chroot

Chroot, short for change root, is a Unix-like operating system feature that changes the root directory for the current process and its descendants. After a successful chroot, the specified directory is treated as “/,” so the process sees a restricted filesystem view that is separate from the rest of the system. The command is commonly used to create isolated testing environments, perform maintenance on a system from rescue media, or build and test software in a minimal, controlled root.

Chroot requires elevated privileges to invoke, and it does not by itself provide strong security isolation. It confines file system access but does not isolate the process’s kernel view, IPC, or networking unless combined with additional mechanisms. Consequently, a chroot jail is not a robust security boundary and can be bypassed under certain conditions or kernel exploits. For stronger isolation, modern approaches use containers with namespaces, cgroups, and seccomp, or full virtualization.

Setting up a chroot environment typically involves presenting a directory that contains a functioning root filesystem, including necessary binaries, libraries, and device nodes. Because dynamically linked executables depend on libraries, the environment must include the required shared libraries and appropriate linker. Tools such as debootstrap, buildroot, or system-package managers can assist in assembling a usable chroot tree. Once prepared, a typical invocation is: sudo chroot /path/to/newroot /bin/bash, which launches a shell inside the new root.

In summary, chroot is a useful, lightweight mechanism for filesystem isolation and testing, but it should not be relied upon for strong security boundaries.