Harden diagnostic response redaction

Redact every diagnostic response at the agent boundary, fail closed when sanitization cannot complete, and remove Windows, UNC, and slash-UNC paths from returned data. Preserve benign text while removing complete configured secret values, including nested JSON escapes and quoted HTML credential fields. Add focused regression coverage for collector errors, successful responses, support bundles, path variants, and punctuation secrets.

tests/diagnostics-agent.test.js

@@ -1,6 +1,7 @@
 const { test } = require('node:test');
 const assert = require('node:assert');
 const { createAgent } = require('../lib/diagnostics-agent');
+const { valueScrub } = require('../lib/support-bundle');
 
 function stubCollectors() {
   const calls = [];
@@ -28,6 +29,9 @@ test('agent rejects unknown ops and any write/exec-shaped op', () => {
     assert.equal(r.ok, false, `${bad} must be rejected`);
     assert.match(r.error, /unknown or non-readonly/);
   }
+  const pathShaped = agent.handle('C:\\Users\\PrivateProfile\\operation', {});
+  assert.ok(!pathShaped.error.includes('PrivateProfile'));
+  assert.match(pathShaped.error, /<redacted-path>/);
 });
 
 test('agent rejects inherited Object.prototype members (no whitelist bypass via the prototype chain)', () => {
@@ -53,10 +57,43 @@ test('agent maps each whitelisted op to its collector and is read-only only', ()
   for (const op of agent.ops) assert.ok(!/write|delete|set_|exec|restart|cancel|retry/.test(op), `${op} must be read-only`);
 });
 
-test('agent surfaces a collector ok:false verbatim and never throws', () => {
-  const agent = createAgent({ readLog: () => ({ ok: false, error: 'unknown or non-readable log: x' }), getSystemInfo: () => { throw new Error('boom'); } });
+test('agent redacts collector failures and thrown errors at the response boundary', () => {
+  const drivePath = 'C:\\Users\\PrivateProfile\\secret.log';
+  const uncPath = '\\\\?\\UNC\\private-server\\secret-share\\secret.log';
+  const agent = createAgent({
+    readLog: () => ({ ok: false, error: `cannot read ${drivePath}` }),
+    getSystemInfo: () => { throw new Error(`boom at ${uncPath}`); }
+  });
   assert.equal(agent.handle('read_log', { name: 'x' }).ok, false);
+  assert.ok(!JSON.stringify(agent.handle('read_log', { name: 'x' })).includes('PrivateProfile'));
   const thrown = agent.handle('get_system_info', {});
   assert.equal(thrown.ok, false);
   assert.match(thrown.error, /boom/);
+  assert.ok(!thrown.error.includes('private-server'));
+  assert.match(thrown.error, /<redacted-path>/);
+});
+
+test('agent redacts every successful response with configured secrets at the boundary', () => {
+  const secret = 'configured-secret-123';
+  const slashUnc = '//private-server/secret-share/secret.log';
+  const collectors = stubCollectors();
+  collectors.getSystemInfo = () => ({ nested: { message: `token ${secret}`, path: slashUnc } });
+  collectors.redactResponse = value => valueScrub(value, [secret]);
+  const result = createAgent(collectors).handle('get_system_info', {});
+  const json = JSON.stringify(result);
+  assert.equal(result.ok, true);
+  assert.ok(!json.includes(secret));
+  assert.ok(!json.includes('private-server'));
+  assert.match(json, /<redacted>/);
+  assert.match(json, /<redacted-path>/);
+});
+
+test('agent fails closed when response redaction fails', () => {
+  const agent = createAgent({
+    getSystemInfo: () => ({ token: 'must-not-leak' }),
+    redactResponse: () => { throw new Error('redactor unavailable'); }
+  });
+  const result = agent.handle('get_system_info', {});
+  assert.deepEqual(result, { ok: false, error: 'diagnostic response could not be safely returned' });
+  assert.ok(!JSON.stringify(result).includes('must-not-leak'));
 });

tests/diagnostics-collectors.test.js

@@ -6,7 +6,6 @@ const path = require('path');
 const support = require('../lib/support-bundle');
 const stats = require('../lib/stats');
 const { createCollectors } = require('../lib/diagnostics-collectors');
-const { createAgent } = require('../lib/diagnostics-agent');
 
 function makeFixture() {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'mhu-diag-'));
@@ -192,3 +191,18 @@ test('serverHealth assembles the one-shot hub without leaking secrets', () => {
   assert.ok(!json.includes('HUNTER2SECRET') && !json.includes('SECRETTOKEN123456') && !json.includes('WBHOOKSECRETTOKEN'), 'no secret leaks in server_health');
   assert.ok(!json.includes(dir) && !json.includes(paths.debug), 'server_health must not expose absolute log paths');
 });
+
+test('redactResponse scrubs configured secrets and absolute paths from arbitrary nested output', () => {
+  const { collectors, fixtureAlpha } = makeFixture();
+  const value = {
+    error: `token ${fixtureAlpha} at C:\\Users\\PrivateProfile\\secret.log`,
+    nested: [{ source: '\\\\?\\UNC\\private-server\\secret-share\\secret.log' }]
+  };
+  const out = collectors.redactResponse(value);
+  const json = JSON.stringify(out);
+  assert.ok(!json.includes(fixtureAlpha));
+  assert.ok(!json.includes('PrivateProfile'));
+  assert.ok(!json.includes('private-server'));
+  assert.match(json, /<redacted>/);
+  assert.match(json, /<redacted-path>/);
+});

tests/support-bundle.test.js

@@ -117,6 +117,42 @@ test('redactLogText masks a one-character configured secret only as a complete s
   assert.ok(out.includes(`marker=${REDACTED}`));
 });
 
+test('redactLogText replaces configured secrets only as complete values', () => {
+  const out = redactLogText([
+    'password=orange',
+    'configured token orange accepted',
+    'file=orangejuice',
+    'file=orange.mkv',
+    'password=.',
+    'version=2.1.20',
+    'sentence finished.'
+  ].join('\n'), ['orange', '.']);
+  assert.ok(!out.includes('password=orange'));
+  assert.ok(!out.includes('token orange'));
+  assert.ok(!out.includes('password=.'));
+  assert.ok(out.includes('file=orangejuice'));
+  assert.ok(out.includes('file=orange.mkv'));
+  assert.ok(out.includes('version=2.1.20'));
+  assert.ok(out.includes('sentence finished.'));
+});
+
+test('redactLogText removes JSON-escaped configured secrets and quoted HTML credential values', () => {
+  const jsonSecret = 'alpha"beta\\gamma';
+  const password = 'abc>secret';
+  const token = 'token>quoted';
+  const input = [
+    JSON.stringify({ note: jsonSecret, token: jsonSecret }),
+    `<input type="password" value="${password}">`,
+    `<input value='${token}' name='api_token' type='text'>`
+  ].join('\n');
+  const out = redactLogText(input, [jsonSecret]);
+  assert.ok(!out.includes(jsonSecret));
+  assert.ok(!out.includes('alpha\\"beta\\\\gamma'));
+  assert.ok(!out.includes(password));
+  assert.ok(!out.includes(token));
+  assert.ok((out.match(/<redacted>/g) || []).length >= 3);
+});
+
 test('redactLogText removes complete local paths from structured and free-form log text', () => {
   const profilePath = ['C:', 'Users', 'ProfileFixture', 'Private Folder', 'episode.mkv'].join('\\');
   const drivePath = ['D:', 'Archive', 'Private Folder', 'source.mkv'].join('\\');
@@ -135,6 +171,23 @@ test('redactLogText removes complete local paths from structured and free-form l
   assert.ok((out.match(/<redacted-path>/g) || []).length >= 4);
 });
 
+test('redactLogText removes extended UNC, extended drive, UNC and slash-UNC paths', () => {
+  const extendedUnc = '\\\\?\\UNC\\private-server\\secret-share\\hidden.log';
+  const extendedDrive = '\\\\?\\C:\\Users\\PrivateProfile\\hidden.log';
+  const unc = '\\\\private-server\\secret-share\\hidden.log';
+  const slashUnc = '//private-server/secret-share/hidden.log';
+  const out = redactLogText([
+    `extended UNC failure: ${extendedUnc}`,
+    `extended drive failure: ${extendedDrive}`,
+    `UNC failure: ${unc}`,
+    `slash UNC failure: ${slashUnc}`
+  ].join('\n'), []);
+  for (const fragment of ['private-server', 'secret-share', 'PrivateProfile', 'hidden.log']) {
+    assert.ok(!out.includes(fragment), `private path fragment survived: ${fragment}`);
+  }
+  assert.equal((out.match(/<redacted-path>/g) || []).length, 4);
+});
+
 test('sanitizeConfig does not mutate input', () => {
   const input = { hosters: { 'voe.sx': [{ password: 'secret' }] } };
   const clone = JSON.parse(JSON.stringify(input));
@@ -285,3 +338,32 @@ test('buildSupportBundleText removes a one-character configured secret', () => {
     fs.unlinkSync(tmp);
   }
 });
+
+test('buildSupportBundleText contains no escaped secrets, credential HTML or absolute path variants', () => {
+  const tmp = path.join(os.tmpdir(), `mhu-bundle-hard-redaction-${Date.now()}.log`);
+  const secret = 'alpha"beta\\gamma';
+  const paths = [
+    '\\\\?\\UNC\\private-server\\secret-share\\hidden.log',
+    '\\\\private-server\\secret-share\\hidden.log',
+    '//private-server/secret-share/hidden.log',
+    'C:\\Users\\PrivateProfile\\hidden.log'
+  ];
+  fs.writeFileSync(tmp, [
+    JSON.stringify({ token: secret, path: paths[0] }),
+    '<input type="password" value="abc>secret">',
+    ...paths
+  ].join('\n'));
+  try {
+    const text = buildSupportBundleText({
+      header: { Source: paths[3] },
+      sanitizedConfig: { marker: JSON.stringify(secret), path: paths[1] },
+      secrets: [secret],
+      files: [{ label: paths[2], path: tmp }]
+    });
+    for (const value of ['alpha', 'beta', 'gamma', 'abc>secret', 'private-server', 'secret-share', 'PrivateProfile', 'hidden.log', tmp]) {
+      assert.ok(!text.includes(value), `support bundle leak survived: ${value}`);
+    }
+  } finally {
+    fs.unlinkSync(tmp);
+  }
+});