fix(node)!: Gate agent-task reads behind visibility rules

.env.example

@@ -272,6 +272,19 @@ GITLAWB_IPFS_RESOLVE_BUDGET_SECS=10
 # from the concurrency caps above). 0 disables. Default 600.
 GITLAWB_IPFS_RATE_LIMIT=600
 
+# Per-client-IP rate limit for the anonymous task read routes
+# (GET /api/v1/tasks, GET /api/v1/tasks/{id}), in requests per hour.
+# Both are publicly reachable (optional_signature). GET /api/v1/tasks runs
+# collect_visible_tasks and returns a visibility-filtered page;
+# GET /api/v1/tasks/{id} runs get_visible_task and returns an opaque 404 when
+# the task is hidden or missing. These reads can require task, repository,
+# and visibility-rule queries even when no task is returned, so the brake
+# bounds the cost of anonymous probes. Keyed on the resolved client IP via
+# GITLAWB_TRUSTED_PROXY. 0 disables. Default: 1200 (a list page
+# followed by per-task reads is a normal client pattern, so this sits above
+# the /ipfs budget). The GraphQL/WS task-read brake shares this budget.
+GITLAWB_TASK_READ_RATE_LIMIT=1200
+
 # ── Creation rate limiting (repo/agent/issue/PR flood brake) ──────────────
 # Max creation requests (POST /api/v1/repos, /api/register, fork, issues,
 # pulls) per client IP per hour, in addition to the per-DID limit. The per-DID

README.md

@@ -69,7 +69,7 @@ Known limitations:
 - Repository write authorization is not secure by default: `GITLAWB_ENFORCE_OWNER_PUSH` defaults to `false` for compatibility, so a valid HTTP Signature identifies a pusher but does not enforce owner-only pushes.
 - UCAN proof chains are validated when supplied, but UCAN capabilities are not consulted by write authorization and the root issuer is not independently trust-anchored. UCANs therefore do not yet grant scoped collaborator access.
 - Agent lifecycle revocation is not enforced by HTTP Signature authorization; do not rely on removing or revoking an agent record to block a compromised signer.
-- Read visibility is not a blanket data-classification boundary: task, IPFS-pin, and Arweave-anchor listings are not repository-gated; withheld path names can be visible to a root reader; and later visibility changes cannot retract content already announced or externally anchored.
+- Task list/get reads (REST and GraphQL) are repository/task-gated and omit `ucan_token`. Read visibility is not a blanket data-classification boundary: IPFS-pin and Arweave-anchor listings are not repository-gated; withheld path names can be visible to a root reader; and later visibility changes cannot retract content already announced or externally anchored.
 - Peer writes are signed by upgraded nodes, but strict signed-peer enforcement is opt-in during rolling upgrades.
 - Current GraphQL mutations require an authenticated signer, but there is no mutation-specific guardrail that prevents a future mutation from omitting that check.
 - Pull-request review comments do not yet have threaded line-level anchors, and merges do not enforce approval requirements.
@@ -412,6 +412,7 @@ Important node settings:
 | `GITLAWB_IPFS_REQUEST_BUDGET_SECS` | Absolute wall-clock budget for one admitted `/ipfs/{cid}` request's acquire+walk lifetime. Per-stage clamps bound the acquire and walk stages to the remaining budget, and no stage starts once it is exhausted; the scan then stops with a retryable 503. The object-type probe and content-read `cat-file` subprocesses are budget-checked before starting and each also run under their own deadline (the lesser of `GITLAWB_GIT_SERVICE_TIMEOUT_SECS` and the remaining budget), reaped via process-group teardown, so a hung `cat-file` cannot hold the request's walk slot past it. One hang path is still unbounded: the probe's object-store readability check is a plain filesystem sweep with nothing to reap, so a wedged filesystem can hold the slot past the deadline. Default 600. Accepted range is 1 to 3153600000 (100 years), since the node derives a deadline from this value and a larger one cannot be represented. |
 | `GITLAWB_IPFS_RESOLVE_BUDGET_SECS` | Shorter budget for the pre-walk CID resolve inside an admitted `/ipfs/{cid}` request: the lookup that maps the requested CID to its git oid(s), which runs while the scarce walk admission is already held. A well-formed CID with no pin row does no probe and no walk work, so without this it could hold a walk slot for the whole request budget while nothing walked, and enough such requests shed every real retrieval at admission. The effective deadline is the lesser of this and the remaining request budget, so a value above `GITLAWB_IPFS_REQUEST_BUDGET_SECS` degrades to the request budget. Only the resolve is on this clock; walk and probe work stay on the request budget, so a slow but progressing scan is never shed by it. Default 10. Accepted range is 1 to 3153600000 (100 years). |
 | `GITLAWB_IPFS_RATE_LIMIT` | Max `/ipfs/{cid}` requests per client IP per hour (route flood brake). 0 disables. Default 600. |
+| `GITLAWB_TASK_READ_RATE_LIMIT` | Max anonymous task-read requests (`GET /api/v1/tasks`, `GET /api/v1/tasks/{id}`) per client IP per hour, sharing the budget with the GraphQL/WS task-read brake. Uses `GITLAWB_TRUSTED_PROXY` to resolve the client IP. 0 disables. Default 1200 (above the `/ipfs` budget to allow list pages followed by per-task reads). |
 | `GITLAWB_TIGRIS_BUCKET` | Optional S3/Tigris shared repo storage bucket. |
 | `GITLAWB_PINATA_JWT` | Optional Pinata/IPFS warm-storage pinning. |
 | `GITLAWB_IRYS_URL` | Optional Irys/Arweave permanent anchoring. |

SECURITY.md

@@ -73,7 +73,7 @@ These are documented limitations of the current live release. They should be pri
 ### Private repository reads
 - Repository and path-scoped visibility checks are enforced for repository API and Git content reads. A denied whole-repository or root read returns the same 404 shape as a missing repository, so the denial does not reveal private-repository existence.
 - Sparse-clone support exposes withheld path globs to callers who may read the repository root. Do not put sensitive information in withheld path names.
-- `GET /api/v1/tasks`, `/api/v1/ipfs/pins`, and `/api/v1/arweave/anchors` are not repository-gated. Task records include a UCAN token; pin and anchor listings expose object and ref metadata.
+- Task list/get reads (`GET /api/v1/tasks`, `GET /api/v1/tasks/{id}`, and GraphQL `tasks` / `task`) are repository/task-gated through shared visibility collectors and omit `ucan_token`. `/api/v1/ipfs/pins` and `/api/v1/arweave/anchors` are not repository-gated; pin and anchor listings expose object and ref metadata.
 - Changing a repository's visibility controls future serving, but cannot retract ref metadata or configured external pins and anchors already announced while the repository was public. Do not push secrets to an announceable repository.
 - **Impact:** Visibility policies protect the repository and Git content routes they gate, not every metadata endpoint or previously published content.
 - **Remaining boundary:** This read control does not address the independent write-authorization and UCAN-delegation limitations described above.

crates/gitlawb-node/src/api/mod.rs

@@ -22,6 +22,7 @@ pub mod replicas;
 pub mod repos;
 pub mod resolve;
 pub mod stars;
+pub mod task_cursor;
 pub mod tasks;
 pub mod visibility;
 pub mod webhooks;