rsync - Aug 2009 - Using rsync to backup remote server as root

Hi there,
  I use this rsync command to backup "/" of a remote server:

rsync -Hav --delete --exclude-from=backup.excludes --delete-excluded -e
"ssh -p
45658" root at samwise:/ /mnt/backup/samwise/backup

Where:

samwise: is the name of the server (yes yes, I know, naming computer after
Hobbits may be considered bad form)

45685 is the port samwise is listening on for ssh.

I need the user to be root so they can see all files on the remote server.
The problem is that to do this I have to turn on the "PermitRootLogin"
setting in the sshd configuration on the remote server as well as
add "root" to the "AllowUsers" setting. For security reasons
I don't want
to have to do that.

How do I enable a full backup of the remote server without allowing root top
log in to ssh? Can I somehow get rsync to login as a normal user and then
do some kind of "sudo" command?

Thanks.

On 27/08/2009, at 4:18 PM, Allistar wrote:
> How do I enable a full backup of the remote server without allowing  
> root top
> log in to ssh? Can I somehow get rsync to login as a normal user and  
> then
> do some kind of "sudo" command?

--rsync-path="sudo rsync"

--
Nathan Ward

> > --rsync-path="sudo rsync"
>
> Another way to achieve something similar would be to have PermitRoot  
> set
> to without-password, and then set up a key pair for remote login.  In
> authorized_keys2, the remote access for this key pair can be limited  
> to
> the rsync command.
>
> When considering these, be sure to look at your security goals and how
> they're impacted.  In the sudo case, you're giving a user account
the
> ability to run rsync as root.  That is, effectively, read-write  
> access to
> everything.
>
> In the without-password case, you're giving similar access to anyone  
> that
> has access to the private key (though you can limit this to a given IP
> address in authorized_keys2).
>
> It goes further than this (ie. the sudo case is also giving that read-
> write access to the remote user running the backup command).  I'd  
> want to
> give this some careful thought before choosing.
>
> There's also the possibility of combining the two ideas.  The remote  
> user
> logs into a local non-root user.  This is done using a key pair, and  
> the
> local user has no password (so no password attacks on the local user
> account).  The key pair, via authorized_keys2, has access only to the
> "sudo rsync" command.

You may also want to consider a wrapper script to limit what the private
key allows access to on the machine which you are backing up.


Details on this procedure and also an example wrapper script are  
available
available from the following URL :

http://connect.homeunix.com/lbackup/network_backup

Good luck.