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/*
* Copyright (c) 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "gssapi_locl.h"
RCSID("$Id: verify_mic.c,v 1.8 1999/12/02 17:05:04 joda Exp $");
OM_uint32 gss_verify_mic
(OM_uint32 * minor_status,
const gss_ctx_id_t context_handle,
const gss_buffer_t message_buffer,
const gss_buffer_t token_buffer,
gss_qop_t * qop_state
)
{
u_char *p;
struct md5 md5;
u_char hash[16], seq_data[8];
des_key_schedule schedule;
des_cblock key;
des_cblock zero;
int32_t seq_number;
OM_uint32 ret;
p = token_buffer->value;
ret = gssapi_krb5_verify_header (&p,
token_buffer->length,
"\x01\x01");
if (ret)
return ret;
if (memcmp(p, "\x00\x00", 2) != 0)
return GSS_S_BAD_SIG;
p += 2;
if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
return GSS_S_BAD_MIC;
p += 4;
p += 16;
/* verify checksum */
md5_init (&md5);
md5_update (&md5, p - 24, 8);
md5_update (&md5, message_buffer->value,
message_buffer->length);
md5_finito (&md5, hash);
memset (&zero, 0, sizeof(zero));
#if 0
memcpy (&key, context_handle->auth_context->key.keyvalue.data,
sizeof(key));
#endif
memcpy (&key, context_handle->auth_context->remote_subkey->keyvalue.data,
sizeof(key));
des_set_key (&key, schedule);
des_cbc_cksum ((des_cblock *)hash,
(des_cblock *)hash, sizeof(hash), schedule, &zero);
if (memcmp (p - 8, hash, 8) != 0) {
memset (key, 0, sizeof(key));
memset (schedule, 0, sizeof(schedule));
return GSS_S_BAD_MIC;
}
/* verify sequence number */
krb5_auth_getremoteseqnumber (gssapi_krb5_context,
context_handle->auth_context,
&seq_number);
seq_data[0] = (seq_number >> 0) & 0xFF;
seq_data[1] = (seq_number >> 8) & 0xFF;
seq_data[2] = (seq_number >> 16) & 0xFF;
seq_data[3] = (seq_number >> 24) & 0xFF;
memset (seq_data + 4,
(context_handle->more_flags & LOCAL) ? 0xFF : 0,
4);
p -= 16;
des_set_key (&key, schedule);
des_cbc_encrypt ((des_cblock *)p, (des_cblock *)p, 8,
schedule, (des_cblock *)hash, DES_DECRYPT);
memset (key, 0, sizeof(key));
memset (schedule, 0, sizeof(schedule));
if (memcmp (p, seq_data, 8) != 0) {
return GSS_S_BAD_MIC;
}
krb5_auth_setremoteseqnumber (gssapi_krb5_context,
context_handle->auth_context,
++seq_number);
return GSS_S_COMPLETE;
}
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