Securing Verified IO Programs Against Unverified Code in F*
We introduce SCIO*, a formally secure compilation framework for statically verified partial programs performing input-output (IO). The source language is an F* subset in which a verified program interacts with its IO-performing context via a higher-order interface that includes refinement types as well as pre- and post-conditions about past IO events. The target language is a smaller F* subset in which the compiled program is linked with an adversarial context that has an interface without refinement types, pre-conditions, or concrete post-conditions. To bridge this interface gap and make compilation and linking secure we propose a formally verified combination of higher-order contracts and reference monitoring for recording and controlling IO operations. Compilation uses contracts to convert the logical assumptions the program makes about the context into dynamic checks on each context-program boundary crossing. These boundary checks can depend on information about past IO events stored in the state of the monitor. But these checks cannot stop the adversarial target context before it performs dangerous IO operations. Therefore linking in SCIO* additionally forces the context to perform all IO actions via a secure IO library, which uses reference monitoring to dynamically enforce an access control policy before each IO operation. We prove in F* that SCIO* soundly enforces a global trace property for the compiled verified program linked with the untrusted context. Moreover, we prove in F* that SCIO* satisfies by construction Robust Relational Hyperproperty Preservation, a very strong secure compilation criterion. Finally, we illustrate SCIO* at work on a simple web server example.
Fri 19 JanDisplayed time zone: London change
16:50 - 18:10 | Gradual Typing and VerificationPOPL at Kelvin Lecture Chair(s): Ronald Garcia University of British Columbia | ||
16:50 20mTalk | Securing Verified IO Programs Against Unverified Code in F* POPL Cezar-Constantin Andrici MPI-SP, Stefan Ciobaca Alexandru Ioan Cuza University of Iasi, Cătălin Hriţcu MPI-SP, Guido Martínez Microsoft Research, Exequiel Rivas Tallinn University of Technology, Éric Tanter University of Chile, Théo Winterhalter INRIA Saclay Pre-print | ||
17:10 20mTalk | Sound Gradual Verification with Symbolic Execution POPL Conrad Zimmerman Brown University, Jenna DiVincenzo (Wise) Purdue University, Jonathan Aldrich Carnegie Mellon University | ||
17:30 20mTalk | Type-based Gradual Typing Performance Optimization POPL | ||
17:50 20mTalk | Total Type Error Localization and Recovery with HolesDistinguished Paper POPL Eric Zhao University of Michigan, Raef Maroof University of Michigan, Anand Dukkipati University of Michigan, Andrew Blinn University of Michigan, Zhiyi Pan University of Michigan, Cyrus Omar University of Michigan |