The security hooks returned their own errors for calls the shim can't
verify, instead of passing them to the original firmware hooks. The
Security2 hook rejected a missing device path or file buffer, which are
optional in the PI specification, and a boot policy of TRUE. The
Security hook returned NOT_FOUND for any file it couldn't read, like
one in a firmware volume.
Pass these calls to the original hook, which is what the firmware does
without the hook installed. This matches systemd-boot, and the
firmware still enforces its own verification, so nothing is let
through that the firmware would reject.
The firmware passes BootPolicy as a UEFI BOOLEAN (a u8). Declaring it
as a Rust bool in the extern signature is undefined behavior for any
value other than 0 or 1. Use uefi_raw::Boolean instead.
If the security hook was installed while already installed, the
protocols contained Sprout's own handlers, which were then saved as the
"original" handlers. A verification failure would then call back into
the hook forever. Keep the existing saved state in that case.
alex