AUDIT.LOG(5) MidnightBSD File Formats Manual AUDIT.LOG(5)

NAME

audit — Basic Security Module (BSM) file format

DESCRIPTION

The audit file format is based on Sun’s Basic Security Module (BSM) file format, a token-based record stream to represent system audit data. This file format is both flexible and extensible, able to describe a broad range of data types, and easily extended to describe new data types in a moderately backward and forward compatible way.

BSM token streams typically begin and end with a ‘‘file’’ token, which provides time stamp and file name information for the stream; when processing a BSM token stream from a stream as opposed to a single file source, file tokens may be seen at any point between ordinary records identifying when particular parts of the stream begin and end. All other tokens will appear in the context of a complete BSM audit record, which begins with a ‘‘header’’ token, and ends with a ‘‘trailer’’ token, which describe the audit record. Between these two tokens will appear a variety of data tokens, such as process information, file path names, IPC object information, MAC labels, socket information, and so on.

The BSM file format defines specific token orders for each record event type; however, some variation may occur depending on the operating system in use, what system options, such as mandatory access control, are present.

This manual page documents the common token types and their binary format, and is intended for reference purposes only. It is recommended that application programmers use the libbsm(3) interface to read and write tokens, rather than parsing or constructing records by hand.

File Token
The ‘‘file’’ token is used at the beginning and end of an audit log file to indicate when the audit log begins and ends. It includes a pathname so that, if concatenated together, original file boundaries are still observable, and gaps in the audit log can be identified. A ‘‘file’’ token can be created using au_to_file(3).

Header Token
The ‘‘header’’ token is used to mark the beginning of a complete audit record, and includes the length of the total record in bytes, a version number for the record layout, the event type and subtype, and the time at which the event occurred. A 32-bit ‘‘header’’ token can be created using au_to_header32(3); a 64-bit ‘‘header’’ token can be created using au_to_header64(3).

Expanded Header Token
The ‘‘expanded header’’ token is an expanded version of the ‘‘header’’ token, with the addition of a machine IPv4 or IPv6 address. A 32-bit extended ‘‘header’’ token can be created using au_to_header32_ex(3); a 64-bit extended ‘‘header’’ token can be created using au_to_header64_ex(3).

Trailer Token
The ‘‘trailer’’ terminates a BSM audit record, and contains a magic number, TRAILER_PAD_MAGIC and length that can be used to validate that the record was read properly. A ‘‘trailer’’ token can be created using au_to_trailer(3).

Arbitrary Data Token
The ‘‘arbitrary data’’ token contains a byte stream of opaque (untyped) data. The size of the data is calculated as the size of each unit of data multipled by the number of units of data. A ‘‘How to print’’ field is present to specify how to print the data, but interpretation of that field is not currently defined. An ‘‘arbitrary data’’ token can be created using au_to_data(3).

in_addr Token
The ‘‘in_addr’’ token holds a network byte order IPv4 or IPv6 address. An ‘‘in_addr’’ token can be created using au_to_in_addr(3) for an IPv4 address, or au_to_in_addr_ex(3) for an IPv6 address.

See the BUGS section for information on the storage of this token.

Expanded in_addr Token
The ‘‘expanded in_addr’’ token ...

See the BUGS section for information on the storage of this token.

XXXX

ip Token
The ‘‘ip’’ token contains an IP packet header in network byte order. An ‘‘ip’’ token can be created using au_to_ip(3).

Expanded ip Token
The ‘‘expanded ip’’ token ...

XXXX

iport Token
The ‘‘iport’’ token stores an IP port number in network byte order. An ‘‘iport’’ token can be created using au_to_iport(3).

Path Token
The ‘‘path’’ token contains a pathname. A ‘‘path’’ token can be created using au_to_path(3).

path_attr Token
The ‘‘path_attr’’ token contains a set of NUL-terminated path names. The libbsm(3) API cannot currently create a ‘‘path_attr’’ token.

Process Token
The ‘‘process’’ token contains a description of the security properties of a process involved as the target of an auditable event, such as the destination for signal delivery. It should not be confused with the ‘‘subject’’ token, which describes the subject performing an auditable event. This includes both the traditional UNIX security properties, such as user IDs and group IDs, but also audit information such as the audit user ID and session. A ‘‘process’’ token can be created using au_to_process32(3) or au_to_process64(3).

Expanded Process Token
The ‘‘expanded process’’ token contains the contents of the ‘‘process’’ token, with the addition of a machine address type and variable length address storage capable of containing IPv6 addresses. An ‘‘expanded process’’ token can be created using au_to_process32_ex(3) or au_to_process64_ex(3).

Return Token
The ‘‘return’’ token contains a system call or library function return condition, including return value and error number associated with the global variable errno. A ‘‘return’’ token can be created using au_to_return32(3) or au_to_return64(3).

Subject Token
The ‘‘subject’’ token contains information on the subject performing the operation described by an audit record, and includes similar information to that found in the ‘‘process’’ and ‘‘expanded process’’ tokens. However, those tokens are used where the process being described is the target of the operation, not the authorizing party. A ‘‘subject’’ token can be created using au_to_subject32(3) and au_to_subject64(3).

Expanded Subject Token
The ‘‘expanded subject’’ token consists of the same elements as the ‘‘subject’’ token, with the addition of type/length and variable size machine address information in the terminal ID. An ‘‘expanded subject’’ token can be created using au_to_subject32_ex(3) or au_to_subject64_ex(3).

System V IPC Token
The ‘‘System V IPC’’ token contains the System V IPC message handle, semaphore handle or shared memory handle. A System V IPC token may be created using +.Xr au_to_ipc 3 .

Text Token
The ‘‘text’’ token contains a single NUL-terminated text string. A ‘‘text’’ token may be created using au_to_text(3).

Attribute Token
The ‘‘attribute’’ token describes the attributes of a file associated with the audit event. As files may be identified by 0, 1, or many path names, a path name is not included with the attribute block for a file; optional ‘‘path’’ tokens may also be present in an audit record indicating which path, if any, was used to reach the object. An ‘‘attribute’’ token can be created using au_to_attr32(3) or au_to_attr64(3).

Groups Token
The ‘‘groups’’ token contains a list of group IDs associated with the audit event. A ‘‘groups’’ token can be created using au_to_groups(3).

System V IPC Permission Token
The ‘‘System V IPC permission’’ token contains a System V IPC access permissions. A System V IPC permission token may be created using au_to_ipc_perm(3).

Arg Token
The ‘‘arg’’ token contains informations about arguments of the system call. Depending on the size of the desired argument value, an Arg token may be created using au_to_arg32(3) or au_to_arg64(3).

exec_args Token
The ‘‘exec_args’’ token contains informations about arguements of the exec() system call. An exec_args token may be created using au_to_exec_args(3).

exec_env Token
The ‘‘exec_env’’ token contains current eviroment variables to an exec() system call. An exec_args token may be created using au_to_exec_env(3).

Exit Token
The ‘‘exit’’ token contains process exit/return code information. An ‘‘exit’’ token can be created using au_to_exit(3).

Socket Token
The ‘‘socket’’ token contains informations about UNIX domain and Internet sockets. Each token has four or eight fields. Depend on type of socket a socket token may be created using au_to_sock_unix(3), au_to_sock_inet32(3) or au_to_sock_inet128(3).

Expanded Socket Token
The ‘‘expanded socket’’ token ...

XXXXX

Seq Token
The ‘‘seq’’ token contains a unique and monotonically increasing audit event sequence ID. Due to the limited range of 32 bits, serial number arithmetic and caution should be used when comparing sequence numbers.

privilege Token
The ‘‘privilege’’ token ...

XXXXX

Use-of-auth Token
The ‘‘use-of-auth’’ token ...

XXXXX

Command Token
The ‘‘command’’ token ...

XXXXX

ACL Token
The ‘‘ACL’’ token ...

XXXXX

Zonename Token
The ‘‘zonename’’ token ...

XXXXX

SEE ALSO

auditreduce(1), praudit(1), libbsm(3), audit(4), auditpipe(4), audit(8)

HISTORY

The OpenBSM implementation was created by McAfee Research, the security division of McAfee Inc., under contract to Apple Computer Inc. in 2004. It was subsequently adopted by the TrustedBSD Project as the foundation for the OpenBSM distribution.

AUTHORS

The Basic Security Module (BSM) interface to audit records and audit event stream format were defined by Sun Microsystems.

This manual page was written by Robert Watson 〈rwatson@FreeBSD.org〉.

BUGS

The ‘‘How to print’’ field in the ‘‘arbitrary data’’ token has undefined values.

The ‘‘in_addr’’ and ‘‘in_addr_ex’’ token layout documented here appears to be in conflict with the libbsm(3) implementations of au_to_in_addr(3) and au_to_in_addr_ex(3).

MidnightBSD 0.3 November 5, 2006 MidnightBSD 0.3