2 Commits

Author SHA1 Message Date
Garry Tan 54d4cde773 security: tunnel dual-listener + SSRF + envelope + path wave (v1.6.0.0) (#1137)
* refactor(security): loosen /connect rate limit from 3/min to 300/min

Setup keys are 24 random bytes (unbruteforceable), so a tight rate limit
does not meaningfully prevent key guessing. It exists only to cap
bandwidth, CPU, and log-flood damage from someone who discovered the
ngrok URL. A legitimate pair-agent session hits /connect once; 300/min
is 60x that pattern and never hit accidentally.

3/min caused pairing to fail on any retry flow (network blip, second
paired client) with no upside. Per-IP tracking was considered and
rejected — adds a bounded Map + LRU for defense already adequate at the
global layer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(security): add tunnel-denial-log module for attack visibility

Append-only log of tunnel-surface auth denials to
~/.gstack/security/attempts.jsonl. Gives operators visibility into who
is probing tunneled daemons so the next security wave can be driven by
real attack data instead of speculation.

Design notes:
- Async via fs.promises.appendFile. Never appendFileSync — blocking the
  event loop on every denial during a flood is what an attacker wants
  (prior learning: sync-audit-log-io, 10/10 confidence).
- In-process rate cap at 60 writes/minute globally. Excess denials are
  counted in memory but not written to disk — prevents disk DoS.
- Writes to the same ~/.gstack/security/attempts.jsonl used by the
  prompt-injection attempt log. File rotation is handled by the existing
  security pipeline (10MB, 5 generations).

No consumers in this commit; wired up in the dual-listener refactor that
follows.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(security): dual-listener tunnel architecture

The /health endpoint leaked AUTH_TOKEN to any caller that hit the ngrok
URL (spoofing chrome-extension:// origin, or catching headed mode).
Surfaced by @garagon in PR #1026; the original fix was header-inference
on the single port. Codex's outside-voice review during /plan-ceo-review
called that approach brittle (ngrok header behavior could change, local
proxies would false-positive), and pushed for the structural fix.

This is that fix. Stop making /health a root-token bootstrap endpoint on
any surface the tunnel can reach. The server now binds two HTTP
listeners when a tunnel is active. The local listener (extension, CLI,
sidebar) stays on 127.0.0.1 and is never exposed to ngrok. ngrok
forwards only to the tunnel listener, which serves only /connect
(unauth, rate-limited) and /command with a locked allowlist of
browser-driving commands. Security property comes from physical port
separation, not from header inference — a tunnel caller cannot reach
/health or /cookie-picker or /inspector because they live on a
different TCP socket.

What this commit adds to browse/src/server.ts:
  * Surface type ('local' | 'tunnel') and TUNNEL_PATHS +
    TUNNEL_COMMANDS allowlists near the top of the file.
  * makeFetchHandler(surface) factory replacing the single fetch arrow;
    closure-captures the surface so the filter that runs before route
    dispatch knows which socket accepted the request.
  * Tunnel filter at dispatch entry: 404s anything not on TUNNEL_PATHS,
    403s root-token bearers with a clear pairing hint, 401s non-/connect
    requests that lack a scoped token. Every denial is logged via
    logTunnelDenial (from tunnel-denial-log).
  * GET /connect alive probe (unauth on both surfaces) so /pair and
    /tunnel/start can detect dead ngrok tunnels without reaching
    /health — /health is no longer tunnel-reachable.
  * Lazy tunnel listener lifecycle. /tunnel/start binds a dedicated
    Bun.serve on an ephemeral port, points ngrok.forward at THAT port
    (not the local port), hard-fails on bind error (no local fallback),
    tears down cleanly on ngrok failure. BROWSE_TUNNEL=1 startup uses
    the same pattern.
  * closeTunnel() helper — single teardown path for both the ngrok
    listener and the tunnel Bun.serve listener.
  * resolveNgrokAuthtoken() helper — shared authtoken lookup across
    /tunnel/start and BROWSE_TUNNEL=1 startup (was duplicated).
  * TUNNEL_COMMANDS check in /command dispatch: on the tunnel surface,
    commands outside the allowlist return 403 with a list of allowed
    commands as a hint.
  * Probe paths in /pair and /tunnel/start migrated from /health to
    GET /connect — the only unauth path reachable on the tunnel surface
    under the new architecture.

Test updates in browse/test/server-auth.test.ts:
  * /pair liveness-verify test: assert via closeTunnel() helper instead
    of the inline `tunnelActive = false; tunnelUrl = null` lines that
    the helper subsumes.
  * /tunnel/start cached-tunnel test: same closeTunnel() adaptation.

Credit
  Derived from PR #1026 by @garagon — thanks for flagging the critical
  bug that drove the architectural rewrite. The per-request
  isTunneledRequest approach from #1026 is superseded by physical port
  separation here; the underlying report remains the root cause for the
  entire v1.6.0.0 wave.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(security): add source-level guards for dual-listener architecture

23 source-level assertions that keep future contributors from silently
widening the tunnel surface during a routine refactor. Covers:

  * Surface type + tunnelServer state variable shape
  * TUNNEL_PATHS is a closed set of /connect, /command, /sidebar-chat
    (and NOT /health, /welcome, /cookie-picker, /inspector/*, /pair,
    /token, /refs, /activity/stream, /tunnel/{start,stop})
  * TUNNEL_COMMANDS includes browser-driving ops only (and NOT
    launch-browser, tunnel-start, token-mint, cookie-import, etc.)
  * makeFetchHandler(surface) factory exists and is wired to both
    listeners with the correct surface parameter
  * Tunnel filter runs BEFORE any route dispatch, with 404/403/401
    responses and logged denials for each reason
  * GET /connect returns {alive: true} unauth
  * /command dispatch enforces TUNNEL_COMMANDS on tunnel surface
  * closeTunnel() helper tears down ngrok + Bun.serve listener
  * /tunnel/start binds on ephemeral port, points ngrok at TUNNEL_PORT
    (not local port), hard-fails on bind error (no fallback), probes
    cached tunnel via GET /connect (not /health), tears down on
    ngrok.forward failure
  * BROWSE_TUNNEL=1 startup uses the dual-listener pattern
  * logTunnelDenial wired for all three denial reasons
  * /connect rate limit is 300/min, not 3/min

All 23 tests pass. Behavioral integration tests (spawn subprocess, real
network) live in the E2E suite that lands later in this wave.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* security: gate download + scrape through validateNavigationUrl (SSRF)

The `goto` command was correctly wired through validateNavigationUrl,
but `download` and `scrape` called page.request.fetch(url, ...) directly.
A caller with the default write scope could hit the /command endpoint
and ask the daemon to fetch http://169.254.169.254/latest/meta-data/
(AWS IMDSv1) or the GCP/Azure/internal equivalents. The response body
comes back as base64 or lands on disk where GET /file serves it.

Fix: call validateNavigationUrl(url) immediately before each
page.request.fetch() call site in download and in the scrape loop.
Same blocklist that already protects `goto`: file://, javascript:,
data:, chrome://, cloud metadata (IPv4 all encodings, IPv6 ULA,
metadata.*.internal).

Tests: extend browse/test/url-validation.test.ts with a source-level
guard that walks every `await page.request.fetch(` call site and
asserts a validateNavigationUrl call precedes it within the same
branch. Regression trips before code review if a future refactor
drops the gate.

* security: route splitForScoped through envelope sentinel escape

The scoped-token snapshot path in snapshot.ts built its untrusted
block by pushing the raw accessibility-tree lines between the literal
`═══ BEGIN UNTRUSTED WEB CONTENT ═══` / `═══ END UNTRUSTED WEB CONTENT ═══`
sentinels. The full-page wrap path in content-security.ts already
applied a zero-width-space escape on those exact strings to prevent
sentinel injection, but the scoped path skipped it.

Net effect: a page whose rendered text contains the literal sentinel
can close the envelope early from inside untrusted content and forge
a fake "trusted" block for the LLM. That includes fabricating
interactive `@eN` references the agent will act on.

Fix:
  * Extract the zero-width-space escape into a named, exported helper
    `escapeEnvelopeSentinels(content)` in content-security.ts.
  * Have `wrapUntrustedPageContent` call it (behavior unchanged on
    that path — same bytes out).
  * Import the helper in snapshot.ts and map it over `untrustedLines`
    in the `splitForScoped` branch before pushing the BEGIN sentinel.

Tests: add a describe block in content-security.test.ts that covers
  * `escapeEnvelopeSentinels` defuses BEGIN and END markers;
  * `escapeEnvelopeSentinels` leaves normal text untouched;
  * `wrapUntrustedPageContent` still emits exactly one real envelope
    pair when hostile content contains forged sentinels;
  * snapshot.ts imports the helper;
  * the scoped-snapshot branch calls `escapeEnvelopeSentinels` before
    pushing the BEGIN sentinel (source-level regression — if a future
    refactor reorders this, the test trips).

* security: extend hidden-element detection to all DOM-reading channels

The Confusion Protocol envelope wrap (`wrapUntrustedPageContent`)
covers every scoped PAGE_CONTENT_COMMAND, but the hidden-element
ARIA-injection detection layer only ran for `text`. Other DOM-reading
channels (html, links, forms, accessibility, attrs, data, media,
ux-audit) returned their output through the envelope with no hidden-
content filter, so a page serving a display:none div that instructs
the agent to disregard prior system messages, or an aria-label that
claims to put the LLM in admin mode, leaked the injection payload on
any non-text channel. The envelope alone does not mitigate this, and
the page itself never rendered the hostile content to the human
operator.

Fix:
  * New export `DOM_CONTENT_COMMANDS` in commands.ts — the subset of
    PAGE_CONTENT_COMMANDS that derives its output from the live DOM.
    Console and dialog stay out; they read separate runtime state.
  * server.ts runs `markHiddenElements` + `cleanupHiddenMarkers` for
    every scoped command in this set. `text` keeps its existing
    `getCleanTextWithStripping` path (hidden elements physically
    stripped before the read). All other channels keep their output
    format but emit flagged elements as CONTENT WARNINGS on the
    envelope, so the LLM sees what it would otherwise have consumed
    silently.
  * Hidden-element descriptions merge into `combinedWarnings`
    alongside content-filter warnings before the wrap call.

Tests: new describe block in content-security.test.ts covering
  * `DOM_CONTENT_COMMANDS` export shape and channel membership;
  * dispatch gates on `DOM_CONTENT_COMMANDS.has(command)`, not the
    literal `text` string;
  * hiddenContentWarnings plumbs into `combinedWarnings` and reaches
    wrapUntrustedPageContent;
  * DOM_CONTENT_COMMANDS is a strict subset of PAGE_CONTENT_COMMANDS.

Existing datamarking, envelope wrap, centralized-wrapping, and chain
security suites stay green (52 pass, 0 fail).

* security: validate --from-file payload paths for parity with direct paths

The direct `load-html <file>` path runs every caller-supplied file path
through validateReadPath() so reads stay confined to SAFE_DIRECTORIES
(cwd, TEMP_DIR). The `load-html --from-file <payload.json>` shortcut
and its sibling `pdf --from-file <payload.json>` skipped that check and
went straight to fs.readFileSync(). An MCP caller that picks the
payload path (or any caller whose payload argument is reachable from
attacker-influenced text) could use --from-file as a read-anywhere
escape hatch for the safe-dirs policy.

Fix: call validateReadPath(path.resolve(payloadPath)) before readFileSync
at both sites. Error surface mirrors the direct-path branch so ops and
agent errors stay consistent.

Test coverage in browse/test/from-file-path-validation.test.ts:
  - source-level: validateReadPath precedes readFileSync in the load-html
    --from-file branch (write-commands.ts) and the pdf --from-file parser
    (meta-commands.ts)
  - error-message parity: both sites reference SAFE_DIRECTORIES

Related security audit pattern: R3 F002 (validateNavigationUrl gap on
download/scrape) and R3 F008 (markHiddenElements gap on 10 DOM commands)
were the same shape — a defense that existed on the primary code path
but not its shortcut sibling. This PR closes the same class of gap on
the --from-file shortcuts.

* fix(design): escape url.origin when injecting into served HTML

serve.ts injected url.origin into a single-quoted JS string in
the response body. A local request with a crafted Host header
(e.g. Host: "evil'-alert(1)-'x") would break out of the string
and execute JS in the 127.0.0.1:<port> origin opened by the
design board. Low severity — bound to localhost, requires a
local attacker — but no reason not to escape.

Fix: JSON.stringify(url.origin) produces a properly quoted,
escaped JS string literal in one call.

Also includes Prettier reformatting (single→double quotes,
trailing commas, line wrapping) applied by the repo's
PostToolUse formatter hook. Security change is the one line
in the HTML injection; everything else is whitespace/style.

* fix(scripts): drop shell:true from slop-diff npx invocations

spawnSync('npx', [...], { shell: true }) invokes /bin/sh -c
with the args concatenated, subjecting them to shell parsing
(word splitting, glob expansion, metacharacter interpretation).
No user input reaches these calls today, so not exploitable —
but the posture is wrong: npx + shell args should be direct.

Fix: scope shell:true to process.platform === 'win32' where
npx is actually a .cmd requiring the shell. POSIX runs the
npx binary directly with array-form args.

Also includes Prettier reformatting (single→double quotes,
trailing commas, line wrapping) applied by the repo's
PostToolUse formatter hook. Security-relevant change is just
the two shell:true -> shell: process.platform === 'win32'
lines; everything else is whitespace/style.

* security(E3): gate GSTACK_SLUG on /welcome path traversal

The /welcome handler interpolates GSTACK_SLUG directly into the filesystem
path used to locate the project-local welcome page. Without validation, a
slug like "../../etc/passwd" would resolve to
~/.gstack/projects/../../etc/passwd/designs/welcome-page-20260331/finalized.html
— classic path traversal.

Not exploitable today: GSTACK_SLUG is set by the gstack CLI at daemon launch,
and an attacker would already need local env-var access to poison it. But
the gate is one regex (^[a-z0-9_-]+$), and a defense-in-depth pass costs us
nothing when the cost of being wrong is arbitrary file read via /welcome.

Fall back to the safe 'unknown' literal when the slug fails validation —
same fallback the code already uses when GSTACK_SLUG is unset. No behavior
change for legitimate slugs (they all match the regex).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* security(N1): replace ?token= SSE auth with HttpOnly session cookie

Activity stream and inspector events SSE endpoints accepted the root
AUTH_TOKEN via `?token=` query param (EventSource can't send Authorization
headers). URLs leak to browser history, referer headers, server logs,
crash reports, and refactoring accidents. Codex flagged this during the
/plan-ceo-review outside voice pass.

New auth model: the extension calls POST /sse-session with a Bearer token
and receives a view-only session cookie (HttpOnly, SameSite=Strict, 30-min
TTL). EventSource is opened with `withCredentials: true` so the browser
sends the cookie back on the SSE connection. The ?token= query param is
GONE — no more URL-borne secrets.

Scope isolation (prior learning cookie-picker-auth-isolation, 10/10
confidence): the SSE session cookie grants access to /activity/stream and
/inspector/events ONLY. The token is never valid against /command, /token,
or any mutating endpoint. A leaked cookie can watch activity; it cannot
execute browser commands.

Components
  * browse/src/sse-session-cookie.ts — registry: mint/validate/extract/
    build-cookie. 256-bit tokens, 30-min TTL, lazy expiry pruning,
    no imports from token-registry (scope isolation enforced by module
    boundary).
  * browse/src/server.ts — POST /sse-session mint endpoint (requires
    Bearer). /activity/stream and /inspector/events now accept Bearer
    OR the session cookie, and reject ?token= query param.
  * extension/sidepanel.js — ensureSseSessionCookie() bootstrap call,
    EventSource opened with withCredentials:true on both SSE endpoints.
    Tested via the source guards; behavioral test is the E2E pairing
    flow that lands later in the wave.
  * browse/test/sse-session-cookie.test.ts — 20 unit tests covering
    mint entropy, TTL enforcement, cookie flag invariants, cookie
    parsing from multi-cookie headers, and scope-isolation contract
    guard (module must not import token-registry).
  * browse/test/server-auth.test.ts — existing /activity/stream auth
    test updated to assert the new cookie-based gate and the absence
    of the ?token= query param.

Cookie flag choices:
  * HttpOnly: token not readable from page JS (mitigates XSS
    exfiltration).
  * SameSite=Strict: cookie not sent on cross-site requests (mitigates
    CSRF). Fine for SSE because the extension connects to 127.0.0.1
    directly.
  * Path=/: cookie scoped to the whole origin.
  * Max-Age=1800: 30 minutes, matches TTL. Extension re-mints on
    reconnect when daemon restarts.
  * Secure NOT set: daemon binds to 127.0.0.1 over plain HTTP. Adding
    Secure would block the browser from ever sending the cookie back.
    Add Secure when gstack ships over HTTPS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* security(N2): document Windows v20 ABE elevation path on CDP port

The existing comment around the cookie-import-browser --remote-debugging-port
launch claimed "threat model: no worse than baseline." That's wrong on
Windows with App-Bound Encryption v20. A same-user local process that
opens the cookie SQLite DB directly CANNOT decrypt v20 values (DPAPI
context is bound to the browser process). The CDP port lets them bypass
that: connect to the debug port, call Network.getAllCookies inside Chrome,
walk away with decrypted v20 cookies.

The correct fix is to switch from TCP --remote-debugging-port to
--remote-debugging-pipe so the CDP transport is a stdio pipe, not a
socket. That requires restructuring the CDP WebSocket client in this
module and Playwright doesn't expose the pipe transport out of the box.
Non-trivial, deferred from the v1.6.0.0 wave.

This commit updates the comment to correctly describe the threat and
points at the tracking issue. No code change to the launch itself.
Follow-up: #1136.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs(E2): document dual-listener tunnel architecture in ARCHITECTURE.md

Adds an explicit per-endpoint disposition table to the Security model
section, covering the v1.6.0.0 dual-listener refactor. Every HTTP
endpoint now has a documented local-vs-tunnel answer. Future audits
(and future contributors wondering "is it safe to add X to the tunnel
surface?") can read this instead of reverse-engineering server.ts.

Also documents:
  * Why physical port separation beats per-request header inference
    (ngrok behavior drift, local proxies can forge headers, etc.)
  * Tunnel surface denial logging → ~/.gstack/security/attempts.jsonl
  * SSE session cookie model (gstack_sse, 30-min TTL, stream-scope only,
    module-boundary-enforced scope isolation)
  * N2 non-goal for Windows v20 ABE via CDP port (tracking #1136)

No code changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(E1): end-to-end pair-agent flow against a spawned daemon

Spawns the browse daemon as a subprocess with BROWSE_HEADLESS_SKIP=1 so
the HTTP layer runs without a real browser.  Exercises:

  * GET /health — token delivery for chrome-extension origin, withheld
    otherwise (the F1 + PR #1026 invariant)
  * GET /connect — alive probe returns {alive:true} unauth
  * POST /pair — root Bearer required (403 without), returns setup_key
  * POST /connect — setup_key exchange mints a distinct scoped token
  * POST /command — 401 without auth
  * POST /sse-session — Bearer required, Set-Cookie has HttpOnly +
    SameSite=Strict (the N1 invariant)
  * GET /activity/stream — 401 without auth
  * GET /activity/stream?token= — 401 (the old ?token= query param is
    REJECTED, which is the whole point of N1)
  * GET /welcome — serves HTML, does not leak /etc/passwd content under
    the default 'unknown' slug (E3 regex gate)

12 behavioral tests, ~220ms end-to-end, no network dependencies, no
ngrok, no real browser.  This is the receipt for the wave's central
'pair-agent still works + the security boundary holds' claim.

Tunnel-port binding (/tunnel/start) is deliberately NOT exercised here
— it requires an ngrok authtoken and live network.  The dual-listener
route allowlist is covered by source-level guards in
dual-listener.test.ts; behavioral tunnel testing belongs in a separate
paid-evals harness.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* release(v1.6.0.0): bump VERSION + CHANGELOG for security wave

Architectural bump, not patch: dual-listener HTTP refactor changes the
daemon's tunnel-exposure model.  See CHANGELOG for the full release
summary (~950 words) covering the five root causes this wave closes:

  1. /health token leak over ngrok (F1 + E3 + test infra)
  2. /cookie-picker + /inspector exposed over the tunnel (F1)
  3. ?token=<ROOT> in SSE URLs leaking to logs/referer/history (N1)
  4. /welcome GSTACK_SLUG path traversal (E3)
  5. Windows v20 ABE elevation via CDP port (N2 — documented non-goal,
     tracked as #1136)

Plus the base PRs: SSRF gate (#1029), envelope sentinel escape (#1031),
DOM-channel hidden-element coverage (#1032), --from-file path validation
(#1103), and 2 commits from #1073 (@theqazi).

VERSION + package.json bumped to 1.6.0.0.  CHANGELOG entry covers
credits (@garagon, @Hybirdss, @HMAKT99, @theqazi), review lineage (CEO
→ Codex outside voice → Eng), and the non-goal tracking issue.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix: pre-landing review findings (4 auto-fixes)

Addresses 4 findings from the Claude adversarial subagent on the
v1.6.0.0 security wave diff.  No user-visible behavior change; all
are defense-in-depth hardening of newly-introduced code.

1. GET /connect rate-limited (was POST-only) [HIGH conf 8/10]
   Attacker discovering the ngrok URL could probe unlimited GETs for
   daemon enumeration.  Now shares the global /connect counter.

2. ngrok listener leak on tunnel startup failure [MEDIUM conf 8/10]
   If ngrok.forward() resolved but tunnelListener.url() or the
   state-file write threw, the Bun listener was torn down but the
   ngrok session was leaked.  Fixed in BOTH /tunnel/start and
   BROWSE_TUNNEL=1 startup paths.

3. GSTACK_SKILL_ROOT path-traversal gate [MEDIUM conf 8/10]
   Symmetric with E3's GSTACK_SLUG regex gate — reject values
   containing '..' before interpolating into the welcome-page path.

4. SSE session registry pruning [LOW conf 7/10]
   pruneExpired() only checked 10 entries per mint call.  Now runs
   on every validate too, checks 20 entries, with a hard 10k cap as
   backstop.  Prevents registry growth under sustained extension
   reconnect pressure.

Tests remain green (56/56 in sse-session-cookie + dual-listener +
pair-agent-e2e suites).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs: update project documentation for v1.6.0.0

Reflect the dual-listener tunnel architecture, SSE session cookies,
SSRF guards, and Windows v20 ABE non-goal across the three docs
users actually read for remote-agent and browser auth context:

- docs/REMOTE_BROWSER_ACCESS.md: rewrote Architecture diagram for
  dual listeners, fixed /connect rate limit (3/min → 300/min),
  removed stale "/health requires no auth" (now 404 on tunnel),
  added SSE cookie auth, expanded Security Model with tunnel
  allowlist, SSRF guards, /welcome path traversal defense, and
  the Windows v20 ABE tracking note.
- BROWSER.md: added dual-listener paragraph to Authentication and
  linked to ARCHITECTURE.md endpoint table. Replaced the stale
  ?token= SSE auth note with the HttpOnly gstack_sse cookie flow.
- CLAUDE.md: added Transport-layer security section above the
  sidebar prompt-injection stack so contributors editing server.ts,
  sse-session-cookie.ts, or tunnel-denial-log.ts see the load-bearing
  module boundaries before touching them.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(make-pdf): write --from-file payload to /tmp, not os.tmpdir()

make-pdf's browseClient wrote its --from-file payload to os.tmpdir(),
which is /var/folders/... on macOS. v1.6.0.0's PR #1103 cherry-pick
tightened browse load-html --from-file to validate against the
safe-dirs allowlist ([TEMP_DIR, cwd] where TEMP_DIR is '/tmp' on
macOS/Linux, os.tmpdir() on Windows). This closed a CLI/API parity
gap but broke make-pdf on macOS because /var/folders/... is outside
the allowlist.

Fix: mirror browse's TEMP_DIR convention — use '/tmp' on non-Windows,
os.tmpdir() on Windows. The make-pdf-gate CI failure on macOS-latest
(run 72440797490) is caused by exactly this: the payload file was
rejected by validateReadPath.

Verified locally: the combined-gate e2e test now passes after
rebuilding make-pdf/dist/pdf.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(sidebar): killAgent resets per-tab state; align tests with current agent event format

Two pre-existing bugs surfaced while running the full e2e suite on the
sec-wave branch.  Both pre-date v1.6.0.0 (same failures on main at
e23ff280) but blocked the ship verification, so fixing now.

### Bug 1: killAgent leaked stale per-tab state

`killAgent()` reset the legacy globals (agentProcess, agentStatus,
etc.) but never touched the per-tab `tabAgents` Map.  Meanwhile
`/sidebar-command` routes on `tabState.status` from that Map, not the
legacy globals.  Consequence: after a kill (including the implicit
kill in `/sidebar-session/new`), the next /sidebar-command on the
same tab saw `tabState.status === 'processing'` and fell into the
queue branch, silently NOT spawning an agent.  Integration tests that
called resetState between cases all failed with empty queues.

Fix: when targetTabId is supplied, reset that one tab's state; when
called without a tab (session-new, full kill), reset ALL tab states.
Matches the semantic boundary already used for the cancel-file write.

### Bug 2: sidebar-integration tests drifted from current event format

`agent events appear in /sidebar-chat` posted the raw Claude streaming
format (`{type: 'assistant', message: {content: [...]}}`) but
`processAgentEvent` in server.ts only handles the simplified types
that sidebar-agent.ts pre-processes into (text, text_delta, tool_use,
result, agent_error, security_event).  The architecture moved
pre-processing into sidebar-agent.ts at some point and this test
never got updated.  Fixed by sending the pre-processed `{type:
'text', text: '...'}` format — which is actually what the server sees
in production.

Also removed the `entry.prompt` URL-containment check in the
queue-write test.  The URL is carried on entry.pageUrl (metadata) by
design: the system prompt tells Claude to run `browse url` to fetch
the actual page rather than trust any URL in the prompt body.  That's
the URL-based prompt-injection defense.  The prompt SHOULD NOT
contain the URL, so the test assertion was wrong for the current
security posture.

### Verification

- `bun test browse/test/sidebar-integration.test.ts` → 13/13 pass
  (was 6/13 on both main and branch before this commit)
- Full `bun run test` → exit 0, zero fail markers
- No behavior change for production sidebar flows: killAgent was
  already supposed to return the agent to idle; it just wasn't fully
  doing so.  Per-tab reset now matches the documented semantics.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: gus <gustavoraularagon@gmail.com>
Co-authored-by: Mohammed Qazi <10266060+theqazi@users.noreply.github.com>
2026-04-21 21:58:27 -07:00
Garry Tan 8ca950f6f1 feat: content security — 4-layer prompt injection defense for pair-agent (#815)
* feat: token registry for multi-agent browser access

Per-agent scoped tokens with read/write/admin/meta command categories,
domain glob restrictions, rate limiting, expiry, and revocation. Setup
key exchange for the /pair-agent ceremony (5-min one-time key → 24h
session token). Idempotent exchange handles tunnel drops. 39 tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: integrate token registry + scoped auth into browse server

Server changes for multi-agent browser access:
- /connect endpoint: setup key exchange for /pair-agent ceremony
- /token endpoint: root-only minting of scoped sub-tokens
- /token/:clientId DELETE: revoke agent tokens
- /agents endpoint: list connected agents (root-only)
- /health: strips root token when tunnel is active (P0 security fix)
- /command: scope/rate/domain checks via token registry before dispatch
- Idle timer skips shutdown when tunnel is active

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: ngrok tunnel integration + @ngrok/ngrok dependency

BROWSE_TUNNEL=1 env var starts an ngrok tunnel after Bun.serve().
Reads NGROK_AUTHTOKEN from env or ~/.gstack/ngrok.env. Reads
NGROK_DOMAIN for dedicated domain (stable URL). Updates state
file with tunnel URL. Feasibility spike confirmed: SDK works in
compiled Bun binary.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: tab isolation for multi-agent browser access

Add per-tab ownership tracking to BrowserManager. Scoped agents
must create their own tab via newtab before writing. Unowned tabs
(pre-existing, user-opened) are root-only for writes. Read access
always allowed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: tab enforcement + POST /pair endpoint + activity attribution

Server-side tab ownership check blocks scoped agents from writing to
unowned tabs. Special-case newtab records ownership for scoped tokens.
POST /pair endpoint creates setup keys for the pairing ceremony.
Activity events now include clientId for attribution.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: pair-agent CLI command + instruction block generator

One command to pair a remote agent: $B pair-agent. Creates a setup
key via POST /pair, prints a copy-pasteable instruction block with
curl commands. Smart tunnel fallback (tunnel URL > auto-start >
localhost). Flags: --for HOST, --local HOST, --admin, --client NAME.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: tab isolation + instruction block generator tests

14 tests covering tab ownership lifecycle (access checks, unowned
tabs, transferTab) and instruction block generator (scopes, URLs,
admin flag, troubleshooting section). Fix server-auth test that
used fragile sliceBetween boundaries broken by new endpoints.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: bump version and changelog (v0.15.9.0)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: CSO security fixes — token leak, domain bypass, input validation

1. Remove root token from /health endpoint entirely (CSO #1 CRITICAL).
   Origin header is spoofable. Extension reads from ~/.gstack/.auth.json.
2. Add domain check for newtab URL (CSO #5). Previously only goto was
   checked, allowing domain-restricted agents to bypass via newtab.
3. Validate scope values, rateLimit, expiresSeconds in createToken()
   (CSO #4). Rejects invalid scopes and negative values.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: /pair-agent skill — syntactic sugar for browser sharing

Users remember /pair-agent, not $B pair-agent. The skill walks through
agent selection (OpenClaw, Hermes, Codex, Cursor, generic), local vs
remote setup, tunnel configuration, and includes platform-specific
notes for each agent type. Wraps the CLI command with context.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: remote browser access reference for paired agents

Full API reference, snapshot→@ref pattern, scopes, tab isolation,
error codes, ngrok setup, and same-machine shortcuts. The instruction
block points here for deeper reading.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: improved instruction block with snapshot→@ref pattern

The paste-into-agent instruction block now teaches the snapshot→@ref
workflow (the most powerful browsing pattern), shows the server URL
prominently, and uses clearer formatting. Tests updated to match.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: smart ngrok detection + auto-tunnel in pair-agent

The pair-agent command now checks ngrok's native config (not just
~/.gstack/ngrok.env) and auto-starts the tunnel when ngrok is
available. The skill template walks users through ngrok install
and auth if not set up, instead of just printing a dead localhost
URL.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: on-demand tunnel start via POST /tunnel/start

pair-agent now auto-starts the ngrok tunnel without restarting the
server. New POST /tunnel/start endpoint reads authtoken from env,
~/.gstack/ngrok.env, or ngrok's native config. CLI detects ngrok
availability and calls the endpoint automatically. Zero manual steps
when ngrok is installed and authed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: pair-agent skill must output the instruction block verbatim

Added CRITICAL instruction: the agent MUST output the full instruction
block so the user can copy it. Previously the agent could summarize
over it, leaving the user with nothing to paste.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: scoped tokens rejected on /command — auth gate ordering bug

The blanket validateAuth() gate (root-only) sat above the /command
endpoint, rejecting all scoped tokens with 401 before they reached
getTokenInfo(). Moved /command above the gate so both root and
scoped tokens are accepted. This was the bug Wintermute hit.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: pair-agent auto-launches headed mode before pairing

When pair-agent detects headless mode, it auto-switches to headed
(visible Chromium window) so the user can watch what the remote
agent does. Use --headless to skip this. Fixed compiled binary
path resolution (process.execPath, not process.argv[1] which is
virtual /$bunfs/ in Bun compiled binaries).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: comprehensive tests for auth ordering, tunnel, ngrok, headed mode

16 new tests covering:
- /command sits above blanket auth gate (Wintermute bug)
- /command uses getTokenInfo not validateAuth
- /tunnel/start requires root, checks native ngrok config, returns already_active
- /pair creates setup keys not session tokens
- Tab ownership checked before command dispatch
- Activity events include clientId
- Instruction block teaches snapshot→@ref pattern
- pair-agent auto-headed mode, process.execPath, --headless skip
- isNgrokAvailable checks all 3 sources (gstack env, env var, native config)
- handlePairAgent calls /tunnel/start not server restart

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: chain scope bypass + /health info leak when tunneled

1. Chain command now pre-validates ALL subcommand scopes before
   executing any. A read+meta token can no longer escalate to
   admin via chain (eval, js, cookies were dispatched without
   scope checks). tokenInfo flows through handleMetaCommand into
   the chain handler. Rejects entire chain if any subcommand fails.

2. /health strips sensitive fields (currentUrl, agent.currentMessage,
   session) when tunnel is active. Only operational metadata (status,
   mode, uptime, tabs) exposed to the internet. Previously anyone
   reaching the ngrok URL could surveil browsing activity.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: tout /pair-agent as headline feature in CHANGELOG + README

Lead with what it does for the user: type /pair-agent, paste into
your other agent, done. First time AI agents from different companies
can coordinate through a shared browser with real security boundaries.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: expand /pair-agent, /design-shotgun, /design-html in README

Each skill gets a real narrative paragraph explaining the workflow,
not just a table cell. design-shotgun: visual exploration with taste
memory. design-html: production HTML with Pretext computed layout.
pair-agent: cross-vendor AI agent coordination through shared browser.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: split handleCommand into handleCommandInternal + HTTP wrapper

Chain subcommands now route through handleCommandInternal for full security
enforcement (scope, domain, tab ownership, rate limiting, content wrapping).
Adds recursion guard for nested chains, rate-limit exemption for chain
subcommands, and activity event suppression (1 event per chain, not per sub).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add content-security.ts with datamarking, envelope, and filter hooks

Four-layer prompt injection defense for pair-agent browser sharing:
- Datamarking: session-scoped watermark for text exfiltration detection
- Content envelope: trust boundary wrapping with ZWSP marker escaping
- Content filter hooks: extensible filter pipeline with warn/block modes
- Built-in URL blocklist: requestbin, pipedream, webhook.site, etc.

BROWSE_CONTENT_FILTER env var controls mode: off|warn|block (default: warn)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: centralize content wrapping in handleCommandInternal response path

Single wrapping location replaces fragmented per-handler wrapping:
- Scoped tokens: content filters + datamarking + enhanced envelope
- Root tokens: existing basic wrapping (backward compat)
- Chain subcommands exempt from top-level wrapping (wrapped individually)
- Adds 'attrs' to PAGE_CONTENT_COMMANDS (ARIA value exposure defense)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: hidden element stripping for scoped token text extraction

Detects CSS-hidden elements (opacity, font-size, off-screen, same-color,
clip-path) and ARIA label injection patterns. Marks elements with
data-gstack-hidden, extracts text from a clean clone (no DOM mutation),
then removes markers. Only active for scoped tokens on text command.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: snapshot split output format for scoped tokens

Scoped tokens get a split snapshot: trusted @refs section (for click/fill)
separated from untrusted web content in an envelope. Ref names truncated
to 50 chars in trusted section. Root tokens unchanged (backward compat).
Resume command also uses split format for scoped tokens.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add SECURITY section to pair-agent instruction block

Instructs remote agents to treat content inside untrusted envelopes
as potentially malicious. Lists common injection phrases to watch for.
Directs agents to only use @refs from the trusted INTERACTIVE ELEMENTS
section, not from page content.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: add 4 prompt injection test fixtures

- injection-visible.html: visible injection in product review text
- injection-hidden.html: 7 CSS hiding techniques + ARIA injection + false positive
- injection-social.html: social engineering in legitimate-looking content
- injection-combined.html: all attack types + envelope escape attempt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: comprehensive content security tests (47 tests)

Covers all 4 defense layers:
- Datamarking: marker format, session consistency, text-only application
- Content envelope: wrapping, ZWSP marker escaping, filter warnings
- Content filter hooks: URL blocklist, custom filters, warn/block modes
- Instruction block: SECURITY section content, ordering, generation
- Centralized wrapping: source-level verification of integration
- Chain security: recursion guard, rate-limit exemption, activity suppression
- Hidden element stripping: 7 CSS techniques, ARIA injection, false positives
- Snapshot split format: scoped vs root output, resume integration

Also fixes: visibility:hidden detection, case-insensitive ARIA pattern matching.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: pair-agent skill compliance + fix all 16 pre-existing test failures

Root cause: pair-agent was added without completing the gen-skill-docs
compliance checklist. All 16 failures traced back to this.

Fixes:
- Sync package.json version to VERSION (0.15.9.0)
- Add "(gstack)" to pair-agent description for discoverability
- Add pair-agent to Codex path exception (legitimately documents ~/.codex/)
- Add CLI_COMMANDS (status, pair-agent, tunnel) to skill parser allowlist
- Regenerate SKILL.md for all hosts (claude, codex, factory, kiro, etc.)
- Update golden file baselines for ship skill
- Fix relink tests: pass GSTACK_INSTALL_DIR to auto-relink calls so they
  use the fast mock install instead of scanning real ~/.claude/skills/gstack

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: bump version and changelog (v0.15.12.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: E2E exit reason precedence + worktree prune race condition

Two fixes for E2E test reliability:

1. session-runner.ts: error_max_turns was misclassified as error_api
   because is_error flag was checked before subtype. Now known subtypes
   like error_max_turns are preserved even when is_error is set. The
   is_error override only applies when subtype=success (API failure).

2. worktree.ts: pruneStale() now skips worktrees < 1 hour old to avoid
   deleting worktrees from concurrent test runs still in progress.
   Previously any second test execution would kill the first's worktrees.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: restore token in /health for localhost extension auth

The CSO security fix stripped the token from /health to prevent leaking
when tunneled. But the extension needs it to authenticate on localhost.
Now returns token only when not tunneled (safe: localhost-only path).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: verify /health token is localhost-only, never served through tunnel

Updated tests to match the restored token behavior:
- Test 1: token assignment exists AND is inside the !tunnelActive guard
- Test 1b: tunnel branch (else block) does not contain AUTH_TOKEN

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: add security rationale for token in /health on localhost

Explains why this is an accepted risk (no escalation over file-based
token access), CORS protection, and tunnel guard. Prevents future
CSO scans from stripping it without providing an alternative auth path.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: verify tunnel is alive before returning URL to pair-agent

Root cause: when ngrok dies externally (pkill, crash, timeout), the server
still reports tunnelActive=true with a dead URL. pair-agent prints an
instruction block pointing at a dead tunnel. The remote agent gets
"endpoint offline" and the user has to manually restart everything.

Three-layer fix:
- Server /pair endpoint: probes tunnel URL before returning it. If dead,
  resets tunnelActive/tunnelUrl and returns null (triggers CLI restart).
- Server /tunnel/start: probes cached tunnel before returning already_active.
  If dead, falls through to restart ngrok automatically.
- CLI pair-agent: double-checks tunnel URL from server before printing
  instruction block. Falls through to auto-start on failure.

4 regression tests verify all three probe points + CLI verification.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add POST /batch endpoint for multi-command batching

Remote agents controlling GStack Browser through a tunnel pay 2-5s of
latency per HTTP round-trip. A typical "navigate and read" takes 4
sequential commands = 10-20 seconds. The /batch endpoint collapses N
commands into a single HTTP round-trip, cutting a 20-tab crawl from
~60s to ~5s.

Sequential execution through the full security pipeline (scope, domain,
tab ownership, content wrapping). Rate limiting counts the batch as 1
request. Activity events emitted at batch level, not per-command.
Max 50 commands per batch. Nested batches rejected.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test: add source-level security tests for /batch endpoint

8 tests verifying: auth gate placement, scoped token support, max
command limit, nested batch rejection, rate limiting bypass, batch-level
activity events, command field validation, and tabId passthrough.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: correct CHANGELOG date from 2026-04-06 to 2026-04-05

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: consolidate Hermes into generic HTTP option in pair-agent

Hermes doesn't have a host-specific config — it uses the same generic
curl instructions as any other agent. Removing the dedicated option
simplifies the menu and eliminates a misleading distinction.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: bump VERSION to 0.15.14.0, add CHANGELOG entry for batch endpoint

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate pair-agent/SKILL.md after main merge

Vendoring deprecation section from main's template wasn't reflected
in the generated file. Fixes check-freshness CI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* refactor: checkTabAccess uses options object, add own-only tab policy

Refactors checkTabAccess(tabId, clientId, isWrite) to use an options
object { isWrite?, ownOnly? }. Adds tabPolicy === 'own-only' support
in the server command dispatch — scoped tokens with this policy are
restricted to their own tabs for all commands, not just writes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add --domain flag to pair-agent CLI for domain restrictions

Allows passing --domain to pair-agent to restrict the remote agent's
navigation to specific domains (comma-separated).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* revert: remove batch commands CHANGELOG entry and VERSION bump

The batch endpoint work belongs on the browser-batch-multitab branch
(port-louis), not this branch. Reverting VERSION to 0.15.14.0.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: adopt main's headed-mode /health token serving

Our merge kept the old !tunnelActive guard which conflicted with
main's security-audit-r2 tests that require no currentUrl/currentMessage
in /health. Adopts main's approach: serve token conditionally based on
headed mode or chrome-extension origin. Updates server-auth tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: improve snapshot flags docs completeness for LLM judge

Adds $B placeholder explanation, explicit syntax line, and detailed
flag behavior (-d depth values, -s CSS selector syntax, -D unified
diff format and baseline persistence, -a screenshot vs text output
relationship). Fixes snapshot flags reference LLM eval scoring
completeness < 4.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-06 14:41:06 -07:00