security: mkdtempSync for all scratch dirs (fixes 9 CodeQL insecure-temp-file alerts)#20
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…insecure-temporary-file) Every demo/test/MCP scratch path was built from a predictable name (os.tmpdir() + a fixed prefix + process.pid), which a local attacker can pre-create or symlink ahead of the write. Switch all of them to fs.mkdtempSync(path.join(os.tmpdir(), '<prefix>-')), which creates an unpredictable 0700 directory atomically. - demo.mjs, test/stack.test.mjs, demo/mcp-demo.mjs, test/mcp.test.mjs: HOME/KH now mkdtempSync; the redundant mkdirSync is dropped. - audit-trail.mjs runTrilogy(): default home is mkdtempSync; the explicit mkdirSync(home) stays so caller-supplied homes are still created. - test/audit.test.mjs: the four caller-supplied homes are mkdtempSync too, so the interprocedural write in runTrilogy has no predictable source. - mcp.mjs canon_scan: write the manifest into a mkdtempSync dir and rmSync the whole dir in finally; the predictable pid+hash filename (and the now unused hashStr helper) are removed. Also normalizes demo/mcp-demo.mjs and test/mcp.test.mjs, which used the same pattern but were not yet flagged, so the class can't resurface. Tests: 16/16 pass; demo.mjs and demo/mcp-demo.mjs run clean.
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What
All 9 open CodeQL
js/insecure-temporary-filealerts (#13–#21) share one root cause: scratch paths built from a predictable name —path.join(os.tmpdir(), '<prefix>-' + process.pid). A local attacker can pre-create or symlink that path before the write.This switches every such site to
fs.mkdtempSync(path.join(os.tmpdir(), '<prefix>-')), which atomically creates an unpredictable, 0700 directory.Changes
demo.mjsHOME→mkdtempSync; drop redundantmkdirSynctest/stack.test.mjsHOME→mkdtempSync; drop redundantmkdirSyncaudit-trail.mjsrunTrilogy()defaulthome→mkdtempSync(keepsmkdirSync(home)for caller-supplied homes)test/audit.test.mjsmkdtempSync, so the interprocedural write inrunTrilogyhas no predictable sourcemcp.mjsmkdtempSyncdir,rmSyncthe dir infinally; predictablepid+hashfilename and the now-deadhashStrhelper removedAlso normalizes
demo/mcp-demo.mjsandtest/mcp.test.mjs— same predictable pattern, not yet flagged — so the class can't resurface on the next scan.Verification
npm test→ 16/16 passnode demo.mjsandnode demo/mcp-demo.mjsrun cleanNo public API change; the composed gate's behavior is unchanged.