The Experts below are selected from a list of 684048 Experts worldwide ranked by ideXlab platform
Yoshio Turner - One of the best experts on this subject based on the ideXlab platform.
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cruz Application transparent distributed checkpoint restart on standard operating systems
Dependable Systems and Networks, 2005Co-Authors: Gopalakrishnan Janakiraman, J R Santos, Dinesh Kumar Subhraveti, Yoshio TurnerAbstract:We present a new distributed checkpoint-restart mechanism, Cruz, that works without requiring Application, library, or base kernel modifications. This mechanism provides comprehensive support for checkpointing and restoring Application State, both at user level and within the OS. Our implementation builds on Zap, a process migration mechanism, implemented as a Linux kernel module, which operates by interposing a thin layer between Applications and the OS. In particular, we enable support for networked Applications by adding migratable IP and MAC addresses, and checkpoint-restart of socket buffer State, socket options, and TCP State. We leverage this capability to devise a novel method for coordinated checkpoint-restart that is simpler than prior approaches. For instance, it eliminates the need to flush communication channels by exploiting the packet re-transmission behavior of TCP and existing OS support for packet filtering. Our experiments show that the overhead of coordinating checkpoint-restart is negligible, demonstrating the scalability of this approach.
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DSN - Cruz: Application-Transparent Distributed Checkpoint-Restart on Standard Operating Systems
2005 International Conference on Dependable Systems and Networks (DSN'05), 1Co-Authors: Gopalakrishnan Janakiraman, J R Santos, Dinesh Kumar Subhraveti, Yoshio TurnerAbstract:We present a new distributed checkpoint-restart mechanism, Cruz, that works without requiring Application, library, or base kernel modifications. This mechanism provides comprehensive support for checkpointing and restoring Application State, both at user level and within the OS. Our implementation builds on Zap, a process migration mechanism, implemented as a Linux kernel module, which operates by interposing a thin layer between Applications and the OS. In particular, we enable support for networked Applications by adding migratable IP and MAC addresses, and checkpoint-restart of socket buffer State, socket options, and TCP State. We leverage this capability to devise a novel method for coordinated checkpoint-restart that is simpler than prior approaches. For instance, it eliminates the need to flush communication channels by exploiting the packet re-transmission behavior of TCP and existing OS support for packet filtering. Our experiments show that the overhead of coordinating checkpoint-restart is negligible, demonstrating the scalability of this approach.
Ling Liu - One of the best experts on this subject based on the ideXlab platform.
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ICDCS - REMO: Resource-Aware Application State Monitoring for Large-Scale Distributed Systems
2009 29th IEEE International Conference on Distributed Computing Systems, 2009Co-Authors: Shicong Meng, Srinivas Kashyap, Chitra Venkatramani, Ling LiuAbstract:To observe, analyze and control large scale distributed systems and the Applications hosted on them, there is an increasing need to continuously monitor performance attributes of distributed system and Application States. This results in Application State monitoring tasks that require fine-grained attribute information to be collected from relevant nodes efficiently. Existing approaches either treat multiple Application State monitoring tasks independently and build ad-hoc monitoring trees for each task, or construct a single static monitoring tree for multiple tasks. We argue that a careful planning of multiple Application State monitoring tasks by jointly considering multi-task optimization and node level resource constraints can provide significant gains in performance and scalability. In this paper, we present REMO, a REsource-aware Application State MOnitoring system. REMO produces a forest of optimized monitoring trees through iterations of two phases, one phase exploring cost sharing opportunities via estimation and the other refining the monitoring plan through resource-sensitive tree construction. Our experimental results include those gathered by deploying REMO on a BlueGene/P rack running IBM's large-scale distributed streaming system - System S. Using REMO running over 200 monitoring tasks for an Application deployed across 200 nodes results in a 35%-45% decrease in the percentage error of collected attributes compared to existing schemes.
Mathias Schwarz - One of the best experts on this subject based on the ideXlab platform.
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Automated Detection of Client-State Manipulation Vulnerabilities
ACM Transactions on Software Engineering and Methodology, 2014Co-Authors: Anders Møller, Mathias SchwarzAbstract:Web Application programmers must be aware of a wide range of potential security risks. Although the most common pitfalls are well described and categorized in the literature, it remains a challenging task to ensure that all guidelines are followed. For this reason, it is desirable to construct automated tools that can assist the programmers in the Application development process by detecting weaknesses. Many vulnerabilities are related to Web Application code that stores references to Application State in the generated HTML documents to work around the Statelessness of the HTTP protocol. In this article, we show that such client-State manipulation vulnerabilities are amenable to tool-supported detection. We present a static analysis for the widely used frameworks Java Servlets, JSP, and Struts. Given a Web Application archive as input, the analysis identifies occurrences of client State and infers the information flow between the client State and the shared Application State on the server. This makes it possible to check how client-State manipulation performed by malicious users may affect the shared Application State and cause leakage or modifications of sensitive information. The warnings produced by the tool help the Application programmer identify vulnerabilities before deployment. The inferred information can also be applied to configure a security filter that automatically guards against attacks at runtime. Experiments on a collection of open-source Web Applications indicate that the static analysis is able to effectively help the programmer prevent client-State manipulation vulnerabilities. The analysis detects a total of 4,802 client-State parameters in ten Applications, whereof 4,437 are classified as safe and 241 reveal exploitable vulnerabilities.
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ICSE - Automated detection of client-State manipulation vulnerabilities
2012Co-Authors: Anders Møller, Mathias SchwarzAbstract:Web Application programmers must be aware of a wide range of potential security risks. Although the most common pitfalls are well described and categorized in the literature, it remains a challenging task to ensure that all guidelines are followed. For this reason, it is desirable to construct automated tools that can assist the programmers in the Application development process by detecting weaknesses. Many vulnerabilities are related to web Application code that stores references to Application State in the generated HTML documents to work around the Statelessness of the HTTP protocol. In this paper, we show that such client-State manipulation vulnerabilities are amenable to tool supported detection. We present a static analysis for the widely used frameworks Java Servlets, JSP, and Struts. Given a web Application archive as input, the analysis identifies occurrences of client State and infers the information flow between the client State and the shared Application State on the server. This makes it possible to check how client-State manipulation performed by malicious users may affect the shared Application State and cause leakage or modifications of sensitive information. The warnings produced by the tool help the Application programmer identify vulnerabilities. Moreover, the inferred information can be applied to configure a security filter that automatically guards against attacks. Experiments on a collection of open source web Applications indicate that the static analysis is able to effectively help the programmer prevent client-State manipulation vulnerabilities.
A Mellouk - One of the best experts on this subject based on the ideXlab platform.
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Adaptive State Consistency for Distributed ONOS Controllers
2018Co-Authors: F. Bannour, S. Souihi, A MelloukAbstract:Logically-centralized but physically-distributed SDN controllers are mainly used in large-scale SDN networks for scalability, performance and reliability reasons. These controllers host various Applications that have different requirements in terms of performance, availability and consistency. Current SDN controller platform designs employ conventional strong consistency models so that the SDN Applications running on top of the distributed controllers can benefit from strong consistency guarantees for network State updates. However, in large-scale deployments, ensuring strong consistency is usually achieved at the cost of generating performance overheads and limiting system availability. That makes weaker optimistic consistency models such as the eventual consistency model more attractive for SDN controller platform Applications with high-availability and scalability requirements. In this paper, we argue that the use of the standard eventual consistency models, though a necessity for efficient scalability in modern SDN systems, provides no bounds on the State inconsistencies tolerated by the SDN Applications. To remedy that, we propose an adaptive consistency model for the distributed ONOS controllers following the notion of continuous and compulsory (per-controller) eventual consistency, where network Application States adapt their eventual consistency level dynamically at run-time based on the observed State inconsistencies under changing network conditions. When compared to the ONOS approach to static eventual consistency, our approach proved efficient in minimizing State synchronization overheads while taking into account Application State consistency SLAs and without compromising the Application requirements of high-availability, in the context of large-scale SDN networks.
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GLOBECOM - Adaptive State Consistency for Distributed ONOS Controllers
2018 IEEE Global Communications Conference (GLOBECOM), 2018Co-Authors: F. Bannour, S. Souihi, A MelloukAbstract:-Logically-centralized but physically-distributed SDN controllers are mainly used in large-scale SDN networks for scalability, performance and reliability reasons. These controllers host various Applications that have different requirements in terms of performance, availability and consistency. Current SDN controller platform designs employ conventional strong consistency models so that the SDN Applications running on top of the distributed controllers can benefit from strong consistency guarantees for network State updates. However, in large-scale deployments, ensuring strong consistency is usually achieved at the cost of generating performance overheads and limiting system availability. That makes weaker optimistic consistency models such as the eventual consistency model more attractive for SDN controller platform Applications with high-availability and scalability requirements. In this paper, we argue that the use of the standard eventual consistency models, though a necessity for efficient scalability in modern SDN systems, provides no bounds on the State inconsistencies tolerated by the SDN Applications. To remedy that, we propose an adaptive consistency model for the distributed ONOS controllers following the notion of continuous and compulsory (per-controller) eventual consistency, where network Application States adapt their eventual consistency level dynamically at runtime based on the observed State inconsistencies under changing network conditions. When compared to the ONOS approach to static eventual consistency, our approach proved efficient in minimizing State synchronization overheads while taking into account Application State consistency SLAs and without compromising the Application requirements of high-availability, in the context of large-scale SDN networks.
Gopalakrishnan Janakiraman - One of the best experts on this subject based on the ideXlab platform.
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cruz Application transparent distributed checkpoint restart on standard operating systems
Dependable Systems and Networks, 2005Co-Authors: Gopalakrishnan Janakiraman, J R Santos, Dinesh Kumar Subhraveti, Yoshio TurnerAbstract:We present a new distributed checkpoint-restart mechanism, Cruz, that works without requiring Application, library, or base kernel modifications. This mechanism provides comprehensive support for checkpointing and restoring Application State, both at user level and within the OS. Our implementation builds on Zap, a process migration mechanism, implemented as a Linux kernel module, which operates by interposing a thin layer between Applications and the OS. In particular, we enable support for networked Applications by adding migratable IP and MAC addresses, and checkpoint-restart of socket buffer State, socket options, and TCP State. We leverage this capability to devise a novel method for coordinated checkpoint-restart that is simpler than prior approaches. For instance, it eliminates the need to flush communication channels by exploiting the packet re-transmission behavior of TCP and existing OS support for packet filtering. Our experiments show that the overhead of coordinating checkpoint-restart is negligible, demonstrating the scalability of this approach.
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DSN - Cruz: Application-Transparent Distributed Checkpoint-Restart on Standard Operating Systems
2005 International Conference on Dependable Systems and Networks (DSN'05), 1Co-Authors: Gopalakrishnan Janakiraman, J R Santos, Dinesh Kumar Subhraveti, Yoshio TurnerAbstract:We present a new distributed checkpoint-restart mechanism, Cruz, that works without requiring Application, library, or base kernel modifications. This mechanism provides comprehensive support for checkpointing and restoring Application State, both at user level and within the OS. Our implementation builds on Zap, a process migration mechanism, implemented as a Linux kernel module, which operates by interposing a thin layer between Applications and the OS. In particular, we enable support for networked Applications by adding migratable IP and MAC addresses, and checkpoint-restart of socket buffer State, socket options, and TCP State. We leverage this capability to devise a novel method for coordinated checkpoint-restart that is simpler than prior approaches. For instance, it eliminates the need to flush communication channels by exploiting the packet re-transmission behavior of TCP and existing OS support for packet filtering. Our experiments show that the overhead of coordinating checkpoint-restart is negligible, demonstrating the scalability of this approach.