auth.c - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * Copyright (c) 2000 Markus Friedl. 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 AUTHOR ``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 AUTHOR 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"
 RCSID("$OpenBSD: auth.c,v 1.16 2001/02/04 15:32:22 stevesk Exp $");

 #ifdef HAVE_LOGIN_H
 #include <login.h>
 #endif
 #if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
 #include <shadow.h>
 #endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */

 #include "xmalloc.h"
 #include "match.h"
 #include "groupaccess.h"
 #include "log.h"
 #include "servconf.h"
 #include "auth.h"
 #include "auth-options.h"
 #include "canohost.h"

 /* import */
 extern ServerOptions options;

 /*
  * Check if the user is allowed to log in via ssh. If user is listed
  * in DenyUsers or one of user's groups is listed in DenyGroups, false
  * will be returned. If AllowUsers isn't empty and user isn't listed
  * there, or if AllowGroups isn't empty and one of user's groups isn't
  * listed there, false will be returned.
  * If the user's shell is not executable, false will be returned.
  * Otherwise true is returned.
  */
 int
 allowed_user(struct passwd * pw)
 {
 	struct stat st;
 	char *shell;
 	int i;
 #ifdef WITH_AIXAUTHENTICATE
 	char *loginmsg;
 #endif /* WITH_AIXAUTHENTICATE */
 #if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
 	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
 	struct spwd *spw;

 	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
 	if (!pw || !pw->pw_name)
 		return 0;

 	spw = getspnam(pw->pw_name);
 	if (spw != NULL) {
 		int days = time(NULL) / 86400;

 		/* Check account expiry */
 		if ((spw->sp_expire >= 0) && (days > spw->sp_expire))
 			return 0;

 		/* Check password expiry */
 		if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) &&
 		    (days > (spw->sp_lstchg + spw->sp_max)))
 			return 0;
 	}
 #else
 	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
 	if (!pw || !pw->pw_name)
 		return 0;
 #endif

 	/*
 	 * Get the shell from the password data.  An empty shell field is
 	 * legal, and means /bin/sh.
 	 */
 	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;

 	/* deny if shell does not exists or is not executable */
 	if (stat(shell, &st) != 0)
 		return 0;
 	if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
 		return 0;

 	/* Return false if user is listed in DenyUsers */
 	if (options.num_deny_users > 0) {
 		for (i = 0; i < options.num_deny_users; i++)
 			if (match_pattern(pw->pw_name, options.deny_users[i]))
 				return 0;
 	}
 	/* Return false if AllowUsers isn't empty and user isn't listed there */
 	if (options.num_allow_users > 0) {
 		for (i = 0; i < options.num_allow_users; i++)
 			if (match_pattern(pw->pw_name, options.allow_users[i]))
 				break;
 		/* i < options.num_allow_users iff we break for loop */
 		if (i >= options.num_allow_users)
 			return 0;
 	}
 	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
 		/* Get the user's group access list (primary and supplementary) */
 		if (ga_init(pw->pw_name, pw->pw_gid) == 0)
 			return 0;

 		/* Return false if one of user's groups is listed in DenyGroups */
 		if (options.num_deny_groups > 0)
 			if (ga_match(options.deny_groups,
 			    options.num_deny_groups)) {
 				ga_free();
 				return 0;
 			}
 		/*
 		 * Return false if AllowGroups isn't empty and one of user's groups
 		 * isn't listed there
 		 */
 		if (options.num_allow_groups > 0)
 			if (!ga_match(options.allow_groups,
 			    options.num_allow_groups)) {
 				ga_free();
 				return 0;
 			}
 		ga_free();
 	}

 #ifdef WITH_AIXAUTHENTICATE
 	if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
 		if (loginmsg && *loginmsg) {
 			/* Remove embedded newlines (if any) */
 			char *p;
 			for (p = loginmsg; *p; p++) {
 				if (*p == '\n')
 					*p = ' ';
 			}
 			/* Remove trailing newline */
 			*--p = '\0';
 			log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
 		}
 		return 0;
 	}
 #endif /* WITH_AIXAUTHENTICATE */

 	/* We found no reason not to let this user try to log on... */
 	return 1;
 }

 Authctxt *
 authctxt_new(void)
 {
 	Authctxt *authctxt = xmalloc(sizeof(*authctxt));
 	memset(authctxt, 0, sizeof(*authctxt));
 	return authctxt;
 }

 struct passwd *
 pwcopy(struct passwd *pw)
 {
 	struct passwd *copy = xmalloc(sizeof(*copy));
 	memset(copy, 0, sizeof(*copy));
 	copy->pw_name = xstrdup(pw->pw_name);
 	copy->pw_passwd = xstrdup(pw->pw_passwd);
 	copy->pw_uid = pw->pw_uid;
 	copy->pw_gid = pw->pw_gid;
 #ifdef HAVE_PW_CLASS_IN_PASSWD
 	copy->pw_class = xstrdup(pw->pw_class);
 #endif
 	copy->pw_dir = xstrdup(pw->pw_dir);
 	copy->pw_shell = xstrdup(pw->pw_shell);
 	return copy;
 }

 void
 auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
 {
 	void (*authlog) (const char *fmt,...) = verbose;
 	char *authmsg;

 	/* Raise logging level */
 	if (authenticated == 1 ||
 	    !authctxt->valid ||
 	    authctxt->failures >= AUTH_FAIL_LOG ||
 	    strcmp(method, "password") == 0)
 		authlog = log;

 	if (authctxt->postponed)
 		authmsg = "Postponed";
 	else
 		authmsg = authenticated ? "Accepted" : "Failed";

 	authlog("%s %s for %s%.100s from %.200s port %d%s",
 	    authmsg,
 	    method,
 	    authctxt->valid ? "" : "illegal user ",
 	    authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user,
 	    get_remote_ipaddr(),
 	    get_remote_port(),
 	    info);
 }

 /*
  * Check if the user is logging in as root and root logins are disallowed.
  * Note that root login is _allways_ allowed for forced commands.
  */
 int
 auth_root_allowed(void)
 {
 	if (options.permit_root_login)
 		return 1;
 	if (forced_command) {
 		log("Root login accepted for forced command.");
 		return 1;
 	} else {
 		log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
 		return 0;
 	}
 }
	/*
	* Copyright (c) 2000 Markus Friedl. 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 AUTHOR ``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 AUTHOR 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"
	RCSID("$OpenBSD: auth.c,v 1.16 2001/02/04 15:32:22 stevesk Exp $");

	#ifdef HAVE_LOGIN_H
	#include <login.h>
	#endif
	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	#include <shadow.h>
	#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */

	#include "xmalloc.h"
	#include "match.h"
	#include "groupaccess.h"
	#include "log.h"
	#include "servconf.h"
	#include "auth.h"
	#include "auth-options.h"
	#include "canohost.h"

	/* import */
	extern ServerOptions options;

	/*
	* Check if the user is allowed to log in via ssh. If user is listed
	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	* will be returned. If AllowUsers isn't empty and user isn't listed
	* there, or if AllowGroups isn't empty and one of user's groups isn't
	* listed there, false will be returned.
	* If the user's shell is not executable, false will be returned.
	* Otherwise true is returned.
	*/
	int
	allowed_user(struct passwd * pw)
	{
	struct stat st;
	char *shell;
	int i;
	#ifdef WITH_AIXAUTHENTICATE
	char *loginmsg;
	#endif /* WITH_AIXAUTHENTICATE */
	#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	struct spwd *spw;

	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	if (!pw \|\| !pw->pw_name)
	return 0;

	spw = getspnam(pw->pw_name);
	if (spw != NULL) {
	int days = time(NULL) / 86400;

	/* Check account expiry */
	if ((spw->sp_expire >= 0) && (days > spw->sp_expire))
	return 0;

	/* Check password expiry */
	if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) &&
	(days > (spw->sp_lstchg + spw->sp_max)))
	return 0;
	}
	#else
	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	if (!pw \|\| !pw->pw_name)
	return 0;
	#endif

	/*
	* Get the shell from the password data. An empty shell field is
	* legal, and means /bin/sh.
	*/
	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;

	/* deny if shell does not exists or is not executable */
	if (stat(shell, &st) != 0)
	return 0;
	if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP))))
	return 0;

	/* Return false if user is listed in DenyUsers */
	if (options.num_deny_users > 0) {
	for (i = 0; i < options.num_deny_users; i++)
	if (match_pattern(pw->pw_name, options.deny_users[i]))
	return 0;
	}
	/* Return false if AllowUsers isn't empty and user isn't listed there */
	if (options.num_allow_users > 0) {
	for (i = 0; i < options.num_allow_users; i++)
	if (match_pattern(pw->pw_name, options.allow_users[i]))
	break;
	/* i < options.num_allow_users iff we break for loop */
	if (i >= options.num_allow_users)
	return 0;
	}
	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
	/* Get the user's group access list (primary and supplementary) */
	if (ga_init(pw->pw_name, pw->pw_gid) == 0)
	return 0;

	/* Return false if one of user's groups is listed in DenyGroups */
	if (options.num_deny_groups > 0)
	if (ga_match(options.deny_groups,
	options.num_deny_groups)) {
	ga_free();
	return 0;
	}
	/*
	* Return false if AllowGroups isn't empty and one of user's groups
	* isn't listed there
	*/
	if (options.num_allow_groups > 0)
	if (!ga_match(options.allow_groups,
	options.num_allow_groups)) {
	ga_free();
	return 0;
	}
	ga_free();
	}

	#ifdef WITH_AIXAUTHENTICATE
	if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
	if (loginmsg && *loginmsg) {
	/* Remove embedded newlines (if any) */
	char *p;
	for (p = loginmsg; *p; p++) {
	if (*p == '\n')
	*p = ' ';
	}
	/* Remove trailing newline */
	*--p = '\0';
	log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
	}
	return 0;
	}
	#endif /* WITH_AIXAUTHENTICATE */

	/* We found no reason not to let this user try to log on... */
	return 1;
	}

	Authctxt *
	authctxt_new(void)
	{
	Authctxt authctxt = xmalloc(sizeof(authctxt));
	memset(authctxt, 0, sizeof(*authctxt));
	return authctxt;
	}

	struct passwd *
	pwcopy(struct passwd *pw)
	{
	struct passwd copy = xmalloc(sizeof(copy));
	memset(copy, 0, sizeof(*copy));
	copy->pw_name = xstrdup(pw->pw_name);
	copy->pw_passwd = xstrdup(pw->pw_passwd);
	copy->pw_uid = pw->pw_uid;
	copy->pw_gid = pw->pw_gid;
	#ifdef HAVE_PW_CLASS_IN_PASSWD
	copy->pw_class = xstrdup(pw->pw_class);
	#endif
	copy->pw_dir = xstrdup(pw->pw_dir);
	copy->pw_shell = xstrdup(pw->pw_shell);
	return copy;
	}

	void
	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	{
	void (authlog) (const char fmt,...) = verbose;
	char *authmsg;

	/* Raise logging level */
	if (authenticated == 1 \|\|
	!authctxt->valid \|\|
	authctxt->failures >= AUTH_FAIL_LOG \|\|
	strcmp(method, "password") == 0)
	authlog = log;

	if (authctxt->postponed)
	authmsg = "Postponed";
	else
	authmsg = authenticated ? "Accepted" : "Failed";

	authlog("%s %s for %s%.100s from %.200s port %d%s",
	authmsg,
	method,
	authctxt->valid ? "" : "illegal user ",
	authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user,
	get_remote_ipaddr(),
	get_remote_port(),
	info);
	}

	/*
	* Check if the user is logging in as root and root logins are disallowed.
	* Note that root login is _allways_ allowed for forced commands.
	*/
	int
	auth_root_allowed(void)
	{
	if (options.permit_root_login)
	return 1;
	if (forced_command) {
	log("Root login accepted for forced command.");
	return 1;
	} else {
	log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
	return 0;
	}
	}