[dm-crypt] /sbin/cryptsetup: not found on boot after Grub repair - manual mounting works

Sven Eschenberg sven at whgl.uni-frankfurt.de
Thu May 26 01:13:10 CEST 2016



Am 26.05.2016 um 00:17 schrieb Arno Wagner:
> On Wed, May 25, 2016 at 21:25:15 CEST, Sven Eschenberg wrote:
>> You are welcome.
>
> Valid questions that come with a reasonable atempt to
> give good information are always welcome.
>
>> Blame it on bad documentation.
>
> One of the things where FOSS is often not better than
> commrcial software, unfortunately.

Unfortunately, yes. I think the need of proper documentation and the 
effort needed to provide one is often strongly underestimated. You know, 
people tend to to say: Ah, that error is never gonna happen, I'll save 
the time for safety checks for now, maybe do it later - somewhen. 
Similarily they go: No need to document this, the user will never need 
that info. Because it is something the user will/should never be 
bothered with. Except, it will happen, eventually.

>
>> Figuring this out just by reading the
>> error message is a pretty tough one ;-). Simply put:
>> update-initramfs expects to be run in a chroot that exactly matches
>> the system after a normal boot (this is not limited to cryptsetup),
>> otherwise automagic fails hard during detection and creates major
>> desaster.
>
> Indeed. Automagic becomes automess there. The idea to configure
> the initramfs to exactly what is currently running in that chroot
> is valid, but it should come with very clear warnings that
> things are done this way.

The task of figuring out how to bring up '/' is indeed not trivial and 
the assumptions made are absolutely valid. But as you already stated, it 
is important to point this out precicsely at the right places and 
possibly implement safe fallbacks, whenever possible.

The error output could certainly be improved. I have to admit though, 
there was no run of update-initramfs with verbose output (I think). 
Maybe a verbose output might have cleared things up a little.

>
> Regards,
> Arno
>

Regards

-Sven


>>
>> Regards
>>
>> -Sven
>>
>> Am 25.05.2016 um 20:25 schrieb Aaron:
>>> Thank you Sven, that was extremely helpful. Thank you also to Hugh and
>>> Arno for their replies.
>>>
>>> You were correct, this was caused by my mounting the encrypted
>>> filesystem under a different name (the UUID), rather than sda6_crypt.
>>>
>>> Full step-by-step commands of how I fixed this are here:
>>> https://answers.launchpad.net/ubuntu/+source/cryptsetup/+question/293750
>>>
>>> Thanks again!
>>>
>>> Aaron
>>>
>>> On 22/05/16 02:34, Sven Eschenberg wrote:
>>>> Hi there,
>>>>
>>>> This seems to be the relevant part:
>>>> device-mapper: table ioctl on sda6_crypt failed: No such device or
>>>> address
>>>> Command failed
>>>> cryptsetup: WARNING: failed to determine cipher modules to load for
>>>> sda6_crypt
>>>>
>>>> It basically tells you your cryptodevice is missing and thus no info
>>>> could be grabbed which in turn does not include cryptsetup etc. into
>>>> your initramfs.
>>>>
>>>> When booting into the live system, unlock and mount your stuff before
>>>> chrooting and make sure that all the mapper names are EXACTLY as
>>>> expected by mkinitramfs (update-initramfs). ESP: Consult your crypttab
>>>> file to find the name. Once the mapped device (as noted in crypttab)
>>>> can be found running update-initramfs should work and include
>>>> everything that is needed.
>>>>
>>>> Regards
>>>>
>>>> -Sven
>>>>
>>>> P.S.: If I am not mistaken your mapping is supposed to be called
>>>> sda6_crypt, while bootrepair gave it a UUID-based name. So you'll
>>>> probably have to work this through manually, I guess.
>>>>
>>>>
>>>> Am 21.05.2016 um 16:14 schrieb Aaron:
>>>>> Hello,
>>>>>
>>>>> I would really appreciate any help to make my system boot properly
>>>>> again. I can manually mount my encrypted partitions and they unlock
>>>>> correctly, so I'm pretty sure that I haven't lost my data, but something
>>>>> that used to work in the Ubuntu 16.04 boot process to unlock and boot
>>>>> the partitions must have broken, as whenever I boot now, typing my
>>>>> password no longer unlocks and boots Ubuntu. Instead it says:
>>>>> “cryptsetup: cryptsetup failed, bad password or options?”
>>>>>
>>>>> If I press escape and get to the console output, it says:
>>>>> /scripts/local-top/cryptroot: line 1: /sbin/cryptsetup: not found over
>>>>> and over.
>>>>>
>>>>> In case the history is relevant, I recently had to reinstall Windows on
>>>>> a dual-boot machine. That meant that I had to use boot repair to get my
>>>>> Grub back. I now have what seems to be a working Grub, but when I boot
>>>>> into Ubuntu and enter my password into the “Please unlock disk
>>>>> sda6_crypt”, it fails as described.
>>>>> http://paste.ubuntu.com/16443425/
>>>>> was the output of the boot-repair reconfiguration of Grub.
>>>>>
>>>>> I booted in with a live CD and chrooted into my installation. I did an
>>>>> apt-get update and apt-get upgrade and I see the following in the
>>>>> output:
>>>>> Processing triggers for initramfs-tools (0.122ubuntu8) ...
>>>>> update-initramfs: Generating /boot/initrd.img-4.4.0-22-generic
>>>>> device-mapper: table ioctl on sda6_crypt failed: No such device or
>>>>> address
>>>>> Command failed
>>>>> cryptsetup: WARNING: failed to determine cipher modules to load for
>>>>> sda6_crypt
>>>>>
>>>>> I asked for help here:
>>>>> https://answers.launchpad.net/ubuntu/+source/cryptsetup/+question/293750
>>>>> but nobody has had any ideas so far.
>>>>>
>>>>> Any ideas would be greatly, greatly appreciated.
>>>>>
>>>>> Kind regards,
>>>>>
>>>>> Aaron
>>>>> _______________________________________________
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>>>>> dm-crypt at saout.de
>>>>> http://www.saout.de/mailman/listinfo/dm-crypt
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