Re: Error while unlocking encrypted BCacheFS: Required key not available

[Martin Steigerwald <martin@lichtvoll.de>]

Martin Steigerwald - 07.01.24, 12:22:53 CET:
> Hi!
> 
> Kernel 6.7.0-rc8 with BCacheFS new year fixes. Compliled with Debian gcc
> 13.2.0-9.
> 
> BCacheFS tools 1.3.3 – according to bcachefs version – from Debian
> package bcachefs-tools 24+really1.3.4-2.
> 
> Linux kernel keyutils from Debian package keyutils 1.6.3-2+b2. (Not sure
> whether really required.)
> 
> Created BCacheFS on external 4 TB SSD:
> 
> % mkfs.bcachefs -L […] --data_checksum xxhash --metadata_checksum xxhash
> --compression=lz4 --encrypted /dev/sda1
> 
> (also tried without xxhash, no difference)
> 
> 
> Unlock attempt with incorrect passphrase:
> 
> % bcachefs unlock /dev/sda1
> Enter passphrase:
> incorrect passphrase
> 
> Unlock attempt with correct passphrase does not yield error message
> "incorrect passphrase". Key seems to be available:
> 
> % grep bcachefs /proc/keys
> 1b9e7153 I--Q---  1 perm 3f010000  0  0 user   bcachefs:[… UUID …]: 32

Also keyctl sees the key in root user keyring:

% keyctl list @u
1 key in keyring:
463368531: --alswrv     0     0 user: bcachefs:[… UUID …]

In case this is an issue with Debian packaging of bcachefs-tools I can 
report there.

> UUID matches filesystem.
> 
> 
> Still I get:
> 
> % LANG=en mount /dev/sda1 /mnt/zeit
> mount: /mnt/zeit: mount(2) system call failed: Required key not
> available. dmesg(1) may have more information after failed mount system
> call.
> 
> % dmesg | tail -1
> [105441.695035] bcachefs ([…]): error requesting encryption key: ENOKEY
> 
> 
> Why? And how to fix it?
> 
> I found
> 
> error requesting encryption key #93
> 
> https://github.com/koverstreet/bcachefs/issues/93
> 
> But I am not sure whether it applies to my situation.
> 
> I use Devuan with elogind. Do I need that pam related configuration
> change from comment
> 
> https://github.com/koverstreet/bcachefs/issues/93#issuecomment-609430340
> 
> ?
> 
> I do not like to do it in case it is not required.
> 
> Best,


-- 
Martin