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.
62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
package push
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import (
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"sync"
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)
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// Registry manages push notification handlers
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type Registry struct {
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mu sync.RWMutex
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handlers map[string]NotificationHandler
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protected map[string]bool
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}
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// NewRegistry creates a new push notification registry
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func NewRegistry() *Registry {
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return &Registry{
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handlers: make(map[string]NotificationHandler),
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protected: make(map[string]bool),
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}
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}
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// RegisterHandler registers a handler for a specific push notification name
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func (r *Registry) RegisterHandler(pushNotificationName string, handler NotificationHandler, protected bool) error {
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if handler == nil {
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return ErrHandlerNil
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}
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r.mu.Lock()
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defer r.mu.Unlock()
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// Check if handler already exists
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if _, exists := r.protected[pushNotificationName]; exists {
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return ErrHandlerExists(pushNotificationName)
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}
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r.handlers[pushNotificationName] = handler
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r.protected[pushNotificationName] = protected
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return nil
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}
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// GetHandler returns the handler for a specific push notification name
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func (r *Registry) GetHandler(pushNotificationName string) NotificationHandler {
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r.mu.RLock()
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defer r.mu.RUnlock()
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return r.handlers[pushNotificationName]
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}
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// UnregisterHandler removes a handler for a specific push notification name
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func (r *Registry) UnregisterHandler(pushNotificationName string) error {
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r.mu.Lock()
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defer r.mu.Unlock()
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// Check if handler is protected
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if protected, exists := r.protected[pushNotificationName]; exists && protected {
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return ErrProtectedHandler(pushNotificationName)
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}
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delete(r.handlers, pushNotificationName)
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delete(r.protected, pushNotificationName)
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return nil
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}
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