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13Sep/110

Smartcards, certificates & OS X: Does Lion Roar or Meow?

I spent some time the week before last dealing with smartcards, certificates, Macs and OS X Lion (10.7), specifically. My initial take on Lion was this; I can't believe Apple has taken this direction for the enterprise user.

Before going any further, I should come clean and say I love Apple products. As a consumer, they do what I need, and work as expected. The fact that I've not had to rebuild my wife's MacBook in it's entire life (of more than 3 years) is remarkable. That all changed with OS X Lion. I downloaded it, and was not impressed from the get go. Just starting with the fact that I had to hunt down the DMG file so I would have a copy was irritating, and things continued from there. But I work with technology, need to keep up, and wanted to check out the buzz.

I also did some initial research, but articles like this one didn't help; http://www.macworld.com/article/161493/2011/08/lion_enterprise.html . This guy clearly doesn't run an "enterprise shop" and probably considers an office of 10-15 people to be representative of an enterprise. But I bit the bullet, upgraded my personal MacBook Pro, and have been wincing since. But that was as an end-user. On the enterprise side, things turned out to be worse. The AD Plug-in - broken. The Login Screen - completely screwed up. Apple broke everything when it came to Directory Services and the Login page. And to top it all off, smart card support has been deprecated! Really? This is enterprise ready?

Before we go any further, here's a quick review of how smart cards worked in OS X prior to 10.7:

  1. A card is inserted into the reader
  2. The reader uses the tokend file (ships with the OS) as a driver to read the certificate off the card
  3. The login screen is re-drawn, the username is pulled off the card (to display on the screen), and the screen is changed to only display the PIN request field
  4. The user enters the PIN tied to the card
  5. The certificate (issued by a Certificate Authority aka CA) is confirmed to be valid
  6. The CA's certificate is also checked, and confirmed to be valid, so it's certificate (and any up the chain) have to be in the OS X Keychain
  7. The user is allowed to log in

Apple no longer ships tokend files (step #2), and the default login window is no longer refreshed by a smartcard insert (though it does still flicker). We have since had a very helpful conversation with an Apple architect, and will be making changes to make it all work properly in Lion, but in the mean time, it's possible to get it all working with some elbow grease and lowered expectations.

So . . . how did we do it? Well, we started with the QAS Smartcard guide that you can find with the standard QAS documentation. And there's a whole lot of good stuff there about smartcards and certs, but here's what I boiled it down to:

1. Go to http://smartcardservices.macosforge.org/ and download the latest package to get the tokend needed to read the specific cards you are using. Apple has open sourced it all, and are relying on non-Apple folks to maintain this. If your card is not there, you will need to ask your smartcard vendor to give you a tokend file (basically, a little library to allow you to work against the specific card). We were lucky enough to be using CACs so the tokend we needed was in the beta2 batch from Aug 19, 2011.

2. Once the tokend is installed, and in place (and QAS is already up and running), run the following commands in Terminal to set up QAS to be able to use the smartcard:

sudo /opt/quest/bin/vastool smartcard configure \
pkcs11 lib /usr/libexec/SmartCardServices/pkcs11/tokendPKCS11.so

# just a test with a valid smartcard to make sure it works
sudo /opt/quest/bin/vastool smartcard test \
library /usr/libexec/SmartCardServices/pkcs11/tokendPKCS11.so

sudo /opt/quest/bin/vastool smartcard configure macos

(note that tokendPKCS11.so is the name of the file we used - your mileage may vary)

3. The client I was working with had 3 CAs in their certificate chain, so all 3 CAs had to be imported into Keychain. What that means is that Keychain had to have a copy of every CA cert that is in the chain of the user. We actually used a Windows host, and got those certificates in a cer format (crt would work as well) and used the QAS Files policy to get them over to the /etc/opt/quest/vas/ folder. We then imported them onto the Mac using the following commands:

sudo /usr/bin/security add-trusted-cert -k \
/Library/Keychains/System.keychain -r trustRoot -d /etc/opt/quest/vas/enterpriseCA.crt

sudo /usr/bin/security add-trusted-cert -k \
/Library/Keychains/System.keychain -r trustRoot -d /etc/opt/quest/vas/layer1.crt

sudo /usr/bin/security add-trusted-cert -k \
/Library/Keychains/System.keychain -r trustRoot -d /etc/opt/quest/vas/layer2.crt

We put these 3 commands into a script that deployed as a GPO Script policy that ships with QAS and set to 'run once' after the machine is joined.

After that, we were able to log in, but not without some trial and error. It turns out that if we had our card in the reader, and everything configured before the login window was drawn, we had the correct username read off the card, and a single field (labelled 'Password') that allowed us to enter a PIN and login. If we inserted the card after the login screen was already drawn with 2 fields (labelled 'Username' and 'Password'), we could not use the smart card to login, but could get in with the AD credentials, or a set of local credentials.

That was it. Most of it was what you'll find in the install guide, along with some additional configuration and troubleshooting sections. Also, don't think that smartcards can be bypassed with QAS. In the testing that we did, we left it open to allow username/password and local accounts to log in. But we didn't have to. QAS allows you to configure an entire host to require smart cards for login by editing vas.conf. Add the following directive:

require-smartcard = true

under the [vas_macos] section. You can set this option for multiple machines using group policy QAS Configuration policy extension. In addition, you can enforce this on a user-by-user basis by setting the 'SmartCard Required For Interactive Login' option on each user using Active Directory Users and Computers (ADUC).

(edited 2011-09-13 21:42 GMT to correct some formatting problems)

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Copyright (C) 2010-2011 Dmitry Kagansky – All opinions expressed are those of the respective author and do not reflect the views of any affiliate, partner, employer or associate.