Part of our core expertise at AdaCore is to integrate multiple technologies as smoothly as possible and make it a product. This started at the very beginning of our company by integrating a code generator (GCC) with an Ada front-end (GNAT) which was then followed by integrating a debugger engine (GDB) and led to today's rich GNAT Pro offering.
How I learned to write SPARK-provable code using Conway's Game Of Life
As seen in a previous post, it is possible to use pointers (or access types) in SPARK provided the program abides by a strict memory ownership policy designed to prevent aliasing. We will show in this post how to define pointer-based data-structures in SPARK and how to traverse them without breaking the ownership policy.
Presenting the GNAT LLVM project At AdaCore labs, we have been working for some time now on combining the GNAT Ada front-end with a different code generator than GCC.
AdaCore’s fourth annual Make with Ada competition launched this week with over $8K in cash and prizes to be awarded for the most innovative embedded systems projects developed using Ada and/or SPARK.
The Ada Community has gathered recently around a new exciting initiative - an Ada Virtual Conference, to present Ada-related topics in a 100% remote event. The first such conference took place on August, 10th 2019, around the topic of the new features in Ada 202x. Here is what was presented.
The challenge faced by cryptography APIs is to make building functional and secure programs easy for the user. In this blog post I will present you how I created a SPARK binding for Libsodium, using strong typing and preconditions/postconditions to enforce a safe and functional use of basic cryptographic primitives.
The functionality of many security-critical programs is directly related to Input/Output (I/O). This includes command-line utilities such as gzip, which might process untrusted data downloaded from the internet, but also any servers that are directly connected to the internet, such as webservers, DNS servers and so on. In this blog post we show an approach that deals with error handling and reasoning about content, and demonstrate the approach using the cat command line utility.
I am an Associate Professor at Polytechnic University of Madrid’s (Universidad Politécnica de Madrid / UPM) in the Department of Architecture and Technology of Computer Systems. For the past several years I have been directing a team of colleagues and students in the development of a UPMSat-2 microsatellite. The project originally started in 2013 as a follow-to the UPM-SAT 1, launched by an Ariane-4 in 1995.
Interested in participating in the evolution of the Ada or SPARK languages? We have something for you.
In this blog post, I will present one of the most interesting additions to the community 2019 version of SPARK: pointer support. One of the core assumption in SPARK has always been the absence of aliasing, so adding pointers without breaking this assumption was quite a challenge. I will explain how this was achieved using an ownership model for pointers (like is done in Rust) through small examples.
We are pleased to announce that GNAT Community 2019 has been released! See https://www.adacore.com/download.
C is the dominant language of the embedded world, almost to the point of exclusivity. Due to its age, and its goal of being a “portable assembler”, it deliberately lacks type-safety, opening up exploit vectors. Proposed solutions are partitioning the application into smaller intercommunicating blocks, designed with the principle of least privilege in mind; and rewriting the application in a type-safe language. We believe that both approaches are complementary and want to show you how to combine separation and isolation provided by MultiZone together with iteratively rewriting parts in Ada. We will take the MultiZone SDK demo and rewrite one of the zones in Ada.
The Danish Technical University has a yearly RoboCup where autonomous vehicles solve a number of challenges. We participated with RoadRunner, a 3D printed robot with wheel suspension, based on the BeagleBone Blue ARM-based board and the Pixy 1 camera with custom firmware enabling real-time line detection. Code is written in Ada and formally proved correct with SPARK at Silver level.
In 2014, Adam Langley, a well-known cryptographer from Google, wrote a post on his personal blog, in which he tried to prove functions from curve25519-donna, one of his projects, using various verification tools: SPARK, Frama-C, Isabelle... He describes this attempt as "disappointing", because he could not manage to prove "simple" things, like absence of runtime errors. I will show in this blogpost that today, it is possible to prove what he wanted to prove, and even more.
This course is geared to software professionals looking for a practical introduction to the Ada language with a focus on embedded systems, including real-time features as well as critical features introduced in Ada 2012. By attending this course you will understand and know how to use Ada for both sequential and concurrent applications, through a combination of live lectures from AdaCore's expert instructors and hands-on workshops using AdaCore's latest GNAT technology. AdaCore will provide an Ada 2012 tool-chain and ARM-based target boards for embedded workshops. No previous experience with Ada is required.
A question that our users sometimes ask us is "do you use CodePeer at AdaCore and if so, how?". The answer is yes! and this blog post will hopefully give you some insights into how we are doing it for our own needs.
My colleague, Carl Brandon, and I have been running the CubeSat Laboratory at Vermont Technical College (VTC) for over ten years. During that time we have worked with nearly two dozen students on building and programming CubeSat nano satellites. Because of their general inexperience, and because of the high student turnover rate that is natural in an educational setting, our development process is often far from ideal. Here SPARK has been extremely valuable to us. What we lack in rigor of the development process we make up for in the rigor of the SPARK language and tools. In November 2013 we launched a low Earth orbiting CubeSat. The launch vehicle contained 13 other university built CubeSats. Most were never heard from. One worked for a few months. Ours worked for two years until it reentered Earth's atmosphere as planned in November 2015.
MISRA C is the most widely known coding standard restricting the use of the C programming language for critical software. For good reasons. For one, its focus is entirely on avoiding error-prone programming features of the C programming language rather than on enforcing a particular programming style. In addition, a large majority of rules it defines are checkable automatically (116 rules out of the total 159 guidelines), and many tools are available to enforce those. As a coding standard, MISRA C even goes out of its way to define a consistent sub-language of C, with its own typing rules (called the "essential type model" in MISRA C) to make up for the lack of strong typing in C.
Like last year, we've sent a squad of AdaCore engineers to participate in the celebration of Open Source software at FOSDEM. Like last year, we had great interactions with the rest of the Ada and SPARK Community in the Ada devroom on Saturday. That's what we have to say about it.
In Part 1 of this blog post I discussed why I chose to implement this application using the Ada Web Server to serve the computed fractal to a web browser. In this part I will discuss a bit more about the backend of the application, the Ada part.
The is the first part of a multiple part post that covers the development of the AdaFractal project. The idea was to create fractals in Ada. Here we will cover how to use AWS to create a flexible and portable way to display the generated fractals without using bulky graphics libraries.
Over the past several years, a great number of public announcements have been made about companies that are either studying or adopting the Ada and SPARK programming languages. Noteworthy examples include Dolby, Denso, LASP and Real Heart, as well as the French Security Agency.
The promise behind the SPARK language is the ability to formally demonstrate properties in your code regardless of the input values that are supplied - as long as those values satisfy specified constraints. As such, this is quite different from static analysis tools such as our CodePeer or the typical offering available for e.g. the C language, which trade completeness for efficiency in the name of pragmatism. Indeed, the problem they’re trying to solve - finding bugs in existing applications - makes it impossible to be complete. Or, if completeness is achieved, then it is at the cost of massive amount of uncertainties (“false alarms”). SPARK takes a different approach. It requires the programmer to stay within the boundaries of a (relatively large) Ada language subset and to annotate the source code with additional information - at the benefit of being able to be complete (or sound) in the verification of certain properties, and without inundating the programmer with false alarms.
Byron Cook, who founded and leads the Automated Reasoning Group at Amazon Web Services (AWS) Security, gave a powerful talk at the Federated Logic Conference in July about how Amazon uses formal methods for ensuring the security of parts of AWS infrastructure. In the past four years, this group of 20+ has progressively hired well-known formal methods experts to face the growing demand inside AWS to develop tools based on formal verification for reasoning about cloud security. What is unique so far is the level of investment at AWS in formal verification as a means to radically eliminate some security problems, both for them and for their customers. This is certainly an approach we're eager to support with our own investment in the SPARK technology.
The challenge Are you ready to develop a project to the highest levels of safety, security and reliability? If so, Make with Ada is the challenge for you! We’re calling on embedded developers across the globe to build cool embedded applications using the Ada and SPARK programming languages and are offering over $8000 in total prizes. In addition, eligible students will compete for a reward of an Analog Discovery 2 Pro Bundle worth $299.99!
This course is geared to software professionals looking for a practical introduction to the Ada language with a focus on embedded systems, including real-time features as well as critical features introduced in Ada 2012. By attending this course you will understand and know how to use Ada for both sequential and concurrent applications, through a combination of live lectures from AdaCore's expert instructors and hands-on workshops using AdaCore's latest GNAT technology. AdaCore will provide an Ada 2012 tool-chain and ARM-based target boards for embedded workshops. No previous experience with Ada is required.
I was looking for a topic for my master thesis in embedded systems engineering when one of my advisor proposed the idea of programming a control system for autonomous trains in Ada. Since I am fascinated by the idea of autonomous vehicles I agreed immediately without knowing Ada.
When I bought the TinyFPGA-BX board, I thought it would be an opportunity to play a little bit with FPGA, learn some Verilog or VHDL. But when I discovered that it was possible to have a RISC-V CPU on it, I knew I had to run Ada code on it.
We are happy to announce that, AdaCore, alongside Altran and Jaguar Land Rover will be major sponsors of the fifth edition of the renowned High Integrity Software Conference on the 6th November in Bristol!
We are very proud to announce the availability of our new Ada and SPARK learning platform learn.adacore.com, which will replace AdaCoreU(niversity) e-learning platform. Learn all about it in this blog post.
Calling all members of the Ada and SPARK community, we are pleased to announce that GNAT Community 2018 is here! adacore.com/download
ANSSI, the French national security agency, has published the results of their work since 2014 on designing and implementing an open-hardware & open-source USB key that provides defense-in-depth against vulnerabilities on the USB hardware, architecture, protocol and software stack. In this project called WooKey, Ada and SPARK are key components for the security of the platform. This is a very compelling demontration of both the usability and the power of safe languages and formal verification to develop secure systems.
There is a long-standing debate about which phase in the Software Development Life Cycle causes the most bugs: is it the specification phase or the coding phase? A recent study by NIST shows that, in the software industry at large, coding bugs are causing the majority of security issues. Choosing a safer language like Ada or SPARK is a critical component for reducing these vulnerabilities that result from simple mistakes. In a new freely available booklet, we explain how these languages and the associated toolsets can be used to increase the security of software.
Last week, the programmer Hillel posted a challenge (the link points to a partial postmortem of the provided solutions) on Twitter for someone to prove a correct implementation of three small programming problems: Leftpad, Unique, and Fulcrum.
PolyORB, AdaCore's versatile distribution middleware, now lives on Github. Its new home is https://github.com/AdaCore/polyorb
This is part #2 of the SPARKZumo series of blog posts. This post covers the build system that was used to build the SPARKZumo project and how to automate the process in GPS.
One of the most criticized aspect of the Ada language throughout the years has been its outdated syntax. Fortunately, AdaCore decided to tackle this issue by implementing a new, modern, syntax for Ada.
There are a lot of DIY CNC projects out there (router, laser, 3D printer, egg drawing, etc.), but I never saw a DIY CNC sandblaster. So I decided to make my own.
So you want to use SPARK for your next microcontroller project? Great choice! All you need is an Ada 2012 ready compiler and the SPARK tools. But what happens when an Ada 2012 compiler isn’t available for your architecture?
AdaCore has been working with CEA, Inria and NIST to organize a two-days event dedicated to sound static analysis techniques and tools, and how they are used to increase the security of software-based systems. The program gathers top-notch experts in the field, from industry, government agencies and research institutes, around the three themes of analysis of legacy code, use in new developments and accountable software quality. Here is why it is worth attending.
SPARK user Alexander Senier presented recently at BOB Konferenz in Germany their use of SPARK for building secure mobile architectures. What's nice is that they build on the guarantees that SPARK provides at software level to create a secure software architecture based on the Genode operating system framework. They present 3 interesting architectural designs that make it possible to build a trustworthy system out of untrustworthy building blocks. Almost as exciting as Alchemy's goal of transforming lead into gold! Here is the video of that presentation.
Updated July 2018
Tokeneer is a software for controlling physical access to a secure enclave by means of a fingerprint sensor. This software was created by Altran (Praxis at the time) in 2003 using the previous generation of SPARK language and tools, as part of a project commissioned by the NSA to investigate the rigorous development of critical software using formal methods. The project artefacts, including the source code, were released as open source in 2008. Tokeneer was widely recognized as a milestone in industrial formal verification. We recently transitioned this software to SPARK 2014, and it allowed us to go beyond what was possible with the previous SPARK technology. We have also shown how security vulnerabilities introduced in the code can be detected by formal verification.
This blog post is part two of a tutorial based on the OpenGLAda project and will cover implementation details such as a type system for interfacing with C, error handling, memory management, and loading functions.
With the recent addition of a Manual Proof capability in SPARK 18, it is worth looking at an example which cannot be proved by automatic provers, to see the options that are available for proving it with SPARK. We present three ways to complete a proof beyond what automatic provers can do: using an alternative automatic prover, proving interactively inside our GPS IDE, and using an alternative interactive prover.
Bitcoin is getting a lot of press recently, but let's be honest, that's mostly because a single bitcoin worth 800 USD in January 2017 was worth almost 20,000 USD in December 2017. However, bitcoin and its underlying blockchain are beautiful technologies that are worth a closer look. Let’s take that look with our Ada hat on!
This blog post is part one of a tutorial based on the OpenGLAda project and will cover some the background of the OpenGL API and the basic steps involved in importing platform-dependent C functions.
Every year, free and open source enthusiasts gather at Brussels (Belgium) for two days of FLOSS-related conferences. FOSDEM organizers setup several “developer rooms”, which are venues that host talks on specific topics. This year, the event will happen on the 3rd and 4th of February (Saturday and Sunday) and there is a room dedicated to the Ada programming language.
Fuzzing is a very popular bug finding method. The concept, very simple, is to continuously inject random (garbage) data as input of a software component, and wait for it to crash. If, like me, you find writing robustness test tedious and not very efficient in finding bugs, you might want to try fuzzing your Ada code. Here's a recipe to fuzz-test your Ada code, using American Fuzzy Lop and all the runtime checks your favorite Ada compiler can provide. Let's see (quickly) how AFL works, then jump right into fuzzing 3 open-source Ada libraries: ZipAda, AdaYaml, and GNATCOLL.JSON.