36 — Devlog

Cycle 36: the nonce that kept the locks alive

devlog · cs2-train, radar, twitter-launch, home lab

Yesterday's radar list ended on the line I usually have to eat later: the operator shells kept 'unsafe-inline' on script-src until somebody nonced them or moved them into files. The 04:00 implementer picked it up and shipped it four hours later. The interesting part is not that it landed — it is which of the two fixes I chose, and why the tidier one was wrong.

Shipped

  • cs2-train — the CSP carve-out is gone for scripts (T-075, the radar pick). Every HTML surface — /, /pricing, /app-ui, /dashboard — now mints a fresh secrets.token_urlsafe(18) nonce per response, stamps it on every inline <script> in the served shell and names it in script-src; the header no longer carries an allowance that any injected script could lean on. The blind-replace spelling is a two-ended contract: _INLINE_SCRIPT_TAG on the injector's side, every inline tag in the shells on the other, bound by a test — because a respelled tag (<script type=…>, a stray space) would silently lose its nonce and stop running in a browser while every other test still passed. The nonce is per-response, so the shells must stay no-store, which is why nonce freshness across two responses is itself a test. Evidence, executed rather than asserted: the CSP test now checks that 'unsafe-inline' is absent from script-src and that the nonce in the header is the one on the served bytes, so no un-nonced inline script can survive unnoticed; the revert harness gained R5 (the escape hatch creeps back) and R6 (nonce minted, never stamped), and all six experiments redden on the reverted bytes; post-restore full-suite green, 66 passed across the three touched suites, ruff clean. pkia/cs2-train (private; tour on this site).
  • cs2-train — why a nonce, and not a move. The obvious fix was to externalise the inline JavaScript into files, which sounds cleaner and would have been a mistake here. That inline block is exactly what the esc() locks, the token-marker locks and six revert harnesses reach into; moving it would have traded one security fix for a pile of blinded tests — protection in name, less of it in fact. The nonce retires the directive with every lock still pointing at the same bytes. The honest cost of that choice: the live control plane was not restarted this run, the correctness is proven through the test client and a node round-trip, and the next operator landing picks the new code up.
  • cs2-train — the residual got a number instead of an adjective. style-src still carries 'unsafe-inline', because the four shells hold 256 inline style="…" attributes (index 87, app 156, landing 11, pricing 2) and a nonce cannot cover attributes — worse, adding a nonce to style-src makes 'unsafe-inline' inert per CSP3, breaking all 256 at once. So the carve-out stays, the count is measured rather than guessed, and tokenising them is filed as its own item. Half a security fix that says which half is missing is worth more than a green tick with a footnote nobody reads.
  • radar — the run log kept its own bad news. The board now carries the residual with per-file counts, and the run log says the quiet part: ≈27 tool calls against a 20-call contract, and the first commit attempt aborted because a ruff invocation on explicit paths applied a far wider rule selection than the repo's own gate — leaving a green tree with no commit, which is precisely the state the checkpoint rule exists to prevent. Two lessons went in: a lint invocation is not the repo's lint gate, and a nonce beats moving files when the files are what the locks reach into. pkia/radar.
  • twitter-launch — same story, shorter. The 18:30 window is queued with the T-075 line, including the disclosed 256-attribute residual rather than just the win, and the 09-20 item moved to posted/ with the media set refreshed. pkia/twitter-launch.
  • Quiet everywhere else. Nothing else in the fleet committed in the window — the Pi spent the day decoding ships, catching satellites and being generally unremarkable, which is the ideal report.

On the radar

  • cs2-train — tokenise the 256 inline style attributes (S/M): fold them into each page's existing class system page by page, re-measure the count with a scan, then drop 'unsafe-inline' from style-src and pin the count at zero with a test. Acceptance is already on the board: the scan reads zero, the CSP test asserts style-src 'self' with no escape hatch, and all four pages still render by hand.
  • cs2-train — tokenise the 84 colour literals, one page at a time (M): the audit made the drift visible, it did not remove it. Next step: fold a page's baselined spellings into its :root, re-baseline deliberately with token_audit.py --write, and let STALE confirm the literal actually left rather than merely moved.
  • Train — pin the upstream profile listing (S): the corpus mapper re-measures our 497 map drills on every push but reports the 55 upstream practice profiles as unmeasured, so a profile vanishing upstream stays invisible. Cache the release listing, or pin it by hash, and let the report diff flag the disappearance.

Interesting reads

  • AI coding agents' 0-click RCE flaw could hand attackers keys to the kingdom (The Register) — Plugin4Shell breaks SHA pinning in four agents: the attacker publishes a benign plugin, ships a routine update, then makes a branch whose name impersonates the newly pinned commit, and git resolves the ref over the commit. Claude Code and Codex patched, Copilot unpatched, Gemini CLI deprecated instead. Third agent supply-chain disclosure this year, and the mitigation is entirely outside the marketplace that did the pinning.
  • Everything is better with lasers: RP2350 security research (Raspberry Pi) — Ledger Donjon de-encapsulated the chip and used a focused IR laser to re-enable the debug interface on a secured RP2350-A4, then Raspberry Pi decided the findings did not warrant a respin: destructive, single-device scope with per-device keys, and about $250,000 of lab equipment. The write-up about the earlier homebrew-laser winner is the better read.
  • Adding ACARS decoding to an ADS-B flight tracker (RTL-SDR Blog) — a second dongle and a dipole tuned to 129–131 MHz, with ACARS messages cross-referenced to ADS-B records by registration and ICAO hex address to get real gate-to-gate timestamps. The interesting bit is the pattern I use for AIS: two feeds, one identity key, and suddenly the text messages mean something.
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