Biblio

Sandboxes are increasingly important building materials for secure software systems. In recognition of their potential to improve the security posture of many systems at various points in the development lifecycle, researchers have spent the last several decades developing, improving, and evaluating sandboxing techniques. What has been done in this space? Where are the barriers to advancement? What are the gaps in these efforts? We systematically analyze a decade of sandbox research from five top-tier security and systems conferences using qualitative content analysis, statistical clustering, and graph-based metrics to answer these questions and more. We find that the term “sandbox” currently has no widely accepted or acceptable definition. We use our broad scope to propose the first concise and comprehensive definition for “sandbox” that consistently encompasses research sandboxes. We learn that the sandboxing landscape covers a range of deployment options and policy enforcement techniques collectively capable of defending diverse sets of components while mitigating a wide range of vulnerabilities. Researchers consistently make security, performance, and applicability claims about their sandboxes and tend to narrowly define the claims to ensure they can be evaluated. Those claims are validated using multi-faceted strategies spanning proof, analytical analysis, benchmark suites, case studies, and argumentation. However, we find two cases for improvement: (1) the arguments researchers present are often ad hoc and (2) sandbox usability is mostly uncharted territory. We propose ways to structure arguments to ensure they fully support their corresponding claims and suggest lightweight means of evaluating sandbox usability.

Programming languages often include specialized syntax for common datatypes e.g. lists and some also build in support for specific specialized datatypes e.g. regular expressions, but user-defined types must use general-purpose syntax. Frustration with this causes developers to use strings, rather than structured data, with alarming frequency, leading to correctness, performance, security, and usability issues. Allowing library providers to modularly extend a language with new syntax could help address these issues. Unfortunately, prior mechanisms either limit expressiveness or are not safely composable: individually unambiguous extensions can still cause ambiguities when used together. We introduce type-specific languages TSLs: logic associated with a type that determines how the bodies of generic literals, able to contain arbitrary syntax, are parsed and elaborated, hygienically. The TSL for a type is invoked only when a literal appears where a term of that type is expected, guaranteeing non-interference. We give evidence supporting the applicability of this approach and formally specify it with a bidirectionally typed elaboration semantics for the Wyvern programming language.

Domain-specific languages improve ease-of-use, expressiveness and verifiability, but defining and using different DSLs within a single application remains difficult. We introduce an approach for embedded DSLs where 1) whitespace delimits DSL-governed blocks, and 2) the parsing and type checking phases occur in tandem so that the expected type of the block determines which domain-specific parser governs that block. We argue that this approach occupies a sweet spot, providing high expressiveness and ease-of-use while maintaining safe composability. We introduce the design, provide examples and describe an ongoing implementation of this strategy in the Wyvern programming language. We also discuss how a more conventional keyword-directed strategy for parsing of DSLs can arise as a special case of this type-directed strategy. 

The simplest and purest practical object-oriented language designs today are seen in dynamically-typed languages, such as Smalltalk and Self. Static types, however, have potential benefits for productivity, security, and reasoning about programs. In this paper, we describe the design of Wyvern, a statically typed, pure object-oriented language that attempts to retain much of the simplicity and expressiveness of these iconic designs.

Our goals lead us to combine pure object-oriented and functional abstractions in a simple, typed setting. We present a foundational object-based language that we believe to be as close as one can get to simple typed lambda calculus while keeping object-orientation. We show how this foundational language can be translated to the typed lambda calculus via standard encodings. We then define a simple extension to this language that introduces classes and show that classes are no more than sugar for the foundational object-based language. Our future intention is to demonstrate that modules and other object-oriented features can be added to our language as not more than such syntactical extensions while keeping the object-oriented core as pure as possible.

The design of Wyvern closely follows both historical and modern ideas about the essence of object-orientation, suggesting a new way to think about a minimal, practical, typed core language for objects.