Harden closed-advisory fixes (#16409)

## Summary
- harden reopened advisory fixes across REST connector, invoke, document
downloads, and markdown rendering
- add targeted regression coverage for redirect-safe SSRF handling,
invoke SSRF checks, document access control, and markdown sanitization
- verify each referenced GHSA against the original GitHub advisory text
and align the closed-advisory plan with the implemented remediation

## What changed
- add tenant access checks to document download endpoints to avoid
cross-tenant document disclosure
- add per-hop SSRF validation, DNS pinning, redirect handling, and
redirect limits to the REST API connector
- ensure invoke requests validate and pin the resolved host and never
follow redirects implicitly
- keep the generic rate-limited request path wrapped, not just GET and
POST helpers
- sanitize markdown HTML before rendering in the highlight markdown
component

## Validation
- `cd web && npm test -- --runInBand
src/components/highlight-markdown/__tests__/index.test.tsx`
- `.venv/bin/python -m pytest -q
test/unit_test/data_source/test_rest_api_connector.py`
- targeted `test/testcases/test_web_api/...` unit additions were
reviewed, but the suite cannot be executed end-to-end in this
environment because parent `test/testcases/conftest.py` requires a local
service on `127.0.0.1:9380`

## Notes
- all GHSA entries referenced by the plan were checked against the
original GitHub advisory text, not sampled
- the closed-advisory plan document was updated locally during review,
but is intentionally not included in this PR

test/testcases/restful_api/test_document_raw_routes.py

@@ -45,7 +45,7 @@ def test_document_download_by_id_invalid_id_contract(rest_client):
     assert res.status_code == 200
     payload = res.json()
     assert payload["code"] == 102, payload
-    assert payload["message"] == "The dataset not own the document invalid_document_id.", payload
+    assert payload["message"] == "Document not found!", payload
 
 
 @pytest.mark.p2

test/testcases/restful_api/test_documents.py

@@ -1503,14 +1503,14 @@ def test_documents_download_requires_auth_and_invalid_id_contract(rest_client, c
     assert invalid_doc_res.status_code == 200
     invalid_doc_payload = invalid_doc_res.json()
     assert invalid_doc_payload["code"] == 102, invalid_doc_payload
-    assert "The dataset not own the document invalid_document_id." in invalid_doc_payload["message"], invalid_doc_payload
+    assert invalid_doc_payload["message"] == "Document not found!", invalid_doc_payload
 
     invalid_dataset_path = tmp_path / "invalid_dataset_download.txt"
     invalid_dataset_res = _download_document_to_file(rest_client, "invalid_dataset_id", document_id, invalid_dataset_path)
     assert invalid_dataset_res.status_code == 200
     invalid_dataset_payload = invalid_dataset_res.json()
     assert invalid_dataset_payload["code"] == 102, invalid_dataset_payload
-    assert f"The dataset not own the document {document_id}." in invalid_dataset_payload["message"], invalid_dataset_payload
+    assert invalid_dataset_payload["message"] == "Document not found!", invalid_dataset_payload
 
 
 @pytest.mark.p2

test/testcases/test_web_api/test_canvas_app/test_invoke_component_unit.py

@@ -271,3 +271,37 @@ def test_header_variable_with_put(monkeypatch):
     monkeypatch.setattr(module.requests, "put", mock_put)
     invoke._invoke()
     assert mock_put.call_args[1]["headers"]["Authorization"] == "Bearer put_token"
+
+
+@pytest.mark.p2
+def test_invoke_rejects_private_url(monkeypatch):
+    module = _load_invoke_module(monkeypatch)
+    invoke = _make_invoke(module, url="http://127.0.0.1:22")
+    monkeypatch.setattr(
+        module,
+        "assert_url_is_safe",
+        MagicMock(side_effect=ValueError("URL resolves to a non-public address")),
+    )
+    # Coderabbit MAJOR #3486038793: _build_url() is now inside the retry
+    # try/except block, so the ValueError from assert_url_is_safe is caught
+    # and the message is stored in _ERROR via the standard error path.
+    invoke._invoke()
+    assert "non-public address" in invoke._param.outputs["_ERROR"]
+
+
+@pytest.mark.p2
+def test_invoke_pins_dns_and_disables_redirects(monkeypatch):
+    module = _load_invoke_module(monkeypatch)
+    invoke = _make_invoke(module, url="http://example.com")
+    pin_ctx = MagicMock()
+    pin_ctx.__enter__ = MagicMock(return_value=None)
+    pin_ctx.__exit__ = MagicMock(return_value=None)
+    monkeypatch.setattr(module, "assert_url_is_safe", MagicMock(return_value=("example.com", "93.184.216.34")))
+    monkeypatch.setattr(module, "pin_dns", MagicMock(return_value=pin_ctx))
+    mock_get = MagicMock(return_value=SimpleNamespace(text="ok"))
+    monkeypatch.setattr(module.requests, "get", mock_get)
+
+    invoke._invoke()
+
+    module.pin_dns.assert_called_once_with("example.com", "93.184.216.34")
+    assert mock_get.call_args[1]["allow_redirects"] is False

test/testcases/test_web_api/test_document_app/test_document_metadata.py

@@ -450,6 +450,23 @@ class TestDocumentMetadataUnit:
         assert res["code"] == 500
         assert "download boom" in res["message"]
 
+    def test_download_document_rejects_other_tenant_unit(self, document_rest_api_module, monkeypatch):
+        module = document_rest_api_module
+        monkeypatch.setattr(module.DocumentService, "accessible", lambda _doc_id, _user_id: False)
+
+        res = _run(module.download_document("doc1"))
+        assert res["code"] == RetCode.DATA_ERROR
+        assert "Document not found!" in res["message"]
+
+    def test_dataset_document_download_rejects_other_tenant_unit(self, document_rest_api_module, monkeypatch):
+        module = document_rest_api_module
+        monkeypatch.setattr(module.KnowledgebaseService, "accessible", lambda kb_id, user_id: False)
+        monkeypatch.setattr(module.DocumentService, "accessible", lambda _doc_id, _user_id: True)
+
+        res = _run(module.download("kb1", "doc1"))
+        assert res["code"] == RetCode.DATA_ERROR
+        assert "Document not found!" in res["message"]
+
     @pytest.mark.p2
     def test_get_document_image_content_type_from_object_extension_unit(self, document_app_module, monkeypatch):
         module = document_app_module