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What is an "un-encrypted pass through device"?

dkarrdkarr Posts: 40
in LFS201 Class Forum

I'm reading chapter 10. I got to Knowledge Check 10.1. This requires ordering the steps for setting up an encrypted partition.

All of the steps in this question are mentioned in the earlier text, except for "Create the un-encrypted pass through device". I've read the section over again, and I don't see anything like this mentioned.

Comments

  • JasePow68JasePow68 Posts: 4
    Here's a nice explanation:
    http://homepage.smc.edu/morgan_david/linwin/freeotfe.htm
  • coopcoop Posts: 307
    It's been a while since I looked at this and the Knowledge Checks were added later, but I think it just means the underlying device; i.e., the partition or loop back file.
    so that means using fdisk on something to create a partition, or if it is lvm, lvcreate, or if it is a loopback file, losetup.

  • dkarrdkarr Posts: 40
    In that KC, it expects the following order:
    1. Create a partition for the encrypted block device
    2. Format with cryptsetup
    3. Create the un-encrypted pass through device
    4. Format with a standard filesystem such as ext4
    5. Mount the filesystem on the encrypted block device

    After step 1, the partition is already created. So, I'm guessing that if this "un-encrypted pass through device" is a real thing, it's not created by creating the partition.

    Note that lab 10.1 mentions this also.
  • luisviveropenaluisviveropena Posts: 334
    Hello,

    The following step:

    "Create the un-encrypted pass through device"

    Refers to the luksOpen command, as in here:

    $ sudo cryptsetup luksOpen /dev/sda4 secret-disk

    Regards,
    Luis.
  • dkarrdkarr Posts: 40
    I suppose that's logical, as that's the only step that doesn't appear to correspond to a description, and it comes between the other two steps, but can you elaborate a little more on this? How exactly is this a "un-encrypted pass through device"?
  • luisviveropenaluisviveropena Posts: 334
    Hi,

    I haven't heard that expression before, but I think that a "pass through device" refers to a kind of converter mechanism. So in this case the luksopen command creates a mapping through a device, so it becomes "un-encrypted".

    Regards,
    Luis.
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