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samba-mirror/auth/gensec/gensec_util.c
Stefan Metzmacher e2d271cb6b CVE-2020-25719 CVE-2020-25717: auth/gensec: always require a PAC in domain mode (DC or member)
AD domains always provide a PAC unless UF_NO_AUTH_DATA_REQUIRED is set
on the service account, which can only be explicitly configured,
but that's an invalid configuration!

We still try to support standalone servers in an MIT realm,
as legacy setup.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14801
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14556

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

[jsutton@samba.org Removed knownfail entries]
2021-11-09 19:45:33 +00:00

339 lines
9.1 KiB
C

/*
Unix SMB/CIFS implementation.
Generic Authentication Interface
Copyright (C) Andrew Tridgell 2003
Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2006
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 "auth/gensec/gensec.h"
#include "auth/gensec/gensec_internal.h"
#include "auth/common_auth.h"
#include "../lib/util/asn1.h"
#include "param/param.h"
#include "libds/common/roles.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_AUTH
NTSTATUS gensec_generate_session_info_pac(TALLOC_CTX *mem_ctx,
struct gensec_security *gensec_security,
struct smb_krb5_context *smb_krb5_context,
DATA_BLOB *pac_blob,
const char *principal_string,
const struct tsocket_address *remote_address,
struct auth_session_info **session_info)
{
uint32_t session_info_flags = 0;
struct auth4_context *auth_context = NULL;
NTSTATUS status;
if (gensec_security->want_features & GENSEC_FEATURE_UNIX_TOKEN) {
session_info_flags |= AUTH_SESSION_INFO_UNIX_TOKEN;
}
session_info_flags |= AUTH_SESSION_INFO_DEFAULT_GROUPS;
if (!pac_blob) {
enum server_role server_role =
lpcfg_server_role(gensec_security->settings->lp_ctx);
/*
* For any domain setup (DC or member) we require having
* a PAC, as the service ticket comes from an AD DC,
* which will always provide a PAC, unless
* UF_NO_AUTH_DATA_REQUIRED is configured for our
* account, but that's just an invalid configuration,
* the admin configured for us!
*
* As a legacy case, we still allow kerberos tickets from an MIT
* realm, but only in standalone mode. In that mode we'll only
* ever accept a kerberos authentication with a keytab file
* being explicitly configured via the 'keytab method' option.
*/
if (server_role != ROLE_STANDALONE) {
DBG_WARNING("Unable to find PAC in ticket from %s, "
"failing to allow access\n",
principal_string);
return NT_STATUS_NO_IMPERSONATION_TOKEN;
}
DBG_NOTICE("Unable to find PAC for %s, resorting to local "
"user lookup\n", principal_string);
}
auth_context = gensec_security->auth_context;
if ((auth_context == NULL) ||
(auth_context->generate_session_info_pac == NULL)) {
DBG_ERR("Cannot generate a session_info without "
"the auth_context\n");
return NT_STATUS_INTERNAL_ERROR;
}
status = auth_context->generate_session_info_pac(
auth_context,
mem_ctx,
smb_krb5_context,
pac_blob,
principal_string,
remote_address,
session_info_flags,
session_info);
return status;
}
/*
magic check a GSS-API wrapper packet for an Kerberos OID
*/
static bool gensec_gssapi_check_oid(const DATA_BLOB *blob, const char *oid)
{
bool ret = false;
struct asn1_data *data = asn1_init(NULL, ASN1_MAX_TREE_DEPTH);
if (!data) return false;
if (!asn1_load(data, *blob)) goto err;
if (!asn1_start_tag(data, ASN1_APPLICATION(0))) goto err;
if (!asn1_check_OID(data, oid)) goto err;
ret = !asn1_has_error(data);
err:
asn1_free(data);
return ret;
}
/**
* Check if the packet is one for the KRB5 mechansim
*
* NOTE: This is a helper that can be employed by multiple mechanisms, do
* not make assumptions about the private_data
*
* @param gensec_security GENSEC state, unused
* @param in The request, as a DATA_BLOB
* @return Error, INVALID_PARAMETER if it's not a packet for us
* or NT_STATUS_OK if the packet is ok.
*/
NTSTATUS gensec_magic_check_krb5_oid(struct gensec_security *unused,
const DATA_BLOB *blob)
{
if (gensec_gssapi_check_oid(blob, GENSEC_OID_KERBEROS5)) {
return NT_STATUS_OK;
} else {
return NT_STATUS_INVALID_PARAMETER;
}
}
void gensec_child_want_feature(struct gensec_security *gensec_security,
uint32_t feature)
{
struct gensec_security *child_security = gensec_security->child_security;
gensec_security->want_features |= feature;
if (child_security == NULL) {
return;
}
gensec_want_feature(child_security, feature);
}
bool gensec_child_have_feature(struct gensec_security *gensec_security,
uint32_t feature)
{
struct gensec_security *child_security = gensec_security->child_security;
if (feature & GENSEC_FEATURE_SIGN_PKT_HEADER) {
/*
* All mechs with sub (child) mechs need to provide DCERPC
* header signing! This is required because the negotiation
* of header signing is done before the authentication
* is completed.
*/
return true;
}
if (child_security == NULL) {
return false;
}
return gensec_have_feature(child_security, feature);
}
NTSTATUS gensec_child_unseal_packet(struct gensec_security *gensec_security,
uint8_t *data, size_t length,
const uint8_t *whole_pdu, size_t pdu_length,
const DATA_BLOB *sig)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_unseal_packet(gensec_security->child_security,
data, length,
whole_pdu, pdu_length,
sig);
}
NTSTATUS gensec_child_check_packet(struct gensec_security *gensec_security,
const uint8_t *data, size_t length,
const uint8_t *whole_pdu, size_t pdu_length,
const DATA_BLOB *sig)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_check_packet(gensec_security->child_security,
data, length,
whole_pdu, pdu_length,
sig);
}
NTSTATUS gensec_child_seal_packet(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
uint8_t *data, size_t length,
const uint8_t *whole_pdu, size_t pdu_length,
DATA_BLOB *sig)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_seal_packet(gensec_security->child_security,
mem_ctx,
data, length,
whole_pdu, pdu_length,
sig);
}
NTSTATUS gensec_child_sign_packet(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
const uint8_t *data, size_t length,
const uint8_t *whole_pdu, size_t pdu_length,
DATA_BLOB *sig)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_sign_packet(gensec_security->child_security,
mem_ctx,
data, length,
whole_pdu, pdu_length,
sig);
}
NTSTATUS gensec_child_wrap(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
const DATA_BLOB *in,
DATA_BLOB *out)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_wrap(gensec_security->child_security,
mem_ctx, in, out);
}
NTSTATUS gensec_child_unwrap(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
const DATA_BLOB *in,
DATA_BLOB *out)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_unwrap(gensec_security->child_security,
mem_ctx, in, out);
}
size_t gensec_child_sig_size(struct gensec_security *gensec_security,
size_t data_size)
{
if (gensec_security->child_security == NULL) {
return 0;
}
return gensec_sig_size(gensec_security->child_security, data_size);
}
size_t gensec_child_max_input_size(struct gensec_security *gensec_security)
{
if (gensec_security->child_security == NULL) {
return 0;
}
return gensec_max_input_size(gensec_security->child_security);
}
size_t gensec_child_max_wrapped_size(struct gensec_security *gensec_security)
{
if (gensec_security->child_security == NULL) {
return 0;
}
return gensec_max_wrapped_size(gensec_security->child_security);
}
NTSTATUS gensec_child_session_key(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
DATA_BLOB *session_key)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_session_key(gensec_security->child_security,
mem_ctx,
session_key);
}
NTSTATUS gensec_child_session_info(struct gensec_security *gensec_security,
TALLOC_CTX *mem_ctx,
struct auth_session_info **session_info)
{
if (gensec_security->child_security == NULL) {
return NT_STATUS_INVALID_PARAMETER;
}
return gensec_session_info(gensec_security->child_security,
mem_ctx,
session_info);
}
NTTIME gensec_child_expire_time(struct gensec_security *gensec_security)
{
if (gensec_security->child_security == NULL) {
return GENSEC_EXPIRE_TIME_INFINITY;
}
return gensec_expire_time(gensec_security->child_security);
}
const char *gensec_child_final_auth_type(struct gensec_security *gensec_security)
{
if (gensec_security->child_security == NULL) {
return "NONE";
}
return gensec_final_auth_type(gensec_security->child_security);
}