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.
84 lines
2.2 KiB
Go
84 lines
2.2 KiB
Go
// Copyright The Prometheus Authors
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package procfs
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"io"
|
|
"os"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
// A BuddyInfo is the details parsed from /proc/buddyinfo.
|
|
// The data is comprised of an array of free fragments of each size.
|
|
// The sizes are 2^n*PAGE_SIZE, where n is the array index.
|
|
type BuddyInfo struct {
|
|
Node string
|
|
Zone string
|
|
Sizes []float64
|
|
}
|
|
|
|
// BuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
|
|
func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
|
|
file, err := os.Open(fs.proc.Path("buddyinfo"))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer file.Close()
|
|
|
|
return parseBuddyInfo(file)
|
|
}
|
|
|
|
func parseBuddyInfo(r io.Reader) ([]BuddyInfo, error) {
|
|
var (
|
|
buddyInfo = []BuddyInfo{}
|
|
scanner = bufio.NewScanner(r)
|
|
bucketCount = -1
|
|
)
|
|
|
|
for scanner.Scan() {
|
|
var err error
|
|
line := scanner.Text()
|
|
parts := strings.Fields(line)
|
|
|
|
if len(parts) < 4 {
|
|
return nil, fmt.Errorf("%w: Invalid number of fields, found: %v", ErrFileParse, parts)
|
|
}
|
|
|
|
node := strings.TrimSuffix(parts[1], ",")
|
|
zone := strings.TrimSuffix(parts[3], ",")
|
|
arraySize := len(parts[4:])
|
|
|
|
if bucketCount == -1 {
|
|
bucketCount = arraySize
|
|
} else if bucketCount != arraySize {
|
|
return nil, fmt.Errorf("%w: mismatch in number of buddyinfo buckets, previous count %d, new count %d", ErrFileParse, bucketCount, arraySize)
|
|
}
|
|
|
|
sizes := make([]float64, arraySize)
|
|
for i := range arraySize {
|
|
sizes[i], err = strconv.ParseFloat(parts[i+4], 64)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("%w: Invalid valid in buddyinfo: %f: %w", ErrFileParse, sizes[i], err)
|
|
}
|
|
}
|
|
|
|
buddyInfo = append(buddyInfo, BuddyInfo{node, zone, sizes})
|
|
}
|
|
|
|
return buddyInfo, scanner.Err()
|
|
}
|