Foreign key label expanding respects table permissions, closes #2178

datasette/app.py

@@ -935,7 +935,7 @@ class Datasette:
             log_sql_errors=log_sql_errors,
         )
 
-    async def expand_foreign_keys(self, database, table, column, values):
+    async def expand_foreign_keys(self, actor, database, table, column, values):
         """Returns dict mapping (column, value) -> label"""
         labeled_fks = {}
         db = self.databases[database]
@@ -949,6 +949,13 @@ class Datasette:
             ][0]
         except IndexError:
             return {}
+        # Ensure user has permission to view the referenced table
+        if not await self.permission_allowed(
+            actor=actor,
+            action="view-table",
+            resource=(database, fk["other_table"]),
+        ):
+            return {}
         label_column = await db.label_column_for_table(fk["other_table"])
         if not label_column:
             return {(fk["column"], value): str(value) for value in values}

datasette/facets.py

@@ -253,7 +253,7 @@ class ColumnFacet(Facet):
                     # Attempt to expand foreign keys into labels
                     values = [row["value"] for row in facet_rows]
                     expanded = await self.ds.expand_foreign_keys(
-                        self.database, self.table, column, values
+                        self.request.actor, self.database, self.table, column, values
                     )
                 else:
                     expanded = {}

datasette/views/table.py

@@ -1144,7 +1144,7 @@ async def table_view_data(
             # Expand them
             expanded_labels.update(
                 await datasette.expand_foreign_keys(
-                    database_name, table_name, column, values
+                    request.actor, database_name, table_name, column, values
                 )
             )
         if expanded_labels:

tests/test_table_html.py

@@ -1204,3 +1204,56 @@ async def test_format_of_binary_links(size, title, length_bytes):
     sql_response = await ds.client.get("/{}".format(db_name), params={"sql": sql})
     assert sql_response.status_code == 200
     assert expected in sql_response.text
+
+
+@pytest.mark.asyncio
+async def test_foreign_key_labels_obey_permissions():
+    ds = Datasette(
+        metadata={
+            "databases": {
+                "foreign_key_labels": {
+                    "tables": {
+                        # Table a is only visible to root
+                        "a": {"allow": {"id": "root"}},
+                    }
+                }
+            }
+        }
+    )
+    db = ds.add_memory_database("foreign_key_labels")
+    await db.execute_write("create table a(id integer primary key, name text)")
+    await db.execute_write("insert into a (id, name) values (1, 'hello')")
+    await db.execute_write(
+        "create table b(id integer primary key, name text, a_id integer references a(id))"
+    )
+    await db.execute_write("insert into b (id, name, a_id) values (1, 'world', 1)")
+    # Anonymous user can see table b but not table a
+    blah = await ds.client.get("/foreign_key_labels.json")
+    anon_a = await ds.client.get("/foreign_key_labels/a.json?_labels=on")
+    assert anon_a.status_code == 403
+    anon_b = await ds.client.get("/foreign_key_labels/b.json?_labels=on")
+    assert anon_b.status_code == 200
+    # root user can see both
+    cookies = {"ds_actor": ds.sign({"a": {"id": "root"}}, "actor")}
+    root_a = await ds.client.get(
+        "/foreign_key_labels/a.json?_labels=on", cookies=cookies
+    )
+    assert root_a.status_code == 200
+    root_b = await ds.client.get(
+        "/foreign_key_labels/b.json?_labels=on", cookies=cookies
+    )
+    assert root_b.status_code == 200
+    # Labels should have been expanded for root
+    assert root_b.json() == {
+        "ok": True,
+        "next": None,
+        "rows": [{"id": 1, "name": "world", "a_id": {"value": 1, "label": "hello"}}],
+        "truncated": False,
+    }
+    # But not for anon
+    assert anon_b.json() == {
+        "ok": True,
+        "next": None,
+        "rows": [{"id": 1, "name": "world", "a_id": 1}],
+        "truncated": False,
+    }