Fixed a bug where hashcat did not check the return of realpath() and crashes uncontrolled if the path does not exist

This fixes https://github.com/hashcat/hashcat/issues/399

docs/changes.txt

@@ -11,6 +11,7 @@
 ##
 
 - Fixed a bug where hashcat is suppressing --machine-readable output in the final status update
+- Fixed a bug where hashcat did not check the return of realpath() and crashes uncontrolled if the path does not exist
 
 * changes v2.01 -> v3.00:
 

src/hashcat.c

@@ -6139,6 +6139,20 @@ int main (int argc, char **argv)
   char *resolved_install_folder = realpath (INSTALL_FOLDER, NULL);
   char *resolved_exec_path      = realpath (exec_path, NULL);
 
+  if (resolved_install_folder == NULL)
+  {
+    log_error ("ERROR: %s: %s", resolved_install_folder, strerror (errno));
+
+    return (-1);
+  }
+
+  if (resolved_exec_path == NULL)
+  {
+    log_error ("ERROR: %s: %s", resolved_exec_path, strerror (errno));
+
+    return (-1);
+  }
+
   char *install_dir = get_install_dir (resolved_exec_path);
   char *profile_dir = NULL;
   char *session_dir = NULL;