,
 245                                ++seq_number);
 246
 247   free_Checksum (&cksum);
 248   return GSS_S_COMPLETE;
 249 }
 250
 251 OM_uint32 gss_get_mic
 252            (OM_uint32 * minor_status,
 253             const gss_ctx_id_t context_handle,
 254             gss_qop_t qop_req,
 255             const gss_buffer_t message_buffer,
 256             gss_buffer_t message_token
 257            )
 258 {
 259   krb5_keyblock *key;
 260   OM_uint32 ret;
 261   krb5_keytype keytype;
 262
 263   ret = gss_krb5_get_localkey(context_handle, &key);
 264   if (ret) {
 265       gssapi_krb5_set_error_string ();
 266       *minor_status = ret;
 267       return GSS_S_FAILURE;
 268   }
 269   krb5_enctype_to_keytype (gssapi_krb5_context, key->keytype, &keytype);
 270
 271   switch (keytype) {
 272   case KEYTYPE_DES :
 273       ret = mic_des (minor_status, context_handle, qop_req,
 274                      message_buffer, message_token, key);
 275       break;
 276   case KEYTYPE_DES3 :
 277       ret = mic_des3 (minor_status, context_handle, qop_req,
 278                       message_buffer, message_token, key);
 279       break;
 280   default :
 281       *minor_status = KRB5_PROG_ETYPE_NOSUPP;
 282       ret = GSS_S_FAILURE;
 283       break;
 284   }
 285   krb5_free_keyblock (gssapi_krb5_context, key);
 286   return ret;
 287 }