usbsas is a free and open-source (GPLv3) tool and framework for securely reading untrusted USB mass storage devices.
Following the concept of defense in depth and the principle of least privilege, usbsas's goal is to reduce the attack surface of the USB stack. To achieve this, most of the USB-related tasks (parsing USB packets, SCSI commands, file systems, etc.) usually executed in (privileged) kernel space has been moved to user space and separated in different processes (microkernel style), each being executed in its own restricted secure computing mode.
The main purpose of this project is to be deployed as a kiosk / sheep dip station to securely transfer files from an untrusted USB device to a trusted one.
It works on GNU/Linux and is written in Rust.
Source code and additional information may be found here: https://github.com/cea-sec/usbsas