cryptsetup 2.7.0 adds feature to link effective volume key in custom
kernel keyring during device activation. It can be used later to pass
linked volume key to other services.
For example: kdump enabled systems installed on LUKS2 device.
This feature allows it to store volume key linked in a kernel keyring
to the kdump reserved memory and reuse it to reactivate LUKS2 device
in case of kernel crash.
Since EC keys doesn't support encryption directly, we use ECDH protocol.
We generate a pair of EC keys in the same EC group, then derive a shared secret using the generated private key and the public key in the token.
The derived shared secret is used as a volume key. The generated public key is stored in the LUKS2 JSON token header area. The generated private key is erased.
To unlock a volume, we derive the shared secret with the stored public key and a private key in the token.
Co-authored-by: MkfsSion <mkfssion@mkfssion.com>
The header and keyfile are necessary only for opening the device, not
for closing, so it is not necessary to deactivate the generated
cryptsetup unit when the header or keyfile backing store are removed.
This is especially useful in the case of softreboot, when the new
mount root is setup under /run/nextroot/ but we don't want to close
the cryptsetup devices for encrypted /var/ or so, and we simply
mount it directly on /run/nextroot/var/ before the soft-reboot.
As pointed out in https://github.com/systemd/systemd/issues/29814, we need to
use phrases are are meaningful on their own, because the man page formatter
creates a list at the bottom. With <ulink>see docs</ulink>, we end up with:
NOTES:
1. see docs
https://some.url/page
2. see docs
https://some.url/page2
which is not very useful :(
Also, the text inside the tag should not include punctuation.
Python helper:
from xml_helper import xml_parse
for p in glob.glob('../man/*.xml'):
t = xml_parse(p)
ulinks = t.iterfind('.//ulink')
for ulink in ulinks:
if ulink.text is None: continue
text = ' '.join(ulink.text.split())
print(f'{p}: {text}')
As I noticed a lot of missing information when trying to implement checking
for missing info. I reimplemented the version information script to be more
robust, and here is the result.
Follow up to ec07c3c80b
This tries to add information about when each option was added. It goes
back to version 183.
The version info is included from a separate file to allow generating it,
which would allow more control on the formatting of the final output.
(s) is just ugly with a vibe of DOS. In most cases just using the normal plural
form is more natural and gramatically correct.
There are some log_debug() statements left, and texts in foreign licenses or
headers. Those are not touched on purpose.
In most cases we refernced the concept as "initrd". Let's convert most
remaining uses of "initramfs" to "initrd" too, to stay internally
consistent.
This leaves "initramfs" only where it's relevant to explain historical
concepts or where "initramfs" is part of the API (i.e. in
/run/initramfs).
Follow-up for: b66a6e1a58
Handle the case where TPM2 metadata is not available and explicitly
provided in crypttab. This adds a new "tpm2-pin" option to crypttab
options for this purpose.
Use the option name 'password-echo' instead of the generic term
'silent'.
Make the option take an argument for better control over echoing
behavior.
Related discussion in https://github.com/systemd/systemd/pull/19619
