Completely revamped the system for calling external programs and scripts:

* All external programs and scripts are now called by execve() on unix and
  CreateProcess on Windows.

* The system() function is no longer used.

* Argument lists for external programs and scripts are now built by the new
  argv_printf function which natively outputs to string arrays (i.e.
  char *argv[] lists), never truncates its output, and eliminates the security
  issues inherent in formatting and parsing command lines, and dealing with
  argument quoting.

* The --script-security directive has been added to offer policy controls on
  OpenVPN's execution of external programs and scripts.

Also added a new plugin example (openvpn/plugin/examples/log.c) that logs
information to stdout for every plugin method called by OpenVPN.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@3122 e7ae566f-a301-0410-adde-c780ea21d3b5

1 files changed, 184 insertions, 0 deletions

diff --git a/plugin/examples/log.c b/plugin/examples/log.c
new file mode 100644
index 0000000..31cbb8c
--- /dev/null
+++ b/plugin/examples/log.c
@@ -0,0 +1,184 @@
+/*
+ *  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) 2002-2008 Telethra, Inc. <sales@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 plugin is similar to simple.c, except it also logs extra information
+ * to stdout for every plugin method called by OpenVPN.
+ *
+ * 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";
+
+  /*
+   * Which callbacks to intercept.
+   */
+  *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);
+
+  return (openvpn_plugin_handle_t) context;
+}
+
+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]);
+}
+
+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;
+
+  show (type, argv, envp);
+
+  /* check entered username/password against what we require */
+  if (type == OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY)
+    {
+      /* get username/password from envp string array */
+      const char *username = get_env ("username", envp);
+      const char *password = get_env ("password", 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);
+}