NAME

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

SYNOPSIS

       rrsync [-ro|-rw] [-munge] [-no-del] [-no-lock] [-no-overwrite]  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 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 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.

       -no-overwrite
              Enforce --ignore-existing on the server. Prevents overwriting existing  files  when
              the server is the receiver.

       -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 --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.

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 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 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 3.3.0 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.