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/*
* Copyright (c) 1997 - 2003 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 "gsskrb5_locl.h"
krb5_error_code
_gsskrb5_encode_om_uint32(OM_uint32 n, u_char *p)
{
p[0] = (n >> 0) & 0xFF;
p[1] = (n >> 8) & 0xFF;
p[2] = (n >> 16) & 0xFF;
p[3] = (n >> 24) & 0xFF;
return 0;
}
krb5_error_code
_gsskrb5_encode_be_om_uint32(OM_uint32 n, u_char *p)
{
p[0] = (n >> 24) & 0xFF;
p[1] = (n >> 16) & 0xFF;
p[2] = (n >> 8) & 0xFF;
p[3] = (n >> 0) & 0xFF;
return 0;
}
krb5_error_code
_gsskrb5_decode_om_uint32(const void *ptr, OM_uint32 *n)
{
const u_char *p = ptr;
*n = (p[0] << 0) | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
return 0;
}
krb5_error_code
_gsskrb5_decode_be_om_uint32(const void *ptr, OM_uint32 *n)
{
const u_char *p = ptr;
*n = (p[0] <<24) | (p[1] << 16) | (p[2] << 8) | (p[3] << 0);
return 0;
}
static krb5_error_code
hash_input_chan_bindings (const gss_channel_bindings_t b,
u_char *p)
{
u_char num[4];
EVP_MD_CTX *ctx;
ctx = EVP_MD_CTX_create();
EVP_DigestInit_ex(ctx, EVP_md5(), NULL);
_gsskrb5_encode_om_uint32 (b->initiator_addrtype, num);
EVP_DigestUpdate(ctx, num, sizeof(num));
_gsskrb5_encode_om_uint32 (b->initiator_address.length, num);
EVP_DigestUpdate(ctx, num, sizeof(num));
if (b->initiator_address.length)
EVP_DigestUpdate(ctx,
b->initiator_address.value,
b->initiator_address.length);
_gsskrb5_encode_om_uint32 (b->acceptor_addrtype, num);
EVP_DigestUpdate(ctx, num, sizeof(num));
_gsskrb5_encode_om_uint32 (b->acceptor_address.length, num);
EVP_DigestUpdate(ctx, num, sizeof(num));
if (b->acceptor_address.length)
EVP_DigestUpdate(ctx,
b->acceptor_address.value,
b->acceptor_address.length);
_gsskrb5_encode_om_uint32 (b->application_data.length, num);
EVP_DigestUpdate(ctx, num, sizeof(num));
if (b->application_data.length)
EVP_DigestUpdate(ctx,
b->application_data.value,
b->application_data.length);
EVP_DigestFinal_ex(ctx, p, NULL);
EVP_MD_CTX_destroy(ctx);
return 0;
}
/*
* create a checksum over the chanel bindings in
* `input_chan_bindings', `flags' and `fwd_data' and return it in
* `result'
*/
OM_uint32
_gsskrb5_create_8003_checksum (
OM_uint32 *minor_status,
const gss_channel_bindings_t input_chan_bindings,
OM_uint32 flags,
const krb5_data *fwd_data,
Checksum *result)
{
u_char *p;
/*
* see rfc1964 (section 1.1.1 (Initial Token), and the checksum value
* field's format) */
result->cksumtype = CKSUMTYPE_GSSAPI;
if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG))
result->checksum.length = 24 + 4 + fwd_data->length;
else
result->checksum.length = 24;
result->checksum.data = malloc (result->checksum.length);
if (result->checksum.data == NULL) {
*minor_status = ENOMEM;
return GSS_S_FAILURE;
}
p = result->checksum.data;
_gsskrb5_encode_om_uint32 (16, p);
p += 4;
if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS) {
memset (p, 0, 16);
} else {
hash_input_chan_bindings (input_chan_bindings, p);
}
p += 16;
_gsskrb5_encode_om_uint32 (flags, p);
p += 4;
if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG)) {
*p++ = (1 >> 0) & 0xFF; /* DlgOpt */ /* == 1 */
*p++ = (1 >> 8) & 0xFF; /* DlgOpt */ /* == 0 */
*p++ = (fwd_data->length >> 0) & 0xFF; /* Dlgth */
*p++ = (fwd_data->length >> 8) & 0xFF; /* Dlgth */
memcpy(p, (unsigned char *) fwd_data->data, fwd_data->length);
p += fwd_data->length;
}
return GSS_S_COMPLETE;
}
/*
* verify the checksum in `cksum' over `input_chan_bindings'
* returning `flags' and `fwd_data'
*/
OM_uint32
_gsskrb5_verify_8003_checksum(
OM_uint32 *minor_status,
const gss_channel_bindings_t input_chan_bindings,
const Checksum *cksum,
OM_uint32 *flags,
krb5_data *fwd_data)
{
unsigned char hash[16];
unsigned char *p;
OM_uint32 length;
int DlgOpt;
static unsigned char zeros[16];
if (cksum == NULL) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
/* XXX should handle checksums > 24 bytes */
if(cksum->cksumtype != CKSUMTYPE_GSSAPI || cksum->checksum.length < 24) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
p = cksum->checksum.data;
_gsskrb5_decode_om_uint32(p, &length);
if(length != sizeof(hash)) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
p += 4;
if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS
&& memcmp(p, zeros, sizeof(zeros)) != 0) {
if(hash_input_chan_bindings(input_chan_bindings, hash) != 0) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
if(ct_memcmp(hash, p, sizeof(hash)) != 0) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
}
p += sizeof(hash);
_gsskrb5_decode_om_uint32(p, flags);
p += 4;
if (cksum->checksum.length > 24 && (*flags & GSS_C_DELEG_FLAG)) {
if(cksum->checksum.length < 28) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
DlgOpt = (p[0] << 0) | (p[1] << 8);
p += 2;
if (DlgOpt != 1) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
fwd_data->length = (p[0] << 0) | (p[1] << 8);
p += 2;
if(cksum->checksum.length < 28 + fwd_data->length) {
*minor_status = 0;
return GSS_S_BAD_BINDINGS;
}
fwd_data->data = malloc(fwd_data->length);
if (fwd_data->data == NULL) {
*minor_status = ENOMEM;
return GSS_S_FAILURE;
}
memcpy(fwd_data->data, p, fwd_data->length);
}
return GSS_S_COMPLETE;
}
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