Daniel Hagimont. Protection in the Guide object{oriented distributed system. In Proc. ECOOP 1994, LNCS, pages 280-298. Springer, 1994.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....model for non distributed environments is [RSC92] This model does distinguish between di erent classes of principals but again does not separate policy speci cations from application implementation. The concept of views as an access control concept was rst used for a distributed object system in [Hag94]. Views are also used for protection in relational and object oriented databases[SLT91] Their use for access control purposes resembles the use of type abstraction as a protection concept. Unlike database views that can span multiple types, a view in our model is restricted to objects of a single ....

Daniel Hagimont. Protection in the Guide object{oriented distributed system. In Proc. ECOOP 1994, LNCS, pages 280-298. Springer, 1994.

....for each active principal. A mechanism is required to control access to the individual operations of objects within a protection domain. A language based model for the specification of access rights and their enforcement in the GUIDE object oriented language has been described by Hagimont [6]. It is based on the compilation of operation dispatch tables restricted according to the rights of the current process. Objects are shared through DSVM but each protection domain requires a different dispatch table. The different dispatch tables should appear at the same location in all of the ....

Hagimont, D. Protection in the Guide object-oriented distributed system. To appear in Proceedings of ECOOP 94.

....5, 1995 [Dollimore and Wang 1993] For example, only the user who created an entry in a diary for a meeting should be allowed to alter or cancel it. Objects typically have many operations, so the variety of possible rights can be huge. To manage complexity and improve performance, in Guide [Hagimont 1994, Balter et al. 1994] the operations available on an object are grouped together into views to which principals may gain or be denied access. Views are similar to the views used in databases to grant users the right to access selected information. Views are defined statically as part of the ....

Hagimont, D. 1994, Protection in the Guide object-oriented distributed system, ECOOP 94.

....also arises in [Dollimore and Wang 1993] For example, only the user who created an entry in a diary for a meeting should be allowed to alter or cancel it. Objects typically have many operations, so the variety of possible rights can be huge. To manage complexity and improve performance, in Guide [Hagimont 1994, Balter et al. 1994] the operations available on an object are grouped together into views to which principals may gain or be denied access. Views are similar to the views used in databases to grant users the right to access selected information. Views are defined statically as part of the ....

Hagimont, D. 1994, Protection in the Guide object-oriented distributed system, ECOOP 94.

....meeting that conflicts with existing meetings) or (b) to the properties of an object (e.g. who created it) A requirement similar to (b) also arises in [3] Objects typically have many operations, so the variety of possible rights can be huge. To manage complexity and improve performance, in Guide [5] the operations available on an object are grouped together into views to which principals may gain or be denied access. Views are similar to the views used in databases to grant users the right to access selected information. Views are defined statically as part of the class of an object. This ....

....typically of a chain of invocations by one object on another. In principle, the authorisation should be checked at each invocation in the chain. Protection in distributed object systems can be made more efficient by reducing the number of invocations at which the checks must be applied. The Guide [5] and CACL [11] systems have devoted considerable efforts to this issue. Late binding in object oriented programming systems is generally achieved by means of dispatch vectors which map invocations to method code at run time. An important aspect of the implementation of both Guide and CACL is the ....

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Hagimont, D., Protection in the Guide object-oriented distributed system, ECOOP 94.

.... [Accetta 86] or Chorus [Rozier 88] Several research prototypes have been built following this last approach since the early nineties (Munin [Carter 91] Opal [Chase 92] Cricket [Shekita 91] in the United States and EOS [Gruber 92a] COOL [Lea 93] Gothic [Ban tre 94] FTM [Ban tre 91a] Guide 2 [Hagimont 94a] in Europe) The success of this third approach can be explained by the additional flexibility and efficiency of micro kernels compared to monolithic systems like Unix, while keeping Unix functionalities available. This explains why microkernels, which were primarily designed for defining an ....

.... has led to the design and implementation, on top of Unix, of an object based language called Guide [Krakowiak 90] and its associated distributed run time support [Balter 91] A second phase of the project began in 1990 and aimed at building a more general version of the platform, named Eliott [Hagimont 94a] on top of the Mach 3.0 micro kernel. Compared to the first version of Guide, Eliott supplies generic support to object oriented languages. Eliott provides a distributed abstract machine that can be accessed by applications written both in the Guide programming language and in a version of C ....

Hagimont, D.,Protection in the Guide Object-Oriented Distributed Support in the Guide System, European Conference on Object-Oriented Programming (ECOOP'94), Bologna, July 1994.

....This avoids a recursion of access rights on access rights, access rights on access rights on access rights, and so on. Modification of access rights is discussed in more detail in section 3.7. 3. 6 Views A view is a subset of the set of access types defined for a particular (class of) object [Hag94, CD94b]. There is a similarity with views on databases. Views can be used to organize large sets of access rights into managable proportions. An example: In the BSCW system, an object of type folder has 12 different rights: add article, add document, add folder, add URL, add versions, delete (from the ....

D. Hagimont. Protection in the Guide Object-Oriented Distributed System. ECOOP'94, Bologna (1994), pp. 280--298.

....of this mechanism consists in a simple check to verify, whenever an inter context call involves different owners (8) if the called object has a true visibility tag. 3.5. 2 Lessons learned and related work A more complete study of protection in object based systems in presented in [Hagimont93] . However, we now summarize the comparison with other approaches which justifies our design. Operating systems that provide mechanisms for access rights control may be roughly divided in two trends: 8) An inter context call may involve two contexts associated with the same owner, but when these ....

D. Hagimont, Protection in the Guide object-oriented distributed system, ( Accepted at ECOOP'94), Bull-IMAG/Systmes, Grenoble, December 1993.

....environment. We conclude in section 4. 2 Protection Model 2.1 Motivations Protection is a crucial aspect of distributed computing, in particular when untrusted users co operate using shared objects. Several protection models have been proposed [Organick 72, Wulf 74, Kowalski 90, Cabrera 92, Hagimont 94] among these are capability based models [Levy 84] Capabilities are very convenient because of their flexibility, allowing the implementation of various execution and protection policies. However, in all the proposed approaches (e.g. Tanenbaum 86, Chase 94] capabilities are made available at ....

D. Hagimont. Protection in the Guide Object-Oriented Distributed System, Proc. of the 8th European Conference on Object-Oriented Programming, pp. 280-298 , July 1994.

....it in a single address space operating system based on distributed shared memory. 1. Introduction Protection is a crucial aspect of distributed computing, in particular when users co operate using shared objects or shared memory. Several protection models have been proposed [9] 14] 6] 2][5], among which capability based Institut National de Recherche d Informatique et d Automatique (INRIA) y Institut National Polytechnique de Grenoble z IMAG LSR is a joint laboratory of Centre National de la Recherche Scientifique (CNRS) Institut National Polytechnique de Grenoble, and ....

D. Hagimont. Protection in the guide object-oriented distributed system. Proc. of the 8th European Conference on Object-Oriented Programming, pages 280--298, July 1994.

....objects. Since CORBA has become a standard in the object community, designing a protection service that is well integrated within the CORBA framework is a very important issue. Several well defined protection models have been proposed, among which access control list based models ( Kowalski 90] Hagimont 94] and capability based models ( Levy 84] Tanenbaum 86] but integrating one of these protection models in a CORBA environment is still an open issue. In this paper, we report on our experiment in designing and integrating a capabilitybased protection model in a CORBA environment. When designing ....

D. Hagimont. Protection in the Guide Object-Oriented Distributed System, Proc. of the 8th European Conference on Object-Oriented Programming, pp. 280-298 , July 1994.

....environment. We conclude in section 4. 2 Protection Model 2.1 Motivations Protection is a crucial aspect of distributed computing, in particular when untrusted users co operate using shared objects. Several protection models have been proposed [Organick 72, Wulf 74, Kowalski 90, Cabrera 92, Hagimont 94] among these are capability based models [Levy 84] Capabilities are very convenient because of their flexibility, allowing the implementation of various execution and protection policies. However, in all the proposed approaches (e.g. Tanenbaum 86, Chase 94] capabilities are made available at ....

D. Hagimont. Protection in the Guide Object-Oriented Distributed System, Proc. of the 8th European Conference on Object-Oriented Programming, pp. 280-298 , July 1994.

....4.1 Object Views In general the access control mechanism of an objectoriented system can either deny access to an object or restrict the set of operations that the subject is allowed to invoke on the object. The set of authorized operations is commonly called the subject s view on the object [6]. In a multiuser application, object servers often wish to present dioeerent subjects with dioeerent views on the servers objects. Although domain capabilities allow authorization of individual operations, it is often convenient for servers to manage access control by views on the object. A quick ....

D. Hagimont, P-Y. Chevalier, A. Freyssinet, S. Krakowiak, S. Lacourte, J. Mossi#re, and X. Rousset de Pina. Protection in the Guide objectoriented distributed system. In 8th European Confereence on ObjectOriented Programming (ECOOP), pages 280298, Bologna, Italy, July 1994.

....space operating system based on distributed shared memory. 1 Introduction Protection is a crucial aspect of distributed computing, in particular when users cooperate using shared objects or shared memory. Several protection models have been proposed [Organick 72, Wulf 74, Kowalski 90, Cabrera 92, Hagimont 94] among which capability based protection [Levy 84] Capabilities are very convenient because of their flexibility, allowing the implementation of various execution and protection models. However, in all the proposed approaches (e.g. Tanenbaum 86, Chase 94] capabilities are made available at ....

D. Hagimont. Protection in the Guide Object-Oriented Distributed System, Proc. of the 8th European Conference on Object-Oriented Programming, pp. 280-298 , July 1994.

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