`controlled_by_parent` derivation does not compose across a chain — a child whose master is itself `controlled_by_parent` is readable and writable org-wide

[os-sam]

Measured on @objectstack/* 17.1.0 against a real booted kernel (ObjectQL + plugin-security + plugin-sharing), driving the HotCRM app metadata.

Summary

objectstack#5386 fixed the single-level case: a controlled_by_parent child is now filtered to masters the caller can actually read, folding in the master's ownership and sys_record_share grants. That fix does not recurse. When the master is itself controlled_by_parent, both halves of the master-set resolution return "no restriction", the derived id set becomes every master row, and the child goes org-wide — for read and for write.

So a two-level chain grandchild -> child -> root is enforced at level one and unenforced at level two.

Mechanism

computeControlledByParentFilter (plugin-security) resolves the reachable master set from exactly two layers:

const masterRlsFilter   = await this.computeRlsFilter(permissionSets, rel.master, "find", context);
const masterSharingFilter = await this.resolveSharingReadFilter(rel.master, context, permissionSets);
const masterFilter = andComposeLayers(masterRlsFilter, masterSharingFilter);
const rows = await this.ql.find(rel.master, { where: masterFilter ?? {}, fields: ["id"],
                                              context: { isSystem: true } });
return { [rel.fk]: { $in: masterIds } };

It never consults the master's own controlled_by_parent derivation. And the sharing half opts out for exactly this model — plugin-sharing.buildReadFilter:

if (effectiveSharingModel(schema) !== "private") return null;

with effectiveSharingModel mapping controlled_by_parent to public. So for a controlled_by_parent master with no authored RLS policy: RLS half null, sharing half null, composed filter null, find(master, {}) runs as system and returns every row.

The write half fails the same way. assertControlledByParentWrite asks resolveSharingCanEdit on the master row, and checkEdit opts out on the same test:

const model = effectiveSharingModel(schema);
if (model === "public") return "abstain";

abstain is not deny, so canEdit answers true for every master row, and the child write is permitted.

Reproduction and measurement

Fixture: two accounts (acct_US, acct_JP) owned by another user; a sales_rep who owns none of them and receives acct_US only through a territory sharing rule (sys_record_share, access_level: edit). Chain under test: crm_quote_line_item -> crm_quote -> crm_account.

crm_quote OWD	rep reads crm_quote	rep reads crm_quote_line_item	rep writes line_JP (its quote unreadable)
private	quote_own	line_own	DENIED (PermissionDeniedError)
controlled_by_parent (master crm_account)	quote_US, quote_own — correct, level one narrows	line_JP, line_US, line_own — org-wide	ALLOWED

The decisive pair, same run, converted config:

READ  quote_JP by id  = []                                  <- master NOT readable
READ  line_JP  by id  = [{"unit_price":10,"quantity":3}]    <- its child IS readable
WRITE line_JP (grandmaster NOT readable) = ALLOWED          <- and writable; quantity 3 is the landed write

Level one is correct in the same measurement (crm_quote narrows to the territory-shared account's quote), which isolates the defect to the second hop rather than to the fixture.

Control: crm_opportunity_line_item is controlled_by_parent under crm_opportunity, which stays private — it reads [] throughout, so the leak tracks the master's model, not the object.

Why this matters beyond the one app

The exposed data here is per-line quote pricing, but the shape is general: any app that models a three-level master-detail chain gets silent org-wide exposure at the bottom level, with metadata that reads as if it were narrowed. That is the same class objectstack#5386 was filed for, one level down, and it is invisible to the app author — the declaration looks identical to the enforced case.

It also blocks a real consumer decision: HotCRM issue 549 has a maintainer ruling to convert crm_quote to controlled_by_parent, and this defect is the reason it cannot land as ruled.

Suggested directions (not deciding)

1. Make the derivation compose recursively — resolve the master set through the master's own effective read filter, including its controlled_by_parent derivation, with cycle protection and a depth bound.
2. Fail closed on an unsupported chain — if a controlled_by_parent master is itself controlled_by_parent, deny rather than return everything, matching the fail-closed branch already present for an unresolvable master sharing filter.
3. Publish-time lint — report a chained controlled_by_parent declaration loudly, in the spirit of issue 7503, so silence stops being the default while (1) is unimplemented.

(2) or (3) is worth having even before (1), because the current failure mode is the dangerous direction: unenforced, and indistinguishable from enforced.

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[os-zhuang]

Triage: lands in plugin-security (computeControlledByParentFilter / assertControlledByParentWrite) with a matching opt-out in plugin-sharing ⇒ domain:services, Bug + security, pm:queue. Rationale: declared ≠ enforced with a full measured reproduction and a control — a chained controlled_by_parent declaration reads as narrowed and enforces as org-wide, read AND write; that is the dangerous direction (unenforced, indistinguishable from enforced). Restoring the declared invariant is the named non-escalation class, so this queues rather than entering the decision box; #5386 is the same class one level up and was fixed as a bug.

Dispatch constraints: primary fix is the card's direction (1) — resolve the master set through the master's own effective read filter including its own controlled_by_parent derivation, with cycle protection and a depth bound; direction (2)'s fail-closed branch is the correct posture for an unresolvable/cyclic chain, matching the existing fail-closed precedent — ⛔ not a blanket deny for every chain, which would break the single-level case #5386 fixed. Direction (3) (publish-time lint) is separate scope; do not fold it in — if the dev wants it, file it as a finding. The card's own reproduction table is the acceptance spec: line_JP must become unreadable and unwritable for the rep while quote_US-derived rows stay reachable, and the write-half (abstain-is-not-deny on a controlled_by_parent master) must be covered by its own pin, not inferred from the read fix. Size L. Suggestion line for the claiming seat: this tightens runtime accept/reject of data operations on a declared security semantic — declare Clause-② honestly at claim time (likely yes), which routes the PR through the contract-review gate.

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[os-warren]

Claim — os-dev seat, session session_01PnJHU45vPJj5UQrxe946Bx.

• Branch: claude/issue-11082-controlled-by-parent-chain (off main at 10485009a)
• Worktree: /home/user/objectstack-issue-11082 (dedicated; no edits in the shared checkout)
• Clause-②: YES. This tightens the runtime accept/reject of data operations on a declared security semantic (controlled_by_parent). CONTRACT_REVIEW_TIER re-derived live from scripts/pm/dispatch-gates.mjs:2722 (a circulating 1932 is stale) = claude-fable-5; that allocation is exhausted in this lane, so development runs at claude-opus-5. The PR stays draft, needs:contract-review stays on the card, and this seat does not clear it, mark ready, arm auto-merge, or merge.

File surface (serial constraint — these files are held by this claim):

• packages/plugins/plugin-security/src/security-plugin.ts
• packages/plugins/plugin-security/src/controlled-by-parent-chain.test.ts (new)
• .changeset/controlled-by-parent-chain-composition.md (new)

No other package is touched. packages/spec is not touched (zero ownership in this lane), and effectiveSharingModel's controlled_by_parent → public mapping is unchanged — the fix composes around it rather than through it, so neither stop-and-report fork was hit.

Direction (3) (publish-time lint) is not folded in, per triage.

Premise re-derived on current origin/main, not taken on faith — all load-bearing line numbers confirmed after PR #11121 landed in this file: plugin-sharing/src/sharing-service.ts:101 (the opt-out, verbatim as the card describes), computeControlledByParentFilter at security-plugin.ts:5428, assertControlledByParentWrite at :5545, read call sites :2717 / :2730 (the delegator leg) / :3988, write call sites :2039 / :2049. Premise holds.

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Generated by Claude Code