Google Chromebook owners who often have to work with Linux applications can attest that one of the biggest limitations of the Crostini Linux container is that it does not have direct access to the device's file system, but it seems that this could be changing soon. . The way things work now forces the files generated in the Crostini container to remain there, and prevents users from using local files within the container application. An alternative solution is available through SSH, but it can be cumbersome. A recent code confirms the Chromium repository points to Google using Crostini's built-in SSH and a pre-built action library to create an easier solution, essentially giving Crostini file access privileges to and from the Chromebook.
Taking a look at the code is confirmed, it seems that each container instance in Crostini will receive its own private key, which will be invoked when it attempts to access the Chrome OS file system. The Crostini container will also be added to a list of "known hosts". While the confirmation and its comments do not explain in detail, it is likely to mean that Chrome OS will recognize an authorized Crostini instance and allow access if the private key is removed. From there, a mount command is issued that will mount the Chrome OS file system directly into the Crostini container, which essentially allows the Linux application to access it as if it were a flash drive inserted into a Linux PC.
This approach, in general, is quite safe and could cause much less headaches compared to trying to integrate the file system of the particular instance of Crostini directly with Chrome OS. It also uses hooks and calls that are already present in both Crostini and Chrome OS, which means that once the solution is ready, Google could activate the switch at any time. In the same way, once the commitment is live, the entrepreneurial users who know how to compile Chrome OS or any of its derivatives can include this change to give Crostini the access it needs for Linux applications to interact with local files. While it could be argued that dealing with local files is less of a Crouton headache, using Crostini for the use of unique applications or tests can be much less cumbersome than setting up a full shell session and operating system in Crouton, for users who normally they work in the Chrome OS environment and use Linux applications less frequently, or do not want to deal with the complexities of introducing new file systems and hooks into an established Linux virtual machine.