5.10 Resource Attributes

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A Security Descriptor MAY carry metadata about the object it protects — descriptive properties rather than access rules. These are resource attributes: name-value pairs stored as SYSTEM_RESOURCE_ATTRIBUTE_ACEs in the SACL.

Resource attributes do not grant or deny access. They exist so that conditional ACEs in the DACL can reference properties of the object during evaluation. A conditional allow ACE might say "grant read access if @User.clearance >= @Resource.confidentiality."

Each resource attribute ACE encodes a single named, typed, multi-valued attribute. The name is a string. Values MAY be integers, strings, booleans, SIDs, or byte arrays. The attribute data uses the claim entry format defined in §5.9.

Multiple resource attribute ACEs MAY appear in the same SACL, each carrying a different attribute. If two ACEs carry the same attribute name, the first one wins — duplicates are silently ignored. Name comparison is case-insensitive, matching the conditional expression evaluator's attribute name matching.

An inherit-only SYSTEM_RESOURCE_ATTRIBUTE_ACE does not apply to the object it is attached to and MUST be ignored during resource-attribute extraction.

Resource attributes are extracted from the SACL before the DACL walk begins, so they are available when conditional expressions need them.

A resource attribute marked CLAIM_SECURITY_ATTRIBUTE_MANDATORY is protected metadata. Set-security operations MUST preserve each mandatory resource attribute unless the caller has SeTcbPrivilege, as described in the Peios Kernel TRM §3.4.2.

5.10.1 Claim types #

Boolean values MUST be normalised to 1 (true) or 0 (false) at resolution time (when the conditional expression evaluator reads the attribute value), regardless of the wire encoding.

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