New stealth.ts export that turns the GSTACK_* env vars (already populated
by gbrowser's gbd from host_profile.go) into the --gstack-* cmdline
switches the Pack 1 Chromium patches read at WebGL getParameter,
NavigatorUA::userAgentData, NavigatorConcurrentHardware::hardwareConcurrency,
and NavigatorDeviceMemory::deviceMemory time.
Wired into all three launchArgs sites: launch() (headless), launchHeaded()
(real product path), and handoff() (headless → headed re-launch).
Mapping:
GSTACK_GPU_VENDOR → --gstack-gpu-vendor
GSTACK_GPU_RENDERER → --gstack-gpu-renderer
GSTACK_PLATFORM → --gstack-ua-platform (with mapping:
MacARM/MacIntel → macOS, Win32 → Windows,
Linux x86_64 → Linux)
GSTACK_GPU_CHIPSET → --gstack-ua-model
GSTACK_HW_CONCURRENCY → --gstack-hw-concurrency
GSTACK_DEVICE_MEMORY → --gstack-device-memory
Each switch is emitted only when its env var is non-empty — empty
values fall through to the patch's "no override" path, which returns
the real Chromium native value. Safe to ship on Chromium builds
without the Pack 1 patches applied (zero behavior change).
The patches themselves live in the gbrowser repo at chromium/patches/
{webgl-vendor-spoof,ua-client-hints-stealth,worker-navigator-stealth}.patch.
Both halves (gstack arg construction + gbrowser C++ patches) must
land + Chromium rebuild before the spoof reaches the WebGL/UA-CH/
hardware accessors. Currently dormant until then.
Tests (browse/test/stealth-layer-c.test.ts):
7 new buildGStackLaunchArgs cases — empty env, all-populated, partial,
platform mapping (MacARM/MacIntel/Win32/Linux), unrecognized platform
fallthrough, vendor-with-spaces escape-safety.
All 32 stealth/browser-manager tests pass.
For GBrowser specifically: gstack-side half of the Pack 1 flag plumbing.
gbrowser repo will bump the submodule pointer to this commit, then re-run
bun run test/anti-bot/evidence-run.ts to verify creepjs's "33% headless"
score drops after Pack 1 + Chromium rebuild.
Garry Tan
13f7e351da