lib/gssapi/krb5/decapsulate.c

   1 /*
   2  * Copyright (c) 1997 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
  44 gssapi_krb5_verify_header(u_char **str,
  45                           size_t total_len,
  46                           u_char *type)
  47 {
  48     size_t len, len_len, mech_len, foo;
  49     int e;
  50     u_char *p = *str;
  51
  52     if (*p++ != 0x60)
  53         return GSS_S_DEFECTIVE_TOKEN;
  54     e = der_get_length (p, total_len - 1, &len, &len_len);
  55     if (e || 1 + len_len + len != total_len)
  56         abort ();
  57     p += len_len;
  58     if (*p++ != 0x06)
  59         return GSS_S_DEFECTIVE_TOKEN;
  60     e = der_get_length (p, total_len - 1 - len_len - 1,
  61                         &mech_len, &foo);
  62     if (e)
  63         abort ();
  64     p += foo;
  65     if (mech_len != GSS_KRB5_MECHANISM->length)
  66         return GSS_S_BAD_MECH;
  67     if (memcmp(p,
  68                GSS_KRB5_MECHANISM->elements,
  69                GSS_KRB5_MECHANISM->length) != 0)
  70         return GSS_S_BAD_MECH;
  71     p += mech_len;
  72     if (memcmp (p, type, 2) != 0)
  73         return GSS_S_DEFECTIVE_TOKEN;
  74     p += 2;
  75     *str = p;
  76     return GSS_S_COMPLETE;
  77 }
  78
  79 /*
  80  * Remove the GSS-API wrapping from `in_token' giving `out_data.
  81  * Does not copy data, so just free `in_token'.
  82  */
  83
  84 OM_uint32
  85 gssapi_krb5_decapsulate(
  86                         gss_buffer_t input_token_buffer,
  87                         krb5_data *out_data,
  88                         u_char *type
  89 )
  90 {
  91     u_char *p;
  92     OM_uint32 ret;
  93
  94     p = input_token_buffer->value;
  95     ret = gssapi_krb5_verify_header(&p,
  96                                     input_token_buffer->length,
  97                                     type);
  98     if (ret)
  99         return ret;
 100
 101     out_data->length = input_token_buffer->length -
 102         (p - (u_char *)input_token_buffer->value);
 103     out_data->data   = p;
 104     return GSS_S_COMPLETE;
 105 }