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orchestrator/agent-team/ci
Adam Moussa 8f28fbe6a5 Harden CI guard: symlink-escape reject, strict decode, scope canon; back with tests
Resolves the GPT-4.1 cross-review FIX items on the §3.3.2 CI apply/verify guard:
- Symlink-escape (Medium-High): reject any candidate diff that introduces a
  symlink (git mode 120000). A symlink can redirect a later in-diff write into a
  denied path that textual canonicalization cannot see; auto-built diffs have no
  legitimate symlinks, so this fails closed (exit 7).
- Diff-parse robustness (Medium): decode the diff as strict UTF-8 and fail closed
  (exit 8) instead of errors='replace', closing homoglyph/encoding evasion.
- Declared-scope canonicalization (Medium): drop parent-escaping scope globs so a
  malformed scope can only shrink coverage, never widen it past repo root.
- Egress allowlist (Low-Med): explicit DEPLOY marker to parameterize the
  build-test registries per target repo before enabling.

Backs the gate's correctness claim with a committed, runnable suite
(tests/test_ci_gate_workflow.py) that extracts the inline guard from the YAML and
exercises good + adversarial diffs (clean, hash mismatch, workflow delete,
copy-into-denied, symlink, non-UTF-8, out-of-scope, unscoped, escaping scope).
Corrects the README "Tests" section that claimed coverage that did not exist.
Full suite: 557 passed, 1 skipped; ruff clean.
2026-06-17 15:16:12 -04:00
..
agent-team-apply-verify.yml Harden CI guard: symlink-escape reject, strict decode, scope canon; back with tests 2026-06-17 15:16:12 -04:00
README.md Harden CI guard: symlink-escape reject, strict decode, scope canon; back with tests 2026-06-17 15:16:12 -04:00

agent-team/ci — split-job CI apply/verify workflow (Plane-2 leaf)

Pre-deployment scaffolding for the R720 agent-team SDLC pipeline. This directory holds the split-job CI apply/verify workflow that turns a builder agent's untrusted candidate diff into a verified draft PR — the §3.3.2 trust boundary, Phase P3 (§7.1) of ../../docs/r720-agent-team-design.md.

STATUS: DEPLOY-GATED. NOT ENABLED, NOT PROVISIONED. This is authored as files only. Per the design (§3.3.2, §7.1 P3) the workflow + its OIDC role must clear BOTH /sh-security-review AND the mandatory GPT-4.1 cross-review before deployment, because it is IaC/IAM + untrusted-input handling. The privileged draft-PR step is hard-disabled (if: ${{ false }}) and the OIDC id-token/pull-requests: write grants are left commented until those gates pass. Nothing here is wired to a live org repo.

Files

File What it is
agent-team-apply-verify.yml The split-job workflow. Self-contained: the load-bearing gate logic (diff integrity, trust-control denylist, declared-scope check, pure-code pass/fail) is embedded inline as stdlib-only, type-hinted Python heredocs, so the workflow has no external script dependency.
README.md This file.

The filename is kebab-case per the handbook. Deployment target (later, after the gates): promote into Sea-Haven-Industries/.github as a reusable workflow (engineering-handbook/cicd.md); the Option-B OIDC apply path invokes it.

The trust boundary (design §3.3.2)

The builder agents are semi-trusted: an LLM that read repo content can be wrong or prompt-injected, so the candidate diff is treated as untrusted code. The threat is that executing it in CI with org credentials lets a bad diff exfiltrate secrets, assume the deploy role, or tamper with other repos. The workflow implements all five boundaries:

  1. Split CI — untrusted execution is credential-less. The job that checks out and runs the diff (build-test) runs with permissions: contents: read, no secrets, no OIDC, no write token, and egress blocked (harden-runner). The patch executes only there, where there is nothing to steal and nothing to assume. Every privileged action (the eventual OIDC role, the draft-PR open) runs in a separate gate-and-pr job that never checks out or executes patch-controlled code — it consumes the build/test report as data only. There is no pull_request_target + head-ref checkout (the "pwn request" anti-pattern).
  2. Trust-control-surface denylist (CI-side hard fail). The guard job rejects any diff that touches .github/workflows/**, IAM/policy IaC (CDK/SAM/Terraform), branch-protection / CODEOWNERS / Dependabot config, or files outside the task's declared scope. The match is not naive: it canonicalizes paths, rejects parent-directory traversal, and inspects rename from/to headers, so a rename into a denied path — or path indirection — cannot bypass it. Such a diff is escalated to mandatory human + GPT cross-review, never auto-built.
  3. Diff integrity, box → CI. The builder records the candidate diff's sha256 in the task ledger (foundation agent_team.state_store content-hash idiom). CI re-hashes the diff and verifies it equals the ledger-recorded hash before applying (in both guard and again pre-apply in build-test). A tampered or substituted diff fails the hash check.
  4. Pure-code pass/fail gate over authenticated results. Mirroring secrev's "one pure-code script owns the block decision," the gate-and-pr gate reads only the authenticated needs.*.result job conclusions (GitHub-controlled, patch-independent) keyed to the run id + diff hash. It never trusts a success/failure file or artifact the patch could have written. The verifier agent only reads failures to propose the next fix; it cannot declare success.
  5. Branch protection is the final enforcement. The draft PR targets a protected branch; the locked-down checks are required; merge needs them green plus the security-review, the Claude Code App review, and human approval. The agent never auto-merges (D2).

Threat-model honesty (§3.3.2). The diff hash protects box → CI transit (tamper/substitution), not a box that is itself compromised — the box is in the trusted computing base for what it proposes. The real backstops against a bad box are the credential-less build job, the trust-control-surface denylist, and above all the human review of the draft PR plus required checks (nothing merges without Adam).

Job graph

workflow_dispatch (task_id, diff_artifact_name, expected_diff_hash, declared_scope)
        │
        ▼
   guard            contents:read, no secrets — validates the diff as DATA:
   (boundaries 2,3) re-hash + denylist + scope. Never applies it.
        │ (needs)
        ▼
   build-test       contents:read, no secrets, no OIDC, egress blocked —
   (boundary 1)     the ONLY job that applies + runs the UNTRUSTED patch.
        │ (needs)   Emits a NON-authoritative report artifact.
        ▼
   gate-and-pr      privileged home, but NEVER checks out patch code. Pure-code
   (boundaries 1,4,5) gate over authenticated needs.*.result → DRAFT PR
                    (hard-disabled until the review gates pass).

permissions: {} at the workflow level (least privilege); each job re-declares its own grant explicitly. The trigger is workflow_dispatch only — the patch never runs in a context carrying write or secret scope.

SHA-pinned actions (handbook Pinning Principle, §3.3.2)

Every third-party action is pinned to a full commit SHA with the human-readable tag in a trailing comment:

Action SHA Tag
actions/checkout 11bd71901bbe5b1630ceea73d27597364c9af683 v4.2.2
actions/download-artifact fa0a91b85d4f404e444e00e005971372dc801d16 v4.1.8
actions/upload-artifact b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 v4.4.3
actions/setup-python 0b93645e9fea7318ecaed2b359559ac225c90a2b v5.3.0
step-security/harden-runner 0080882f6c36860b6ba35c610c98ce87d4e2f26f v2.10.2

Relationship to the foundation

This leaf imports the committed Plane-2 foundation contracts verbatim (it does not redefine them):

  • The diff-hash recorded in the ledger and re-checked in CI is the same content-hash idiom as agent_team.state_store.compute_content_hash (§6.7).
  • The task this workflow verifies is an agent_team.task_model.TaskRecord; its candidate_diff + diff_hash fields (§3.3) are exactly the expected_diff_hash this workflow consumes, and ci_results is what the verifier writes back from the authenticated gate (boundary 4).
  • The ledger that records provenance (diff hash, run id, gate decision) is the agent_team.db schema (pending_questions / budget_ledger live there; per-task CI provenance is recorded against the task thread).

Tests

The workflow's embedded gate logic (diff integrity, the trust-control denylist with path-canonicalization + rename/copy/delete detection, the symlink-escape reject, and declared-scope enforcement) is stdlib-only, type-hinted, and ruff-clean, and is covered by a committed, runnable suite: ../tests/test_ci_gate_workflow.py extracts the inline guard script from this YAML and executes it against good and adversarial diffs — clean in-scope, hash mismatch, workflow delete, copy-into-denied, symlink addition, non-UTF-8, out-of-scope, unscoped, and escaping-scope. Run it with the rest of the suite: python3 -m pytest agent-team/tests/ -q from the repo root. (The claim that the gate is "verified" is therefore backed by that test, not by authoring alone.)

Deploy gating (do NOT skip)

Before this ships (§3.3.2, §7.1 P3):

  1. /sh-security-review over this workflow (IaC + untrusted-input handling).
  2. Mandatory GPT-4.1 cross-review of the workflow and the Option-B OIDC role it will assume (IAM change).
  3. A documented, exercised rollback (remove the role, revert the workflow).
  4. Only then: uncomment the id-token / pull-requests: write grants, enable the draft-PR step, and promote to Sea-Haven-Industries/.github. Draft PRs only; never auto-merge.