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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* kdc/policy.c - Policy decision routines for KDC */
/*
* Copyright (C) 2017 by Red Hat, 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 "kdc_util.h"
#include "extern.h"
#include "policy.h"
#include "adm_proto.h"
#include <krb5/kdcpolicy_plugin.h>
#include <syslog.h>
typedef struct kdcpolicy_handle_st {
struct krb5_kdcpolicy_vtable_st vt;
krb5_kdcpolicy_moddata moddata;
} *kdcpolicy_handle;
static kdcpolicy_handle *handles;
static void
free_indicators(char **ais)
{
size_t i;
if (ais == NULL)
return;
for (i = 0; ais[i] != NULL; i++)
free(ais[i]);
free(ais);
}
/* Convert inds to a null-terminated list of C strings. */
static krb5_error_code
authind_strings(krb5_data *const *inds, char ***strs_out)
{
krb5_error_code ret;
char **list = NULL;
size_t i, count;
*strs_out = NULL;
for (count = 0; inds != NULL && inds[count] != NULL; count++);
list = k5calloc(count + 1, sizeof(*list), &ret);
if (list == NULL)
goto error;
for (i = 0; i < count; i++) {
list[i] = k5memdup0(inds[i]->data, inds[i]->length, &ret);
if (list[i] == NULL)
goto error;
}
*strs_out = list;
return 0;
error:
free_indicators(list);
return ret;
}
/* Constrain times->endtime to life and times->renew_till to rlife, relative to
* now. */
static void
update_ticket_times(krb5_ticket_times *times, krb5_timestamp now,
krb5_deltat life, krb5_deltat rlife)
{
if (life)
times->endtime = ts_min(ts_incr(now, life), times->endtime);
if (rlife)
times->renew_till = ts_min(ts_incr(now, rlife), times->renew_till);
}
/* Check an AS request against kdcpolicy modules, updating times with any
* module endtime constraints. Set an appropriate status string on error. */
krb5_error_code
check_kdcpolicy_as(krb5_context context, const krb5_kdc_req *request,
const krb5_db_entry *client, const krb5_db_entry *server,
krb5_data *const *auth_indicators, krb5_timestamp kdc_time,
krb5_ticket_times *times, const char **status)
{
krb5_deltat life, rlife;
krb5_error_code ret;
kdcpolicy_handle *hp, h;
char **ais = NULL;
*status = NULL;
ret = authind_strings(auth_indicators, &ais);
if (ret)
goto done;
for (hp = handles; *hp != NULL; hp++) {
h = *hp;
if (h->vt.check_as == NULL)
continue;
ret = h->vt.check_as(context, h->moddata, request, client, server,
(const char **)ais, status, &life, &rlife);
if (ret)
goto done;
update_ticket_times(times, kdc_time, life, rlife);
}
done:
free_indicators(ais);
return ret;
}
/*
* Check the TGS request against the local TGS policy. Accepts an
* authentication indicator for the module policy decisions. Returns 0 and a
* NULL status string on success.
*/
krb5_error_code
check_kdcpolicy_tgs(krb5_context context, const krb5_kdc_req *request,
const krb5_db_entry *server, const krb5_ticket *ticket,
krb5_data *const *auth_indicators, krb5_timestamp kdc_time,
krb5_ticket_times *times, const char **status)
{
krb5_deltat life, rlife;
krb5_error_code ret;
kdcpolicy_handle *hp, h;
char **ais = NULL;
*status = NULL;
ret = authind_strings(auth_indicators, &ais);
if (ret)
goto done;
for (hp = handles; *hp != NULL; hp++) {
h = *hp;
if (h->vt.check_tgs == NULL)
continue;
ret = h->vt.check_tgs(context, h->moddata, request, server, ticket,
(const char **)ais, status, &life, &rlife);
if (ret)
goto done;
update_ticket_times(times, kdc_time, life, rlife);
}
done:
free_indicators(ais);
return ret;
}
void
unload_kdcpolicy_plugins(krb5_context context)
{
kdcpolicy_handle *hp, h;
for (hp = handles; *hp != NULL; hp++) {
h = *hp;
if (h->vt.fini != NULL)
h->vt.fini(context, h->moddata);
free(h);
}
free(handles);
handles = NULL;
}
krb5_error_code
load_kdcpolicy_plugins(krb5_context context)
{
krb5_error_code ret;
krb5_plugin_initvt_fn *modules = NULL, *mod;
kdcpolicy_handle h;
size_t count;
ret = k5_plugin_load_all(context, PLUGIN_INTERFACE_KDCPOLICY, &modules);
if (ret)
goto cleanup;
for (count = 0; modules[count] != NULL; count++);
handles = k5calloc(count + 1, sizeof(*handles), &ret);
if (handles == NULL)
goto cleanup;
count = 0;
for (mod = modules; *mod != NULL; mod++) {
h = k5calloc(1, sizeof(*h), &ret);
if (h == NULL)
goto cleanup;
ret = (*mod)(context, 1, 1, (krb5_plugin_vtable)&h->vt);
if (ret) { /* Version mismatch. */
TRACE_KDCPOLICY_VTINIT_FAIL(context, ret);
free(h);
continue;
}
if (h->vt.init != NULL) {
ret = h->vt.init(context, &h->moddata);
if (ret == KRB5_PLUGIN_NO_HANDLE) {
TRACE_KDCPOLICY_INIT_SKIP(context, h->vt.name);
free(h);
continue;
}
if (ret) {
kdc_err(context, ret, _("while loading policy module %s"),
h->vt.name);
free(h);
goto cleanup;
}
}
handles[count++] = h;
}
ret = 0;
cleanup:
if (ret)
unload_kdcpolicy_plugins(context);
k5_plugin_free_modules(context, modules);
return ret;
}
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