rsync is a network protocol developed in 1996 by Andrew Tridgell and Paul Mackerras and a program for the synchronization of data, which is usually transmitted over a computer network. Synchronization of the data is unidirectional with rsync, which predestines the tool predisposed for backup and adjustment processes. Tridgell described the functionality in an article entitled “Efficient Algorithms for Sorting and Synchronization.” Because of the flexibility and speed, rsync has been deployed on multiple platforms. But especially on OpenBSD, the implementation came under criticism for safety concerns.
As the team announced, “openrsync” provides an alternative implementation of rsync that is fully tailored to the security requirements of OpenBSD. The new software was created as part of the rpki client and is under the liberal OpenBSD license. Furthermore, the implementation uses the security mechanisms of the system, which according to the developers makes them particularly robust against attacks. A disadvantage of the binding is that openrsync is quite portable, but loses one of its strengths on other systems. For example, under FreeBSD using Capsicum, the security aspects of OpenBSD’s pledge and unveil can be largely reproduced, but according to the developers, there is no adequate replacement under Linux.
The functionality of openrsync does not yet cover all the parameters of the original implementation and is limited to the most important options. According to the author, the software was tested against rsync 3.1.3 and supports protocol version 27. openrsync can now be found in the repository of the OpenBSD project.
Submitted by: Arnfried Walbrecht