Useful to extract a certificate from a hardware token to a file, for
example in mkosi to ship the certificate from a hardware token in
/usr/lib/verity.d in an image
Add verb that takes a PKCS#1 signature (plain rsa) as input and a
certificates, and outputs a PKCS#7 binary detached signature (p7s),
which is what the kernel dm-verity driver expects.
Co-authored-by: Luca Boccassi <bluca@debian.org>
Let's gather generic key/certificate operations in a new tool
systemd-keyutil instead of spreading them across various special
purpose tools.
Fixes#35087
