A 4-lens adversarial security review of the Phase 2 applier raised 19 issues
and confirmed 17 after per-finding verification. All are trust-boundary (they
require the signing key), but several break the explicit "no code-exec, always
reversible, nothing-silent" contract, so all 17 are fixed:
Trust path — fail CLOSED, never misreport:
- lpFetchIndex now surfaces the real signature state (LP_INDEX_SIGSTATE);
artifactApply REFUSES to mutate unless the index is actually verified, and
_artifactFetchPayload refuses an unsigned payload. The read path still
tolerates dev/unsigned but now says "UNSIGNED" instead of "Signed + verified".
- valid_until and index_serial are now MANDATORY + numeric in lpFetchIndex
(missing = refuse) — closes the anti-withholding / anti-rollback fail-opens.
Injection / code-exec (defense in depth even for a signed payload):
- runFileWrite rootless branch no longer builds a `bash -c` shell string with the
destination interpolated — it uses the argv form (like runFileOp), so a path
with a quote can't inject a command as the install user. (shared-helper fix)
- op paths must match a safe-filename charset (no quotes/$/backtick/;/newline);
set-config-key values and set-compose-image refs are charset-guarded too.
- content_b64 is validated as real base64 at precheck.
Reversibility / honest failure:
- dockerComposeUp now returns the real compose exit status (it always returned 0,
so the updater's rollback gate AND the apply's start-failure detection were
fail-open). (shared-helper fix)
- set-config-key undo captures the WHOLE config file (lossless) instead of a
lossy re-parsed scalar; edit-only (rejects an absent key).
- _artifactReplayUndoFile returns non-zero if any inverse op fails; auto-rollback
and revert now record "rollback-incomplete"/"revert-incomplete" + isError
instead of falsely claiming success, and revert keeps the record for retry.
- applied-record write failure is checked — apply rolls back rather than leave an
un-revertable change. System-scope regen failure is no longer swallowed.
- Writes are path-aware (configs/ -> runInstallWrite, container tree ->
runFileWrite) so system-scope hotfixes write/restore correctly.
- Checked lazy-sourcing surfaces a clear error instead of a bare exit 127.
Unit-tested 35/35 (adds: command-sub value rejection, bad image-ref, invalid
base64, quote/metachar path-injection rejection, replay-failure reporting).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: librelad <librelad@digitalangels.vip>
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