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.
110 lines
2.3 KiB
Go
110 lines
2.3 KiB
Go
package redis
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import (
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"context"
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"sync"
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"sync/atomic"
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)
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func (c *ClusterClient) DBSize(ctx context.Context) *IntCmd {
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cmd := NewIntCmd(ctx, "dbsize")
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_ = c.withProcessHook(ctx, cmd, func(ctx context.Context, _ Cmder) error {
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var size atomic.Int64
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err := c.ForEachMaster(ctx, func(ctx context.Context, master *Client) error {
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n, err := master.DBSize(ctx).Result()
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if err != nil {
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return err
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}
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size.Add(n)
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return nil
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})
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if err != nil {
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cmd.SetErr(err)
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} else {
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cmd.val = size.Load()
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}
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return nil
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})
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return cmd
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}
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func (c *ClusterClient) ScriptLoad(ctx context.Context, script string) *StringCmd {
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cmd := NewStringCmd(ctx, "script", "load", script)
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_ = c.withProcessHook(ctx, cmd, func(ctx context.Context, _ Cmder) error {
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var mu sync.Mutex
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err := c.ForEachShard(ctx, func(ctx context.Context, shard *Client) error {
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val, err := shard.ScriptLoad(ctx, script).Result()
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if err != nil {
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return err
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}
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mu.Lock()
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if cmd.Val() == "" {
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cmd.val = val
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}
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mu.Unlock()
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return nil
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})
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if err != nil {
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cmd.SetErr(err)
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}
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return nil
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})
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return cmd
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}
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func (c *ClusterClient) ScriptFlush(ctx context.Context) *StatusCmd {
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cmd := NewStatusCmd(ctx, "script", "flush")
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_ = c.withProcessHook(ctx, cmd, func(ctx context.Context, _ Cmder) error {
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err := c.ForEachShard(ctx, func(ctx context.Context, shard *Client) error {
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return shard.ScriptFlush(ctx).Err()
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})
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if err != nil {
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cmd.SetErr(err)
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}
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return nil
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})
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return cmd
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}
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func (c *ClusterClient) ScriptExists(ctx context.Context, hashes ...string) *BoolSliceCmd {
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args := make([]interface{}, 2+len(hashes))
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args[0] = "script"
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args[1] = "exists"
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for i, hash := range hashes {
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args[2+i] = hash
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}
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cmd := NewBoolSliceCmd(ctx, args...)
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result := make([]bool, len(hashes))
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for i := range result {
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result[i] = true
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}
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_ = c.withProcessHook(ctx, cmd, func(ctx context.Context, _ Cmder) error {
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var mu sync.Mutex
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err := c.ForEachShard(ctx, func(ctx context.Context, shard *Client) error {
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val, err := shard.ScriptExists(ctx, hashes...).Result()
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if err != nil {
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return err
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}
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mu.Lock()
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for i, v := range val {
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result[i] = result[i] && v
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}
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mu.Unlock()
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return nil
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})
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if err != nil {
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cmd.SetErr(err)
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} else {
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cmd.val = result
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}
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return nil
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})
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return cmd
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}
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