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heimdal/lib/gssapi/krb5/wrap.c

253 lines
7.2 KiB
C

/*
* 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"
/*
* Return initiator subkey, or if that doesn't exists, the subkey.
*/
krb5_error_code
_gsskrb5i_get_initiator_subkey(const gsskrb5_ctx ctx,
krb5_context context,
krb5_keyblock **key)
{
krb5_error_code ret;
*key = NULL;
if (ctx->more_flags & LOCAL) {
ret = krb5_auth_con_getlocalsubkey(context,
ctx->auth_context,
key);
} else {
ret = krb5_auth_con_getremotesubkey(context,
ctx->auth_context,
key);
}
if (ret == 0 && *key == NULL)
ret = krb5_auth_con_getkey(context,
ctx->auth_context,
key);
if (ret == 0 && *key == NULL) {
krb5_set_error_message(context, 0, "No initiator subkey available");
return GSS_KRB5_S_KG_NO_SUBKEY;
}
return ret;
}
krb5_error_code
_gsskrb5i_get_acceptor_subkey(const gsskrb5_ctx ctx,
krb5_context context,
krb5_keyblock **key)
{
krb5_error_code ret;
*key = NULL;
if (ctx->more_flags & LOCAL) {
ret = krb5_auth_con_getremotesubkey(context,
ctx->auth_context,
key);
} else {
ret = krb5_auth_con_getlocalsubkey(context,
ctx->auth_context,
key);
}
if (ret == 0 && *key == NULL) {
krb5_set_error_message(context, 0, "No acceptor subkey available");
return GSS_KRB5_S_KG_NO_SUBKEY;
}
return ret;
}
OM_uint32
_gsskrb5i_get_token_key(const gsskrb5_ctx ctx,
krb5_context context,
krb5_keyblock **key)
{
_gsskrb5i_get_acceptor_subkey(ctx, context, key);
if(*key == NULL) {
/*
* Only use the initiator subkey or ticket session key if an
* acceptor subkey was not required.
*/
if ((ctx->more_flags & ACCEPTOR_SUBKEY) == 0)
_gsskrb5i_get_initiator_subkey(ctx, context, key);
}
if (*key == NULL) {
krb5_set_error_message(context, 0, "No token key available");
return GSS_KRB5_S_KG_NO_SUBKEY;
}
return 0;
}
static OM_uint32
sub_wrap_size (
OM_uint32 req_output_size,
OM_uint32 * max_input_size,
int blocksize,
int extrasize
)
{
size_t len, total_len;
len = 8 + req_output_size + blocksize + extrasize;
_gsskrb5_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
total_len -= req_output_size; /* token length */
if (total_len < req_output_size) {
*max_input_size = (req_output_size - total_len);
(*max_input_size) &= (~(OM_uint32)(blocksize - 1));
} else {
*max_input_size = 0;
}
return GSS_S_COMPLETE;
}
OM_uint32 GSSAPI_CALLCONV
_gsskrb5_wrap_size_limit (
OM_uint32 * minor_status,
gss_const_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
OM_uint32 req_output_size,
OM_uint32 * max_input_size
)
{
krb5_context context;
krb5_keyblock *key;
OM_uint32 ret;
const gsskrb5_ctx ctx = rk_UNCONST(context_handle);
GSSAPI_KRB5_INIT (&context);
if (ctx->more_flags & IS_CFX)
return _gssapi_wrap_size_cfx(minor_status, ctx, context,
conf_req_flag, qop_req,
req_output_size, max_input_size);
HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
ret = _gsskrb5i_get_token_key(ctx, context, &key);
HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
switch (key->keytype) {
case KRB5_ENCTYPE_DES_CBC_CRC :
case KRB5_ENCTYPE_DES_CBC_MD4 :
case KRB5_ENCTYPE_DES_CBC_MD5 :
#ifdef HEIM_WEAK_CRYPTO
ret = sub_wrap_size(req_output_size, max_input_size, 8, 22);
#else
ret = GSS_S_FAILURE;
#endif
break;
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5:
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56:
ret = _gssapi_wrap_size_arcfour(minor_status, ctx, context,
conf_req_flag, qop_req,
req_output_size, max_input_size, key);
break;
case KRB5_ENCTYPE_DES3_CBC_MD5 :
case KRB5_ENCTYPE_DES3_CBC_SHA1 :
ret = sub_wrap_size(req_output_size, max_input_size, 8, 34);
break;
default :
abort();
break;
}
krb5_free_keyblock (context, key);
*minor_status = 0;
return ret;
}
OM_uint32 GSSAPI_CALLCONV
_gsskrb5_wrap
(OM_uint32 * minor_status,
gss_const_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
const gss_buffer_t input_message_buffer,
int * conf_state,
gss_buffer_t output_message_buffer
)
{
krb5_context context;
krb5_keyblock *key;
OM_uint32 ret;
const gsskrb5_ctx ctx = rk_UNCONST(context_handle);
output_message_buffer->value = NULL;
output_message_buffer->length = 0;
GSSAPI_KRB5_INIT (&context);
if (ctx->more_flags & IS_CFX)
return _gssapi_wrap_cfx (minor_status, ctx, context, conf_req_flag,
input_message_buffer, conf_state,
output_message_buffer);
HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
ret = _gsskrb5i_get_token_key(ctx, context, &key);
HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
if (ret) {
*minor_status = ret;
return GSS_S_FAILURE;
}
switch (key->keytype) {
case KRB5_ENCTYPE_DES_CBC_CRC :
case KRB5_ENCTYPE_DES_CBC_MD4 :
case KRB5_ENCTYPE_DES_CBC_MD5 :
ret = GSS_S_FAILURE;
break;
case KRB5_ENCTYPE_DES3_CBC_MD5 :
case KRB5_ENCTYPE_DES3_CBC_SHA1 :
ret = GSS_S_FAILURE;
break;
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5:
case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56:
ret = _gssapi_wrap_arcfour (minor_status, ctx, context, conf_req_flag,
qop_req, input_message_buffer, conf_state,
output_message_buffer, key);
break;
default :
abort();
break;
}
krb5_free_keyblock (context, key);
return ret;
}