lib/gssapi/get_mic.c

   1 /*
   2  * Copyright (c) 1997 - 2000 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 gss_get_mic
  39            (OM_uint32 * minor_status,
  40             const gss_ctx_id_t context_handle,
  41             gss_qop_t qop_req,
  42             const gss_buffer_t message_buffer,
  43             gss_buffer_t message_token
  44            )
  45 {
  46   u_char *p;
  47   MD5_CTX md5;
  48   u_char hash[16];
  49   des_key_schedule schedule;
  50   des_cblock key;
  51   des_cblock zero;
  52   int32_t seq_number;
  53   size_t len, total_len;
  54
  55   gssapi_krb5_encap_length (22, &len, &total_len);
  56
  57   message_token->length = total_len;
  58   message_token->value  = malloc (total_len);
  59   if (message_token->value == NULL)
  60     return GSS_S_FAILURE;
  61
  62   p = gssapi_krb5_make_header(message_token->value,
  63                               len,
  64                               "\x01\x01");
  65
  66   memcpy (p, "\x00\x00", 2);
  67   p += 2;
  68   memcpy (p, "\xff\xff\xff\xff", 4);
  69   p += 4;
  70
  71   /* Fill in later */
  72   memset (p, 0, 16);
  73   p += 16;
  74
  75   /* checksum */
  76   MD5Init (&md5);
  77   MD5Update (&md5, p - 24, 8);
  78   MD5Update (&md5, message_buffer->value,
  79              message_buffer->length);
  80   MD5Final (hash, &md5);
  81
  82   memset (&zero, 0, sizeof(zero));
  83   gss_krb5_getsomekey(context_handle, &key);
  84   des_set_key (&key, schedule);
  85   des_cbc_cksum ((const void *)hash, (void *)hash, sizeof(hash),
  86                  schedule, &zero);
  87   memcpy (p - 8, hash, 8);
  88
  89   /* sequence number */
  90   krb5_auth_getlocalseqnumber (gssapi_krb5_context,
  91                                context_handle->auth_context,
  92                                &seq_number);
  93
  94   p -= 16;
  95   p[0] = (seq_number >> 0)  & 0xFF;
  96   p[1] = (seq_number >> 8)  & 0xFF;
  97   p[2] = (seq_number >> 16) & 0xFF;
  98   p[3] = (seq_number >> 24) & 0xFF;
  99   memset (p + 4,
 100           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 101           4);
 102
 103   des_set_key (&key, schedule);
 104   des_cbc_encrypt ((const void *)p, (void *)p, 8,
 105                    schedule, (des_cblock *)(p + 8), DES_ENCRYPT);
 106
 107   krb5_auth_setlocalseqnumber (gssapi_krb5_context,
 108                                context_handle->auth_context,
 109                                ++seq_number);
 110
 111   memset (key, 0, sizeof(key));
 112   memset (schedule, 0, sizeof(schedule));
 113
 114   return GSS_S_COMPLETE;
 115 }