s3vectors: reject empty boolean-operator lists and sub-objects in filters (#12220)

* s3vectors: reject empty boolean-operator lists and sub-objects in filters

An empty $and/$or list or a nested empty object rendered '()'' — invalid
SQL surfaced as an engine error instead of a clean ValidationException.

* s3vectors: reject field operator objects with no operators

weed/s3api/s3vectors/handlers.go

@@ -1532,6 +1532,9 @@ func filterExpr(filter map[string]interface{}) (string, error) {
 			if !ok {
 				return "", fmt.Errorf("%s expects a list", key)
 			}
+			if len(sub) == 0 {
+				return "", fmt.Errorf("%s expects a non-empty list", key)
+			}
 			exprs := make([]string, 0, len(sub))
 			for _, item := range sub {
 				m, ok := item.(map[string]interface{})
@@ -1542,6 +1545,9 @@ func filterExpr(filter map[string]interface{}) (string, error) {
 				if err != nil {
 					return "", err
 				}
+				if e == "" {
+					return "", fmt.Errorf("%s expects non-empty objects", key)
+				}
 				exprs = append(exprs, e)
 			}
 			joiner := " AND "
@@ -1684,6 +1690,9 @@ func fieldClause(field string, cond interface{}) (string, error) {
 				return "", fmt.Errorf("unsupported operator %s", op)
 			}
 		}
+		if len(parts) == 0 {
+			return "", fmt.Errorf("%s expects at least one operator", field)
+		}
 		return strings.Join(parts, " AND "), nil
 	default:
 		lit, err := sqlLiteral(cond)

weed/s3api/s3vectors/handlers_test.go

@@ -336,12 +336,19 @@ func TestTranslateFilter(t *testing.T) {
 	}
 
 	for name, filter := range map[string]map[string]interface{}{
-		"unknown operator":  {"k": map[string]interface{}{"$bogus": "v"}},
-		"exists non-bool":   {"k": map[string]interface{}{"$exists": "yes"}},
-		"range non-number":  {"k": map[string]interface{}{"$gt": "v"}},
-		"in non-list":       {"k": map[string]interface{}{"$in": "v"}},
-		"top-level bad op":  {"$bogus": []interface{}{}},
-		"nested bad member": {"$and": []interface{}{"x"}},
+		"unknown operator":   {"k": map[string]interface{}{"$bogus": "v"}},
+		"exists non-bool":    {"k": map[string]interface{}{"$exists": "yes"}},
+		"range non-number":   {"k": map[string]interface{}{"$gt": "v"}},
+		"in non-list":        {"k": map[string]interface{}{"$in": "v"}},
+		"top-level bad op":   {"$bogus": []interface{}{}},
+		"nested bad member":  {"$and": []interface{}{"x"}},
+		"empty and list":     {"$and": []interface{}{}},
+		"empty or list":      {"$or": []interface{}{}},
+		"empty sub-object":   {"$and": []interface{}{map[string]interface{}{}}},
+		"empty operators":    {"k": map[string]interface{}{}},
+		"empty among fields": {"k": map[string]interface{}{}, "j": "1"},
+		"empty under and": {"$and": []interface{}{map[string]interface{}{
+			"k": map[string]interface{}{}, "j": map[string]interface{}{}}}},
 	} {
 		if _, err := translateFilter(filter); err == nil {
 			t.Fatalf("%s should fail", name)