lib/gssapi/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. 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
  39 gssapi_krb5_verify_header(u_char **str,
  40                           size_t total_len,
  41                           char *type)
  42 {
  43     size_t len, len_len, mech_len, foo;
  44     int e;
  45     u_char *p = *str;
  46
  47     if (*p++ != 0x60)
  48         return GSS_S_DEFECTIVE_TOKEN;
  49     e = der_get_length (p, total_len - 1, &len, &len_len);
  50     if (e || 1 + len_len + len != total_len)
  51         abort ();
  52     p += len_len;
  53     if (*p++ != 0x06)
  54         return GSS_S_DEFECTIVE_TOKEN;
  55     e = der_get_length (p, total_len - 1 - len_len - 1,
  56                         &mech_len, &foo);
  57     if (e)
  58         abort ();
  59     p += foo;
  60     if (mech_len != GSS_KRB5_MECHANISM->length)
  61         return GSS_S_BAD_MECH;
  62     if (memcmp(p,
  63                GSS_KRB5_MECHANISM->elements,
  64                GSS_KRB5_MECHANISM->length) != 0)
  65         return GSS_S_BAD_MECH;
  66     p += mech_len;
  67     if (memcmp (p, type, 2) != 0)
  68         return GSS_S_DEFECTIVE_TOKEN;
  69     p += 2;
  70     *str = p;
  71     return GSS_S_COMPLETE;
  72 }
  73
  74 /*
  75  * Remove the GSS-API wrapping from `in_token' giving `out_data.
  76  * Does not copy data, so just free `in_token'.
  77  */
  78
  79 OM_uint32
  80 gssapi_krb5_decapsulate(
  81                         gss_buffer_t input_token_buffer,
  82                         krb5_data *out_data,
  83                         char *type
  84 )
  85 {
  86     u_char *p;
  87     OM_uint32 ret;
  88
  89     p = input_token_buffer->value;
  90     ret = gssapi_krb5_verify_header(&p,
  91                                     input_token_buffer->length,
  92                                     type);
  93     if (ret)
  94         return ret;
  95
  96     out_data->length = input_token_buffer->length -
  97         (p - (u_char *)input_token_buffer->value);
  98     out_data->data   = p;
  99     return GSS_S_COMPLETE;
 100 }