security: mkdtempSync for all scratch dirs (fixes 9 CodeQL insecure-temp-file alerts)

audit-trail.mjs

@@ -66,7 +66,7 @@ export function guardedCall({ manifest, name, action, leaseId, host, lock, polic
 // so the demo and the assertions exercise the EXACT same run. Sets up an isolated
 // strongroom vault + a clean (pinned) and a poisoned (never-pinned) tool, then drives
 // the four beats through the audited gate. Returns the trail + per-beat results.
-export function runTrilogy({ home = path.join(os.tmpdir(), 'oys-audit-' + process.pid) } = {}) {
+export function runTrilogy({ home = fs.mkdtempSync(path.join(os.tmpdir(), 'oys-audit-')) } = {}) {
   process.env.KEEPER_HOME = home;
   fs.mkdirSync(home, { recursive: true });
   const tmp = (n) => path.join(home, n);

demo.mjs

@@ -8,9 +8,8 @@ import { check } from '@askalf/redstamp';
 import { scan, pin, diff } from '@askalf/truecopy';
 import { addSecret, grant, redeem } from '@askalf/strongroom';
 
-const HOME = path.join(os.tmpdir(), 'ass-demo-' + process.pid);
+const HOME = fs.mkdtempSync(path.join(os.tmpdir(), 'ass-demo-'));
 process.env.KEEPER_HOME = HOME;
-fs.mkdirSync(HOME, { recursive: true });
 const tmp = (n) => path.join(HOME, n);
 const lock = tmp('truecopy.lock');
 const policy = { egressAllow: ['api.example.com'] };

demo/mcp-demo.mjs

@@ -8,9 +8,8 @@ import fs from 'node:fs';
 import path from 'node:path';
 
 // strongroom reads KEEPER_HOME lazily, so seeding a temp vault here is enough.
-const KH = path.join(os.tmpdir(), 'oys-mcp-demo-' + process.pid);
+const KH = fs.mkdtempSync(path.join(os.tmpdir(), 'oys-mcp-demo-'));
 process.env.KEEPER_HOME = KH;
-fs.mkdirSync(KH, { recursive: true });
 
 const { Client } = await import('@modelcontextprotocol/sdk/client/index.js');
 const { InMemoryTransport } = await import('@modelcontextprotocol/sdk/inMemory.js');

mcp.mjs

@@ -67,15 +67,16 @@ export function createOysServer(opts = {}) {
   }, async ({ manifest }) => {
     let parsed;
     try { parsed = JSON.parse(manifest); } catch (e) { return err(`manifest is not valid JSON: ${e.message}`); }
-    const tmp = path.join(os.tmpdir(), `oys-truecopy-${process.pid}-${Math.abs(hashStr(manifest))}.json`);
+    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'oys-truecopy-'));
+    const tmp = path.join(dir, 'manifest.json');
     try {
       fs.writeFileSync(tmp, JSON.stringify(parsed));
       const r = truecopyScan(tmp);
       return json({ verdict: r.verdict, findings: r.findings ?? r.flags ?? [], skill: r.skill?.name ?? null });
     } catch (e) {
       return err(`truecopy scan failed: ${e.message}`);
     } finally {
-      try { fs.unlinkSync(tmp); } catch { /* noop */ }
+      fs.rmSync(dir, { recursive: true, force: true });
     }
   });
 
@@ -103,10 +104,3 @@ export function createOysServer(opts = {}) {
 
   return { server };
 }
-
-/** Tiny stable string hash for temp filenames (not security-sensitive). */
-function hashStr(s) {
-  let h = 0;
-  for (let i = 0; i < s.length; i++) { h = (h << 5) - h + s.charCodeAt(i); h |= 0; }
-  return h;
-}

test/audit.test.mjs

@@ -16,7 +16,7 @@ import path from 'node:path';
 import { runTrilogy, verifyAuditFile, forgeEntry, findEntry, AuditLog } from '../audit-trail.mjs';
 
 test('the gate records every layer decision into one chain, in order', () => {
-  const { audit, results } = runTrilogy({ home: path.join(os.tmpdir(), 'oys-audit-order-' + process.pid) });
+  const { audit, results } = runTrilogy({ home: fs.mkdtempSync(path.join(os.tmpdir(), 'oys-audit-order-')) });
   // the four beats produced the expected verdicts (same as stack.test.mjs)
   assert.ok(results.proceed.ok, 'beat 0: clean call proceeds');
   assert.equal(results.truecopy.by, 'truecopy', 'beat 1: truecopy stops the poisoned tool');
@@ -32,7 +32,7 @@ test('the gate records every layer decision into one chain, in order', () => {
 });
 
 test('the untouched chain verifies, on disk', () => {
-  const { audit, trailPath } = runTrilogy({ home: path.join(os.tmpdir(), 'oys-audit-intact-' + process.pid) });
+  const { audit, trailPath } = runTrilogy({ home: fs.mkdtempSync(path.join(os.tmpdir(), 'oys-audit-intact-')) });
   // in-memory verify
   assert.equal(audit.verify(), true);
   // durable verify (the daemon-grade path)
@@ -43,7 +43,7 @@ test('the untouched chain verifies, on disk', () => {
 });
 
 test('editing a past verdict breaks verification and pinpoints the entry', () => {
-  const { audit, trailPath } = runTrilogy({ home: path.join(os.tmpdir(), 'oys-audit-edit-' + process.pid) });
+  const { audit, trailPath } = runTrilogy({ home: fs.mkdtempSync(path.join(os.tmpdir(), 'oys-audit-edit-')) });
   audit.flush(trailPath);
   assert.equal(verifyAuditFile(trailPath).ok, true);
 
@@ -58,7 +58,7 @@ test('editing a past verdict breaks verification and pinpoints the entry', () =>
 });
 
 test('deleting an entry (truncating the chain mid-log) is also caught', () => {
-  const { audit, trailPath } = runTrilogy({ home: path.join(os.tmpdir(), 'oys-audit-del-' + process.pid) });
+  const { audit, trailPath } = runTrilogy({ home: fs.mkdtempSync(path.join(os.tmpdir(), 'oys-audit-del-')) });
   audit.flush(trailPath);
   const lines = fs.readFileSync(trailPath, 'utf8').split('\n').filter((l) => l.trim());
   // drop a middle entry: the NEXT entry's `prev` no longer matches the new predecessor's hash

test/mcp.test.mjs

@@ -11,9 +11,8 @@ import path from 'node:path';
 
 // strongroom reads KEEPER_HOME lazily (at call time), so setting it here — after the
 // hoisted imports — is fine; seed a secret to lease.
-const KH = path.join(os.tmpdir(), 'oys-mcp-test-' + process.pid);
+const KH = fs.mkdtempSync(path.join(os.tmpdir(), 'oys-mcp-test-'));
 process.env.KEEPER_HOME = KH;
-fs.mkdirSync(KH, { recursive: true });
 
 import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js';

test/stack.test.mjs

@@ -12,9 +12,8 @@ import { check } from '@askalf/redstamp';
 import { scan, pin, diff } from '@askalf/truecopy';
 import { addSecret, grant, redeem } from '@askalf/strongroom';
 
-const HOME = path.join(os.tmpdir(), 'trifecta-' + process.pid);
+const HOME = fs.mkdtempSync(path.join(os.tmpdir(), 'trifecta-'));
 process.env.KEEPER_HOME = HOME;
-fs.mkdirSync(HOME, { recursive: true });
 const tmp = (n) => path.join(HOME, n);
 const lock = tmp('truecopy.lock');
 const policy = { egressAllow: ['api.example.com'] };