![]() ![]() T-provides a general classification for the tuple itself. TC in each tuple t-which is the highest ofĪll attribute classification values within The value of the tuple classification attribute Schema R with n attributes would be represented as: The model we describe here is known as the multilevel model, because it allows classifications at multiple Is added to the relation attributes to provide a classification for each tupleĪs a whole. In addition, in some models, a tuple classification attribute TC Hence, each attribute A is associated with a classificationĮach attribute value in a tuple is associated with a corresponding securityĬlassification. The relational database model, it is common to consider attribute values and To incorporate multilevel security notions into Thus making it visible throughout the system. ForĮxample, a user (subject) with TS clearance may make a copy of an object withĬlassification TS and then write it back as a new object with classification U, Violation of this rule would allow information to flow from higher to lowerĬlassifications, which violates a basic tenet of multilevel security. It prohibits a subject from writing an object atĪ lower security classification than the subject’s security clearance. The obvious rule that no subject can read an object whose securityĬlassification is higher than the subject’s security clearance. The first restriction is intuitive and enforces Restrictions are enforced on data access based on the subject/object Subject S as class( S) and to the classification of an object O as class( O). We will refer to the clearance (classification) of a Used model for multilevel security, known as the Bell-LaPadula model, classifies each subject (user, account, program) and object (relation, tuple, column, view, operation) into one of the For simplicity, we will use the system with four securityĬlassification levels, where TS ≥ S ≥ C ≥ U, to illustrate our discussion. Other more complex securityĬlassification schemes exist, in which the security classes are organized in a (U), where TS is the highest level and U the lowest. Special versions of their RDBMSs that incorporate mandatory access control forĬlasses are top secret (TS), secret (S), confidential (C), and unclassified Some DBMS vendors-for example, Oracle-have released Military, and intelligence applications, as well as in many industrial andĬorporate applications. However, the need for multilevel security exists in government, It is important to note that mostĬommercial DBMSs currently provide mechanisms only for discretionary accessĬontrol. ![]() ![]() This approach, known as mandatory access control (MAC), would Security policy is needed that classifies data and users based on securityĬlasses. This is an all-or-nothing method: A user either has or does not have a certain Traditionally been the main security mechanism for relational database systems. The experimental results show that SELinux receives enough protection, and the performance degradation that ranges between 0.53% to 7.34% compared to the original by employing T-MAC.Mandatory Access Control and Role-Based AccessĬontrol technique of granting and revoking privileges on relations has The prototype is based on SELinux, which is the widely used MAC system, and the base of SEAndroid. Moreover, to protect T-MAC components that are not in the enclave, we not only provide a protection mechanism that enables TrustZone to protect the specific memory region from the compromised system, but establish a secure communication channel between the mobile system and the enclave as well. In the meanwhile, T-MAC provides a MAC supplicant client which runs in the mobile system kernel to effectively lookup policy decisions made by the back-end MAC service in the enclave and to enforce these rules on the system with trustworthy behaviors. T-Mac puts the MAC system into the enclave provided by the ARM TrustZone so as to avert the direct impact of the malicious code on the access decision process. In this paper, we propose a trusted MAC isolation framework called T-MAC to solve this problem. Therefore, for a trusted MAC system, it is desired to be isolated from the malicious mobile system at runtime. However, malicious code in the mobile system may have significantly impact to the integrity of these MAC systems by forcing them to make the wrong access control decision, because they are running on the same privilege level and memory address space. Mobile security has become increasingly important in mobile computing, hence mandatory access control (MAC) systems have been widely used to protect it.
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