Re: [rdiff-backup-users] Security problem with rdiff over ssh?

[Jakob Unterwurzacher]

On 28/05/10 01:23, Aneurin Price wrote:
> On Thu, May 27, 2010 at 23:00, feffer
> <address@hidden> wrote:
>>
>> I'm running rdiff-backup over ssh with an unattended cron script using an 
>> ssh key-pair proceedure described here 
>> (http://arctic.org/~dean/rdiff-backup/unattended.html). My script works 
>> fine, but I'm wondering about security. It is generally considered a bad 
>> idea to allow root login to ssh, but I cannot preserve ownership and 
>> permissions if I disallow root login.
>>
>> Is this really a problem since my machines are behind a router on my LAN? 
>> The ssh key-pairs are not password protected, but isn't the only real 
>> security threat losing the private key?

Unless you lose the private key, this is secure. But double-check that
root can login *only* using the key
(set
 PermitRootLogin without-password
or even
 PermitRootLogin forced-commands-only
in sshd_config, more info: http://linux.die.net/man/5/sshd_config )

>>
>> Is there a way to lock this down a bit more while still enabling unattended 
>> backups?
>>
> 
> Do you really need the permissions on the server to be set correctly,
> rather than simply when you restore? If not, I thought rdiff-backup
> could save and restore permissions separately from the files in
> question, allowing you to record them without needing to be root.

While it is true that rdiff-backup will save the metadata somewhere else
then, this means that you cannot restore by simply copying the files.
This means if your rdiff-backup-data folder is corrupt (happens!), you
are screwed. I'd recommend running as root on the destination server.

> Alternatively you could use metastore
> (http://david.hardeman.nu/software.php) which can save file metadata
> to a file, allowing you to restore it at a later date.
> 
> Both of these still require root privileges on the client machine when
> backing up (unless everything is world-readable) and when restoring in
> order to reset the permissions, but not on the destination machine.
> 
> Nye
> 
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