FreeBSD Jails Containers
Since system administration is a difficult task, many tools have been developed to make life easier for the administrator. These tools often enhance the way systems are installed, configured, and maintained. One of the tools which can be used to enhance the security of a FreeBSD system is jails. Jails have been available since FreeBSD 4.X and continue to be enhanced in their usefulness, performance, reliability, and security.
Jails build upon the chroot(2) concept, which is used to change the root directory of a set of processes. This creates a safe environment, separate from the rest of the system. Processes created in the chrooted environment can not access files or resources outside of it. For that reason, compromising a service running in a chrooted environment should not allow the attacker to compromise the entire system.
However, a chroot has several limitations. It is suited to easy tasks which do not require much flexibility or complex, advanced features. Over time, many ways have been found to escape from a chrooted environment, making it a less than ideal solution for securing services.
Jails improve on the concept of the traditional chroot environment in several ways.
In a traditional chroot environment, processes are only limited in the part of the file system they can access. The rest of the system resources, system users, running processes, and the networking subsystem are shared by the chrooted processes and the processes of the host system. Jails expand this model by virtualizing access to the file system, the set of users, and the networking subsystem. More fine-grained controls are available for tuning the access of a jailed environment. Jails can be considered as a type of operating system-level virtualization.
FreeBSD: https://www.freebsd.org
Doc Jails: https://docs.freebsd.org/en/books/han...
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