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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) 2002-2005 OpenVPN Solutions LLC <info@openvpn.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 file implements a simple OpenVPN plugin module which
+ * will examine the username/password provided by a client,
+ * and make an accept/deny determination. Will run
+ * on Windows or *nix.
+ *
+ * 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 openvpn_plugin_handle_t
+openvpn_plugin_open_v1 (unsigned int *type_mask, const char *argv[], const char *envp[])
+{
+ struct plugin_context *context;
+
+ /*
+ * 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";
+
+ /*
+ * We are only interested in intercepting the
+ * --auth-user-pass-verify callback.
+ */
+ *type_mask = OPENVPN_PLUGIN_MASK (OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY);
+
+ return (openvpn_plugin_handle_t) context;
+}
+
+OPENVPN_EXPORT int
+openvpn_plugin_func_v1 (openvpn_plugin_handle_t handle, const int type, const char *argv[], const char *envp[])
+{
+ struct plugin_context *context = (struct plugin_context *) handle;
+
+ /* get username/password from envp string array */
+ const char *username = get_env ("username", envp);
+ const char *password = get_env ("password", envp);
+
+ /* check entered username/password against what we require */
+ if (username && !strcmp (username, context->username)
+ && password && !strcmp (password, context->password))
+ return OPENVPN_PLUGIN_FUNC_SUCCESS;
+ else
+ return OPENVPN_PLUGIN_FUNC_ERROR;
+}
+
+OPENVPN_EXPORT void
+openvpn_plugin_close_v1 (openvpn_plugin_handle_t handle)
+{
+ struct plugin_context *context = (struct plugin_context *) handle;
+ free (context);
+}