Do You Know Where Your Code Came From? If You Don't Have Source You Aren't Secure
by on April 4, 2019
I sometimes work for Conservancy assisting in their compliance work. Conservancy follows the Principles of Community-Oriented GPL Enforcement, enforcement principles published by Conservancy and the Free Software Foundation. As the process goes, Conservancy receives complaints from users about products whose sellers aren't meeting their GPL license obligations and Conservancy may investigate. Many of these complaints are for hardware devices with embedded code. The complaints are almost always are that there is free software on the device but that the source code is not available.
Conservancy will purchase the complained-of device and independently determine whether or not there is a GPL violation, including requesting the source code. This is where the rubber meets the road, particularly for embedded devices. In phone calls with the hardware manufacturer, the manufacturer will almost always say that they don't have the code on hand and need to get it from their factory or vendor.
When I hear this, I want to gasp out loud. I'm not gasping because I find the non-compliance so surprising (it's not), but that a manufacturer is shipping a device that it has not independently confirmed was manufactured as spec'd. A manufacturer designs a device, say a home security camera, and has outsourced the manufacturing to a factory. The factory may have subcontracted with someone else for the component, who may have contracted with yet another company for the firmware. Yet despite the length and opaqueness of the supply chain, the companies we buy from are not doing any due dligence on the products they are selling. When a company tells me they don't have the source code available, I add them to the list in my head of brands I will not buy.
This is not a trivial oversight. Doorbell cameras, security cameras, televisions, baby monitors, and home audio equipment have a view into the most intimate parts of our lives, and yet the manufacturers are not doing everything they can to ensure that our private lives stay private. The component manufacturer, the firmware manufacturer, the factory, or all of them, could be adding malicious code to the device and the vendor has not taken the simplest step of verifying the software on the device does only what it is supposed to do and nothing more.
And it's an easy problem to solve. All the company needs is the source code. There is now even a free software project, Reproducible Builds, that can be used to verify that the source code provided compiles to exactly the object code found on the device.
And guess what? By performing the far more critical task of ensuring that a manufactured device has not been compromised, the source code compliance problem has been solved too.
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