A few days ago, someone asked on the Ada Drivers Library repository how to add support for the SAMD21 micro-controller. Nowadays, I would rather recommend people to contribute this kind of micro-controller support project to the Alire ecosystem. I started to write a few instructions on how to get started, but it quickly became a blog-worthy piece of text.
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.
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.
When I do Object Oriented Programming with Ada, I tend to follow a design pattern that makes it easier for me and hopefully also for people reading my code.
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.
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”.
We're happy to announce our new programming competition, the Ada/SPARK Crate Of The Year Award! We believe the Alire package manager is a game changer for Ada/SPARK, so we want to use this competition to reward the people contributing to the ecosystem.
This post continues our adventures with SPARKNaCl - our verified SPARK version of the TweetNaCl cryptographic library. This time, we'll be looking at yet more performance improvement via proof-driven "operator narrowing", porting the library to GNAT Community 2021, and the effect that has on proof and performance of the code.
Women make up roughly 38% of the global workforce, yet they constitute only 10–20% of the engineering workforce. In the U.S., numbers suggest that 40% of women who graduate with engineering degrees never enter the profession or eventually leave it. Why? The reasons vary but primarily involve socio-economic constraints on women in general, workplace inequities, and lack of support for work-life balance. Sadly, history itself has often failed to properly acknowledge the instrumental contributions of women inventors, scientists, and mathematicians who have helped solve some of our world's toughest challenges. How can young women emulate their successes if they don't even know about them?
As we've seen previously in Ada 2022 support in GNAT, the support for Ada 2022 is now mostly there for everyone to take advantage of. We're now crossing fingers for this new revision to be officially stamped by ISO in 2022.
We are happy to announce that the GNAT Community 2021 release is now available via https://www.adacore.com/download. Here are some release highlights:
The Ada 2022 draft defines a new tasking profile named Jorvik (pronounced “Yourvick”), based directly on the standard Ravenscar profile. Jorvik relaxes certain restrictions in order to increase expressive power for real-time/embedded Ada and SPARK applications. We will explore the details in this blog entry.
I am following the evolution of the embedded Rust community and in particular the work of James Munns from Ferrous-Systems. One of the projects that caught my attention is bbqueue, a single producer, single consumer, lockless, thread safe queue, based on BipBuffers.
Ada has a concurrency construct known as “entry families” that, in some cases, is just what we need to express a concise, clear solution.
In the integrated development environment, GNAT Studio, there is now a plugin that inserts the generated Global contracts inline with the code.
Following my last blog entry, further experiments show how the performance of SPARKNaCl can be doubled (again), plus analysis of worst-case stack usage and code size at all optimization levels.
This blog goes into the details of both measuring and improving the runtime performance of SPARKNaCl on a real "bare metal" embedded target, and comparing results with those for the original "TweetNaCl" C implementation.
Like previous years, AdaCore will participate in FOSDEM. This time the event will be online only, but this won’t prevent us from celebrating Open Source software. AdaCore engineers will give two talks in the Safety and Open Source devroom, a topic at the heart of AdaCore since its inception.
Beyond the great look, the Mini SAM M4 provide a powerful 120 Mhz Microchip SAMD51 Cortex-M microcontroller, a couple of LEDs and a user button. Let's program it with Ada.
Using GNAT Pro with containerization technologies, such as Docker, is so easy, a whale could do it!
In this blog post I want to present a new tool that allows one to very quickly and easily start Ada programming on any ARM Cortex-M or RISC-V microcontroller.
Some of you may recall an AdaCore blog post written in 2017 by Thales engineer Lionel Matias titled "Leveraging Ada Run-Time Checks with Fuzz Testing in AFL". This insightful post took us on a journey of discovery as Lionel demonstrated how Ada programs, compiled using GNAT Pro and an adapted assembler pass can be subjected to advanced fuzz testing. In order to achieve this Lionel demonstrated how instrumentation of the generated assembly code around jump and label instructions, could be subjected to grey-box (path aware) fuzz testing (using the original AFL v2.52b as the fuzz engine). Lionel explained how applying the comprehensive spectrum of Ada runtime checks, in conjunction with Ada's strong typing and contract based programming, enhanced the capabilities of fuzz testing beyond the abilities of other languages. Ada's advanced runtime checking, for exceptions like overflows, and the scrutiny of Ada's design by contract assertions allow corner case bugs to be found whilst also utilising fuzz testing to verify functional correctness.
Charles Villard, Cyril Etourneau, Thomas Delecroix, Louise Flick worked together in the ADArrose project. It won the student prize in the Make with Ada 2019/20 competition. This project was originally posted on Hackster.io here. For those interested in participating in the 2020/21 competition, registration is now open and project submissions will be accepted until Jan 31st 2021, register here.
The AFT (Autonomous FireTruck) is a prototype of an autonomous firetruck that can put out fire without risking people's lives. This project won a finalist prize in the Make with Ada 2019/20 competition.
Guillermo Perez's project won a finalist prize in the Make with Ada 2019/20 competition. This project was originally posted on Hackster.io here. For those interested in participating in the 2020/21 competition, registration is now open and project submissions will be accepted until Jan 31st 2021, register here.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
A few years ago we realized that having a package manager for the Ada/SPARK community would be a game changer. Since then, AdaCore has been sponsoring and contributing to the Alire project created by Alejandro Mosteo from the Centro Universitario de la Defensa de Zaragoza. With this blog post I want to introduce Alire and explain why this project is important for the `Ada`/`SPARK` community.
News from the Ada front The next revision of the Ada standard is now almost ready, so it's time for a status update on where GNAT and AdaCore stand on this front!
Blaine Osepchuk's project won a finalist prize in the Make with Ada 2019/20 competition. This project was originally posted on Hackster.io here. For those interested in participating in the 2020/21 competition, registration is now open and project submissions will be accepted until Jan 31st 2021, register here.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
Laurent Zhu's and Damien Grisonnet's project was accomplished for the EPITA Ada courses and won a finalist prize in the Make with Ada 2019/20 competition.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
Starting today, AdaCore has put in place a Code of Conduct (CoC) to ensure a positive environment for everyone willing and wanting to interact with us. With the development of this blog, our twitter accounts, and our GitHub corporate account, there is more and more communication between AdaCore and a number of communities. In this Code of Conduct we want to explain how we are going to moderate the AdaCore-maintained community spaces with the goal of maintaining a welcoming, friendly environment.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
A code obfuscator is a method of sharing coding discussions of real-world examples without giving away proprietary or classified information. This article shows an example of an Ada obfuscator, written in the SPARK language and using the Libadalang library to intelligently hide names and text within the source.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
Welcome to the Ada for micro:bit series where we look at simple examples to learn how to program the BBC micro:bit with Ada.
This is the second post of a series about GNATcoverage and source code instrumentation. The previous post introduced how GNATcoverage worked originally and why we extended it to support source instrumentation-based code coverage computation. Let’s now see it in action in the most simple case: a basic program running on the host machine, i.e. the Linux/Windows machine that runs GNATcoverage itself.
This is the first post of a series about GNATcoverage and source code instrumentation.In order to make GNATcoverage viable in more contexts, we planned several years ago to add instrumentation support in GNATcoverage for Ada sources. This feature reached maturation recently and is available in the last Continuous Release, so it is a good time to present it with a blog series!
The FACE™ approach is a government-industry initiative for reducing defense system life cycle costs through portable and reusable software components. It consists of a technical approach — a software standard based on well-defined common interfaces — and a business strategy for encouraging the development and deployment of FACE conformant products.
Hedley Rainnie's project combines 6 different SoCs all programmed in Ada performing as a LoRa network. He also showcases a BLE bridge to a LoRa server. His project came about when him and his wife were musing about how to detect and deter unwanted garden visitors. This ongoing project won a finalist prize in the 2019/20 Make with Ada competition.
SPARK always being under development, new language features make it in every release of the tool, be they previously unsupported Ada features (like access types) or SPARK specific developments. However, new features generally take a while to make it into actual user code. The feature I am going to present here is in my experience an exception, as it was used both internally and by external users before it made it into any actual release. It was designed to enhance the verification of data initialization, whose limitations have been a long standing issue in SPARK.
Shahariar's project ensures safety against electrical fire or shock during an earthquake, flood, gas leakage or fire breakout by disconnecting the mains with a smart circuit breaker. Additionally, this project won a finalist prize in the 2019/20 Make with Ada competition.
Team CryptAda's project collects entropy, manages an entropy pool, implements a homemade PRNG, and generates RSA keys directly on the board with an accent on security. Additionally, this project won a finalist prize in the 2019/20 Make with Ada competition.
John Singleton's The SmartBase makes your existing adjustable bed safer and easier to use by adding voice control and safe (and fun!) LED underbed lighting! Additionally, this project won first place prize in the 2019/20 Make with Ada competition.
Last year, I started evaluating programming languages for a formally-verified operating system. I've been developing software for a while, but only recently began work in high integrity software development and formal methods. There are several operating system projects, like the SeL4 microkernel and the Muen separation kernel, that make use of formal verification. But I was interested in using a formally-verified language to write a general-purpose OS - an environment for abstracting the underlying hardware while acting as an arbiter for running the normal applications we're used to.
We are happy to announce that the GNAT Community 2020 release is now available! Read the post for access to download and to find out about this year's release highlights.
This blog entry describes the transformation of an Ada stack ADT into a completely proven SPARK implementation that relies on static verification instead of run-time enforcement of the abstraction’s semantics. We will prove that there are no reads of unassigned variables, no array indexing errors, no range errors, no numeric overflow errors, no attempts to push onto a full stack, no attempts to pop from an empty stack, that subprogram bodies implement their functional requirements, and so on. As a result, we get a maximally robust implementation of a reusable stack abstraction providing all the facilities required for production use.