Files
certctl/internal
shankar0123 1dd1dd4e0a wincertstore: pre-deploy snapshot + on-import-failure rollback
Closes Bundle 7 of the 2026-05-02 deployment-target coverage audit
(see cowork/deployment-target-audit-2026-05-02/RESULTS.md). Pre-fix,
DeployCertificate at wincertstore.go:162-215 ran a single PowerShell
script that imported the PFX, optionally set FriendlyName, and
optionally removed expired same-Subject certs. Import-PfxCertificate
is atomic at the cert-store level, but the wider sequence (import →
friendly name → remove expired) is not. Failure in any post-import
step left the new cert in the store with no clean recovery path.
docs/deployment-atomicity.md L93 promised "Get-ChildItem snapshot
for rollback"; the code didn't deliver.

This commit:

1. Pre-deploy snapshot. New PowerShell script (tagged
   `# CERTCTL_SNAPSHOT`) runs Get-ChildItem over the target store,
   captures every thumbprint, and for each cert with the same
   Subject as the new one calls Export-PfxCertificate to a tempdir
   using a transient snapshotExportPassword (32-byte random,
   distinct from the import PFX password). Output parsed into a
   snapshotState{Entries: []{Thumbprint, PfxPath}, AllThumbprints,
   TempDir, ExportPassword}. The new cert's Subject is parsed from
   request.CertPEM via certutil.ParseCertificatePEM before any
   cert-store mutation; PEM-parse failure aborts the deploy
   cleanly.

2. On-import-failure rollback. When the import-script Execute
   returns error, run a rollback script (tagged
   `# CERTCTL_ROLLBACK`) that:
   - Test-Path on the new cert path; Remove-Item if present.
   - Import-PfxCertificate -FilePath <pfxPath> for each snapshot
     entry (restores prior state).
   - Remove-Item -Recurse on the snapshot tempdir.

3. Post-rollback verification. Re-read Get-ChildItem (tagged
   `# CERTCTL_VERIFY`); assert every original thumbprint is back.
   On mismatch, append a warning to the DeploymentResult message
   (rollback ran but final state is suspect — operator inspection
   recommended). Skipped when AllThumbprints is empty (first-time
   deploy).

4. Success-path tempdir cleanup. New script tagged
   `# CERTCTL_CLEANUP` runs after a successful import to remove
   the snapshot tempdir on a best-effort basis. Failure here is
   non-fatal (debug log only).

5. Helper extraction. rollbackImport(ctx, snapshot, newThumbprint)
   + verifyRollback(ctx, snapshot) + cleanupSnapshot(ctx, snapshot)
   + parseSnapshotOutput are private methods/functions on
   Connector for clean test seams. Each script emits a unique
   `# CERTCTL_*` PowerShell comment tag so test mocks can match
   scripts deterministically — the snapshot/rollback/verify/cleanup
   scripts all reference Cert:\<store> paths, so the comment tags
   are the only deterministic substring under randomized map
   iteration.

DeploymentResult shape on failure:
- import OK, rollback OK   → Success=false, "PowerShell import
                              failed; rolled back" (clean
                              recoverable failure).
- import FAIL, rollback OK → same.
- rollback FAIL            → operator-actionable wrapped error
                              containing both errors; metadata
                              flags manual_action_required=true
                              and surfaces import_error /
                              rollback_error verbatim.

Tests added to wincertstore_test.go:
- TestWinCertStore_ImportFails_RemovesNewCert_RestoresOldFromSnapshot
  — happy rollback path with one same-Subject cert in the
  snapshot. Asserts rollback script contains Remove-Item for the
  new thumbprint AND Import-PfxCertificate referencing the
  snapshotted PFX path.
- TestWinCertStore_ImportFails_NoExistingSameSubject_RemovesNewCertOnly
  — snapshot has THUMB: lines but no SNAPSHOT: entries; rollback
  removes the new cert but does NOT call Import-PfxCertificate.
- TestWinCertStore_FriendlyNameFails_NewCertRemoved_OldCertsRestored
  — variant where the import script's failure originates from
  Set-ItemProperty FriendlyName; same rollback path. Asserts
  metadata.import_error preserves the FriendlyName-related
  PowerShell output for operator visibility.
- TestWinCertStore_ImportFails_RollbackAlsoFails_OperatorActionable
  — wrapped-error escalation. Asserts the error mentions both
  "PowerShell import failed" and "rollback also failed", and
  metadata flags manual_action_required=true.

Three existing tests (Success, ImportFailed, WithFriendlyName,
WithRemoveExpired) updated to match the new contract: success
path runs 3 PowerShell scripts (snapshot + import + cleanup),
import-failure path runs 4 (snapshot + import + rollback + verify),
and the import script lives at mock.scripts[1] not [0].

PowerShell injection note: the new cert's Subject DN is embedded
in the snapshot script as a single-quoted literal. Subject DNs can
contain apostrophes (e.g. CN=O'Reilly), so escapePowerShellSingleQuoted
doubles them per the PowerShell single-quoted-literal escape rule.
The export password and thumbprints come from
certutil.GenerateRandomPassword (alphanumeric only) and the cert's
SHA-1 thumbprint hex (alphanumeric); no escaping needed for those.

docs/deployment-atomicity.md L93 unchanged from today's text —
Bundle 1 doc-realignment hasn't shipped, so the "Get-ChildItem
snapshot for rollback" line was never softened. Post-Bundle-7 the
claim is honest (was aspirational pre-fix).

Verified locally (sandbox lacks staticcheck install due to disk
pressure; CI runs the full lint gate):
- gofmt -l ./internal/connector/target/wincertstore/  clean
- go vet ./internal/connector/target/wincertstore/  clean
- go build ./cmd/agent/...  clean
- go test -race -count=1 ./internal/connector/target/wincertstore/
  green

Audit reference: cowork/deployment-target-audit-2026-05-02/RESULTS.md
Bundle 7.
2026-05-02 18:13:40 +00:00
..