Set max character buffer len to 512 per MS specification

The MS specs determine that the character buffer lenngths
for usernames, domains, passwords, alternate shells, etc
can be up to 512 characters including the mandatory null
terminator.

common/xrdp_client_info.h

@@ -18,6 +18,8 @@
  * xrdp / xserver info / caps
  */
 
+#include "xrdp_constants.h"
+
 #if !defined(XRDP_CLIENT_INFO_H)
 #define XRDP_CLIENT_INFO_H
 
@@ -57,11 +59,11 @@ struct xrdp_client_info
   char hostname[32];
   int build;
   int keylayout;
-  char username[256];
-  char password[256];
-  char domain[256];
-  char program[256];
-  char directory[256];
+  char username[INFO_CLIENT_MAX_CB_LEN];
+  char password[INFO_CLIENT_MAX_CB_LEN];
+  char domain[INFO_CLIENT_MAX_CB_LEN];
+  char program[INFO_CLIENT_MAX_CB_LEN];
+  char directory[INFO_CLIENT_MAX_CB_LEN];
   int rdp_compression;
   int rdp_autologin;
   int crypt_level; /* 1, 2, 3 = low, medium, high */