/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2018 OpenVPN Inc <sales@openvpn.net>
* Copyright (C) 2010 David Sommerseth <dazo@users.sourceforge.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* This plugin is similar to simple.c, except it also logs extra information
* to stdout for every plugin method called by OpenVPN. The only difference
* between this (log_v3.c) and log.c is that this module uses the v3 plug-in
* API.
*
* See the README file for build instructions.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "openvpn-plugin.h"
/*
* Our context, where we keep our state.
*/
struct plugin_context {
const char *username;
const char *password;
};
/*
* Given an environmental variable name, search
* the envp array for its value, returning it
* if found or NULL otherwise.
*/
static const char *
get_env(const char *name, const char *envp[])
{
if (envp)
{
int i;
const int namelen = strlen(name);
for (i = 0; envp[i]; ++i)
{
if (!strncmp(envp[i], name, namelen))
{
const char *cp = envp[i] + namelen;
if (*cp == '=')
{
return cp + 1;
}
}
}
}
return NULL;
}
OPENVPN_EXPORT int
openvpn_plugin_open_v3(const int v3structver,
struct openvpn_plugin_args_open_in const *args,
struct openvpn_plugin_args_open_return *ret)
{
struct plugin_context *context = NULL;
/* Check that we are API compatible */
if (v3structver != OPENVPN_PLUGINv3_STRUCTVER)
{
printf("log_v3: ** ERROR ** Incompatible plug-in interface between this plug-in and OpenVPN\n");
return OPENVPN_PLUGIN_FUNC_ERROR;
}
if (args->ssl_api != SSLAPI_OPENSSL)
{
printf("This plug-in can only be used against OpenVPN with OpenSSL\n");
return OPENVPN_PLUGIN_FUNC_ERROR;
}
/* Print some version information about the OpenVPN process using this plug-in */
printf("log_v3: OpenVPN %s (Major: %i, Minor: %i, Patch: %s)\n",
args->ovpn_version, args->ovpn_version_major,
args->ovpn_version_minor, args->ovpn_version_patch);
/* Which callbacks to intercept. */
ret->type_mask =
OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_UP)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_DOWN)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_ROUTE_UP)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_IPCHANGE)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_TLS_VERIFY)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_CLIENT_CONNECT_V2)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_CLIENT_DISCONNECT)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_LEARN_ADDRESS)
|OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_TLS_FINAL);
/* Allocate our context */
context = (struct plugin_context *) calloc(1, sizeof(struct plugin_context));
/* Set the username/password we will require. */
context->username = "foo";
context->password = "bar";
/* Point the global context handle to our newly created context */
ret->handle = (void *) context;
return OPENVPN_PLUGIN_FUNC_SUCCESS;
}
void
show(const int type, const char *argv[], const char *envp[])
{
size_t i;
switch (type)
{
case OPENVPN_PLUGIN_UP:
printf("OPENVPN_PLUGIN_UP\n");
break;
case OPENVPN_PLUGIN_DOWN:
printf("OPENVPN_PLUGIN_DOWN\n");
break;
case OPENVPN_PLUGIN_ROUTE_UP:
printf("OPENVPN_PLUGIN_ROUTE_UP\n");
break;
case OPENVPN_PLUGIN_IPCHANGE:
printf("OPENVPN_PLUGIN_IPCHANGE\n");
break;
case OPENVPN_PLUGIN_TLS_VERIFY:
printf("OPENVPN_PLUGIN_TLS_VERIFY\n");
break;
case OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY:
printf("OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY\n");
break;
case OPENVPN_PLUGIN_CLIENT_CONNECT_V2:
printf("OPENVPN_PLUGIN_CLIENT_CONNECT_V2\n");
break;
case OPENVPN_PLUGIN_CLIENT_DISCONNECT:
printf("OPENVPN_PLUGIN_CLIENT_DISCONNECT\n");
break;
case OPENVPN_PLUGIN_LEARN_ADDRESS:
printf("OPENVPN_PLUGIN_LEARN_ADDRESS\n");
break;
case OPENVPN_PLUGIN_TLS_FINAL:
printf("OPENVPN_PLUGIN_TLS_FINAL\n");
break;
default:
printf("OPENVPN_PLUGIN_?\n");
break;
}
printf("ARGV\n");
for (i = 0; argv[i] != NULL; ++i)
printf("%d '%s'\n", (int)i, argv[i]);
printf("ENVP\n");
for (i = 0; envp[i] != NULL; ++i)
printf("%d '%s'\n", (int)i, envp[i]);
}
static void
x509_print_info(X509 *x509crt)
{
int i, n;
int fn_nid;
ASN1_OBJECT *fn;
ASN1_STRING *val;
X509_NAME *x509_name;
X509_NAME_ENTRY *ent;
const char *objbuf;
unsigned char *buf = NULL;
x509_name = X509_get_subject_name(x509crt);
n = X509_NAME_entry_count(x509_name);
for (i = 0; i < n; ++i)
{
ent = X509_NAME_get_entry(x509_name, i);
if (!ent)
{
continue;
}
fn = X509_NAME_ENTRY_get_object(ent);
if (!fn)
{
continue;
}
val = X509_NAME_ENTRY_get_data(ent);
if (!val)
{
continue;
}
fn_nid = OBJ_obj2nid(fn);
if (fn_nid == NID_undef)
{
continue;
}
objbuf = OBJ_nid2sn(fn_nid);
if (!objbuf)
{
continue;
}
if (ASN1_STRING_to_UTF8(&buf, val) < 0)
{
continue;
}
printf("X509 %s: %s\n", objbuf, (char *)buf);
OPENSSL_free(buf);
}
}
OPENVPN_EXPORT int
openvpn_plugin_func_v3(const int version,
struct openvpn_plugin_args_func_in const *args,
struct openvpn_plugin_args_func_return *retptr)
{
struct plugin_context *context = (struct plugin_context *) args->handle;
printf("\nopenvpn_plugin_func_v3() :::::>> ");
show(args->type, args->argv, args->envp);
/* Dump some X509 information if we're in the TLS_VERIFY phase */
if ((args->type == OPENVPN_PLUGIN_TLS_VERIFY) && args->current_cert)
{
printf("---- X509 Subject information ----\n");
printf("Certificate depth: %i\n", args->current_cert_depth);
x509_print_info(args->current_cert);
printf("----------------------------------\n");
}
/* check entered username/password against what we require */
if (args->type == OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY)
{
/* get username/password from envp string array */
const char *username = get_env("username", args->envp);
const char *password = get_env("password", args->envp);
if (username && !strcmp(username, context->username)
&& password && !strcmp(password, context->password))
{
return OPENVPN_PLUGIN_FUNC_SUCCESS;
}
else
{
return OPENVPN_PLUGIN_FUNC_ERROR;
}
}
else
{
return OPENVPN_PLUGIN_FUNC_SUCCESS;
}
}
OPENVPN_EXPORT void
openvpn_plugin_close_v1(openvpn_plugin_handle_t handle)
{
struct plugin_context *context = (struct plugin_context *) handle;
free(context);
}