hush/vendor/github.com/redis/go-redis/v9/maintnotifications/hooks.go
jx12n 4d9a26498e hush: one-time secret links the server cannot read
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.
2026-09-03 00:08:38 -06:00

61 lines
2.1 KiB
Go

package maintnotifications
import (
"context"
"slices"
"github.com/redis/go-redis/v9/internal"
"github.com/redis/go-redis/v9/internal/maintnotifications/logs"
"github.com/redis/go-redis/v9/internal/pool"
"github.com/redis/go-redis/v9/push"
)
// LoggingHook is an example hook implementation that logs all notifications.
type LoggingHook struct {
LogLevel int // 0=Error, 1=Warn, 2=Info, 3=Debug
}
// PreHook logs the notification before processing and allows modification.
func (lh *LoggingHook) PreHook(ctx context.Context, notificationCtx push.NotificationHandlerContext, notificationType string, notification []interface{}) ([]interface{}, bool) {
if lh.LogLevel >= 2 { // Info level
// Log the notification type and content
connID := uint64(0)
if conn, ok := notificationCtx.Conn.(*pool.Conn); ok {
connID = conn.GetID()
}
seqID := int64(0)
if slices.Contains(maintenanceNotificationTypes, notificationType) {
// seqID is the second element in the notification array
if len(notification) > 1 {
if parsedSeqID, ok := notification[1].(int64); !ok {
seqID = 0
} else {
seqID = parsedSeqID
}
}
}
internal.Logger.Printf(ctx, logs.ProcessingNotification(connID, seqID, notificationType, notification))
}
return notification, true // Continue processing with unmodified notification
}
// PostHook logs the result after processing.
func (lh *LoggingHook) PostHook(ctx context.Context, notificationCtx push.NotificationHandlerContext, notificationType string, notification []interface{}, result error) {
connID := uint64(0)
if conn, ok := notificationCtx.Conn.(*pool.Conn); ok {
connID = conn.GetID()
}
if result != nil && lh.LogLevel >= 1 { // Warning level
internal.Logger.Printf(ctx, logs.ProcessingNotificationFailed(connID, notificationType, result, notification))
} else if lh.LogLevel >= 3 { // Debug level
internal.Logger.Printf(ctx, logs.ProcessingNotificationSucceeded(connID, notificationType))
}
}
// NewLoggingHook creates a new logging hook with the specified log level.
// Log levels: 0=Error, 1=Warn, 2=Info, 3=Debug
func NewLoggingHook(logLevel int) *LoggingHook {
return &LoggingHook{LogLevel: logLevel}
}