Authenticate /hook/*, and make every hook a command hook

/hook/record and /hook/approve accepted anything that reached the port. That is
not "loopback only": `tailscale serve` proxies tailnet traffic to 127.0.0.1, so
anyone who could reach the tunnel could forge timeline events and answer
approval prompts. Both endpoints now require a 32-byte secret from
$GLANCE_HOME/hook.secret (0600, created once, never rotated so nothing in
flight is 403'd mid-session), compared in constant time before the body is
read, as an x-glance-hook header or a ?k= parameter. Requests carrying
x-forwarded-* are refused outright: a local hook process never sends them and a
tunnelled caller always does. The check applies to /hook/* only, so the
dashboard is unaffected.

While wiring that up: the 13 passive `type: "http"` hooks could never have
worked. Grok Build's http runner rejects every scheme but https, then resolves
the host and blocks private/link-local/CGNAT addresses (validate_hook_url +
is_blocked_ip), so neither loopback-over-http nor *.ts.net (100.64/10) can be a
hook target - and it sends no header but Content-Type, so such a hook could not
authenticate anyway. They were failing validation silently on every event. All
of them are now command hooks running bin/glance-record.mjs, which costs a Node
start and can present the secret.

hooks.json is generated from hooks/hooks.template.json by scripts/gen-hooks.mjs
(npm run build, glance sync-hooks). It creates the secret, derives the approval
hook's timeout from approval.timeoutMs instead of hand-copying 125, and refuses
to write a hook that cannot fire: bad type, non-positive timeout, non-https
http URL, missing bin/ script, or a leftover placeholder. A template that
embeds the token makes the output 0600 with a warning.

Fail-open is unchanged: a missing, stale or rejected secret degrades to "no
telemetry", and glance-approve.mjs still allows on every error path. glance
status warns when the on-disk secret no longer matches the daemon's.

Validated with the e2e suite (190 checks, including no-token/wrong-token/
same-length-token 403s, ?k= acceptance, x-forwarded-* refusal, and the
recorder's fail-open paths) and a clean npm run build.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
iceBear67
2026-08-09 04:52:17 +00:00
co-authored by Claude Opus 5
parent b3b6bf3f70
commit 5eec1940be
15 changed files with 661 additions and 81 deletions
+50 -21
View File
@@ -46,7 +46,10 @@ npm install && npm run build
```
The build produces `dist/server` (the daemon) and `dist/web` (the dashboard). Both are required;
the daemon serves the dashboard itself.
the daemon serves the dashboard itself. It also generates `hooks/hooks.json` from
`hooks/hooks.template.json`, and creates `~/.grok/glance/hook.secret` (mode 0600) if it does not
exist yet — the shared secret the hook scripts authenticate with. Neither the secret nor anything
derived from it ends up in `hooks.json`.
Then register the directory with Grok Build. Plugins are installed from a marketplace catalog, so
for a local checkout the shortest path is a one-entry catalog. Create
@@ -144,12 +147,13 @@ Defaults worth knowing:
|---|---|---|---|
| Only wait when a phone is watching | on | yes | Otherwise a closed browser tab stalls the agent for 90s per tool call. |
| On timeout | allow | yes | Flip to *deny* if you would rather fail closed. |
| Timeout | 90s | no — edit `config.json` | The hook's own timeout is 125s; raising this past that would just make the hook give up first. |
| Timeout | 90s | no — edit `config.json` | The hook's own timeout is derived from this (`+35s` of slack) when `hooks.json` is generated, so re-run `sync-hooks` after changing it. |
| Risky-tool pattern | `^(Bash\|Write\|Edit\|MultiEdit\|NotebookEdit)$` | no — edit `config.json` | Shown on the phone but not editable: a typo'd regex would silently change what gets gated. |
**This is a convenience gate, not a security boundary.** Every failure path is fail-open: daemon
down, hook timeout, malformed response, port mismatch — the tool call proceeds. If you need calls
actually blocked, use Grok Build's own permission settings.
down, hook timeout, malformed response, port mismatch, a hook secret the daemon no longer
recognises — the tool call proceeds. If you need calls actually blocked, use Grok Build's own
permission settings.
## CLI
@@ -167,7 +171,7 @@ actually blocked, use Grok Build's own permission settings.
| `devices` | List enrolled devices |
| `revoke <id-prefix>` | Revoke a device |
| `approval <off\|risky\|all>` | Set the approval policy |
| `sync-hooks` | Rewrite hook URLs after changing the port |
| `sync-hooks` | Regenerate `hooks/hooks.json` from the template (after changing `config.json`) |
## Files and configuration
@@ -180,6 +184,7 @@ Everything lives in `~/.grok/glance` (mode 0700), or `$GLANCE_HOME` if you set i
| `auth-sessions.json` | Live dashboard sessions, stored as SHA-256 hashes of the cookie tokens |
| `secret.key` | 32-byte HMAC key used to sign session cookies |
| `admin.token` | Rotated every daemon start; authenticates the CLI |
| `hook.secret` | Shared secret the hook scripts present on `/hook/*`. Created once, mode 0600, never rotated — a rotation mid-session would 403 whatever was already in flight. Delete it and the daemon mints a new one on its next start; hooks then need that restart to agree again, which `glance status` will tell you about. |
| `events.jsonl` | Append-only event log, one JSON object per line, rotated at 5 MB |
| `daemon.log` | Daemon stdout/stderr |
@@ -192,8 +197,10 @@ instance without touching your real one:
| `GLANCE_PORT` | Port to listen on (and, for the CLI and hooks, to talk to) |
| `GLANCE_ORIGIN` | Public origin, as if set with `set-origin` — but not persisted |
To change the port, edit `config.json`, then run `node bin/glance sync-hooks` so the hook URLs in
`hooks/hooks.json` match. Restart the daemon afterwards.
The port is not baked into `hooks/hooks.json` the hook scripts read `config.json` themselves — so
changing it needs nothing but a daemon restart. Changing `approval.timeoutMs` does affect the
generated file: run `node bin/glance sync-hooks` afterwards so the approval hook's own timeout still
outlasts the wait.
## Security notes
@@ -202,13 +209,20 @@ its own. Three classes of caller:
| Path | Caller | Authentication |
|---|---|---|
| `/hook/record`, `/hook/approve` | Grok Build's hooks, from this machine | none — loopback only |
| `/hook/record`, `/hook/approve` | Grok Build's hooks, from this machine | shared secret from `hook.secret`, plus a refusal of any proxied request |
| `/api/*`, `/events` | the dashboard | passkey session cookie + CSRF header |
| `/local/*` | the `glance` CLI | rotating admin token from `admin.token` |
`/local/*` is token-gated rather than "is it from localhost", because `tailscale serve` proxies
remote traffic to `127.0.0.1` — the daemon cannot tell a local caller from a tunnelled one by
address alone.
None of the three trusts the source address, because `tailscale serve` proxies remote traffic to
`127.0.0.1` — the daemon cannot tell a local caller from a tunnelled one by address alone. Without
the hook secret, anyone who could reach the tunnel could forge timeline events and answer approval
prompts on your behalf; `/hook/*` compares the secret in constant time before it reads a body, and
additionally refuses any request carrying `x-forwarded-for` or `x-forwarded-proto`, which a local
hook process never sends and a tunnelled caller always does.
That refusal costs nothing, because no legitimate hook traffic comes through the tunnel: hooks are
local processes talking to loopback. It applies **only** to `/hook/*` — the dashboard arrives
through `tailscale serve` with those headers on every request and is unaffected.
**Session cookie** is `HttpOnly`, `SameSite=Strict`, HMAC-signed, and `Secure` whenever the request
arrived over https. Only a SHA-256 hash of the token is stored, compared in constant time. Sessions
@@ -256,21 +270,36 @@ stop working and must be enrolled again.
## Hook wiring
`hooks/hooks.json` subscribes to all 14 lifecycle events. Passive events use `type: "http"`: they
POST straight into the daemon with no process spawn, so they cost close to nothing per tool call
and quietly do nothing when the daemon is down.
`hooks/hooks.json` subscribes to all 14 lifecycle events, and **is generated** — from
`hooks/hooks.template.json` by `scripts/gen-hooks.mjs`, which runs as part of `npm run build` and on
`node bin/glance sync-hooks`. Edit the template, not the output.
Two exceptions:
Every entry is a `command` hook. That is not a style choice: an `http` hook cannot reach this daemon
by any route. Grok Build's http runner rejects every scheme but `https`, then **resolves the host**
and refuses the resolved address if it is private, link-local or CGNAT
(`xai-grok-hooks/src/runner/http.rs`, `validate_hook_url` + `is_blocked_ip`). Plain http on loopback
fails the scheme check; the tailnet fails the address check, because `*.ts.net` resolves into
`100.64/10` (and `fd7a::/48`, inside the blocked `fc00::/7`). On top of that the runner sends no
request header but `Content-Type`, with no configuration surface for one, so such a hook could not
authenticate itself even if it could connect. The generator refuses to emit an `http` handler whose
URL is not `https://`, because the alternative is what this plugin shipped for a while: 13 passive
hooks that failed validation silently on every event.
A command hook has none of those problems. It is a local process, so no URL is validated, nothing
traverses the tunnel, and it can present the shared secret — hook traffic goes straight to
`http://127.0.0.1:8791` and never leaves the machine. So each observed event runs
`bin/glance-record.mjs`, which costs a Node start (~40 ms) and POSTs one event. Two entries differ:
- `SessionStart` runs `bin/glance-up.mjs`, which is what boots the daemon.
- `PreToolUse` is wired **twice** — an `http` entry that records every call for the timeline, and a
`command` entry matching only `^(Bash|Write|Edit|MultiEdit|NotebookEdit)$` that runs
`bin/glance-approve.mjs`. PreToolUse is the only blocking event, and a command hook is the only
documented way to return a deny decision, so the gate has to be a spawned process; keeping the
match narrow means the cost is paid only for calls that could actually need a tap.
- `PreToolUse` is wired **twice** — a recording entry for the timeline, and a second entry matching
only `^(Bash|Write|Edit|MultiEdit|NotebookEdit)$` that runs `bin/glance-approve.mjs`. PreToolUse
is the only blocking event, and a command hook is the only documented way to return a deny
decision; keeping the match narrow means the gate's cost is paid only for calls that could
actually need a tap. Its `timeout` is derived from `approval.timeoutMs` at generation time rather
than hand-copied, which is the other thing `sync-hooks` refreshes.
The hook scripts use nothing but the Node standard library and always exit 0 unless they are
deliberately denying.
deliberately denying — including when the daemon rejects their token.
## Deliberately omitted
+20 -17
View File
@@ -10,7 +10,7 @@
import fs from "node:fs";
import path from "node:path";
import { spawn } from "node:child_process";
import { spawn, spawnSync } from "node:child_process";
import {
PLUGIN_ROOT,
baseUrl,
@@ -124,6 +124,12 @@ switch (cmd) {
console.log(` watchers : ${s.watchers}`);
console.log(` sessions : ${s.sessions}`);
console.log(` events kept : ${s.events}`);
if (s.hookAuthOk === false) {
console.log(
"\n ! hook auth mismatch: $GLANCE_HOME/hook.secret no longer matches what the daemon" +
"\n loaded, so events are being dropped. Restart it: glance stop && glance up",
);
}
if (s.devices === 0) console.log("\nNo device enrolled yet. Run: glance enroll");
break;
}
@@ -200,22 +206,19 @@ switch (cmd) {
}
case "sync-hooks": {
const file = path.join(PLUGIN_ROOT, "hooks", "hooks.json");
const doc = JSON.parse(fs.readFileSync(file, "utf8"));
let changed = 0;
for (const groups of Object.values(doc.hooks ?? {})) {
for (const group of groups) {
for (const h of group.hooks ?? []) {
if (h.type === "http" && typeof h.url === "string") {
const next = h.url.replace(/127\.0\.0\.1:\d+/, `127.0.0.1:${cfg.port}`);
if (next !== h.url) changed++;
h.url = next;
}
}
}
// hooks.json is generated, not edited: regenerate it from hooks/hooks.template.json.
// The port is not baked into it any more — the hook scripts read config.json themselves —
// so the thing this actually refreshes is the approval gate's timeout, plus the hook
// secret if it has gone missing.
const { status } = spawnSync(
process.execPath,
[path.join(PLUGIN_ROOT, "scripts", "gen-hooks.mjs")],
{ stdio: "inherit" },
);
if (status !== 0) process.exit(status ?? 1);
if (await isDaemonUp(cfg)) {
console.log("restart the daemon to pick up config changes: glance stop && glance up");
}
fs.writeFileSync(file, JSON.stringify(doc, null, 2) + "\n");
console.log(`rewrote ${changed} hook url(s) to port ${cfg.port}`);
break;
}
@@ -241,7 +244,7 @@ switch (cmd) {
glance devices list enrolled devices
glance revoke <id-prefix> revoke a device
glance approval <off|risky|all> remote approval policy
glance sync-hooks rewrite hook urls after a port change
glance sync-hooks regenerate hooks/hooks.json from the template
glance logs tail the daemon log
`);
}
+21 -4
View File
@@ -10,7 +10,15 @@
* call Grok was already about to make. This hook can never introduce a new command.
*/
import { baseUrl, envEnvelope, postJson, readConfig, readStdinJson } from "./glance-lib.mjs";
import {
approvalHookTimeoutSecs,
baseUrl,
envEnvelope,
hookHeaders,
postJson,
readConfig,
readStdinJson,
} from "./glance-lib.mjs";
function allow() {
process.exit(0);
@@ -28,11 +36,20 @@ function deny(reason) {
const payload = envEnvelope(await readStdinJson());
const cfg = readConfig();
// Stay inside the hook timeout declared in hooks/hooks.json (125s).
const waitMs = Math.min(115_000, Number(cfg.approval?.timeoutMs ?? 90_000) + 15_000);
// Finish inside the hook timeout that scripts/gen-hooks.mjs wrote into hooks.json, with room
// to spare: if Grok Build kills us first, the fail-open path below never gets to run.
const waitMs = Math.min(
approvalHookTimeoutSecs(cfg) * 1000 - 10_000,
Number(cfg.approval?.timeoutMs ?? 90_000) + 15_000,
);
try {
const { data } = await postJson(`${baseUrl(cfg)}/hook/approve`, payload, waitMs);
const { data } = await postJson(
`${baseUrl(cfg)}/hook/approve`,
payload,
waitMs,
hookHeaders(),
);
if (data && data.decision === "deny") deny(data.reason);
allow();
} catch {
+59 -2
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@@ -8,6 +8,7 @@
import fs from "node:fs";
import path from "node:path";
import os from "node:os";
import crypto from "node:crypto";
import { fileURLToPath } from "node:url";
export const PLUGIN_ROOT = path.resolve(fileURLToPath(import.meta.url), "../..");
@@ -43,6 +44,62 @@ export function baseUrl(cfg = readConfig()) {
return `http://127.0.0.1:${cfg.port}`;
}
/** Header the daemon expects on /hook/*; kept in step with server/src/auth.ts. */
export const HOOK_HEADER = "x-glance-hook";
/**
* The shared secret that admits a caller to /hook/*. Read fresh on every invocation so a
* regenerated secret is picked up without touching hooks.json.
*
* `create` is used by the build-time generator; the hook scripts pass false and simply get
* null when there is no secret yet. That is deliberate: a hook must never be the thing that
* creates state, and a missing secret has to degrade to "no telemetry", not "no tool call".
*/
export function hookSecret({ create = false } = {}) {
const file = path.join(glanceHome(), "hook.secret");
for (let attempt = 0; attempt < 2; attempt++) {
try {
const existing = fs.readFileSync(file, "utf8").trim();
if (existing) return existing;
} catch {
/* fall through */
}
if (!create) return null;
fs.mkdirSync(glanceHome(), { recursive: true, mode: 0o700 });
const token = crypto.randomBytes(32).toString("base64url");
try {
// Exclusive: if the daemon created one a millisecond ago, read theirs instead.
fs.writeFileSync(file, token + "\n", { mode: 0o600, flag: "wx" });
return token;
} catch {
/* lost the race; loop re-reads */
}
}
try {
return fs.readFileSync(file, "utf8").trim() || null;
} catch {
return null;
}
}
export function hookHeaders() {
const token = hookSecret();
return token ? { [HOOK_HEADER]: token } : {};
}
/**
* How long the PreToolUse approval hook is allowed to run, in seconds.
*
* One formula, two consumers: scripts/gen-hooks.mjs writes it into hooks.json as the hook's
* `timeout`, and glance-approve.mjs derives its own wait from it. They must agree — if the
* script outlives its hook timeout, Grok Build kills it and the fail-open path never runs.
*/
export function approvalHookTimeoutSecs(cfg = readConfig()) {
const ms = Number(cfg.approval?.timeoutMs ?? 90_000);
const base = Number.isFinite(ms) && ms > 0 ? ms : 90_000;
return Math.ceil(base / 1000) + 35;
}
/** Read the hook payload that Grok Build writes to stdin. Returns {} if there is none. */
export async function readStdinJson() {
if (process.stdin.isTTY) return {};
@@ -77,10 +134,10 @@ export function envEnvelope(payload) {
};
}
export async function postJson(url, body, timeoutMs) {
export async function postJson(url, body, timeoutMs, extraHeaders = {}) {
const res = await fetch(url, {
method: "POST",
headers: { "content-type": "application/json" },
headers: { "content-type": "application/json", ...extraHeaders },
body: JSON.stringify(body),
signal: AbortSignal.timeout(timeoutMs),
});
+35
View File
@@ -0,0 +1,35 @@
#!/usr/bin/env node
/**
* Passive recorder hook: POST one lifecycle event into the daemon and get out of the way.
*
* Wired to every observed event. This used to be a `type: "http"` hook — no process spawn at
* all — until it turned out that Grok Build's http runner validates the URL against its SSRF
* rules and rejects any scheme that is not https (crates/codegen/xai-grok-hooks/src/runner/
* http.rs, `validate_hook_url`). The daemon speaks plain http on loopback, so an http hook
* could never reach it: those hooks were failing validation, silently, on every event.
*
* A command hook costs a Node start (~40ms) per event, and buys back the ability to send an
* authentication header, which the http runner has no config surface for.
*
* Always exits 0. A dashboard must never be the reason a tool call fails.
*/
import {
baseUrl,
envEnvelope,
hookHeaders,
postJson,
readConfig,
readStdinJson,
} from "./glance-lib.mjs";
try {
const payload = envEnvelope(await readStdinJson());
const cfg = readConfig();
// Short: if the daemon is not listening this must fail fast, not hold up the tool call.
await postJson(`${baseUrl(cfg)}/hook/record`, payload, 2000, hookHeaders());
} catch {
// Daemon down, no secret yet, malformed payload — all the same answer: carry on.
}
process.exit(0);
+4 -1
View File
@@ -14,6 +14,7 @@ import {
baseUrl,
envEnvelope,
glanceHome,
hookHeaders,
isDaemonUp,
postJson,
readConfig,
@@ -59,7 +60,9 @@ const cfg = readConfig();
try {
const up = await ensureDaemon(cfg);
if (up) {
await postJson(`${baseUrl(cfg)}/hook/record`, payload, 2500);
// hookHeaders() is read here, not at import time: on a first-ever run the daemon we just
// spawned is what created hook.secret.
await postJson(`${baseUrl(cfg)}/hook/record`, payload, 2500, hookHeaders());
}
} catch {
// Fail open, always.
+73 -24
View File
@@ -1,14 +1,39 @@
{
"_comment": [
"grok-glance hook wiring.",
"Passive events use type=http: they POST straight into the daemon with no process spawn,",
"so they cost ~nothing per tool call and fail open if the daemon is not running.",
"SessionStart uses type=command because it is what boots the daemon.",
"PreToolUse is wired twice on purpose: an http entry records every tool call for the",
"timeline, and a command entry gates only risky tools, because only a command hook has a",
"documented way to return a deny decision.",
"If you change the port in ~/.grok/glance/config.json, run `glance sync-hooks` to rewrite",
"the URLs below, or edit them by hand."
"TEMPLATE. Do not edit hooks/hooks.json by hand - it is generated from this file by",
"`scripts/gen-hooks.mjs`, which runs as part of `npm run build` and on `glance sync-hooks`.",
"",
"Everything is a `command` hook, including the 13 passive recorders. That is not a style",
"choice: an `http` hook cannot reach this daemon by any route. Grok Build's http runner",
"(xai-grok-hooks/src/runner/http.rs, `validate_hook_url`) rejects every scheme but https,",
"then resolves the host and refuses the resolved address if it is private, link-local or",
"CGNAT - so plain http on loopback is out, and so is the tailnet, because *.ts.net resolves",
"into 100.64/10 (and fd7a::/48, inside the blocked fc00::/7). Pointing a hook at the public",
"https origin therefore fails upstream, before a request is ever sent. The runner also sends",
"no request header but Content-Type, so such a hook could not authenticate itself even if it",
"could connect.",
"",
"A command hook has none of those problems: it is a local process, so there is no URL to",
"validate, no proxy in the path, and it can present the shared secret. It costs one Node",
"start (~40ms) per event.",
"",
"SessionStart boots the daemon. PreToolUse is wired twice on purpose: one entry records",
"every call for the timeline, and a second, narrowly matched entry runs the approval gate,",
"because PreToolUse is the only blocking event and only a command hook can return a deny.",
"",
"Placeholders, written in the template as a name wrapped in double braces:",
" APPROVAL_TIMEOUT_SECS derived from approval.timeoutMs in ~/.grok/glance/config.json.",
" HOOK_TOKEN the secret from ~/.grok/glance/hook.secret, for a caller that",
" cannot set a header: the daemon accepts it as a ?k= query",
" parameter too. Nothing below uses it and no http hook can (see",
" above); it stays because the daemon's ?k= path is real. Note the",
" daemon also refuses any /hook/* request carrying x-forwarded-*,",
" so a reverse-proxied transport is out as well. Using this",
" placeholder makes the generated hooks.json secret-bearing, so",
" gen-hooks writes it 0600 and it must not be committed.",
"",
"Do not spell those names with their braces anywhere in this comment block: the comment is",
"copied verbatim into hooks.json, and substitution would happily expand it there too."
],
"hooks": {
"SessionStart": [
@@ -26,9 +51,9 @@
{
"hooks": [
{
"type": "http",
"url": "http://127.0.0.1:8791/hook/record",
"timeout": 3
"type": "command",
"command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"",
"timeout": 5
}
]
},
@@ -45,62 +70,86 @@
],
"PostToolUse": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PostToolUseFailure": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"UserPromptSubmit": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PermissionDenied": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"Notification": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"Stop": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"StopFailure": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SubagentStart": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SubagentStop": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PreCompact": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PostCompact": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SessionEnd": [
{
"hooks": [{ "type": "http", "url": "http://127.0.0.1:8791/hook/record", "timeout": 3 }]
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
]
}
+156
View File
@@ -0,0 +1,156 @@
{
"_comment": [
"TEMPLATE. Do not edit hooks/hooks.json by hand - it is generated from this file by",
"`scripts/gen-hooks.mjs`, which runs as part of `npm run build` and on `glance sync-hooks`.",
"",
"Everything is a `command` hook, including the 13 passive recorders. That is not a style",
"choice: an `http` hook cannot reach this daemon by any route. Grok Build's http runner",
"(xai-grok-hooks/src/runner/http.rs, `validate_hook_url`) rejects every scheme but https,",
"then resolves the host and refuses the resolved address if it is private, link-local or",
"CGNAT - so plain http on loopback is out, and so is the tailnet, because *.ts.net resolves",
"into 100.64/10 (and fd7a::/48, inside the blocked fc00::/7). Pointing a hook at the public",
"https origin therefore fails upstream, before a request is ever sent. The runner also sends",
"no request header but Content-Type, so such a hook could not authenticate itself even if it",
"could connect.",
"",
"A command hook has none of those problems: it is a local process, so there is no URL to",
"validate, no proxy in the path, and it can present the shared secret. It costs one Node",
"start (~40ms) per event.",
"",
"SessionStart boots the daemon. PreToolUse is wired twice on purpose: one entry records",
"every call for the timeline, and a second, narrowly matched entry runs the approval gate,",
"because PreToolUse is the only blocking event and only a command hook can return a deny.",
"",
"Placeholders, written in the template as a name wrapped in double braces:",
" APPROVAL_TIMEOUT_SECS derived from approval.timeoutMs in ~/.grok/glance/config.json.",
" HOOK_TOKEN the secret from ~/.grok/glance/hook.secret, for a caller that",
" cannot set a header: the daemon accepts it as a ?k= query",
" parameter too. Nothing below uses it and no http hook can (see",
" above); it stays because the daemon's ?k= path is real. Note the",
" daemon also refuses any /hook/* request carrying x-forwarded-*,",
" so a reverse-proxied transport is out as well. Using this",
" placeholder makes the generated hooks.json secret-bearing, so",
" gen-hooks writes it 0600 and it must not be committed.",
"",
"Do not spell those names with their braces anywhere in this comment block: the comment is",
"copied verbatim into hooks.json, and substitution would happily expand it there too."
],
"hooks": {
"SessionStart": [
{
"hooks": [
{
"type": "command",
"command": "node \"$GROK_PLUGIN_ROOT/bin/glance-up.mjs\"",
"timeout": 20
}
]
}
],
"PreToolUse": [
{
"hooks": [
{
"type": "command",
"command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"",
"timeout": 5
}
]
},
{
"matcher": "^(Bash|Write|Edit|MultiEdit|NotebookEdit)$",
"hooks": [
{
"type": "command",
"command": "node \"$GROK_PLUGIN_ROOT/bin/glance-approve.mjs\"",
"timeout": "{{APPROVAL_TIMEOUT_SECS}}"
}
]
}
],
"PostToolUse": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PostToolUseFailure": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"UserPromptSubmit": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PermissionDenied": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"Notification": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"Stop": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"StopFailure": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SubagentStart": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SubagentStop": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PreCompact": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"PostCompact": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
],
"SessionEnd": [
{
"hooks": [
{ "type": "command", "command": "node \"$GROK_PLUGIN_ROOT/bin/glance-record.mjs\"", "timeout": 5 }
]
}
]
}
}
+2 -1
View File
@@ -8,9 +8,10 @@
"node": ">=20"
},
"scripts": {
"build": "npm run build:server && npm run build:web",
"build": "npm run build:server && npm run build:web && npm run build:hooks",
"build:server": "tsc -p tsconfig.server.json",
"build:web": "tsc -p tsconfig.web.json && vite build",
"build:hooks": "node scripts/gen-hooks.mjs",
"dev": "vite",
"start": "node dist/server/index.js",
"glance": "node bin/glance"
+141
View File
@@ -0,0 +1,141 @@
#!/usr/bin/env node
/**
* Generate hooks/hooks.json from hooks/hooks.template.json.
*
* Runs as part of `npm run build`, and again on `glance sync-hooks`. Two jobs:
*
* 1. Make sure the /hook/* shared secret exists (mode 0600, in $GLANCE_HOME). The daemon
* requires it; without it the hook scripts are just anonymous POSTs, which is what this
* whole mechanism exists to stop.
* 2. Substitute the placeholders the template declares, so values that are really derived
* from config.json - the approval hook's timeout above all - stop being hand-copied
* constants that drift.
*
* It also refuses to emit a hook that cannot work. An `http` handler pointed at a non-https
* URL is the specific mistake that made every passive hook in this plugin a no-op for a
* while: Grok Build's http runner puts every URL through SSRF validation and rejects any
* other scheme outright (xai-grok-hooks/src/runner/http.rs, `validate_hook_url`).
*/
import fs from "node:fs";
import path from "node:path";
import { PLUGIN_ROOT, approvalHookTimeoutSecs, hookSecret, readConfig } from "../bin/glance-lib.mjs";
const TEMPLATE = path.join(PLUGIN_ROOT, "hooks", "hooks.template.json");
const OUTPUT = path.join(PLUGIN_ROOT, "hooks", "hooks.json");
const cfg = readConfig();
const token = hookSecret({ create: true });
if (!token) {
console.error(`gen-hooks: could not create the hook secret in ${process.env.GLANCE_HOME ?? "~/.grok/glance"}`);
process.exit(1);
}
const timeoutSecs = approvalHookTimeoutSecs(cfg);
let text = fs.readFileSync(TEMPLATE, "utf8");
// The quoted form first, so a JSON-valid template can carry a value that must end up numeric.
text = text
.split(`"{{APPROVAL_TIMEOUT_SECS}}"`)
.join(String(timeoutSecs))
.split("{{APPROVAL_TIMEOUT_SECS}}")
.join(String(timeoutSecs));
const embedsToken = text.includes("{{HOOK_TOKEN}}");
text = text.split("{{HOOK_TOKEN}}").join(token);
// Trust the emitted bytes, not the placeholder: a template that mentions the placeholder in a
// comment would otherwise ship the real secret in a world-readable file. (It did once.)
const tokenIsInOutput = text.includes(token);
if (tokenIsInOutput && !embedsToken) {
console.error("gen-hooks: the hook secret leaked into hooks.json from somewhere unexpected");
process.exit(1);
}
const leftover = text.match(/\{\{[A-Z_]+\}\}/);
if (leftover) {
console.error(`gen-hooks: unknown placeholder ${leftover[0]} in hooks.template.json`);
process.exit(1);
}
/* ------------------------------------------------------------------ validate */
let doc;
try {
doc = JSON.parse(text);
} catch (err) {
console.error(`gen-hooks: template did not produce valid JSON: ${err.message}`);
process.exit(1);
}
const problems = [];
let handlers = 0;
for (const [event, groups] of Object.entries(doc.hooks ?? {})) {
if (!Array.isArray(groups)) {
problems.push(`${event}: expected an array of matcher groups`);
continue;
}
for (const group of groups) {
for (const h of group.hooks ?? []) {
handlers++;
const where = `${event} -> ${h.command ?? h.url ?? "(no target)"}`;
if (h.type !== "command" && h.type !== "http") {
problems.push(`${where}: type must be "command" or "http", got ${JSON.stringify(h.type)}`);
continue;
}
if (typeof h.timeout !== "number" || !Number.isFinite(h.timeout) || h.timeout <= 0) {
problems.push(`${where}: timeout must be a positive number of seconds`);
}
if (h.type === "http") {
// The runner rejects every scheme but https, and treats RFC1918 / CGNAT / link-local
// targets as SSRF. That rules out both loopback-over-http and Tailscale's 100.64/10.
if (!/^https:\/\//.test(h.url ?? "")) {
problems.push(
`${where}: http handlers must use an https:// URL - Grok Build's SSRF check ` +
`rejects anything else, so this hook would never fire`,
);
}
} else {
const script = /bin\/([A-Za-z0-9._-]+)/.exec(h.command ?? "");
if (!script) {
problems.push(`${where}: could not tell which script this command runs`);
} else if (!fs.existsSync(path.join(PLUGIN_ROOT, "bin", script[1]))) {
problems.push(`${where}: bin/${script[1]} does not exist`);
}
}
}
}
}
if (problems.length) {
console.error("gen-hooks: refusing to write hooks.json\n");
for (const p of problems) console.error(` - ${p}`);
process.exit(1);
}
/* --------------------------------------------------------------------- write */
const mode = tokenIsInOutput ? 0o600 : 0o644;
const previous = fs.existsSync(OUTPUT) ? fs.readFileSync(OUTPUT, "utf8") : null;
if (previous === text) {
// Leave the mtime alone: a no-op build should not look like a change.
fs.chmodSync(OUTPUT, mode);
console.log(`hooks.json already current (${handlers} handlers, approval timeout ${timeoutSecs}s)`);
} else {
fs.writeFileSync(OUTPUT, text, { mode });
fs.chmodSync(OUTPUT, mode);
console.log(
`wrote hooks/hooks.json - ${handlers} handlers, approval timeout ${timeoutSecs}s` +
(previous === null ? " (new file)" : ""),
);
}
if (tokenIsInOutput) {
console.warn(
"gen-hooks: hooks.json now contains the hook secret (via the HOOK_TOKEN placeholder); it is " +
"mode 0600 and must not be committed.",
);
}
+4
View File
@@ -5,6 +5,10 @@ import type { IncomingMessage } from "node:http";
export const SESSION_COOKIE = "glance_session";
export const CSRF_HEADER = "x-glance-csrf";
/** Shared-secret header presented by the hook scripts on /hook/*. */
export const HOOK_HEADER = "x-glance-hook";
/** Query-string carrier for the same secret, for hooks that cannot set headers. */
export const HOOK_QUERY_PARAM = "k";
export function parseCookies(header: string | undefined): Record<string, string> {
const out: Record<string, string> = {};
+3
View File
@@ -43,6 +43,9 @@ export const paths = {
get adminToken() {
return path.join(glanceHome(), "admin.token");
},
get hookSecret() {
return path.join(glanceHome(), "hook.secret");
},
get events() {
return path.join(glanceHome(), "events.jsonl");
},
+44 -6
View File
@@ -3,10 +3,13 @@
*
* One small http server with three kinds of caller:
*
* /hook/* the plugin's hook scripts, on loopback. /hook/approve is the blocking one.
* /hook/* the plugin's hook scripts, gated by the shared secret in hook.secret.
* /api/* the web app, gated by a passkey-backed cookie session.
* /local/* the `glance` CLI, gated by a rotating admin token on disk.
*
* None of the three trusts the source address: `tailscale serve` proxies tailnet traffic to
* 127.0.0.1, so every caller looks local.
*
* Everything the hooks touch is written to fail open: if this process is confused, wedged, or
* gone, Grok Build keeps working.
*/
@@ -28,6 +31,8 @@ import {
import {
CSRF_HEADER,
EnrollmentCodes,
HOOK_HEADER,
HOOK_QUERY_PARAM,
RateLimiter,
SESSION_COOKIE,
buildSessionCookie,
@@ -47,7 +52,9 @@ import { SESSION_TTL_MS, WebAuthnService } from "./webauthn.js";
import {
destroyAuthSession,
deviceList,
hookSecret,
lookupAuthSession,
readHookSecretFromDisk,
revokeCredentials,
rotateAdminToken,
sessionSecret,
@@ -60,6 +67,7 @@ ensureHome();
const cfg = loadConfig();
const secret = sessionSecret();
const adminToken = rotateAdminToken();
const hookToken = hookSecret();
const webauthn = new WebAuthnService(cfg);
const codes = new EnrollmentCodes();
@@ -93,14 +101,36 @@ function currentSession(req: http.IncomingMessage): Session | null {
return { token, credentialId: record.credentialId, label: record.label };
}
function isAdmin(req: http.IncomingMessage): boolean {
const provided = header(req, "x-glance-admin");
function sameSecret(provided: string | undefined | null, expected: string): boolean {
if (!provided) return false;
const a = Buffer.from(provided);
const b = Buffer.from(adminToken);
const b = Buffer.from(expected);
return a.length === b.length && crypto.timingSafeEqual(a, b);
}
function isAdmin(req: http.IncomingMessage): boolean {
return sameSecret(header(req, "x-glance-admin"), adminToken);
}
/**
* Is this really one of our hook scripts?
*
* "It came from 127.0.0.1" proves nothing: `tailscale serve` proxies tailnet traffic to
* loopback, so without a check anyone on the tailnet could POST forged events into the
* timeline and answer /hook/approve on your behalf. Two independent barriers:
*
* 1. A shared secret from $GLANCE_HOME/hook.secret (mode 0600), presented as a header or,
* for hook types that cannot set one, as `?k=`. Compared in constant time.
* 2. The request must not have been proxied. Tailscale stamps `x-forwarded-*` on anything
* it tunnels, so their presence means the caller is not a local process — which no
* real hook ever is. This keeps a leaked secret from being usable off-box.
*/
function isHookCaller(req: http.IncomingMessage, url: URL): boolean {
if (header(req, "x-forwarded-for") || header(req, "x-forwarded-proto")) return false;
const provided = header(req, HOOK_HEADER) ?? url.searchParams.get(HOOK_QUERY_PARAM);
return sameSecret(provided, hookToken);
}
/**
* `application/json` is not a CORS-safelisted content type, so requiring it exactly means a
* hostile page cannot post here without a preflight we never answer. The custom header on
@@ -154,6 +184,11 @@ async function handle(req: http.IncomingMessage, res: http.ServerResponse): Prom
out.json(405, { error: "post json" });
return;
}
// Before reading a body: an unauthenticated caller gets to spend nothing here.
if (!isHookCaller(req, url)) {
out.json(403, { error: "hook token required" });
return;
}
const payload = ((await readJson<HookPayload>(req)) ?? {}) as HookPayload;
if (p === "/hook/record") {
@@ -163,8 +198,8 @@ async function handle(req: http.IncomingMessage, res: http.ServerResponse): Prom
}
if (p === "/hook/approve") {
// Note: this deliberately does not ingest an event. The PreToolUse http hook already
// recorded the tool call; recording it here too would double every entry.
// Note: this deliberately does not ingest an event. The PreToolUse recording hook
// already logged the tool call; recording it here too would double every entry.
const decision = await broker.request(payload);
out.json(200, decision);
return;
@@ -194,6 +229,9 @@ async function handle(req: http.IncomingMessage, res: http.ServerResponse): Prom
events: state.eventCount,
webBuilt: webBuildExists(),
home: paths.home,
// Would a hook script authenticate right now? The daemon holds the token it read at
// startup; if the file has since changed or gone, recording is silently dropping.
hookAuthOk: sameSecret(readHookSecretFromDisk(), hookToken),
});
return;
}
+41
View File
@@ -69,6 +69,47 @@ export function rotateAdminToken(): string {
return token;
}
/**
* Token the hook scripts present on /hook/*. Unlike `admin.token` this is *not* rotated on
* every start: hook scripts are separate short-lived processes that read the file per
* invocation, and a rotation mid-session would 403 whatever was already in flight.
*
* It exists because `tailscale serve` proxies tailnet traffic to 127.0.0.1, so "the request
* came from loopback" says nothing about who sent it. Without this, anyone on the tailnet
* could forge timeline events and answer approval prompts.
*
* Created exclusively (`wx`) so two hooks racing on a fresh home cannot end up with
* different values — the loser re-reads the winner's file.
*/
export function hookSecret(): string {
ensureHome();
for (let attempt = 0; attempt < 2; attempt++) {
try {
const existing = fs.readFileSync(paths.hookSecret, "utf8").trim();
if (existing) return existing;
} catch {
/* create below */
}
const token = crypto.randomBytes(32).toString("base64url");
try {
fs.writeFileSync(paths.hookSecret, token + "\n", { mode: 0o600, flag: "wx" });
return token;
} catch {
// Lost the race (or the file appeared between the read and the write): read it back.
}
}
return fs.readFileSync(paths.hookSecret, "utf8").trim();
}
/** Whatever is on disk right now, for diagnostics. Never creates the file. */
export function readHookSecretFromDisk(): string | null {
try {
return fs.readFileSync(paths.hookSecret, "utf8").trim() || null;
} catch {
return null;
}
}
/* -------------------------------------------------------------- credentials */
export function listCredentials(): StoredCredential[] {
+8 -5
View File
@@ -34,7 +34,7 @@ glance set-origin <https-url> # set the public origin and WebAuthn RP ID
glance devices # list enrolled devices
glance revoke <id-prefix> # revoke one
glance approval <off|risky|all> # remote approve/deny policy
glance sync-hooks # rewrite hook URLs after changing the port
glance sync-hooks # regenerate hooks/hooks.json from hooks/hooks.template.json
```
## Getting it onto a phone
@@ -63,8 +63,8 @@ and wait for a tap on the phone. Defaults that matter:
- Nothing waits unless a phone is actually watching the dashboard (`requireWatcher`).
- If nobody answers within 90s the call is **allowed**, not denied. Flip that on the phone's
settings panel if you want the opposite.
- Every failure path is fail-open: daemon down, timeout, bad JSON — the tool call proceeds. This
is a convenience gate, not a security boundary.
- Every failure path is fail-open: daemon down, timeout, bad JSON, a rejected hook secret — the tool
call proceeds. This is a convenience gate, not a security boundary.
`glance approval off` (the default) means Grok Build never blocks on the phone.
@@ -73,8 +73,11 @@ and wait for a tap on the phone. Defaults that matter:
- **"not running"** → `glance up`, then `glance logs`.
- **Passkey prompt fails with a security error** → the phone is on a hostname the RP ID does not
cover. Compare `glance status`'s `rp id` with the hostname in the phone's address bar.
- **Dashboard loads but shows nothing** → hooks are not firing. Check that the port in
`hooks/hooks.json` matches `~/.grok/glance/config.json`; `glance sync-hooks` fixes it.
- **Dashboard loads but shows nothing** → hooks are not firing. `glance status` warns if the hook
secret in `$GLANCE_HOME/hook.secret` no longer matches the one the daemon loaded (events are being
dropped with a 403); `glance stop && glance up` fixes that. Otherwise check that
`hooks/hooks.json` exists and is registered — it is generated, so `glance sync-hooks` rebuilds it
from the template.
- **Page says "run npm install && npm run build"** → the web bundle is missing; build it.
## What it deliberately does not do