fix: TUI hardening — non-loopback LAN gate + assert cc_entrypoint (#115)#122
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Two TUI-mode findings from the 2026-05-31 audit (ADR 0007):
1. The fail-loud LAN gate refused TUI boot only when CLAUDE_BIND === "0.0.0.0",
but binding to a concrete LAN IP, a Tailscale 100.x address, or IPv6 :: is
equally network-exposed and slipped through — letting any reachable peer drive
the operator's full-filesystem claude session. New isLoopbackBind() treats only
127.0.0.0/8 / ::1 / localhost / ::ffff:127.0.0.1 as safe; the gate now trips on
any non-loopback bind (OCP_TUI_ALLOW_LAN=1 escape hatch retained).
2. verifyEntrypoint() was implemented and unit-tested but never wired: readTuiTranscript
discarded the events and returned only text, so a silent degrade to the metered
sdk-cli (Agent SDK) billing pool — which still returns text but costs money — went
undetected. readTuiTranscript now returns { text, entrypoint }; runTuiTurn passes it
through; callClaudeTui logs a "tui_entrypoint_mismatch" warning when configured cli
mode yields a non-cli entrypoint (including null/unverified). callClaudeTui still
returns Promise<string>, so singleflight/cache/completion downstream is unchanged.
ALIGNMENT.md: TUI is a proxy-side execution-mode bridge (ADR 0007); this adds a local
bind classifier (startup gate) + a non-fatal log assertion of an existing classification
— no Anthropic operation forwarded, so a cli.js citation is N/A under Rule 2. No
blacklisted tokens or port literals introduced; alignment.yml passes.
Independent fresh-context reviewer (opus): APPROVE WITH MINOR (Iron Rule 10) — verified
isLoopbackBind via truth table (no exposed address misclassified as loopback — the
dangerous direction), the full string→{text,entrypoint} contract ripple across all
callers (Promise<string> preserved), the mismatch logic (warns on sdk-cli AND null in
cli mode, silent for auto/off, non-fatal), and ALIGNMENT N/A via a fetch/header grep.
Minors are process-only (this commit body; a future lib/ extraction of the test-mirrored
helper). npm test → 181 passed, 0 failed.
Closes #115.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
Fixes the two TUI-mode hardening findings from the 2026-05-31 audit (#115, P2; ADR 0007).
0.0.0.0; a concrete LAN IP / Tailscale100.x/ IPv6::slipped through (any reachable peer could drive the operator's full-filesystem claude session). NewisLoopbackBind()treats only127.0.0.0/8/::1/localhost/::ffff:127.0.0.1as safe; the gate now trips on any non-loopback bind.OCP_TUI_ALLOW_LAN=1escape hatch retained.cc_entrypoint—verifyEntrypoint()was implemented + unit-tested but never wired;readTuiTranscriptdiscarded the events, so a silent degrade to the meteredsdk-clipool (still returns text, but costs money) went undetected.readTuiTranscriptnow returns{ text, entrypoint };runTuiTurnpasses it through;callClaudeTuilogstui_entrypoint_mismatchwhen configuredclimode yields a non-clientrypoint (incl.null/unverified).callClaudeTuistill returnsPromise<string>→ downstream unchanged.ALIGNMENT.md
alignment.ymlpasses.isLoopbackBindvia truth table (no exposed address misclassified as loopback — the dangerous direction is sound; default127.0.0.1still boots), the fullstring→{text,entrypoint}contract ripple across every caller (grepped;Promise<string>preserved for singleflight/cache/completion), the mismatch logic (warns onsdk-cliANDnullinclimode, silent forauto/off, non-fatal), and ALIGNMENT N/A via a fetch/header grep.npm test→ 181 passed, 0 failed. Verdict APPROVE WITH MINOR (process-only minors).Closes #115.
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