Revamped the script-security warning logging (version 2)

The main task of this patch is to avoid reporting the SCRIPT_SECURITY_WARNING
over and over again, in addition to not show this warning when it should not
be a problem.  This general warning should now only appear once, and only when
--script-security is not set, 0 or 1.  In all other cases this warning should
not appear.

In addition, this warning will come close to the script-hook which most probably
will fail.  It will also give a little bit more concrete hint on which script-hook
which failed.  If --script-security is 2 or 3, only the execve failure itself will
be shown.  This message will on the other hand be shown repeatedly.

This is a new rewritten version which simplifies the implementaion of the new
openvpn_run_script() function.  It was considered to remove it completely, but
due to code clearity and easy of use it was decided to make this function a static
inline function instead.  Anyhow, this function will enforce openvpn_execve_check()
to be called with the S_SCRIPT flag.

Patch ACKed on the developers meeting 2009-04-29.

Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>
Acked-by: James Yonan <james@openvpn.net>

common.h

@@ -97,6 +97,6 @@ typedef unsigned long ptr_type;
 /*
  * Script security warning
  */
-#define SCRIPT_SECURITY_WARNING "openvpn_execve: external program may not be called unless '--script-security 2' or higher is enabled.  Use '--script-security 3 system' for backward compatibility with 2.1_rc8 and earlier.  See --help text or man page for detailed info."
+#define SCRIPT_SECURITY_WARNING "WARNING: External program may not be called unless '--script-security 2' or higher is enabled.  Use '--script-security 3 system' for backward compatibility with 2.1_rc8 and earlier.  See --help text or man page for detailed info."
 
 #endif

init.c

@@ -1191,7 +1191,7 @@ do_route (const struct options *options,
       struct argv argv = argv_new ();
       setenv_str (es, "script_type", "route-up");
       argv_printf (&argv, "%sc", options->route_script);
-      openvpn_execve_check (&argv, es, S_SCRIPT, "Route script failed");
+      openvpn_run_script (&argv, es, 0, "--route-up");
       argv_reset (&argv);
     }
 

misc.c

@@ -229,7 +229,7 @@ run_up_down (const char *command,
 		  ifconfig_local, ifconfig_remote,
 		  context);
       argv_msg (M_INFO, &argv);
-      openvpn_execve_check (&argv, es, S_SCRIPT|S_FATAL, "script failed");
+      openvpn_run_script (&argv, es, S_FATAL, "--up/--down");
       argv_reset (&argv);
     }
 
@@ -492,6 +492,7 @@ openvpn_execve_allowed (const unsigned int flags)
     return script_security >= SSEC_BUILT_IN;
 }
 
+
 #ifndef WIN32
 /*
  * Run execve() inside a fork().  Designed to replicate the semantics of system() but
@@ -503,6 +504,7 @@ openvpn_execve (const struct argv *a, const struct env_set *es, const unsigned i
 {
   struct gc_arena gc = gc_new ();
   int ret = -1;
+  static bool warn_shown = false;
 
   if (a && a->argv[0])
     {
@@ -539,9 +541,10 @@ openvpn_execve (const struct argv *a, const struct env_set *es, const unsigned i
 	      ASSERT (0);
 	    }
 	}
-      else
+      else if (!warn_shown && (script_security < SSEC_SCRIPTS))
 	{
 	  msg (M_WARN, SCRIPT_SECURITY_WARNING);
+          warn_shown = true;
 	}
 #else
       msg (M_WARN, "openvpn_execve: execve function not available");

misc.h

@@ -136,6 +136,15 @@ bool openvpn_execve_check (const struct argv *a, const struct env_set *es, const
 bool openvpn_execve_allowed (const unsigned int flags);
 int openvpn_system (const char *command, const struct env_set *es, unsigned int flags);
 
+static inline bool
+openvpn_run_script (const struct argv *a, const struct env_set *es, const unsigned int flags, const char *hook)
+{
+  char msg[256];
+
+  openvpn_snprintf(msg, sizeof(msg), "WARNING: Failed running command (%s)", hook);
+  return openvpn_execve_check(a, es, flags | S_SCRIPT, msg);
+};
+
 #ifdef HAVE_STRERROR
 /* a thread-safe version of strerror */
 const char* strerror_ts (int errnum, struct gc_arena *gc);
@@ -308,6 +317,7 @@ void get_user_pass_auto_userid (struct user_pass *up, const char *tag);
 extern const char *iproute_path;
 #endif
 
+/* Script security */
 #define SSEC_NONE      0 /* strictly no calling of external programs */
 #define SSEC_BUILT_IN  1 /* only call built-in programs such as ifconfig, route, netsh, etc.*/
 #define SSEC_SCRIPTS   2 /* allow calling of built-in programs and user-defined scripts */

multi.c

@@ -109,7 +109,7 @@ learn_address_script (const struct multi_context *m,
 		   mroute_addr_print (addr, &gc));
       if (mi)
 	argv_printf_cat (&argv, "%s", tls_common_name (mi->context.c2.tls_multi, false));
-      if (!openvpn_execve_check (&argv, es, S_SCRIPT, "WARNING: learn-address command failed"))
+      if (!openvpn_run_script (&argv, es, 0, "--learn-address"))
 	ret = false;
       argv_reset (&argv);
     }
@@ -480,7 +480,7 @@ multi_client_disconnect_script (struct multi_context *m,
 	  struct argv argv = argv_new ();
 	  setenv_str (mi->context.c2.es, "script_type", "client-disconnect");
 	  argv_printf (&argv, "%sc", mi->context.options.client_disconnect_script);
-	  openvpn_execve_check (&argv, mi->context.c2.es, S_SCRIPT, "client-disconnect command failed");
+	  openvpn_run_script (&argv, mi->context.c2.es, 0, "--client-disconnect");
 	  argv_reset (&argv);
 	}
 #ifdef MANAGEMENT_DEF_AUTH
@@ -1594,7 +1594,7 @@ multi_connection_established (struct multi_context *m, struct multi_instance *mi
 		       mi->context.options.client_connect_script,
 		       dc_file);
 
-	  if (openvpn_execve_check (&argv, mi->context.c2.es, S_SCRIPT, "client-connect command failed"))
+	  if (openvpn_run_script (&argv, mi->context.c2.es, 0, "--client-connect"))
 	    {
 	      multi_client_connect_post (m, mi, dc_file, option_permissions_mask, &option_types_found);
 	      ++cc_succeeded_count;

socket.c

@@ -1695,7 +1695,7 @@ link_socket_connection_initiated (const struct buffer *buf,
       struct argv argv = argv_new ();
       setenv_str (es, "script_type", "ipchange");
       ipchange_fmt (true, &argv, info, &gc);
-      openvpn_execve_check (&argv, es, S_SCRIPT, "ip-change command failed");
+      openvpn_run_script (&argv, es, 0, "--ipchange");
       argv_reset (&argv);
     }
 

ssl.c

@@ -983,7 +983,7 @@ verify_callback (int preverify_ok, X509_STORE_CTX * ctx)
 		   ctx->error_depth,
 		   subject);
       argv_msg_prefix (D_TLS_DEBUG, &argv, "TLS: executing verify command");
-      ret = openvpn_execve (&argv, opt->es, S_SCRIPT);
+      ret = openvpn_run_script (&argv, opt->es, 0, "--tls-verify script");
 
       if (opt->verify_export_cert)
         {
@@ -3344,7 +3344,7 @@ verify_user_pass_script (struct tls_session *session, const struct user_pass *up
       argv_printf (&argv, "%sc %s", session->opt->auth_user_pass_verify_script, tmp_file);
       
       /* call command */
-      retval = openvpn_execve (&argv, session->opt->es, S_SCRIPT);
+      retval = openvpn_run_script (&argv, session->opt->es, 0, "--auth-user-pass-verify");
 
       /* test return status of command */
       if (system_ok (retval))

win32.c

@@ -952,6 +952,8 @@ int
 openvpn_execve (const struct argv *a, const struct env_set *es, const unsigned int flags)
 {
   int ret = -1;
+  static bool exec_warn = false;
+
   if (a && a->argv[0])
     {
       if (openvpn_execve_allowed (flags))
@@ -1002,9 +1004,10 @@ openvpn_execve (const struct argv *a, const struct env_set *es, const unsigned i
 	      ASSERT (0);
 	    }
 	}
-      else
+      else if (!exec_warn && (script_security < SSEC_SCRIPTS))
 	{
 	  msg (M_WARN, SCRIPT_SECURITY_WARNING);
+          exec_warn = true;
 	}
     }
   else