mariadb/plugin/auth_gssapi/server_plugin.cc
Vladislav Vaintroub 7ebabea5d3 MDEV-23959 GSSAPI plugin - support AD or local group name , and SIDs on Windows
Support membership tests in SSPI with special prefix form

CREATE USER u IDENTIFIED WITH gssapi AS "GROUP:<group_name>"
or
CREATE USER u IDENTIFIED WITH gssapi AS "SID:<sid>"

If user is created as one of the above, after successful SSPI handshake,
this will happen

1) If "GROUP:" prefix is used, then <group_name> is translated to SID
using LookupAccountName() API

2) SSPI user is checked for  SID membership with
ImpersonateSecurityContext() and CheckMembership() APIs

Note, that it <group>/<sid> do not need strictly to refer to an actual
group.
Identity test is also supported, e.g  "GROUP:<users_name>" or
"SID:<user_sid>" will work too.


Well-known SIDs (in SDDL syntax) appear to be supported such as
"SID:WD" will refer to World/Everyone (== "SID:S-1-1-0")
or
"SID:BA" will refer to Administrators (== "SID:S-1-5-32-544")

In UAC environments, for successful checks against Administrators group,
elevation(Run As Administrator) might be necessary, since CheckMembership()
needs groups to be marked as enabled in the token group list.
2021-01-27 14:38:00 +01:00

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/* Copyright (c) 2015, Shuang Qiu, Robbie Harwood,
Vladislav Vaintroub & MariaDB Corporation
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 HOLDER 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.
*/
/**
@file
GSSAPI authentication plugin, server side
*/
typedef unsigned long long my_ulonglong;
#include <stdlib.h>
#include <mysqld_error.h>
#include <typelib.h>
#include <mysql/plugin_auth.h>
#include "string.h"
#include "server_plugin.h"
#include "common.h"
/* First packet sent from server to client, contains srv_principal_name\0mech\0 */
static char first_packet[PRINCIPAL_NAME_MAX + MECH_NAME_MAX +2];
static int first_packet_len;
/*
Target name in GSSAPI/SSPI , for Kerberos it is service principal name
(often user principal name of the server user will work)
*/
char *srv_principal_name;
char *srv_keytab_path;
const char *srv_mech_name="";
unsigned long srv_mech;
/**
The main server function of the GSSAPI plugin.
*/
static int gssapi_auth(MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *auth_info)
{
/* Send first packet with target name and mech name */
if (vio->write_packet(vio, (unsigned char *)first_packet, first_packet_len))
return CR_ERROR;
return auth_server(vio, auth_info);
}
static int initialize_plugin(void *unused)
{
int rc;
rc = plugin_init();
if (rc)
return rc;
strcpy(first_packet, srv_principal_name);
strcpy(first_packet + strlen(srv_principal_name) + 1,srv_mech_name);
first_packet_len = (int)(strlen(srv_principal_name) + strlen(srv_mech_name) + 2);
return 0;
}
static int deinitialize_plugin(void *unused)
{
return plugin_deinit();
}
#ifdef PLUGIN_GSSAPI
/* system variable */
static MYSQL_SYSVAR_STR(keytab_path, srv_keytab_path,
PLUGIN_VAR_RQCMDARG|PLUGIN_VAR_READONLY,
"Keytab file path for Kerberos authentication",
NULL,
NULL,
"");
#endif
static MYSQL_SYSVAR_STR(principal_name, srv_principal_name,
PLUGIN_VAR_RQCMDARG|PLUGIN_VAR_READONLY,
"GSSAPI target name - service principal name for Kerberos authentication.",
NULL,
NULL,
"");
#ifdef PLUGIN_SSPI
static const char* mech_names[] = {
"Kerberos",
"Negotiate",
"",
NULL
};
static TYPELIB mech_name_typelib = {
3,
"mech_name_typelib",
mech_names,
NULL
};
static MYSQL_SYSVAR_ENUM(mech_name, srv_mech,
PLUGIN_VAR_RQCMDARG|PLUGIN_VAR_READONLY,
"GSSAPI mechanism",
NULL,
NULL,
2,&mech_name_typelib);
#endif
static struct st_mysql_sys_var *system_variables[]= {
MYSQL_SYSVAR(principal_name),
#ifdef PLUGIN_SSPI
MYSQL_SYSVAR(mech_name),
#endif
#ifdef PLUGIN_GSSAPI
MYSQL_SYSVAR(keytab_path),
#endif
NULL
};
/* Register authentication plugin */
static struct st_mysql_auth server_handler= {
MYSQL_AUTHENTICATION_INTERFACE_VERSION,
"auth_gssapi_client",
gssapi_auth, NULL, NULL
};
maria_declare_plugin(gssapi_server)
{
MYSQL_AUTHENTICATION_PLUGIN,
&server_handler,
"gssapi",
"Shuang Qiu, Robbie Harwood, Vladislav Vaintroub",
"Plugin for GSSAPI/SSPI based authentication.",
PLUGIN_LICENSE_BSD,
initialize_plugin,
deinitialize_plugin, /* destructor */
0x0100, /* version */
NULL, /* status variables */
system_variables, /* system variables */
"1.0",
MariaDB_PLUGIN_MATURITY_STABLE
}
maria_declare_plugin_end;