hush/vendor/go.uber.org/atomic/duration.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

90 lines
2.7 KiB
Go

// @generated Code generated by gen-atomicwrapper.
// Copyright (c) 2020-2023 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package atomic
import (
"encoding/json"
"time"
)
// Duration is an atomic type-safe wrapper for time.Duration values.
type Duration struct {
_ nocmp // disallow non-atomic comparison
v Int64
}
var _zeroDuration time.Duration
// NewDuration creates a new Duration.
func NewDuration(val time.Duration) *Duration {
x := &Duration{}
if val != _zeroDuration {
x.Store(val)
}
return x
}
// Load atomically loads the wrapped time.Duration.
func (x *Duration) Load() time.Duration {
return time.Duration(x.v.Load())
}
// Store atomically stores the passed time.Duration.
func (x *Duration) Store(val time.Duration) {
x.v.Store(int64(val))
}
// CAS is an atomic compare-and-swap for time.Duration values.
//
// Deprecated: Use CompareAndSwap.
func (x *Duration) CAS(old, new time.Duration) (swapped bool) {
return x.CompareAndSwap(old, new)
}
// CompareAndSwap is an atomic compare-and-swap for time.Duration values.
func (x *Duration) CompareAndSwap(old, new time.Duration) (swapped bool) {
return x.v.CompareAndSwap(int64(old), int64(new))
}
// Swap atomically stores the given time.Duration and returns the old
// value.
func (x *Duration) Swap(val time.Duration) (old time.Duration) {
return time.Duration(x.v.Swap(int64(val)))
}
// MarshalJSON encodes the wrapped time.Duration into JSON.
func (x *Duration) MarshalJSON() ([]byte, error) {
return json.Marshal(x.Load())
}
// UnmarshalJSON decodes a time.Duration from JSON.
func (x *Duration) UnmarshalJSON(b []byte) error {
var v time.Duration
if err := json.Unmarshal(b, &v); err != nil {
return err
}
x.Store(v)
return nil
}