rrsync(1) — Linux manual page


rrsync(1)                     User Commands                    rrsync(1)

NAME         top

       rrsync - a script to setup restricted rsync users via ssh logins

SYNOPSIS         top

       rrsync [-ro|-rw] [-munge] [-no-del] [-no-lock] DIR

       The single non-option argument specifies the restricted DIR to
       use. It can be relative to the user's home directory or an
       absolute path.

       The online version of this manpage (that includes cross-linking
       of topics) is available at

DESCRIPTION         top

       A user's ssh login can be restricted to only allow the running of
       an rsync transfer in one of two easy ways:

       o      forcing the running of the rrsync script

       o      forcing the running of an rsync daemon-over-ssh command.

       Both of these setups use a feature of ssh that allows a command
       to be forced to run instead of an interactive shell.  However, if
       the user's home shell is bash, please see BASH SECURITY ISSUE for
       a potential issue.

       To use the rrsync script, edit the user's ~/.ssh/authorized_keys
       file and add a prefix like one of the following (followed by a
       space) in front of each ssh-key line that should be restricted:

           command="rrsync DIR"
           command="rrsync -ro DIR"
           command="rrsync -munge -no-del DIR"

       Then, ensure that the rrsync script has your desired option
       restrictions. You may want to copy the script to a local bin dir
       with a unique name if you want to have multiple configurations.
       One or more rrsync options can be specified prior to the DIR if
       you want to further restrict the transfer.

       To use an rsync daemon setup, edit the user's
       ~/.ssh/authorized_keys file and add a prefix like one of the
       following (followed by a space) in front of each ssh-key line
       that should be restricted:

           command="rsync --server --daemon ."
           command="rsync --server --daemon --config=/PATH/TO/rsyncd.conf ."

       Then, ensure that the rsyncd.conf file is created with one or
       more module names with the appropriate path and option
       restrictions.  If rsync's --config option is omitted, it defaults
       to ~/rsyncd.conf.  See the rsyncd.conf(5) manpage for details of
       how to configure an rsync daemon.

       When using rrsync, there can be just one restricted dir per
       authorized key.  A daemon setup, on the other hand, allows
       multiple module names inside the config file, each one with its
       own path setting.

       The remainder of this manpage is dedicated to using the rrsync

OPTIONS         top

       -ro    Allow only reading from the DIR. Implies -no-del and -no-

       -wo    Allow only writing to the DIR.

       -munge Enable rsync's --munge-links on the server side.

              Disable rsync's --delete* and --remove* options.

              Avoid the single-run (per-user) lock check.  Useful with

       -help, -h
              Output this help message and exit.


       The rrsync script validates the path arguments it is sent to try
       to restrict them to staying within the specified DIR.

       The rrsync script rejects rsync's --copy-links option (by
       default) so that a copy cannot dereference a symlink within the
       DIR to get to a file outside the DIR.

       The rrsync script rejects rsync's --protect-args (-s) option
       because it would allow options to be sent to the server-side that
       the script cannot check.  If you want to support --protect-args,
       use a daemon-over-ssh setup.

       The rrsync script accepts just a subset of rsync's options that
       the real rsync uses when running the server command.  A few extra
       convenience options are also included to help it to interact with
       BackupPC and accept some convenient user overrides.

       The script (or a copy of it) can be manually edited if you want
       it to customize the option handling.


       If your users have bash set as their home shell, bash may try to
       be overly helpful and ensure that the user's login bashrc files
       are run prior to executing the forced command.  This can be a
       problem if the user can somehow update their home bashrc files,
       perhaps via the restricted copy, a shared home directory, or
       something similar.

       One simple way to avoid the issue is to switch the user to a
       simpler shell, such as dash.  When choosing the new home shell,
       make sure that you're not choosing bash in disguise, as it is
       unclear if it avoids the security issue.

       Another potential fix is to ensure that the user's home directory
       is not a shared mount and that they have no means of copying
       files outside of their restricted directories.  This may require
       you to force the enabling of symlink munging on the server side.

       A future version of openssh may have a change to the handling of
       forced commands that allows it to avoid using the user's home

EXAMPLES         top

       The ~/.ssh/authorized_keys file might have lines in it like this:

           command="rrsync client/logs" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAzG...
           command="rrsync -ro results" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAmk...

FILES         top


SEE ALSO         top

       rsync(1), rsyncd.conf(5)

VERSION         top

       This manpage is current for version 3.2.7 of rsync.

CREDITS         top

       rsync is distributed under the GNU General Public License.  See
       the file COPYING for details.

       An rsync web site is available at https://rsync.samba.org/ and
       its github project is https://github.com/WayneD/rsync.

AUTHOR         top

       The original rrsync perl script was written by Joe Smith.  Many
       people have later contributed to it.  The python version was
       created by Wayne Davison.

COLOPHON         top

       This page is part of the rsync (a fast, versatile, remote (and
       local) file-copying tool) project.  Information about the project
       can be found at ⟨https://rsync.samba.org/⟩.  If you have a bug
       report for this manual page, see
       ⟨https://rsync.samba.org/bugzilla.html⟩.  This page was obtained
       from the tarball fetched from
       ⟨https://download.samba.org/pub/rsync/⟩ on 2022-12-17.  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

rrsync from rsync 3.2.7        20 Oct 2022                     rrsync(1)

Pages that refer to this page: rsync(1)