hush/vendor/github.com/redis/go-redis/v9/internal/util.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

138 lines
2.3 KiB
Go

package internal
import (
"context"
"math"
"net"
"strconv"
"strings"
"time"
"github.com/redis/go-redis/v9/internal/util"
)
// String representations of special float values.
// Values are lowercase for consistency with Redis RESP2 protocol responses.
const (
NaN = "nan" // Not a Number
Inf = "inf" // Positive infinity
NInf = "-inf" // Negative infinity
)
// FormatFloat formats a float64 to string, normalizing special values
// (NaN, Inf) to lowercase for consistency with Redis RESP2 protocol.
func FormatFloat(f float64) string {
switch {
case math.IsNaN(f):
return NaN
case math.IsInf(f, 1):
return Inf
case math.IsInf(f, -1):
return NInf
default:
return strconv.FormatFloat(f, 'f', -1, 64)
}
}
func Sleep(ctx context.Context, dur time.Duration) error {
t := time.NewTimer(dur)
defer t.Stop()
select {
case <-t.C:
return nil
case <-ctx.Done():
return ctx.Err()
}
}
func ToLower(s string) string {
if isLower(s) {
return s
}
b := make([]byte, len(s))
for i := range b {
c := s[i]
if c >= 'A' && c <= 'Z' {
c += 'a' - 'A'
}
b[i] = c
}
return util.BytesToString(b)
}
func isLower(s string) bool {
for i := 0; i < len(s); i++ {
c := s[i]
if c >= 'A' && c <= 'Z' {
return false
}
}
return true
}
func ReplaceSpaces(s string) string {
return strings.ReplaceAll(s, " ", "-")
}
func GetAddr(addr string) string {
ind := strings.LastIndexByte(addr, ':')
if ind == -1 {
return ""
}
if strings.IndexByte(addr, '.') != -1 {
return addr
}
if addr[0] == '[' {
return addr
}
return net.JoinHostPort(addr[:ind], addr[ind+1:])
}
func ToInteger(val interface{}) int {
switch v := val.(type) {
case int:
return v
case int64:
return int(v)
case string:
i, _ := strconv.Atoi(v)
return i
default:
return 0
}
}
func ToFloat(val interface{}) float64 {
switch v := val.(type) {
case float64:
return v
case string:
f, _ := strconv.ParseFloat(v, 64)
return f
default:
return 0.0
}
}
func ToString(val interface{}) string {
if str, ok := val.(string); ok {
return str
}
return ""
}
func ToStringSlice(val interface{}) []string {
if arr, ok := val.([]interface{}); ok {
result := make([]string, len(arr))
for i, v := range arr {
result[i] = ToString(v)
}
return result
}
return nil
}