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.
99 lines
3.2 KiB
Go
99 lines
3.2 KiB
Go
// Copyright The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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import (
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"bufio"
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"bytes"
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"fmt"
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"strconv"
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"strings"
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"github.com/prometheus/procfs/internal/util"
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)
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// CgroupSummary models one line from /proc/cgroups.
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// This file contains information about the controllers that are compiled into the kernel.
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//
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// Also see http://man7.org/linux/man-pages/man7/cgroups.7.html
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type CgroupSummary struct {
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// The name of the controller. controller is also known as subsystem.
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SubsysName string
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// The unique ID of the cgroup hierarchy on which this controller is mounted.
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Hierarchy int
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// The number of control groups in this hierarchy using this controller.
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Cgroups int
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// This field contains the value 1 if this controller is enabled, or 0 if it has been disabled
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Enabled int
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}
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// parseCgroupSummary parses each line of the /proc/cgroup file
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// Line format is `subsys_name hierarchy num_cgroups enabled`.
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func parseCgroupSummaryString(cgroupSummaryStr string) (*CgroupSummary, error) {
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var err error
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fields := strings.Fields(cgroupSummaryStr)
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// require at least 4 fields
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if len(fields) < 4 {
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return nil, fmt.Errorf("%w: 4+ fields required, found %d fields in cgroup info string: %s", ErrFileParse, len(fields), cgroupSummaryStr)
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}
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CgroupSummary := &CgroupSummary{
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SubsysName: fields[0],
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}
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CgroupSummary.Hierarchy, err = strconv.Atoi(fields[1])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse hierarchy ID from %q", ErrFileParse, fields[1])
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}
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CgroupSummary.Cgroups, err = strconv.Atoi(fields[2])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse Cgroup Num from %q", ErrFileParse, fields[2])
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}
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CgroupSummary.Enabled, err = strconv.Atoi(fields[3])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse Enabled from %q", ErrFileParse, fields[3])
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}
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return CgroupSummary, nil
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}
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// parseCgroupSummary reads each line of the /proc/cgroup file.
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func parseCgroupSummary(data []byte) ([]CgroupSummary, error) {
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var CgroupSummarys []CgroupSummary
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scanner := bufio.NewScanner(bytes.NewReader(data))
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for scanner.Scan() {
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CgroupSummaryString := scanner.Text()
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// ignore comment lines
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if strings.HasPrefix(CgroupSummaryString, "#") {
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continue
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}
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CgroupSummary, err := parseCgroupSummaryString(CgroupSummaryString)
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if err != nil {
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return nil, err
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}
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CgroupSummarys = append(CgroupSummarys, *CgroupSummary)
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}
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err := scanner.Err()
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return CgroupSummarys, err
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}
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// CgroupSummarys returns information about current /proc/cgroups.
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func (fs FS) CgroupSummarys() ([]CgroupSummary, error) {
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data, err := util.ReadFileNoStat(fs.proc.Path("cgroups"))
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if err != nil {
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return nil, err
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}
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return parseCgroupSummary(data)
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}
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