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.
97 lines
3.2 KiB
Go
97 lines
3.2 KiB
Go
package redis
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import (
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"context"
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"github.com/redis/go-redis/v9/internal/otel"
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)
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type PubSubCmdable interface {
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Publish(ctx context.Context, channel string, message interface{}) *IntCmd
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SPublish(ctx context.Context, channel string, message interface{}) *IntCmd
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PubSubChannels(ctx context.Context, pattern string) *StringSliceCmd
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PubSubNumSub(ctx context.Context, channels ...string) *MapStringIntCmd
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PubSubNumPat(ctx context.Context) *IntCmd
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PubSubShardChannels(ctx context.Context, pattern string) *StringSliceCmd
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PubSubShardNumSub(ctx context.Context, channels ...string) *MapStringIntCmd
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}
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// Publish posts the message to the channel.
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func (c cmdable) Publish(ctx context.Context, channel string, message interface{}) *IntCmd {
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cmd := NewIntCmd(ctx, "publish", channel, message)
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_ = c(ctx, cmd)
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// Record PubSub message sent (if command succeeded). Gated on the result
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// being readable WITHOUT blocking: on the deferred autopipeline face the
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// call above only enqueues, so reading the outcome here would await the
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// batch and turn a fire-and-forget publish into a blocking call — i.e.
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// enabling telemetry would change the async call shape (review finding by
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// codex on #3942). The metric is therefore skipped for a submission that
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// has not executed yet; recording it from the execution path instead is a
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// follow-up in the OTel wiring, not something the command wrapper can do.
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if otel.Enabled() && cmd.resultReady() && cmd.rawErr() == nil {
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otel.RecordPubSubMessage(ctx, nil, "sent", channel, false)
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}
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return cmd
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}
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func (c cmdable) SPublish(ctx context.Context, channel string, message interface{}) *IntCmd {
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cmd := NewIntCmd(ctx, "spublish", channel, message)
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_ = c(ctx, cmd)
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// Record PubSub message sent (if command succeeded). See Publish for why
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// this is gated on the result being readable without blocking.
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if otel.Enabled() && cmd.resultReady() && cmd.rawErr() == nil {
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otel.RecordPubSubMessage(ctx, nil, "sent", channel, true)
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}
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return cmd
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}
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func (c cmdable) PubSubChannels(ctx context.Context, pattern string) *StringSliceCmd {
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args := []interface{}{"pubsub", "channels"}
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if pattern != "*" {
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args = append(args, pattern)
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}
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cmd := NewStringSliceCmd(ctx, args...)
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_ = c(ctx, cmd)
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return cmd
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}
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func (c cmdable) PubSubNumSub(ctx context.Context, channels ...string) *MapStringIntCmd {
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args := make([]interface{}, 2+len(channels))
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args[0] = "pubsub"
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args[1] = "numsub"
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for i, channel := range channels {
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args[2+i] = channel
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}
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cmd := NewMapStringIntCmd(ctx, args...)
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_ = c(ctx, cmd)
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return cmd
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}
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func (c cmdable) PubSubShardChannels(ctx context.Context, pattern string) *StringSliceCmd {
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args := []interface{}{"pubsub", "shardchannels"}
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if pattern != "*" {
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args = append(args, pattern)
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}
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cmd := NewStringSliceCmd(ctx, args...)
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_ = c(ctx, cmd)
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return cmd
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}
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func (c cmdable) PubSubShardNumSub(ctx context.Context, channels ...string) *MapStringIntCmd {
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args := make([]interface{}, 2+len(channels))
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args[0] = "pubsub"
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args[1] = "shardnumsub"
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for i, channel := range channels {
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args[2+i] = channel
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}
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cmd := NewMapStringIntCmd(ctx, args...)
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_ = c(ctx, cmd)
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return cmd
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}
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func (c cmdable) PubSubNumPat(ctx context.Context) *IntCmd {
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cmd := NewIntCmd(ctx, "pubsub", "numpat")
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_ = c(ctx, cmd)
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return cmd
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}
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