Control access to public folder

I have been working on a little project to control the access to the public folder. So that my Admin user can read/write/delete/execute basically do whatever they want but all other users of the drive only have read/execute access to the folder.

This effects the FTP and lan \ 192.168.x.x & \ hostnamehere connections to control the access with no adverse effects that i can find so far, the software works fine to see drive all users can access their data based on how dashboard is setup. it only restricts the Public folder.

Here is what i have done to make this happen inside ssh access typed commands:

cd /shares
chmod 755 Public
chown Admin Public

this gave the admin user full access all others just read/execute
now on to my next problem any new folders added would not get the permissions applied
so i edited the crontab file to run a script with the above commands in it every 30 minutes witch is good enough for me
to have a 30 minute tolerance for permission errors. i did this with

crontab -e

and added new line of

0,30 * * * * sh /home/ > /home/crontablog.log 2>&1

this ran the chmod and chown commands on the public folder every 30 minutes and outputs a log on error.

Now on to my problem currently… every time the firmware updates on my mycloud
the crontab file gets reset and it deletes my permissions file out of /home.
the permissions stay applied but wont update any longer due to the 2 above things getting reset.

is there any way i can stop a firmware update from wiping out my crontab?
i can deal with it wiping the file as i could just write a crontab to check if file exists if not just replace it

Look into the user-start file in CacheVolume. There is a symbolic link in /etc/rc2.d to this file. It does not get altered when the software is updated. You can put what ever commands you need to be run on boot.