cf5c2718af
Improve the built-in access checks for sesman/sesexec:- - Group existence is checked for at login-time rather than program start time - The name of the group is now included in the message Also, check for UID == 0 when checking for root, rather than just checking the name (which might be an alias)
186 lines
4.9 KiB
C
186 lines
4.9 KiB
C
/**
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* xrdp: A Remote Desktop Protocol server.
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*
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* Copyright (C) Jay Sorg 2004-2015
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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*
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* @file sesman_access.c
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* @brief User access control code
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* @author Simone Fedele
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*
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*/
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#if defined(HAVE_CONFIG_H)
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#include <config_ac.h>
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#endif
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#include <stdio.h>
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#include "arch.h"
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#include "sesman_access.h"
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#include "sesman_config.h"
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#include "log.h"
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#include "os_calls.h"
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/******************************************************************************/
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/**
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* Root user login check
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*
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* @param cfg_sec Sesman security config
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* @param user user name
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* @return 0 if user is root and root accesses are not allowed
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*/
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static int
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root_login_check(const struct config_security *cfg_sec,
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const char *user)
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{
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int rv = 0;
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if (cfg_sec->allow_root)
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{
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rv = 1;
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}
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else
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{
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// Check the UID of the user isn't 0
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int uid;
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if (g_getuser_info_by_name(user, &uid, NULL, NULL, NULL, NULL) != 0)
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{
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LOG(LOG_LEVEL_ERROR, "Can't get UID for user %s", user);
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}
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else if (0 == uid)
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{
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LOG(LOG_LEVEL_ERROR,
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"ROOT login attempted, but root login is disabled");
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}
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else
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{
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rv = 1;
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}
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}
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return rv;
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}
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/******************************************************************************/
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/**
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* Common access control for group checks
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* @param group Group name
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* @param param Where group comes from (e.g. "TerminalServerUsers")
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* @param always_check_group 0 if a missing group allows a login
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* @param user Username
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* @return != 0 if the access is allowed */
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static int
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access_login_allowed_common(const char *group, const char *param,
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int always_check_group,
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const char *user)
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{
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int rv = 0;
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int gid;
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int ok;
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if (group == NULL || group[0] == '\0')
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{
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/* Group is not defined. Default access depends on whether
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* we must have the group or not */
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if (always_check_group)
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{
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LOG(LOG_LEVEL_ERROR,
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"%s group is not defined. Access denied for %s",
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param, user);
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}
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else
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{
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LOG(LOG_LEVEL_INFO,
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"%s group is not defined. Access granted for %s",
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param, user);
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rv = 1;
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}
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}
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else if (g_getgroup_info(group, &gid) != 0)
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{
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/* Group is defined but doesn't exist. Default access depends
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* on whether we must have the group or not */
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if (always_check_group)
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{
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LOG(LOG_LEVEL_ERROR,
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"%s group %s doesn't exist. Access denied for %s",
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param, group, user);
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}
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else
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{
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LOG(LOG_LEVEL_INFO,
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"%s group %s doesn't exist. Access granted for %s",
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param, group, user);
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rv = 1;
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}
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}
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else if (0 != g_check_user_in_group(user, gid, &ok))
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{
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LOG(LOG_LEVEL_ERROR, "Error checking %s group %s. "
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"Access denied for %s", param, group, user);
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}
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else if (!ok)
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{
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LOG(LOG_LEVEL_ERROR, "User %s is not in %s group %s. Access denied",
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user, param, group);
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}
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else
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{
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LOG(LOG_LEVEL_INFO, "User %s is in %s group %s. Access granted",
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user, param, group);
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rv = 1;
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}
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return rv;
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}
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/******************************************************************************/
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int
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access_login_allowed(const struct config_security *cfg_sec, const char *user)
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{
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int rv = 0;
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if (root_login_check(cfg_sec, user))
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{
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rv = access_login_allowed_common(cfg_sec->ts_users,
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"TerminalServerUsers",
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cfg_sec->ts_always_group_check,
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user);
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}
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return rv;
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}
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/******************************************************************************/
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int
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access_login_mng_allowed(const struct config_security *cfg_sec,
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const char *user)
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{
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int rv = 0;
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if (root_login_check(cfg_sec, user))
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{
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rv = access_login_allowed_common(cfg_sec->ts_admins,
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"TerminalServerAdmins",
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1,
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user);
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}
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return rv;
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}
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