[pkg-cryptsetup-devel] Bug#491867: closed by Jonas Meurer <mejo at debian.org> (Bug#491867: fixed in cryptsetup 2:1.0.6-4)

[Helmut Grohne]

severity 491867 minor
thanks

> > So this will run mkswap on the resume device.
> AFAIK, this mkswap operation is run by "/etc/init.d/cryptsetup-early"
> which in turn is run by "/sbin/init". Thus, this operation is only
> during a regular boot. It is not run during resume, since resume does
> not actually run init scripts.

With only reading I come to the same conclusion.

> In particular, I could find no copy of the crypttab file in the
> initrd.img which hands over to the unfrozen system.

Still this information has to be somewhere in the initrd, because
otherwise the initrd would have no way to know what to decrypt. I guess
the file is parsed and stored somewhere in conf/. What gives more
evidence is that neither /usr/share/initramfs-tools mentions mkswap nor
the initrd contains a copy.

> Has this fix actually caused a problem with any system?

Actually no, I did not trash my system. I only verified that the swap
signature does change and that the luks header is not properly
destroyed. I then concluded under the false assumption that cryptsetup
behaves consistent.

So let me propose changing other things:
 * First of all it would be great if we could change man crypttab to
   reflect this behaviour like "Run mkswap on the created device, but
   not before /sbin/init is run." or "Run mkswap on the created device
   unless it is used for resuming."
 * Secondly in README.initramfs.gz according to my understanding step 6
   should be useless, because step 4 already formated the device. A imho
   better approach would be to keep step 6 and never let cryptsetup
   invoke mkswap by removing that swap option if this change does not
   break the sequence in another way.

I'd also be glad if README.initramfs.gz could be extended with more
explanations on why and how this works, because the documentation of
cryptsetup often made me read the source.

Thanks for investigating this

Helmut