hush/vendor/github.com/prometheus/common/model/silence.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

108 lines
2.8 KiB
Go

// Copyright 2015 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package model
import (
"encoding/json"
"errors"
"fmt"
"regexp"
"time"
)
// Matcher describes a matches the value of a given label.
type Matcher struct {
Name LabelName `json:"name"`
Value string `json:"value"`
IsRegex bool `json:"isRegex"`
}
func (m *Matcher) UnmarshalJSON(b []byte) error {
type plain Matcher
if err := json.Unmarshal(b, (*plain)(m)); err != nil {
return err
}
if len(m.Name) == 0 {
return errors.New("label name in matcher must not be empty")
}
if m.IsRegex {
if _, err := regexp.Compile(m.Value); err != nil {
return err
}
}
return nil
}
// Validate returns true iff all fields of the matcher have valid values.
func (m *Matcher) Validate() error {
if !m.Name.IsValid() {
return fmt.Errorf("invalid name %q", m.Name)
}
if m.IsRegex {
if _, err := regexp.Compile(m.Value); err != nil {
return fmt.Errorf("invalid regular expression %q", m.Value)
}
} else if !LabelValue(m.Value).IsValid() || len(m.Value) == 0 {
return fmt.Errorf("invalid value %q", m.Value)
}
return nil
}
// Silence defines the representation of a silence definition in the Prometheus
// eco-system.
type Silence struct {
ID uint64 `json:"id,omitempty"`
Matchers []*Matcher `json:"matchers"`
StartsAt time.Time `json:"startsAt"`
EndsAt time.Time `json:"endsAt"`
CreatedAt time.Time `json:"createdAt,omitempty"`
CreatedBy string `json:"createdBy"`
Comment string `json:"comment,omitempty"`
}
// Validate returns true iff all fields of the silence have valid values.
func (s *Silence) Validate() error {
if len(s.Matchers) == 0 {
return errors.New("at least one matcher required")
}
for _, m := range s.Matchers {
if err := m.Validate(); err != nil {
return fmt.Errorf("invalid matcher: %w", err)
}
}
if s.StartsAt.IsZero() {
return errors.New("start time missing")
}
if s.EndsAt.IsZero() {
return errors.New("end time missing")
}
if s.EndsAt.Before(s.StartsAt) {
return errors.New("start time must be before end time")
}
if s.CreatedBy == "" {
return errors.New("creator information missing")
}
if s.Comment == "" {
return errors.New("comment missing")
}
if s.CreatedAt.IsZero() {
return errors.New("creation timestamp missing")
}
return nil
}