Tag Archives: Bug-finding

Interview with Matt Might

This post presents an interview I did on March 10th, 2015, with Matt Might, a PL researcher who is an Associate Professor in the School of Computing at the University of Utah.

Matt Might headshot

Matt Might

Matt has made strong scientific contributions to the field of programming languages, and he has done much more. He maintains an incredibly popular blog on wide-ranging topics (13 million pageviews since 2009 on topics from abstract interpretation to how to lose weight to how to be more productive). He has also become deeply committed to supporting people with rare diseases, including his own son, Bertrand, who was the first person diagnosed with NGLY1 deficiency. His work on rare disease propelled him to the White House: He met the President on January 31st, 2015, and he took a position in the Executive Office of the President to accelerate the implementation of the Precision Medicine Initiative on March 21st.

We had an engaging conversation covering all of these topics. It is too long for one post, so this post is the first of two. Continue reading

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Filed under Abstract interpretation, Bioinformatics, Dynamic languages, Interviews, Program Analysis, Science, Scientists

What is memory safety?

I am in the process of putting together a MOOC on software security, which goes live in October. At the moment I’m finishing up material on buffer overflows, format string attacks, and other sorts of vulnerabilities in C. After presenting this material, I plan to step back and say, “What do these errors have in common? They are violations of memory safety.” Then I’ll state the definition of memory safety, say why these vulnerabilities are violations of memory safety, and conversely say why memory safety, e.g., as ensured by languages like Java, prevents them.

No problem, right? Memory safety is a common technical term, so I expected its definition would be easy to find (or derive). But it’s much trickier than I thought.

My goal with this post is to work out a definition of memory safety for C that is semantically clean, rules out code that seems intuitively unsafe, but does not rule out code that seems reasonable. The simpler, and more complete, the definition, the better. My final definition is based on the notion of defined/undefined memory and the use of pointers as capabilities. If you have better ideas, I’d love to know them!

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Filed under PL in practice, Semantics, Software Security

Programming language research for K-16 education (Part II)

In this post, I’ll continue our ongoing discussion of applications of PL research in computer-assisted education. Specifically, I’ll summarize a talk that Loris D’Antoni of Penn gave at this year’s Workshop on Programming Language Technology for Massive Open Online Courses (PLOOC). I was intrigued by this work, and I think a lot of you may be too.

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Filed under Education, MOOCs

Programming language research for K-16 education

At the recent PLDI conference, Armando Solar-Lezama and I organized a workshop called PLOOC: “Programming Language Tools for Massive Open Online Courses.” The high-level goal of the workshop was to discuss ways in which tools coming out of PL research can be used in K-16 education. Over the years, PL researchers have developed many techniques for automating and simplifying the design and analysis of programs. For the most part, these techniques have targeted the professional programmer. However, techniques developed for industrial code can also be applied to student-written programs in computer science courses.

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Filed under Education, MOOCs