lib/gssapi/krb5/decapsulate.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
  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 (total_len < 1)
  48         return GSS_S_DEFECTIVE_TOKEN;
  49     if (*p++ != 0x60)
  50         return GSS_S_DEFECTIVE_TOKEN;
  51     e = der_get_length (p, total_len - 1, &len, &len_len);
  52     if (e || 1 + len_len + len != total_len)
  53         return GSS_S_DEFECTIVE_TOKEN;
  54     p += len_len;
  55     if (*p++ != 0x06)
  56         return GSS_S_DEFECTIVE_TOKEN;
  57     e = der_get_length (p, total_len - 1 - len_len - 1,
  58                         &mech_len, &foo);
  59     if (e)
  60         return GSS_S_DEFECTIVE_TOKEN;
  61     p += foo;
  62     if (mech_len != GSS_KRB5_MECHANISM->length)
  63         return GSS_S_BAD_MECH;
  64     if (memcmp(p,
  65                GSS_KRB5_MECHANISM->elements,
  66                GSS_KRB5_MECHANISM->length) != 0)
  67         return GSS_S_BAD_MECH;
  68     p += mech_len;
  69     if (memcmp (p, type, 2) != 0)
  70         return GSS_S_DEFECTIVE_TOKEN;
  71     p += 2;
  72     *str = p;
  73     return GSS_S_COMPLETE;
  74 }
  75
  76 /*
  77  * Remove the GSS-API wrapping from `in_token' giving `out_data.
  78  * Does not copy data, so just free `in_token'.
  79  */
  80
  81 OM_uint32
  82 gssapi_krb5_decapsulate(
  83                         gss_buffer_t input_token_buffer,
  84                         krb5_data *out_data,
  85                         char *type
  86 )
  87 {
  88     u_char *p;
  89     OM_uint32 ret;
  90
  91     p = input_token_buffer->value;
  92     ret = gssapi_krb5_verify_header(&p,
  93                                     input_token_buffer->length,
  94                                     type);
  95     if (ret)
  96         return ret;
  97
  98     out_data->length = input_token_buffer->length -
  99         (p - (u_char *)input_token_buffer->value);
 100     out_data->data   = p;
 101     return GSS_S_COMPLETE;
 102 }