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heimdal/kdc/fast.c
Nicolas Williams c9609cdb37 Initial patch for dealing with AD x-realm key rollover 
AD issues x-realm TGTs with kvno 0.  On key x-realm trust key change
    we need to be able to try current and previous keys for trust, else
    we will have some failures.
2011-11-15 21:53:33 -06:00

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/*
* Copyright (c) 1997-2011 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Portions Copyright (c) 2010 - 2011 Apple 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:
*
* 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 "kdc_locl.h"
static krb5_error_code
get_fastuser_crypto(kdc_request_t r, krb5_enctype enctype, krb5_crypto *crypto)
{
krb5_principal fast_princ;
hdb_entry_ex *fast_user = NULL;
Key *cookie_key = NULL;
krb5_error_code ret;
*crypto = NULL;
ret = krb5_make_principal(r->context, &fast_princ,
KRB5_WELLKNOWN_ORG_H5L_REALM,
KRB5_WELLKNOWN_NAME, "org.h5l.fast-cookie", NULL);
if (ret)
goto out;
ret = _kdc_db_fetch(r->context, r->config, fast_princ,
HDB_F_GET_CLIENT, NULL, NULL, &fast_user);
krb5_free_principal(r->context, fast_princ);
if (ret)
goto out;
if (enctype == KRB5_ENCTYPE_NULL)
ret = _kdc_get_preferred_key(r->context, r->config, fast_user,
"fast-cookie", &enctype, &cookie_key);
else
ret = hdb_enctype2key(r->context, &fast_user->entry, NULL,
enctype, &cookie_key);
if (ret)
goto out;
ret = krb5_crypto_init(r->context, &cookie_key->key, 0, crypto);
if (ret)
goto out;
out:
if (fast_user)
_kdc_free_ent(r->context, fast_user);
return ret;
}
static krb5_error_code
fast_parse_cookie(kdc_request_t r, const PA_DATA *pa)
{
krb5_crypto crypto = NULL;
krb5_error_code ret;
KDCFastCookie data;
krb5_data d1;
size_t len;
ret = decode_KDCFastCookie(pa->padata_value.data,
pa->padata_value.length,
&data, &len);
if (ret)
return ret;
if (len != pa->padata_value.length || strcmp("H5L1", data.version) != 0) {
free_KDCFastCookie(&data);
return KRB5KDC_ERR_POLICY;
}
ret = get_fastuser_crypto(r, data.cookie.etype, &crypto);
if (ret)
goto out;
ret = krb5_decrypt_EncryptedData(r->context, crypto,
KRB5_KU_H5L_COOKIE,
&data.cookie, &d1);
krb5_crypto_destroy(r->context, crypto);
if (ret)
goto out;
ret = decode_KDCFastState(d1.data, d1.length, &r->fast, &len);
krb5_data_free(&d1);
if (ret)
goto out;
if (r->fast.expiration < kdc_time) {
kdc_log(r->context, r->config, 0, "fast cookie expired");
ret = KRB5KDC_ERR_POLICY;
goto out;
}
out:
free_KDCFastCookie(&data);
return ret;
}
static krb5_error_code
fast_add_cookie(kdc_request_t r, METHOD_DATA *method_data)
{
krb5_crypto crypto = NULL;
KDCFastCookie shell;
krb5_error_code ret;
krb5_data data;
size_t size;
memset(&shell, 0, sizeof(shell));
r->fast.expiration = kdc_time + FAST_EXPIRATION_TIME;
ASN1_MALLOC_ENCODE(KDCFastState, data.data, data.length,
&r->fast, &size, ret);
if (ret)
return ret;
heim_assert(size == data.length, "internal asn1 encoder error");
ret = get_fastuser_crypto(r, KRB5_ENCTYPE_NULL, &crypto);
if (ret)
goto out;
ret = krb5_encrypt_EncryptedData(r->context, crypto,
KRB5_KU_H5L_COOKIE,
data.data, data.length, 0,
&shell.cookie);
krb5_crypto_destroy(r->context, crypto);
if (ret)
goto out;
free(data.data);
shell.version = "H5L1";
ASN1_MALLOC_ENCODE(KDCFastCookie, data.data, data.length,
&shell, &size, ret);
free_EncryptedData(&shell.cookie);
if (ret)
goto out;
heim_assert(size == data.length, "internal asn1 encoder error");
ret = krb5_padata_add(r->context, method_data,
KRB5_PADATA_FX_COOKIE,
data.data, data.length);
out:
if (ret)
free(data.data);
return ret;
}
krb5_error_code
_kdc_fast_mk_response(krb5_context context,
krb5_crypto armor_crypto,
METHOD_DATA *pa_data,
krb5_keyblock *strengthen_key,
KrbFastFinished *finished,
krb5uint32 nonce,
krb5_data *data)
{
PA_FX_FAST_REPLY fxfastrep;
KrbFastResponse fastrep;
krb5_error_code ret;
krb5_data buf;
size_t size;
memset(&fxfastrep, 0, sizeof(fxfastrep));
memset(&fastrep, 0, sizeof(fastrep));
krb5_data_zero(data);
if (pa_data) {
fastrep.padata.val = pa_data->val;
fastrep.padata.len = pa_data->len;
}
fastrep.strengthen_key = strengthen_key;
fastrep.finished = finished;
fastrep.nonce = nonce;
ASN1_MALLOC_ENCODE(KrbFastResponse, buf.data, buf.length,
&fastrep, &size, ret);
if (ret)
return ret;
if (buf.length != size)
krb5_abortx(context, "internal asn.1 error");
fxfastrep.element = choice_PA_FX_FAST_REPLY_armored_data;
ret = krb5_encrypt_EncryptedData(context,
armor_crypto,
KRB5_KU_FAST_REP,
buf.data,
buf.length,
0,
&fxfastrep.u.armored_data.enc_fast_rep);
krb5_data_free(&buf);
if (ret)
return ret;
ASN1_MALLOC_ENCODE(PA_FX_FAST_REPLY, data->data, data->length,
&fxfastrep, &size, ret);
free_PA_FX_FAST_REPLY(&fxfastrep);
if (ret)
return ret;
if (data->length != size)
krb5_abortx(context, "internal asn.1 error");
return 0;
}
krb5_error_code
_kdc_fast_mk_error(krb5_context context,
kdc_request_t r,
METHOD_DATA *error_method,
krb5_crypto armor_crypto,
const KDC_REQ_BODY *req_body,
krb5_error_code outer_error,
const char *e_text,
krb5_principal error_client,
krb5_principal error_server,
time_t *csec, int *cusec,
krb5_data *error_msg)
{
krb5_error_code ret;
krb5_data e_data;
size_t size;
krb5_data_zero(&e_data);
if (armor_crypto) {
PA_FX_FAST_REPLY fxfastrep;
KrbFastResponse fastrep;
memset(&fxfastrep, 0, sizeof(fxfastrep));
memset(&fastrep, 0, sizeof(fastrep));
/* first add the KRB-ERROR to the fast errors */
ret = krb5_mk_error(context,
outer_error,
e_text,
NULL,
error_client,
error_server,
NULL,
NULL,
&e_data);
if (ret)
return ret;
ret = krb5_padata_add(context, error_method,
KRB5_PADATA_FX_ERROR,
e_data.data, e_data.length);
if (ret) {
krb5_data_free(&e_data);
return ret;
}
if (/* hide_principal */ 0) {
error_client = NULL;
error_server = NULL;
e_text = NULL;
}
if (r)
ret = fast_add_cookie(r, error_method);
else
ret = krb5_padata_add(context, error_method,
KRB5_PADATA_FX_COOKIE,
NULL, 0);
if (ret) {
kdc_log(r->context, r->config, 0, "failed to add fast cookie with: %d", ret);
free_METHOD_DATA(error_method);
return ret;
}
ret = _kdc_fast_mk_response(context, armor_crypto,
error_method, NULL, NULL,
req_body->nonce, &e_data);
free_METHOD_DATA(error_method);
if (ret)
return ret;
ret = krb5_padata_add(context, error_method,
KRB5_PADATA_FX_FAST,
e_data.data, e_data.length);
if (ret)
return ret;
}
if (error_method && error_method->len) {
ASN1_MALLOC_ENCODE(METHOD_DATA, e_data.data, e_data.length,
error_method, &size, ret);
if (ret)
return ret;
if (e_data.length != size)
krb5_abortx(context, "internal asn.1 error");
}
ret = krb5_mk_error(context,
outer_error,
e_text,
(e_data.length ? &e_data : NULL),
error_client,
error_server,
csec,
cusec,
error_msg);
krb5_data_free(&e_data);
return ret;
}
krb5_error_code
_kdc_fast_unwrap_request(kdc_request_t r)
{
krb5_principal armor_server = NULL;
hdb_entry_ex *armor_user = NULL;
PA_FX_FAST_REQUEST fxreq;
krb5_auth_context ac = NULL;
krb5_ticket *ticket = NULL;
krb5_flags ap_req_options;
Key *armor_key = NULL;
krb5_keyblock armorkey;
krb5_error_code ret;
krb5_ap_req ap_req;
unsigned char *buf;
KrbFastReq fastreq;
size_t len, size;
krb5_data data;
const PA_DATA *pa;
int i = 0;
/*
* First look for FX_COOKIE and and process it
*/
pa = _kdc_find_padata(&r->req, &i, KRB5_PADATA_FX_COOKIE);
if (pa) {
ret = fast_parse_cookie(r, pa);
if (ret)
goto out;
}
i = 0;
pa = _kdc_find_padata(&r->req, &i, KRB5_PADATA_FX_FAST);
if (pa == NULL)
return 0;
ret = decode_PA_FX_FAST_REQUEST(pa->padata_value.data,
pa->padata_value.length,
&fxreq,
&len);
if (ret)
goto out;
if (len != pa->padata_value.length) {
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
if (fxreq.element != choice_PA_FX_FAST_REQUEST_armored_data) {
kdc_log(r->context, r->config, 0,
"AS-REQ FAST contain unknown type: %d", (int)fxreq.element);
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
/* pull out armor key */
if (fxreq.u.armored_data.armor == NULL) {
kdc_log(r->context, r->config, 0,
"AS-REQ armor missing");
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
if (fxreq.u.armored_data.armor->armor_type != 1) {
kdc_log(r->context, r->config, 0,
"AS-REQ armor type not ap-req");
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
ret = krb5_decode_ap_req(r->context,
&fxreq.u.armored_data.armor->armor_value,
&ap_req);
if(ret) {
kdc_log(r->context, r->config, 0, "AP-REQ decode failed");
goto out;
}
/* Save that principal that was in the request */
ret = _krb5_principalname2krb5_principal(r->context,
&armor_server,
ap_req.ticket.sname,
ap_req.ticket.realm);
if (ret) {
free_AP_REQ(&ap_req);
goto out;
}
ret = _kdc_db_fetch(r->context, r->config, armor_server,
HDB_F_GET_SERVER, NULL, NULL, &armor_user);
if(ret == HDB_ERR_NOT_FOUND_HERE) {
kdc_log(r->context, r->config, 5,
"armor key does not have secrets at this KDC, "
"need to proxy");
goto out;
} else if (ret) {
free_AP_REQ(&ap_req);
ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
goto out;
}
ret = hdb_enctype2key(r->context, &armor_user->entry, NULL,
ap_req.ticket.enc_part.etype,
&armor_key);
if (ret) {
free_AP_REQ(&ap_req);
goto out;
}
ret = krb5_verify_ap_req2(r->context, &ac,
&ap_req,
armor_server,
&armor_key->key,
0,
&ap_req_options,
&ticket,
KRB5_KU_AP_REQ_AUTH);
free_AP_REQ(&ap_req);
if (ret)
goto out;
if (ac->remote_subkey == NULL) {
krb5_auth_con_free(r->context, ac);
kdc_log(r->context, r->config, 0,
"FAST AP-REQ remote subkey missing");
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
ret = _krb5_fast_armor_key(r->context,
ac->remote_subkey,
&ticket->ticket.key,
&armorkey,
&r->armor_crypto);
krb5_auth_con_free(r->context, ac);
krb5_free_ticket(r->context, ticket);
if (ret)
goto out;
krb5_free_keyblock_contents(r->context, &armorkey);
/* verify req-checksum of the outer body */
ASN1_MALLOC_ENCODE(KDC_REQ_BODY, buf, len, &r->req.req_body, &size, ret);
if (ret)
goto out;
if (size != len) {
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
ret = krb5_verify_checksum(r->context, r->armor_crypto,
KRB5_KU_FAST_REQ_CHKSUM,
buf, len,
&fxreq.u.armored_data.req_checksum);
free(buf);
if (ret) {
kdc_log(r->context, r->config, 0,
"FAST request have a bad checksum");
goto out;
}
ret = krb5_decrypt_EncryptedData(r->context, r->armor_crypto,
KRB5_KU_FAST_ENC,
&fxreq.u.armored_data.enc_fast_req,
&data);
if (ret) {
kdc_log(r->context, r->config, 0,
"Failed to decrypt FAST request");
goto out;
}
ret = decode_KrbFastReq(data.data, data.length, &fastreq, &size);
if (ret) {
krb5_data_free(&data);
goto out;
}
if (data.length != size) {
krb5_data_free(&data);
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
krb5_data_free(&data);
free_KDC_REQ_BODY(&r->req.req_body);
ret = copy_KDC_REQ_BODY(&fastreq.req_body, &r->req.req_body);
if (ret)
goto out;
/* check for unsupported mandatory options */
if (FastOptions2int(fastreq.fast_options) & 0xfffc) {
kdc_log(r->context, r->config, 0,
"FAST unsupported mandatory option set");
ret = KRB5KDC_ERR_PREAUTH_FAILED;
goto out;
}
/* KDC MUST ignore outer pa data preauth-14 - 6.5.5 */
if (r->req.padata)
free_METHOD_DATA(r->req.padata);
else
ALLOC(r->req.padata);
ret = copy_METHOD_DATA(&fastreq.padata, r->req.padata);
if (ret)
goto out;
free_KrbFastReq(&fastreq);
free_PA_FX_FAST_REQUEST(&fxreq);
out:
if (armor_server)
krb5_free_principal(r->context, armor_server);
if(armor_user)
_kdc_free_ent(r->context, armor_user);
return ret;
}
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