File Upload Module

Hi, I have a website running on Drupal 7.32 on a linux environment, I have a issue with my website. In my file system I have mentioned tmp folder which is in my root directory to be the temp folder.  In one of the section on my website I need to upload certain files for end users to download. Files does not get uploaded in Drupal unless I give full 777 access to tmp folder. I tried giving only write access to tmp folder, but still the file does not get uploaded. It necessarily requires execute permission for files to be uploaded. 
I do not want to give full access to tmp because there are unnecessary files getting executed through tmp folder. How do I achieve this . Any help will be greatly appreciated. 

It gives an error  

  • The file xxxx.docx could not be saved. An unknown error has occurred.
  • The file in the Upload Document field was unable to be uploaded.
Drupal version: