Hi,

both systemd and cryptsetup provide a man page for /etc/crypttab (man 5
crypttab).

The systemd version version can be found at
https://www.freedesktop.org/software/systemd/man/crypttab.html#

Atm, we remove that man page in Debian:
https://salsa.debian.org/systemd-team/systemd/-/blob/debian/master/debian/rules#L254
to avoid a file conflict, when cryptsetup is installed.

This is unfortunate though. Since systemd is our default init system,
the man page for /etc/crypttab should reflect what's supported.

Do you have a suggestion, how we can resolve this?
I notice, that the crypttab man page in src:cryptsetup is a Debian
specific addition (debian/doc/crypttab.xml).

Would it be possible, to rename that man page (say crypttab_debian) and
add a paragraph, that the information there is mainly relevant for
non-systemd systems (and initramfs-tools)?

Regards,
Michael

Hi Michael,
initramfs-tools, and AFAIK the only “guided” way to get disk encryption
from d-i/partman-crypto yields something involving cryptsetup-initramfs
only, not systemd-cryptsetup@.service.  I don't have metrics of course,
but I therefore believe that crypttab(5) from src:cryptsetup is more
likely to be relevant to users than the one from systemd.

We're upstream for the stuff that hook into initramfs-tools for
unlocking at initramfs stage (and also the sysvinit scripts).

In mid-2018 we added a section “on different crypttab formats”
explaining the scope of our manual page and even included a pointer to
https://www.freedesktop.org/software/systemd/man/crypttab.html .  If
systemd were to ship its crypttab manual under a different name or
location we could add the offline URL there too.

Cheers,

Am 30.01.21 um 19:23 schrieb Guilhem Moulin:

Do I take it, that you do not consider renaming the Debian specific
crypttab man page an option?

Hi Michael,

Correct: as written earlier I believe the current manual is more likely
to be useful for our users (given initramfs-tools is our default
initramfs and someone choosing “encrypted disk” at d-i stage will end up
using cryptsetup-initramfs and not involve systemd when unlocking).

Unfortunately systemd's crypttab(5) parsing logic and list of known
options started as a strict subset of ours (see for instance #618862),
then evolved in its own direction.  (And so did we, to a lesser extent.)
However the options that are known not to be working with systemd are
marked as such in the manual.

Cheers,