I wanted to install Debian Linux after a weird journey with Gentoo Linux. My partition layout is this:

  • Boot Partition (512 MiB, mount at /boot)
  • Swap Partition (4 GiB)
  • Root Partition (~80 GiB, mount at /)
  • Home Partition (~170 GiB, mount at /home, LUKS encrypted)

While trying to preserve the home partition, I think I clicked ‘Configure encrypted partitions’ on the Debian installer and then set a password for it (the same that it had before).

Now, I can unlock it like before, but after it is unlocked, no utility recognizes the filesystem (ext4) and the file command reports it as being data:

# file -s -L /dev/mapper/home
/dev/mapper/home: data

file on the encrypted partition returns the following:

# file -s /dev/nvme0n1p4
/dev/nvme0n1p4: LUKS encrypted file, ver 2, header size 16384, ID 3, algo sha256, salt 0x590d84c0e8397ad0..., UUID: c5ff37db-11f7-4ccf-8869-c4bc22648202, crc 0x345f75d85c9f444a..., at 0x1000 {"keyslots":{"0":{"type":"luks2","key_size":64,"af":{"type":"luks1","stripes":4000,"hash":"sha256"},"area":{"type":"raw","offse

(This is the complete output, it cuts at offset for some reason)

My luksDump output is this:

# cryptsetup luksDump /dev/nvme0n1p4
LUKS header information
Version:       	2
Epoch:         	3
Metadata area: 	16384 [bytes]
Keyslots area: 	16744448 [bytes]
UUID:          	c5ff37db-11f7-4ccf-8869-c4bc22648202
Label:         	(no label)
Subsystem:     	(no subsystem)
Flags:       	(no flags)

Data segments:
  0: crypt
	offset: 16777216 [bytes]
	length: (whole device)
	cipher: aes-xts-plain64
	sector: 512 [bytes]

Keyslots:
  0: luks2
	Key:        512 bits
	Priority:   normal
	Cipher:     aes-xts-plain64
	Cipher key: 512 bits
	PBKDF:      argon2id
	Time cost:  6
	Memory:     1048576
	Threads:    4
	Salt:       18 b4 a6 e9 87 1f 94 f6 7d 96 f2 9c 0f 2e ca 75 
	            e6 0f 80 7d 09 70 40 19 d0 a4 a1 49 ff 5c 1c 0b 
	AF stripes: 4000
	AF hash:    sha256
	Area offset:32768 [bytes]
	Area length:258048 [bytes]
	Digest ID:  0
Tokens:
Digests:
  0: pbkdf2
	Hash:       sha256
	Iterations: 171785
	Salt:       c2 b0 a6 f5 e1 bf 5f 85 82 b1 d5 f3 10 c6 ae b7 
	            7c fc 50 41 c5 a6 03 f6 5a bd ac df 46 89 7b c6 
	Digest:     57 7d fb 87 69 c5 58 07 cf 82 88 5e f8 c6 39 f5 
	            7d 00 ec 07 e0 df b8 ee b5 dd ff 20 bf b3 bc 01

My guess is that I re-encrypted the already encrypted partition. Also, I noticed that the UUID changed. Can anyone help me recover it? Thanks in advance.

If you need more logs, I will happily provide them to you.

  • @[email protected]
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    7 months ago

    I’ve been bit by this, it has been an issue for a long time. For a while it also affected Ubuntu but I don’t know if that’s still the case.

    Rather than decrypting the existing luks partition like pretty much every other distro, the Debian installer will create a new one using that key. Additionally, the installer does not cache the information and apply it when you finalize partitioning, it will apply the encryption immediately and then allow you to partition on top of it. Instant data loss.

    It is possible to reuse an existing luks partition, but you must unlock and mount it manually before partitioning in the installer. This isn’t something I’d expect anyone to know beforehand, since it’s different than everything else.

    Edit: apparently a very long time https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=451535