Cross-family round 1 plus the /sh-security-review verifier confirmed 11
findings on the floor reduction, all documentation defects; no policy
statement changes. The one HIGH: the Terraform migration checklist never
widened the boundary, so a Lambda-bearing Terraform migration would deploy
green and lose every data-plane call at first invoke. Checklist step 2 now
carries the widening requirement, step 3 verifies deployed boundary content,
and the terraform-substrate header no longer reads as 'Terraform path
unaffected'. Also corrected: Description is a REPLACEMENT property (a
Description edit wedges the custom-named policy and CFN's remedy is the
forbidden rename), the sanctioned-source contradiction, the false
AWSLambdaVPCAccessExecutionRole parity claim, the KMS log-group category
error, stale size numbers (691/5,453), the same-PR widening contradiction,
per-workload residue text, a LoggingConfig silent-log-loss note, the
us-east-1 region pin rationale, and ENI DoS deferral now tracked as
INFRA-200.
Security review (6 detectors + proof-or-kill verifier) confirmed 1 critical and
1 high in the first revision, both inherited by mirroring the SAM copy's
Resource "*" role grants:
- C1 (critical): iam:UpdateAssumeRolePolicy on "*" with DenySelfMutation
covering only three name patterns lets the principal repoint the
AdministratorAccess CDK bootstrap role's trust policy to an external account.
- C2 (high): the SAM justification for role/* (SAM auto-roles land at path /
with no settable RolePath) does not transfer -- Terraform's aws_iam_role
supports path.
Fixes, closing the class at the root rather than by denylist:
- All role writes, boundary sets and PassRole confined to role/tf-managed/*;
reads split into a separate statement that keeps Resource "*".
- DenySelfMutation extended to cdk-hnb659fds-*, OrganizationAccountAccessRole
and seahaven-* as defense in depth.
- OIDC provider made conditional (CreateOIDCProvider), mirroring the sibling
substrate, so a first-create rollback is recoverable rather than wedging the
stack in ROLLBACK_COMPLETE against a Retained orphan.
- README corrected: the guardrail policy is NOT Retain (only the provider is),
so the Deny backstops do not survive a stack delete.
checkov CKV_AWS_109 no longer fires on this template, so no suppression is
needed. The template header records every divergence from the SAM copy.
New stack seahaven-terraform-substrate (instances terraform-substrate-prod +
terraform-substrate-dev): app.terraform.io OIDC provider and the shared
boundary-gated guardrail policy seahaven-hcptf-iam-management that
per-workspace Terraform apply roles attach at migration time. No roles are
pre-provisioned (accumulator pattern, parallel to githubdeploy-*).
Guardrail statements mirror seahaven-cfn-exec-iam-management byte-identically
except DenySelfMutation, whose scope extends to hcptf-* alongside the
GitHub-substrate principals. Explicit stack dependency on the same-account
deploy-substrate stack (boundary ARN appears only in Condition strings, so
CFN infers no edge).
