Comment 19 for bug 1898129

Verification done for focal-proposed (partman-crypto)
---

1) Booted the Ubuntu 20.04.1 Desktop ISO.
2) Launched a terminal, extracted the .udeb and copied over the crypto-base.sh file.
3) Performed installation to encrypted disk without the preseed option (default).
4) Performed installation to encrypted disk with the preseed option (testing).

On both cases, the installation finishes successfully, and the system can boot.
The LUKS header version is used as expected (LUKS2 by default, LUKS1 w/ option)

Details:
---

Launch terminal:

$ wget https://launchpad.net/ubuntu/+archive/primary/+files/partman-crypto_101ubuntu4.1_amd64.udeb
$ dpkg-deb -x partman-crypto_101ubuntu4.1_amd64.udeb udeb
$ sudo cp udeb/lib/partman/lib/crypto-base.sh /lib/partman/lib/crypto-base.sh

$ grep luksopts /lib/partman/lib/crypto-base.sh
 local mapping device cipher iv size pass luksopts
   luksopts="$RET"
   log "Additional options for luksFormat: '$luksopts'"
  log-output -t partman-crypto /sbin/cryptsetup -c $cipher-$iv -h $hash -s $size $luksopts luksFormat $device $pass

Launch ubiquity / Install Ubuntu 20.04.1 Desktop to Encrypted LVM device.
(In 'Installation type', select 'Erase disk and install Ubuntu', click in 'Advanced features', select 'Use LVM ...', select 'Encrypt ...', and move on to 'Install Now')

Launch terminal:

Without the option:

$ sudo debconf-get partman-crypto/luksformat_options
$

$ lsblk --ascii | grep -B1 crypt
`-vda6 252:6 0 8.8G 0 part
  `-vda6_crypt 253:0 0 8.8G 0 crypt

$ sudo cryptsetup luksDump /dev/vda6 | head -n2
LUKS header information
Version: 2

With the option:

$ sudo debconf-get partman-crypto/luksformat_options
--type luks1

$ lsblk --ascii | grep -B1 crypt
`-vda6 252:6 0 8.8G 0 part
  `-vda6_crypt 253:0 0 8.8G 0 crypt

$ sudo cryptsetup luksDump /dev/vda6 | head -n3
LUKS header information for /dev/vda6

Version: 1