hush/vendor/github.com/redis/go-redis/v9/hyperloglog_commands.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

43 lines
1.0 KiB
Go

package redis
import "context"
type HyperLogLogCmdable interface {
PFAdd(ctx context.Context, key string, els ...interface{}) *IntCmd
PFCount(ctx context.Context, keys ...string) *IntCmd
PFMerge(ctx context.Context, dest string, keys ...string) *StatusCmd
}
func (c cmdable) PFAdd(ctx context.Context, key string, els ...interface{}) *IntCmd {
args := make([]interface{}, 2, 2+len(els))
args[0] = "pfadd"
args[1] = key
args = appendArgs(args, els)
cmd := NewIntCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) PFCount(ctx context.Context, keys ...string) *IntCmd {
args := make([]interface{}, 1+len(keys))
args[0] = "pfcount"
for i, key := range keys {
args[1+i] = key
}
cmd := NewIntCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) PFMerge(ctx context.Context, dest string, keys ...string) *StatusCmd {
args := make([]interface{}, 2+len(keys))
args[0] = "pfmerge"
args[1] = dest
for i, key := range keys {
args[2+i] = key
}
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}