auth_log.c

/*

   Authentication and authorization logging

   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2017

   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/>.
*/

/*
 * Debug log levels for authentication logging (these both map to
 * LOG_NOTICE in syslog)
 */
#define AUTH_FAILURE_LEVEL 2
#define AUTH_SUCCESS_LEVEL 3
#define AUTHZ_SUCCESS_LEVEL 4

/* 5 is used for both authentication and authorization */
#define AUTH_ANONYMOUS_LEVEL 5
#define AUTHZ_ANONYMOUS_LEVEL 5

#define AUTHZ_JSON_TYPE "Authorization"
#define AUTH_JSON_TYPE  "Authentication"

/*
 * JSON message version numbers
 *
 * If adding a field increment the minor version
 * If removing or changing the format/meaning of a field
 * increment the major version.
 */
#define AUTH_MAJOR 1
#define AUTH_MINOR 2
#define AUTHZ_MAJOR 1
#define AUTHZ_MINOR 1

#include "includes.h"
#include "../lib/tsocket/tsocket.h"
#include "common_auth.h"
#include "lib/util/util_str_escape.h"
#include "libcli/security/dom_sid.h"
#include "libcli/security/security_token.h"
#include "librpc/gen_ndr/server_id.h"
#include "source4/lib/messaging/messaging.h"
#include "source4/lib/messaging/irpc.h"
#include "lib/util/server_id_db.h"
#include "lib/param/param.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/windows_event_ids.h"
#include "lib/audit_logging/audit_logging.h"

/*
 * Determine the type of the password supplied for the
 * authorisation attempt.
 *
 */
static const char* get_password_type(const struct auth_usersupplied_info *ui);

#ifdef HAVE_JANSSON

#include <jansson.h>
#include "system/time.h"

/*
 * Write the json object to the debug logs.
 *
 */
static void log_json(struct imessaging_context *msg_ctx,
		     struct loadparm_context *lp_ctx,
		     struct json_object *object,
		     int debug_class,
		     int debug_level)
{
	audit_log_json(object, debug_class, debug_level);
	if (msg_ctx && lp_ctx && lpcfg_auth_event_notification(lp_ctx)) {
		audit_message_send(msg_ctx,
				   AUTH_EVENT_NAME,
				   MSG_AUTH_LOG,
				   object);
	}
}

/*
 * Determine the Windows logon type for the current authorisation attempt.
 *
 * Currently Samba only supports
 *
 * 2 Interactive      A user logged on to this computer.
 * 3 Network          A user or computer logged on to this computer from
 *                    the network.
 * 8 NetworkCleartext A user logged on to this computer from the network.
 *                    The user's password was passed to the authentication
 *                    package in its unhashed form.
 *
 */
static enum event_logon_type get_logon_type(
	const struct auth_usersupplied_info *ui)
{
	if ((ui->logon_parameters & MSV1_0_CLEARTEXT_PASSWORD_SUPPLIED)
	   || (ui->password_state == AUTH_PASSWORD_PLAIN)) {
		return EVT_LOGON_NETWORK_CLEAR_TEXT;
	} else if (ui->flags & USER_INFO_INTERACTIVE_LOGON) {
		return EVT_LOGON_INTERACTIVE;
	}
	return EVT_LOGON_NETWORK;
}

/*
 * Write a machine parsable json formatted authentication log entry.
 *
 * IF removing or changing the format/meaning of a field please update the
 *    major version number AUTH_MAJOR
 *
 * IF adding a new field please update the minor version number AUTH_MINOR
 *
 *  To process the resulting log lines from the commend line use jq to
 *  parse the json.
 *
 *  grep "^  {" log file |
 *  jq -rc '"\(.timestamp)\t\(.Authentication.status)\t
 *           \(.Authentication.clientDomain)\t
 *           \(.Authentication.clientAccount)
 *           \t\(.Authentication.workstation)
 *           \t\(.Authentication.remoteAddress)
 *           \t\(.Authentication.localAddress)"'
 */
static void log_authentication_event_json(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct timeval *start_time,
	const struct auth_usersupplied_info *ui,
	NTSTATUS status,
	const char *domain_name,
	const char *account_name,
	struct dom_sid *sid,
	enum event_id_type event_id,
	int debug_level)
{
	struct json_object wrapper = json_empty_object;
	struct json_object authentication = json_empty_object;
	char negotiate_flags[11];
	char logon_id[19];
	int rc = 0;

	authentication = json_new_object();
	if (json_is_invalid(&authentication)) {
		goto failure;
	}
	rc = json_add_version(&authentication, AUTH_MAJOR, AUTH_MINOR);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_int(&authentication,
			  "eventId",
			  event_id);
	if (rc != 0) {
		goto failure;
	}
	snprintf(logon_id,
		 sizeof( logon_id),
		 "%"PRIx64"",
		 ui->logon_id);
	rc = json_add_string(&authentication, "logonId", logon_id);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_int(&authentication, "logonType", get_logon_type(ui));
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authentication, "status", nt_errstr(status));
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_address(&authentication, "localAddress", ui->local_host);
	if (rc != 0) {
		goto failure;
	}
	rc =
	    json_add_address(&authentication, "remoteAddress", ui->remote_host);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "serviceDescription", ui->service_description);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "authDescription", ui->auth_description);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "clientDomain", ui->client.domain_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "clientAccount", ui->client.account_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "workstation", ui->workstation_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authentication, "becameAccount", account_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authentication, "becameDomain", domain_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_sid(&authentication, "becameSid", sid);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "mappedAccount", ui->mapped.account_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "mappedDomain", ui->mapped.domain_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authentication,
			     "netlogonComputer",
			     ui->netlogon_trust_account.computer_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authentication,
			     "netlogonTrustAccount",
			     ui->netlogon_trust_account.account_name);
	if (rc != 0) {
		goto failure;
	}
	snprintf(negotiate_flags,
		 sizeof( negotiate_flags),
		 "0x%08X",
		 ui->netlogon_trust_account.negotiate_flags);
	rc = json_add_string(
	    &authentication, "netlogonNegotiateFlags", negotiate_flags);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_int(&authentication,
			  "netlogonSecureChannelType",
			  ui->netlogon_trust_account.secure_channel_type);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_sid(&authentication,
			  "netlogonTrustAccountSid",
			  ui->netlogon_trust_account.sid);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authentication, "passwordType", get_password_type(ui));
	if (rc != 0) {
		goto failure;
	}

	wrapper = json_new_object();
	if (json_is_invalid(&wrapper)) {
		goto failure;
	}
	rc = json_add_timestamp(&wrapper);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&wrapper, "type", AUTH_JSON_TYPE);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_object(&wrapper, AUTH_JSON_TYPE, &authentication);
	if (rc != 0) {
		goto failure;
	}

	/*
	 * While not a general-purpose profiling solution this will
	 * assist some to determine how long NTLM and KDC
	 * authentication takes once this process can handle it.  This
	 * covers transactions elsewhere but not (eg) the delay while
	 * this is waiting unread on the input socket.
	 */
	if (start_time != NULL) {
		struct timeval current_time = timeval_current();
		uint64_t duration =  usec_time_diff(&current_time,
						    start_time);
		rc = json_add_int(&authentication, "duration", duration);
		if (rc != 0) {
			goto failure;
		}
	}

	log_json(msg_ctx,
		 lp_ctx,
		 &wrapper,
		 DBGC_AUTH_AUDIT_JSON,
		 debug_level);
	json_free(&wrapper);
	return;
failure:
	/*
	 * On a failure authentication will not have been added to wrapper so it
	 * needs to be freed to avoid a leak.
	 *
	 */
	json_free(&authentication);
	json_free(&wrapper);
	DBG_ERR("Failed to write authentication event JSON log message\n");
}

/*
 * Log details of a successful authorization to a service,
 * in a machine parsable json format
 *
 * IF removing or changing the format/meaning of a field please update the
 *    major version number AUTHZ_MAJOR
 *
 * IF adding a new field please update the minor version number AUTHZ_MINOR
 *
 *  To process the resulting log lines from the commend line use jq to
 *  parse the json.
 *
 *  grep "^  {" log_file |\
 *  jq -rc '"\(.timestamp)\t
 *           \(.Authorization.domain)\t
 *           \(.Authorization.account)\t
 *           \(.Authorization.remoteAddress)"'
 *
 */
static void log_successful_authz_event_json(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct tsocket_address *remote,
	const struct tsocket_address *local,
	const char *service_description,
	const char *auth_type,
	const char *transport_protection,
	struct auth_session_info *session_info,
	int debug_level)
{
	struct json_object wrapper = json_empty_object;
	struct json_object authorization = json_empty_object;
	char account_flags[11];
	int rc = 0;

	authorization = json_new_object();
	if (json_is_invalid(&authorization)) {
		goto failure;
	}
	rc = json_add_version(&authorization, AUTHZ_MAJOR, AUTHZ_MINOR);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_address(&authorization, "localAddress", local);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_address(&authorization, "remoteAddress", remote);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authorization, "serviceDescription", service_description);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&authorization, "authType", auth_type);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authorization, "domain", session_info->info->domain_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authorization, "account", session_info->info->account_name);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_sid(
	    &authorization, "sid", &session_info->security_token->sids[0]);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_guid(
	    &authorization, "sessionId", &session_info->unique_session_token);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authorization, "logonServer", session_info->info->logon_server);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(
	    &authorization, "transportProtection", transport_protection);
	if (rc != 0) {
		goto failure;
	}

	snprintf(account_flags,
		 sizeof(account_flags),
		 "0x%08X",
		 session_info->info->acct_flags);
	rc = json_add_string(&authorization, "accountFlags", account_flags);
	if (rc != 0) {
		goto failure;
	}

	wrapper = json_new_object();
	if (json_is_invalid(&wrapper)) {
		goto failure;
	}
	rc = json_add_timestamp(&wrapper);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_string(&wrapper, "type", AUTHZ_JSON_TYPE);
	if (rc != 0) {
		goto failure;
	}
	rc = json_add_object(&wrapper, AUTHZ_JSON_TYPE, &authorization);
	if (rc != 0) {
		goto failure;
	}

	log_json(msg_ctx,
		 lp_ctx,
		 &wrapper,
		 DBGC_AUTH_AUDIT_JSON,
		 debug_level);
	json_free(&wrapper);
	return;
failure:
	/*
	 * On a failure authorization will not have been added to wrapper so it
	 * needs to be freed to avoid a leak.
	 *
	 */
	json_free(&authorization);
	json_free(&wrapper);
	DBG_ERR("Unable to log Authentication event JSON audit message\n");
}

#else

static void log_no_json(struct imessaging_context *msg_ctx,
                        struct loadparm_context *lp_ctx)
{
	if (msg_ctx && lp_ctx && lpcfg_auth_event_notification(lp_ctx)) {
		static bool auth_event_logged = false;
		if (auth_event_logged == false) {
			auth_event_logged = true;
			DBG_ERR("auth event notification = true but Samba was "
				"not compiled with jansson\n");
		}
	} else {
		static bool json_logged = false;
		if (json_logged == false) {
			json_logged = true;
			DBG_NOTICE("JSON auth logs not available unless "
				   "compiled with jansson\n");
		}
	}

	return;
}

static void log_authentication_event_json(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct timeval *start_time,
	const struct auth_usersupplied_info *ui,
	NTSTATUS status,
	const char *domain_name,
	const char *account_name,
	struct dom_sid *sid,
	enum event_id_type event_id,
	int debug_level)
{
	log_no_json(msg_ctx, lp_ctx);
	return;
}

static void log_successful_authz_event_json(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct tsocket_address *remote,
	const struct tsocket_address *local,
	const char *service_description,
	const char *auth_type,
	const char *transport_protection,
	struct auth_session_info *session_info,
	int debug_level)
{
	log_no_json(msg_ctx, lp_ctx);
	return;
}

#endif

/*
 * Determine the type of the password supplied for the
 * authorisation attempt.
 *
 */
static const char* get_password_type(const struct auth_usersupplied_info *ui)
{

	const char *password_type = NULL;

	if (ui->password_type != NULL) {
		password_type = ui->password_type;
	} else if (ui->auth_description != NULL &&
		   strncmp("ServerAuthenticate", ui->auth_description, 18) == 0)
	{
		if (ui->netlogon_trust_account.negotiate_flags
		    & NETLOGON_NEG_SUPPORTS_AES) {
			password_type = "HMAC-SHA256";
		} else if (ui->netlogon_trust_account.negotiate_flags
		           & NETLOGON_NEG_STRONG_KEYS) {
			password_type = "HMAC-MD5";
		} else {
			password_type = "DES";
		}
	} else if (ui->password_state == AUTH_PASSWORD_RESPONSE &&
		   (ui->logon_parameters & MSV1_0_ALLOW_MSVCHAPV2) &&
		   ui->password.response.nt.length == 24) {
		password_type = "MSCHAPv2";
	} else if ((ui->logon_parameters & MSV1_0_CLEARTEXT_PASSWORD_SUPPLIED)
		   || (ui->password_state == AUTH_PASSWORD_PLAIN)) {
		password_type = "Plaintext";
	} else if (ui->password_state == AUTH_PASSWORD_HASH) {
		password_type = "Supplied-NT-Hash";
	} else if (ui->password_state == AUTH_PASSWORD_RESPONSE
		   && ui->password.response.nt.length > 24) {
		password_type = "NTLMv2";
	} else if (ui->password_state == AUTH_PASSWORD_RESPONSE
		   && ui->password.response.nt.length == 24) {
		password_type = "NTLMv1";
	} else if (ui->password_state == AUTH_PASSWORD_RESPONSE
		   && ui->password.response.lanman.length == 24) {
		password_type = "LANMan";
	} else if (ui->password_state == AUTH_PASSWORD_RESPONSE
		   && ui->password.response.nt.length == 0
		   && ui->password.response.lanman.length == 0) {
		password_type = "No-Password";
	}
	return password_type;
}

/*
 * Write a human readable authentication log entry.
 *
 */
static void log_authentication_event_human_readable(
	const struct auth_usersupplied_info *ui,
	NTSTATUS status,
	const char *domain_name,
	const char *account_name,
	struct dom_sid *sid,
	int debug_level)
{
	TALLOC_CTX *frame = NULL;

	const char *ts = NULL;		   /* formatted current time      */
	char *remote = NULL;		   /* formatted remote host       */
	char *local = NULL;		   /* formatted local host        */
	char *nl = NULL;		   /* NETLOGON details if present */
	char *trust_computer_name = NULL;
	char *trust_account_name = NULL;
	char *logon_line = NULL;
	const char *password_type = NULL;

	frame = talloc_stackframe();

	password_type = get_password_type(ui);
	/* Get the current time */
        ts = audit_get_timestamp(frame);

	/* Only log the NETLOGON details if they are present */
	if (ui->netlogon_trust_account.computer_name ||
	    ui->netlogon_trust_account.account_name) {
		trust_computer_name = log_escape(frame,
			ui->netlogon_trust_account.computer_name);
		trust_account_name  = log_escape(frame,
			ui->netlogon_trust_account.account_name);
		nl = talloc_asprintf(frame,
			" NETLOGON computer [%s] trust account [%s]",
			trust_computer_name, trust_account_name);
	}

	remote = tsocket_address_string(ui->remote_host, frame);
	local = tsocket_address_string(ui->local_host, frame);

	if (NT_STATUS_IS_OK(status)) {
		struct dom_sid_buf sid_buf;

		logon_line = talloc_asprintf(frame,
					     " became [%s]\\[%s] [%s].",
					     log_escape(frame, domain_name),
					     log_escape(frame, account_name),
					     dom_sid_str_buf(sid, &sid_buf));
	} else {
		logon_line = talloc_asprintf(
				frame,
				" mapped to [%s]\\[%s].",
				log_escape(frame, ui->mapped.domain_name),
				log_escape(frame, ui->mapped.account_name));
	}

	DEBUGC(DBGC_AUTH_AUDIT, debug_level,
	       ("Auth: [%s,%s] user [%s]\\[%s]"
		" at [%s] with [%s] status [%s]"
		" workstation [%s] remote host [%s]"
		"%s local host [%s]"
		" %s\n",
		ui->service_description,
		ui->auth_description,
		log_escape(frame, ui->client.domain_name),
		log_escape(frame, ui->client.account_name),
		ts,
		password_type,
		nt_errstr(status),
		log_escape(frame, ui->workstation_name),
		remote,
		logon_line,
		local,
		nl ? nl : ""
	));

	talloc_free(frame);
}

/*
 * Log details of an authentication attempt.
 * Successful and unsuccessful attempts are logged.
 *
 * NOTE: msg_ctx and lp_ctx is optional, but when supplied allows streaming the
 * authentication events over the message bus.
 */
void log_authentication_event(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct timeval *start_time,
	const struct auth_usersupplied_info *ui,
	NTSTATUS status,
	const char *domain_name,
	const char *account_name,
	struct dom_sid *sid)
{
	/* set the log level */
	int debug_level = AUTH_FAILURE_LEVEL;
	enum event_id_type event_id = EVT_ID_UNSUCCESSFUL_LOGON;

	if (NT_STATUS_IS_OK(status)) {
		debug_level = AUTH_SUCCESS_LEVEL;
		event_id = EVT_ID_SUCCESSFUL_LOGON;
		if (dom_sid_equal(sid, &global_sid_Anonymous)) {
			debug_level = AUTH_ANONYMOUS_LEVEL;
		}
	}

	if (CHECK_DEBUGLVLC(DBGC_AUTH_AUDIT, debug_level)) {
		log_authentication_event_human_readable(ui,
							status,
							domain_name,
							account_name,
							sid,
							debug_level);
	}
	if (CHECK_DEBUGLVLC(DBGC_AUTH_AUDIT_JSON, debug_level) ||
	    (msg_ctx && lp_ctx && lpcfg_auth_event_notification(lp_ctx))) {
		log_authentication_event_json(msg_ctx,
					      lp_ctx,
					      start_time,
					      ui,
					      status,
					      domain_name,
					      account_name,
					      sid,
					      event_id,
					      debug_level);
	}
}



/*
 * Log details of a successful authorization to a service,
 * in a human readable format.
 *
 */
static void log_successful_authz_event_human_readable(
	const struct tsocket_address *remote,
	const struct tsocket_address *local,
	const char *service_description,
	const char *auth_type,
	struct auth_session_info *session_info,
	int debug_level)
{
	TALLOC_CTX *frame = NULL;

	const char *ts = NULL;       /* formatted current time      */
	char *remote_str = NULL;     /* formatted remote host       */
	char *local_str = NULL;      /* formatted local host        */
	struct dom_sid_buf sid_buf;

	frame = talloc_stackframe();

	/* Get the current time */
        ts = audit_get_timestamp(frame);

	remote_str = tsocket_address_string(remote, frame);
	local_str = tsocket_address_string(local, frame);

	DEBUGC(DBGC_AUTH_AUDIT, debug_level,
	       ("Successful AuthZ: [%s,%s] user [%s]\\[%s] [%s]"
		" at [%s]"
		" Remote host [%s]"
		" local host [%s]\n",
		service_description,
		auth_type,
		log_escape(frame, session_info->info->domain_name),
		log_escape(frame, session_info->info->account_name),
		dom_sid_str_buf(&session_info->security_token->sids[0],
				&sid_buf),
		ts,
		remote_str,
		local_str));

	talloc_free(frame);
}

/*
 * Log details of a successful authorization to a service.
 *
 * Only successful authorizations are logged.  For clarity:
 * - NTLM bad passwords will be recorded by log_authentication_event
 * - Kerberos decrypt failures need to be logged in gensec_gssapi et al
 *
 * The service may later refuse authorization due to an ACL.
 *
 * NOTE: msg_ctx and lp_ctx is optional, but when supplied allows streaming the
 * authentication events over the message bus.
 */
void log_successful_authz_event(
	struct imessaging_context *msg_ctx,
	struct loadparm_context *lp_ctx,
	const struct tsocket_address *remote,
	const struct tsocket_address *local,
	const char *service_description,
	const char *auth_type,
	const char *transport_protection,
	struct auth_session_info *session_info)
{
	int debug_level = AUTHZ_SUCCESS_LEVEL;

	/* set the log level */
	if (security_token_is_anonymous(session_info->security_token)) {
		debug_level = AUTH_ANONYMOUS_LEVEL;
	}

	if (CHECK_DEBUGLVLC(DBGC_AUTH_AUDIT, debug_level)) {
		log_successful_authz_event_human_readable(remote,
							  local,
							  service_description,
							  auth_type,
							  session_info,
							  debug_level);
	}
	if (CHECK_DEBUGLVLC(DBGC_AUTH_AUDIT_JSON, debug_level) ||
	    (msg_ctx && lp_ctx && lpcfg_auth_event_notification(lp_ctx))) {
		log_successful_authz_event_json(msg_ctx, lp_ctx,
						remote,
						local,
						service_description,
						auth_type,
						transport_protection,
						session_info,
						debug_level);
	}
}