release: prepare v4.8.5 security hardening release

tests/file-transfer-consent.test.mjs

@@ -0,0 +1,62 @@
+import assert from 'node:assert/strict';
+import { EnhancedSecureFileTransfer } from '../src/transfer/EnhancedSecureFileTransfer.js';
+
+function createSystem(onIncomingFileRequest = () => {}) {
+    const manager = {
+        dataChannel: { onmessage: null, send() {}, readyState: 'open' },
+        isVerified: true,
+        fileTransferSystem: null,
+        isConnected: () => true
+    };
+    const system = new EnhancedSecureFileTransfer(manager, null, null, null, null, onIncomingFileRequest);
+    system.sendSecureMessage = async () => {};
+    return system;
+}
+
+function validMetadata(overrides = {}) {
+    return {
+        type: 'file_transfer_start',
+        fileId: 'file_1',
+        fileName: 'report.pdf',
+        fileSize: 1024,
+        fileType: 'application/pdf',
+        fileHash: 'abc',
+        totalChunks: 1,
+        chunkSize: 1024,
+        salt: new Array(32).fill(1),
+        ...overrides
+    };
+}
+
+// Metadata is validated before a consent prompt is shown.
+{
+    const system = createSystem();
+    assert.equal(system.validateIncomingMetadata(validMetadata()).isValid, true);
+    assert.equal(system.validateIncomingMetadata(validMetadata({ fileName: '../evil.pdf' })).isValid, false);
+    assert.equal(system.validateIncomingMetadata(validMetadata({ fileSize: 200 * 1024 * 1024 })).isValid, false);
+}
+
+// No receiving state or chunk buffers are allocated before explicit acceptance.
+{
+    let prompted = null;
+    const system = createSystem(request => { prompted = request; });
+    await system.handleFileTransferStart(validMetadata());
+    assert.equal(prompted.fileName, 'report.pdf');
+    assert.equal(system.pendingIncomingTransfers.size, 1);
+    assert.equal(system.receivingTransfers.size, 0);
+
+    await system.handleFileChunk({ fileId: 'file_1', chunkIndex: 0 });
+    assert.equal(system.pendingChunks.size, 0);
+}
+
+// Incoming request spam is bounded.
+{
+    const system = createSystem();
+    for (let index = 0; index < system.MAX_PENDING_INCOMING_TRANSFERS; index += 1) {
+        await system.handleFileTransferStart(validMetadata({ fileId: `file_${index}` }));
+    }
+    await system.handleFileTransferStart(validMetadata({ fileId: 'file_overflow' }));
+    assert.equal(system.pendingIncomingTransfers.size, system.MAX_PENDING_INCOMING_TRANSFERS);
+}
+
+console.log('File transfer consent tests passed');