/etc/security/audit_class is an ASCII system file that stores class definitions. Programs use the getauclassent(3BSM) routines to access this information.
The fields for each class entry are separated by colons. Each class entry is a bitmap and is separated from each other by a newline.
Each entry in the audit_class file has the form:
The fields are defined as follows:
The class mask.
The class name.
The description of the class.
The classes are now user-configurable. Each class is represented as a bit in the class mask which is an unsigned integer. Thus, there are 32 different classes available, plus two meta-classes -- all and no.
all represents a conjunction of all allowed classes, and is provided as a shorthand method of specifying all classes.
no is the "invalid" class, and any event mapped solely to this class will not be audited. (Turning auditing on to the all meta class will NOT cause events mapped solely to the no class to be written to the audit trail.)
Here is a sample of an audit_class file:
0x00000000:no:invalid class 0x00000001:fr:file read 0x00000002:fw:file write 0x00000004:fa:file attribute access 0x00000008:fm:file attribute modify 0x00000010:fc:file create 0x00000020:fd:file delete 0x00000040:cl:file close 0xffffffff:all:all classes
It is possible to deliberately turn on the no class in the kernel, in which case the audit trail will be flooded with records for the audit event AUE_NULL.
The functionality described in this man page is available only if the Basic Security Module (BSM) has been enabled. See bsmconv(1M) for more information.