4d9a26498e
Paste a secret, get a link, send it. The first person to open it and press
Reveal sees the secret; the link dies at that moment. The recipient needs a
browser and nothing else — no account, no client, no installed tooling.
The server cannot read what it stores. AES-256-GCM happens in the browser and
the key lives in the URL fragment, which browsers never transmit, so hushd
holds ciphertext and no key material. That is a property of where the key sits
rather than a promise about our conduct, which is why there is deliberately no
endpoint accepting a plaintext secret and no server-side-encryption fallback:
two guarantees behind one URL would be worse than one honest guarantee.
Three decisions carry the design:
* GET /s/{id} touches NO storage, not even to check existence. Slack, Teams,
WhatsApp, iMessage and Outlook Safe Links all fetch a URL before a human
sees it, so destroying on GET would destroy most secrets in transit and the
recipient's "already used" would be indistinguishable from interception.
Only POST /reveal consumes. Bot user-agent detection is an arms race;
removing the side effect from GET is not. Pinned by
TestGettingTheRevealPageNeverConsumesTheSecret.
* Destruction is one Redis GETDEL, which is atomic. GET-then-DEL has a window
where two simultaneous readers both win, and for a one-time secret that
window is the product. The store contract demands atomicity and the same
concurrency test runs against both implementations.
* Missing, already-revealed, expired and evicted are ONE indistinguishable
410. Separating them would confirm to a prober that a given link was real.
The secret id IS the capability, so secret.ID is a struct whose every
accidental path — %v, %s, String(), slog, json.Marshal — emits a redacted
handle or refuses, and the raw value needs an explicit Value(). The first
version tried to prevent leaks by implementing no String() at all; its own test
caught that Go's fmt prints unexported fields anyway, so forbidding the method
had removed the control rather than the leak.
Operationally: structured JSON on stdout in the fleet's wire format, which
Vector already collects with no annotation; six hush_* metrics on the chassis
registry with no id, IP or path in any label; five alert rules wired into
vmalert. The public Ingress enumerates /, /s/ and /api/ so /metrics, /healthz
and /readyz share the port but are unreachable from the internet — no
basic-auth middleware to maintain and get wrong.
Dependencies are vendored because go-chassis is private: the Woodpecker test
step and the in-cluster Kaniko build both run -mod=vendor with GOPROXY=off and
hold no git credential.
cmd/hush-mcp is a stdio MCP server doing the same client-side crypto locally,
so using hush from an agent preserves the same guarantee as using it from a
browser.
38 lines
1.1 KiB
Go
38 lines
1.1 KiB
Go
package chassis
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// Authorization middleware — the layer above authentication. RequireAuth proves
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// WHO; these prove WHAT they may do and WHICH tenant they act in. Apply after
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// RequireAuth on a route group.
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// RequireScope rejects callers lacking the given scope (scope dominance applies:
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// a held "x:*" satisfies "x:read"). 401 if unauthenticated, 403 if under-scoped.
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func RequireScope(scope string) Middleware {
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return func(next HandlerFunc) HandlerFunc {
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return func(c *Context) error {
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id, ok := c.Identity()
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if !ok {
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return Unauthorized("authentication required")
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}
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if !id.HasScope(scope) {
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return Forbidden("missing required scope: " + scope)
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}
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return next(c)
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}
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}
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}
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// RequireOrg enforces the multi-tenant invariant: the caller must have a resolved
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// active organization. Handlers behind it can rely on a non-empty Context.OrgID
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// and MUST filter every tenant query by it.
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func RequireOrg() Middleware {
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return func(next HandlerFunc) HandlerFunc {
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return func(c *Context) error {
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id, ok := c.Identity()
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if !ok || id.OrgID == "" {
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return Forbidden("no active organization")
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}
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return next(c)
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}
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}
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}
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