fix(node): owner-gate create_task repo_id against hosted repos

[Gravirei]

Summary

create_task no longer binds a caller-supplied repo_id verbatim. A repo_id naming a hosted, non-quarantined repo is accepted only from that repo's owner; anything else keeps the previous behavior.

Motivation & context

Closes #496

Any signed caller could plant a task — payload and UCAN included — under a repo id it does not own. Once task reads are repo-gated (#464), such an injected task surfaces exactly to that repo's readers and is claimable by the named assignee, so the write side has to verify ownership of the supplied repo_id.

Kind of change

• Security fix

What changed

• gitlawb-node (api/tasks.rs, graphql/mutation.rs): REST POST /api/v1/tasks and GraphQL createTask resolve a supplied repo_id via get_repo_by_id and require require_repo_owner (403 otherwise). Quarantined ids are treated as unknown — 403ing them would confirm a real id — and unknown ids stay oracle-free opaque labels (unscoped under the Unauthenticated task reads expose agent-task UCAN tokens, payloads, and private-repo IDs on both GraphQL and REST #268/fix(node)!: Gate agent-task reads behind visibility rules #464 read contract, which fails closed on ids that resolve to no hosted repo). Repo-less creation is unaffected.
• gitlawb-node (api/mod.rs): pinned the new gate with a require_repo_owner( row for create_task in the authz_guard drift test, alongside the existing signer-binding row.
• Tests: REST deny/allow matrix (non-owner 403 with no repo details in the body, owner 201, repo-less 201, unknown id 201, quarantined id 201) and the GraphQL counterpart.

How a reviewer can verify

cargo test -p gitlawb-node create_task
cargo test -p gitlawb-node authz_guard
cargo test --workspace
cargo fmt --all -- --check
cargo clippy --workspace --all-targets -- -D warnings

All green locally against the compose Postgres.

Before you request review

• Scope is one logical change; no unrelated churn
• cargo test --workspace passes locally
• New behavior is covered by tests (required for fixes)
• cargo fmt --all and cargo clippy --workspace --all-targets -- -D warnings are clean
• Commit titles use Conventional Commits (feat(...), fix(...), docs(...))
• Docs / .env.example updated if behavior or config changed (or N/A — no config change)
• Checked existing PRs so this isn't a duplicate (fix(node)!: Gate agent-task reads behind visibility rules #464 gates reads; this gates the write side)

Notes for reviewers

assignee_did is intentionally still taken verbatim — it is the delegation target and is bound to the signer at claim time on both surfaces. The gate choice is owner-only rather than read-gated (unlike create_bounty): tasks are executable work orders carrying payload+UCAN, and a read gate would leave injection into public repos wide open.

Summary by CodeRabbit

• Bug Fixes
  • Task creation linked to an existing, non-quarantined hosted repository is now limited to that repository’s owner in the API and GraphQL.
  • Requests from non-owners receive a forbidden response without disclosing repository or owner details, and no task is created.
  • Tasks without a repository ID, or with an unknown or quarantined repository ID, remain accepted. Database or quarantine-check failures return an error.

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📒 Files selected for processing (3)

• crates/gitlawb-node/src/api/tasks.rs
• crates/gitlawb-node/src/graphql/mutation.rs
• crates/gitlawb-node/src/test_support.rs

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📝 Walkthrough

Walkthrough

REST and GraphQL create_task now check ownership when a supplied repo ID resolves to a non-quarantined repo. Unknown and quarantined IDs bypass the ownership check. Tests cover authorization outcomes and error privacy.

Changes

Task repo authorization

Layer / File(s)	Summary
Ownership checks and validation crates/gitlawb-node/src/api/mod.rs, crates/gitlawb-node/src/api/tasks.rs, crates/gitlawb-node/src/graphql/mutation.rs, crates/gitlawb-node/src/test_support.rs	REST and GraphQL create_task check whether the caller owns a resolved, non-quarantined repo. Database lookup and quarantine-check failures use database-error responses. Tests cover owner and non-owner requests, repo-less tasks, unknown and quarantined IDs, and verify that forbidden responses omit repo and owner details.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: beardthelion

Merge Risk: ⚪ Minimal · up to abc03

The change rejects foreign-owner task creation for hosted, non-quarantined repositories while preserving the intended exceptions. No actionable merge-blocking issue remains; merge after normal checks pass.

Security Architecture Review

Security architecture risk: 🔵 Low · up to abc03

The ownership check blocks ordinary unauthorized task creation against hosted repositories. However, different success and denial responses let a signed non-owner confirm that a known private repository ID is hosted. The disclosure is limited to repository presence, and existing lifecycle limitations are not introduced by this change.

Retained concerns

• Low · security · observed: A signed non-owner supplying a private repository ID receives a denial when that ID names an active hosted repository, but success when it is unknown or quarantined. Before this PR, both cases were accepted. This confirms hosting presence even for repositories without existing task rows. It requires a candidate ID and discloses neither repository contents nor owner details; existing task-ID exposure and UUID-based repository creation limit, but do not eliminate, the incremental disclosure.

Security review details

Security Blast Radius

• inferred — The introduced disclosure is independently probeable for candidate IDs across the node's active hosted repositories by a signed non-owner. Its demonstrated outcome is hosting-presence confirmation, not access to repository contents or additional execution authority.

Trust Boundaries and Controls

• observed — GraphQL HTTP requests receive identity through optional signature verification and server-side context injection; createTask requires that identity and rejects a mismatched delegator. REST writes use signature and UCAN middleware. Both paths compare the authenticated caller with repository ownership before insertion.

Resilience and Maintainability Implications

• observed — Validation and insertion are separate operations, and task rows retain no authorization provenance. Previously accepted opaque labels can later match hosted mirror IDs. A quarantine-update helper exists, but its production release endpoint is deferred. These lifecycle limitations predate the gate and are not demonstrated PR regressions.

Hardening Proposals

• proposed — Define the hosting-presence confidentiality contract explicitly. If presence must remain private, design indistinguishable externally visible outcomes for hidden hosted IDs and unknown labels while preserving unauthorized-write rejection.
• proposed — For future lifecycle hardening, distinguish opaque task labels from authorized repository associations and define authorization at repository admission or quarantine release, rather than allowing a label's meaning to change implicitly.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main security fix: enforcing repository ownership for caller-supplied task repo IDs.
Description check	✅ Passed	The description is complete and follows the repository template. It explains the security issue, affected REST and GraphQL paths, behavior for owned, foreign, quarantined, unknown, and repo-less IDs, …
Linked Issues check	✅ Passed	Issue #496 requests authorization before accepting a caller-supplied repo_id. REST POST /api/v1/tasks and GraphQL createTask now require the authenticated owner for hosted, non-quarantined repos…
Out of Scope Changes check	✅ Passed	The authorization guards, REST and GraphQL handling, integration tests, and authz_guard drift-test entry directly implement issue #496. The supplied whole-PR summary identifies no unrelated changes.
Docstring Coverage	✅ Passed	Docstring coverage is 85.71% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files. (1 skipped: 1 t…

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @crates/gitlawb-node/src/api/tasks.rs:
- Around line 116-132: Update the error mappings for get_repo_by_id and
is_repo_quarantined to log database errors server-side and return a generic
“internal error” response instead of exposing raw error details.

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📒 Files selected for processing (4)

• crates/gitlawb-node/src/api/mod.rs
• crates/gitlawb-node/src/api/tasks.rs
• crates/gitlawb-node/src/graphql/mutation.rs
• crates/gitlawb-node/src/test_support.rs

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[beardthelion]

Verified the gate end to end on this head. Built the tree, ran the create_task suite green, then removed the new check in a scratch tree and watched the stranger case go red (201 instead of 403); did the same for the quarantine arm and for the GraphQL copy. Both surfaces deny a non-owner naming a hosted repo and keep unknown, quarantined, and absent ids accepted, matching the contract in the comments.

One scope note, not an ask: the read side that gives this teeth (task_visible and friends) lives in #464, still open. I checked that diff: it resolves task.repo_id against repos.id, the same keyspace get_repo_by_id matches, and it dead-ends slash-form mirror ids, so this gate lands cleanly when that ships. On today's main a planted task's repo_id is still just a label.

Findings

• [P2] Return an opaque body from the new repo-lookup failure arms
  crates/gitlawb-node/src/api/tasks.rs:119
  Both new map_err arms serialize e.to_string() into the 500 JSON body. The GraphQL half of this same PR opaques the identical failures through graphql_db_err, and the repo already has the fixed envelope for this: {"error":"db_error","message":DB_ERROR_MESSAGE} (error.rs, used by api/events.rs). The file's older arms do the same thing, so this ask covers only the two lines this PR adds: log the real error with tracing and return the fixed shape.

• [P3] Assert the denied write did not persist
  crates/gitlawb-node/src/test_support.rs:633
  I moved the gate below db.create_task and every test stayed green while the stranger's task landed in the table under the victim's repo id. A denial that still writes is exactly what this change exists to prevent. After the 403 arm, read the task store back and assert no row carries that repo_id; same for the GraphQL test.

• [P3] Pin the quarantined and unknown-id arms on the GraphQL copy too
  crates/gitlawb-node/src/graphql/mutation.rs:54
  The gate is a second copy, not a shared helper. I dropped !quarantined on the GraphQL side and all four tests stayed green, so that copy can regress silently. Either cover the quarantined/unknown arms in the GraphQL test or factor the check into one helper both surfaces call.

• [P3] Correct the no-existence-oracle comment
  crates/gitlawb-node/src/api/tasks.rs:109
  The comment claims "no existence oracle either way", but the 403-vs-201 split between a hosted non-quarantined repo id and an unknown id is itself an oracle: a stranger holding a private repo's id learns it is hosted here. The behavior is defensible (denying foreign repos requires distinguishing them, and repo ids already leak via the open task list on this base); the comment should describe the split honestly rather than claim it away.

Not an ask, recorded only: a task filed under a quarantined repo id still stores that id verbatim, so if a quarantined row is ever released the label binds to a live repo without ever passing the owner check. No release path ships today (set_repo_quarantine has only test callers), so this is forward-looking rather than a defect.

One process note, not a finding: the cargo audit failure is advisories against lru, core2, and spin in the shared lockfile, unrelated to this diff, which touches no Cargo files. Nothing for you to do there.