/*****************************************************************************\
 *  jwt.c - Slurm REST auth JWT plugin
 *****************************************************************************
 *  Copyright (C) SchedMD LLC.
 *
 *  This file is part of Slurm, a resource management program.
 *  For details, see <https://slurm.schedmd.com/>.
 *  Please also read the included file: DISCLAIMER.
 *
 *  Slurm 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 2 of the License, or (at your option)
 *  any later version.
 *
 *  In addition, as a special exception, the copyright holders give permission
 *  to link the code of portions of this program with the OpenSSL library under
 *  certain conditions as described in each individual source file, and
 *  distribute linked combinations including the two. You must obey the GNU
 *  General Public License in all respects for all of the code used other than
 *  OpenSSL. If you modify file(s) with this exception, you may extend this
 *  exception to your version of the file(s), but you are not obligated to do
 *  so. If you do not wish to do so, delete this exception statement from your
 *  version.  If you delete this exception statement from all source files in
 *  the program, then also delete it here.
 *
 *  Slurm 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 Slurm; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA.
\*****************************************************************************/

#include "config.h"

#include <unistd.h>

#include "slurm/slurm.h"
#include "slurm/slurmdb.h"

#include "src/common/data.h"
#include "src/common/log.h"
#include "src/interfaces/auth.h"
#include "src/common/xassert.h"
#include "src/common/xmalloc.h"
#include "src/common/xstring.h"

#include "src/slurmrestd/http.h"
#include "src/slurmrestd/rest_auth.h"

/*
 * These variables are required by the generic plugin interface.  If they
 * are not found in the plugin, the plugin loader will ignore it.
 *
 * plugin_name - a string giving a human-readable description of the
 * plugin.  There is no maximum length, but the symbol must refer to
 * a valid string.
 *
 * plugin_type - a string suggesting the type of the plugin or its
 * applicability to a particular form of data or method of data handling.
 * If the low-level plugin API is used, the contents of this string are
 * unimportant and may be anything.  Slurm uses the higher-level plugin
 * interface which requires this string to be of the form
 *
 *	<application>/<method>
 *
 * where <application> is a description of the intended application of
 * the plugin (e.g., "select" for Slurm node selection) and <method>
 * is a description of how this plugin satisfies that application.  Slurm will
 * only load select plugins if the plugin_type string has a
 * prefix of "select/".
 *
 * plugin_version - an unsigned 32-bit integer containing the Slurm version
 * (major.minor.micro combined into a single number).
 */
const char plugin_name[] = "REST auth/jwt";
const char plugin_type[] = "rest_auth/jwt";
const uint32_t plugin_id = 100;
const uint32_t plugin_version = SLURM_VERSION_NUMBER;

#define MAGIC 0x221abee1
typedef struct {
	int magic;
	char *token;
	void *db_conn;
} plugin_data_t;

extern int slurm_rest_auth_p_authenticate(on_http_request_args_t *args,
					  rest_auth_context_t *ctxt)
{
	plugin_data_t *data = NULL;
	const char *key = NULL, *user_name = NULL, *bearer = NULL;
	const char *name = args->name;
	char *token = NULL;

	key = find_http_header(args->headers, HTTP_HEADER_USER_TOKEN);
	bearer = find_http_header(args->headers, HTTP_HEADER_AUTH);
	user_name = find_http_header(args->headers, HTTP_HEADER_USER_NAME);

	if (!key && !user_name && !bearer) {
		debug3("%s: [%s] skipping token authentication",
		       __func__, name);
		return ESLURM_AUTH_SKIP;
	}

	if (!key && !bearer) {
		error("%s: [%s] missing header user token: %s",
		      __func__, name, HTTP_HEADER_USER_TOKEN);
		return ESLURM_AUTH_CRED_INVALID;
	} else if (key && bearer) {
		error("%s: [%s] mutually exclusive headers %s and %s found. Rejecting ambiguous authentication request.",
		      __func__, name, HTTP_HEADER_USER_TOKEN, HTTP_HEADER_AUTH);
		return ESLURM_AUTH_CRED_INVALID;
	}

	xassert(!ctxt->user_name);
	xassert(!ctxt->plugin_data);
	xassert(!ctxt->plugin_id);

	if (key) {
		token = xstrdup(key);
	} else if (bearer) {
		if (!xstrncmp(HTTP_HEADER_AUTH_BEARER, bearer,
			      strlen(HTTP_HEADER_AUTH_BEARER))) {
			token = xstrdup(bearer +
					strlen(HTTP_HEADER_AUTH_BEARER));
		} else {
			error("%s: [%s] unexpected format for %s header: %s",
			      __func__, name, HTTP_HEADER_AUTH, bearer);
			return ESLURM_AUTH_CRED_INVALID;
		}
	}

	ctxt->plugin_data = data = xmalloc(sizeof(*data));
	data->magic = MAGIC;
	data->token = token;
	ctxt->user_name = xstrdup(user_name);

	if (user_name)
		info("[%s] attempting user_name %s token authentication pass through",
		     name, user_name);
	else if (key)
		info("[%s] attempting token authentication pass through",
		     name);
	else
		info("[%s] attempting bearer token authentication pass through",
		     name);

	return SLURM_SUCCESS;
}

extern int slurm_rest_auth_p_apply(rest_auth_context_t *context)
{
	plugin_data_t *data = context->plugin_data;

	xassert(data->magic == MAGIC);
	xassert(context->plugin_id == plugin_id);

	return auth_g_thread_config(data->token, context->user_name);
}

extern void slurm_rest_auth_p_free(rest_auth_context_t *context)
{
	plugin_data_t *data = context->plugin_data;
	xassert(data->magic == MAGIC);
	xassert(context->plugin_id == plugin_id);
	data->magic = ~MAGIC;

	if (data->db_conn)
		slurmdb_connection_close(&data->db_conn);

	xfree(data->token);
	xfree(context->plugin_data);
}

extern void *slurm_rest_auth_p_get_db_conn(rest_auth_context_t *context)
{
	plugin_data_t *data = context->plugin_data;
	xassert(context->plugin_id == plugin_id);
	xassert(data->magic == MAGIC);

	if (slurm_rest_auth_p_apply(context))
		return NULL;

	if (data->db_conn)
		return data->db_conn;

	errno = 0;
	data->db_conn = slurmdb_connection_get(NULL);

	if (!errno && data->db_conn)
		return data->db_conn;

	error("%s: unable to connect to slurmdbd: %m",
	      __func__);
	data->db_conn = NULL;

	return NULL;
}

extern void slurm_rest_auth_p_init(bool become_user)
{
	debug5("%s: REST JWT auth activated", __func__);

	if (become_user)
		fatal("%s: rest_auth/jwt must not be loaded in become_user mode",
		      __func__);
}

extern void slurm_rest_auth_p_fini(void)
{
	debug5("%s: REST JWT auth deactivated", __func__);
}
