Fault detection, isolation, and recovery fdir is a subfield of control engineering which concerns itself with monitoring a system, identifying when a fault has occurred, and pinpointing the type of fault and its location. Armlock is a hardwarebased fault isolation scheme for the arm architecture. The testing includes the response time with different delays and bandwidth requirements. In our approach, we enforce protection in software, by modifying the object code of a distrusted module so that it can never write or branch to an illegal address outside its domain. Scheduler activations, operating system support for multiprocessors. Selected as one of the best twenty papers in last twenty years at hpdc. Ambiguities that are present in current fault isolation methods will be significantly reduced by pfad, rovnack indicates. More recently, we developed a different approach to providing efficient, languageindependent, softwarebased fault isolation. Softwarebased fault isolation sfi implements such isolation via instruction rewriting, but previous research left the prac. Introduction isolationthe guarantee that one computation on a machine cannot a.
Dec srcs an2, one of the earliest gigabit lan switches. It poses new security challenges for sensor fault detection and isolation fdi and fault recovery fr research because the conventional redundancybased faulttolerant design is not effective against such faults. Softwarebased fault isolation sfi provides a framework to execute arbitrary code. Maintenance actions are defined by a list of basic maintenance tasks that define the procedure for repair or maintenance action. Doctors facilities in washington state have been attempting to lessen healing facility procured diseases hand hygienecentral line bundleventilators bundletimely antitoxins for surgery patientsmultidrug safe living beings i. Efficient softwarebased fault isolation proceedings of. This paper presents a modelbased methodology of residuals design for fault diagnosis of an automated manual transmission amt shifting actuator by employing structural analysis sa. Softwarebased fault isolation sfi, or sandboxing, is a technique to enforce security policies constraining memory access and control flow in untrusted binary code. However, the original sandboxing technique of wahbe et al. Fourteenth acm symposium on operating systems principles sosp, december 1993, pages 203 216. Fault injection, analysis, and radiation testing with drseus.
Using a novel technique of artificially enforcing alignment for jump targets, we show how a simple sandboxing implementation can be constructed for an architecture with variablelength instructions like the x86. It uniquely leverages the memory domain support in arm processors to create multiple sandboxes. Second, we modify the object code of a distrusted module to. In situations where the swapping out of lrus might be the standard procedure, pfad will enable realtime testing of components on the aircraft to keep turnaround times short. To achieve that, we have three design goals for armlock. The system model is applicable in conjunction with actual test results for determining at least one fault candidate representing a specific component of the sut likely to have caused a fault of the sut. That is, modify the programs so that they behave only in safe ways. This is also referred to as fault isolation, especially when need to show the distinction from fault detection. However, previous sfi techniques were applicable only to risc architectures 4, or their treatment of key security issues was faulty, incomplete, or never described publicly. Isa replaces cfi guard code with single instructions.
A problem of current approaches to sfi is that fault isolation is decoupled from the dynamic loader, which is treated as a black box. Isa support is provided for xfi in the form of boundscheck instructions. The starting point is a mathematical description of the system by means of a state space model. Winner of the standing ovation award for best powerpoint templates from presentations magazine. In this paper, we propose armlock, a hardwarebased fault isolation for arm. One way to provide fault isolation among cooperating software modules is to place each in its own address space. In computer security, a sandbox is a security mechanism for separating running programs, usually in an effort to mitigate system failures or software vulnerabilities from spreading.
Home it answers security fault isolation fault isolation tags. Computer software based on above procedure with the userfriendly interface, preprocessor, and postprocessor was developed for practical engineering design of. Efficient softwarebased fault isolation acm sigops. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Nacldroid complements these systems in the following way. However, for tightlycoupled modules, this solution incurs prohibitive context switch overhead. Softwarebased fault isolation sfi or sandboxing enforces such a policy by rewriting the untrusted code at the instruction level. Softwarebased, virtual sensors are so far not implemented in any of the industrial case studies, so that reconfiguration of functions via soft sensors, i. Our fault model comprises transient hardware faults, that is, the focus is on bit ips in memory and logical circuits.
Another way to get programs to behave in a manner consistent with a given security policy is by brainwashing. The result shall be a diagnoser that is able to detect and isolate faults of a prede ned fault set f. Implementation and analysis of software based fault isolation. Software based fault injectors also introduce the possibility of disturbing the processing workload in unintended ways. Cs 5 system security softwarebased fault isolation. However, software based fault injection also comes with disadvantages, for example certain comp onents, such as caches, are inaccessible by software for injection. Softwarebased fault isolation sfi provides a framework to execute arbitrary code while protecting the host system. Efficient softwarebased fault isolation robert wahbe steven lucco thomas e. Operating system services for wide area applications. Diagnosing priori unknown faults by radial basis function.
Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Compared to software guards, hardware support for cfi and xfi increases the efficiency and simplicity of enforcement. Pipes or remote procedure calls rpc are the most common birrel. Using multiple processes for multiple untrusted modules often yields unacceptable performance for frequently communicating modules, due to. In the second stage, detail design along with the stepbystep time history analysis was carried out for determination of foundation, superstructure and base isolation device. Softwarebased fault isolation softwarebased fault isolation sfi 58 can be used to con. Disclosed is a method for determining a system model describing a relation between applicable tests and components of a system under test sut. Safety requires no single points of failure blogger.
A comprehensive observerbased fault isolation procedure. A team led by harvard computer scientists, including two undergraduate students, has developed a new tool that could lead to increased security. Call stub sends call directly to exported procedure, no dispatch procedure. The availability of hardware virtualization extensions, however, does not make software based. Abft is used for detecting, locating, and correcting faults with a software procedure. Reliable isolation enables many useful kinds of coexistence. Software fault isolation, arm executables, program logic, automated theorem proving 1. Native code isolation for android applications 15 the above are some representative works in the. Ppt isolation technique powerpoint presentation free.
Implementation and analysis of software based fault isolation module or vice versa, some form of interdomain communication is used. Our approach belongs to a class of techniques known as softwarebased fault isolation sfi for short or sandboxing. Sfi directly modifies software at the instruction level to efficiently check that memory addresses and jump targets lie only in designated safe data and code regions. Systems integration offers answers to fault analysis. In case of softwarebased redundant execution, triple. Specific projects ive worked on include more recent at the bottom. Graham computer science division university of california berkeley, ca 94720 abstract one way to provide fault isolation among cooperating software modules is to place each in its own address space. To address these challenges, we present a redundancyfree method for uav sensor fdi and fr. Automated appliation of fault tolerance mechanisms in a. Instruction set architecture isa extension support is described for controlflow integrity cfi and for xfi memory protection. In this paper, we present a software approach to implementing fault isolation within a single address space. Us6587960b1 system model determination for failure.
We have argued that softwarebased fault isolation can be a practical tool in constructing secure systems. First, we load the code and data for a distrusted module into its own fault do main, a logically separate portion of the applications address space. On 32bit x86 platforms, sfi implementations usually leverage segment registers 20,62 to con. It is often used to execute untested or untrusted programs or code, possibly from unverified or untrusted third parties, suppliers, users or websites, without risking harm to the host machine or operating system. It is designed to securely isolate untrusted modules from the host application so that they can safely coexist in a single address space. The fault diagnosis procedure is divided into two consequent phases. Difficilesupported by the washington state hospital association. A guide to maintainability prediction with milhdbk472. Is there any piece of software preferably opensourcefreeware. This is embodied by a recent approach to security known as softwarebased fault isolation sfi. Redundancyfree uav sensor fault isolation and recovery. There is an edge v i, v j if function v i calls function v j. Other metrics that can be obtained from maintainability prediction mttr software based on milhdbk472 include.
A direct pattern recognition of sensor readings that indicate a fault and an analysis of the discrepancy between the sensor readings. Tom burkleaux s slides for fault domain and cross fault domain communication figs on efficient software based isolation carl yaos slides for examples of segment matching and address sandboxing slides on efficient software based isolationon efficient software based isolationsandboxing sandboxing ssffiirisc. The loader is a trusted component of the application, and faults in the loader are problematic. Using remote procedure call rpc bn84, modules in separate address spaces can call into each. Efficient softwarebased fault isolation by wahbe, lucco, anderson, graham 46. The number of faults to be successfully recognized and corrected per processing interval is dependent on the respective fault detection and fault tolerance mechanisms. Your gift is important to us and helps support critical opportunities for students and faculty alike, including lectures, travel support, and any number of educational events that augment the classroom experience. However, in order to carry out suggested reconfiguration and selfhealing measures fault isolation is mandatory.
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