[dm-crypt] LUKS GPT GUID

Milan Broz gmazyland at gmail.com
Sun Jan 26 10:24:39 CET 2014


On 01/26/2014 02:40 AM, Pali Rohár wrote:
> Hello,
> 
> according to wikipedia [1] and other sites (e.g. [2]) MBR partition ID
> for LUKS is E8. I tried to find GPT partition GUID for LUKS, but there
> is nothing on wikipedia [3] nor google... So has LUKS already
> preferred/assigned GUID for GPT partition table? There is already GPT
> GUID for linux data, raid, swap, lvm and home partitions (see [3]), so
> I think that LUKS should have GUID too.

Hi,

this is wonderful... who assigned E8 type? I thought LUKS has no assigned
partition type and also I doubt LVM2 type is properly assigned too
(it is probably form the LVM1 age when it was implemented in-kernel directly
and partition type was important to detect it.) But not sure about this.

Anyway, today partition type is ignored (both in LVM and LUKS), so it is really
just for convenience for other applications.
(Anyway, code should always use (lib)blkid to detect what's really on the device,
not trust partition id.)

For GPT GUID, I would like to know how these GUID codes appeared in libfdisk
and how this was standardized for LVM. LUKS should have GUID too then...
(cc to Karel as util-linux/libfdisk maintainer ;-)

If this is really used, both should be documented in LUKS specification.

Thanks,
Milan

> 
> [1] - http://en.wikipedia.org/wiki/Partition_type
> [2] - http://www.win.tue.nl/~aeb/partitions/partition_types-1.html
> [3] - http://en.wikipedia.org/wiki/GUID_Partition_Table



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