Ada Crate of the Year: Interactive code search

A retrospective on learning Ada and developing a tool with it in 2021 from 2021 Ada Crate of the Year Winner Paul Jarrett.

#Ada    #Alire    #Crate   

Handling Aliasing through Pointers in SPARK

As I explained in a blog post a couple of years ago, pointers are subjected to a strict ownership policy in SPARK. It prevents aliasing and allows for an efficient formal verification model. Of course, it comes at the cost of restrictions which might not be applicable to all usage. In particular, while ownership makes it possible to represent certain recursive data-structures, those involving cycles or sharing are de-facto forbidden. This is a choice, and not every proof tool did the same. For example, the WP plug-in of Frama-C supports pointers with arbitrary aliasing. If some information about the separation of memory cells is necessary to verify a program, then the user shall give the annotation explicitly. I have investigated modeling pointers with aliasing in SPARK as indices in a big memory array. I will present the results of my experiments in this blog post. We will see that, while such a representation is indeed possible modulo some hiding in SPARK, it can quickly become rather heavy in practice.

#SPARK    #Data Structures    #Formal Verification   

Ada GameDev Part 2: Making 2D maps with Tiled

In this second post of the Ada GameDev series we will see how to create game maps and export them to a format that is compatible with the GESTE library.

#Embedded    #GameDev   

SPARK Crate of the Year: Unbounded containers in SPARK

Manuel Hatzl is the winner of the 2021 SPARK Crate of the year! In this blog post he shares his experience using Ada/​SPARK and how he created the spark_unbound library

#SPARK    #Unbound    #Data Structures   

Ada GameDev Part 1: GEneric Sprite and Tile Engine (GESTE)

In this first entry of the series, I want to present my GEneric Sprite and Tile Engine (GESTE) project. The goal of GESTE is to bring the rendering and anesthetic of 8bit era game consoles to modern microcontrollers.

#Embedded    #GameDev   

Proving the Correctness of GNAT Light Runtime Library

The GNAT light runtime library is a version of the runtime library targeted at embedded platforms and certification, which has been certified for use at the highest levels of criticality in several industrial domains. It contains around 180 units focused mostly on I/O, numerics, text manipulation, memory operations. We have used SPARK to prove the correctness of 40 of them: that the code is free of runtime errors, and that it satisfies its functional specifications.

#SPARK    #Runtime    #Proof   

SPARKNaCl - Two Years of Optimizing Crypto Code in SPARK (and counting)

SPARKNaCl is a SPARK ver­sion of the Tweet­Na­Cl cryp­to­graph­ic library, developed by formal methods and security expert Rod Chapman. For two years now, Rod has been developing and optimizing this open-source cryptographic library while preserving the automatic type-safety proof across code changes and tool updates. He has recently given a talk about this experience that I highly recommend.

#SPARK    #Cryptography    #Formal Verification   

Fuzz Testing in International Aerospace Guidelines

Through the HICLASS UK research group, AdaCore has been developing security-focused software development tools that are aligned with the objectives stated within the avionics security standards. In addition, they have been developing further guidelines that describe how vulnerability identification and security assurance activities can be described within a Plan for Security Aspects of Certification.

#Fuzzing    #Cyber Security    #Civil Avionics    #DO-356A    #ED-203A   

Enhancing the Security of a TCP Stack with SPARK

The developers of CycloneTCP library at Oryx Embedded partnered with AdaCore to replace the TCP part of the C codebase by SPARK code, and used the SPARK tools to prove both that the code is not vulnerable to the usual runtime errors (like buffer overflow) and that it correctly implements the TCP automaton specified in RFC 793. As part of this work, we found two subtle bugs related to memory management and concurrency. This work has been accepted for publication at the upcoming IEEE SecDev 2021 conference.

#SPARK    #Security    #Formal Verification   

Task Suspension with a Timeout in Ravenscar/Jorvik

This blog entry shows how to define an abstract data type that allows tasks to block on objects of the type, waiting for resumption signals from other components, for at most a specified amount of time per object. This "timeout" capability has been available in Ada from the beginning, via select statements containing timed entry calls. But what about developers working within the Ravenscar and Jorvik tasking subsets? Select statements and timed calls are not included within either profile. This new abstraction will provide some of the functionality of timed entry calls, with an implementation consistent with the Ravenscar and Jorvik subsets.

#Ada    #Tasking    #Ravenscar    #Jorvik    #Timeouts    #Timing_Event    #Suspension_Object   

When the RISC-V ISA is the Weakest Link

NVIDIA has been using SPARK for some time now to develop safety- and security-critical firmware applications. At the recent DEF CON 29, hackers Zabrocki and Matrosov presented how they went about attacking NVIDIA firmware written in SPARK but ended up attacking the RISC-V ISA instead!Zabrocki starts by explaining the context for their red teaming exercise at NVIDIA, followed by a description of SPARK and their evaluation of the language from a security attack perspective. He shows how they used an extension of Ghidra to decompile the binary code generated by GNAT and describes the vulnerability they identified in the RISC-V ISA thanks to that decompilation. Matrosov goes on to explain how they glitched the NVIDIA chip to exploit this vulnerability. Finally, Zabrocki talks about projects used to harden RISC-V platforms.

#Security    #SPARK    #RISC-V   

Security-Hardening Software Libraries with Ada and SPARK

Part of AdaCore's ongoing efforts under the HICLASS project is to demonstrate how the SPARK technology can play an integral part in the security-hardening of existing software libraries written in other non-security-oriented programming languages such as C. This blog post presents the first white paper under this work-stream, “Security-Hardening Software Libraries with Ada and SPARK”.

#SPARK    #STM32    #Embedded