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.
77 lines
2.2 KiB
Go
77 lines
2.2 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
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package unix
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import "time"
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// TimespecToNsec returns the time stored in ts as nanoseconds.
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func TimespecToNsec(ts Timespec) int64 { return ts.Nano() }
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// NsecToTimespec converts a number of nanoseconds into a Timespec.
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func NsecToTimespec(nsec int64) Timespec {
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sec := nsec / 1e9
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nsec = nsec % 1e9
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if nsec < 0 {
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nsec += 1e9
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sec--
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}
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return setTimespec(sec, nsec)
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}
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// TimeToTimespec converts t into a Timespec.
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// On some 32-bit systems the range of valid Timespec values are smaller
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// than that of time.Time values. So if t is out of the valid range of
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// Timespec, it returns a zero Timespec and ERANGE.
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func TimeToTimespec(t time.Time) (Timespec, error) {
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sec := t.Unix()
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nsec := int64(t.Nanosecond())
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ts := setTimespec(sec, nsec)
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// Currently all targets have either int32 or int64 for Timespec.Sec.
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// If there were a new target with floating point type for it, we have
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// to consider the rounding error.
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if int64(ts.Sec) != sec {
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return Timespec{}, ERANGE
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}
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return ts, nil
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}
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// TimevalToNsec returns the time stored in tv as nanoseconds.
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func TimevalToNsec(tv Timeval) int64 { return tv.Nano() }
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// NsecToTimeval converts a number of nanoseconds into a Timeval.
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func NsecToTimeval(nsec int64) Timeval {
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nsec += 999 // round up to microsecond
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usec := nsec % 1e9 / 1e3
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sec := nsec / 1e9
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if usec < 0 {
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usec += 1e6
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sec--
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}
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return setTimeval(sec, usec)
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}
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// Unix returns the time stored in ts as seconds plus nanoseconds.
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func (ts *Timespec) Unix() (sec int64, nsec int64) {
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return int64(ts.Sec), int64(ts.Nsec)
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}
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// Unix returns the time stored in tv as seconds plus nanoseconds.
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func (tv *Timeval) Unix() (sec int64, nsec int64) {
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return int64(tv.Sec), int64(tv.Usec) * 1000
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}
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// Nano returns the time stored in ts as nanoseconds.
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func (ts *Timespec) Nano() int64 {
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return int64(ts.Sec)*1e9 + int64(ts.Nsec)
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}
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// Nano returns the time stored in tv as nanoseconds.
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func (tv *Timeval) Nano() int64 {
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return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000
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}
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