This article is from the Frequently Asked Questions for Linux, the Free/Open Source UNIX-like operating system kernel that runs on many modern computer systems. Maintained by David C. Merrill with numerous contributions by others. (v1.0).
A: Recent kernels can mount (read only) the UFS file system used by System V; Coherent; Xenix; BSD; and derivatives like SunOS, FreeBSD, NetBSD, and NeXTStep. UFS support is available as a kernel compile-time option and a module.
See How To Upgrade/Recompile a Kernel.