Thèses sur le sujet « Isolation de l'accès à la mémoire »
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Yang, Ye. « Isolation Mechanisms within the vSwitch of Cloud Computing Platform ». Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS191.
Texte intégralAs an important component of cloud platform, virtual switch (vSwitch) is responsible for achieving network connectivity between virtual machines (VMs) and external devices. Most existing vSwitches adopt the split design principle, which destroys the isolation between VMs. In vSwitch, different VMs compete for shared resources and unrestricted memory access, making them unable to guarantee stable network quality of service (QoS), while facing the risk of data plane attacks and illegal access to memory. In order to solve these performance, failure and security problems caused by the lack of isolation, the main works and contributions of this thesis are as follows: 1) Network QoS method based on CPU cycle isolation (C2QoS). This approach secures VM network bandwidth by isolating concurrency from CPU resources, and at the same time reduces additional VM network latency caused by concurrency by 80%. 2) Data plane attack defense mechanism based on stream table isolation (D-TSE). D-TSE uses VM as the unit to separate the flow table structure to achieve independent packet classification performance and fault isolation at the cost of 5% additional CPU usage. 3) Virtualized Network I/O (VNIO) mechanism based on Memory Access Isolation (S2H). Based on a secure memory sharing model, S2H provides VM memory isolation and security at the cost of 2-9% increased latency
Charrier, Gilda. « Mémoire et identité : le souvenir de l'accès à la profession comme expression de l'identité pour soi ». Paris 5, 1993. http://www.theses.fr/1993PA05H012.
Texte intégralOur research gets place in sociology of memory. This study integrates the definition of the individual memory in its social conditions of composition and as the point of view of a person. We consider the production of memory in professional access as expression of identity for oneself. The individual actualizes his memory by forming his point of view according to his self-definition. He confirms, denies or changes the idea of his self by means of his profession. We make a distinction between identity for oneself and identity for others. An examination by interview allowed us to frame three ways to express the point of view of the individual on himself together with the relation to his job. There is no possibility to analyze the collected speeches in terms of retrospective memory or prospective memory. Our informants maintain trough acts developing on the same theme, or through speeches constructed around the same oppositions, an identity with oneself. The memory produced in this way in an introspective one. According to the relation to profession, introspective memory is one of action, of potentiality, or of indefiniteness
Dang, Alexandre. « Compilation sécurisée pour la protection de la mémoire ». Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S111.
Texte intégralOur society has been growingly dependent on computer systems and this tendency will not slow down in the incoming years. Similarly, interests over cybersecurity have been increasing alongside the possible consequences brought by successful attacks on these systems. This thesis tackles the issue of security of systems and especially focuses on compilation to achieve its goal. Compilation is the process of translating source programs written by humans to machine code readable by our systems. We explore the two possible behaviours of a secure compiler which are enforcement and preservation. First, we have developed CompCertSFI, a compiler which enforces the isolation of modules into closed memory areas called sandboxes. These modules are then unable to access memory regions outside of their sandbox which prevents any malicious module from corrupting other entities of the system. On the topic of security preservation, we defined a notion of Information Flow Preserving transformation to make sure that a program does get less secure during compilation. Our property is designed to preserve security against side-channel attacks. This new category of attacks uses physical mediums such as time or power consumption which are taken into account by current compilers
Hassan, Khaldon. « Architecture De Contrôleur Mémoire Configurable et Continuité de Service Pour l'Accès à la Mémoire Externe Dans Les Systèmes Multiprocesseurs Intégrés à Base de Réseaux Sur Puce ». Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00656470.
Texte intégralKhaldon, Hassan. « Architecture de contrôleur mémoire configurable et continuité de service pour l'accès à la mémoire externe dans les systèmes multiprocesseurs intégrés à base de réseaux sur puce ». Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT051/document.
Texte intégralThe ongoing advancements in VLSI technology allow System-on-Chip (SoC) to integrate many heterogeneous functions into a single chip, but still demand, because of economical constraints, a single and shared main off-chip SDRAM. Consequently, main memory system design, and more specifically the architecture of the memory controller, has become an increasingly important factor in determining the overall system performance. Choosing a memory controller design that meets the needs of the whole system is a complex issue. This requires the exploration of the memory controller architecture, and then the validation of each configuration by simulation. Although the architecture exploration of the memory controller is a key to successful system design, state of the art memory controllers are not as flexible as necessary for this task. Even if some of them present a configurable architecture, the exploration is restricted to limited sets of parameters such as queue depth, data bus size, quality-of-service level, and bandwidth distribution. Several classes of traffic co-exist in real applications, e.g. best effort traffic and guaranteed service traffic, and access the main memory. Therefore, considering the interaction between the memory subsystem and the interconnection system has become vital in today's SoCs. Many on chip networks provide guaranteed services to traffic classes to satisfy the applications requirements. However, very few studies consider the SDRAM access within a system approach, and take into account the specificity of the SDRAM access as a target in NoC-based SoCs. This thesis addresses the topic of dynamic access to SDRAM in NoC-based SoCs. We introduce a totally customizable memory controller architecture based on fully configurable building components and design a high level cycle approximate model for it. This enables the exploration of the memory subsystem thanks to the ease of configuration of the memory controller architecture. Because of the discontinuity of services between the network and the memory controller, we also propose within the framework of this thesis an Extreme End to End flow control protocol to access the memory device through a multi-port memory controller. The simple yet novel idea is to exploit information about the memory controller status in the NoC. Experimental results show that by controlling the best effort traffic injection in the NoC, our protocol increases the performance of the guaranteed service traffic in terms of bandwidth and latency, while maintaining the average bandwidth of the best effort traffic
Reuther, Nina Mildred. « La Mémoire chantée des Secwepemc : transmission orale des savoirs et gestion de l'accès aux ressources chez les "Shuswap" (Colombie britannique/Canada) ». Université Marc Bloch (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/restreint/theses_doctorat/2007/REUTHER_Nina_Mildred_2007.pdf.
Texte intégralCette thèse cherche à définir la fonction du chant dans un système nord-amérindien de transmission orale des savoirs, et cela à l’exemple des Shuswap, qui attribuent une grande importance à leur « propriété intellectuelle ». La thèse est divisée en 4 sections. Section 1 comporte une introduction ethnographique générale au travail (l’ »aire culturelle » du Plateau et son histoire, ensuite les Secwepemc plus précisément) et présente le concept de la thèse, fondée sur une méthode de travail combinant une longue recherche sur le terrain et l’étude des sources écrites. Section 2 confronte les études éthno-musicologiques existantes sur le Plateau avec la manière secwepemc. Section 3 présente quelques aspects de la manière secwepemc de concevoir le « monde intégral », ainsi que les trois systèmes de classification du répertoire (utilisation, origine, droits d’accès). Section 4 comporte l’analyse de la place du chant face à d’autres voies de transmission orale (cérémonies, rituels, mythes et histoires), et la tentative d’approcher de manière holistique cette culture à partir de sa conception du chant
Clément, Charles. « Isolation des extensions de systèmes d'exploitation dans une machine virtuelle ». Paris 6, 2009. http://www.theses.fr/2009PA066624.
Texte intégralVagnot, Caroline. « Efficacité d'une activité discriminante : quand isolation et action participent à l'émergence d'un jugement de reconnaissance ». Thesis, Montpellier 3, 2014. http://www.theses.fr/2014MON30054/document.
Texte intégralThis thesis is part of a vision where memory is considered as a unique system maintaining all of our experiences in multidimensional memory traces, that is to say, reflecting sensorimotor properties from our past experiences. Moreover, from this perspective, knowledge is not retrieved in memory (i.e. memory content), but emerges from the interaction between the current situation and traces of past situations (i.e. memory processes). This emerging knowledge is the product of the dynamics of activation and integration mechanisms (Act-In Model, Versace et al, 2014). Our objective was to investigate the influence of these dynamics on the effectiveness of discriminant activity, that is to say, our ability to distinguish one specific knowledge from other ones (e.g. recall, recognition). We then conducted two sets of experiments to show that this efficiency depends on both the characteristics of the memory trace (i.e. trace distinctiveness) and those of the situation (i.e. similarity between the retrieval cues and memory traces). Primarily, we chose to manipulate the trace distinctiveness through an isolation paradigm. Secondly we focused on motor similarity between the retrieval situation and traces of past experiences. The difficulty to observe significant differences (first serie of experiments) and the originality of some results (second serie of experiments) tend to support the idea of a memory allowing the construction of behavior in response to a given situation
Millon, Etienne. « Analyse de sécurité de logiciels système par typage statique ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01067475.
Texte intégralJomaa, Narjes. « Le co-design d’un noyau de système d’exploitation et de sa preuve formelle d’isolation ». Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1I075/document.
Texte intégralIn this thesis we propose a new kernel concept adapted to verification that we have called protokernel. It is a minimal operating system kernel where the minimization of its size is motivated by the reduction of the cost of proof and of the attack surface. This leads us to define a new strategy of codesign of the kernel and its proof. It is based mainly on the feedbacks between the various steps of development of the kernel, ranging from the definition of its specification to the formal verification of its properties. Thus, in this context we have designed and implemented the Pip protokernel. All of its system calls were carefully identified during the design step to ensure both the feasibility of proof and the usability of the system. The code of Pip is written in Gallina (the specification language of the Coq proof assistant) and then automatically translated into C code. The main property studied in this work is a security property, expressed in terms of memory isolation. This property has been largely discussed in the literature due to its importance. Thus, our work consists more particularly in guiding the developer to define the fundamental concepts of this minimalistic kernel through the formal verification of its isolation property. The verification strategy was first experimented with a generic microkernel model that we also wrote in Gallina. With this simplified microkernel model we were able to validate our verification approach before applying it to the concrete implementation of the Pip protokernel
Andronick, Liège June. « Modélisation et vérification formelles de systèmes embarqués dans les cartes à microprocesseur : plate-forme Java Card et système d'exploitation ». Paris 11, 2006. http://www.theses.fr/2006PA112085.
Texte intégralThe work presented in this thesis aims at strengthening the security and safety level of smart card embedded systems, with the use of Formal Methods. On one hand, we present the formal verification of the isolation of the data belonging to different applets loaded on the same card. More precisely, we describe the formal proof, in the Coq proof system, that the run-time access control, performed by the Java Card platform, ensures data confidentiality and integrity. On the other hand, we study the correctness and the safety of low level source code of an embedded operating system. Such source code is illustrated by a case study of a Flash memory management module, using a journalling mechanism and ensuring the memory consistency in the case of a card tear. The verification of functional and local properties has been developed using the Caduceus program verification tool. Since this tool does not support some low level constructions of the C language, such as the unions and the casts, we propose an analysis and some solutions for the formalisation of such constructions. We also propose an extension of Caduceus that allows to specify and verify the behaviour of a function in the case of sudden interruption of its execution. Then, we introduce a methodology for the verification of high level and global properties, which is meant for the expression and proof of this kind of properties on a model formally linked to the source code. More precisely, we describe an automatic extraction of a transition system from the annotations that are verified by the source code. This transition system can then be translated in a high order logic
Bergougnoux, Quentin. « Co-design et implémentation d’un noyau minimal orienté par sa preuve, et évolution vers les architectures multi-coeur ». Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I029/document.
Texte intégralDue to the major growth of the Internet of Things and Cloud Computing worlds, security in those systems has become a major issue. Many exploits and attacks happened in the last few years, highlighting the need of strong security guarantees on those systems. Most of the times, a vulnerability in the kernel or one of its modules is enough to compromise the whole system. Etablishing and proving security properties through proof assistants seems to be a huge step towards bringing security guarantees. This relies on using mathematical models in order to reason on their behaviour, and prove the latter remains correct. Still, due to the huge and complex code base of the software running on those systems, especially the kernel, this is a tedious task. Understanding the internals of those kernels, and writing an associated proof on some security property, is more and more difficult as the kernel grows in size. In this thesis, I propose a new approach of kernel design, the proto-kernel. By reducing the features provided by the kernel to their most minimal subset, this model, in addition to lowering the attack surface, reduces the cost of the proof effort. It also allows a wide range of systems to be built on top of it, as the minimality of the features embedded into the kernel causes the remaining features to be built at the userland level. I also provide in this thesis a concrete implementation of this model, the Pip proto-kernel. By providing only the most minimal and mandatory system calls, both the usability of the kernel and the feasibility of the proof are ensured. In order to reduce the model-to-binary transition effort, most of the kernel is written directly in Gallina, the language of the Coq Proof Assistant, and is automatically converted to compilable C code during compilation phase. Pip only relies on a thin hardware abstraction layer written in low-level languages, which provides the operations the model requires, such as modifying the hardware configuration. Moreover, as Internet of Things and Cloud Computing use cases would require, I propose some extensions of Pip’s model, in order to support multicore hardware. Backed up by real implementations, those models bring the Pip proto-kernel to multicore architectures, bringing strong security guarantees in those modern environments. Finally, I validate my approach and its implementation through benchmarks and a Linux kernel port proof-of-concept, displaying the flexibility of the Pip proto-kernel in real world environments
Laniel, Francis. « MemOpLight : vers une consolidation mémoire pour les conteneurs grâce à un retour applicatif ». Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS372.
Texte intégralNowadays, deploying and executing applications in the cloud is a reality. The cloud can not exist without virtualization. This concept consists of slicing physical machines into several sub-machines, isolated from one another, known as virtual machines. Recently, containers emerged as a viable alternative to virtual machines. Containers are lighter than virtual machines and bring the same isolation and security guarantees. Nonetheless, the isolation they offer is maybe too important. Indeed, existing mechanisms enforce memory isolation by ensuring that no container starves the others; however, they do not adapt to changes in workload. Thus, it is impossible to consolidate memory, i.e. to reclaim memory unused by some containers to make a better use of it. To answer this problem and ensure both isolation and consolidation, we introduce MemOpLight. This mechanism adapts to workload changes thanks to application feedback. Each container tells the kernel whether it has good or bad performance to guide memory reclaim. Memory is first reclaimed from containers with good performance in the hope that the others can improve their own performance. The idea is to find a balance where all containers have satisfying performance. MemOpLight increases container satisfactions by 13% compared to existing mechanisms
Brevet, Gentil Julie. « Influence des facteurs socio-économiques et géographiques sur l'incidence, l'accès aux soins et la survie des femmes atteintes d'un cancer du sein ». Thesis, Dijon, 2012. http://www.theses.fr/2012DIJOMU04/document.
Texte intégralIn developed countries, breast cancer is currently the leading cancer in women in terms of incidence and mortality (standardized rate of 101.5 and 17.7 per 100,000 person-years in 2005, respectively). Many risk factors and prognostic factors have been studied and are well known. Research is under way with regard to every step in the development of breast cancer, but the impact of socio-economic and geographic factors, at the individual and environmental level with regard to the disease have never been studied in France.The general aim of this work was to explore the impact of these factors in different ways to build on our knowledge and to develop practical applications in the primary, secondary or tertiary prevention of breast cancer.In our first study, we showed that women with a low socio-educational level were less likely to have benefited from at least one mammography within the 6 years or at least one gynaecological consultation within the 3 years before the diagnosis of breast cancer. These women also had a more advanced tumour at diagnosis than did women with a higher socio-educational level. These variables also came to light as predictors of a poor prognosis in terms of survival. In our second study, we showed that access to a surgeon specialised in breast cancer surgery, which is associated with better survival, was influenced by the socio-economic level of the patient’s place of residence, as well as the distance between the patient’s home and reference centres for cancer treatment, where the specialised surgeons work. In our third study, we showed that in contrast to many cancers, the incidence of breast cancer was highest in the most socio-economically privileged areas, and this whatever the age of the patient. We have no explanation for this phenomenon, particularly with regard to the youngest age group of women. Finally, the aim of our fourth study, which is currently on-going, is to study at the individual level, using the new European deprivation index adapted to France, to what extent economic wealth and social standing, as well as the proximity of medical services for patients with breast cancer have an impact on tumour stage, access to treatment, treatment techniques and survival
Carver, Damien. « Advanced consolidation for dynamic containers ». Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS513.
Texte intégralThe virtualization of computing resources has given rise to cloud computing. More recently, container-based lightweight virtualization has become increasingly popular. Containers offer performance isolation comparable to that of virtual machines, but promise better resource consolidation due to their flexibility. In this thesis we highlight performance isolation losses assumed to be guaranteed to an active container. These losses occur during consolidation, i.e. when the unused memory of an inactive container is transferred to a new container that starts. However, in a non-virtualized environment, this memory consolidation scenario does not result in a drop in performance among the most active processes. We therefore propose, as a first step, to measure the memory activity of containers using state-of-the-art metrics. Then, to ensure the isolation of the most active containers during memory consolidations, we modify the behavior of the Linux kernel in order to reclaim the memory of the containers defined as being the most inactive by the metric. In a second step, we propose another method for estimating the memory activity of containers based on a global clock of memory events. This method is more reactive than the previous one because it seeks to protect containers with the most recent memory activity
Millon, Etienne. « Analyse de sécurité de logiciels système par typage statique ». Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066120.
Texte intégralOperating system kernels need to manipulate data that comes from user programs through system calls. If it is done in an incautious manner, a security vulnerability known as the Confused Deputy Problem can lead to information disclosure or privilege escalation. The goal of this thesis is to use static typing to detect the dangerous uses of pointers that are controlled by userspace. Most operating systems are written in the C language. We start by isolating Safespeak, a safe subset of it. Its operational semantics as well as a type system are described, and the classic properties of type safety are established. Memory states are manipulated using bidirectional lenses, which can encode partial updates to states and variables. A first analysis is described, that identifies integers used as bitmasks, which are a common source of bugs in C programs. Then, we add to Safespeak the notion of pointers coming from userspace. This breaks type safety, but it is possible to get it back by assigning a different type to the pointers that are controlled by userspace. This distinction forces their dereferencing to be done in a controlled fashion. This technique makes it possible to detect two bugs in the Linux kernel: the first one is in a video driver for an AMD video card, and the second one in the ptrace system call for the Blackfin architecture
Paté, Noémie. « L'accès - ou le non-accès - à la protection des mineur.e.s isolé.e.s en situation de migration : l'évaluation de la minorité et de l'isolement ou la mise à l'épreuve de la crédibilité narrative, comportementale et physique des mineur.e.s isolé.e.s ». Thesis, Paris 10, 2018. http://www.theses.fr/2018PA100154.
Texte intégralThis research seeks to understand how unaccompanied migrant children, that have arrived on French territory without a legal guardian can access child protective services. Arrived on the stage of the assessment of age and isolation, these young migrants’ narrative, behavioral and physical credibility is tested. Through their narratives, physical and non-verbal expressions, these children must demonstrate to those who judge them that they are a “child”, at all costs. Consequently, several questions can be asked: How can age be judged? How are the decisions of classification between the "true" and "fake" minors taken? How are child protection actors brought to mobilize arguments, criteria and justifications which lead to practices of "migratory management "? To study the practices of judgment in this context of uncertainty, meaning the assessment of age and isolation, this dissertation offers an analysis of the internal workings of institutions. The field investigation was carried out between October 2014 and November 2016, firstly in a centre of evaluation of age and isolation managed by the association France terre d’asile in Paris region, then with the various actors in charge of “distributing" the protection in various Parisian departments, and finally in two urban camps that are self-managed by migrants. Based on this investigation and through the study of everyday life of the institution, this dissertation questions the way unaccompanied children are judged, labelled and selected before having access - or not - to child protection