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Using Network Accounts with the Authorization file – 10.7.3

I’ve had a couple of comments about using Network based accounts / groups instead of local groups.  I’ve done some tests on 10.7.3 and here’s a couple of ways to go about it. (Thanks goes to Shane for some of the info)

My testing and examples below assume a similar setup to mine which is.  Staff are allocated one machine each.  Windows Server 2008 Active Directory setup, Domain Users and Mac’s bound to AD via the native apple plug-in.  A local admin account on every mac for installing software, ARD use, backup for when directory services falls over.  Try and adjust my examples below to fit your needs.

A. Create a new local group and add users to it. (Small scale scenarios)

1. Login as an admin account, goto System Preferences > User & Groups, unlock the pane and click the + button.

2. Scroll down and choose the Group option at the bottom and give it a name.  i.e. testgroup.

3. Simply tick the users you want in that group and close the pane.  In the picture below I’ve added an account called Mickey Mouse.  The machine was bound to Active Directory via the built in Apple plugin then I logged in as the network user (mimouse) and forced a local home, creating a “Managed, Mobile” account.  I’ve also ticked my local admin account called The Boss.

4. You now have a group with your network non-admin account and your local admin account. As pictured below.

Now you can do as per my previous post simply replacing lpadmin with testgroup / whatever you called your new group for whichever Preference Panes you want to unlock.

B. Create a new local group and add existing groups to it, nested groups. (Larger scale scenario)

The example above works for a machine that has one or two known users but not multiple unknown users logging in. We’re going to add existing groups where the members are calculated, to a new local group so it covers all potential users.  Where going to effectively add Domain Users and local admins to this new group.

1. Create a new local group for the purpose.  As per above via Users & Groups or via the command line. (have a look at dscl . -create)

2. Active Directory users get added to the netaccounts local group when you login on your Mac.  Both Mobile and Network accounts. (See my note at the bottom about directly using Domain Groups)  To verify, login as a non-admin AD based user and check the account is in that group via Terminal:  dsmemberutil checkmembership -U mimouse -G netaccounts  (subbing mimouse for your network accounts shortname) you can also use dseditgroup -o checkmember netaccounts (it will check if the current terminal sessions user is in the group or not)

you’ll get a one line reply like this:  “yes mimouse is a member of netaccounts”

3. Add the netaccounts group to your new group, in my example  it’s called testgroup.  In Terminal paste the following: sudo dseditgroup -o edit -a netaccounts -t group testgroup

4. Verify your AD user is now also now part of test group. dsmemberutil checkmembership -U mimouse -G testgroup

 Note: Any other non-admin domain users that login to this machine will also get put into the netaccounts group and therefore be part of your new ‘testgroup’ automatically.

5. Add the local administrator group to this group as well.   You want to be able to edit all the System Preferences as well.  In Terminal paste the following: sudo dseditgroup -o edit -a admin -t group testgroup

6. Verify it’s worked as per step 4, subbing in a local admin’s username.  In my example ‘theboss’.

7. You now have a local group called testgroup, which contains nested groups Administrators and Network Accounts.  Open System Preferences > Users & Groups and you should see a result as pictured below.  Noting that you can’t achieve this result from the GUI.

Accounts Pane

Now you can do as per my previous post simply replacing lpadmin with testgroup / whatever you called your new group for whichever Preference Panes you want to unlock.

NOTE: You can also directly add Domain Groups into this new local group: i.e. below I’ve added Domain Admins and Domain Users from Active Directory to my group.

sudo dseditgroup -o edit -a “Domain Users” -t group testgroup
sudo dseditgroup -o edit -a “Domain Admins” -t group testgroup

BUT this membership is calculated or searched for at the time of credential checking.  A simple check of Shutting down, booting up with no network cable plugged in, logging in as my mobile AD account yields no mimouse is NOT a member of testgroup.  If I connect the Ethernet cable and wait 60 seconds it returns yes they are.  This gets cached for some time period.  I wouldn’t recommending doing it this way, as a network connection is basically required at all times.

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Making use of the /etc/authorization file in Lion / 10.7.x

This post will look at putting the authorization file to use in a partially managed Mac environment.  Yes some of this can be done via OD & MCX but as we’re a small environment we don’t use it nor really need it.  All testing was done with 10.7.2 and I’ve been using it with all our Mac’s up to 10.8.2 at the moment.

Q:  What’s the problem we want to solve?
A
: I want my users to be somewhere in between what Apple defines as a “Standard User” and a “Admin User”.  Stealing from Windows terminology,  I want them to be a “Power User”.

I want the System Preference panes marked below with red X’s to no longer require an Admin password to unlock them.  Your environment will be different to mine, so pick, choose & extend these ideas to what fits your environment.

Desired Sys Prefs

Energy Saver:  I want users to be able to set their own Sleep schedules.  I don’t want support requests from users about changing their sleep from 10 to 15minutes. Cons:   The potential downside of this is that I really don’t want them to be able to turn off  “Wake for Ethernet network access” (ARD use) but I’m hoping most won’t mess with this setting.

Print & Scan: I want laptop users to be able to add a home inkjet / laser printer. Cons:  I don’t really want them deleting or adding other printers at work so I’m not actually going to unlock this preference pane in this example.  But you may want to in your environment.  I will do it by adding the user to the lpadmin group instead.  Adding a user to the lpadmin group allows them to install or remove printers it doesn’t however unlock the Print & Scan System Preference pane but it does allow them to use the less obvious + and – buttons in that pane to make changes.  They can also use the File > Print > Printer > Add New Printer… option to add a home printer.

Network: I want laptop users to be able to adjust network settings as they travel.  Often at conferences, home or other sites, custom network settings or proxy settings are required.  Opening this up lets them adjust them as needed. Cons: Users can break their network settings which may yield a support request.

Date & Time: I want laptop users to be able to change the time zone if the ‘automatic’ feature fails.  Also if the PRAM battery fails I want users to be able to set the correct date and time. Cons:  Users can be on the wrong time zone / time which will effect things like AD based login’s.

Time Machine: I want laptop users to be able to setup a USB drive or Time Capsule at home as they’re backup device.

Not mentioned above: Software Update:  I plan to enable Software Update once I get my own Software Update Server running using Reposado.  This way I can enable standard users to update their own Mac’s via the built-in Apple system but control what updates are available via reposado.  You can also do this via Munki or this app at http://www.littleboyblue.co.nz/ instead.

In my environment I’ve decided for now that I only want to open the above extra Preference Panes up for laptop users.  Desktop users I can help over the phone easily, change things remotely via ARD or go visit them.  Laptop users who are overseas or not on-site are the main concern as I can’t help them easily nor allowed to give them admin credentials.

In my environment for 10.7.x we are currently using the Apple Active Directory plug-in and Mobile User Accounts with local homes.  We add laptop users to the lpadmin group so they can install printers at home.  I do this via Apple Remote Desktop (ARD) using the Send Unix Command option:  dseditgroup -o edit -a USERNAME -t user _lpadmin if doing it locally via the command line as an admin use sudo dseditgroup -o edit -a USERNAME -t user _lpadmin  To verify the user has been added use dscl . -read /Groups/lpadmin at the command line.  Looking at the “Group Membership” field.

I am going to leverage this as it distinguishes between desktop and laptop users in our environment to achieve the outcome above. You could also create a new group and use that or use another built-in group.  Be aware that creating your own group means that you’d also need to add admin accounts to that group or the admin group itself.  By default all local admin accounts are members of the lpadmin group.  You could also use the staff or everyone group to open it wider.

So from the info in my earlier post we’re going to change the following keys in the /etc/authorization file from group admin to lpadmin using TextWrangler:

<key>system.preferences</key>
<key>system.preferences.energysaver</key>
<key>system.preferences.network</key>
<key>system.preferences.datetime</key>
<key>system.preferences.timemachine</key>

changing the bottom part of each entry above from
<key>group</key>
<string>admin</string>

to

<key>group</key>
<string>lpadmin</string>

Note: TextWrangler will change the files owner and group, you can easily set it back via chown & chmod or just run Disk Utility – Repair Permissions which will set it back to root and wheel.

To make this even easier and ARD compatible I’ve adjusted a script from here which can be sent out via ARD to a Machine to change it immediately.  If a future apple update changes the file back to it’s original state it’s easily changed back.

#!/bin/bash
#Copy the authorization file to a temporary location & make it a plist
/bin/cp -pr /etc/authorization /private/tmp/authorization.plist
# Unlock System Preferences for lpadmin group members.
/usr/libexec/PlistBuddy -c ‘Set :rights:system.preferences:group lpadmin’ /private/tmp/authorization.plist
# Unlock the Network Settings preference pane
/usr/libexec/PlistBuddy -c ‘Set :rights:system.preferences.network:group lpadmin’ /private/tmp/authorization.plist
# Unlock the Time Machine preference pane
/usr/libexec/PlistBuddy -c ‘Set :rights:system.preferences.timemachine:group lpadmin’ /private/tmp/authorization.plist
# Unlock the Energy saver preference pane
/usr/libexec/PlistBuddy -c ‘Set :rights:system.preferences.energysaver:group lpadmin’ /private/tmp/authorization.plist
# Unlock the Date and Time preference pane
/usr/libexec/PlistBuddy -c ‘Set :rights:system.preferences.datetime:group lpadmin’ /private/tmp/authorization.plist
# Move file back to original location
/bin/mv /private/tmp/authorization.plist /etc/authorization

You can just copy and paste the text above into the “Send Unix Command” text area in ARD and send it as a local admin or root.  Alternatively copy the text into TextWrangler, do a save as i.e. auth-changescript.sh then go to the command line and make it executable via chmod +x auth-changescript.sh then run it with sudo ./auth-changescript.sh or sudo sh auth-changescript.sh

This is what you’ll see when trying to unlock a pane as a standard user that you haven’t added to the lpadmin group.
Print Admin Prompt

And this is what you’ll see once you’ve added a standard user to the lpadmin group (or when logged in as an admin)

There’s other ways to achieve the same result.  You can change the key’s above from class “user” to “rule” keys and make your own rule at the bottom of the authorization file or use a built-in one but it’s much more complex & not well documented by Apple.