1 files changed, 550 insertions, 0 deletions

diff --git a/source4/kdc/kdc-heimdal.c b/source4/kdc/kdc-heimdal.c
new file mode 100644
index 0000000..4f7b80d
--- /dev/null
+++ b/source4/kdc/kdc-heimdal.c
@@ -0,0 +1,550 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   KDC Server startup
+
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2008
+   Copyright (C) Andrew Tridgell	2005
+   Copyright (C) Stefan Metzmacher	2005
+
+   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 "samba/process_model.h"
+#include "lib/tsocket/tsocket.h"
+#include "lib/messaging/irpc.h"
+#include "librpc/gen_ndr/ndr_irpc.h"
+#include "librpc/gen_ndr/ndr_krb5pac.h"
+#include "lib/socket/netif.h"
+#include "param/param.h"
+#include "kdc/kdc-server.h"
+#include "kdc/kdc-proxy.h"
+#include "kdc/kdc-glue.h"
+#include "kdc/pac-glue.h"
+#include "kdc/kpasswd-service.h"
+#include "dsdb/samdb/samdb.h"
+#include "auth/session.h"
+#include "libds/common/roles.h"
+#include <kdc.h>
+#include <hdb.h>
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_KERBEROS
+
+NTSTATUS server_service_kdc_init(TALLOC_CTX *);
+
+extern struct krb5plugin_kdc_ftable kdc_plugin_table;
+
+/**
+   Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
+   calling conventions
+*/
+
+static kdc_code kdc_process(struct kdc_server *kdc,
+			    TALLOC_CTX *mem_ctx,
+			    DATA_BLOB *input,
+			    DATA_BLOB *reply,
+			    struct tsocket_address *peer_addr,
+			    struct tsocket_address *my_addr,
+			    int datagram_reply)
+{
+	int ret;
+	char *pa;
+	struct sockaddr_storage ss;
+	krb5_data k5_reply;
+	krb5_kdc_configuration *kdc_config =
+		(krb5_kdc_configuration *)kdc->private_data;
+
+	krb5_data_zero(&k5_reply);
+
+	krb5_kdc_update_time(NULL);
+
+	ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
+				sizeof(struct sockaddr_storage));
+	if (ret < 0) {
+		return KDC_ERROR;
+	}
+	pa = tsocket_address_string(peer_addr, mem_ctx);
+	if (pa == NULL) {
+		return KDC_ERROR;
+	}
+
+	DBG_DEBUG("Received KDC packet of length %zu from %s\n",
+		  input->length, pa);
+
+	ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
+					    kdc_config,
+					    input->data, input->length,
+					    &k5_reply,
+					    pa,
+					    (struct sockaddr *) &ss,
+					    datagram_reply);
+	if (ret == -1) {
+		*reply = data_blob(NULL, 0);
+		return KDC_ERROR;
+	}
+
+	if (ret == HDB_ERR_NOT_FOUND_HERE) {
+		*reply = data_blob(NULL, 0);
+		return KDC_PROXY_REQUEST;
+	}
+
+	if (k5_reply.length) {
+		*reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
+		krb5_data_free(&k5_reply);
+	} else {
+		*reply = data_blob(NULL, 0);
+	}
+	return KDC_OK;
+}
+
+/*
+  setup our listening sockets on the configured network interfaces
+*/
+static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc,
+				       struct loadparm_context *lp_ctx,
+				       struct interface *ifaces,
+				       const struct model_ops *model_ops)
+{
+	int num_interfaces;
+	TALLOC_CTX *tmp_ctx = talloc_new(kdc);
+	NTSTATUS status;
+	int i;
+	uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
+	uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
+	bool done_wildcard = false;
+
+	num_interfaces = iface_list_count(ifaces);
+
+	/* if we are allowing incoming packets from any address, then
+	   we need to bind to the wildcard address */
+	if (!lpcfg_bind_interfaces_only(lp_ctx)) {
+		size_t num_binds = 0;
+		char **wcard = iface_list_wildcard(kdc);
+		NT_STATUS_HAVE_NO_MEMORY(wcard);
+		for (i=0; wcard[i]; i++) {
+			if (kdc_port) {
+				status = kdc_add_socket(kdc, model_ops,
+							"kdc", wcard[i], kdc_port,
+							kdc_process, false);
+				if (NT_STATUS_IS_OK(status)) {
+					num_binds++;
+				}
+			}
+
+			if (kpasswd_port) {
+				status = kdc_add_socket(kdc, model_ops,
+							"kpasswd", wcard[i], kpasswd_port,
+							kpasswd_process, false);
+				if (NT_STATUS_IS_OK(status)) {
+					num_binds++;
+				}
+			}
+		}
+		talloc_free(wcard);
+		if (num_binds == 0) {
+			return NT_STATUS_INVALID_PARAMETER_MIX;
+		}
+		done_wildcard = true;
+	}
+
+	for (i=0; i<num_interfaces; i++) {
+		const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
+
+		if (kdc_port) {
+			status = kdc_add_socket(kdc, model_ops,
+						"kdc", address, kdc_port,
+						kdc_process, done_wildcard);
+			NT_STATUS_NOT_OK_RETURN(status);
+		}
+
+		if (kpasswd_port) {
+			status = kdc_add_socket(kdc, model_ops,
+						"kpasswd", address, kpasswd_port,
+						kpasswd_process, done_wildcard);
+			NT_STATUS_NOT_OK_RETURN(status);
+		}
+	}
+
+	talloc_free(tmp_ctx);
+
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
+				 struct kdc_check_generic_kerberos *r)
+{
+	struct PAC_Validate pac_validate;
+	DATA_BLOB srv_sig;
+	struct PAC_SIGNATURE_DATA kdc_sig;
+	struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
+	krb5_kdc_configuration *kdc_config =
+		(krb5_kdc_configuration *)kdc->private_data;
+	enum ndr_err_code ndr_err;
+	int ret;
+	hdb_entry ent;
+	krb5_principal principal;
+
+
+	/* There is no reply to this request */
+	r->out.generic_reply = data_blob(NULL, 0);
+
+	ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
+				       (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (pac_validate.MessageType != NETLOGON_GENERIC_KRB5_PAC_VALIDATE) {
+		/* We don't implement any other message types - such as certificate validation - yet */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
+	    || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
+	    || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
+				  pac_validate.ChecksumLength);
+
+	ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
+				  lpcfg_realm(kdc->task->lp_ctx),
+				  "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
+				  NULL);
+
+	if (ret != 0) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	ret = kdc_config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
+						 kdc_config->db[0],
+						 principal,
+						 HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
+						 0,
+						 &ent);
+
+	if (ret != 0) {
+		hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
+		krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
+
+		return NT_STATUS_LOGON_FAILURE;
+	}
+
+	kdc_sig.type = pac_validate.SignatureType;
+	kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
+					    pac_validate.SignatureLength);
+
+	ret = kdc_check_pac(kdc->smb_krb5_context->krb5_context, srv_sig, &kdc_sig, &ent);
+
+	hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
+	krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
+
+	if (ret != 0) {
+		return NT_STATUS_LOGON_FAILURE;
+	}
+
+	return NT_STATUS_OK;
+}
+
+
+/*
+  startup the kdc task
+*/
+static NTSTATUS kdc_task_init(struct task_server *task)
+{
+	struct kdc_server *kdc;
+	NTSTATUS status;
+	struct interface *ifaces;
+
+	switch (lpcfg_server_role(task->lp_ctx)) {
+	case ROLE_STANDALONE:
+		task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
+		return NT_STATUS_INVALID_DOMAIN_ROLE;
+	case ROLE_DOMAIN_MEMBER:
+		task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
+		return NT_STATUS_INVALID_DOMAIN_ROLE;
+	case ROLE_DOMAIN_PDC:
+	case ROLE_DOMAIN_BDC:
+	case ROLE_IPA_DC:
+		task_server_terminate(
+		    task, "Cannot start KDC as a 'classic Samba' DC", false);
+		return NT_STATUS_INVALID_DOMAIN_ROLE;
+	case ROLE_ACTIVE_DIRECTORY_DC:
+		/* Yes, we want a KDC */
+		break;
+	}
+
+	load_interface_list(task, task->lp_ctx, &ifaces);
+
+	if (iface_list_count(ifaces) == 0) {
+		task_server_terminate(task, "kdc: no network interfaces configured", false);
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	task_server_set_title(task, "task[kdc]");
+
+	kdc = talloc_zero(task, struct kdc_server);
+	if (kdc == NULL) {
+		task_server_terminate(task, "kdc: out of memory", true);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	kdc->task = task;
+	task->private_data = kdc;
+
+	/* start listening on the configured network interfaces */
+	status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces,
+					task->model_ops);
+	if (!NT_STATUS_IS_OK(status)) {
+		task_server_terminate(task, "kdc failed to setup interfaces", true);
+		return status;
+	}
+
+
+	return NT_STATUS_OK;
+}
+
+/*
+  initialise the kdc task after a fork
+*/
+static void kdc_post_fork(struct task_server *task, struct process_details *pd)
+{
+	struct kdc_server *kdc;
+	krb5_kdc_configuration *kdc_config = NULL;
+	NTSTATUS status;
+	krb5_error_code ret;
+	int ldb_ret;
+
+	if (task == NULL) {
+		task_server_terminate(task, "kdc: Null task", true);
+		return;
+	}
+	if (task->private_data == NULL) {
+		task_server_terminate(task, "kdc: No kdc_server info", true);
+		return;
+	}
+	kdc = talloc_get_type_abort(task->private_data, struct kdc_server);
+
+	/* get a samdb connection */
+	kdc->samdb = samdb_connect(kdc,
+				   kdc->task->event_ctx,
+				   kdc->task->lp_ctx,
+				   system_session(kdc->task->lp_ctx),
+				   NULL,
+				   0);
+	if (!kdc->samdb) {
+		DBG_WARNING("kdc_task_init: unable to connect to samdb\n");
+		task_server_terminate(task, "kdc: krb5_init_context samdb connect failed", true);
+		return;
+	}
+
+	ldb_ret = samdb_rodc(kdc->samdb, &kdc->am_rodc);
+	if (ldb_ret != LDB_SUCCESS) {
+		DBG_WARNING("kdc_task_init: "
+			    "Cannot determine if we are an RODC: %s\n",
+			    ldb_errstring(kdc->samdb));
+		task_server_terminate(task, "kdc: krb5_init_context samdb RODC connect failed", true);
+		return;
+	}
+
+	kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);
+
+	initialize_krb5_error_table();
+
+	ret = smb_krb5_init_context(kdc, task->lp_ctx, &kdc->smb_krb5_context);
+	if (ret) {
+		DBG_WARNING("kdc_task_init: krb5_init_context failed (%s)\n",
+			    error_message(ret));
+		task_server_terminate(task, "kdc: krb5_init_context failed", true);
+		return;
+	}
+
+	krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
+
+	ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
+				  &kdc_config);
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to get KDC configuration", true);
+		return;
+	}
+
+	kdc_config->logf = (krb5_log_facility *)kdc->smb_krb5_context->pvt_log_data;
+	kdc_config->db = talloc(kdc, struct HDB *);
+	if (!kdc_config->db) {
+		task_server_terminate(task, "kdc: out of memory", true);
+		return;
+	}
+	kdc_config->num_db = 1;
+
+	/*
+	 * Note with the CVE-2022-37966 patches,
+	 * see https://bugzilla.samba.org/show_bug.cgi?id=15219
+	 * and https://bugzilla.samba.org/show_bug.cgi?id=15237
+	 * we want to use the strongest keys for everything.
+	 *
+	 * Some of these don't have any real effect anymore,
+	 * but it is better to have them as true...
+	 */
+	kdc_config->tgt_use_strongest_session_key = true;
+	kdc_config->preauth_use_strongest_session_key = true;
+	kdc_config->svc_use_strongest_session_key = true;
+	kdc_config->use_strongest_server_key = true;
+
+	kdc_config->force_include_pa_etype_salt = true;
+
+	/*
+	 * For Samba CVE-2020-25719 Require PAC to be present
+	 * This instructs Heimdal to match AD behaviour,
+	 * as seen after Microsoft's CVE-2021-42287 when
+	 * PacRequestorEnforcement is set to 2.
+	 *
+	 * Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=14686
+	 * REF: https://support.microsoft.com/en-au/topic/kb5008380-authentication-updates-cve-2021-42287-9dafac11-e0d0-4cb8-959a-143bd0201041
+	 */
+
+	kdc_config->require_pac = true;
+
+	/*
+	 * By default we enable RFC6113/FAST support,
+	 * but we have an option to disable in order to
+	 * test against a KDC with FAST support.
+	 */
+	kdc_config->enable_fast = lpcfg_kdc_enable_fast(task->lp_ctx);
+
+	{
+		static const char *dummy_string = "Microsoft";
+
+		/*
+		 * The FAST cookie is not cryptographically required,
+		 * provided that the non-AD gss-preauth authentication
+		 * method is removed (as this is the only multi-step
+		 * authentication method).
+		 *
+		 * gss-preauth has been disabled both by not being
+		 * configured and by being made dependent
+		 * configuration for a "real" fast cookie.
+		 *
+		 * The hide_client_names feature in Heimdal is the
+		 * only other state that is persisted in the cookie,
+		 * and this does not need to be in the cookie for
+		 * single-shot authentication protocols such as ENC-TS
+		 * and ENC-CHAL, the standard password protocols in
+		 * AD.
+		 *
+		 * Furthermore, the Heimdal KDC does not fail if the
+		 * client does not supply a FAST cookie, showing that
+		 * the presence of the cookie is not required.
+		 */
+		kdc_config->enable_fast_cookie = false;
+		kdc_config->dummy_fast_cookie = smb_krb5_make_data(discard_const_p(char, dummy_string),
+								   strlen(dummy_string));
+	}
+
+	/*
+	 * Match Windows and RFC6113 and Windows but break older
+	 * Heimdal clients.
+	 */
+	kdc_config->enable_armored_pa_enc_timestamp = false;
+
+	/* Register hdb-samba4 hooks for use as a keytab */
+
+	kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
+	if (!kdc->base_ctx) {
+		task_server_terminate(task, "kdc: out of memory", true);
+		return;
+	}
+
+	kdc->base_ctx->ev_ctx = task->event_ctx;
+	kdc->base_ctx->lp_ctx = task->lp_ctx;
+	kdc->base_ctx->msg_ctx = task->msg_ctx;
+
+	status = hdb_samba4_create_kdc(kdc->base_ctx,
+				       kdc->smb_krb5_context->krb5_context,
+				       &kdc_config->db[0]);
+	if (!NT_STATUS_IS_OK(status)) {
+		task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
+		return;
+	}
+
+	ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
+				   PLUGIN_TYPE_DATA, "hdb_samba4_interface",
+				   &hdb_samba4_interface);
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to register hdb plugin", true);
+		return;
+	}
+
+	kdc->kpasswd_keytab_name = talloc_asprintf(kdc, "HDBGET:samba4:&%p", kdc->base_ctx);
+	if (kdc->kpasswd_keytab_name == NULL) {
+		task_server_terminate(task,
+				      "kdc: Failed to set keytab name",
+				      true);
+		return;
+	}
+
+	ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_get_kt_ops);
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to register keytab plugin", true);
+		return;
+	}
+
+	/* Register KDC hooks */
+	ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
+				   PLUGIN_TYPE_DATA, "kdc",
+				   &kdc_plugin_table);
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to register kdc plugin", true);
+		return;
+	}
+
+	ret = krb5_kdc_plugin_init(kdc->smb_krb5_context->krb5_context);
+
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to init kdc plugin", true);
+		return;
+	}
+
+	ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc_config);
+
+	if(ret) {
+		task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
+		return;
+	}
+	kdc->private_data = kdc_config;
+
+	status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
+			       kdc_check_generic_kerberos, kdc);
+	if (!NT_STATUS_IS_OK(status)) {
+		task_server_terminate(task, "kdc failed to setup monitoring", true);
+		return;
+	}
+
+	irpc_add_name(task->msg_ctx, "kdc_server");
+}
+
+
+/* called at smbd startup - register ourselves as a server service */
+NTSTATUS server_service_kdc_init(TALLOC_CTX *ctx)
+{
+	static const struct service_details details = {
+		.inhibit_fork_on_accept = true,
+		.inhibit_pre_fork = false,
+		.task_init = kdc_task_init,
+		.post_fork = kdc_post_fork
+	};
+	return register_server_service(ctx, "kdc", &details);
+}