R: Re: R: Re: CAN GRUB DO WRITING OPERATIONS ON ATTACHED DRIVES ?

[address@hidden]

Dear Colin,

I apologize with you. I've used uppercase letter to only put in evidence my question. I had no intention to shouting. 

Thank very much.

Your reply is what i was looking for.

Best Regards.

Vincenzo.


Forensic Consultant
Tribunale di Lecce

Studio: Strada di Garibaldi - Contrada Paradisi
73010 Lequile (LE)

cell: 339.7968555
skype: vincenzo.di_salvo


> ----Messaggio originale----
> Da: address@hidden
> Data: 17-lug-2017 19.48
> A: <address@hidden>
> Ogg: Re: R: Re: CAN GRUB DO WRITING OPERATIONS ON ATTACHED DRIVES ?
>
> On Mon, Jul 17, 2017 at 07:21:49PM +0200, address@hidden wrote:
> > CAN GRUB IMPLICITLY WRITE TO A DRIVE ATTACHED TO A COMPUTER ?
> > 
> > Implicitly means: without an explicit command from a user.
>
> Please stop SHOUTING; it's generally considered rather rude.
>
> GRUB intentionally has no general filesystem writing support.  As far as
> I'm aware there are exactly four ways for it to send any write commands
> to disks:
>
>  1) The "save_env" command (grub-core/commands/loadenv.c) which writes
>     key/value pairs to a small preallocated region of disk.  This is
>     used to communicate small amounts of information to the OS, such as
>     whether the last request to boot a particular menu entry on only the
>     next boot has been completed.
>
>  2) The "gptsync" command (grub-core/commands/gptsync.c), which does
>     some MBR/GPT partition table mangling needed on some Apple models.
>
>  3) The similar "mactelbless" and "macppcbless" commands
>     (grub-core/commands/macbless.c), which configure a file/directory on
>     some Apple filesystems to be the 'blessed' boot image for that
>     filesystem.
>
>  4) The "parttool" command (grub-core/commands/parttool.c,
>     grub-core/parttool/), which can be used to make various
>     modifications to MBR partition table entries.
>
> GRUB is scriptable, so it isn't possible to give a general answer to
> your question for all systems that might have custom configurations, but
> the default configuration files only use the "save_env" and "parttool"
> commands, the latter only in the case where a chainloadable operating
> system was detected on a disk using the MBR partition table format.  In
> either case, it isn't going to write to a random USB device that's
> attached to a machine, although save_env might write to the device it
> believes holds /boot/grub/grubenv.
>
> The low-level disk handling code is in grub-core/disk/.
>
> -- 
> Colin Watson                                       address@hidden
>
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