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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/krb/get_etype_salt_s2kp.c - Retrieve enctype, salt and s2kparams */
/*
* Copyright (C) 2017 by Cloudera, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDER 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 "k5-int.h"
#include "fast.h"
#include "init_creds_ctx.h"
/* Extract etype info from the error message pkt into icc, if it is a
* PREAUTH_REQUIRED error. Otherwise return the protocol error code. */
static krb5_error_code
get_from_error(krb5_context context, krb5_data *pkt,
krb5_init_creds_context icc)
{
krb5_error *error = NULL;
krb5_pa_data **padata = NULL;
krb5_error_code ret;
ret = decode_krb5_error(pkt, &error);
if (ret)
return ret;
ret = krb5int_fast_process_error(context, icc->fast_state, &error, &padata,
NULL);
if (ret)
goto cleanup;
if (error->error != KDC_ERR_PREAUTH_REQUIRED) {
ret = ERROR_TABLE_BASE_krb5 + error->error;
goto cleanup;
}
ret = k5_get_etype_info(context, icc, padata);
cleanup:
krb5_free_pa_data(context, padata);
krb5_free_error(context, error);
return ret;
}
/* Extract etype info from the AS reply pkt into icc. */
static krb5_error_code
get_from_reply(krb5_context context, krb5_data *pkt,
krb5_init_creds_context icc)
{
krb5_kdc_rep *asrep = NULL;
krb5_error_code ret;
krb5_keyblock *strengthen_key = NULL;
ret = decode_krb5_as_rep(pkt, &asrep);
if (ret)
return ret;
ret = krb5int_fast_process_response(context, icc->fast_state, asrep,
&strengthen_key);
if (ret)
goto cleanup;
ret = k5_get_etype_info(context, icc, asrep->padata);
cleanup:
krb5_free_kdc_rep(context, asrep);
krb5_free_keyblock(context, strengthen_key);
return ret;
}
krb5_error_code KRB5_CALLCONV
krb5_get_etype_info(krb5_context context, krb5_principal principal,
krb5_get_init_creds_opt *opt, krb5_enctype *enctype_out,
krb5_data *salt_out, krb5_data *s2kparams_out)
{
krb5_init_creds_context icc = NULL;
krb5_data reply = empty_data(), req = empty_data(), realm = empty_data();
krb5_data salt = empty_data(), s2kparams = empty_data();
unsigned int flags;
int master, tcp_only;
krb5_error_code ret;
*enctype_out = ENCTYPE_NULL;
*salt_out = empty_data();
*s2kparams_out = empty_data();
/* Create an initial creds context and get the initial request packet. */
ret = krb5_init_creds_init(context, principal, NULL, NULL, 0, opt, &icc);
if (ret)
goto cleanup;
ret = krb5_init_creds_step(context, icc, &reply, &req, &realm, &flags);
if (ret)
goto cleanup;
if (flags != KRB5_INIT_CREDS_STEP_FLAG_CONTINUE) {
ret = KRB5KRB_AP_ERR_MSG_TYPE;
goto cleanup;
}
/* Send the packet (possibly once with UDP and again with TCP). */
tcp_only = 0;
for (;;) {
master = 0;
ret = krb5_sendto_kdc(context, &req, &realm, &reply, &master,
tcp_only);
if (ret)
goto cleanup;
icc->etype = ENCTYPE_NULL;
if (krb5_is_krb_error(&reply)) {
ret = get_from_error(context, &reply, icc);
if (ret) {
if (!tcp_only && ret == KRB5KRB_ERR_RESPONSE_TOO_BIG) {
tcp_only = 1;
krb5_free_data_contents(context, &reply);
continue;
}
goto cleanup;
}
} else if (krb5_is_as_rep(&reply)) {
ret = get_from_reply(context, &reply, icc);
if (ret)
goto cleanup;
} else {
ret = KRB5KRB_AP_ERR_MSG_TYPE;
goto cleanup;
}
break;
}
/* If we found no etype-info, return successfully with all null values. */
if (icc->etype == ENCTYPE_NULL)
goto cleanup;
if (icc->default_salt)
ret = krb5_principal2salt(context, principal, &salt);
else if (icc->salt.length > 0)
ret = krb5int_copy_data_contents(context, &icc->salt, &salt);
if (ret)
goto cleanup;
if (icc->s2kparams.length > 0) {
ret = krb5int_copy_data_contents(context, &icc->s2kparams, &s2kparams);
if (ret)
goto cleanup;
}
*salt_out = salt;
*s2kparams_out = s2kparams;
*enctype_out = icc->etype;
salt = empty_data();
s2kparams = empty_data();
cleanup:
krb5_free_data_contents(context, &req);
krb5_free_data_contents(context, &reply);
krb5_free_data_contents(context, &realm);
krb5_free_data_contents(context, &salt);
krb5_free_data_contents(context, &s2kparams);
krb5_init_creds_free(context, icc);
return ret;
}
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