AdaCore Blog

67 entries tagged with #Runtime

by Fabien Chouteau

Embedded Ada/SPARK, There's a Shortcut

For years in this blog my colleagues and I have published examples, demos, and how-to’s on Ada/SPARK embedded (as in bare-metal) development. Most of the time, if not always, we focused on one way of doing things: to start from scratch and write everything in Ada/SPARK, from the low level drivers to the application. While this way of doing Ada/SPARK embedded will yield the best results in terms of software quality, it might not be the most efficient in all cases. In this blog post I want to present an alternative method to introduce Ada/SPARK into your embedded development projects.

#Embedded   

by Yannick Moy , Claire Dross

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   

by Paul Butcher

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   

by Yannick Moy

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   

by Pat Rogers

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   

by Yannick Moy

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   

by Kyriakos Georgiou

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   

by Roderick Chapman

SPARKNaCl with GNAT and SPARK Community 2021: Port, Proof and Performance

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.

#SPARK     #Cryptography    #Formal Verification    #Code generation    #RISC-V    #Security   

by Paul Butcher

Finding Vulnerabilities using Advanced Fuzz testing and AFLplusplus v3.0

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.

#Security   

by Jon Andrew

CuBit: A General-Purpose Operating System in SPARK/Ada

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.

by Pat Rogers

Making an RC Car with Ada and SPARK

As a demonstration for the use of Ada and SPARK in very small embedded targets, I created a remote-controlled (RC) car using Lego NXT Mindstorms motors and sensors but without using the Lego computer or Lego software. I used an ARM Cortex System-on-Chip board for the computer, and all the code -- the control program, the device drivers, everything -- is written in Ada. Over time, I’ve upgraded some of the code to be in SPARK. This blog post describes the hardware, the software, the SPARK upgrades, and the repositories that are used and created for this purpose.

#Ada    #SPARK    #Robotics   

by Boran Car

Bringing Ada To MultiZone

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.

#Ada    #Embedded    #Embedded Development    #Security    #multizone    #Hex-Five   

by Allan Ascanius , Per Dalgas Jakobsen

Winning DTU RoboCup with Ada and SPARK

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.

#Robotics    #Ada    #SPARK   

by Joffrey Huguet

Using SPARK to prove 255-bit Integer Arithmetic from Curve25519

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.

#SPARK    #Formal Verification    #Cryptography   

by Peter Chapin

Ten Years of Using SPARK to Build CubeSat Nano Satellites With Students

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.

#SPARK    #Space    #Education    #Safety   

by Yannick Moy

Security Agency Uses SPARK for Secure USB Key

​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.

#SPARK    #Security    #Formal Methods   

by Lionel Matias

Leveraging Ada Run-Time Checks with Fuzz Testing in AFL

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.

#Testing    #Ada    #VerificationTools   

by J. German Rivera

Make with Ada 2017- A "Swiss Army Knife" Watch

SummaryThe Hexiwear is an IoT wearable development board that has two NXP Kinetis microcontrollers. One is a K64F (Cortex-M4 core) for running the main embedded application software. The other one is a KW40 (Cortex M0+ core) for running a wireless connectivity stack (e.g., Bluetooth BLE or Thread). The Hexiwear board also has a rich set of peripherals, including OLED display, accelerometer, magnetometer, gryroscope, pressure sensor, temperature sensor and heart-rate sensor. This blog article describes the development of a "Swiss Army Knife" watch on the Hexiwear platform. It is a bare-metal embedded application developed 100% in Ada 2012, from the lowest level device drivers all the way up to the application-specific code, for the Hexiwear's K64F microcontroller. I developed Ada drivers for Hexiwear-specific peripherals from scratch, as they were not supported by AdaCore's Ada drivers library. Also, since I wanted to use the GNAT GPL 2017 Ada compiler but the GNAT GPL distribution did not include a port of the Ada Runtime for the Hexiwear board, I also had to port the GNAT GPL 2017 Ada runtime to the Hexiwear. All this application-independent code can be leveraged by anyone interested in developing Ada applications for the Hexiwear wearable device.

by Jonas Attertun

Make with Ada 2017: Brushless DC Motor Controller

This project involves the design of a software platform that provides a good basis when developing motor controllers for brushless DC motors (BLDC/PMSM). It consist of a basic but clean and readable implementation of a sensored field oriented control algorithm. Included is a logging feature that will simplify development and allows users to visualize what is happening. The project shows that Ada successfully can be used for a bare-metal project that requires fast execution.

#Makers    #MakewithAda    #STM32    #Embedded   

by Yannick Moy

Research Corner - Focused Certification of SPARK in Coq

The SPARK toolset aims at giving guarantees to its users about the properties of the software analyzed, be it absence of runtime errors or more complex properties. But the SPARK toolset being itself a complex tool, it is not free of errors. To get confidence in its results, we have worked with academic partners to establish mathematical evidence of the correctness of a critical part of the SPARK toolset. The part on which we focused is the tagging of nodes requiring run-time checks by the frontend of the SPARK technology. This work has been accepted at SEFM 2017 conference.

#SPARK   

by Yannick Moy

VerifyThis Challenge in SPARK

This year again, the VerifyThis competition took place as part of ETAPS conferences. This is the occasion for builders and users of formal program verification platforms to use their favorite tools on common challenges. The first challenge this year was a good fit for SPARK, as it revolves around proving properties of an imperative sorting procedure. In this post, I am using this challenge to show how one can reach different levels of software assurance with SPARK.

#Formal Verification    #SPARK   

by Jorge Real

Writing on Air

While searching for motivating projects for students of the Real-Time Systems course here at Universitat Politècnica de València, we found a curious device that produces a fascinating effect. It holds a 12 cm bar from its bottom and makes it swing, like an upside-down pendulum, at a frequency of nearly 9 Hz. The free end of the bar holds a row of eight LEDs. With careful and timely switching of those LEDs, and due to visual persistence, it creates the illusion of text... floating in the air!

#STM32    #Ravenscar    #Ada    #Makers    #Embedded Development   

by Fabien Chouteau , Arnaud Charlet , Yannick Moy

SPARK Tetris on the Arduboy

One of us got hooked on the promise of a credit-card-size programmable pocket game under the name of Arduboy and participated in its kickstarter in 2015. The kickstarter was successful (but late) and delivered  the expected working board in mid 2016. Of course, the idea from the start was to program it in Ada , but this is an 8-bits AVR microcontroller (the ATmega32u4 by Atmel) not supported anymore by GNAT Pro. One solution would have been to rebuild our own GNAT compiler for 8-bit AVR from the GNAT FSF repository and use the AVR-Ada project. Another solution, which we explore in this blog post, is to use the SPARK-to-C compiler that we developed at AdaCore to turn our Ada code into C and then use the Arduino toolchain to compile for the Arduboy board.

by Yannick Moy

GNATprove Tips and Tricks: What’s Provable for Real?

SPARK supports two ways of encoding reals in a program: the usual floating-point reals, following the standard IEEE 754, and the lesser known fixed-point reals, called this way because their precision is fixed (contrary to floating-points whose precision varies with the magnitude of the encoded number). This support is limited in some ways when it comes to proving properties of computations on real numbers, and these limitations depend strongly in the encoding chosen. In this post, I show the results of applying GNATprove on simple programs using either floating-point or fixed-point reals, to explain these differences.

#Formal Verification    #SPARK   

by Anthony Leonardo Gracio

How to prevent drone crashes using SPARK

The Crazyflie is a very small quadcopter sold as an open source development platform: both electronic schematics and source code are directly available on their GitHub and its architecture is very flexible. Even if the Crazyflie flies out of the box, it has not been developed with safety in mind: in case of crash, its size, its weight and its plastic propellers won’t hurt anyone! But what if the propellers were made of carbon fiber, and shaped like razor blades to increase the drone’s performance? In theses circumstances, a bug in the flight control system could lead to dramatic events. In this post, I present the work I did to rewrite the stabilization system of the Crazyflie in SPARK 2014, and to prove that it is free of runtime errors. SPARK also helped me to discover little bugs in the original firmware, one of which directly related with overflows. Besides the Crazyflie, this work could be an inspiration for others to do the same work on larger and more safety-critical drones.

#UAVs    #crazyflie    #SPARK    #Drones   

by Martyn Pike

The latest Mixed Programming with Ada lectures at the AdaCore University

I recently joined AdaCore as a Technical Account Manager with an initial focus on the UK and Scandinavian regions, but for the last 12 months I've been busy working on the AdaCore University. The most recent addition to which is a course on Mixed Language Programming with Ada, and it includes lectures on the integration of Ada with C, C++ and Java. The course covers some advanced topics like mixed language object orientation, techniques for using Ada strong typing to combat known issue with C pointers and the pitfalls that are encountered when mixing native Ada code with Java at runtime. This course clearly demonstrates that Ada has strong support for integration with C, C++ and Java and it proves there are no technical barriers to its adoption in modern mixed language software systems.

#Mixed Language    #AdaCore University    #Java    #C++    #C    

by Olivier Ramonat

AdaCore Releases GNAT Pro 7.3, QGen 1.0 and GNATdashboard 1.0

February saw the annual customer release of a number of important products. This is no mean task when you consider the fact that GNAT Pro is available on over 50 platforms and supports over 150 runtime profiles (ranging from Full Ada Support to the very restricted Zero Footprint Profile suitable for safety-critical development). All in all, from the branching of the preview version to the customer release it takes us nearly 4 months to package everything up! Quality is assured through the internally developed AdaCore Factory.

#GNAT Pro    #SPARK Pro    #GPS    #GNATbench    #GNATdashboard    #Ada    #AdaCore Factory    #CodePeer    #QGen   

by Tristan Gingold

AdaCore at FOSDEM'15

I was at Bruxelles on January 31st to present the components of GNAT GPL 2015 : SPARK 2014 and GNAT GPL for ARM bare-board. This is not unrelated to a previous blog entry on Tetris in SPARK on ARM Cortex M4, in particular I presented that Tetris demo (I brought some boards with me and despite the simple package, none were broken!). The slides contain technical details on the ravenscar profile (main principles), how to build a program for the stm32f4-discovery board and how to port the runtime. There are also less technical slides such as why we choose the stm32f4 board and photos of some graphical demos. As that could be useful to anyone interested in Ravenscar or in porting the runtime to other boards or other platforms, we've made the slides available here.

#ARM    #Ravenscar    #FOSDEM    #GNATGPL