After further investigation. The module signing / cert management is as follows:
- During the kernel build, a unique pub/priv key is generated (using info in kernelsource/x509.genkey):
- All certificates in kernel source dir (files with the .x509 extension) are signed with the per-kernel key and included in the default trust chain.
- All kernel modules are signed with the signing_key and thus any module signed with those would also be acceptable.
NOTE:
CentOS does not sign any of the provided kmod-* packaged modules.
By latest, do you mean latest kernel for Ubuntu 20.04 LTS, or kernel on latest Ubuntu 21.04 ?