Smart-card logon for OS X (part I)


OS X in the enterprise

Apple is not exactly known for an enthusiastic enterprise scenarios, which is surprising considering the company’s steady rise in popularity as standard issue IT equipment at large companies. It was common for Mac-operations team at Google to frequently report bugs that made it difficult to manage the enterprise fleet— and Google has thousands of Macbooks company wide. These were routinely ignored and under-prioritized by a culture more focused on designing shiny objects than pedestrian tasks like enterprise controls. So one would expect that a decidedly enterprise-oriented security feature along the lines of smart-card logon could not possibly work on OS X. But the real surprise is it can be made to work using only open source software and in spite of Apple’s best attempts to deprecate all things smart-card related.

Market pressure: it works

Back-tracking  we have the first riddle: why did a consumer-oriented platform known more for flashy graphics than high-security scenarios even bother implementing smart-card support in the first place? The credit for that goes to the US government—indirectly. Presidential directive HSPD-12 called for a common identification standard for federal employees and contractors. In response, NIST developed FIPS 201 as a comprehensive standard encompassing hardware/software for employee badges, PKI-based credentials on those badges and framework for identity management built around those credentials. The vision was ambitious, encompassing both physical access- say getting into restricted areas inside an airport- and logical access such as authenticating to a server in the cloud. Lynchpin of this vision was the CAC (Common Access Card), later replaced by PIV or Personal Identity Verification card. Compliance with CAC and PIV became baseline requirement for certain product sales to the federal government.

That same demand got Windows Vista playing well with CAC and PIV. (Not that it mattered, as Vista never succeeded in the marketplace.) Much better out-of-the-box support carried over into Windows 7. Apple was not immune to that pressure either. OS X had its own proprietary tokend stack for interacting with smart-cards, comparable to the Windows smart-card mini driver architecture. A tokend module for PIV was provide starting with 10.5 to enable standard PIV scenarios such as email encryption or authenticating to websites in a browser.

Deprecated in favor of?

“There are 2 ways to do anything at Google: the deprecated one and the one that does not yet work.” — inside joke at Google

This is where the paths between Apple and MSFT diverged. MSFT continued to invest in improving the smart-card stack, introducing new mini-driver models and better PIV integration. OS X Lion removed support for tokend, no longer shipping the modules in the core OS image. This was the culminating act of Apple washing its hands clean off this pesky security technology, which had started earlier by open-sourcing the smart-card services component earlier and handing off development to a group of volunteers clustered around an open-source project.

In principle punting all development work to an open-source community does not sound too bad. Building blocks are freely available, if anyone cares to compile from sources and install the components manually. In practice most companies do not want to deal with the complexity of maintaining their own packages or watching updates from the upstream open-source project. Third-party vendors [this, that, others] stepped into the void to provide complete solutions going beyond tokend modules, offering additional utilities for administering the card that missing from OS X.

Apple may eventually define a new cryptography architecture with feature parity to CDSA. At the moment nothing ships in the box for enabling smart-card support, not even for PIV. But relics of the supposedly deprecated architecture still survive even in Mavericks. That foundation combined with tokend modules shipping in OpenSC installer- derived from that original open-source release- allow implementing smart-card logon using only free software.

[continued]

CP

One thought on “Smart-card logon for OS X (part I)

  1. While reading work email using my Smart Card, OS X (Sierra) detected the Smart Card and automatically initiated the process to utilize the card for authentication. I only use it for reading work email and remote logon to work. Have you posted the instructions (or can you) for returning OS X back to login/password authentication? THANK YOU!!

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