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/*
Unix SMB/CIFS implementation.
implement the DsWriteAccountSpn call
Copyright (C) Stefan Metzmacher 2009
Copyright (C) Andrew Tridgell 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "rpc_server/dcerpc_server.h"
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "system/kerberos.h"
#include "auth/kerberos/kerberos.h"
#include "libcli/security/security.h"
#include "libcli/security/session.h"
#include "rpc_server/drsuapi/dcesrv_drsuapi.h"
#include "librpc/gen_ndr/ndr_drsuapi.h"
#include "auth/session.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_DRS_REPL
#undef strcasecmp
/*
check that the SPN update should be allowed as an override
via sam_ctx_system
This is only called if the client is not a domain controller or
administrator
*/
static bool writespn_check_spn(struct drsuapi_bind_state *b_state,
struct dcesrv_call_state *dce_call,
struct ldb_dn *dn,
const char *spn)
{
/*
* we only allow SPN updates if:
*
* 1) they are on the clients own account object
* 2) they are of the form SERVICE/dnshostname
*/
struct auth_session_info *session_info =
dcesrv_call_session_info(dce_call);
struct dom_sid *user_sid, *sid;
TALLOC_CTX *tmp_ctx = talloc_new(dce_call);
struct ldb_result *res;
const char *attrs[] = { "objectSID", "dNSHostName", NULL };
int ret;
krb5_context krb_ctx;
krb5_error_code kerr;
krb5_principal principal;
krb5_data component;
const char *dns_name, *dnsHostName;
/* The service principal name shouldn't be NULL */
if (spn == NULL) {
talloc_free(tmp_ctx);
return false;
}
/*
get the objectSid of the DN that is being modified, and
check it matches the user_sid in their token
*/
ret = dsdb_search_dn(b_state->sam_ctx, tmp_ctx, &res, dn, attrs,
DSDB_SEARCH_ONE_ONLY);
if (ret != LDB_SUCCESS) {
talloc_free(tmp_ctx);
return false;
}
user_sid = &session_info->security_token->sids[PRIMARY_USER_SID_INDEX];
sid = samdb_result_dom_sid(tmp_ctx, res->msgs[0], "objectSid");
if (sid == NULL) {
talloc_free(tmp_ctx);
return false;
}
dnsHostName = ldb_msg_find_attr_as_string(res->msgs[0], "dNSHostName",
NULL);
if (dnsHostName == NULL) {
talloc_free(tmp_ctx);
return false;
}
if (!dom_sid_equal(sid, user_sid)) {
talloc_free(tmp_ctx);
return false;
}
kerr = smb_krb5_init_context_basic(tmp_ctx,
dce_call->conn->dce_ctx->lp_ctx,
&krb_ctx);
if (kerr != 0) {
talloc_free(tmp_ctx);
return false;
}
kerr = krb5_parse_name_flags(krb_ctx, spn, KRB5_PRINCIPAL_PARSE_NO_REALM,
&principal);
if (kerr != 0) {
krb5_free_context(krb_ctx);
talloc_free(tmp_ctx);
return false;
}
if (krb5_princ_size(krb_ctx, principal) != 2) {
krb5_free_principal(krb_ctx, principal);
krb5_free_context(krb_ctx);
talloc_free(tmp_ctx);
return false;
}
kerr = smb_krb5_princ_component(krb_ctx, principal, 1, &component);
if (kerr) {
krb5_free_principal(krb_ctx, principal);
krb5_free_context(krb_ctx);
talloc_free(tmp_ctx);
return false;
}
dns_name = (const char *)component.data;
if (strcasecmp(dns_name, dnsHostName) != 0) {
krb5_free_principal(krb_ctx, principal);
krb5_free_context(krb_ctx);
talloc_free(tmp_ctx);
return false;
}
/* its a simple update on their own account - allow it with
* permissions override */
krb5_free_principal(krb_ctx, principal);
krb5_free_context(krb_ctx);
talloc_free(tmp_ctx);
return true;
}
/*
drsuapi_DsWriteAccountSpn
*/
WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx,
struct drsuapi_DsWriteAccountSpn *r)
{
struct drsuapi_bind_state *b_state;
struct dcesrv_handle *h;
*r->out.level_out = r->in.level;
DCESRV_PULL_HANDLE_WERR(h, r->in.bind_handle, DRSUAPI_BIND_HANDLE);
b_state = h->data;
r->out.res = talloc(mem_ctx, union drsuapi_DsWriteAccountSpnResult);
W_ERROR_HAVE_NO_MEMORY(r->out.res);
switch (r->in.level) {
case 1: {
struct drsuapi_DsWriteAccountSpnRequest1 *req;
struct ldb_message *msg;
uint32_t count;
unsigned int i;
int ret;
unsigned spn_count=0;
bool passed_checks = true;
struct ldb_context *sam_ctx;
req = &r->in.req->req1;
count = req->count;
msg = ldb_msg_new(mem_ctx);
if (msg == NULL) {
return WERR_NOT_ENOUGH_MEMORY;
}
msg->dn = ldb_dn_new(msg, b_state->sam_ctx,
req->object_dn);
if ( ! ldb_dn_validate(msg->dn)) {
r->out.res->res1.status = WERR_OK;
return WERR_OK;
}
/* construct mods */
for (i = 0; i < count; i++) {
if (!writespn_check_spn(b_state,
dce_call,
msg->dn,
req->spn_names[i].str)) {
passed_checks = false;
}
ret = ldb_msg_add_string(msg,
"servicePrincipalName",
req->spn_names[i].str);
if (ret != LDB_SUCCESS) {
return WERR_NOT_ENOUGH_MEMORY;
}
spn_count++;
}
if (msg->num_elements == 0) {
DEBUG(2,("No SPNs need changing on %s\n",
ldb_dn_get_linearized(msg->dn)));
r->out.res->res1.status = WERR_OK;
return WERR_OK;
}
for (i=0;i<msg->num_elements;i++) {
switch (req->operation) {
case DRSUAPI_DS_SPN_OPERATION_ADD:
msg->elements[i].flags = LDB_FLAG_MOD_ADD;
break;
case DRSUAPI_DS_SPN_OPERATION_REPLACE:
msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
break;
case DRSUAPI_DS_SPN_OPERATION_DELETE:
msg->elements[i].flags = LDB_FLAG_MOD_DELETE;
break;
}
}
if (passed_checks && b_state->sam_ctx_system) {
sam_ctx = b_state->sam_ctx_system;
} else {
sam_ctx = b_state->sam_ctx;
}
/* Apply to database */
ret = dsdb_modify(sam_ctx, msg, DSDB_MODIFY_PERMISSIVE);
if (ret != LDB_SUCCESS) {
DEBUG(0,("Failed to modify SPNs on %s: %s\n",
ldb_dn_get_linearized(msg->dn),
ldb_errstring(b_state->sam_ctx)));
NDR_PRINT_IN_DEBUG(
drsuapi_DsWriteAccountSpn, r);
r->out.res->res1.status = WERR_ACCESS_DENIED;
} else {
DEBUG(2,("Modified %u SPNs on %s\n", spn_count,
ldb_dn_get_linearized(msg->dn)));
r->out.res->res1.status = WERR_OK;
}
return WERR_OK;
}
}
return WERR_INVALID_LEVEL;
}
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