8.3 Connector/ODBC and the Application Both Use OpenSSL

If Connector/ODBC is connecting securely with the MySQL server and the application using the connection makes calls itself to an OpenSSL library, the application might then fail, as two copies of the OpenSSL library will then be in use.

Note

Connector/ODBC 8.0 and higher link to OpenSSL dynamically while earlier Connector/ODBC versions link to OpenSSL statically. This solves problems related to using two OpenSSL copies from the same application.

Note

The TLSv1.0 and TLSv1.1 connection protocols were deprecated in Connector/ODBC 8.0.26 and removed in version 8.0.28.

Note

See also the tls-versions connection option.

To prevent the issue, in your application, do not allow OpenSSL initialization in one thread and the opening of an Connector/ODBC connection in another thread (which also initializes openSSL) to happen simultaneously. For example, use a mutex to ensure synchronization between SQLDriverConnect() or SQLConnect() calls and openSSL initialization. In addition to that, implement the following if possible:

Use a build of Connector/ODBC that links (statically or dynamically) to a version of the libmysqlclient library that is in turn dynamically linked to the same OpenSSL library that the application calls.
When creating a build of Connector/ODBC that links (statically or dynamically) to a version of the libmysqlclient library that is in turn statically linked to an OpenSSL library, do NOT export OpenSSL symbols in your build. That prevents incorrect resolution of application symbols; however, that does not prevent other issues that come with running two copies of OpenSSL code within a single application.