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<!DOCTYPE html>
<meta charset="utf-8">
<title>WebGL Vendor FPP precedence - added WebGLVendorConstant does not override an enabled WebGLVendorRandomize</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<script>
/* global SimpleTest SpecialPowers */
SimpleTest.waitForExplicitFinish();
// RFPTarget enum values, from
// toolkit/components/resistfingerprinting/RFPTargets.inc. The precedence is
// "Randomize overrides Constant overrides Sanitize".
const RFPTarget = {
WebGLVendorRandomize: 79,
};
// Whether a given RFPTarget is in the currently-enabled fingerprinting
// protection set (compiled defaults plus the overrides pref). Evaluated in the
// parent process and returned as a plain boolean, so the test follows the
// actual configuration instead of assuming a particular build channel.
function isFPPTargetEnabled(target) {
return SpecialPowers.spawnChrome([target], t => {
let set = Services.rfp.enabledFingerprintingProtections;
let part = set.getNth32BitSet(t >>> 5);
return (part & (1 << (t & 31))) !== 0;
});
}
document.addEventListener("DOMContentLoaded", async function() {
// Additively enable WebGLVendorConstant on top of the defaults.
await SpecialPowers.pushPrefEnv({
set: [
["privacy.fingerprintingProtection", true],
["privacy.fingerprintingProtection.overrides", "+WebGLVendorConstant"],
["privacy.resistFingerprinting", false]
]
});
let canvas = document.body.appendChild(document.createElement("canvas"));
if (!canvas) {
SimpleTest.ok(false, "Cannot create canvas");
SimpleTest.finish();
return;
}
let gl = canvas.getContext("webgl");
if (!gl) {
SimpleTest.ok(false, "Cannot get WebGL context");
SimpleTest.finish();
return;
}
// Try to get the WEBGL_debug_renderer_info extension
let ext = gl.getExtension("WEBGL_debug_renderer_info");
if (!ext) {
SimpleTest.ok(false, "WEBGL_debug_renderer_info extension should be available with FPP");
SimpleTest.finish();
return;
}
let vendor = gl.getParameter(ext.UNMASKED_VENDOR_WEBGL);
if (await isFPPTargetEnabled(RFPTarget.WebGLVendorRandomize)) {
// The higher-precedence WebGLVendorRandomize is enabled, so it overrides
// the added WebGLVendorConstant and the vendor is randomized.
SimpleTest.isnot(vendor, "Mozilla",
"Added WebGLVendorConstant must not override the enabled WebGLVendorRandomize");
SimpleTest.ok(vendor.startsWith("Mozilla "),
"Vendor should be the randomized 'Mozilla <Base64>'. Got: " + vendor);
let base64Part = vendor.substring("Mozilla ".length);
SimpleTest.ok(/^[A-Za-z0-9+/=]+$/.test(base64Part),
"Randomized suffix should be Base64. Got: " + base64Part);
} else {
// WebGLVendorRandomize is not enabled, so the added WebGLVendorConstant is
// the highest-precedence vendor target and yields the constant "Mozilla".
SimpleTest.is(vendor, "Mozilla",
"WebGLVendorConstant should yield constant 'Mozilla'");
}
SimpleTest.finish();
});
</script>