Two interlocking pieces shipped together:
1. Strict Ed25519 signature verification on URL-fetched apps artifacts.
Every URL the apps cascade resolves must publish a corresponding
<url>.sig (raw 64-byte Ed25519 signature). The fetcher rejects on
any failure (sig 404, transport error, wrong key, tampered body)
and the resolver falls back to the embedded copy.
The trusted public key is OPERATOR-CONFIGURED via --apps-pubkey /
ZDDC_APPS_PUBKEY (PEM file path). No baked-in default — same posture
as TLS certificates. Operators using zddc.varasys.io's canonical
channels download pubkey.pem from there and configure the local
path. Operators with their own signing infrastructure pass their
own public key.
Build pipeline (./build) gains sign_release_artifacts: walks
dist/release-output/ after promote and produces an Ed25519 .sig
alongside every real file. ZDDC_SIGNING_KEY=~/.config/zddc-signing/
key.pem (mode 0600). Symlinks skip — the .sig at the symlink
target is what counts.
Test coverage: parse-PEM round-trip, malformed/wrong-type PEM
rejection, valid-signature accept, tampered-body reject, wrong-key
reject, malformed-signature reject, end-to-end fetch+sign+verify,
fetch-rejects-tampered, fetch-rejects-missing-sig, fetch-rejects-
wrong-key. Existing fetch tests updated to use signed-fixture
helpers.
2. Dev Helm chart mounts production data READ-ONLY and layers an
OverlayFS writable scratch on top. Prod data is the lowerdir;
dev's writes (form submissions, archive index state, .zddc edits)
land in upperdir; main container sees the merged read-write view
at $ZDDC_ROOT. Setup runs in a privileged init container; main
container runs unprivileged. Solves the dev-replica-on-shared-
dataset problem at the filesystem layer with no zddc-server code
change.
Docs: env-var tables in zddc/README.md and AGENTS.md gain a
ZDDC_APPS_PUBKEY row. The Federal-readiness gap analysis "Code-signed
apps: URL fetches" subsection is rewritten as "what's currently in
place" instead of "what would need to be added," with a forward
pointer to per-entry signed_by: (multi-key) and Sigstore as the
federally-acceptable evolution.
The website "Verify your downloads" section + the embedded pubkey
gone — but the website needs separate updates landing in zddc-website
to publish pubkey.pem and add the verify section. Pending in that
repo's commit.
Production binary unchanged at 13.1 MB. All 11 Go test packages green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds internal/apps/ package serving the five tool HTMLs at virtual paths
based on the surrounding folder name convention:
archive every directory (multi-project, project, archive, vendor)
classifier any Incoming/Working/Staging directory and subtree
mdedit any Working directory and subtree
transmittal any Staging directory and subtree
landing only at deployment root
The current-stable build of every tool is //go:embed'd into the binary
at compile time — that's the default with zero config. Operators
override per-directory via .zddc apps: entries; closer-to-leaf wins.
Spec syntax (in any apps: value):
stable / beta / alpha / :stable channel
v0.0.4 / v0.0 / v0 / :v0.0.4 version
https://my-mirror/releases URL prefix only
https://my-mirror/releases:beta URL prefix + channel
https://my-fork/archive.html terminal full URL
./local.html / /abs/path.html terminal local path
The special apps.default key provides a baseline URL prefix and channel
inherited by any app not overridden per-name. Per-axis cascade: a deeper
.zddc can override the URL, the channel, or both.
Cascade walks root→leaf; default applies first at each level, then the
per-app entry. Terminal sources (paths and full .html URLs) short-circuit
composition; deeper non-terminal entries override parent terminals.
URL sources fetch once on first request and cache forever in
<ZDDC_ROOT>/_app/<host>/<path> — different upstreams with the same
filename stay distinct. No background refresh, no SHA-256 verification:
operators delete the cache file to force a refetch. Concurrent misses
for the same source dedupe via a 30-line hand-rolled singleflight.
Per-request override: any user can append ?v=<spec> to a tool URL
(e.g. ?v=beta, ?v=v0.0.4, ?v=:alpha, ?v=https://mirror/releases:beta)
to ask for a different build for one request. Security: ?v= serves
ONLY versions already in the cache (cache miss returns 404; path
sources are rejected outright with 400). Users cannot trigger
arbitrary upstream fetches via crafted URLs.
Failed URL fetches (network down, 5xx) fall back to embedded with a
one-time WARN log. The X-ZDDC-Source response header reports what
served: fetch:URL / cache:URL / path:/abs / embedded:<app>@<build>.
Wire-in (cmd/zddc-server/main.go): dispatch routes <dir>/<app>.html
through apps.MatchAppHTML + AppAvailableAt + apps.Server.Serve when
no real file exists. Direct URL access to /_app/... is blocked at
the dispatch layer — cached files must go through the apps resolver
so they get correct Content-Type and ACL gating.
Schema (internal/zddc/file.go): ZddcFile gains Apps map[string]string
for cascade overrides. Validator (internal/zddc/validate.go) accepts
the special "default" key alongside the five canonical app names and
all spec forms.
Removes ZDDC_APPS_* env vars (no admin UI, no refresh interval, no
upstream allow-list — the simpler model has fewer knobs).
40+ unit tests across the new package: parser shapes, cascade
resolution with default+per-app interactions, terminal short-circuit
semantics, ?v= cache-only enforcement, embedded fallback, atomic
cache writes, singleflight dedup. Plus end-to-end dispatch tests in
cmd/zddc-server/main_test.go.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
