Bug#896649: linux: Please enable CONFIG_DM_INTEGRITY

[Dwayne Litzenberger <dlitz@dlitz.net>]

Package: src:linux
Severity: wishlist

dm-integrity (introduced in Linux v4.12-rc1 and cryptsetup 2.0.0) 

cryptsetup 2.0.0 adds support for integrity-protected block devices 
(which was introduced in Linux v4.12-rc1), but support is not yet 
enabled in Debian kernels:

When loaded, a successful invocation looks something like this:

    # truncate -s 8M /tmp/dmtest
    # cryptsetup luksFormat --type luks2 --cipher chacha20-random --integrity poly1305 /tmp/dmtest

    WARNING!
    ========
    This will overwrite data on /tmp/dmtest irrevocably.

    Are you sure? (Type uppercase yes): YES
    Enter passphrase for /tmp/dmtest:
    Verify passphrase:
    Wiping device to initialize integrity checksum.
    You can interrupt this by pressing CTRL+c (rest of not wiped device will contain invalid checksum).
    Finished, time 00:00.088,    3 MiB written, speed  33.8 MiB/s

Currently, the initialization fails with the following error:

    device-mapper: reload ioctl on   failed: Invalid argument
    Cannot format integrity for device /tmp/dmtest.

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.15.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled