lib/gssapi/krb5/wrap.c

   1 /*
   2  * Copyright (c) 1997, 1998 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. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by Kungliga Tekniska
  20  *      Högskolan and its contributors.
  21  *
  22  * 4. Neither the name of the Institute nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include "gssapi_locl.h"
  40
  41 RCSID("$Id$");
  42
  43 OM_uint32 gss_wrap_size_limit (
  44             OM_uint32 * minor_status,
  45             const gss_ctx_id_t context_handle,
  46             int conf_req_flag,
  47             gss_qop_t qop_req,
  48             OM_uint32 req_output_size,
  49             OM_uint32 * max_input_size
  50            )
  51 {
  52   size_t len, total_len, padlength;
  53   padlength = 8 - (req_output_size % 8);
  54   len = req_output_size + 8 + padlength + 22;
  55   gssapi_krb5_encap_length(len, &len, &total_len);
  56   *max_input_size = (OM_uint32)total_len;
  57   return GSS_S_COMPLETE;
  58 }
  59
  60 OM_uint32 gss_wrap
  61            (OM_uint32 * minor_status,
  62             const gss_ctx_id_t context_handle,
  63             int conf_req_flag,
  64             gss_qop_t qop_req,
  65             const gss_buffer_t input_message_buffer,
  66             int * conf_state,
  67             gss_buffer_t output_message_buffer
  68            )
  69 {
  70   u_char *p;
  71   struct md5 md5;
  72   u_char hash[16];
  73   des_key_schedule schedule;
  74   des_cblock key;
  75   des_cblock zero;
  76   int i;
  77   int32_t seq_number;
  78   size_t len, total_len, padlength;
  79
  80   padlength = 8 - (input_message_buffer->length % 8);
  81   len = input_message_buffer->length + 8 + padlength + 22;
  82   gssapi_krb5_encap_length (len, &len, &total_len);
  83
  84   output_message_buffer->length = total_len;
  85   output_message_buffer->value  = malloc (total_len);
  86   if (output_message_buffer->value == NULL)
  87     return GSS_S_FAILURE;
  88
  89   p = gssapi_krb5_make_header(output_message_buffer->value,
  90                               len,
  91                               "\x02\x01");
  92
  93
  94   /* SGN_ALG */
  95   memcpy (p, "\x00\x00", 2);
  96   p += 2;
  97   /* SEAL_ALG */
  98   if(conf_req_flag)
  99       memcpy (p, "\x00\x00", 2);
 100   else
 101       memcpy (p, "\xff\xff", 2);
 102   p += 2;
 103   /* Filler */
 104   memcpy (p, "\xff\xff", 2);
 105   p += 2;
 106
 107   /* fill in later */
 108   memset (p, 0, 16);
 109   p += 16;
 110
 111   /* confounder + data + pad */
 112   des_new_random_key((des_cblock*)p);
 113   memcpy (p + 8, input_message_buffer->value,
 114           input_message_buffer->length);
 115   memset (p + 8 + input_message_buffer->length, padlength, padlength);
 116
 117   /* checksum */
 118   md5_init (&md5);
 119   md5_update (&md5, p - 24, 8);
 120   md5_update (&md5, p, input_message_buffer->length + padlength + 8);
 121   md5_finito (&md5, hash);
 122
 123   memset (&zero, 0, sizeof(zero));
 124   gss_krb5_getsomekey(context_handle, &key);
 125   des_set_key (&key, schedule);
 126   des_cbc_cksum ((des_cblock *)hash,
 127                  (des_cblock *)hash, sizeof(hash), schedule, &zero);
 128   memcpy (p - 8, hash, 8);
 129
 130   /* sequence number */
 131   krb5_auth_getlocalseqnumber (gssapi_krb5_context,
 132                                context_handle->auth_context,
 133                                &seq_number);
 134
 135   p -= 16;
 136   p[0] = (seq_number >> 0)  & 0xFF;
 137   p[1] = (seq_number >> 8)  & 0xFF;
 138   p[2] = (seq_number >> 16) & 0xFF;
 139   p[3] = (seq_number >> 24) & 0xFF;
 140   memset (p + 4,
 141           (context_handle->more_flags & LOCAL) ? 0 : 0xFF,
 142           4);
 143
 144   des_set_key (&key, schedule);
 145   des_cbc_encrypt ((des_cblock *)p, (des_cblock *)p, 8,
 146                    schedule, (des_cblock *)(p + 8), DES_ENCRYPT);
 147
 148   krb5_auth_setlocalseqnumber (gssapi_krb5_context,
 149                                context_handle->auth_context,
 150                                ++seq_number);
 151
 152   /* encrypt the data */
 153   p += 16;
 154
 155   if(conf_req_flag) {
 156       gss_krb5_getsomekey(context_handle, &key);
 157       for (i = 0; i < sizeof(key); ++i)
 158           key[i] ^= 0xf0;
 159       des_set_key (&key, schedule);
 160       memset (&zero, 0, sizeof(zero));
 161       des_cbc_encrypt ((des_cblock *)p,
 162                        (des_cblock *)p,
 163                        8 + input_message_buffer->length + padlength,
 164                        schedule,
 165                        &zero,
 166                        DES_ENCRYPT);
 167
 168       memset (key, 0, sizeof(key));
 169       memset (schedule, 0, sizeof(schedule));
 170   }
 171   if(conf_state != NULL)
 172       *conf_state = conf_req_flag;
 173   return GSS_S_COMPLETE;
 174 }