Re: Grub dd?

[Endres]

Hi,

could mean a possible security vulnerability. In case there are no other
boot devices available, as well as no custom kernel options allowed in
the boot line, dd still would offer to dump data from devices.

So, I am not sure if that is something that grub should be able to do.
At least I would recommend to add it as a "default-off" feature.

Cheers,
Endres

On 11/21/21 4:26 AM, Peter Xu wrote:
> Hi, Grub list,
> 
> I found there's no "dd" command for grub.  Is there a reason?
> 
> Asked because I think it could be really handy to be able to do that
> with grub.  For example, a simple use case is we can backup root
> partition somewhere on a backup disk before hand, then if the real root
> partition corrupted for some reason we can always dd it back within grub
> loader.  It could be helpful when it's non-trivial to attach a USB live
> image to the system so we can't initiate "dd" in a live Linux distro.
> 
> I'm actually thinking of some way to allow the root fs to be recovered
> from a "snapshot" by dd-ing from a backup block device before loading
> linux and everything, for every single time the system boots.  Then we
> guarantee every time we boot into the system we'll always see the same
> content for root fs.  Not sure whether that can be easily done with
> current grub.
> 
> Thanks,
>