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.
92 lines
2.4 KiB
Go
92 lines
2.4 KiB
Go
// Copyright The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package util
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import (
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"strconv"
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)
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// TODO(mdlayher): util packages are an anti-pattern and this should be moved
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// somewhere else that is more focused in the future.
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// A ValueParser enables parsing a single string into a variety of data types
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// in a concise and safe way. The Err method must be invoked after invoking
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// any other methods to ensure a value was successfully parsed.
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type ValueParser struct {
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v string
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err error
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}
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// NewValueParser creates a ValueParser using the input string.
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func NewValueParser(v string) *ValueParser {
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return &ValueParser{v: v}
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}
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// Int interprets the underlying value as an int and returns that value.
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func (vp *ValueParser) Int() int { return int(vp.int64()) }
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// PInt64 interprets the underlying value as an int64 and returns a pointer to
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// that value.
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func (vp *ValueParser) PInt64() *int64 {
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if vp.err != nil {
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return nil
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}
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v := vp.int64()
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return &v
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}
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// int64 interprets the underlying value as an int64 and returns that value.
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// TODO: export if/when necessary.
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func (vp *ValueParser) int64() int64 {
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if vp.err != nil {
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return 0
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}
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// A base value of zero makes ParseInt infer the correct base using the
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// string's prefix, if any.
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const base = 0
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v, err := strconv.ParseInt(vp.v, base, 64)
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if err != nil {
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vp.err = err
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return 0
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}
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return v
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}
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// PUInt64 interprets the underlying value as an uint64 and returns a pointer to
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// that value.
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func (vp *ValueParser) PUInt64() *uint64 {
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if vp.err != nil {
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return nil
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}
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// A base value of zero makes ParseInt infer the correct base using the
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// string's prefix, if any.
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const base = 0
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v, err := strconv.ParseUint(vp.v, base, 64)
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if err != nil {
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vp.err = err
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return nil
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}
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return &v
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}
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// Err returns the last error, if any, encountered by the ValueParser.
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func (vp *ValueParser) Err() error {
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return vp.err
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}
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