Support asynchronous/deferred authentication in

OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY plugin handler.

See documentation in openvpn-plugin.h and example
usage in plugin/defer/simple.c.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@2969 e7ae566f-a301-0410-adde-c780ea21d3b5

5 files changed, 192 insertions, 0 deletions

diff --git a/plugin/defer/README b/plugin/defer/README
new file mode 100644
index 0000000..d8990f8
--- /dev/null
+++ b/plugin/defer/README
@@ -0,0 +1,16 @@
+OpenVPN plugin examples.
+
+Examples provided:
+
+simple.c -- using the --auth-user-pass-verify callback,
+            test deferred authentication.
+
+To build:
+
+  ./build simple (Linux/BSD/etc.)
+  ./winbuild simple (MinGW on Windows)
+
+To use in OpenVPN, add to config file:
+
+  plugin simple.so (Linux/BSD/etc.)
+  plugin simple.dll (MinGW on Windows)
diff --git a/plugin/defer/build b/plugin/defer/build
new file mode 100755
index 0000000..8b628a2
--- /dev/null
+++ b/plugin/defer/build
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+#
+# Build an OpenVPN plugin module on *nix.  The argument should
+# be the base name of the C source file (without the .c).
+#
+
+# This directory is where we will look for openvpn-plugin.h
+INCLUDE="-I../.."
+
+CC_FLAGS="-O2 -Wall"
+
+gcc $CC_FLAGS -fPIC -c $INCLUDE $1.c && \
+gcc -fPIC -shared -Wl,-soname,$1.so -o $1.so $1.o -lc
diff --git a/plugin/defer/simple.c b/plugin/defer/simple.c
new file mode 100644
index 0000000..7311a3f
--- /dev/null
+++ b/plugin/defer/simple.c
@@ -0,0 +1,138 @@
+/*
+ *  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 test deferred authentication.  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 {
+  int dummy;
+};
+
+/*
+ * 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;
+}
+
+/* used for safe printf of possible NULL strings */
+static const char *
+np (const char *str)
+{
+  if (str)
+    return str;
+  else
+    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));
+
+  /*
+   * 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);
+
+  /* get auth_control_file filename from envp string array*/
+  const char *auth_control_file = get_env ("auth_control_file", envp);
+
+  printf ("DEFER u='%s' p='%s' acf='%s'\n",
+	  np(username),
+	  np(password),
+	  np(auth_control_file));
+
+  /* Authenticate asynchronously in 10 seconds */
+  if (auth_control_file)
+    {
+      char buf[256];
+      snprintf (buf, sizeof(buf), "( sleep 10 ; echo AUTH %s ; echo 1 >%s ) &",
+		auth_control_file,
+		auth_control_file);
+      printf ("%s\n", buf);
+      system (buf);
+      return OPENVPN_PLUGIN_FUNC_DEFERRED;
+    }
+  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);
+}
diff --git a/plugin/defer/simple.def b/plugin/defer/simple.def
new file mode 100755
index 0000000..a87507d
--- /dev/null
+++ b/plugin/defer/simple.def
@@ -0,0 +1,6 @@
+LIBRARY   OpenVPN_PLUGIN_SAMPLE
+DESCRIPTION "Sample OpenVPN plug-in module."
+EXPORTS
+   openvpn_plugin_open_v1   @1
+   openvpn_plugin_func_v1   @2
+   openvpn_plugin_close_v1  @3
diff --git a/plugin/defer/winbuild b/plugin/defer/winbuild
new file mode 100755
index 0000000..97e724a
--- /dev/null
+++ b/plugin/defer/winbuild
@@ -0,0 +1,18 @@
+#
+# Build an OpenVPN plugin module on Windows/MinGW.
+# The argument should be the base name of the C source file
+# (without the .c).
+#
+
+# This directory is where we will look for openvpn-plugin.h
+INCLUDE="-I.."
+
+CC_FLAGS="-O2 -Wall"
+
+gcc -DBUILD_DLL $CC_FLAGS $INCLUDE -c $1.c
+gcc --disable-stdcall-fixup -mdll -DBUILD_DLL -o junk.tmp -Wl,--base-file,base.tmp $1.o
+rm junk.tmp
+dlltool --dllname $1.dll --base-file base.tmp --output-exp temp.exp --input-def $1.def
+rm base.tmp
+gcc --enable-stdcall-fixup -mdll -DBUILD_DLL -o $1.dll $1.o -Wl,temp.exp
+rm temp.exp