[dm-crypt] luks header on initramfs img

Milan Broz gmazyland at gmail.com
Fri Aug 8 15:22:33 CEST 2014

On 08/07/2014 06:16 AM, Milan Broz wrote:
> On 08/07/2014 03:09 AM, Henrique Abreu wrote:
>> I use to have a setup with luks header on a separate file, as describe here:
>> https://wiki.archlinux.org/index.php/Dm-crypt/Specialties#Encrypted_system_using_a_remote_LUKS_header
>> But since update from 1.6.4 to 1.6.5 it doesn't work anymore. It just keeps asking for the passphrase on and on without any error messages.
>> I noticed that, if I mount a usb drive and move the header from memory to the drive, then attempt to open again with the exact same command (below) it works:
>> # cryptsetup open --header header.img --type luks /dev/sda4 lvm
>> So, the difference is just where the header.img file is placed. For now, I have downgraded back to 1.6.4 to keep my boot setup simpler.
>> I rather use the header image inside initramfs if possible instead of having to mount a usb at boot just to read the header.
>> Does anyone know if that's intended for not working anymore or if it's a bug?
> There is no reason this should not work.
> (It could be bug elsewhere as well, 1.6.5 already uncovered 2 kernel bugs...)

Should be fixed in devel git (and in 1.6.6 which will be released in a few days).
(Basically I forgot to use wrapper for device open which avoids using O_DIRECT
if not supported, like in tmpfs.)

Thanks for report!


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