Re: [gentoo-user] Finalizing my backup system

[Michael Orlitzky]

On 10/06/2010 01:40 PM, Grant wrote:
>>> I'm using backupninja to backup data from my laptop, desktop, and
>>> remote server onto a remote desktop system.  backupninja is very
>>> simple and is really just an interface to a few other programs
>>> including rdiff-backup.  I'm not worried about a good restore method
>>> for now, I want to focus on keeping it simple and protecting my data.
>>> This is the first time I've set up a real backup system and I'd love
>>> to get some advice from you guys.  I've got a few questions.
>>>
>>> 1. This is the first time I've used passwordless SSH keys.  root on
>>> each system being backed up logs into the remote desktop as a normal
>>> user to store the backups.  Is this pretty safe?  I suppose if root is
>>> compromised on any of the three systems being backed up (via physical
>>> access or otherwise), the remote desktop will also be compromised as a
>>> normal user.  Maybe that normal user should be extraordinarily
>>> unprivileged?
>>
>> You can limit SSH access to only certain commands. On the remote desktop
>> machine, you probably had to add an entry to the SSH authorized_keys
>> file. You can prefix that line with the command that the user is allowed
>> to run. For example (I use rdiff-backup too):
>>
>>  command="/usr/bin/rdiff-backup --server",no-pty,no-port-forwarding
>>  ssh-rsa <big_ugly_key>
>
> I tried both that and simplified versions of it but it seems to
> prevent the login from working.  It hangs on the following command,
> which works if I don't add the above:
>
> ssh  -o PasswordAuthentication=no 1.2.3.4 -l user 'echo -n 1'

That's the point? You can't log in (run /bin/bash) or do anything except
the command listed in the authorized_keys file.


> Should it be working?  I noticed I have ssh-dss instead of your ssh-rsa.

That's just the key type, doesn't matter.