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Added a simple plug-in demonstrating the v3 plug-in API.

Browse source 
To build the plug-in, do ./build log_v3 in the plugin/examples directory.

This plug-in can be tested by running an OpenVPN server like this:

 # ./openvpn --plugin plugin/examples/log_v3.so --dev tun \
             --server 192.168.240.0 255.255.255.0 --ca sample-keys/ca.crt \
             --cert sample-keys/server.crt --key sample-keys/server.key \
             --dh sample-keys/dh1024.pem

The client can be started like this:

 # ./openvpn --client --remote localhost --ca sample-keys/ca.crt \
             --cert sample-keys/client.crt --key sample-keys/client.key \
             --dev tun --nobind --auth-user-pass

This plug-in will only log arguments and environment variables it receives
during all the different plug-in phases OpenVPN currently supports.  It will
also parse the X509 certificate information given during the TLS_VERIFY phase.

Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>
Acked-by: James Yonan <james@openvpn.net>
This commit is contained in:
David Sommerseth 2010-12-10 01:20:43 +01:00 committed by David Sommerseth
parent 81c97a5e22
commit 10960e3cd3
1 changed files with 245 additions and 0 deletions
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245
plugin/examples/log_v3.c Normal file
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/*
* 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) 2002-2009 OpenVPN Technologies, 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 (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 apiver,
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( apiver != OPENVPN_PLUGIN_VERSION ) {
return OPENVPN_PLUGIN_FUNC_ERROR;
}
/* 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;
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;
buf = (unsigned char *)1; /* bug in OpenSSL 0.9.6b ASN1_STRING_to_UTF8 requires this workaround */
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);
}