[pkg-cryptsetup-devel] Bug#932437: LUKS formatting of a 16 MB (sic!) device is possible, open not

[Marc Haber]

Package: cryptsetup
Version: 2:2.1.0-5
Severity: normal

Hi,

I would like to luksFormat a really tiny device (which will only hold a
single file) with LUKS or LUKS2. I have been doing this multiple times
in the past, and was surprised that it doesn't work any more with
current cryptsetup.

I already had to go from 4 MB to 16 MB for the format to succeed, but
the 16 MB device cannot be luksOpened ("Requested offset is beyond real
size of device /dev/sdf2."). This applies to both LUKS and LUKS2.

With a 32 MB device, I could luks2Format _and_ luks2Open _and_ even USE
device ;-)  I didn't bother to try plain LUKS with that size then.

cryptsetup should be more clear about minimum space requirement, and it
should use them consistently. Having a minimum size is ok, if I know of
it, and being able to format but not open a device because it's too
small is a bug.

Greetings
Marc