forked from unom/punktfunk
enricobuehlerandClaude Opus 5
a49858f194
The drivers had no cryptographic identity at all. Every build minted a fresh `CN=punktfunk-driver` cert (build-pf-vdisplay.ps1, build-gamepad-drivers.ps1), and install.rs `trust_cert` adds whatever .cer it finds in the unpacked bundle to machine Root AND TrustedPublisher. So the signature vouched for nothing an attacker couldn't restage — replace the bundle, ship your own cert beside your own driver, install proceeds identically. It was ceremony to make PnP install quietly. Worse, it leaked. `trust_cert` runs once per driver (install.rs:102 and :155), so every upgrade added TWO more self-signed root CAs under the same name, and nothing ever removed them: uninstalling punktfunk left trust behind that the user had no reason to keep granting. So: both build scripts now take a stable cert via DRIVER_CERT_PFX_B64 (they already read the env var — windows-host.yml just never passed it) and fail closed on a v* tag, same rule as the host and MSIX packers. `driver uninstall` purges every `CN=punktfunk-driver` cert from both stores, and `driver install` purges before adding, so an upgrade also collects the historical pile instead of adding to it. Purge-before-add lives ONLY on the pf-vdisplay install path, not the gamepad one. The installer runs vdisplay first and gamepad second; purging in both would have the gamepad leg delete the cert the vdisplay leg just added whenever the two bundles carry different certs — which is exactly what canary's per-build fallback produces. Purging by subject rather than thumbprint is deliberate too: it is what lets one install clean up certs from builds that no longer exist anywhere, and it needs no parsing of certutil's localized output (this module exists because locale-parsed PowerShell broke the driver install on a German box). This does NOT make the driver download authenticated — a self-signed leaf is its own root, so the installer must trust it for the driver to install at all. What it buys is a fingerprint we can publish out-of-band so a substituted driver is detectable, an allowlistable publisher, continuity across releases, and no root accumulation. Attestation signing remains the real fix; documented as such. Documented the key-custody trade honestly in packaging/windows/README.md: a stable key trusted as a machine root on every install is worth stealing in a way a throwaway never was, with no revocation path. CI secret only. ⚠️ The secrets must exist before the next v* tag or the release will fail — that is the guard working, and the generation runbook is in that README. The fingerprint line there is a placeholder until the key is generated. Verified: punktfunk-host compiles clean on the windows-amd64 runner with this install.rs (exit 0, no warnings); both build scripts parse; cargo fmt clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>