more on Google NERF

Google NERF looks interesting, they keep UEFI’s PI but replace the UEFI layers with Linux kernel, and the code is written in Go. Looks like they’re focusing on removing dynamic code in UEFI and SMM. Unclear about their position towards dynamic code in ACPI, as well as PCIe (eg, PCIleech-style attacks).

The slides from the recent North American OSS presentation are online, but I can’t find the video online:

Click to access Linuxcon%202017%20NERF.pdf

There’s an upcoming European OSS event upcoming:

Replace Your Exploit-Ridden Firmware with Linux
Ronald Minnich, Google

With the WikiLeaks release of the vault7 material, the security of the UEFI (Unified Extensible Firmware Interface) firmware used in most PCs and laptops is once again a concern. UEFI is a proprietary and closed-source operating system, with a codebase almost as large as the Linux kernel, that runs when the system is powered on and continues to run after it boots the OS (hence its designation as a “Ring -2 hypervisor”). It is a great place to hide exploits since it never stops running, and these exploits are undetectable by kernels and programs. Our answer to this is NERF (Non-Extensible Reduced Firmware), an open source software system developed at Google to replace almost all of UEFI firmware with a tiny Linux kernel and initramfs. The initramfs file system contains an init and command line utilities from the u-root project (, which are written in the Go language.



U-Root: firmware solution written in Go

From 2015, something I missed because I didn’t know Go then. ;-(

U-root: A Go-based, Firmware Embeddable Root File System with On-demand Compilation
Ronald G. Minnich, Google; Andrey Mirtchovski, Cisco

U-root is an embeddable root file system intended to be placed in a FLASH device as part of the firmware image, along with a Linux kernel. The program source code is installed in the root file system contained in the firmware FLASH part and compiled on demand. All the u-root utilities, roughly corresponding to standard Unix utilities, are written in Go, a modern, type-safe language with garbage collection and language-level support for concurrency and inter-process communication. Unlike most embedded root file systems, which consist largely of binaries, U-root has only five: an init program and 4 Go compiler binaries. When a program is first run, it and any not-yet-built packages it uses are compiled to a RAM-based file system. The first invocation of a program takes a fraction of a second, as it is compiled. Packages are only compiled once, so the slowest build is always the first one, on boot, which takes about 3 seconds. Subsequent invocations are very fast, usually a millisecond or so. U-root blurs the line between script-based distros such as Perl Linux and binary-based distros such as BusyBox; it has the flexibility of Perl Linux and the performance of BusyBox. Scripts and builtins are written in Go, not a shell scripting language. U-root is a new way to package and distribute file systems for embedded systems, and the use of Go promises a dramatic improvement in their security.

Video and audio on first URL.