5,930 research outputs found
A formally verified compiler back-end
This article describes the development and formal verification (proof of
semantic preservation) of a compiler back-end from Cminor (a simple imperative
intermediate language) to PowerPC assembly code, using the Coq proof assistant
both for programming the compiler and for proving its correctness. Such a
verified compiler is useful in the context of formal methods applied to the
certification of critical software: the verification of the compiler guarantees
that the safety properties proved on the source code hold for the executable
compiled code as well
Secure Compilation (Dagstuhl Seminar 18201)
Secure compilation is an emerging field that puts together advances in
security, programming languages, verification, systems, and hardware
architectures in order to devise secure compilation chains that
eliminate many of today\u27s vulnerabilities.
Secure compilation aims to protect a source language\u27s abstractions in
compiled code, even against low-level attacks.
For a concrete example, all modern languages provide a notion of
structured control flow and an invoked procedure is expected to return
to the right place.
However, today\u27s compilation chains (compilers, linkers, loaders,
runtime systems, hardware) cannot efficiently enforce this
abstraction: linked low-level code can call and return to arbitrary
instructions or smash the stack, blatantly violating the high-level
abstraction.
The emerging secure compilation community aims to address such
problems by devising formal security criteria, efficient enforcement
mechanisms, and effective proof techniques.
This seminar strived to take a broad and inclusive view of secure
compilation and to provide a forum for discussion on the topic. The
goal was to identify interesting research directions and open
challenges by bringing together people working on building secure
compilation chains, on developing proof techniques and verification
tools, and on designing security mechanisms
A Linear First-Order Functional Intermediate Language for Verified Compilers
We present the linear first-order intermediate language IL for verified
compilers. IL is a functional language with calls to a nondeterministic
environment. We give IL terms a second, imperative semantic interpretation and
obtain a register transfer language. For the imperative interpretation we
establish a notion of live variables. Based on live variables, we formulate a
decidable property called coherence ensuring that the functional and the
imperative interpretation of a term coincide. We formulate a register
assignment algorithm for IL and prove its correctness. The algorithm translates
a functional IL program into an equivalent imperative IL program. Correctness
follows from the fact that the algorithm reaches a coherent program after
consistently renaming local variables. We prove that the maximal number of live
variables in the initial program bounds the number of different variables in
the final coherent program. The entire development is formalized in Coq.Comment: Addressed comments from reviewers (ITP 2015): (1) Added discussion of
a paper in related work (2) Added definition of renamed-apart in appendix (3)
Formulation changes in a coupe of place
Formal Verification of Security Protocol Implementations: A Survey
Automated formal verification of security protocols has been mostly focused on analyzing high-level abstract models which, however, are significantly different from real protocol implementations written in programming languages. Recently, some researchers have started investigating techniques that bring automated formal proofs closer to real implementations. This paper surveys these attempts, focusing on approaches that target the application code that implements protocol logic, rather than the libraries that implement cryptography. According to these approaches, libraries are assumed to correctly implement some models. The aim is to derive formal proofs that, under this assumption, give assurance about the application code that implements the protocol logic. The two main approaches of model extraction and code generation are presented, along with the main techniques adopted for each approac
On-stack replacement, distilled
On-stack replacement (OSR) is essential technology for adaptive optimization, allowing changes to code actively executing in a managed runtime. The engineering aspects of OSR are well-known among VM architects, with several implementations available to date. However, OSR is yet to be explored as a general means to transfer execution between related program versions, which can pave the road to unprecedented applications that stretch beyond VMs. We aim at filling this gap with a constructive and provably correct OSR framework, allowing a class of general-purpose transformation functions to yield a special-purpose replacement. We describe and evaluate an implementation of our technique in LLVM. As a novel application of OSR, we present a feasibility study on debugging of optimized code, showing how our techniques can be used to fix variables holding incorrect values at breakpoints due to optimizations
ARM2GC: Succinct Garbled Processor for Secure Computation
We present ARM2GC, a novel secure computation framework based on Yao's
Garbled Circuit (GC) protocol and the ARM processor. It allows users to develop
privacy-preserving applications using standard high-level programming languages
(e.g., C) and compile them using off-the-shelf ARM compilers (e.g., gcc-arm).
The main enabler of this framework is the introduction of SkipGate, an
algorithm that dynamically omits the communication and encryption cost of the
gates whose outputs are independent of the private data. SkipGate greatly
enhances the performance of ARM2GC by omitting costs of the gates associated
with the instructions of the compiled binary, which is known by both parties
involved in the computation. Our evaluation on benchmark functions demonstrates
that ARM2GC not only outperforms the current GC frameworks that support
high-level languages, it also achieves efficiency comparable to the best prior
solutions based on hardware description languages. Moreover, in contrast to
previous high-level frameworks with domain-specific languages and customized
compilers, ARM2GC relies on standard ARM compiler which is rigorously verified
and supports programs written in the standard syntax.Comment: 13 page
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