phpman > man > rrsync(1)

rrsync(1)                                   User Commands                                  rrsync(1)



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

SYNOPSIS
       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
       https://download.samba.org/pub/rsync/rrsync.1.

DESCRIPTION
       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 re‐
       stricted:

           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 configura‐
       tions. 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 ap‐
       propriate 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 script.

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

       -wo    Allow only writing to the DIR.

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

       -no-del
              Disable rsync's --delete* and --remove* options.

       -no-lock
              Avoid the single-run (per-user) lock check.  Useful with -munge.

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

SECURITY RESTRICTIONS
       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 --pro‐‐
       tect-args, use a daemon-over-ssh setup.

       The rrsync script accepts just a subset of rsync's options that the real rsync uses when run‐
       ning the server command.  A few extra convenience options are also included to help it to in‐
       teract 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.

BASH SECURITY ISSUE
       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 re‐
       stricted 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 shell.

EXAMPLES
       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
       ~/.ssh/authorized_keys

SEE ALSO
       rsync(1), rsyncd.conf(5)

VERSION
       This manpage is current for version 3.2.7 of rsync.

CREDITS
       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
       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.



rrsync from rsync 3.2.7                      20 Oct 2022                                   rrsync(1)