(In)Security in Home Embedded Devices Jim Gettys says software needs to be maintained for decades considering where it is being deployed (e.g., embedded in products with multi-decade lifetimes, such as buildings) and the criticality of some of that software, an unpredictable attribute — a product might become unplanned “infrastructure” for example if it is widely deployed and other things come to depend on it. Without maintenance, including deployment of updates in the field, software (and thus systems it is embedded in) becomes increasingly insecure as vulnerabilities are discovered (cites a honeymoon period enjoyed by new systems).
This need for long-term maintenance and field deployment implies open source software and devices that users can upgrade — maintenance needs to continue beyond the expected life of any product or organization. “Upgrade” can also mean “replace” — perhaps some kinds of products should be more modular and with open designs so that parts that are themselves embedded systems can be swapped out. (Gettys didn’t mention, but replacement can be total. Perhaps “planned obsolescence” and “throwaway culture” have some security benefits. I suspect the response would be that many things continue to be used for a long time after they were planned to be obsolete and most of their production run siblings are discarded.)
But these practices are currently rare. Product developers do not demand source from chip and other hardware vendors and thus ship products with “binary blob” hardware drivers for Linux kernel which cannot be maintained, often based on kernel years out of date when product is shipped. Linux kernel near-monoculture for many embedded systems, increasing security threat. Many problems which do not depend on hardware vendor cooperation, ranging from unintentionally or lazily not providing source needed for rest of system, to intentionally shipping proprietary software, to intentionally locking down device to prevent user updates. Product customers do not demand long-term secure devices from product developers. There is little effort to fund commons-oriented embedded development (in contrast with Linux kernel and other systems development for servers, which many big companies fund).
Gettys is focused on embedded software in network devices (e.g., routers) as network access is critical infrastructure much else depends on, including the problem at hand: without network access, many other systems cannot be feasibly updated. He’s working on CeroWrt a cutting edge version of OpenWrt firmware, either of which is several years ahead of what typically ships on routers. A meme Gettys wishes to spread, the earliest instance of which I could find is on cerowrt-devel, a harsh example coming the next week:
Friends don’t let friends run factory firmware.
Cute. This reminds me of something a friend said in a group discussion that touched on security and embedded in body (or perhaps it was mind embedded in) systems, along the lines of “I wouldn’t run (on) an insecure system.” Or malware would give you a bad trip.
But I’m ambivalent. Most people, thus most friends, don’t know what factory firmware is. Systems need to be much more secure (for the long term, including all that implies) as shipped. Elite friend advice could help drive demand for better systems, but I doubt “just say no” will help much — its track records for altering mass outcomes, e.g., with respect to proprietary software or formats, seems very poor.
In Q&A someone asked about centralized cloud silos. Gettys doesn’t like them, but said without long-term secure alternatives that can be deployed and maintained by everyone there isn’t much hope. I agree.
You may recognize open source software and devices that users can upgrade above as roughly the conditions of GPL-3.0. Gettys mentioned this and noted:
- It isn’t clear that copyright-based conditions are effective mechanism for enforcing these conditions. (One reason I say copyleft is a prototype for more appropriate regulation.)
- Of “life, liberty, and pursuit of happiness”, free software has emphasized the latter two, but nobody realized how important free software would be for living one’s life given the extent to which one interacts with and depends on (often embedded) software. In my experience people have realized this for many years, but it should indeed move to the fore.
Near the end Gettys asked what role industry and government should have in moving toward safer systems (and skip the “home” qualifier in the talk title; these considerations are at least as important for institutions and large-scale infrastructure). One answer might be in open policy. Public, publicly-interested, and otherwise coordinated funders and purchasers need to be convinced there is a problem and that it makes sense for them to demand their resources help shift the market. The Free Software Foundation’s Respects Your Freedom criteria (ignoring the “public relations” item) is a good start on what should be demanded for embedded systems.
Obviously there’s a role for developers too. Gettys asked how to get beyond the near Linux kernel monoculture, mentioning BSD. My ignorant wish is that developers wanting to break the monoculture instead try to build systems using better tools, at least better languages (not that any system will reduce the need for security in depth).
Here’s to a universal, secure, and resilient web and technium. Yes, these features cost. But I’m increasingly convinced that humans underinvest in security (not only computer, and at every level), especially in making sure investments aren’t theater or worse.
