Java 11 was released on Sep 25th, 2018. This is the first long-term support release produced under the six-month cadence release model. Besides a huge number of small improvements and bug fixes, the new release contains 17 major enhancements including:
- several updates in the Hotspot and garbage collectors
- new HTTP client
- Unicode 10
- removing the Java EE and CORBA Modules
- local-variable syntax for Lambda parameters
- launch single-file source-code programs
- and finally several security features
Although all these features are pretty cool, let’s focus on security in this post.
Java 11 supports TLS 1.3 protocol which was published in August 2018. During implementing the new TLS protocol, Java security-libs team significantly re-worked Java Secure Sockets Extension (JSSE). I used to work on security-libs in Java for 6 years, so I can tell that was not an easy task for sure. But nevertheless, Java security-libs team delivered TLS 1.3 implementation in Java 11. Great job!
TLS 1.3 standard was finally published in August 2018. The authors tried to address the problems which unfortunately exist in older versions of the TLS protocol. One of the problems is a lack of protection against downgrade attacks.
Code coverage analysis is used in software testing to discover untested pieces of an application. Gathering code coverage data may also be useful for fuzzing. Basically it may help to figure out which parts of a program were not reached during fuzzing. This info can then be used to improve the fuzzer.
Let’s try to gather some code coverage data during fuzzing. As an example, we’re going to test picotls with tlsbunny. Picotls is an implementation of TLS 1.3 protocol written in C, and tlsbunny is a framework for building negative tests and fuzzers for TLS 1.3 implementations. We’re going to use gcov for gathering code coverage data, and lcov for creating a report.
Picotls is a TLS 1.3 implementation written in C. At the moment of writing this post, picotls implements TLS 1.3 draft 26.
I have been experimenting with TLS 1.3 in tlsbunny project. This is a framework for building negative tests and fuzzers for TLS 1.3 implementations. For example, tlsbunny has several simple fuzzers for TLS structures like TLSPlaintext, Handshake, ClientHello, etc. It would not be worse to run those fuzzers against picotls server.