[cristim]

Summary

Derive the boundary guard's module walk from what the environment root instantiates, and scope lambda:InvokeFunction in the boundary to cudly-* functions. Re-files the lost #1827 (see #511).

Why

• findAwsModuleFiles kept only .tf files under an aws path segment, so modules/build, modules/deployment-checks and environments/aws/*.tf were invisible to the action-coverage, role-boundary and managed-policy guards. Mutation proof is in test(iac/aws): boundary guard walk misses deploy-path modules; scope lambda:InvokeFunction in the boundary #511: an out-of-boundary ecs:DeleteCluster in modules/build passed the guard.
• WorkloadServiceCeiling allowed lambda:InvokeFunction on Resource = "*"; the only workload use is the API Lambda's self-invoke.

Change

• deployPathFiles (policy_guard_test.go): aws-segment walk unioned with the root's *.tf and every module reached through local module blocks, transitively. Non-local or missing sources abort the test (fail closed).
• policy_boundary.tf: lambda:InvokeFunction moved to a new LambdaInvokeCeiling statement on arn:aws:lambda:*:*:function:cudly-*. Safe because the deploy role can only create cudly-* functions (policy_compute.tf), the function is ${stack_name}-api with project_name defaulting to cudly, and no other role grants the action (the other InvokeFunction hits are resource policies, which the boundary does not gate).

NEEDS A HUMAN APPLY of terraform/environments/aws/ci-cd-permissions AFTER MERGE (policy_boundary.tf changed). No plan/apply was run here.

Tests

New: TestDeployPathWalkReachesModulesWithoutAwsSegment (fixture module with no aws segment granting ecs:DeleteCluster, lambda:DeleteFunction; asserts the walk reaches it and the coverage comparison reports both) and TestBoundaryInvokeFunctionIsScopedToCudlyFunctions.

Pre-fix failure (walk reverted):

[FAIL] TestDeployPathWalkReachesModulesWithoutAwsSegment
  policy_guard_test.go:1876: deployPathFiles = [], missing .../modules/build/main.tf, which env/main.tf instantiates

Boundary unscoped:

[FAIL] TestBoundaryInvokeFunctionIsScopedToCudlyFunctions
  policy_boundary.tf: statement "WorkloadServiceCeiling" allows lambda:InvokeFunction on Resource ["*"], want exactly ["arn:aws:lambda:*:*:function:cudly-*"]

Verification

go test -count=1 ./terraform/environments/aws/ci-cd-permissions/: 18 top-level tests pass, 0 fail (main: 16, same suite). Pre-commit hooks (terraform fmt/validate/lint, gosec, trivy) pass.

Closes #511

Summary by CodeRabbit

• Security

  • Restricted deployment permissions so Lambda invocation is allowed only for functions named cudly-*, limiting which functions deployment credentials can invoke.

• Validation

  • Expanded policy checks to include Terraform modules referenced by an environment, including nested local modules, while excluding unreferenced modules.
  • Added checks for uncovered permissions, Lambda invocation scope, and unresolved or unsupported module sources.

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📝 Walkthrough

Walkthrough

The permissions boundary limits lambda:InvokeFunction to cudly-* functions. The policy guard scans environment-root Terraform files and their instantiated local modules. Tests cover module discovery, boundary coverage, and invalid module sources.

Changes

Lambda invocation boundary

Layer / File(s)	Summary
Restrict Lambda invocation scope terraform/environments/aws/ci-cd-permissions/policy_boundary.tf, terraform/environments/aws/ci-cd-permissions/policy_guard_test.go	The boundary removes lambda:InvokeFunction from the wildcard-resource statement and allows it only on arn:aws:lambda:*:*:function:cudly-*. A test checks that each non-Deny statement allowing the action uses that resource.

Deploy-path policy guard

Layer / File(s)	Summary
Discover and validate deploy-path modules terraform/environments/aws/ci-cd-permissions/policy_guard_test.go	The guard scans Terraform files at the environment root and follows local module sources. Tests verify that instantiated modules outside AWS-named paths are included, unreferenced modules are excluded, uncovered actions are detected, and invalid or non-local sources return errors.

Priority: ⬆️ High

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix · Severity of issue fixed: High

Merge Risk: 🔵 Low · up to 9863a

The new guard and the scoped Lambda permission look sound. One test assertion is slightly weaker than it could be, but another test already covers the gap. A human apply is still required after merge.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	#511 requires coverage of the environment root and all transitively instantiated local modules, including modules without an aws path segment. walkDeployPath unions the AWS-path scan with root `.t…
Out of Scope Changes check	✅ Passed	The changes are limited to the CI/CD permissions boundary, the deploy-path guard, and tests for these changes. The boundary update and guard update directly implement #511. No unrelated change is demo…
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 1 files.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely identifies both primary changes: deriving the boundary guard walk from the module tree and scoping lambda:InvokeFunction.

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at
@terraform/environments/aws/ci-cd-permissions/policy_guard_test.go:
- Line 380: Separate the files already discovered from those already queued for
reading in the module traversal around addDir: use a queued set to prevent
duplicate reads, while keeping seen for collected files, so an aws-path file is
still queued when encountered again. Add a fixture where the root reaches
modules/x/aws/m, which imports modules/build, and assert that
modules/build/main.tf is included.

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• terraform/environments/aws/ci-cd-permissions/policy_boundary.tf
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🔇 Additional comments (1)

terraform/environments/aws/ci-cd-permissions/policy_guard_test.go-1937-1937 (1)

1937-1937: 🔒 Security & Privacy | 🟠 Major | ⚡ Quick win

⚠️ Unverified finding
Verification ran but could not confirm this finding. It is shown for review, not as a verified issue.

Reject unparsed Resource entries before accepting the boundary scope.

If Resource = ["arn:aws:lambda:*:*:function:cudly-*", local.extra_resource] and local.extra_resource is "*", statementResources returns only the quoted ARN. The test passes even though the resulting policy also covers all functions. Reject nonliteral entries before comparing resources; the existing unreadListElements helper can identify them. Terraform permits expressions in list elements and encodes the resulting list into JSON. (developer.hashicorp.com)

Proposed check

 for _, stmt := range stmts {
+    if refs := unreadListElements(stmt, resourceAssignmentPattern); refs != "" {
+        t.Errorf("%s: statement %q has nonliteral Resource entries: %s", boundaryFile, statementSid(stmt), refs)
+        continue
+    }
     if got := statementResources(stmt); !equalStringSets(got, []string{wantResource}) {

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[cristim]

Targeted independent triage of CR review5452243600 Resource-expression suggestion: no source change, because the existing package-wide literal-list invariant already guards this case. guardedPolicyFiles464 globs policy_*.tf and excludes only policy_iam.tf at471-472, so policy_boundary.tf is included. TestPolicyDocumentsUseLiteralActionAndResourceLists1685-1714 passes every Resource assignment to unreadListElements at1702-1704 and rejects local.extra_resource at1705. statementResources588-598 is intentionally literal-only under that invariant. Adding the same check inside the Lambda assertion would duplicate the existing guard. This is source-based counter-evidence, not a claim of executed mutation proof; a valid mixed-literal/local Resource mutation will be checked with the next coordinated local verification slot. Exact9863 source remains unchanged; fresh CI all25 checks SUCCESS. Existing full-suite reservation executed zero tests and remains deferred behind P0 reservations. Latest owner policy makes CR optional but preserves resolution of known actual findings.

[cristim]

The nested-module fix is published at 9863a2441c865f99f43d647b3b38348d66b3d331. The worktree is clean. The full PR changes only terraform/environments/aws/ci-cd-permissions/policy_boundary.tf and policy_guard_test.go.

An independent reviewer examined the full PR diff at this exact SHA against the AWS IAM boundary and Lambda invocation contracts. Verdict: no actionable findings. The existing seeded-module traversal finding is fixed by separate queue membership. Nested local-child and remote-source fixtures cover the failure.

Independent controls used Go 1.26.6, GOWORK=off, -mod=readonly, -race, -count=1, and the canonical persistent test lock. Go overlays preserved the committed source while substituting the relevant historical implementation:

Control	Observed result
Final tests with parent discovery	Intended missing non-AWS child failure, exit 1, 0.545s
Final test with parent boundary	Intended Resource [*] scope failure, exit 1, 0.329s
Final tests with original b23a65e9 traversal	Intended missing nested child and unchecked remote-source failures, exit 1, 0.344s
Exact fixed head, three top-level controls and five fail-closed cases	Pass, exit 0, 1.549s

The fixed selection was:

GOTOOLCHAIN=go1.26.6 GOWORK=off lockf -k -t 600 /tmp/agent-locks/cloud-commitments-platform-test-suite.lock go test -mod=readonly -race -count=1 -v -overlay=/private/tmp/pr512-review-controls/final-9863a244-20261008/head-controls-overlay.json -run '^Test(DeployPathWalkReachesModulesWithoutAwsSegment|DeployPathWalkFailsClosed|BoundaryInvokeFunctionIsScopedToCudlyFunctions)$' ./terraform/environments/aws/ci-cd-permissions

The historical controls used the same flags with explicit Go overlays and selected tests. No setup failure, race, panic, timeout, or skip was accepted as regression proof. Raw commands, overlays, output, and hashes are preserved in /private/tmp/pr512-review-controls/final-9863a244-20261008/.

Fresh go build ./... and make build passed at 9863a244; the latter embedded that Git SHA. Normal commit hooks passed before publication. Publication used the existing branch lock and an exact b23a65e9 remote-head lease. All 25 returned GitHub checks are SUCCESS on the published fixed head, verified again this turn.

Current main is f2d60df86209eea85d81e9091c20832bd670a65f. Its changes since the reviewed base do not touch Terraform or the Lambda invocation path. Module and store changes still require final combined-tree verification.

The additional Resource-expression suggestion is covered by the existing global literal-list invariant at policy_guard_test.go:1685-1714. It scans the boundary and rejects unread Resource references at lines 1702-1705. Independent targeted triage found no source fix needed. A scratch mutation probe has passed two script reviews; it has not executed.

Remaining local gate: the coordinated full relevant suite and Resource mutation proof after the P0 #646 owner releases its existing heavy-test reservation. The earlier full-suite lock wait expired before executing any tests; it is neither a pass nor a test failure. No additional test queue or watcher was created.

Evidence covers realistic synthetic module fixtures and actual-tree IAM policy text. No AWS account call, Terraform plan, or Terraform apply occurred. Updating the deployed boundary still requires the PR's documented privileged human bootstrap apply after merge. That activation gap is recorded honestly and is not a live-account merge gate. CodeRabbit is optional under the latest owner policy; known actual findings remain subject to resolution.

[cristim]

The granted verification window is complete and released. Source remained clean at exact independently reviewed head 9863a2441c865f99f43d647b3b38348d66b3d331 before and after execution.

The repository race suite ran under the canonical persistent lock:

lockf -k -t 1 /private/tmp/agent-locks/cloud-commitments-platform-test-suite.lock env GOTOOLCHAIN=go1.26.6 GOWORK=off GOMAXPROCS=2 go test -mod=readonly -race -short -json -count=1 -p=1 -timeout=15m ./...

Actual process exit: 0. Recorded results: 31 packages passed, 7,144 test pass actions, and zero fail actions. Five packages had no tests. The four skipped tests were TestDiscoverOrgAccounts_CancelledContext, TestGetFederationIaC_TfvarsAutoLoadedByTerraform/aws-cross-account, TestRevokePurchase_FourEyesApproval, and TestRevoke_4EyesMode_TODO. This is the repository suite in short mode, not a claim of native integration or live-cloud acceptance.

The two-pass-reviewed Resource mutation runner also exited 0. Its positive case passed both selected guards. Its synthetic valid HCL case added local.extra_resource = "*" alongside the allowed literal Lambda ARN. TestPolicyDocumentsUseLiteralActionAndResourceLists failed with the expected nonliteral Resource diagnostic, while the isolated Lambda assertion passed. The runner rejected unrelated runtime/setup/race failures, required exact test and package results, and verified scratch artifact hashes while holding the lock. No selected test was skipped.

This executed mutation confirms the independent triage of CR review 5452243600: the existing global guard already rejects the suggested widening. No duplicate source check is needed. The earlier seeded-module finding remains fixed and independently reproduced as documented above.

Raw suite output and summary are preserved at /private/tmp/herdr-codex-takeover-20261007/pr512-granted-suite-9863-20261008.jsonl and pr512-granted-suite-9863-summary.json. Mutation commands, output, overlays, hashes, and verdict are in /private/tmp/herdr-codex-takeover-20261007/pr512-resource-reference-9863a244-rdqzxbed/.

Fresh GitHub queries after these controls report the same head, all 25 returned checks SUCCESS, and CLEAN/MERGEABLE. Current main is f2d60df86209eea85d81e9091c20832bd670a65f; its changes since the reviewed base leave the Terraform and Lambda invocation paths unchanged. The local suite ran on the committed PR tree, not an uncommitted merge with main.

Local builds, normal hooks, full-PR independent review, and historical fail-before/pass-after controls at this SHA are recorded above. No AWS account calls or Terraform plan/apply occurred. The documented privileged bootstrap apply remains an activation coverage gap after merge. CodeRabbit is optional under the latest owner policy; no throttle or absent-review waiver is claimed.

The terminal reservation release has been sent to the coordinator and #646 owner. Normal merge awaits coordinator main sequencing and the immediate unchanged-head, green-CI, mergeability, and protection checks under the canonical merge lock.

[cristim]

Independent full-PR review (cc-cli-w2, Claude Opus 5.5; did not write this PR) at exact head ab6dd6fc8281d3f5ea69a10e124e73b8a88c3241

Verdict: CLEAN, no actionable findings. Two non-blocking PR-body nits below.

Rebase. git range-diff of 76a30647/9fe23dd9/9863a244 vs ad8f406a/4b360a0b/ab6dd6fc is = for all three commits; head sits on current origin/main.

Boundary change (policy_boundary.tf). Checked the scoping argument against the source:

• The only workload identity grant of lambda:InvokeFunction is async_self_invoke on aws_lambda_function.main.arn (modules/compute/aws/lambda/main.tf:485-497). Every other hit (secrets/aws/main.tf:401, cleanup-lambda/main.tf:121, lambda/main.tf:583..799) is an aws_lambda_permission resource policy, which the boundary does not gate.
• The function name is ${var.stack_name}-api (lambda/main.tf:29), and the env passes local.stack_name = "${var.project_name}-${var.environment}-${random_id.suffix.hex}" (environments/aws/main.tf:55). var.stack_name is only a tag. Every tfvars sets project_name = "cudly", and the deploy role can only create function:cudly-* (ci-cd-permissions/policy_compute.tf:30), so cudly-* covers every function a boundaried role can legitimately invoke.

Guard walk (policy_guard_test.go). Read walkDeployPath in full. It is the aws-segment seed unioned with env-root *.tf plus transitive local module sources, and it fails closed on non-literal, remote and missing sources. Commit 3's split of seen/queued fixes a real hole: seeded aws-segment files were marked seen before being queued, so their module blocks were never followed.

Evidence I reproduced (no writes to the writer's worktree; mutations ran in a scratch git archive copy of terraform/ or via go test -overlay; no -race):

• go test -count=1 -v ./terraform/environments/aws/ci-cd-permissions/ at the head: 19/19 top-level tests PASS.
• Probe A, the test(iac/aws): boundary guard walk misses deploy-path modules; scope lambda:InvokeFunction in the boundary #511 scenario: an aws_iam_role_policy granting ecs:DeleteCluster appended to the real modules/build/main.tf.
  • Main's guard: PASS (the gap).
  • This head: TestBoundaryCoversWorkloadServices FAILS with "does not cover [ecs:DeleteCluster] (granted to a workload role by terraform/modules)".
• Probe B: lambda:InvokeFunction restored to WorkloadServiceCeiling (Resource = "*"). TestBoundaryInvokeFunctionIsScopedToCudlyFunctions FAILS ("allows lambda:InvokeFunction on Resource [*]").
• Probe C: commit 3 reverted via overlay (if seen[e] { continue }). TestDeployPathWalkReachesModulesWithoutAwsSegment and TestDeployPathWalkFailsClosed/remote_source_in_AWS_parent both FAIL. Both new tests are non-vacuous.

Nits (PR body only, non-blocking):

1. "Verification: 18 top-level tests pass (main: 16)" is stale. The head has 19, since TestDeployPathWalkFailsClosed was added in commit 2.
2. The body doesn't mention commit 3 (the seeded-module traversal fix).

CI at this head: when I checked, Unit/Integration/E2E/Lint/Security/Docker were still pending; everything else, including pre-commit and CodeRabbit, had passed. Merge still needs green CI at this SHA, plus the human apply of ci-cd-permissions after merge, as the body says.