/*
 * Copyright (c) 2019 The DragonFly Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>

#include <string.h>
#include <unistd.h>

#include "packet.h"
#include "sshbuf.h"
#include "sshkey.h"
#include "hostfile.h"
#include "auth.h"
#include "auth-options.h"

int
sys_auth_passwd(struct ssh *ssh, const char *password)
{
	Authctxt *authctxt = ssh->authctxt;
	struct passwd *pw = authctxt->pw;
	char *encrypted_password, *salt = NULL;

	/* Just use the supplied fake password if authctxt is invalid */
	char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd;

	if (pw_password == NULL)
		return 0;

	/* Check for users with no password. */
	if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0)
		return (1);

	/*
	 * Encrypt the candidate password using the proper salt using
	 * <unistd.h> crypt() version from libcrypt.
	 * The OpenSSH xcrypt() is using DES_crypt().
	 */
	if (authctxt->valid && pw_password[0] && pw_password[1])
		salt = pw_password;
	else
		salt = "xx";
	encrypted_password = crypt(password, salt);

	/*
	 * Authentication is accepted if the encrypted passwords
	 * are identical.
	 */
	return encrypted_password != NULL &&
	    strcmp(encrypted_password, pw_password) == 0;
}