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.
122 lines
3.0 KiB
Go
122 lines
3.0 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"
|
|
"errors"
|
|
"os"
|
|
"regexp"
|
|
"strconv"
|
|
)
|
|
|
|
var (
|
|
cpuLineRE = regexp.MustCompile(`cpu(\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+)`)
|
|
procLineRE = regexp.MustCompile(`(\d+) (\d+) (\d+)`)
|
|
)
|
|
|
|
// Schedstat contains scheduler statistics from /proc/schedstat
|
|
//
|
|
// See
|
|
// https://www.kernel.org/doc/Documentation/scheduler/sched-stats.txt
|
|
// for a detailed description of what these numbers mean.
|
|
//
|
|
// Note the current kernel documentation claims some of the time units are in
|
|
// jiffies when they are actually in nanoseconds since 2.6.23 with the
|
|
// introduction of CFS. A fix to the documentation is pending. See
|
|
// https://lore.kernel.org/patchwork/project/lkml/list/?series=403473
|
|
type Schedstat struct {
|
|
CPUs []*SchedstatCPU
|
|
}
|
|
|
|
// SchedstatCPU contains the values from one "cpu<N>" line.
|
|
type SchedstatCPU struct {
|
|
CPUNum string
|
|
|
|
RunningNanoseconds uint64
|
|
WaitingNanoseconds uint64
|
|
RunTimeslices uint64
|
|
}
|
|
|
|
// ProcSchedstat contains the values from `/proc/<pid>/schedstat`.
|
|
type ProcSchedstat struct {
|
|
RunningNanoseconds uint64
|
|
WaitingNanoseconds uint64
|
|
RunTimeslices uint64
|
|
}
|
|
|
|
// Schedstat reads data from `/proc/schedstat`.
|
|
func (fs FS) Schedstat() (*Schedstat, error) {
|
|
file, err := os.Open(fs.proc.Path("schedstat"))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer file.Close()
|
|
|
|
stats := &Schedstat{}
|
|
scanner := bufio.NewScanner(file)
|
|
|
|
for scanner.Scan() {
|
|
match := cpuLineRE.FindStringSubmatch(scanner.Text())
|
|
if match != nil {
|
|
cpu := &SchedstatCPU{}
|
|
cpu.CPUNum = match[1]
|
|
|
|
cpu.RunningNanoseconds, err = strconv.ParseUint(match[8], 10, 64)
|
|
if err != nil {
|
|
continue
|
|
}
|
|
|
|
cpu.WaitingNanoseconds, err = strconv.ParseUint(match[9], 10, 64)
|
|
if err != nil {
|
|
continue
|
|
}
|
|
|
|
cpu.RunTimeslices, err = strconv.ParseUint(match[10], 10, 64)
|
|
if err != nil {
|
|
continue
|
|
}
|
|
|
|
stats.CPUs = append(stats.CPUs, cpu)
|
|
}
|
|
}
|
|
|
|
return stats, nil
|
|
}
|
|
|
|
func parseProcSchedstat(contents string) (ProcSchedstat, error) {
|
|
var (
|
|
stats ProcSchedstat
|
|
err error
|
|
)
|
|
match := procLineRE.FindStringSubmatch(contents)
|
|
|
|
if match != nil {
|
|
stats.RunningNanoseconds, err = strconv.ParseUint(match[1], 10, 64)
|
|
if err != nil {
|
|
return stats, err
|
|
}
|
|
|
|
stats.WaitingNanoseconds, err = strconv.ParseUint(match[2], 10, 64)
|
|
if err != nil {
|
|
return stats, err
|
|
}
|
|
|
|
stats.RunTimeslices, err = strconv.ParseUint(match[3], 10, 64)
|
|
return stats, err
|
|
}
|
|
|
|
return stats, errors.New("could not parse schedstat")
|
|
}
|