Added config file option "setenv FORWARD_COMPATIBLE 1" to relax

config file syntax checking to allow directives for future OpenVPN
versions to be ignored.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@3476 e7ae566f-a301-0410-adde-c780ea21d3b5

3 files changed, 33 insertions, 3 deletions

diff --git a/openvpn.8 b/openvpn.8
index 0e85983..921f8fb 100644
--- a/openvpn.8
+++ b/openvpn.8
@@ -26,7 +26,7 @@
 .\" LP paragraph
 .\" IP indented paragraph
 .\" TP hanging label
-.TH openvpn 8 "3 August 2005"
+.TH openvpn 8 "4 November 2008"
 .\"*********************************************************
 .SH NAME
 openvpn \- secure IP tunnel daemon.
@@ -2010,6 +2010,19 @@ Set a custom environmental variable
 to pass to script.
 .\"*********************************************************
 .TP
+.B --setenv FORWARD_COMPATIBLE 1
+Relax config file syntax checking so that unknown directives
+will trigger a warning but not a fatal error,
+on the assumption that a given unknown directive might be valid
+in future OpenVPN versions.
+
+This option should be used with caution, as there are good security
+reasons for having OpenVPN fail if it detects problems in a
+config file.  Having said that, there are valid reasons for wanting
+new software features to gracefully degrade when encountered by
+older software versions.
+.\"*********************************************************
+.TP
 .B --setenv-safe name value
 Set a custom environmental variable
 .B OPENVPN_name=value
diff --git a/options.c b/options.c
index 95d81a0..7187d6e 100644
--- a/options.c
+++ b/options.c
@@ -191,6 +191,8 @@ static const char usage_message[] =
   "                  flag to add a direct route to DHCP server, bypassing tunnel.\n"
   "                  Add 'bypass-dns' flag to similarly bypass tunnel for DNS.\n"
   "--setenv name value : Set a custom environmental variable to pass to script.\n"
+  "--setenv FORWARD_COMPATIBLE 1 : Relax config file syntax checking to allow\n"
+  "                  directives for future OpenVPN versions to be ignored.\n"
   "--script-security level : 0 -- strictly no calling of external programs\n"
   "                          1 -- (default) only call built-ins such as ifconfig\n"
   "                          2 -- allow calling of built-ins and scripts\n"
@@ -3267,6 +3269,12 @@ no_more_than_n_args (const int msglevel,
     return true;
 }
 
+static inline int
+msglevel_forward_compatible (struct options *options)
+{
+  return options->forward_compatible ? M_WARN : msglevel;
+}
+
 static void
 add_option (struct options *options,
 	    char *p[],
@@ -3280,6 +3288,7 @@ add_option (struct options *options,
 {
   struct gc_arena gc = gc_new ();
   const bool pull_mode = BOOL_CAST (permission_mask & OPT_P_PULL_MODE);
+  int msglevel_fc = msglevel_forward_compatible (options);
 
   ASSERT (MAX_PARMS >= 5);
   if (!file)
@@ -4377,6 +4386,11 @@ add_option (struct options *options,
   else if (streq (p[0], "setenv") && p[1])
     {
       VERIFY_PERMISSION (OPT_P_GENERAL);
+      if (streq (p[1], "FORWARD_COMPATIBLE") && p[2] && streq (p[2], "1"))
+	{
+	  options->forward_compatible = true;
+	  msglevel_fc = msglevel_forward_compatible (options);
+	}
       setenv_str (es, p[1], p[2] ? p[2] : "");
     }
   else if (streq (p[0], "setenv-safe") && p[1])
@@ -5540,9 +5554,9 @@ add_option (struct options *options,
   else
     {
       if (file)
-	msg (msglevel, "Unrecognized option or missing parameter(s) in %s:%d: %s (%s)", file, line, p[0], PACKAGE_VERSION);
+	msg (msglevel_fc, "Unrecognized option or missing parameter(s) in %s:%d: %s (%s)", file, line, p[0], PACKAGE_VERSION);
       else
-	msg (msglevel, "Unrecognized option or missing parameter(s): --%s (%s)", p[0], PACKAGE_VERSION);
+	msg (msglevel_fc, "Unrecognized option or missing parameter(s): --%s (%s)", p[0], PACKAGE_VERSION);
     }
  err:
   gc_free (&gc);
diff --git a/options.h b/options.h
index 1770bc8..c6d4e47 100644
--- a/options.h
+++ b/options.h
@@ -150,6 +150,9 @@ struct options
 # define MODE_SERVER         1
   int mode;
 
+  /* enable forward compatibility for post-2.1 features */
+  bool forward_compatible;
+
   /* persist parms */
   bool persist_config;
   int persist_mode;