Re: [PATCH] 90crypt: keys on external devices support

[Karel Zak <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Thu, Oct 21, 2010 at 02:54:54PM +0100, Mr Dash Four wrote:
>
>>>   rd.luks.key=<key_path>:<key_dev>:<key_dev_fs>:<luks_dev>
>>>     
>>
>>  The LABEL and UUID are always stored in filesystem specific
>>  superblock (or root directory) on the device. It means that your
>>  system has to be able to detect FS type before it's able to read
>>  LABEL/UUID from the device.  The <key_dev_fs> is unnecessary.

Well, rephrasing: The <key_dev_fs> is unnecessary if you want to use
UUID or LABEL.

> If I have HFS drive (Mac) or even HPFS (OS/2) and have the keys there  
> how would I be able to retrieve them then if I do not use labels/UUID -  
> by using /dev/sdXX?

HFS, HPFS and NTFS support labels and uuids

> I think specifying the target file system is important because by just  
> executing 'mount' without indicating the target file system when I have,  
> for example, HFS or HPFS mount just won't happen.

Why? My mount(8) is able to detect HFS or HPFS.

# losetup --show -f /home/images/filesystems/hfs.img
/dev/loop0

# mount /dev/loop0 /mnt/test

# grep loop0 /proc/mounts 
/dev/loop0 /mnt/test hfs rw,relatime,uid=0,gid=0 0 0


> I am also not certain  
> that by just executing 'mount' it would automatically map NTFS either,  
> without specifying that the target system is NTFS (the command in  
> question for mounting NTFS partitions is ntfs-3g isn't it?).

 $ ll /sbin/mount.ntfs
 lrwxrwxrwx 1 root root 13 Oct  8 10:32 /sbin/mount.ntfs -> mount.ntfs-3g

    Karel

-- 
 Karel Zak  <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
 http://karelzak.blogspot.com