Database connectors are widely used in many applications to facilitate flexible and convenient database interactions. Potential vulnerabilities in database connectors can lead to various abnormal behaviors within applications, such as returning incorrect results or experiencing unexpected connection interruption. However, existing fuzzing works cannot be directly applied to testing database connectors as they mainly focus on SQL generation and use a small subset of database connector interfaces to execute SQLs. Due to a lack of domain knowledge, automated test case generation also struggles to generate complex test cases that explore connectors’ deep logic.

The main challenge in testing database connectors is to generate semantically correct test cases that can trigger a wide range of connector state transitions. To address that, we propose CONI, a framework designed for detecting logic bugs of database connectors with state-aware test case generation. First, we define the database connector state model by analyzing the corresponding specification. Building upon this model, CONI generates interface call sequences within test cases to encompass more connector state transitions. After that, CONI generates suitable parameter values based on the parameter information and contextual information collected during runtime. Then the test cases are executed on a target and a reference database connector. Inconsistent results indicate potential logic bugs. We evaluate CONI on 5 widely-used JDBC database connectors, namely MySQL Connector/J, MariaDB Connector/J, AWS JDBC Driver for MySQL, PGJDBC NG, and PostgreSQL JDBC Driver. In total, CONI successfully detected 44 previously unknown bugs, of which 34 have been confirmed.