ср, 5 янв. 2022 г. в 01:07, Glenn Washburn <development@efficientek.com>:

> On Tue, 4 Jan 2022 15:42:22 -0600
> Glenn Washburn <development@efficientek.com> wrote:
>
> I'm generally very pro-flexibility, but I'm not sure I like this from a
> user perspective. For the common case, which is detached headers in a
> file, this will cause the user to do more work (create a loopback
> device of the file). What's a reasonable scenario where a user would
> want the detached header on a device as opposed to a file system? Am I
> correct in thinking that you use such functionality?
>

Actually no, I only use a file for the external header, not a disk.
I have now looked at the patches again and will try to state my point of
view in
more detail:

I don't think the hdr_file field as it stands in the patch set is relevant.
I mean
the hdr_file field of type grub_file_t in the grub_cryptomount_args
structure.
Even the grub_disk_t type may not be relevant here. You could only pass
a header file name or a disk name (as char*) through this structure. This
would
reflect the essence of this structure, but further implementation the code
will
not be pretty in this case.

I still suggest expanding the number of parameters for the recover_key
function
and use grub_disk_t to pass the header from the user directly.

I'll leave it here for your reference:
https://gitlab.com/reagentoo/grub/-/blob/0921badcf817071639058bc4a534c8e6bd05f212/grub-core/disk/luks2.c#L545

header_source is equal source - if we are not using external header


>
> I do like that it simplifies the code. An alternative route to get the
> same simplification while still being given a file path as an argument
> to cryptomount would be to internally create a loopback device and use
> that instead of passing a file around. A possible undesirabe
> side-effect, this might require being dependent on the loopback module.
>
> Glenn
>
> >
> > >  };
> > >  typedef struct grub_cryptomount_args *grub_cryptomount_args_t;
> > >
> > > diff --git a/include/grub/file.h b/include/grub/file.h
> > > index 31567483c..3a3c49a04 100644
> > > --- a/include/grub/file.h
> > > +++ b/include/grub/file.h
> > > @@ -90,6 +90,8 @@ enum grub_file_type
> > >      GRUB_FILE_TYPE_FONT,
> > >      /* File holding encryption key for encrypted ZFS.  */
> > >      GRUB_FILE_TYPE_ZFS_ENCRYPTION_KEY,
> > > +    /* File holding the encryption metadata header */
> > > +    GRUB_FILE_TYPE_CRYPTODISK_DETACHED_HEADER,
> > >      /* File we open n grub-fstest.  */
> > >      GRUB_FILE_TYPE_FSTEST,
> > >      /* File we open n grub-mount.  */
> >
> > Dmitry
>