Composing Abstractions Using the Null-Kernel
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Application Performance and Flexibility on Exokernel Systems
Application Performance and Flexibility On Exokernel Systems –M. F. Kaashoek, D.R. Engler, G.R. Ganger et. al. Presented by Henry Monti Exokernel ● What is an Exokernel? ● What are its advantages? ● What are its disadvantages? ● Performance ● Conclusions 2 The Problem ● Traditional operating systems provide both protection and resource management ● Will protect processes address space, and manages the systems virtual memory ● Provides abstractions such as processes, files, pipes, sockets,etc ● Problems with this? 3 Exokernel's Solution ● The problem is that OS designers must try and accommodate every possible use of abstractions, and choose general solutions for resource management ● This causes the performance of applications to suffer, since they are restricted to general abstractions, interfaces, and management ● Research has shown that more application control of resources yields better performance 4 (Separation vs. Protection) ● An exokernel solves these problems by separating protection from management ● Creates idea of LibOS, which is like a virtual machine with out isolation ● Moves abstractions (processes, files, virtual memory, filesystems), to the user space inside of LibOSes ● Provides a low level interface as close to the hardware as possible 5 General Design Principles ● Exposes as much as possible of the hardware, most of the time using hardware names, allowing libOSes access to things like individual data blocks ● Provides methods to securely bind to resources, revoke resources, and an abort protocol that the kernel itself -
The Flask Security Architecture: System Support for Diverse Security Policies
The Flask Security Architecture: System Support for Diverse Security Policies Ray Spencer Secure Computing Corporation Stephen Smalley, Peter Loscocco National Security Agency Mike Hibler, David Andersen, Jay Lepreau University of Utah http://www.cs.utah.edu/flux/flask/ Abstract and even many types of policies [1, 43, 48]. To be gen- erally acceptable, any computer security solution must Operating systems must be flexible in their support be flexible enough to support this wide range of security for security policies, providing sufficient mechanisms for policies. Even in the distributed environments of today, supporting the wide variety of real-world security poli- this policy flexibility must be supported by the security cies. Such flexibility requires controlling the propaga- mechanisms of the operating system [32]. tion of access rights, enforcing fine-grained access rights and supporting the revocation of previously granted ac- Supporting policy flexibility in the operating system is cess rights. Previous systems are lacking in at least one a hard problem that goes beyond just supporting multi- of these areas. In this paper we present an operating ple policies. The system must be capable of supporting system security architecture that solves these problems. fine-grained access controls on low-level objects used to Control over propagation is provided by ensuring that perform higher-level functions controlled by the secu- the security policy is consulted for every security deci- rity policy. Additionally, the system must ensure that sion. This control is achieved without significant perfor- the propagation of access rights is in accordance with mance degradation through the use of a security decision the security policy. -
CS 414/415 Systems Programming and Operating Systems
1 MODERN SYSTEMS: EXTENSIBLE KERNELS AND CONTAINERS CS6410 Hakim Weatherspoon Motivation 2 Monolithic Kernels just aren't good enough? Conventional virtual memory isn't what userspace programs need (Appel + Li '91) Application-level control of caching gives 45% speedup (Cao et al '94) Application-specific VM increases performance (Krueger '93, Harty + Cheriton '92) Filesystems for databases (Stonebraker '81) And more... Motivation 3 Lots of problems… Motivation 4 Lots of problems…Lots of design opportunities! Motivation 5 Extensibility Security Performance Can we have all 3 in a single OS? From Stefan Savage’s SOSP 95 presentation Context for these papers 1990’s Researchers (mostly) were doing special purpose OS hacks Commercial market complaining that OS imposed big overheads on them OS research community began to ask what the best way to facilitate customization might be. In the spirit of the Flux OS toolkit… 2010’s containers: single-purpose appliances Unikernels: (“sealable”) single-address space Compile time specialized Motivation 7 1988-1995: lots of innovation in OS development Mach 3, the first “true” microkernel SPIN, Exokernel, Nemesis, Scout, SPACE, Chorus, Vino, Amoeba, etc... And even more design papers Motivation 8 Exploring new spaces Distributed computing Secure computing Extensible kernels (exokernel, unikernel) Virtual machines (exokernel) New languages (spin) New memory management (exokernel, unikernel) Exokernel Dawson R. Engler, M. Frans Kaashoek and James O’Toole Jr. Engler’s Master’s -
Microkernels Meet Recursive Virtual Machines
Microkernels Meet Recursive Virtual Machines Bryan Ford Mike Hibler Jay Lepreau Patrick Tullmann Godmar Back Stephen Clawson Department of Computer Science, University of Utah Salt Lake City, UT 84112 [email protected] http://www.cs.utah.edu/projects/flux/ Abstract ªverticallyº by implementing OS functionalityin stackable virtual machine monitors, each of which exports a virtual Thispaper describes a novel approach to providingmod- machine interface compatible with the machine interface ular and extensible operating system functionality and en- on which it runs. Traditionally,virtual machines have been capsulated environments based on a synthesis of micro- implemented on and export existing hardware architectures kernel and virtual machine concepts. We have developed so they can support ªnaiveº operating systems (see Fig- a software-based virtualizable architecture called Fluke ure 1). For example, the most well-known virtual machine that allows recursive virtual machines (virtual machines system, VM/370 [28, 29], provides virtual memory and se- running on other virtual machines) to be implemented ef- curity between multiple concurrent virtual machines, all ®ciently by a microkernel running on generic hardware. exporting the IBM S/370 hardware architecture. Further- A complete virtual machine interface is provided at each more, special virtualizable hardware architectures [22, 35] level; ef®ciency derives from needing to implement only have been proposed, whose design goal is to allow virtual new functionality at each level. This infrastructure allows machines to be stacked much more ef®ciently. common OS functionality, such as process management, demand paging, fault tolerance, and debugging support, to This paper presents a new approach to OS extensibil- be provided by cleanly modularized, independent, stack- ity which combines both microkernel and virtual machine able virtual machine monitors, implemented as user pro- concepts in one system. -
All Computer Applications Need to Store and Retrieve Information
MyFS: An Enhanced File System for MINIX A Dissertation Submitted in partial fulfillment of the requirement for the award of the degree of MASTER OF ENGINEERING ( COMPUTER TECHNOLOGY & APPLICATIONS ) By ASHISH BHAWSAR College Roll No. 05/CTA/03 Delhi University Roll No. 3005 Under the guidance of Prof. Asok De Department Of Computer Engineering Delhi College Of Engineering, New Delhi-110042 (University of Delhi) July-2005 1 CERTIFICATE This is to certify that the dissertation entitled “MyFS: An Enhanced File System for MINIX” submitted by Ashish Bhawsar in the partial fulfillment of the requirement for the award of degree of Master of Engineering in Computer Technology and Application, Delhi College of Engineering is an account of his work carried out under my guidance and supervision. Professor D. Roy Choudhury Professor Asok De Head of Department Head of Department Department of Computer Engineering Department of Information Technology Delhi College of Engineering Delhi College of Engineering Delhi Delhi 2 ACKNOWLEDGEMENT It is a great pleasure to have the opportunity to extent my heartiest felt gratitude to everybody who helped me throughout the course of this project. I would like to express my heartiest felt regards to Dr. Asok De, Head of the Department, Department of Information Technology for the constant motivation and support during the duration of this project. It is my privilege and owner to have worked under the supervision. His invaluable guidance and helpful discussions in every stage of this thesis really helped me in materializing this project. It is indeed difficult to put his contribution in few words. I would also like to take this opportunity to present my most sincere regards to Dr. -
Protection in the Think Exokernel Christophe Rippert, Jean-Bernard Stefani
Protection in the Think exokernel Christophe Rippert, Jean-Bernard Stefani To cite this version: Christophe Rippert, Jean-Bernard Stefani. Protection in the Think exokernel. 4th CaberNet European Research Seminar on Advances in Distributed Systems, May 2001, Bertinoro, Italy. hal-00308882 HAL Id: hal-00308882 https://hal.archives-ouvertes.fr/hal-00308882 Submitted on 4 Aug 2008 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Protection in the Think exokernel Christophe Rippert,∗ Jean-Bernard Stefani† [email protected], [email protected] Introduction In this paper, we present our preliminary ideas concerning the adaptation of security and protection techniques in the Think exokernel. Think is our proposition of a distributed adaptable kernel, designed according to the exokernel architecture. After summing up the main motivations for using the exokernel architecture, we describe the Think exokernel as it has been implemented on a PowerPC machine. We then present the major protection and security techniques that we plan to adapt to the Think environment, and give an example of how some of these techniques can be combined with the Think model to provide fair and protected resource management. -
OS Extensibility: Spin, Exo-Kernel and L4
OS Extensibility: Spin, Exo-kernel and L4 Extensibility Problem: How? Add code to OS how to preserve isolation? … without killing performance? What abstractions? General principle: mechanisms in OS, policies through the extensions What mechanisms to expose? 2 Spin Approach to extensibility Co-location of kernel and extension Avoid border crossings But what about protection? Language/compiler forced protection Strongly typed language Protection by compiler and run-time Cannot cheat using pointers Logical protection domains No longer rely on hardware address spaces to enforce protection – no boarder crossings Dynamic call binding for extensibility 3 ExoKernel 4 Motivation for Exokernels Traditional centralized resource management cannot be specialized, extended or replaced Privileged software must be used by all applications Fixed high level abstractions too costly for good efficiency Exo-kernel as an end-to-end argument 5 Exokernel Philosophy Expose hardware to libraryOS Not even mechanisms are implemented by exo-kernel They argue that mechanism is policy Exo-kernel worried only about protection not resource management 6 Design Principles Track resource ownership Ensure protection by guarding resource usage Revoke access to resources Expose hardware, allocation, names and revocation Basically validate binding, then let library manage the resource 7 Exokernel Architecture 8 Separating Security from Management Secure bindings – securely bind machine resources Visible revocation – allow libOSes to participate in resource revocation Abort protocol -
Microkernels Kishan Varma
KISHAN VARMA MICROKERNELS VAISHALI CHANANA AGENDA • MONOLITHIC KERNELS VS MICROKERNELS • FIRST GENERATION MICROKERNELS • SECOND GENERATION MICROKERNELS • EXOKERNEL • AEGIS – AN EXOKERNEL • ExOS Smaller Kernel : Easily maintained and less error MONOLITHIC VS MICROKERNELS prone. Highly modular structure More Flexible and Extensible Isolation of Server Malfunctions Device drivers can be run as servers Different file systems, different APIs coexist in one system Source : Wikipedia for Microkernels FIRST GENERATION MICROKERNELS • objects and mechanisms were lower-level with more general abstractions than UNIX • become widely accepted • General flexibility • Preserving UNIX compatibility •Mach’s external pager : • Kernel manages physical and virtual memory but forwards page faults to specific user-level tasks • After page fault, pagers return the page image to kernel • Handling h/w interrupts : • H/W interrupt as IPC messages for user-level process FIRST GENERATION MICROKERNELS (CONTD) •Weakness • Higher cost of RPC • Higher cost of memory references • Worst locality properties of combined microkernel code • High cache miss rate due to more modularity • Main memory is still managed by the microkernel SECOND GENERATION MICROKERNELS • Designing microkernel architecture from scratch • Believes that efficiency and flexibility require minimal set of abstractions • EXOKERNEL • Developed at MIT in 1994-95, works on idea that abstractions are costly and restrict flexibility • Multiplex hardware resources by minimal set of primitives • More details -
HIL: Designing an Exokernel for the Data Center
HIL: Designing an Exokernel for the Data Center Jason Hennessey Sahil Tikale Ata Turk Boston University Boston University Boston University [email protected] [email protected] [email protected] Emine Ugur Kaynar Chris Hill Peter Desnoyers Boston University Massachusetts Institute of Northeastern University [email protected] Technology [email protected] [email protected] Orran Krieger Boston University [email protected] Keywords cloud computing, datacenter management, bare Juju charms, Puppet manifests, etc.—much like an operat- metal, exokernel, IaaS, PaaS ing system hides disks and address spaces behind file sys- tems and processes. Different tools are better suited for some Abstract applications than others; e.g. Ironic is used for OpenStack deployment, while xCAT is well-suited for large High Per- We propose a new Exokernel-like layer to allow mutually formance Computing (HPC) deployments. untrusting physically deployed services to efficiently share Each of these tools takes control of the hardware it man- the resources of a data center. We believe that such a layer of- ages, and each provides very different higher-level abstrac- fers not only efficiency gains, but may also enable new eco- tions. A cluster operator must thus decide between, for ex- nomic models, new applications, and new security-sensitive ample, Ironic or MaaS for software deployment; and the data uses. A prototype (currently in active use) demonstrates that center operator who wants to use multiple tools is forced the proposed layer is viable, and can support a variety of ex- to statically partition the data center into silos of hardware. isting provisioning tools and use cases. -
Real-Time Audio Servers on BSD Unix Derivatives
Juha Erkkilä Real-Time Audio Servers on BSD Unix Derivatives Master's Thesis in Information Technology June 17, 2005 University of Jyväskylä Department of Mathematical Information Technology Jyväskylä Author: Juha Erkkilä Contact information: [email protected].fi Title: Real-Time Audio Servers on BSD Unix Derivatives Työn nimi: Reaaliaikaiset äänipalvelinsovellukset BSD Unix -johdannaisjärjestelmissä Project: Master's Thesis in Information Technology Page count: 146 Abstract: This paper covers real-time and interprocess communication features of 4.4BSD Unix derived operating systems, and especially their applicability for real- time audio servers. The research ground of bringing real-time properties to tradi- tional Unix operating systems (such as 4.4BSD) is covered. Included are some design ideas used in BSD-variants, such as using multithreaded kernels, and schedulers that can provide real-time guarantees to processes. Factors affecting the design of real- time audio servers are considered, especially the suitability of various interprocess communication facilities as mechanisms to pass audio data between applications. To test these mechanisms on a real operating system, an audio server and a client utilizing these techniques is written and tested on an OpenBSD operating system. The performance of the audio server and OpenBSD is analyzed, with attempts to identify some bottlenecks of real-time operation in the OpenBSD system. Suomenkielinen tiivistelmä: Tämä tutkielma kattaa reaaliaikaisuus- ja prosessien väliset kommunikaatio-ominaisuudet, keskittyen 4.4BSD Unix -johdannaisiin käyt- töjärjestelmiin, ja erityisesti siihen kuinka hyvin nämä soveltuvat reaaliaikaisille äänipalvelinsovelluksille. Tutkimusalueeseen sisältyy reaaliaikaisuusominaisuuk- sien tuominen perinteisiin Unix-käyttöjärjestelmiin (kuten 4.4BSD:hen). Mukana on suunnitteluideoita, joita on käytetty joissakin BSD-varianteissa, kuten säikeis- tetyt kernelit, ja skedulerit, jotka voivat tarjota reaaliaikaisuustakeita prosesseille. -
The Flask Security Architecture: System Support for Diverse Security Policies
The Flask Security Architecture: System Support for Diverse Security Policies Ray Spencer Secure Computing Corporation Stephen Smalley, Peter Loscocco National Security Agency Mike Hibler, David Andersen, Jay Lepreau University of Utah http://www.cs.utah.edu/flux/flask/ Abstract and even many types of policies [1, 43, 48]. To be gen erally acceptable, any computer security solution must Operating systems must be flexible in their support be flexible enough to support this wide range of security for security policies, providing sufficient mechanisms for policies. Even in the distributed environments of today, supporting the wide variety of real-world security poli this policy flexibility must be supported by the security cies. Such flexibility requires controlling the propaga mechanisms of the operating system [32]. tion of access rights, enforcing fine-grained access rights and supporting the revocation of previously granted ac Supporting policy flexibility in the operating system is cess rights. Previous systems are lacking in at least one a hard problem that goes beyond just supporting multi of these areas. In this paper we present an operating ple policies. The system must be capable of supporting system security architecture that solves these problems. fine-grained access controls on low-level objects used to Control over propagation is provided by ensuring that perform higher-level functions controlled by the secu the security policy is consulted for every security deci rity policy. Additionally, the system must ensure that sion. This control is achieved without significant perfor the propagation of access rights is in accordance with mance degradation through the use of a security decision the security policy. -
Harvard Cs252r Fa'13
Type Enforcement & Pluggable MAC Harvard CS252r Fa’13 Tuesday, October 22, 13 1 Practical Domain and Type Enforcement for UNIX • Badger, et al. 1995 • Trusted Information Systems Tuesday, October 22, 13 2 Domain and Type Enforcement • Every Subject is associated with a Domain • Every Object is associated with a Type Tuesday, October 22, 13 3 Boebart and Kain ’85 [7], page 23 introduces this a given user could have multiple subjects operating in diferent domains dynamically, it seems a subject and an object are associated with just one, statically: could be anything Domain and Type Enforcement • Domain Definition Table • Domain’s Access Rights to each Type • read, write, etc. • Domain Interaction Table • Domain’s Access Rights to other Domains • signal, create, destroy, etc. Tuesday, October 22, 13 4 Domain and Type Enforcement • Strict Superset of Lattice-Expressible Security Policies Tuesday, October 22, 13 5 Domain and Type Enforcement Manager budget designs Accountant Engineer salary Tuesday, October 22, 13 6 DTEL Domain and Type Enforcement Language • Encompasses Existing Security Policies • Hierarchical Types • Simple, Declarative Language Tuesday, October 22, 13 7 DTEL Operating System Entities File Hierarchy Process Hierarchy Figure 1: Mismatch Between Policy Concepts and System Structures trol configurations. A DTE specification includes ration: the type statement, the domain statement, the security attribute associations such as typelfile tnitial-domain statement, and the assign statement.’ associations as well as other access control in- The purpose of this section is not to fully document Tuesday,formation. October 22, 13 The language provides a high-level DTEL, but to demonstrate through a small example 8 view of information traditionally enurnerated in that a meaningful DTEL policy can be expressed com- type enforcement tables and includes facilities pletely in a form simple and concise enough to be ad- for superimposing security attribute bindings and ministered at reasonable cost.