hush/vendor/google.golang.org/protobuf/proto/equal.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

67 lines
2.2 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package proto
import (
"reflect"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/runtime/protoiface"
)
// Equal reports whether two messages are equal,
// by recursively comparing the fields of the message.
//
// - Bytes fields are equal if they contain identical bytes.
// Empty bytes (regardless of nil-ness) are considered equal.
//
// - Floating-point fields are equal if they contain the same value.
// Unlike the == operator, a NaN is equal to another NaN.
//
// - Other scalar fields are equal if they contain the same value.
//
// - Message fields are equal if they have
// the same set of populated known and extension field values, and
// the same set of unknown fields values.
//
// - Lists are equal if they are the same length and
// each corresponding element is equal.
//
// - Maps are equal if they have the same set of keys and
// the corresponding value for each key is equal.
//
// An invalid message is not equal to a valid message.
// An invalid message is only equal to another invalid message of the
// same type. An invalid message often corresponds to a nil pointer
// of the concrete message type. For example, (*pb.M)(nil) is not equal
// to &pb.M{}.
// If two valid messages marshal to the same bytes under deterministic
// serialization, then Equal is guaranteed to report true.
func Equal(x, y Message) bool {
if x == nil || y == nil {
return x == nil && y == nil
}
if reflect.TypeOf(x).Kind() == reflect.Ptr && x == y {
// Avoid an expensive comparison if both inputs are identical pointers.
return true
}
mx := x.ProtoReflect()
my := y.ProtoReflect()
if mx.IsValid() != my.IsValid() {
return false
}
// Only one of the messages needs to implement the fast-path for it to work.
pmx := protoMethods(mx)
pmy := protoMethods(my)
if pmx != nil && pmy != nil && pmx.Equal != nil && pmy.Equal != nil {
return pmx.Equal(protoiface.EqualInput{MessageA: mx, MessageB: my}).Equal
}
vx := protoreflect.ValueOfMessage(mx)
vy := protoreflect.ValueOfMessage(my)
return vx.Equal(vy)
}