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 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.

       -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 3.2.7 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.