scholarly journals Verification of MILS Partition Scheduling Module Using Layered Methods

2021 ◽  
pp. 45-52
Author(s):  
Yang Gao ◽  
◽  
Xia Yang ◽  
Wensheng Guo ◽  
Xiutai Lu
Keyword(s):  
Operating Systems ◽  
Data Structures ◽  
Data Representation ◽  
Separation Logic ◽  
Proof Assistant ◽  
The Coq Proof Assistant ◽  
Function Calls ◽  
Coq Proof Assistant ◽  
Data Structures And Algorithms ◽  
Secure Strategies

MILS partition scheduling module ensures isolation of data between different domains completely by enforcing secure strategies. Although small in size, it involves complicated data structures and algorithms that make monolithic verification of the scheduling module difficult using traditional verification logic (e.g., separation logic). In this paper, we simplify the verification task by dividing data representation and data operation into different layers and then to link them together by composing a series of abstraction layers. The layered method also supports function calls from higher implementation layers into lower abstraction layers, allowing us to ignore implementation details in the lower implementation layers. Using this methodology, we have verified a realistic MILS partition scheduling module that can schedule operating systems (Ubuntu 14.04, VxWorks 6.8 and RTEMS 11.0) located in different domains. The entire verification has been mechanized in the Coq Proof Assistant.

scholarly journals Iris from the ground up: A modular foundation for higher-order concurrent separation logic

2018 ◽  
Vol 28 ◽  
Author(s):  
RALF JUNG ◽  
ROBBERT KREBBERS ◽  
JACQUES-HENRI JOURDAN ◽  
ALEŠ BIZJAK ◽  
LARS BIRKEDAL ◽  
...  
Keyword(s):  
First Principles ◽  
Higher Order ◽  
Separation Logic ◽  
Complete Picture ◽  
Proof Assistant ◽  
The Coq Proof Assistant ◽  
Coq Proof Assistant ◽  
Concurrent Separation Logic ◽  
Over Time

Iris is a framework for higher-order concurrent separation logic, which has been implemented in the Coq proof assistant and deployed very effectively in a wide variety of verification projects. Iris was designed with the express goal of simplifying and consolidating the foundations of modern separation logics, but it has evolved over time, and the design and semantic foundations of Iris itself have yet to be fully written down and explained together properly in one place. Here, we attempt to fill this gap, presenting a reasonably complete picture of the latest version of Iris (version 3.1), from first principles and in one coherent narrative.

scholarly journals Theorems for free from separation logic specifications

2021 ◽  
Vol 5 (ICFP) ◽  
pp. 1-29
Author(s):  
Lars Birkedal ◽  
Thomas Dinsdale-Young ◽  
Armaël Guéneau ◽  
Guilhem Jaber ◽  
Kasper Svendsen ◽  
...  
Keyword(s):  
Higher Order ◽  
Separation Logic ◽  
Proof Assistant ◽  
The Coq Proof Assistant ◽  
Coq Proof Assistant ◽  
Interaction Traces ◽  
Concurrent Separation Logic

Separation logic specifications with abstract predicates intuitively enforce a discipline that constrains when and how calls may be made between a client and a library. Thus a separation logic specification of a library intuitively enforces a protocol on the trace of interactions between a client and the library. We show how to formalize this intuition and demonstrate how to derive "free theorems" about such interaction traces from abstract separation logic specifications. We present several examples of free theorems. In particular, we prove that a so-called logically atomic concurrent separation logic specification of a concurrent module operation implies that the operation is linearizable. All the results presented in this paper have been mechanized and formally proved in the Coq proof assistant using the Iris higher-order concurrent separation logic framework.

scholarly journals Homotopy limits in type theory

2015 ◽  
Vol 25 (5) ◽  
pp. 1040-1070 ◽  
Author(s):  
JEREMY AVIGAD ◽  
KRZYSZTOF KAPULKIN ◽  
PETER LEFANU LUMSDAINE
Keyword(s):  
Homotopy Type ◽  
Systematic Study ◽  
Type Theory ◽  
Proof Assistant ◽  
Classical Approach ◽  
Homotopy Type Theory ◽  
The Coq Proof Assistant ◽  
Homotopy Limits ◽  
Coq Proof Assistant

Working in homotopy type theory, we provide a systematic study of homotopy limits of diagrams over graphs, formalized in the Coq proof assistant. We discuss some of the challenges posed by this approach to the formalizing homotopy-theoretic material. We also compare our constructions with the more classical approach to homotopy limits via fibration categories.

Every bit counts: The binary representation of typed data and programs

2012 ◽  
Vol 22 (4-5) ◽  
pp. 529-573 ◽  
Author(s):  
ANDREW J. KENNEDY ◽  
DIMITRIOS VYTINIOTIS
Keyword(s):  
Binary Data ◽  
General Framework ◽  
Binary Representation ◽  
Proof Assistant ◽  
A Value ◽  
The Coq Proof Assistant ◽  
Binary Encoding ◽  
Coq Proof Assistant ◽  
Definition Of ◽  
Formal Properties

AbstractWe show how the binary encoding and decoding of typed data and typed programs can be understood, programmed and verified with the help of question–answer games. The encoding of a value is determined by the yes/no answers to a sequence of questions about that value; conversely, decoding is the interpretation of binary data as answers to the same question scheme. We introduce a general framework for writing and verifying game-based codecs. We present games in Haskell for structured, recursive, polymorphic and indexed types, building up to a representation of well-typed terms in the simply-typed λ-calculus with polymorphic constants. The framework makes novel use of isomorphisms between types in the definition of games. The definition of isomorphisms together with additional simple properties make it easy to prove that codecs derived from games never encode two distinct values using the same code, never decode two codes to the same value and interpret any bit sequence as a valid code for a value or as a prefix of a valid code. Formal properties of the framework have been proved using the Coq proof assistant.

scholarly journals Skipping the binder bureaucracy with mixed embeddings in a semantics course (functional pearl)

2021 ◽  
Vol 5 (ICFP) ◽  
pp. 1-28
Author(s):  
Adam Chlipala
Keyword(s):  
Order Reduction ◽  
Separation Logic ◽  
Variable Binding ◽  
Type Checking ◽  
Session Types ◽  
The Coq Proof Assistant ◽  
Reduction Program ◽  
Coq Proof Assistant ◽  
Big Ideas ◽  
Concurrent Separation Logic

Rigorous reasoning about programs calls for some amount of bureaucracy in managing details like variable binding, but, in guiding students through big ideas in semantics, we might hope to minimize the overhead. We describe our experiment introducing a range of such ideas, using the Coq proof assistant, without any explicit representation of variables, instead using a higher-order syntax encoding that we dub "mixed embedding": it is neither the fully explicit syntax of deep embeddings nor the syntax-free programming of shallow embeddings. Marquee examples include different takes on concurrency reasoning, including in the traditions of model checking (partial-order reduction), program logics (concurrent separation logic), and type checking (session types) -- all presented without any side conditions on variables.

scholarly journals A formal approach for the verification of the permission-based security model of Android

2018 ◽  
Vol 21 (2) ◽  
Author(s):  
Carlos Luna ◽  
Gustavo Betarte ◽  
Juan Campo ◽  
Camila Sanz ◽  
Maximiliano Cristiá ◽  
...  
Keyword(s):  
Formal Specification ◽  
Control Policy ◽  
Proof Assistant ◽  
Security Model ◽  
Access Control Policy ◽  
Formal Approach ◽  
Fundamental Properties ◽  
The Coq Proof Assistant ◽  
Coq Proof Assistant ◽  
Security Properties

This article reports on our experiences in applying formal methods to verify the security mechanisms of Android. We have developed a comprehensive formal specification of Android's permission model, which has been used to state and prove properties that establish expected behavior of the procedures that enforce the defined access control policy. We are also interested in providing guarantees concerning actual implementations of the mechanisms. Therefore we are following a verification approach that combines the use of idealized models, on which fundamental properties are formally verified, with testing of actual implementations using lightweight model-based techniques. We describe the formalized model, present security properties that have been proved using the Coq proof assistant and propose the use of a certified algorithm for performing verification activities such as monitoring of actual implementations of the platform and also as a testing oracle.

scholarly journals Ownership and Immutability in Coq

2021 ◽  
Author(s):  
◽  
Julian Mackay
Keyword(s):  
Programming Languages ◽  
Management System ◽  
Type Systems ◽  
Formal Proof ◽  
Proof Assistant ◽  
Significant Issue ◽  
The Coq Proof Assistant ◽  
Coq Proof Assistant

<p>A significant issue in modern programming languages is unsafe aliasing. Modern type systems have attempted to address this in two prominent ways; immutability and ownership, and often a combination of the two [4][17]. The goal of this thesis is to formalise Immutability and Ownership using the Coq Proof Assistant, a formal proof management system [13]. We encode three type systems using Coq; Featherweight Immutable Java, Featherweight Generic Java and Featherweight Ownership Generic Java, and prove them sound. We describe the challenges presented in encoding immutability, ownership and type systems in general in Coq.</p>

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