An Architecture-Agnostic Analysis Framework for Binary Executables

Total Page:16

File Type:pdf, Size:1020Kb

An Architecture-Agnostic Analysis Framework for Binary Executables MENTALESE - An Architecture-Agnostic Analysis Framework for Binary Executables Dissertation zur Erlangung des Grades eines Doktor-Ingenieurs der Fakultät für Elektrotechnik und Informationstechnik an der Ruhr-Universität Bochum vorgelegt von Behrad Garmany geboren in Maschhad Bochum, November 2020 ii Gutachter: Prof. Dr. Thorsten Holz, Ruhr-Universität Bochum Zweitgutachter: Prof. Dr. Konrad Rieck, Technische Universität Braunschweig Tag der mündlichen Prüfung: 11. Februar 2021 Acknowledgements I am deeply grateful to my advisor Prof. Dr. Thorsten Holz for his support, guidance, and patience. He has given me the chance to pursue my interests in binary analysis and reverse engineering, which have been the focus of my studies for the past years. I would also like to thank Prof. Dr. Konrad Rieck for spending his valuable time for the review of this work. During my time at the chair of systems security, I had the chance and the pleasure to work with inspiring, collaborating, and hard working people to achieve common research goals. In particular, I would like to mention Martin Stoffel, Robert Gawlik, Jannik Pewny, Moritz Contag, Philipp Koppe, Benjamin Kollenda, Andre Pawlowski, Tim Blazytko, and Sebastian Vogl. Special thanks goes to Jannik Pewny who was spending his precious time to present our paper at the 34th Annual Computer Security Applications Conference whilst I was unable to travel, even though he was not part of the group of authors. Additionally, I would like to thank Cornelius Aschermann for inspiring talks and brainstorming discussions as well as a continuous reminder to keep going. I would also like to thank all other students who I had a great time with during my years at the chair. I want to express my gratitude to my friends Carsten Willems, Johannes Dahse, and Felix Schuster for their continuous support and encouragement to not lose track. My deepest gratitude goes to my parents and my sister for their unconditional love and support over all the years, encouraging me to pursue my passion. In the past three years I had the greatest luck to spend my life with my fiancé Verena who stood by my side and supported me with all my decisions. Abstract Static program analysis enables to reason about program behavior and its semantic properties without actually running the program. It enjoys a wealth of achievements based on decades of research. Unfortunately, it comes with some unpleasant computational drawbacks that stem from the problem that almost any interesting property to reason about is undecidable. Our field of research presented in this thesis, tackles a niche in the sector of program analysis which comes with the aspect of binary programs. At the end of each translation pipeline, it is the binary that is executed. Apparently, binary program analysis is the only choice when source code is not available. While it poses additional challenges that increase the complexity giving rise to more undecidable problems to deal with, it also has some pleasant properties which aid in the process of the analysis. Syntactic edge cases and language features, for instance are in a sense canonicalized, and many modules of a program are compiled into a single binary. The Internet of Things era has given rise to a high competition among companies that induced the use of commercial third party software that are usually shipped as binaries. A popular trend in third party code reuse incorporates more and more open source software which comes at risk. This era poses an additional interest in architecture agnostic tools that aid in the process of cross architecture binary analysis. Similarly to the interest for source code analyzers that concentrate on covering many languages, our interest concentrates on covering many architectures. This brings us to the first problem to be tackled—aside from the disassembly and control flow recovery— which comes with the choice of a proper intermediate language (IL). Ideally, the IL covers many architectures, has a small semantic footprint (small instruction set), and allows developing generic analyses that can be applied to all architectures. This thesis introduces Mentalese (language of thought), a framework for architecture agnostic analysis. The name is inspired by the philosophical hypothesis that assumes a language in which processes of thought take place. The way we approached binary analysis resembles in many ways this process. We discuss in this work our early steps to find a suitable IL and specify the design and the choices we made to build a framework that adds value to our field of binary analysis. The design of Mentalese, is concentrated to be scalable, flexible, accessible, and extensible. Based on our prototype we have developed tools that aided in the process of exploitation, cross architecture bug search, and bug detection. Zusammenfassung Die statische Code-Analyse ermöglicht das Ableiten von Aussagen über das Program- mverhalten und seine semantischen Eigenschaften ohne die tatsächliche Ausführung des Programms. Das Feld genießt einen Reichtum von Errungenschaften, die auf jahrzehntelanger Forschung beruhen. Leider ist mit der statischen Analyse das klassische Problem der Unentscheidbarkeit verknüpft, da fast jede interessante Eigenschaft nach der wir fragen eine nicht triviale und semantische Eigenschaft ist. Die Gesetzte der Berechenbarkeit erlauben kein Programm das für alle Programme eine solche Eigenschaft nachweisen kann. Die in dieser Dissertation vorgestellte Forschung nimmt eine Nische im Bereich der statischen Programmanalyse ein, dessen Anwendung sich auf binäre (aus- führbare) Programme fokussiert. Am Ende der Übersetzungspipeline des Quellcodes, ist es die Binärdatei, die auf der jeweiligen Maschine zu Ausführung kommt. Ist der Quellcode nicht verfügbar, so bleibt die binäre Analyse die einzige Wahl. Hierdurch wird die Analyse vor zusätzliche Herausforderungen gestellt, die wir in dieser Arbeit diskutieren. Allerdings hat die Analyse auf binärer Ebene auch Vorteile vorzuweisen. So werden syntaktische Strukturen und Sprachfeatures auf Maschinenebene kanonisiert. Auch werden viele Quellcode Module in eine einzige ausführbare Datei übersetzt, so dass das Programm im Gesamtkontext analysiert werden kann. Die Ära des Internets der Dinge (IOT) hat zu einer erhöhten Konkurrenz zwischen Unternehmen geführt, die vermehrt den Einsatz von kommerzieller Software von Drittanbietern induziert. Diese werden üblicherweise als ausführbare Binärdateien ausgeliefert. Ein beliebter Trend bei der Wiederverwendung von Drittanbietercode umfasst immer mehr die Einbindung von Open-Source-Software, die nicht ohne Risiko ist. Die Konsequenz ist ein Bedarf an architekturunabhängigen Tools, die den Prozess der architekturübergreifenden Binäranalyse ermöglicht. Dabei verfolgen wir, analog zum Trend kommerzieller Quellcodeanalysen, die ein möglichst breites Spektrum an Programmiersprachen abdecken, das Interesse möglichst viele Architeckturen abzudecken. Dies führt uns zu unserem ersten Problem, das neben dem Prozess des Disassemblierens und der Wiederherstellung des Kontrollflusses, die Wahl einer geeigneten Zwischensprache (intermediate language oder IL) in den Vordergrund stellt. Idealerweise deckt die IL viele Architekturen ab, hat einen kleinen Befehlssatz und ermöglicht die Entwicklung generischer Analysen, die auf alle Architekturen angewendet werden können. Bisherige Ansätze in der Forschung zur binären Analyse scheitern an der Skalierbarkeit und Stabilität. Diese Dissertation befasst sich mit unserer protoptypischen Implementierung von Mentalese (Sprache des Geistes), ein Framework für architekturunabhängige Analysen ausführbarer Programme. Der Name stammt von der philosophischen Hypothese ab, die von einer Sprache ausgeht, in der Denkprozesse stattfinden. Die Art und Weise, an der wir uns den Problemen der Binäranalyse nähern, entspricht in vielerlei Hinsicht diesem Prozess. Diese deklarative Art der Problemlösung ist eines der Konzepte von Mentalese. Das Design von Mentalese ist so konzipiert, dass es skalierbar, flexibel und leicht erweiterbar ist. Auf der Grundlage dieses Frameworks haben wir Tools entwickelt, die den Exploitation-Prozess unterstützen, eine architekturübergreifende Bug-Suche ermöglichen, sowie auch Bugs erkennen. Contents List of Figures xiii List of Tables xv List of Abbreviations xvii 1 Introduction 1 1.1 Binary Landscape . .3 1.2 Challenges . .4 1.3 Contributions . .5 2 Foundations 9 2.1 The VEX Intermediate Language . 11 2.2 Symbolic Execution: Steps with VEX . 14 2.2.1 Cross-Architecture Basic Block Semantics . 17 2.2.2 Path Extraction for Dynamic Hooks . 21 2.3 A suitable IL . 22 2.3.1 Dataflow Essentials . 26 2.3.2 Static Single Assignment . 28 3 Mentalese - A Binary Analysis Framework 37 3.1 From Datalog to Binary Analysis . 38 3.1.1 Datalog . 39 3.1.2 Knowledgebase: A Mental-IR ................ 41 3.2 Overview . 44 3.3 Frontend . 47 3.3.1 Stack Normalization . 48 3.3.2 SymIL Extensions . 50 3.3.3 Scopes . 51 3.4 Backend . 54 3.4.1 Transition Descriptors . 54 3.4.2 Pointer Analysis . 57 3.4.3 Flow-Sensitivity . 64 ix x Contents 3.4.4 Context-Sensitivity . 65 3.5 Analysis Derivatives . 69 3.5.1 Taint-Analysis . 69 3.5.2 Value Propagation . 74 3.5.3 Slicing . 75 3.6 Experimental Study: Pointer Analysis . 77 4 Towards Automated Generation of Exploitation Primitives for Web Browsers 87 4.1 Model and Assumptions . 89 4.2 Design . 93 4.2.1 Finding Sinks . 95 4.2.2 Program Paths . 96 4.2.3 Triggering Input . 102 4.2.4 Implementation Details . 103 4.3 Evaluation . 103 4.3.1
Recommended publications
  • Serge Kosyrev Curriculum Vitae
    Serge Kosyrev Curriculum vitae ROLE SOUGHT b Zelenograd, Moscow (RU) ) Technologist T +7 (905) 5380951 ) Architect / team lead B kosyrev.serge protonmail com ) Senior software engineer E deepfire.github.io SYSTEM BUILDING EDUCATION 2000-2001 Engineering institute ) a SoC-targeted system software development and National Research University of assurance toolchain (IEEE 1149.1) Electronic Technology, Moscow ) two transpilers (one used in critical production environment) 2002-2006 Business school Institute of International Business ) a package manager and a proto-CI system for a Education, Moscow diverse environment (personal project) ) a hypervisor-based secure endpoint (prototype); the hypervisor was written from scratch PUBLIC PROJECTS 2017 undisclosed project HIGH-LEVEL DECLARATIVE DESIGN a knowledge representation & PROGRAMMING and visualisation tool. Don’t feel like talking about it yet ) pure, typed, functional: to support program rea- 2017 reflex-glfw soning, refactoring and assurance a library facilitating use of Re- • Haskell (expressive higher-kinded & dependent flex FRP with OpenGL/GLFW types, reactive (FRP), lazy evaluation) 2017 Barrelfish OS contributions ) metaprogramming: expanding ability to express Nix-based build environment solutions to very complex problems reproducibility (merged up- • Common Lisp (an extensible compiler) stream), stack traces (work in progress) PROGRAM SEMANTICS, 2015-ONGOING Contributions to Nixpkgs packaging software I need COMPILATION AND ANALYSIS for the NixOS Linux distribu- tion/package repository
    [Show full text]
  • A Multi-System VRML Viewer
    pp g y p y g g g , San Diego, California, Decemb er 1995. VRweb: A Multi-System VRML Viewer Michael Pichler, Gerb ert Orasche, Keith Andrews 1 I ICM, Graz UniversityofTechnology Ed Grossman 2 National Center for Sup ercomputing Applications Mark McCahill 3 University of Minnesota Abstract form of Silicon Graphics' Inventor [27 ] le format, an ex- tensive, proven 3D graphics le format which includes a va- riety of sp ecial-purp ose no des. VRML adopted Inventor's As VRML b ecomes the standard for describing no de-based hierarchical structure, eld syntax and instanc- 3D scenes on the Internet, many VRML viewers ing mechanism, but left out a numb er of its sp ecial-purp ose are b eing develop ed with proprietary interests or and more esoteric features. VRML de nes no des for geom- for sp eci c target systems or proto cols. etry p olygon based and primitive shap es, text, grouping, VRweb is a VRML viewer providing the same multiple levels of detail, transformations elementary and ar- user interface for multiple Web proto cols WWW, bitrary matrices, co ordinates, normal data, prop erties ma- Gopher, and Hyp er-G and multiple platforms terials, textures, rendering attributes bindings and shap e Unix, Windows, and Macintosh and is avail- hints, light sources p ositional, directional, sp ot lights, and able as b oth binary and source co de. VRweb camera de nitions p ersp ective and orthographic. source co de is copyrighted, but is freely avail- The World Wide Web WWW, W3, or \The Web" [8 ], able for non-commercial use, providing a plat- currently the most p opular Internet information system, is form for research and exp eriment.
    [Show full text]
  • Canvas Draw, a 2D Graphics Library
    CD Canvas Draw, A 2D Graphics Library Version 4.4 (cd tecgraf.puc-rio.br) CD (Canvas Draw) is a platform-independent graphics library. It is implemented in several platforms using native graphics libraries: Microsoft Windows (GDI) and X- Windows (XLIB). The library contains functions to support both vector and image applications, and the visualization surface can be either a canvas or a more abstract surface, such as Clipboard, Metafile, PS, and so on. This work was developed at Tecgraf/PUC-Rio by means of the partnership with PETROBRAS/CENPES. CD Project Management: Antonio Escaño Scuri Tecgraf - Computer Graphics Technology Group, PUC-Rio, Brazil http://www.tecgraf.puc-rio.br/cd Overview CD is a platform-independent graphics library. It is implemented in several platforms using native graphics libraries: Microsoft Windows (GDI and GDI+) and X-Windows (XLIB). The library contains functions to support both vector and image applications, and the visualization surface can be either a canvas or a more abstract surface, such as Clipboard, Metafile, PS, and so on. To make the Application Programmers Interface (API) simple, all data are standard C types (int, double or char). Thus the application program does not have to maintain parallel data structures to deal with the graphic library. Furthermore, the list of parameters of the CD primitive functions contains only the geometrical descriptions of the objects (line, circle, text, etc.). Where these objects should appear and what is the their color, thickness, etc. are defined as current state variables stored in the visualization surfaces. That is, the library is visualization-surface oriented, meaning that all attributes are stored in each visualization surface.
    [Show full text]
  • Mesa Documentation Release 12.0
    Mesa Documentation Release 12.0 Brian Paul et al. August 28, 2016 General 1 Introduction 1 2 Developers 7 3 Supported Systems and Drivers9 4 Disclaimer 11 5 Mesa Frequently Asked Questions 13 6 Release Notes 19 7 Acknowledgements 25 8 Conformance 27 9 Downloading 39 10 Compiling and Installing 41 11 Compilation and Installation using Autoconf 45 12 Precompiled Libraries 49 13 Mailing Lists 51 14 Bug Database 53 15 Webmaster 55 16 Shading Language Support 57 17 Mesa EGL 61 18 OpenGL ES 65 19 Environment Variables 67 20 Off-screen Rendering 73 21 Debugging Tips 75 i 22 Performance Tips 77 23 Mesa Extensions 79 24 Function Name Mangling 81 25 llvmpipe 83 26 VMware guest GL driver 87 27 Gallium Post-processing 91 28 Application Issues 93 29 Viewperf Issues 95 30 Code Repository 99 31 Mesa source code tree overview 103 32 Development Utilities 107 33 Help Wanted / To-Do List 109 34 Development Notes 111 35 Source Code Documentation 121 36 GL Dispatch in Mesa 123 37 Indices and tables 127 ii CHAPTER 1 Introduction Mesa is an open-source implementation of the OpenGL specification - a system for rendering interactive 3D graphics. A variety of device drivers allows Mesa to be used in many different environments ranging from software emulation to complete hardware acceleration for modern GPUs. Mesa ties into several other open-source projects: the Direct Rendering Infrastructure and X.org to provide OpenGL support to users of X on Linux, FreeBSD and other operating systems. Project History The Mesa project was originally started by Brian Paul.
    [Show full text]
  • Portal 2 the Dark
    GAMING ON LINUX GAMING ON LINUX The tastiest brain candy to relax those tired neurons TENTACLES OF CTHULU Portal 2 Prepare to return to the Aperture Science Labs. ook out puzzle fans – here comes a big What is left of the labs! Lone! Valve, our new benevolent gaming overlord, has unleashed the Linux beta version of its highly praised sequel to Portal, and Liam Dawe is our Games Editor and the founder of gamingonlinux.com, appropriately named this the home of Tux gaming on the web. beast Portal 2. It was originally released in 2007, and Linux teamOS, from Valve, is a Linux users now get to join in on distribution aimed solely at the fun as Valve pushes more gaming, with Valve’s own S games our way. patches included to increase performance of various systems Something important to Portal 2 is a first-person a co-op mode too, so you can within the distribution. SteamOS was remember is the fact that it is puzzle game involving a solve puzzles with your friends one of the major announcements that in beta, so there will be certain special gun that opens portals – we suggest playing the Valve made in September 2013, bugs and issues you may between two places for you to single-player first. alongside its own gaming controller come across, but it is still well jump through and overcome http://store.steampowered. (the Steam Controller), and also its console-like Steam Machines. The worth a look. obstacles. This sequel includes com/app/620 distribution will be pre-installed on Steam Machines, removing a barrier to Linux adoption.
    [Show full text]
  • Moving to Opengl
    MOVING TO OPENGL Jason Mitchell Dan Ginsburg Rich Geldreich Peter Lohrmann Outline • OpenGL Strategy - Jason • Shipping shaders - Dan • New debugging tools – Rich & Peter You are going to use OpenGL OpenGL is Everywhere • SteamOS • Desktop Linux, OS X & Windows • China overwhelmingly XP but fairly modern hardware • Mobile OpenGL ES is ubiquitous • Even “Big OpenGL” arriving • WebGL Steam Graphics Hardware OpenGL Direct3D Steam Hardware Survey, Dec 2013 Steam OpenGL Drivers Hardware Capability Installed Drivers • Over time, we want the chart on the right to look more like the chart on the left • Some challenges: • Apple currently on 4.1 • Vendors have varying XP support Steam Hardware Survey, Dec 2013 Steam Operating Systems Steam Hardware Survey, Dec 2013 DirectX and Total Available Market GPUs Systems (Windows Vista, 7, 8) DirectX 11 67% 62% DirectX 10.x 96% 86% DirectX 9 100% 100% OpenGL and Total Available Market GPUs Systems OpenGL 4.x 67% 67% OpenGL 3.3 96% 96% OpenGL 2.1 100% 100% Emerging Markets • Valve is expanding beyond its traditional borders • The most recent example is Dota in China • Windows XP is extremely prevalent in China Chinese Cyber Cafe OS Versions No DirectX10 or DirectX11 games for these customers Data from the Yi You cyber cafe platform Dota Users in China • Windows XP very popular • We think this is a lower bound on XP in China • Hardware is modern! • Use OpenGL to access that hardware! Dota users in China January 2014 OpenGL Strategy • Source 2 has multiple rendering backends • OpenGL backend is a peer to others
    [Show full text]
  • 3D Application Debugging Master Dissertation
    Universidade do Minho Escola de Engenharia Departamento de Informatica´ Master Course in Computing Engineering Andre´ Alexandre Wang Liu 3D Application Debugging Master dissertation Supervised by: Antonio´ Jose´ Borba Ramires Fernandes, Braga, November 12, 2014 ACKNOWLEDGEMENTS I would like to sincerely and gratefully thank my adviser Antonio´ Jose´ Borba Ramires Fernandes for all the guidance, patience and understanding in my studies at Universidade do Minho. His interest and help in this thesis was crucial and without it I could not accomplish this work. I would also like to thank all members of Departamento de Informatica for all the knowledge I learned during this course. I would like to thank all my colleagues in AgroSocial for sticking with me and giving me time to make the necessary studies while I worked along in our collaborative project. I also would like to thank all the colleagues I met during my years in Universidade do Minho for all help provided during my student years. Finally I would like to thank my family for supporting my life here in Campus Gualtar for it is their hard work that I could sustain myself so far and it is their hard work that I have reached so far. ABSTRACT It’s rare for a bugless program to exist, this includes 3D applications with their respective shaders. In particular shaders are harder to debug than common applications, since they are loaded to the gpu and executed in thousands of smaller threads simultaneously. It isn’t easy to obtain the variables values, the application state and it’s hard to detect what causes the errors even with posterior correction.
    [Show full text]
  • Mitsuba Documentation Version 0.4.4
    Mitsuba Documentation Version 0.4.4 Wenzel Jakob February 28, 2013 Contents Contents Contents I. Using Mitsuba 7 1. About Mitsuba 7 2. Limitations 8 3. License 8 4. Compiling the renderer 9 4.1. Common steps ......................................... 9 4.1.1. Build conigurations ................................. 9 4.1.2. Selecting a coniguration .............................. 10 4.2. Compilation lags ....................................... 10 4.3. Building on Debian or Ubuntu Linux ............................ 11 4.3.1. Creating Debian or Ubuntu Linux packages ................... 12 4.3.2. Releasing Ubuntu packages ............................. 12 4.4. Building on Fedora Core ................................... 13 4.4.1. Creating Fedora Core packages ........................... 13 4.5. Building on Arch Linux .................................... 13 4.5.1. Creating Arch Linux packages ........................... 14 4.6. Building on Windows ..................................... 14 4.6.1. Integration with the Visual Studio interface ................... 15 4.7. Building on Mac OS X .................................... 15 5. Basic usage 16 5.1. Interactive frontend ...................................... 16 5.2. Command line interface ................................... 16 5.2.1. Passing parameters .................................. 18 5.2.2. Writing partial images to disk ........................... 19 5.2.3. Rendering an animation ............................... 19 5.3. Direct connection server ................................... 19 5.4. Utility
    [Show full text]
  • 3D Application Debugging Master Dissertation
    Universidade do Minho Escola de Engenharia Departamento de Informática Master Course in Computing Engineering André Alexandre Wang Liu 3D Application Debugging Master dissertation Supervised by: António José Borba Ramires Fernandes, Braga, December 21, 2014 ACKNOWLEDGEMENTS I would like to sincerely and gratefully thank my adviser António José Borba Ramires Fernandes for all the guidance, patience and understanding in my studies at Universidade do Minho. His interest and help in this thesis was crucial and without it I would not have accomplished this work. I would also like to thank all members of Departamento de Informática for all the knowledge I accumulated during this course. I would like to thank all my colleagues in AgroSocial for sticking with me and giving me time to make the necessary studies while I worked along in our collaborative project. I also would like to thank all the colleagues I met during my years in Universidade do Minho for all help provided during my student years. Finally I would like to thank my family for supporting my life here in Campus Gualtar for it is their hard work that I could sustain myself so far and it is their hard work that I have reached so far. ABSTRACT It is rare for a bugless program to exist, this includes 3D applications with their respective shaders. In particular shaders are harder to debug than common applications, since they are loaded to the GPU and executed in thousands of smaller threads simultaneously. It is not easy to obtain variables values, the application state and it is hard to detect what causes errors.
    [Show full text]
  • Advanced Linux Game Programming
    Advanced Linux Game Programming Leszek Godlewski Programmer, Nordic Games Nordic Games GmbH • Started in 2011 as a sister company to Nordic Games Publishing (We Sing) • Base IP acquired from JoWooD and DreamCatcher (SpellForce, The Guild, Aquanox, Painkiller) • Initially focusing on smaller, niche games • Acquired THQ IPs in 2013 (Darksiders, Titan Quest, Red Faction, MX vs. ATV) • Now shifting towards being a production company with internal devs • Since fall 2013: internal studio in Munich, Germany (Grimlore Games) 2 Leszek Godlewski Programmer, Nordic Games • Ports ● Painkiller Hell & Damnation (The Farm 51) ● Deadfall Adventures (The Farm 51) ● Darksiders (Nordic Games) • Formerly generalist programmer on PKHD & DA at TF51 3 Objective of this talk Your game engine on Linux, before porting: Missing! 4 Objective of this talk (cont.) Your first “working” Linux port: Oops. Bat-Signal! 5 Objective of this talk (cont.) Where I want to try helping you get to: 6 In other words, from this: 7 To this: 8 And that's mostly debugging All sorts of debuggers! apitrace 9 Demo code available is.gd/GDCE14Linux 10 Intended takeaway ● Build system improvements ● Signal handlers ● Memory debugging with Valgrind ● OpenGL debugging techniques 11 Intended takeaway Agenda ● Build system improvements ● Signal handlers ● Memory debugging with Valgrind ● OpenGL debugging techniques 12 Build systems What I had initially with UE3: ● Copy/paste of the Mac OS X toolchain ● It worked, but... ● Slow ● Huge binaries because of debug symbols ● Problematic linking of circular dependencies 13 Build systems (cont.) ● 32-bit binaries required for feature/hardware parity with Windows ● Original solution: a chroot jail with an entire 32-bit Ubuntu system just for building 14 Cross-compiling for 32/64-bit ● gcc -m32/-m64 is not enough! ● Only sets target code generation ● Not headers & libraries (CRT, OpenMP, libgcc etc.) ● Fixed by installing gcc-multilib ● Dependency package for non-default architectures (i.e.
    [Show full text]