Preparation for adding offline signing support. Some additional
features and fixes are included as well:
- We make sure to add an empty SMIMECAP attribute instead of a populated
one to mimick pesign more.
- We switch to PKCS7_dataFinal() instead of PKCS7_final() as all that the
latter does is an unnecessary copy before calling PKCS7_dataFinal().
- We add support for passing in the signing time via $SOURCE_DATE_EPOCH.
Neither sbsign nor pesign set this flag in SpcPeImageData->flags,
which is about which resources should be included specifying "Which
portions of the Windows PE file are hashed." according to the
authenticode spec. However, this is followed by "Although flags is
always present, it is ignored when calculating the file hash for both
signing and verification purposes". So as it doesn't seem to do
anything useful and the other tools don't set any of these flags
either, let's follow suite and not set this flag ourselves either.
This new field allows specification of an fd on which the password
prompt logic will look for POLLHUP events for, and if seen will abort
the query.
The usecase for this is that when we query for a pw on behalf of a
Varlink client we can abort the query automatically if the client dies.
Let's gather generic key/certificate operations in a new tool
systemd-keyutil instead of spreading them across various special
purpose tools.
Fixes#35087
This allows loading the X.509 certificate from an OpenSSL provider
instead of a file system path. This allows loading certficates directly
from hardware tokens instead of having to export them to a file on
disk first.