Dissertations / Theses on the topic 'Linux operating system'
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Bartram, Scott A. "Supporting a Trusted Path for the LINUX operating system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA380852.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, June 2000.Thesis advisors: Irvine, Cynthia E. ; Clark, Paul C. "June 2000." Includes bibliographical references (p. 61-63). Also Available online.
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Shelton, Benjamin H. "Popcorn Linux: enabling efficient inter-core communication in a Linux-based multikernel operating system." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23119.
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As manufacturers introduce new machines with more cores, more NUMA-like architectures, and more tightly integrated heterogeneous processors, the traditional abstraction of a monolithic OS running on a SMP system is encountering new challenges. One proposed path forward is the multikernel operating system. Previous efforts have shown promising results both in scalability and in support for heterogeneity. However, one effort\'s source code is not freely available (FOS), and the other effort is not self-hosting and does not support a majority of existing applications (Barrelfish).In this thesis, we present Popcorn, a Linux-based multikernel operating system. While Popcorn was a group effort, the boot layer code and the memory partitioning code are the author\'s work, and we present them in detail here. To our knowledge, we are the first to support multiple instances of the Linux kernel on a 64-bit x86 machine and to support more than 4 kernels running simultaneously.
We demonstrate that existing subsystems within Linux can be leveraged to meet the design goals of a multikernel OS. Taking this approach, we developed a fast inter-kernel network driver and messaging layer. We demonstrate that the network driver can share a 1 Gbit/s link without degraded performance and that in combination with guest kernels, it meets or exceeds the performance of SMP Linux with an event-based web server. We evaluate the messaging layer with microbenchmarks and conclude that it performs well given the limitations of current x86-64 hardware. Finally, we use the messaging layer to provide live process migration between cores.
Master of Science
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Ravichandran, Akshay Giridhar. "Single System Image in a Linux-based Replicated Operating System Kernel." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56654.
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Recent trends in the computer market suggest that emerging computing platforms will be increasingly parallel and heterogeneous, in order to satisfy the user demand for improved performance and superior energy savings. Heterogeneity is a promising technology to keep growing the number of cores per chip without breaking the power wall. However, existing system software is able to cope with homogeneous architectures, but it was not designed to run on heterogeneous architectures, therefore, new system software designs are necessary.
One innovative design is the multikernel OS deployed by the Barrelfish operating system (OS) which partitions hardware resources to independent kernel instances that communicate exclusively by message passing, without exploiting the shared memory available amongst different CPUs in a multicore platform. Popcorn Linux implements an extension of the multikernel OS design, called replicated-kernel OS, with the goal of providing a Linux-based single system image environment on top of multiple kernels, which can eventually run on different ISA processors. A replicated-kernel OS replicates the state of various OS sub-systems amongst kernels that cooperate using message passing to distribute or access various services uniquely available on each kernel.
In this thesis, we present mechanisms to distribute signals, namespaces, inter-thread synchronizations and socket state replication. These features are built on top of the existing messaging layer, process or thread migration and address space consistency protocol to provide the application with an illusion of single system image and developers with the SMP programming environment they are most familiar with. The mechanisms developed were unit tested with micro benchmarks to validate their correctness and to measure the gained speed up or additive overhead. Real-world applications were also used to benchmark the developed mechanisms on homogeneous and on heterogeneous architectures. It is found that the contributed Popcorn synchronization mechanism exhibits overhead compared to vanilla Linux on multicore as Linux's equivalent mechanisms are tightly coupled with underlying hardware cache coherency protocol, therefore, faster than software message passing. On heterogeneous platforms, the developed mechanisms allow to transparently map each portion of the application to the processor in the platform on which the execution is faster. Optimizations are recommended to further improve the performance of the proposed synchronization mechanism. However, optimizations may force the userspace application and libraries to be rewritten in order to decouple their synchronization mechanisms of shared memory, therefore losing transparency, which is one of the primary goals of this work.Master of Science
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Magnusson, Ulf. "A Linux-based, Web-oriented operating system designed to boot quickly." Thesis, Linköpings universitet, RTSLAB - Laboratoriet för realtidssystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73492.
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This thesis describes the design and implementation of a Linux-based, Web-oriented operating system called Awesom-O, designed with a focus on short boot time and small disk footprint. Among other techniques for lowering boot time, a semi-automatic method for generating a Linux kernel of minimal size for a given platform is developed, making use of an interpreter for the Linux kernel’s configuration language, Kconfig. The boot process of the finished system is analyzed to identify limiting factors in lowering its boot time further, and techniques for overcoming these are suggested. Excluding the initial BIOS stage of the boot process, the boot time of the finished system—up until it is idling inside the web browser interface waiting for user input—is 3.8 seconds (2.1 seconds to a shell prompt, 1.7 seconds in the kernel) on an Acer Travelmate 8200 laptop with an Intel Core Duo CPU at 2.0 GHz and a Momentus 5400.2 SATA (ST9120821AS) hard drive; 2.4 seconds (1.6 seconds to a shell prompt, 1.1 seconds in the kernel) on a Celsius M460 workstation with an Intel Core 2 Quad CPU at 2.5 GHz and a Barracuda 7200.11 SATA hard drive (ST3500320AS); 4.6 and 4.0 seconds respectively for the same systems when booting from a USB 2.0 device (a ChipsBank CBM2080 USB 2.0 stick); and 12.6 seconds on the BeagleBoard (8 seconds in the bootloader—an obvious area for future improvement). The Web functionality in Awesom-O is implemented atop the Opera Linux Devices SDK: a software framework for integrating web browser functionality in small Linux-based systems.
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Braithwaite, Stephen. "Queuing disciplines on Linux made easy." University of Southern Queensland, Faculty of Sciences, 2006. http://eprints.usq.edu.au/archive/00001280/.
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[Abstract]: This is a project to implement a Mice and Elephants queueing discipline, which favoursshort flows over long flows, on Linux. The project has three aims. The first aim is toproduce a prototype Mice and Elephants router for the purpose of further evaluation ofthe Mice and Elephants strategy and the Shortest Job First strategy. The second aim is tomake a contribution to Linux by making my implementation as code that is both fit fordistribution with Linux and useful in a small business or domestic setting. The third aimis to explore and document a method of creating Linux queueing disciplines in general.
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Boman, Simon, and Olof Rutgersson. "Replacing OSE with Real Time capable Linux." Thesis, Department of Computer and Information Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18128.
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For many years OSE has been a common used operating system, with real time extensions enhancements, in embed-ded systems. But in the last decades, Linux has grown and became a competitor to common operating systems and, in recent years, even as an operating system with real time extensions. With this in mind, ÅF was interested in replacing the quite expensive OSE with some distribution of the open source based Linux on a PowerPC MPC8360. Therefore, our purpose with thesis is to implement Linux on the named platform and make some tests to see if it is possible to replace OSE with Linux. Using Linux has several advantages, for example it is free of charge to use and over the years the popularity of Linux within the developer community has resulted in numerous tools and utilities available for free.
As a result, this study shows that Linux with real time extensions on the MPC8360 PowerPC platform is a viable alternative to OSE regarding cost efficiency, flexibility, adaptability and competence available on the market.
Further studies can be done towards benchmarking for I/O systems and implementing support for more hardware on the MPC8360 AF platform.
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Öberg, Jonas. "Comparative study of operating system security using SELinux and Systrace." Thesis, University of Kalmar, School of Communication and Design, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-2015.
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This thesis makes a comparative study of the security systemsSystrace (used primarily with OpenBSD) and SELinux (usedexclusively with Linux), trying to answer the question as to whichtype of security is offered by each respective system, and wheneach should be used. The key difference between SELinux andSystrace seems to be their mode of operation, where SELinux,built around the LSM framework in the Linux kernel, works withtype enforcement on files, sockets and other objects, whereasSystrace works on a strict system call basis. The two systems areseen to serve two different purposes which sometimes overlap,but in just as many cases provide solutions for entirely differentquality priorities.
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Yi, Long. "KernTune: self-tuning Linux kernel performance using support vector machines." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6921_1249280496.
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Self-tuning has been an elusive goal for operating systems and is becoming a pressing issue for modern operating systems. Well-trained system administrators are able to tune an operating system to achieve better system performance for a specific system class. Unfortunately, the system class can change when the running applications change. The model for self-tuning operating system is based on a monitor-classify-adjust loop. The idea of this loop is to continuously monitor certain performance metrics, and whenever these change, the system determines the new system class and dynamically adjusts tuning parameters for this new class. This thesis described KernTune, a prototype tool that identifies the system class and improves system performance automatically. A key aspect of KernTune is the notion of Artificial Intelligence oriented performance tuning. Its uses a support vector machine to identify the system class, and tunes the operating system for that specific system class. This thesis presented design and implementation details for KernTune. It showed how KernTune identifies a system class and tunes the operating system for improved performance.
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Procházka, Boris. "Útoky na operační systém Linux v teorii a praxi." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237139.
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This master's thesis deals with Linux kernel security from the attacker's point of view. It maps methods and techniques of disguising the computing resources used by today's IT pirates. The thesis presents a unique method of attack directed on the system call interface and implemented in the form of two tools (rootkits). The thesis consists of a theoretical and a practical part. Emphasis is placed especially on the practical part, which manifests the presented information in the form of experiments and shows its use in real life. Readers are systematically guided as far as the creation of a unique rootkit, which is capable of infiltrating the Linux kernel by a newly discovered method -- even without support of loadable modules. A part of the thesis focuses on the issue of detecting the discussed attacks and on effective defence against them.
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Luštický, Josef. "40GbE směrovač pro operační systém GNU/Linux." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2015. http://www.nusl.cz/ntk/nusl-234945.
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Účelem této práce je popis protokolu 40Gb Ethernet, popis směrovacího procesu v jádře Linux a navrhnout a provést testování výkonnosti směrování se síťovým adaptérem pro 40Gb Ethernet. Výsledky a nastavení pro získání maximální výkonnosti směrování jsou dále popsány v této práci.
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Kalidindi, Srinivas R. "Linux Operating System Configuration Management Framework: A Scalable and Efficient Approach Using Open Source Utilities." Ohio : Ohio University, 2007. http://www.ohiolink.edu/etd/view.cgi?ohiou1193950374.
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Bahmann, Helge. "A network transparent, retained mode multimedia processing framework for the Linux operating system environment." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:bsz:105-967869.
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Die Arbeit präsentiert ein Multimedia-Framework für Linux, das im Unterschied zu früheren Arbeiten auf den Ideen "retained-mode processing" und "lazy evaluation" basiert: Statt Transformationen unmittelbar auszuführen, wird eine abstrakte Repräsentation aller Medienelemente aufgebaut. "renderer"-Treiber fungieren als Übersetzer, die diese Darstellung zur Laufzeit in konkrete Operationen umsetzen, wobei das Datenmodell zahlreiche Optimierungen zur Reduktion der Anzahl der Schritte oder der Minimierung von Kommunikation erlaubt. Dies erlaubt ein stark vereinfachtes Programmiermodell bei gleichzeitiger Effizienzsteigerung. "renderer"-Treiber können zur Ausführung von Transformationen den lokalen Prozessor verwenden, oder können die Operationen delegieren. In der Arbeit wird eine Erweiterung des X Window Systems um Mechanismen zur Medienverarbeitung vorgestellt, sowie ein "renderer"-Treiber, der diese zur Delegation der Verarbeitung nutzt.
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Brock, Jerome P. "Supporting the secure halting of user sessions and processes in the Linux operating system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA393629.
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Kacar, Mehmet Nazir. "A Soho Router Implementation On Motorola Mcf5272 Processor And Uclinux Operating System." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1123884/index.pdf.
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Recently, various special purpose processors have been developed and are
frequently being used for different specialized tasks. Prominent among these are the
communication processors, which are generally used within an embedded system
environment. Such processors can run relatively advanced and general purpose
operating systems such as uCLinux, which is a freely available embedded Linux
distribution. In this work, a prototype SoHo (Small office / Home office) router is
designed and implemented using Motorola MCF5272 as the core communication
processor and uCLinux as the operating system. The implementation relies purely
on the existing hardware resources of an available development board and the
publicly available open source utilities of uCLinux. The overall development
process provides an embedded system implementation and configuration example.
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Bissyande, Tegawende. "Contributions for improving debugging of kernel-level services in a monolithic operating system." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00821893.
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Alors que la recherche sur la qualité du code des systèmes a connu un formidable engouement, les systèmes d'exploitation sont encore aux prises avec des problèmes de fiabilité notamment dus aux bogues de programmation au niveau des services noyaux tels que les pilotes de périphériques et l'implémentation des systèmes de fichiers. Des études ont en effet montré que chaque version du noyau Linux contient entre 600 et 700 fautes, et que la propension des pilotes de périphériques à contenir des erreurs est jusqu'à sept fois plus élevée que toute autre partie du noyau. Ces chiffres suggèrent que le code des services noyau n'est pas suffisamment testé et que de nombreux défauts passent inaperçus ou sont difficiles à réparer par des programmeurs non-experts, ces derniers formant pourtant la majorité des développeurs de services. Cette thèse propose une nouvelle approche pour le débogage et le test des services noyau. Notre approche est focalisée sur l'interaction entre les services noyau et le noyau central en abordant la question des "trous de sûreté" dans le code de définition des fonctions de l'API du noyau. Dans le contexte du noyau Linux, nous avons mis en place une approche automatique, dénommée Diagnosys, qui repose sur l'analyse statique du code du noyau afin d'identifier, classer et exposer les différents trous de sûreté de l'API qui pourraient donner lieu à des fautes d'exécution lorsque les fonctions sont utilisées dans du code de service écrit par des développeurs ayant une connaissance limitée des subtilités du noyau. Pour illustrer notre approche, nous avons implémenté Diagnosys pour la version 2.6.32 du noyau Linux. Nous avons montré ses avantages à soutenir les développeurs dans leurs activités de tests et de débogage.
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Nilsson, Christoffer, and Marcus Nilsson. "Installationsgränssnitt under Linux och Windows XP utifrån ISO 9241." Thesis, Blekinge Tekniska Högskola, Avdelningen för för interaktion och systemdesign, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3955.
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This thesis investigates how different Linux-distributions installation interface relate to the ISO 9241 standard, parts 12 and 13, and how they relate to the installation interface of Windows XP, with the hypothesis: "There is a Linux-distribution whose installation interface according to applicable HCIrecommendations is equivalent to that of Windows XP." With the checklists provided by ISO 9241 an empirical study has been made, and so comparable measurements of how well the Linux-distributions and Windows XP follows the recommendations of the standard was obtained. By comparing the results from the tests similarities and differences between the installation interfaces can be deducted. As the result and the conclusion shows there are Linux-distributions whose installation interface, according to the applicable HCI-recommendations, are equivalent to that of Windows XP.
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Brejcha, Martin. "Vývoj ovladače pro zákaznický analogový uživatelský modul v OS Linux." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218140.
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This master's thesis describes how to develop loable kernel module for operating system Linux. Module can be use like driver for concrete hardware device. In this case for telecommunication hardware. The second part of this thesis describes how to implement support for this hardware in Asterisk PBX. Support in Asterisk is realized by channel module. In that channel module are implemented functions for process incoming and dialed calls.
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Glover, Mark V. "Integrating a trusted computing base extension server and secure session server into the Linux operating system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA397015.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, Sept. 2001.Thesis advisors: Irvine, Cynthia E. ; Shifflett, David. "September 2001." Includes bibliographical references (p. 61-62). Also Available online.
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Casagrande, Luiz Gustavo. "Soft error analysis with and without operating system." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/149633.
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A complexidade dos sistemas integrados em chips bem como a arquitetura de processadores comerciais vem crescendo dramaticamente nos últimos anos. Com isto, a dificuldade de avaliarmos a suscetibilidade às falhas em decorrência da incidência de partículas espaciais carregadas nestes dispositivos cresce com a mesma taxa. Este trabalho apresenta uma análise comparativa da susceptibilidade à erros de software em um microprocessador embarcado ARM Cortex-A9 single core de larga escala comercial, amplamente utilizado em aplicações críticas, executando um conjunto de 11 aplicações desenvolvidas para um ambiente bare metal e para o sistema operacional Linux. A análise de soft errors é executada por injeção de falhas na plataforma de simulação OVPSim juntamente com o injetor OVPSim-FIM, capaz de sortear o momento e local de injeção de uma falha. A campanha de injeção de falhas reproduz milhares de bit-flips no banco de registradores do microprocessador durante a execução do conjunto de benchmarks que possuem um comportamento de código diverso, desde dependência de fluxo de controle até aplicações intensivas em dados. O método de análise consiste em comparar execuções da aplicação onde falhas foram injetadas com uma execução livre de falhas. Os resultados apresentam a taxa de falhas que são classificadas em: mascaradas (UNACE), travamento ou perda de controle de fluxo (HANG) e erro nos resultados (SDC). Adicionalmente, os erros são classificados por registradores, separando erros latentes por sua localização nos resultados e por exceções detectadas pelo sistema operacional, provendo novas possibilidades de análise para um processador desta escala. O método proposto e os resultados obtidos podem ajudar a orientar desenvolvedores de software na escolha de diferentes arquiteturas de código, a fim de aprimorar a tolerância à falhas do sistema embarcado como um todo.The complexity of integrated system on-chips as well as commercial processor’s architecture has increased dramatically in recent years. Thus, the effort for assessing the susceptibility to faults due to the incidence of spatial charged particles in these devices has growth at the same rate. This work presents a comparative analysis of soft errors susceptibility in the commercial large-scale embedded microprocessor ARM Cortex-A9 single core, widely used in critical applications, performing a set of 11 applications developed for a bare metal environment and the Linux operating system. The soft errors analysis is performed by fault injection in OVPSim simulation platform along with the OVPSim-FIM fault injector, able to randomly select the time and place to inject the fault. The fault injection campaign reproduces thousands of bit-flips in the microprocessor register file during the execution of the benchmarks set, with a diverse code behavior ranging from control flow dependency to data intensive applications. The analysis method is based on comparing applications executions where faults were injected with a fault-free implementation. The results show the error rate classified by their effect as: masked (UNACE), crash or loss of control flow (HANG) and silent data corruption (SDC); and by register locations. By separating latent errors by its location in the results and exceptions detected by the operating system, one can provide new better observability for a large-scale processor. The proposed method and the results can guide software developers in choosing different code architectures in order to improve the fault tolerance of the embedded system as a whole.
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Koya, Bharath Kumar. "Sched-ITS: An Interactive Tutoring System to Teach CPU Scheduling Concepts in an Operating Systems Course." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1495656458526149.
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Rabbani, Talvia. "Empirical Testing of the CySeMoL Tool for Cyber Security Assessment – Case Study of Linux Server and MySQL." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187664.
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In this Master Thesis, several common applications used with MySQL and Linux server are modelled using the Enterprise Architecture Analysis Tool (EAAT) and the Cyber Security Modelling Language (CySeMoL), both developed by the Department of Industrial Information and Control System (ICS) at KTH. The objective of this study is to use the CySeMoL tool to evaluate the feasibility and correctness of the tool by simulating some particular type of attacks on a real life Linux server. A few common applications with MySQL on a Linux server and two Linux operating system services are modelled and explained together with their detailed information and defense mechanisms. A real life penetration test has then been carried out in order to validate the simulated results from the tool. The results of the analysis suggest that the security vulnerability predictions done by CySeMoL on a Linux server has good predictive performance.I denna Masteruppsats modelleras ett antal vanliga applikationer på en MySQL- och Linuxplattform med hjälp av Enterprise Architecture Analysis Tool (EAAT) tillsammans med Cybersecurity Modeling Language (CySeMoL). Båda dessa är utvecklade vid avdelningen för industriella informations- och styrsystem (ICS) på KTH. Syftet med denna studie är att validera korrektheten av CySeMoL-verktygets sårbarhetsprediktioner genom att simulera ett antal specifika cyberattacker mot en Linuxplattform. Ett antal vanligt förekommande applikationer på en MySQL-plattform samt två operativsystemstjänster i en Linuxserver modelleras. Penetrationstest utförs därefter för att validera resultaten som simuleras i CySeMoL-verktyget. Studien visar att CySeMols förutsägelser stämmer väl med resultaten av penetrationstesterna.
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Pokorný, Fridolín. "Optimalizace výkonu VPN v Linuxu." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2016. http://www.nusl.cz/ntk/nusl-255416.
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Tato práce se zabývá analýzou stávajících a aktivních VPN řešení, jejich výkonu a slabých stránek. Výsledkem práce je jaderný modul pro Linux, který implementuje datový přenos pomocí protokolů TLS a DTLS na základě konfigurace ustanoveného spojení v chráněném režimu. Primárním cílem bylo odstranit datové kopie a změny kontextu z chráněného režimu do režimu jádra během datových přenosů ve VPN řešeních založených na protokolech TLS a DTLS. Práce analyzuje cenu těchto operací a na základě analýz lokalizuje další kroky nutné k využití implementovaného jaderného modulu ve VPN řešeních. Práce se dále zabývá analýzou dalších možných využití implementovaného jaderného modulu mimo VPN řešení.
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Somanathan, Muthuveer. "An initial operating system adaptation heuristic for Swap Cluster Max (SCM)." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Souza, Osvaldo de. "Metodologia para porte do sistema operacional Linux para sistemas embarcados." reponame:Repositório Institucional da UFC, 2007. http://www.repositorio.ufc.br/handle/riufc/16065.
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SOUZA, O. Metodologia para porte do sistema operacional Linux para sistemas embarcados. 2007. 78 f. Dissertação (Mestrado em Engenharia de Teleinformática) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2007.Submitted by Marlene Sousa (mmarlene@ufc.br) on 2016-04-05T12:10:56Z No. of bitstreams: 1 2007_dis_osouza.pdf: 947735 bytes, checksum: 7e9a83068dadae0c7e247ec7883cd3fc (MD5)
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Embedded system development frequently uses the “trial and error” approach for Operating System (OS) porting,resulting in incomplete or inconsistent porting. In this work, we present a pioneer work addressing this issue. We propose a complete method for detecting OS parts that should be adjusted in order to port the OS into a new hardware platform. The proposed method combines information from the OS source-code and peculiarities of the new hardware platform, resulting in: a complete list of source-codes that must be adjusted; the interdependence between these source-codes; the priority order of modifications for each source-code; and an effort-based schedule to help planning the modifications. In addition, we propose an algorithm dealing with source-code’s cyclic references. Finally, we present a study-case based on an application developed according the proposed method.
Em projetos de desenvolvimento de sistemas embarcados normalmente adota-se uma abordagem de “tentativa e erro” nas atividades relacionadas ao porte do sistema operacional(SO), resultando em um porte incompleto ou inconsistente. Nesta pesquisa apresenta-se um trabalho original onde se propõe uma solução para esta abordagem através de uma metodologia completa para a detecção das partes do SO que devem ser ajustadas de forma que o SO seja portado para a nova plataforma de hardware. A metodologia proposta combina as informações do código-fonte do SO e as particularidades do novo hardware, resultando em: uma lista completa do código-fonte que deve ser ajustado; a interdependência entre estes códigos-fonte; a ordem de prioridade de modificação para cada código-fonte; e um cronograma baseado em esforço, para auxiliar o planejamento das modificações. Adicionalmente, propõe-se um algoritmo para a resolução de referências cíclicas em arquivos de código-fonte. Por fim, é apresentado um estudo de caso baseado em uma aplicação desenvolvida segundo a metodologia proposta.
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Kriesten, Daniel. "Systementwurf eingebetteter heterogener rekonfigurierbarer Systeme mit Linux-Betriebssystem am Beispiel einer modularen Plattform zur Erfassung und Verarbeitung von Sensordaten." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-154966.
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Ausgehend von einer modularen Plattform zur Erfassung und Verarbeitung von Sensordaten bereichert die vorliegende Dissertationsschrift den Systementwurf eingebetteter Systeme um neue Facetten. Ihr besonderer Fokus liegt dabei auf rekonfigurierbaren Architekturen und Linux-basierten Systemen. Ein wesentlicher Beitrag ist die Darstellung und Diskussion von Konzepten und Architekturen vorgenannter Systeme durch ihre Betrachtung auf einer hohen Abstraktionsebene. Dazu schafft die Arbeit ein umfassendes Verständnis für Kommunikation und Konfiguration in heterogenen rekonfigurierbaren Systemen und überträgt die Erkenntnisse auf das Linux-Betriebssystem. Es erfolgt außerdem eine systematische Darstellung der etablierten Zusammenhänge und Abläufe beim Software-, Paket- und Versionsmanagement im Linux-Umfeld. Zur Verbesserung des Entwurfsflusses werden Konzepte und ein geeignetes Werkzeug zur High-Level Spezifikation von Linux-Systemen dargestellt. Die in der Arbeit gewonnenen wissenschaftlichen Erkenntnisse werden hinsichtlich praktischer Relevanz evaluiert und durch prototypische Implementierungen verifiziertBased on a modular platform for recording and processing of sensor data the present thesis enriches the field of system design of embedded systems with new facets. Its particular focus is on reconfigurable architectures and Linux-based systems. A major contribution is the presentation and discussion of concepts and architectures of aforementioned systems by investigating them on a high level of abstraction. To achieve this, the work creates a comprehensive understanding of communication and configuration in heterogeneous reconfigurable systems. This knowledge is transferred on the Linux operating system. In addition, a systematic presentation of the established relationships and processes in software, package and version management in the Linux environment takes place. To improve the design flow of Linux systems, the thesis presents appropriate concepts as well as a tool for high-level specification of embedded Linux systems. The gained scientific findings are evaluated in terms of practical relevance and verified by prototype implementations
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Liu, Zhen. "A lightweight intrusion detection system for the cluster environment." Master's thesis, Mississippi State : Mississippi State University, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07102003-152642/unrestricted/ZhenLiu%5Fthesis.pdf.
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Johansson, Gustav. "Real-Time Linux Testbench on Raspberry Pi 3 using Xenomai." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-235484.
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Test benches are commonly used to simulate events to an embedded system for validation purposes. Microcontrollers can be used for making test benches and can be programmed with a bare-metal style, i.e. without an Operating System (OS), for simple cases. If the test bench would be too complex for a microcontroller, then a Real-Time Operating System (RTOS) could be used instead of a more complex hardware. A RTOS has limited functionalities to guarantee high predictability. A General-Purpose Operating System (GPOS) has a vast number of functionalities but has low predictability. The literature study looks therefore into approaches to improve the real-time predictability of Linux. The result of the literature study finds an approach called Xenomai Cobalt to be the optimal solution, considering the target usecase and project resources. The Xenomai Cobalt approach was evaluated on a Raspberry Pi (RPi) 3 using its General-Purpose Input/Output (GPIO) pins and a latency test. An application was written using Xenomai's Application Programming Interface (API). The application used the GPIO pins to read from a function generator and to write to an oscilloscope. The measurements from the oscilloscope were then compared to the measurements done by the application. The result showed the measured dierences between the RPi 3 and the oscilloscope. The result of the measurements showed that reading varied 66:20 μs, and writing varied 56:20 μs. The latency test was executed with a stress test and the worst measured latency was 82 μs. The resulting measured dierences were too high for the project requirements. However, the majority of the measurements were much smaller than the worstcases with 23:52 μs for reading and 34:05 μs for writing. This means the system could be used better as a rm real-time system instead of a hard real-time system.Testbänkar används ofta för att simulera händelser till ett inbyggt system för validering. Till simpla testbänkar kan mikrokontroller användas. För mer avancerade testbänkar kan RTOS användas på mer komplex hårdvara. RTOS har begränsad funktionalitet för att garantera en hög förutsägbarhet. GPOS har stora mängder funktionaliteter men har istället en låg förutsägbarhet.Litteraturstudien undersökte därför möjligheterna till att få Linux att hantera realtid. Resultatet av litteraturstudien fann ett tillvägagångssätt vid namn Xenomai Cobalt att vara den optimala lösningen för att få Linux till Real-Time Linux.Xenomai Cobalt utvärderades på en RPi 3 med hjälp av dess GPIO-pinnar och ett fördröjningstest. En applikation skrevs med Xenomai’s API. Applikationen använde GPIO-pinnarna till att läsa från en funktionsgenerator och till att skriva till ett oskilloskop. Mätningarna från oskilloskopet jämfördes sen med applikationens mätningar.Resultatet visade mätskillnaderna mellan RPi 3 och oskilloskopet med systemet i viloläge. Resultatet av mätningarna visade att läsningen varierade med 66.20 µs och skrivandet med 56.20 µs. Fördröjningstestet utfördes medstresstestning och visade den värsta uppmätta fördröjningen, resultatet blev82 µs.De resulterande mätskillnaderna blev dock för höga för projektets krav. Majoriteten av mätningarna var mycket mindre än de värsta fallen med 23.52 µs för läsning och 34.05 µs för skrivning. Detta innebar att systemet kan användas med bättre precision som ett fast realtidssystem istället för ett hårt realtidssystem.
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Lorrillere, Maxime. "Caches collaboratifs noyau adaptés aux environnements virtualisés." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066036/document.
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Avec l'avènement du cloud computing, la virtualisation est devenue aujourd'hui incontournable. Elle offre isolation et flexibilité, en revanche elle implique une fragmentation des ressources, et notamment de la mémoire. Les performances des applications qui effectuent beaucoup d'entrées/sorties (E/S) en sont particulièrement impactées. En effet, celles-ci reposent en grande partie sur la présence de mémoire libre, utilisée par le système pour faire du cache et ainsi accélérer les E/S. Ajuster dynamiquement les ressources d'une machine virtuelle devient donc un enjeu majeur. Dans cette thèse nous nous intéressons à ce problème, et nous proposons Puma, un cache réparti permettant de mutualiser la mémoire inutilisée des machines virtuelles pour améliorer les performances des applications qui effectuent beaucoup d'E/S. Contrairement aux solutions existantes, notre approche noyau permet à Puma de fonctionner avec les applications sans adaptation ni système de fichiers spécifique. Nous proposons plusieurs métriques, reposant sur des mécanismes existants du noyau Linux, qui permettent de définir le niveau d'activité « cache » du système. Ces métriques sont utilisées par Puma pour automatiser le niveau de contribution d'un noeud au cache réparti. Nos évaluations de Puma montrent qu'il est capable d'améliorer significativement les performances d'applications qui effectuent beaucoup d'E/S et de s'adapter dynamiquement afin de ne pas dégrader leurs performancesWith the advent of cloud architectures, virtualization has become a key mechanism for ensuring isolation and flexibility. However, a drawback of using virtual machines (VMs) is the fragmentation of physical resources. As operating systems leverage free memory for I/O caching, memory fragmentation is particularly problematic for I/O-intensive applications, which suffer a significant performance drop. In this context, providing the ability to dynamically adjust the resources allocated among the VMs is a primary concern.To address this issue, this thesis proposes a distributed cache mechanism called Puma. Puma pools together the free memory left unused by VMs: it enables a VM to entrust clean page-cache pages to other VMs. Puma extends the Linux kernel page cache, and thus remains transparent, to both applications and the rest of the operating system. Puma adjusts itself dynamically to the caching activity of a VM, which Puma evaluates by means of metrics derived from existing Linux kernel memory management mechanisms. Our experiments show that Puma significantly improves the performance of I/O-intensive applications and that it adapts well to dynamically changing conditions
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Kriesten, Daniel. "Systementwurf eingebetteter heterogener rekonfigurierbarer Systeme mit Linux-Betriebssystem am Beispiel einer modularen Plattform zur Erfassung und Verarbeitung von Sensordaten." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2013. https://monarch.qucosa.de/id/qucosa%3A20141.
Full textAbstract:
Ausgehend von einer modularen Plattform zur Erfassung und Verarbeitung von Sensordaten bereichert die vorliegende Dissertationsschrift den Systementwurf eingebetteter Systeme um neue Facetten. Ihr besonderer Fokus liegt dabei auf rekonfigurierbaren Architekturen und Linux-basierten Systemen. Ein wesentlicher Beitrag ist die Darstellung und Diskussion von Konzepten und Architekturen
vorgenannter Systeme durch ihre Betrachtung auf einer hohen Abstraktionsebene. Dazu schafft die Arbeit ein umfassendes Verständnis für Kommunikation und Konfiguration in heterogenen rekonfigurierbaren Systemen und überträgt die Erkenntnisse auf das Linux-Betriebssystem. Es erfolgt außerdem eine systematische Darstellung der etablierten Zusammenhänge und Abläufe beim
Software-, Paket- und Versionsmanagement im Linux-Umfeld. Zur Verbesserung des Entwurfsflusses werden Konzepte und ein geeignetes Werkzeug zur High-Level Spezifikation von Linux-Systemen dargestellt. Die in der Arbeit gewonnenen wissenschaftlichen Erkenntnisse werden hinsichtlich praktischer Relevanz evaluiert und durch prototypische Implementierungen verifiziert.Based on a modular platform for recording and processing of sensor data the present thesis enriches the field of system design of embedded systems with new facets. Its particular focus is on reconfigurable architectures and Linux-based systems. A major contribution is the presentation and discussion of concepts and architectures of aforementioned systems by investigating them on a high level of abstraction. To achieve this, the work creates a comprehensive understanding of communication and configuration in heterogeneous reconfigurable systems. This knowledge is transferred on the Linux operating system. In addition, a systematic presentation of the established relationships and processes in software, package and version management in the Linux environment takes place. To improve the design flow of Linux systems, the thesis presents appropriate concepts as well as a tool for high-level specification of embedded Linux systems. The gained scientific findings are evaluated in terms of practical relevance and verified by prototype implementations.
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Rácek, Luboš. "Možnosti zabezpečení mezi-procesorové komunikace pro dedikovaná zařízení." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242022.
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Diploma thesis focuses on introduce problematic issue of inter-core communication, implementation of Linux distribution made by project Yocto on chosen platform of NXP i.MX microcontrolers family and solution for secured inter-core communication.
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Carbone, Martim d'Orey Posser de Andrade. "Framework de Kernel para um sistema de segurança imunologica." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276520.
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Orientador: Paulo Licio de GeusDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
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Resumo: O crescimento alarmante da quantidade e da sofisticação dos ataques aos quais estão sujeitos os sistemas computacionais modernos traz à tona a necessidade por novos sistemas de segurança mais eficientes. Na natureza, há um sistema biológico que realiza esta tarefa com notável eficácia: o sistema imunológico humano. Este sistema é capaz de garantir a sobrevivência de um ser humano por décadas, além de ser capaz de aprender sobre novas ameaças e criar defesas para combatê-Ias. Sua eficácia, somada à semelhança entre o cenário da segurança biológica e o da segurança computacional, motivou a criação do projeto Imuno, cujo objetivo é a construção de um sistema de segurança para computadores baseado nos princípios do sistema imunológico humano. Após o estudo inicial, a modelagem conceitual do sistema e a implementação de protótipos restritos de certas funcionalidades do sistema Imuno, este trabalho tem como objetivo avançar rumo à construção de um sistema de segurança imunológico completo, de escopo geral. Para isso, torna-se necessária a implementação de uma framework em nível de sistema operacional, que suporte as funcionalidades relacionadas à prevenção, detecção e resposta que serão utilizadas por este sistema de segurança. Projetada para o kernel Linux 2.6, esta framework é composta por algumas frameworks pré-existentes, como Lima Security Modules (LSM), Netfilter, Class-based Kernel Resource Management (CKRM), BSD Secure Levels (SEClvl) e UndoFS, ajustadas de acordo com os requisitos levantados para a framework; e somadas a uma nova arquitetura de ganchos multifuncionais. Esta arquitetura expande a infraestrutura nativa dos ganchos LSM, tornando-os flexíveis e genéricos o bastante para serem utilizados com outras funcionalidades de segurança além de controle de acesso, como detecção e resposta, além de poderem ser controlados do espaço de usuário em tempo real. Um protótipo foi implementado para a versão 2.6.12 do Linux e submetido a testes, visando avaliar tanto o impacto de desempenho gerado como também o seu comportamento em um cenário de ataque simulado. Os resultados destes testes são expostos no final deste trabalho, junto com as conclusões gerais sobre o projeto e propostas de extensão
Abstract: The alarming growth in the quantity and the sophistication of the attacks that threaten modem computer systems shows the need for new, more efticient security systems. In nature, there is a biological system that accomplishes this task with a remarkable efticiency: the human immune system. Not only this system is capable of assuring the survival of a human being for decades; it is also capable of learning about new threats and creating defenses to fight them. Its efticiency, combined with the similarity that exists between the biological and the computer security problems, has motivated the creation of the Imuno project, whose goal is the construction of a computer security system based on the principIes of the human immune system. After initial studies, the system's conceptual modeling and the implementation of prototypes of certain Imuno functionalities, this project's goal is to advance towards the construction of a complete, general scope immune security system. In order to accomplish that, the implementation of an operating system leveI framework that supports the prevention, detection and response security functionalities to be used by such a system is necessary. Designed for the 2.6 Linux kernel, this framework is composed of several pre-existing frameworks, such as Linux Security Modules (L8M), Netfilter, Class-based Kernel Resource Management (CKRM), BSD Secure Levels (8EClvl) and UndoFS, adjusted according to the framework requirements; and supplemented by a new multifunctional hook architecture. This architecture expands L8M's native hook infrastructure, making them flexible and generic enough to be used by other security functionalities beyond access control, such as detection and response, and also capable of being controlled from userspace in real-time. A prototype has been implemented for Linux version 2.6.12 and submitted to various tests, aiming to evaluate the performance overhead it creates and its behavior in a simulated attack situation. These tests' results are shown at the end of this document, along with a general conclusion about the project and extension proposals
Mestrado
Mestre em Ciência da Computação
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Piano, Matteo. "Multi-Architecture Binary Rewriter to Prevent ROP Arbitrary Code Execution." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-220524.
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Despite the increasing attention to the topic of computer security, the amount of vulnerable software services is still high. The exploitation of a common vulnerability like memory management bugs brought to the development of an attack known as Return Oriented Programming (ROP). Such technique employs malicious memory injections to hijack the control flow of the targeted application and execute an arbitrary series of instructions. This thesis explores the design and implementation of a static binary rewriting tool able to instrument applications compiled for the Linux operating system in order to offer protection against ROP exploitation on x86 and ARM platforms. The instrumentation is achieved by extracting re-compilable assembler code from executable binary files which is then processed and modified. The effectiveness of such solution is tested with a selection of benchmarking utilities in order to evaluate the cost in terms of performance caused by its employment. The results obtained from these experiments show that on average the added overheads are acceptably low and, consequently, the proposed tool is a valid solution to improve the security of vulnerable applications when the original source code is not available.Trots den ökande uppmärksamheten på ämnet datasäkerhet är mängden sårbara mjukvarutjänster fortfarande stor. Utnyttjandet av en vanlig sårbarhet som minneshanteringsfel har lett till utvecklingen av en attack som kallas Return Oriented Programming (ROP). Denna teknik utnyttjar skadliga minnesinjektioner för att ändra kontrollflödet för den riktade applikationen och utföra en godtycklig serie instruktioner. Detta exjobb undersöker utformningen och genomförandet av ett verktyg för statisk binär omskrivning som kan användas för att instrumentera applikationer för Linux-operativsystemet för att erbjuda skydd mot ROP-exploatering på x86- och ARM-plattformar. Instrumentering uppnås genom att extrahera återkompilerbar assemblerkod från exekverbara binära filer som sedan behandlas och modifieras. Effektiviteten av sådan lösning testas med ett urval av benchmarkingverktyg för att utvärdera kostnaden när det gäller prestanda som orsakas av dess användning. Resultaten från dessa experiment visar att de extra kostnaderna i genomsnitt är acceptabelt låga och, följaktligen, är det föreslagna verktyget en giltig lösning för att förbättra säkerheten för sårbara applikationer när den ursprungliga källkoden inte är tillgänglig.
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RAO, SUDHINDRA R. "DATA MANAGEMENT IN DEFER CACHE - IMPLEMENTATION AND ANALYSIS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1066409021.
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Skopal, Jakub. "Problematika přechodu od jednojádrové k vícejádrové implementaci operačního systému." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-363733.
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This thesis deals with the modifications of the hardware design and operating systems of the ZedBoard multi-core platform so that both ARM Cortex A9 processor cores included in SoC Zynq7000 can be used. It analyses the general issue of the multi-core environment and the core functions of the kernel and the operating system. It describes selected means of implementation ZedBoard and FreeRTOS. In the implementation section, specific steps are demonstrated to convert a single-core operating system to a multi-core system but also steps required to run two different operating systems on two processor cores. In the last section all achieved results are summarized.
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Ataide, Fernando Henrique. "Proposta de melhoria de tempo de resposta para o protocolo FTT-CAN : estudo de caso em aplicação automotiva." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/49296.
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Nos últimos anos os sistemas embarcados tem-se tornado notório nos mercados de eletroeletrônicos de consumo, automação industrial e comercial e em veículos em geral. Grande parte destas aplicações possui restrições temporais, sendo assim caracterizadas como sistemas de tempo real embarcado. Atualmente, a computação distribuída tem alcançado este tipo de sistema e por razão principal em custos desses sistemas, alguns barramentos ou redes de comunicação vêm sendo empregados como plataforma de conexão entre módulos eletrônicos. Um exemplo de aplicação de sistemas embarcados distribuídos e de tempo real é a eletrônica embarcada em veículos automotores, onde se encontram várias unidades de controle eletrônico espalhadas interior desses veículos com diferentes funções e se comunicando via rede de comunicação. Algumas pesquisas importantes nesta área já apresentaram diferentes abordagens em sistemas distribuídos de tempo real (SDTR) objetivando cobrir a crescente demanda de desempenho, previsibilidade e confiabilidade dessas aplicações emergentes. Tais requisitos envolvem baixa latência de transmissão, baixa variabilidade no tempo (jitter), tolerância a falhas e suporte para atualizações futuras - flexibilidade. Particularmente na área automotiva, onde é considerada a possibilidade de substituição de dispositivosmecânicos/hidráulicos por sistemas eletrônicos, conhecidos como "by-wire" systems. Assegurar um comportamento previsível e confiável desses sistemas assim como agregar um nível de flexibilidade são características necessárias em grande parte de aplicações de SDTR. O modelo de comunicação FTT (Flexible Time-Triggered) apresentado nesta dissertação, apresenta um alto grau de flexibilidade em relação a outros protocolos, tais como TTCAN, TTP e FlexRay. Um sistema distribuído de tempo real baseado no modelo FTT se adapta às mudanças de requisitos da aplicação em tempo de execução, sendo possível adicionar novas unidades de controle eletrônico sobre a rede após a fase de projeto. Esta característica advém do escalonador dinâmico deste modelo de comunicação. Este trabalho apresenta algumas propostas de melhoria de desempenho de tempo de resposta do protocolo FTT-CAN, descrevendo alguns pontos negligenciados na atual especificação do protocolo. As propostas têm como foco a estratégia de disparo de mensagens e tarefas, sendo a primeira relacionada à transmissão de mensagens síncrona (ou time-triggered), onde existem dois inconvenientes que geram jitter neste segmento de transmissão; a segunda é relacionado ao disparo de tarefas, onde existem algumas deficiências na liberação de tarefas síncronas na atual especificação do protocolo FTT-CAN.Embedded computing systems have become widely used in many areas. The greater part of those systems has time constraints and therefore they can be characterized as real time embedded systems. Nowadays, distributed computing has reached the embedded application, where some fieldbuses are already being used as communication platforms. Some important researches has presented different approaches in the real time distributed embedded system domain aiming to cover the growing demands of performance, predictability and reliability of emerging applications. Such requirements involve low latency, reduced jitter, time composability, fault-tolerance and support for future extensions – flexibility. Particularly in the automotive area, on which several mechanical and/or hydraulic systems are being replaced by electronic "by-wire"systems, the importance of ensuring predictable behavior while also presenting some degree of flexibility plays a key role. Regarding to the flexibility, the Flexible Time Triggered communication model stands out against the others ones due to its high degree of flexibility. In this context, the FTT communication model appears as an interesting approach due to its high degree of flexibility while still ensuring a deterministic timing behavior. A distributed system based on a FTT communication infrastructure can adapts to changing application requirements, making possible the addition of new messages and nodes during operation. In this way, the communication infrastructure needs to schedule newest messages on-line. This master’s work presents some proposals to improve the FTT-CAN response-time and indicating some drawbacks in already presented approaches. The improvements are concerning messages and tasks scheduling. Despite of its interesting characteristics, FTT CAN present some negative aspects regarding its timing behavior: the issue is on the synchronous message transmission, where there are two neglected points that generate jitter in this traffic; the other one is tasks dispatching, where there are some deficiencies concerning synchronous tasks execution. These disadvantages were not discussed in literature yet. This work presents new proposals to task and message scheduling of FFT-CAN based applications, therefore overcoming some of the main drawbacks of the protocol.
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Nadeem, Muhammad Hassan. "Linux Kernel Module Continuous Address Space Re-Randomization." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/104685.
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Address space layout randomization (ASLR) is a technique employed to prevent exploitation of memory corruption vulnerabilities in user-space programs. While this technique is widely studied, its kernel space counterpart known as kernel address space layout randomization (KASLR) has received less attention in the research community. KASLR, as it is implemented today is limited in entropy of randomization. Specifically, the kernel image and its modules can only be randomized within a narrow 1GB range. Moreover, KASLR does not protect against memory disclosure vulnerabilities, the presence of which reduces or completely eliminates the benefits of KASLR.
In this thesis, we make two major contributions. First, we add support for position-independent kernel modules to Linux so that the modules can be placed anywhere in the 64-bit virtual address space and at any distance apart from each other. Second, we enable continuous KASLR re-randomization for Linux kernel modules by leveraging the position-independent model. Both contributions increase the entropy and reduce the chance of successful ROP attacks. Since prior art tackles only user-space programs, we also solve a number of challenges unique to the kernel code.
Our experimental evaluation shows that the overhead of position-independent code is very low. Likewise, the cost of re-randomization is also small even at very high re-randomization frequencies.Master of Science
Address space layout randomization (ASLR) is a computer security technique used to prevent attacks that exploit memory disclosure and corruption vulnerabilities. ASLR works by randomly arranging the locations of key areas of a process such as the stack, heap, shared libraries and base address of the executable in the address space. This prevents an attacker from jumping to vulnerable code in memory and thus making it hard to launch control flow hijacking and code reuse attacks. ASLR makes it impossible for the attacker to leverage return-oriented programming (ROP) by pre-computing the location of code gadgets. Unfortunately, ASLR can be defeated by using memory disclosure vulnerabilities to unravel static randomization in an attack known as Just-In-Time ROP (JIT-ROP) attack. There exist techniques that extend the idea of ASLR by continually re-randomizing the program at run-time. With re-randomization, any leaked memory location is quickly obsoleted by rapidly and continuously rearranging memory. If the period of re-randomization is kept shorter than the time it takes for an attacker to create and launch their attack, then JIT-ROP attacks can be prevented. Unfortunately, there exists no continuous re-randomization implementation for the Linux kernel. To make matters worse, the ASLR implementation for the Linux kernel (KASLR) is limited. Specifically, for x86-64 CPUs, due to architectural restrictions, the Linux kernel is loaded in a narrow 1GB region of the memory. Likewise, all the kernel modules are loaded within the 1GB range of the kernel image. Due to this relatively low entropy, the Linux kernel is vulnerable to brute-force ROP attacks. In this thesis, we make two major contributions. First, we add support for position-independent kernel modules to Linux so that the modules can be placed anywhere in the 64-bit virtual address space and at any distance apart from each other. Second, we enable continuous KASLR re-randomization for Linux kernel modules by leveraging the position-independent model. Both contributions increase the entropy and reduce the chance of successful ROP attacks. Since prior art tackles only user-space programs, we also solve a number of challenges unique to the kernel code. We demonstrate the mechanism and the generality of our proposed re-randomization technique using several different, widely used device drivers, compiled as re-randomizable modules. Our experimental evaluation shows that the overhead of position-independent code is very low. Likewise, the cost of re-randomization is also small even at very high re-randomization frequencies.
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BETTI, EMILIANO. "Satisfying hard real-time constraints using COTS components." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1310.
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L'utilizzo di componenti COTS (Commercial-Off-The-Shelf) è sempre più comune
nella produzione di sistemi embedded real-time. Prodotti commerciali, come periferiche di
Input/Output e bus di sistema, vengono utilizzati in sistemi real-time al fine
di ridurre i costi, il tempo di produzione, ed aumentare le performance.
Sfortunatamente, hardware e sistemi operativi COTS sono progettati
principalmente per ottimizzare le performance, ma con poca attenzione verso
determinismo, predicibilità ed
affidabilità. Per questa ragione, molte problematiche devono ancora essere
affrontate prima di un loro impiego in sistemi real-time ad alta criticita'.
In questa tesi abbiamo centrato la nostra attenzione su alcune delle piu' importanti
sorgenti di impredicibilita' che devono essere rimosse al fine di integrare
hardware e software COTS in sistemi hard real-time. Come prima cosa abbiamo sviluppato
ASMP-Linux, una variante di Linux che minimizza overhead e latenza del sistema
operativo. Successivamente abbiamo progettato ed implementato un nuovo sistema
di gestione dell'I/O, basato sul Real-Time Bridge, un nuovo componente
hardware che fornisce isolamento temporale sui bus COTS e rimuove le
interferenze fra periferiche di I/O. E' stato anche sviluppato un Multi-Flow
Real-Time Bridge per assicurare predicibilita' nel caso di periferiche
condivise. Infine abbiamo proposto PREM, un nuovo modello di esecuzione per
sistemi real-time che elimina le interferenze fra periferiche e CPU, e quelle
fra processi ad alta criticita' ed interruzioni hardware.
Per ognuna delle nostre soluzioni saranno descritti in dettaglio gli aspetti
teorici, l'implementazione dei prototipi ed i risultati sperimentali.Real-time embedded systems are increasingly being built using Commercial Off-The-Shelf (COTS) components such as mass-produced peripherals and buses to reduce costs, time-to-market, and increase performance. Unfortunately, COTS hardware and operating systems are typically designed to optimize average performance, instead of determinism, predictability, and reliability, hence their employment in high criticality real-time systems is still a daunting task. In this thesis, we addressed some of the most important sources of unpredictability which must be removed in order to integrate COTS hardware and software into hard real-time systems. We first developed ASMP-Linux, a variant of Linux, capable of minimizing both operating system overhead and latency. Next, we designed and implemented a new I/O management system, based on real-time bridges, a novel hardware component that provides temporal isolation on the COTS bus and removes the interference among I/O peripherals. A multi-flow real-time bridge has been also developed to address interperipheral interference, allowing predictable device sharing. Finally, we propose PREM, a new execution model for real-time systems which eliminates interference between peripherals and the CPU, as well as interference between a critical task and driver interrupts. For each of our solutions, we will describe in detail theory aspects, as well as prototype implementations and experimental measurements.
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Ratto, Matt. "The pressure of openness : the hybrid work of linux free/open source kernel developers /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3089478.
Full text
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Heursch, Arnd Christian. "Using standard operating systems for time critical applications with special emphasis on LINUX /." kostenfrei, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:706-1856.
Full text
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Hjern, Gunnar. "The modernization of a DOS-basedtime critical solar cell LBICmeasurement system." Thesis, Karlstads universitet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-74322.
Full textAbstract:
LBIC is a technique for scanning the local quantum efficiency of solar cells. This kind of measurements needs a highly specialized, and time critical controlling software. In 1996 the client, professor Markus Rinio, constructed an LBIC system, and wrote the controlling software as a Turbo-Pascal 7.0 application, running under the MS-DOS 6.22 operating system. By now (2018) both the software and several hardware components are in dire need to be modernized. This thesis thoroughly describes several important aspects of this work, and the considerations needed for a successful result. This includes both very foundational choices about the software architecture, the choice of suitable operating system, the threading model, and the adaptation to new hardware with vastly different behavior. The project also included a new hardware module for position reports and instrument triggering, as well as several adaptations to transform the DOS-based LBIC software into a pleasant modern GUI application.
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Skopal, Miroslav. "Univerzální hardwarová platforma podporující operační systém Linux." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218709.
Full textAbstract:
This thesis deals with the development problems and creating of the multi- purpose hardware platform, which supports operating system Linux. It is focused on the microprocessors using ARM architecture with architecture ARM7, ARM9 and ARM11. The scope of the first part of this thesis was searching the sales of available 32 bit ARM microprocessors. The second part is attended to a particular Mini2440 development kit, its animation and the subsequent development of the kernel drivers for OS Linux platform. One of this thesis details was also the development of my own expansive hardware module and a capacity keypad for a usage with Mini2440 developmental kit.
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Motara, Yusuf Moosa. "File integrity checking." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1007701.
Full textAbstract:
This thesis looks at file execution as an attack vector that leads to the execution of unauthorized code. File integrity checking is examined as a means of removing this attack vector, and the design, implementation, and evaluation of a best-of-breed file integrity checker for the Linux operating system is undertaken. We conclude that the resultant file integrity checker does succeed in removing file execution as an attack vector, does so at a computational cost that is negligible, and displays innovative and useful features that are not currently found in any other Linux file integrity checker.
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Kon, Fabio. "Sistemas de Arquivos Distribuídos." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/45/45132/tde-23052012-180225/.
Full textAbstract:
Este trabalho se inicia com uma discussão sobre as principais características dos Sistemas de Arquivos Distribuídos, ou seja, espaço de nomes, localização, cache, consistência, replicação, disponibilidade, escalabilidade, heterogeneidade, tolerância a falhas e segurança. Analisamos diversos sistemas de arquivos existentes quanto a estas características dando especial atenção aos sistemas NFS, Andrew, Coda, Sprite, Zebra, Harp, Frolic e Echo. Descrevemos alguns modelos analíticos para o comportamento de sistemas de arquivos distribuídos e, em seguida, apresentamos um novo modelo para sistemas baseados em leases - um mecanismo para a garantia de consistência em sistemas distribuídos. Finalmente, descrevemos a nossa implementação do sistema de arquivos distribuído SODA - que utiliza leases - apresentando dados sobre o seu desempenho.We begin with a discussion of some of the main characteristics of Distributed File Systems, namely locality, name space, cache, consistency, replication, availability, scalability, heterogeneity, fault tolerance and security. We analyze several file systems based on these characteristics. We focus mainly on NFS, Andrew, Coda, Sprite, Zebra, Harp, Frolic, and Echo. We then describe some analytical models of the behavior of distributed file systems. After that we present a new model of systems based on leases - a mechanism to assure consistency on a distributed system. Finally we describe our implementation of the SODA distributed file system - which uses leases - presenting some results on its performance.
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Tsegaye, Melekam Asrat. "A comparative study of the Linux and windows device driver architecture with a focus on IEEE1394 (high speed serial bus) drivers." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1004829.
Full textAbstract:
New hardware devices are continually being released to the public by hardware manufactures around the world. For these new devices to be usable under a PC operating system, device drivers that extend the functionality of the target operating system have to be constructed. This work examines and compares the device driver architectures currently in use by two of the most widely used operating systems, Microsoft’s Windows and Linux. The IEEE1394 (high speed serial bus) device driver stacks on each operating system are examined and compared as an example of a major device driver stack implementation, including driver requirements for the upcoming IEEE1394.1 bridging standard.
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Pazdera, Radek. "Efektivní metoda čtení adresářových položek v souborovém systému Ext4." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2013. http://www.nusl.cz/ntk/nusl-236169.
Full textAbstract:
Cílem této práce je zvýšit výkon sekvenčního procházení adresářů v souborovém systému ext4. Datová struktura HTree, jenž je v současné době použita k implementaci adresářu v ext4 zvládá velmi dobře náhodné přístupy do adresáře, avšak není optimalizována pro sekvenční procházení. Tato práce přináší analýzu tohoto problému. Nejprve studuje implementaci souborového systému ext4 a dalších subsystému Linuxového jádra, které s ním souvisí. Pro vyhodnocení výkonu současné implementace adresářového indexu byla vytvořena sada testů. Na základě výsledků těchto testů bylo navrženo řešení, které bylo následně implementováno do Linuxového jádra. V závěru této práce naleznete vyhodnocení přínosu a porovnání výkonu nové implementace s dalšími souborovými systémy v Linuxu.
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Marin, Luis Franco. "SELinux policy management framework for HIS." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/26358/1/Luis_Franco_Thesis.pdf.
Full textAbstract:
Health Information Systems (HIS) make extensive use of Information and Communication Technologies (ICT). The use of ICT aids in improving the quality and efficiency of healthcare services by making healthcare information available at the point of care (Goldstein, Groen, Ponkshe, and Wine, 2007). The increasing availability of healthcare data presents security and privacy issues which have not yet been fully addressed (Liu, Caelli, May, and Croll, 2008a). Healthcare organisations have to comply with the security and privacy requirements stated in laws, regulations and ethical standards, while managing healthcare information. Protecting the security and privacy of healthcare information is a very complex task (Liu, May, Caelli and Croll, 2008b). In order to simplify the complexity of providing security and privacy in HIS, appropriate information security services and mechanisms have to be implemented. Solutions at the application layer have already been implemented in HIS such as those existing in healthcare web services (Weaver et al., 2003). In addition, Discretionary Access Control (DAC) is the most commonly implemented access control model to restrict access to resources at the OS layer (Liu, Caelli, May, Croll and Henricksen, 2007a). Nevertheless, the combination of application security mechanisms and DAC at the OS layer has been stated to be insufficient in satisfying security requirements in computer systems (Loscocco et al., 1998). This thesis investigates the feasibility of implementing Security Enhanced Linux (SELinux) to enforce a Role-Based Access Control (RBAC) policy to help protect resources at the Operating System (OS) layer. SELinux provides Mandatory Access Control (MAC) mechanisms at the OS layer. These mechanisms can contain the damage from compromised applications and restrict access to resources according to the security policy implemented. The main contribution of this research is to provide a modern framework to implement and manage SELinux in HIS. The proposed framework introduces SELinux Profiles to restrict access permissions over the system resources to authorised users. The feasibility of using SELinux profiles in HIS was demonstrated through the creation of a prototype, which was submitted to various attack scenarios. The prototype was also subjected to testing during emergency scenarios, where changes to the security policies had to be made on the spot. Attack scenarios were based on vulnerabilities common at the application layer. SELinux demonstrated that it could effectively contain attacks at the application layer and provide adequate flexibility during emergency situations. However, even with the use of current tools, the development of SELinux policies can be very complex. Further research has to be made in order to simplify the management of SELinux policies and access permissions. In addition, SELinux related technologies, such as the Policy Management Server by Tresys Technologies, need to be researched in order to provide solutions at different layers of protection.
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Marin, Luis Franco. "SELinux policy management framework for HIS." Queensland University of Technology, 2008. http://eprints.qut.edu.au/26358/.
Full textAbstract:
Health Information Systems (HIS) make extensive use of Information and Communication Technologies (ICT). The use of ICT aids in improving the quality and efficiency of healthcare services by making healthcare information available at the point of care (Goldstein, Groen, Ponkshe, and Wine, 2007). The increasing availability of healthcare data presents security and privacy issues which have not yet been fully addressed (Liu, Caelli, May, and Croll, 2008a). Healthcare organisations have to comply with the security and privacy requirements stated in laws, regulations and ethical standards, while managing healthcare information. Protecting the security and privacy of healthcare information is a very complex task (Liu, May, Caelli and Croll, 2008b). In order to simplify the complexity of providing security and privacy in HIS, appropriate information security services and mechanisms have to be implemented. Solutions at the application layer have already been implemented in HIS such as those existing in healthcare web services (Weaver et al., 2003). In addition, Discretionary Access Control (DAC) is the most commonly implemented access control model to restrict access to resources at the OS layer (Liu, Caelli, May, Croll and Henricksen, 2007a). Nevertheless, the combination of application security mechanisms and DAC at the OS layer has been stated to be insufficient in satisfying security requirements in computer systems (Loscocco et al., 1998). This thesis investigates the feasibility of implementing Security Enhanced Linux (SELinux) to enforce a Role-Based Access Control (RBAC) policy to help protect resources at the Operating System (OS) layer. SELinux provides Mandatory Access Control (MAC) mechanisms at the OS layer. These mechanisms can contain the damage from compromised applications and restrict access to resources according to the security policy implemented. The main contribution of this research is to provide a modern framework to implement and manage SELinux in HIS. The proposed framework introduces SELinux Profiles to restrict access permissions over the system resources to authorised users. The feasibility of using SELinux profiles in HIS was demonstrated through the creation of a prototype, which was submitted to various attack scenarios. The prototype was also subjected to testing during emergency scenarios, where changes to the security policies had to be made on the spot. Attack scenarios were based on vulnerabilities common at the application layer. SELinux demonstrated that it could effectively contain attacks at the application layer and provide adequate flexibility during emergency situations. However, even with the use of current tools, the development of SELinux policies can be very complex. Further research has to be made in order to simplify the management of SELinux policies and access permissions. In addition, SELinux related technologies, such as the Policy Management Server by Tresys Technologies, need to be researched in order to provide solutions at different layers of protection.
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Jones, Robert M. "Content Aware Request Distribution for High Performance Web Service: A Performance Study." PDXScholar, 2002. https://pdxscholar.library.pdx.edu/open_access_etds/2662.
Full textAbstract:
The World Wide Web is becoming a basic infrastructure for a variety of services, and the increases in audience size and client network bandwidth create service demands that are outpacing server capacity. Web clusters are one solution to this need for highperformance, highly available web server systems. We are interested in load distribution techniques, specifically Layer-7 algorithms that are content-aware. Layer- 7 algorithms allow distribution control based on the specific content requested, which is advantageous for a system that offers highly heterogenous services. We examine the performance of the Client Aware Policy (CAP) on a Linux/Apache web cluster consisting of a single web switch that directs requests to a pool of dual-processor SMP nodes. We show that the performance advantage of CAP over simple algorithms such as random and round-robin is as high as 29% on our testbed consisting of a mixture of static and dynamic content. Under heavily loaded conditions however, the performance decreases to the level of random distribution. In studying SMP vs. uniprocessor performance using the same number of processors with CAP distribution, we find that SMP dual-processor nodes under moderate workload levels provide equivalent throughput as the same number of CPU’s in a uniprocessor cluster. As workload increases to a heavily loaded state however, the SMP cluster shows reduced throughput compared to a cluster using uniprocessor nodes. We show that the web cluster’s maximum throughput increases linearly with the addition of more nodes to the server pool. We conclude that CAP is advantageous over random or round-robin distribution under certain conditions for highly dynamic workloads, and suggest some future enhancements that may improve its performance.
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Bissyandé, Tegawendé F. "Contributions à l'Amélioration du Débogage des Services Noyau dans un Système d'Exploitation Monolithique." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00808877.
Full textAbstract:
Alors que la recherche sur la qualité du code des systèmes a connu un formidable engouement, les systèmes d'exploitation sont encore aux prises avec des problèmes de fiabilité notamment dûs aux bogues de programmation au niveau des services noyaux tels que les pilotes de périphériques et l'implémentation des systèmes de fichiers. Des études ont en effet montré que que chaque version du noyau Linux contient entre 600 et 700 fautes, et que la propension des pilotes de périphériques à contenir des erreurs est jusqu'à sept fois plus élevée que toute autre partie du noyau. Ces chiffres suggèrent que le code des services noyau n'est pas suffisamment testé et que de nombreux défauts passent inaperçus ou sont difficiles à réparer par des programmeurs non-experts, ces derniers formant pourtant la majorité des développeurs de services. Cette thèse propose une nouvelle approche pour le débogage et le test des services noyau. Notre approche est focalisée sur l'interaction entre les services noyau et le noyau central en abordant la question des "trous de sûreté" dans le code de définition des fonctions de l'API du noyau. Dans le contexte du noyau Linux, nous avons mis en place une approche automatique, dénommée Diagnosys, qui repose sur l'analyse statique du code du noyau afin d'identifier, classer et exposer les différents trous de sûreté de l'API qui pourraient donner lieu à des fautes d'exécution lorsque les fonctions sont utilisées dans du code de service écrit par des développeurs ayant une connaissance limitée des subtilités du noyau. Pour illustrer notre approche, nous avons implémenté Diagnosys pour la version 2.6.32 du noyau Linux. Nous avons montré ses avantages à soutenir les développeurs dans leurs activités de tests et de débogage.
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Barbalace, Antonio. "Emerging Hardware Architectures and Advanced Open-Source Software Technologies for Real-Time Control and Data Acquisition in Quasi-Continuous Nuclear Fusion Experiments." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3421603.
Full textAbstract:
Research in nuclear fusion devices is motivated by the increasing global demand of low-cost and eco-friendly energy. To meet the requirements for an economically attractive fusion power plant, new real-time control and data acquisition systems that support quasi-continuous plasma operation and unstable plasma scenarios have to be investigated.
This thesis covers hardware and software design and codesign issues in real-time control and data acquisition for quasi-continuous nuclear experiments, with emphasis on the choice of data acquisition and generation hardware, central processing units, real-time operating systems and
application frameworks.
The work starts with an introduction to fusion science and magnetic nuclear fusion experimental devices. Two different experiments (RFX-mod and JET) are then presented in order to show several plasma instabilities that need to be controlled in real time, namely Magneto Hydro Dynamic modes stabilization (MHD) and Vertical Stabilization (VS).
The thesis then focuses on the hardware design of data acquisition boards; moreover interpolation problems in analog to digital signal conversion that arise from the adoption of nonsimultaneous sampling instead of the established simultaneous sampling are covered.
A section dedicated to Open-Source software that addresses Operating Systems and application frameworks for low latency real-time control and data acquisition follows. Linux with its Real-Time patches is proved to be a Hard Real-Time Operating System running on multicore CPUs along with resource partitioning and shielding.
Different control computational models and software frameworks implementing them are presented; MARTe, among EPICS and many others, has shown the lowest latency and the most bounded jitter.
The thesis ends with the design and implementation details of the proposal for the RFX-mod MHD control system upgrade.La ricerca sulla fusione nucleare oggigiorno é fortemente motivata dal continuo aumento della richiesta globale di energia a basso costo ed ecocompatibile. Per poter soddisfare i requisiti per la costruzione di impianti da fusione commerciali devono essere studiati nuovi sistemi per il controllo in tempo reale e l'acquisizione dati, che supportano esperimenti con plasma quasi-continui e scenari di plasmi non stabili. Questa tesi tratta delle soluzioni hardware e software per il controllo in tempo reale e l'acquisizione dati negli esperimenti fusionistici operanti in modalitá quasi continua. La tesi presenta un'indagine sulle schede per l'acquisizione e la generazione dati, sulla scelta dell'elaboratore, sui sistemi operativi in tempo reale e sui framework applicativi. Il lavoro incomincia con un'introduzione teorica sulla fusione termonucleare e alcuni dispositivi esperimentali per la fusione. In particolare due diversi esperimenti (RFX-mod e JET) vengono presentati per identificare diverse instabilitá presenti nel plasma che devono essere controllate in tempo reale, queste sono la stabilizzazione dei modi Magneto-Hydro dinamici (MHD) e la stabilizzazione verticale (VS). Segue una parte dedicata all'analisi delle diverse architetture di acquisizione dati realizzati in dispositivi commerciali. Quindi viene discusso come riallineare digitalmente, tramite interpolazione o filtri passa-tutto, dei segnali analogici acquisiti con campionamento non simultaneo utilizzando schede con diversi ingressi multiplexati su un unico convertitore. Vi é quindi una sezione dedicata al software libero dedicata in particolare ai sistemi operativi e ai framework applicativi con provata bassa latenza utilizzabili per il controllo in tempo reale e l'acqusizione dati. Linux, corredato delle sue real-time patches, dimostrata di essere un sistema operativo deterministico (real-time) se opportunamente configurato su sistemi multiprocessore utilizzando le tecniche di partizionamento e schermatura delle risorse. Diversi modelli computazionali e alcuni framework applicativi che li implementano vengono analizzati. MARTe tra EPICS e altri software per il controllo presenta la latenza piú bassa e il jitter piú contenuto. La tesi si conclude con il progetto di aggiornamento del sistema di controllo dei modi MHD dell'esperimento RFX-mod.