Merge pull request #113 from cipherstash/encrypted-columns-with-explicit-null-values

Correctly cast and handle nulls for order ops

Author: tobyhede

src/encrypted/casts.sql

@@ -9,6 +9,10 @@
 CREATE FUNCTION eql_v2.to_encrypted(data jsonb)
 RETURNS public.eql_v2_encrypted AS $$
 BEGIN
+    IF data IS NULL THEN
+        RETURN NULL;
+    END IF;
+
     RETURN ROW(data)::public.eql_v2_encrypted;
 END;
 $$ LANGUAGE plpgsql;
@@ -28,6 +32,10 @@ CREATE CAST (jsonb AS public.eql_v2_encrypted)
 CREATE FUNCTION eql_v2.to_encrypted(data text)
 RETURNS public.eql_v2_encrypted AS $$
 BEGIN
+    IF data IS NULL THEN
+        RETURN NULL;
+    END IF;
+
     RETURN ROW(data::jsonb)::public.eql_v2_encrypted;
 END;
 $$ LANGUAGE plpgsql;
@@ -48,6 +56,10 @@ CREATE CAST (text AS public.eql_v2_encrypted)
 CREATE FUNCTION eql_v2.to_jsonb(e public.eql_v2_encrypted)
 RETURNS jsonb AS $$
 BEGIN
+    IF e IS NULL THEN
+        RETURN NULL;
+    END IF;
+
     RETURN e.data;
 END;
 $$ LANGUAGE plpgsql;

src/operators/operator_class.sql

@@ -22,6 +22,18 @@ AS $$
     a_ore := eql_v2.ore_block_u64_8_256(a);
     b_ore := eql_v2.ore_block_u64_8_256(b);
 
+    IF a_ore IS NULL AND b_ore IS NULL THEN
+      RETURN 0;
+    END IF;
+
+    IF a_ore IS NULL THEN
+      RETURN -1;
+    END IF;
+
+    IF b_ore IS NULL THEN
+      RETURN 1;
+    END IF;
+
     RETURN eql_v2.compare_ore_array(a_ore.terms, b_ore.terms);
   END;
 $$ LANGUAGE plpgsql;

src/operators/order_by_test.sql

@@ -72,4 +72,76 @@ DECLARE
         '43');
 
   END;
-$$ LANGUAGE plpgsql;
+$$ LANGUAGE plpgsql;
+
+
+SELECT create_table_with_encrypted();
+
+--
+-- ORE - ORDER BY NULL handling
+--
+DO $$
+DECLARE
+    e eql_v2_encrypted;
+    ore_term eql_v2_encrypted;
+  BEGIN
+
+      -- Insert records with NULL values
+      -- record with ID=1 and e=NULL
+      INSERT INTO encrypted(e) VALUES (NULL::jsonb::eql_v2_encrypted);
+
+
+      -- Pull records from the ore table and insert
+      SELECT ore.e FROM ore WHERE id = 42 INTO ore_term;
+      -- record with ID=2 and e=42
+      INSERT INTO encrypted(e) VALUES (ore_term);
+
+
+      SELECT ore.e FROM ore WHERE id = 3 INTO ore_term;
+      -- record with ID=3 and e=3
+      INSERT INTO encrypted(e) VALUES (ore_term);
+
+
+      -- record with ID=4 and e=NULL
+      INSERT INTO encrypted(e) VALUES (NULL::jsonb::eql_v2_encrypted);
+
+      PERFORM assert_result(
+        'ORDER BY encrypted',
+        format('SELECT id FROM encrypted ORDER BY e'),
+        '3');
+
+      PERFORM assert_result(
+        'ORDER BY encrypted ASC',
+        format('SELECT id FROM encrypted ORDER BY e ASC'),
+        '3');
+
+      PERFORM assert_result(
+        'ORDER BY eql_v2.order_by(e) ASC NULLS FIRST',
+        format('SELECT id FROM encrypted ORDER BY e ASC NULLS FIRST'),
+        '1');
+
+      PERFORM assert_result(
+        'ORDER BY eql_v2.order_by(e) ASC NULLS LAST',
+        format('SELECT id FROM encrypted ORDER BY e ASC NULLS LAST'),
+        '3');
+
+      -- NULLS FIRST when DESC
+      PERFORM assert_result(
+        'ORDER BY encrypted DESC',
+        format('SELECT id FROM encrypted ORDER BY e DESC'),
+        '1');
+
+      PERFORM assert_result(
+        'ORDER BY eql_v2.order_by(e) DESC NULLS FIRST',
+        format('SELECT id FROM encrypted ORDER BY e DESC NULLS FIRST'),
+        '1');
+
+      PERFORM assert_result(
+        'ORDER BY eql_v2.order_by(e) DESC NULLS LAST',
+        format('SELECT id FROM encrypted ORDER BY e DESC NULLS LAST'),
+        '2');
+
+  END;
+$$ LANGUAGE plpgsql;
+
+PERFORM drop_table_with_encrypted();

src/ore_block_u64_8_256/functions.sql

@@ -54,6 +54,10 @@ CREATE FUNCTION eql_v2.ore_block_u64_8_256(val jsonb)
   IMMUTABLE STRICT PARALLEL SAFE
 AS $$
 	BEGIN
+    IF val IS NULL THEN
+      RETURN NULL;
+    END IF;
+
     IF val ? 'ob' THEN
       RETURN eql_v2.jsonb_array_to_ore_block_u64_8_256(val->'ob');
     END IF;