http://50.77.162.165/mediawiki/index.php?feed=atom&target=Clandau&title=Special%3AContributions 2026-04-25T20:22:37Z From Erights MediaWiki 1.15.5-7 http://50.77.162.165/wiki/Ambient_authority 2009-06-11T23:04:31Z

<p>Clandau:&#32;Restore credit to coiners</p> <hr /> <div>== Draft Definition ==<br /> <br /> A [[subject]] may have several different [[permission]]s. '''Ambient authority''' is authority that can be used without having to identify which specific permission is required. In an ambient authority system, when a subject requests an action (typically by naming an object and an operation on that object), the action is allowed if the subject has any permission for the action. <br /> <br /> In contrast, in a designated authority system, a subject explicitly identifies a subset (usually one) of its permissions, and the action is allowed only if permitted by that subset of permissions. <br /> <br /> In an ambient authority system, often there is no way to identify a specific permission, so there is no concept of having different permissions. <br /> <br /> == Comment ==<br /> <br /> Several access control models were invented and implemented to enable restriction of ambient authority of subjects. Many of them are:<br /> * either weak (we cannot follow the [[POLA|principle of least authority]])<br /> * or convoluted (it is hard to learn how to work with this model and be sure about [[authority]] of subjects).<br /> Things become more &quot;interesting&quot; if we have to consider different security policies enforced via different alternative security mechanisms for the same type of objects and for different type of objects and the relevant transitivity relationship.<br /> <br /> == Examples of ambient authority ==<br /> <br /> All UNIX processes run by some user have ''ambient authority'' to manipulate all files owned by that user.<br /> <br /> All UNIX processes have ''ambient authority'' to listen to TCP or UDP ports 1024--65535.<br /> <br /> All UNIX processes have ''ambient authority'' to send any signal to any other UNIX process.<br /> <br /> == Acknowledgement ==<br /> <br /> The term ''ambient authority'' was coined by Dean Tribble and Mark S. Miller.</div>

Clandau http://50.77.162.165/wiki/Ambient_authority 2009-06-11T22:04:40Z

<p>Clandau:&#32;Completely replace the definition</p> <hr /> <div>== Draft Definition ==<br /> <br /> A [[subject]] may have several different [[permission]]s. '''Ambient authority''' is authority that can be used without having to identify which specific permission is required. In an ambient authority system, when a subject requests an action (typically by naming an object and an operation on that object), the action is allowed if the subject has any permission for the action. <br /> <br /> In contrast, in a designated authority system, a subject explicitly identifies a subset (usually one) of its permissions, and the action is allowed only if permitted by that subset of permissions. <br /> <br /> In an ambient authority system, often there is no way to identify a specific permission, so there is no concept of having different permissions. <br /> <br /> == Comment ==<br /> <br /> Several access control models were invented and implemented to enable restriction of ambient authority of subjects. Many of them are:<br /> * either weak (we cannot follow the [[POLA|principle of least authority]])<br /> * or convoluted (it is hard to learn how to work with this model and be sure about [[authority]] of subjects).<br /> Things become more &quot;interesting&quot; if we have to consider different security policies enforced via different alternative security mechanisms for the same type of objects and for different type of objects and the relevant transitivity relationship.<br /> <br /> == Examples of ambient authority ==<br /> <br /> All UNIX processes run by some user have ''ambient authority'' to manipulate all files owned by that user.<br /> <br /> All UNIX processes have ''ambient authority'' to listen to TCP or UDP ports 1024--65535.<br /> <br /> All UNIX processes have ''ambient authority'' to send any signal to any other UNIX process.</div>

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